airglow imaging observations: Topics by Science.gov

The advances in airglow study and observation by the ground-based airglow observation network over China

NASA Astrophysics Data System (ADS)

Xu, Jiyao; Li, Qinzeng; Yuan, Wei; Liu, Xiao; Liu, Weijun; Sun, Longchang

2017-04-01

Ground-based airglow observation networks over China used to study airglow have been established, which contains 15 stations. Some new results were obtained using the networks. For OH airglow observations, firstly, an unusual outbreak of Concentric Gravity Wave (CGW) events were observed by the first no-gap network nearly every night during the first half of August 2013. Combination of the ground imager network with satellites provides multilevel observations of the CGWs from the troposphere to the mesopause region. Secondly, three-year OH airglow images (2012-2014) from Qujing (25.6°N, 103.7°E) were used to study how orographic features of the Tibetan Plateau (TP) affect the geographical distributions of gravity wave (GW) sources. We find the orographic forcings have a significant impact on the gravity wave propagation features. Thirdly, ground-based observations of the OH (9-4, 8-3, 6-2, 5-1, 3-0) band airglow over Xinglong (40°2N, 117°4E) in northern China from 2012 to 2014 are used to calculate rotational temperatures. By comparing the ground-based OH rotational temperature with SABER's observations, five Einstein coefficient datasets are evaluated. We find rotational temperatures determined using any of the available Einstein coefficient datasets have systematic errors. We have obtained a set of optimal Einstein coefficients ratios for rotational temperature derivation using three years data from ground-based OH spectra and SABER temperatures. For the OI 630.0 nm airglow observations, we used three-year (2011-2013) observations of thermospheric winds (at 250 km) by Fabry-Perot interferometers at Xinglong to study the climatology of atmospheric planetary wave-type oscillations (PWTOs) with periods of 4-19 days. We found these PWTOs occur more frequently in the months from May to October. They are consistent with the summertime preference of middle-latitude ionospheric electron density oscillations noted in other studies. By using an all-sky airglow imager
MANGO Imager Network Observations of Geomagnetic Storm Impact on Midlatitude 630 nm Airglow Emissions

NASA Astrophysics Data System (ADS)

Kendall, E. A.; Bhatt, A.

2017-12-01

The Midlatitude Allsky-imaging Network for GeoSpace Observations (MANGO) is a network of imagers filtered at 630 nm spread across the continental United States. MANGO is used to image large-scale airglow and aurora features and observes the generation, propagation, and dissipation of medium and large-scale wave activity in the subauroral, mid and low-latitude thermosphere. This network consists of seven all-sky imagers providing continuous coverage over the United States and extending south into Mexico. This network sees high levels of medium and large scale wave activity due to both neutral and geomagnetic storm forcing. The geomagnetic storm observations largely fall into two categories: Stable Auroral Red (SAR) arcs and Large-scale traveling ionospheric disturbances (LSTIDs). In addition, less-often observed effects include anomalous airglow brightening, bright swirls, and frozen-in traveling structures. We will present an analysis of multiple events observed over four years of MANGO network operation. We will provide both statistics on the cumulative observations and a case study of the "Memorial Day Storm" on May 27, 2017.
Statistical analysis of gravity waves characteristics observed by airglow imaging at Syowa Station (69S, 39E), Antarctica

NASA Astrophysics Data System (ADS)

Matsuda, Takashi S.; Nakamura, Takuji; Shiokawa, Kazuo; Tsutsumi, Masaki; Suzuki, Hidehiko; Ejiri, Mitsumu K.; Taguchi, Makoto

Atmospheric gravity waves (AGWs), which are generated in the lower atmosphere, transport significant amount of energy and momentum into the mesosphere and lower thermosphere and cause the mean wind accelerations in the mesosphere. This momentum deposit drives the general circulation and affects the temperature structure. Among many parameters to characterize AGWs, horizontal phase velocity is very important to discuss the vertical propagation. Airglow imaging is a useful technique for investigating the horizontal structures of AGWs at around 90 km altitude. Recently, there are many reports about statistical characteristics of AGWs observed by airglow imaging. However, comparison of these results obtained at various locations is difficult because each research group uses its own method for extracting and analyzing AGW events. We have developed a new statistical analysis method for obtaining the power spectrum in the horizontal phase velocity domain from airglow image data, so as to deal with huge amounts of imaging data obtained on different years and at various observation sites, without bias caused by different event extraction criteria for the observer. This method was applied to the data obtained at Syowa Station, Antarctica, in 2011 and compared with a conventional event analysis in which the phase fronts were traced manually in order to estimate horizontal characteristics. This comparison shows that our new method is adequate to deriving the horizontal phase velocity characteristics of AGWs observed by airglow imaging technique. We plan to apply this method to airglow imaging data observed at Syowa Station in 2002 and between 2008 and 2013, and also to the data observed at other stations in Antarctica (e.g. Rothera Station (67S, 68W) and Halley Station (75S, 26W)), in order to investigate the behavior of AGWs propagation direction and source distribution in the MLT region over Antarctica. In this presentation, we will report interim analysis result of the data
Comparison with the horizontal phase velocity distribution of gravity waves observed airglow imaging data of different sampling periods

NASA Astrophysics Data System (ADS)

Matsuda, T. S.; Nakamura, T.; Ejiri, M. K.; Tsutsumi, M.; Shiokawa, K.

2014-12-01

Atmospheric gravity waves (AGWs), which are generated in the lower atmosphere, transport significant amount of energy and momentum into the mesosphere and lower thermosphere. Among many parameters to characterize AGWs, horizontal phase velocity is very important to discuss the vertical propagation. Airglow imaging is a useful technique for investigating the horizontal structures of AGWs around mesopause. There are many airglow imagers operated all over the world, and a large amount of data which could improve our understanding of AGWs propagation direction and source distribution in the MLT region. We have developed a new statistical analysis method for obtaining the power spectrum in the horizontal phase velocity domain (phase velocity spectrum), from airglow image data, so as to deal with huge amounts of imaging data obtained on different years and at various observation sites, without bias caused by different event extraction criteria for the observer. From a series of images projected onto the geographic coordinates, 3-D Fourier transform is applied and 3-D power spectrum in horizontal wavenumber and frequency domain is obtained. Then, it is converted into phase velocity and frequency domain. Finally, the spectrum is integrated along the frequency for the range of interest and 2-D spectrum in horizontal phase velocity is calculated. This method was applied to the data obtained at Syowa Station (69ºS, 40ºE), Antarctica, in 2011 and compared with a conventional event analysis in which the phase fronts were traced manually in order to estimate horizontal propagation characteristics. This comparison shows that our new method is adequate to deriving the horizontal phase velocity characteristics of AGWs observed by airglow imaging technique. Airglow imaging observation has been operated with various sampling intervals. We also presents how the images with different sample interval should be treated.
Telescopic Imaging of Heater-Induced Airglow at HAARP

DTIC Science & Technology

2007-01-01

03-01-2007 Final1 10-09-2003 - 10-09-2006 4. TITLE AND SUBTITLE Ba. CONTRACT NUMBER Telescopic Imaging of Heater-Induced Airglow at HAARP N00014-03-1... HAARP to optically measure fine structure in the ionosphere and to study airglow sources. In the presence of aurora and a strong blanketing E layer... HAARP was modulated at intervals of several seconds. For several cycles, small bright airglow spots were observed whenever HAARP was on. These spots
Nighttime Medium-Scale Traveling Ionospheric Disturbances From Airglow Imager and Global Navigation Satellite Systems Observations

NASA Astrophysics Data System (ADS)

Huang, Fuqing; Lei, Jiuhou; Dou, Xiankang; Luan, Xiaoli; Zhong, Jiahao

2018-01-01

In this study, coordinated airglow imager, GPS total electron content (TEC), and Beidou geostationary orbit (GEO) TEC observations for the first time are used to investigate the characteristics of nighttime medium-scale traveling ionospheric disturbances (MSTIDs) over central China. The results indicated that the features of nighttime MSTIDs from three types of observations are generally consistent, whereas the nighttime MSTID features from the Beidou GEO TEC are in better agreement with those from airglow images as compared with the GPS TEC, given that the nighttime MSTID characteristics from GPS TEC are significantly affected by Doppler effect due to satellite movement. It is also found that there are three peaks in the seasonal variations of the occurrence rate of nighttime MSTIDs in 2016. Our study revealed that the Beidou GEO satellites provided fidelity TEC observations to study the ionospheric variability.
Gravity Wave Detection through All-sky Imaging of Airglow

NASA Astrophysics Data System (ADS)

Nguyen, T. V.; Martinez, A.; Porat, I.; Hampton, D. L.; Bering, E., III; Wood, L.

2017-12-01

Airglow, the faint glow of the atmosphere, is caused by the interaction of air molecules with radiation from the sun. Similarly, the aurora is created by interactions of air molecules with the solar wind. It has been shown that airglow emissions are altered by gravity waves passing through airglow source region (100-110km), making it possible to study gravity waves and their sources through airglow imaging. University of Houston's USIP - Airglow team designed a compact, inexpensive all-sky imager capable of detecting airglow and auroral emissions using a fisheye lens, a simple optical train, a filter wheel with 4 specific filters, and a CMOS camera. This instrument has been used in USIP's scientific campaign in Alaska throughout March 2017. During this period, the imager captured auroral activity in the Fairbanks region. Due to lunar conditions and auroral activity images from the campaign did not yield visible signs of airglow. Currently, the team is trying to detect gravity wave patterns present in the images through numerical analysis. Detected gravity wave patterns will be compared to local weather data, and may be used to make correlations between gravity waves and weather events. Such correlations could provide more data on the relationship between the mesosphere and lower layers of the atmosphere. Practical applications of this research include weather prediction and detection of air turbulence.
WINDII atmospheric wave airglow imaging

NASA Technical Reports Server (NTRS)

Armstrong, W. T.; Hoppe, U.-P.; Solheim, B. H.; Shepherd, G. G.

1996-01-01

Preliminary WINDII nighttime airglow wave-imaging data in the UARS rolldown attitude has been analyzed with the goal to survey gravity waves near the upper boundary of the middle atmosphere. Wave analysis is performed on O[sub 2](0,0) emissions from a selected 1[sup 0] x 1[sup 0] oblique view of the airglow layer at approximately 95 km altitude, which has no direct earth background and only an atmospheric background which is optically thick for the 0[sub 2](0,0) emission. From a small data set, orbital imaging of atmospheric wave structures is demonstrated, with indication of large variations in wave activity across land and sea. Comparison ground-based imagery is discussed with respect to similarity of wave variations across land/sea boundaries and future orbital mosaic image construction.
First OH Airglow Observation of Mesospheric Gravity Waves Over European Russia Region

NASA Astrophysics Data System (ADS)

Li, Qinzeng; Yusupov, Kamil; Akchurin, Adel; Yuan, Wei; Liu, Xiao; Xu, Jiyao

2018-03-01

For the first time, we perform a study of mesospheric gravity waves (GWs) for four different seasons of 1 year in the latitudinal band from 45°N to 75°N using an OH all-sky airglow imager over Kazan (55.8°N, 49.2°E), Russia, during the period of August 2015 to July 2016. Our observational study fills a huge airglow imaging observation gap in Europe and Russia region. In total, 125 GW events and 28 ripple events were determined by OH airglow images in 98 clear nights. The observed GWs showed a strong preference of propagation toward northeast in all seasons, which was significantly different from airglow imager observations at other latitudes that the propagation directions were seasonal dependent. The middle atmosphere wind field is used to explain the lack of low phase speed GWs since these GWs were falling into the blocking region due to the filtering effects. Deep tropospheric convections derived from the European Centre for Medium-Range Weather Forecasts reanalysis data are determined near Caucasus Mountains region, which suggests that the convections are the dominant source of the GWs in spring, summer, and autumn seasons. This finding extends our knowledge that convection might also be an important source of GWs in the higher latitudes. In winter the generation mechanism of the GWs are considered to be jet stream systems. In addition, the occurrence frequency of ripple is much lower than other stations. This study provides some constraints on the range of GW parameters in GW parameterization in general circulation models in Europe and Russia region.
New statistical analysis of the horizontal phase velocity distribution of gravity waves observed by airglow imaging

NASA Astrophysics Data System (ADS)

Matsuda, Takashi S.; Nakamura, Takuji; Ejiri, Mitsumu K.; Tsutsumi, Masaki; Shiokawa, Kazuo

2014-08-01

We have developed a new analysis method for obtaining the power spectrum in the horizontal phase velocity domain from airglow intensity image data to study atmospheric gravity waves. This method can deal with extensive amounts of imaging data obtained on different years and at various observation sites without bias caused by different event extraction criteria for the person processing the data. The new method was applied to sodium airglow data obtained in 2011 at Syowa Station (69°S, 40°E), Antarctica. The results were compared with those obtained from a conventional event analysis in which the phase fronts were traced manually in order to estimate horizontal characteristics, such as wavelengths, phase velocities, and wave periods. The horizontal phase velocity of each wave event in the airglow images corresponded closely to a peak in the spectrum. The statistical results of spectral analysis showed an eastward offset of the horizontal phase velocity distribution. This could be interpreted as the existence of wave sources around the stratospheric eastward jet. Similar zonal anisotropy was also seen in the horizontal phase velocity distribution of the gravity waves by the event analysis. Both methods produce similar statistical results about directionality of atmospheric gravity waves. Galactic contamination of the spectrum was examined by calculating the apparent velocity of the stars and found to be limited for phase speeds lower than 30 m/s. In conclusion, our new method is suitable for deriving the horizontal phase velocity characteristics of atmospheric gravity waves from an extensive amount of imaging data.
Enhanced airglow at Titan

NASA Astrophysics Data System (ADS)

Royer, Emilie; Esposito, Larry; Wahlund, Jan-Erik

2016-06-01

The Cassini Ultraviolet Imaging Spectrograph (UVIS) instrument made thousand of observations of Titan since its arrival in the Saturnian system in 2004, but only few of them have been analyzed yet. Using the imaging capability of UVIS combined to a big data analytics approach, we have been able to uncover an unexpected pattern in this observations: on several occasions the Titan airglow exhibits an enhanced brightness by approximately a factor of 2, generally combined with a lower altitude of the airglow emission peak. These events typically last from 10 to 30 minutes and are followed and preceded by an airglow of regular and expected level of brightness and altitude. Observations made by the Cassini Plasma Spectrometer (CAPS) instrument onboard Cassini allowed us to correlate the enhanced airglow observed on T-32 with an electron burst. The timing of the burst and the level of energetic electrons (1 keV) observed by CAPS correspond to a brighter and lower than typical airglow displayed on the UVIS data. Furthermore, during T-32 Titan was inside the Saturn's magnetosheath and thus more subject to bombardment by energetic particles. However, our analysis demonstrates that the presence of Titan inside the magnetosheath is not a necessary condition for the production of an enhanced airglow, as we detected other similar events while Titan was within Saturn's magnetosphere. The study presented here aims to a better understanding of the interactions of Titan's upper atmosphere with its direct environment.
Detection of large-scale concentric gravity waves from a Chinese airglow imager network

NASA Astrophysics Data System (ADS)

Lai, Chang; Yue, Jia; Xu, Jiyao; Yuan, Wei; Li, Qinzeng; Liu, Xiao

2018-06-01

Concentric gravity waves (CGWs) contain a broad spectrum of horizontal wavelengths and periods due to their instantaneous localized sources (e.g., deep convection, volcanic eruptions, or earthquake, etc.). However, it is difficult to observe large-scale gravity waves of >100 km wavelength from the ground for the limited field of view of a single camera and local bad weather. Previously, complete large-scale CGW imagery could only be captured by satellite observations. In the present study, we developed a novel method that uses assembling separate images and applying low-pass filtering to obtain temporal and spatial information about complete large-scale CGWs from a network of all-sky airglow imagers. Coordinated observations from five all-sky airglow imagers in Northern China were assembled and processed to study large-scale CGWs over a wide area (1800 km × 1 400 km), focusing on the same two CGW events as Xu et al. (2015). Our algorithms yielded images of large-scale CGWs by filtering out the small-scale CGWs. The wavelengths, wave speeds, and periods of CGWs were measured from a sequence of consecutive assembled images. Overall, the assembling and low-pass filtering algorithms can expand the airglow imager network to its full capacity regarding the detection of large-scale gravity waves.
Thermospheric Airglow Perturbations in the Upper Atmosphere Caused by Hurricane Harvey

NASA Astrophysics Data System (ADS)

Bhatt, A.; Kendall, E. A.

2017-12-01

The Midlatitude Allsky imaging Network for Geophysical Observations (MANGO) consists of seven allsky imagers distributed across the United States recording observations of large-scale airglow perturbations. The imagers are filtered at 630 nm, a forbidden oxygen line, in order to record the predominant source of airglow at 250 km altitude. While the ubiquitous airglow layer is challenging to observe when under uniform conditions, waves in the upper atmosphere cause ripples in the airglow layer which can easily be imaged by appropriate instrumentation. MANGO is the first network to record perturbations in the airglow layer on a continent-size scale. Large and Mid-scale Traveling Ionospheric Disturbances (LSTIDs and MSTIDs) are recorded that are caused by auroral forcing, mountain turbulence, and tidal variations. On August 25, airglow perturbations centered on the Hurricane Harvey path were observed by MANGO. These images and connections to other complimentary data sets such as GPS will be presented.
Imaging observations of lower thermospheric O(1S) and O2 airglow emissions from STS 9 - Implications of height variations

NASA Technical Reports Server (NTRS)

Swenson, G. R.; Mende, S. B.; Llewellyn, E. J.

1989-01-01

The lower thermospheric nightglow in the Southern Hemisphere was observed with the Atmospheric Emissions Photometric Imager during the Spacelab 1 mission in December, 1983. Observations of emission from O(1S) at 2972 and 5577A, O2 at 7620 A, OH near 6300 A, and the combined emission from the three upper states of O2 which lead to the Herzberg I and II and Chamberlain band emissions in B and near UV are discussed. The altitudes of peak emission heights are determined, showing that the peak heights are not constant with latitude. It is found that airglow heights varied with latitude by as much as 8 km. The observed airglow height pattern near the equator is similar to that of Wasser and Donahue (1979).
First spaceborne observation of the entire concentric airglow structure caused by tropospheric disturbance

NASA Astrophysics Data System (ADS)

Akiya, Y.; Saito, A.; Sakanoi, T.; Hozumi, Y.; Yamazaki, A.; Otsuka, Y.; Nishioka, M.; Tsugawa, T.

2014-10-01

Spaceborne imagers are able to observe the airglow structures with wide field of views regardless of the tropospheric condition that limits the observational time of the ground-based imagers. Concentric wave structures of the O2 airglow in 762 nm wavelength were observed over North America on 1 June 2013 from the International Space Station. This was the first observation in which the entire image of the structure was captured from space, and its spatial scale size was determined to be 1200 km radius without assumptions. The apparent horizontal wavelength was 80 km, and the amplitude in the intensity was approximately 20% of the background intensity. The propagation velocity of the structure was derived as 125 ± 62 m/s and atmospheric gravity waves were estimated to be generated for 3.5 ± 1.7 h. Concentric structures observed in this event were interpreted to be generated by super cells that caused a tornado in its early phase.
Issues in Quantitative Analysis of Ultraviolet Imager (UV) Data: Airglow

NASA Technical Reports Server (NTRS)

Germany, G. A.; Richards, P. G.; Spann, J. F.; Brittnacher, M. J.; Parks, G. K.

1999-01-01

The GGS Ultraviolet Imager (UVI) has proven to be especially valuable in correlative substorm, auroral morphology, and extended statistical studies of the auroral regions. Such studies are based on knowledge of the location, spatial, and temporal behavior of auroral emissions. More quantitative studies, based on absolute radiometric intensities from UVI images, require a more intimate knowledge of the instrument behavior and data processing requirements and are inherently more difficult than studies based on relative knowledge of the oval location. In this study, UVI airglow observations are analyzed and compared with model predictions to illustrate issues that arise in quantitative analysis of UVI images. These issues include instrument calibration, long term changes in sensitivity, and imager flat field response as well as proper background correction. Airglow emissions are chosen for this study because of their relatively straightforward modeling requirements and because of their implications for thermospheric compositional studies. The analysis issues discussed here, however, are identical to those faced in quantitative auroral studies.
Satellite-based observations of tsunami-induced mesosphere airglow perturbations

NASA Astrophysics Data System (ADS)

Yang, Yu-Ming; Verkhoglyadova, Olga; Mlynczak, Martin G.; Mannucci, Anthony J.; Meng, Xing; Langley, Richard B.; Hunt, Linda A.

2017-01-01

Tsunami-induced airglow emission perturbations were retrieved by using space-based measurements made by the Sounding of the Atmosphere using Broad-band Emission Radiometry (SABER) instrument on board the Thermosphere-Ionosphere-Mesosphere Energetics Dynamics spacecraft. At and after the time of the Tohoku-Oki earthquake on 11 March 2011, and the Chile earthquake on 16 September 2015, the spacecraft was performing scans over the Pacific Ocean. Significant ( 10% relative to the ambient emission profiles) and coherent nighttime airglow perturbations were observed in the mesosphere following Sounding of the Atmosphere using Broad-band Emission Radiometry limb scans intercepting tsunami-induced atmospheric gravity waves. Simulations of emission variations are consistent with the physical characteristics of the disturbances at the locations of the corresponding SABER scans. Airglow observations and model simulations suggest that atmospheric neutral density and temperature perturbations can lead to the observed amplitude variations and multipeak structures in the emission profiles. This is the first time that airglow emission rate perturbations associated with tsunamis have been detected with space-based measurements.
Enhanced 630nm equatorial airglow emission observed by Limb Viewing Hyper Spectral Imager (LiVHySI) onboard YOUTHSAT-1

NASA Astrophysics Data System (ADS)

Bisht, R. S.; Thapa, N.; Babu, P. N.

2016-04-01

The Earth's airglow layer, when observed in the limb view mode, appears to be a double layer. LiVHySI onboard YOUTHSAT (inclination 98.730, apogee 817 km, launched by Indian Space Research Organization in April, 2011) is an Earth's limb viewing camera measuring airglow emissions in the spectral window of 550-900 nm. Total altitude coverage is about 500 km with command selectable lowest altitude. During few of the orbits we have observed the double layer structure and obtained absolute spectral intensity and altitude profile for 630 nm airglow emission. Our night time observations of upper atmosphere above dip equator carried out on 3rd May, 2011 show a prominent 630 nm double layer structure. The upper airglow layer consists of the 630 nm atomic oxygen O(1D) emission line and lower layer consists of OH(9-3) meinel band emission at 630 nm. The volume emission rate as a function of altitude is simulated for our observational epoch and the modeled limb intensity distribution is compared with the observations. The observations are in good agreement with the simulated intensity distribution.
WINDII airglow observations of wave superposition and the possible association with historical "bright nights"

NASA Astrophysics Data System (ADS)

Shepherd, G. G.; Cho, Y.-M.

2017-07-01

Longitudinal variations of airglow emission rate are prominent in all midlatitude nighttime O(1S) lower thermospheric data obtained with the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS). The pattern generally appears as a combination of zonal waves 1, 2, 3, and 4 whose phases propagate at different rates. Sudden localized enhancements of 2 to 4 days duration are sometimes evident, reaching vertically integrated emission rates of 400 R, a factor of 10 higher than minimum values for the same day. These are found to occur when the four wave components come into the same phase at one longitude. It is shown that these highly localized longitudinal maxima are consistent with the historical phenomena known as "bright nights" in which the surroundings of human dark night observers were seen to be illuminated by this enhanced airglow.Plain Language SummaryFor centuries, going back to the Roman era, people have recorded experiences of brightened skies during the night, called "bright nights." Currently, scientists study airglow, an emission of light from the high atmosphere, 100 km above us. Satellite observations of a green airglow have shown that it consists of waves 1, 2, 3, and 4 around the earth. It happens that when the peaks of the different waves coincide there is an airglow brightening, and this article demonstrates that this event produces a bright night. The modern data are shown to be entirely consistent with the historical observations. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA....13380K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA....13380K">OH line selection for nadir airglow gravity wave imaging in the auroral zone</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kumer, J. B.; Hecht, J.; Geballe, T. R.; Mergenthaler, J. L.; Rinaldi, M.; Claflin, E. S.; Swenson, G. R. 2003-04-01 For satellite borne nadir OH airglow wave imaging in the auroral zone the observed lines must be strong enough to give good signal to noise, coincident with strong atmospheric absorption lines to suppress structure in the image due to reflection of airglow and moonlight from tops of clouds and from high altitude terrain, and in a spectral region coincident with relatively weak aurora that its contribution to the observed structure can be corrected by data obtained in a guard band containing relatively strong auroral emission, and relatively weak, or no airglow. OH airglow spectra observed from high altitude, in our case Mauna Kea by the UKIRT CGS4 grating instrument, (see website http://www.jach.hawaii.edu/JACpublic/UKIRT/instruments/cgs4/maunakea/ohlines.html) provide an opportunity to identify lines that ARE NOT observed at that high altitude. These are most absorbed in the earths atmosphere. These occur in the regions near 1400 and 1900 nm of strong water vapor absorption. Our preliminary determination is that the 7-5 p1(2) line at 1899.01 nm and the p1(3) at 1911.41 nm are the best candidates. These are missing in the observed spectra, and this is confirmed by running FASCODE transmission calculations from top of Mauna Kea to space at .01 cm-1 resolution. Similar calculations for conditions at which the high resolution Kitt peak atlas data were taken confirmed the calculations. OH line positions and relative strengths within the band were derived from the HITRAN data base, and transmitted lines in the 7-5 band were used to determine the strength of these lines. Each are the order 10 kR, and are about four to six times brighter than atmospheric absorbed candidate lines in the 1400 nm region. Also, the aurora in the 1900nm region is considerably weaker than in the 1400nm region. In fact the region 1351 to 1358 contains relatively strong aurora, and practically no airglow, and is candidate for an instrumental auroral guard band. The nadir imaging instrument which </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li class="active">1</li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_2" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active">2</li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="21"> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170003090&hterms=plasma&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dplasma','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170003090&hterms=plasma&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dplasma">Hemispheric Asymmetry in Transition from Equatorial Plasma Bubble to Blob as Deduced from 630.0 nm Airglow Observations at Low Latitudes</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Park, Jaeheung; Martinis, Carlos R.; Luehr, Hermann; Pfaff, Robert F.; Kwak, Young-Sil 2016-01-01 Transitions from depletions to enhancements of 630.0 nm nighttime airglow have been observed at Arecibo. Numerical simulations by Krall et al. (2009) predicted that they should occur only in one hemisphere, which has not yet been confirmed observationally. In this study we investigate the hemispheric conjugacy of the depletion-to-enhancement transition using multiple instruments. We focus on one event observed in the American longitude sector on 22 December 2014: 630.0 nm airglow depletions evolved into enhancements in the Northern Hemisphere while the evolution did not occur in the conjugate location in the Southern Hemisphere. Concurrent plasma density measured by low Earth orbit (LEO) satellites and 777.4 nm airglow images support that the depletions and enhancements of 630.0 nm night time airglow reflect plasma density decreases and increases (blobs), respectively. Characteristics of the airglow depletions, in the context of the LEO satellite data, further suggest that the plasma density depletion deduced from the airglow data represents equatorial plasma bubbles (EPBs) rather than medium-scale traveling ionospheric disturbances from midlatitudes. Hence, the event in this study can be interpreted as EPB-to-blob transition. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..121..650C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..121..650C">Intermittency of gravity wave momentum flux in the mesopause region observed with an all-sky airglow imager</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Cao, Bing; Liu, Alan Z. 2016-01-01 The intermittency of gravity wave momentum flux (MF) near the OH airglow layer (˜87 km) in the mesopause region is investigated for the first time using observation of all-sky airglow imager over Maui, Hawaii (20.7°N, 156.3°W), and Cerro Pachón, Chile (30.3°S, 70.7°W). At both sites, the probability density function (pdf) of gravity wave MF shows two distinct distributions depending on the magnitude of the MF. For MF smaller (larger) than ˜16 m2 s-2 (0.091 mPa), the pdf follows a lognormal (power law) distribution. The intermittency represented by the Bernoulli proxy and the percentile ratio shows that gravity waves have higher intermittency at Maui than at Cerro Pachón, suggesting more intermittent background variation above Maui. It is found that most of the MF is contributed by waves that occur very infrequently. But waves that individually contribute little MF are also important because of their higher occurrence frequencies. The peak contribution is from waves with MF around ˜2.2 m2 s-2 at Cerro Pachón and ˜5.5 m2 s-2 at Maui. Seasonal variations of the pdf and intermittency imply that the background atmosphere has larger influence on the observed intermittency in the mesopause region. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1065K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1065K">Mesopause region wind, temperature and airglow irradiance above Eureka, Nunavut</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kristoffersen, Samuel; Ward, William E.; Vail, Christopher; Shepherd, Marianna 2016-07-01 The PEARL All Sky Imager (PASI, airglow images), the Spectral Airglow Temperature Imager (SATI, airglow irradiance and temperature) and the E-Region Wind Interferometer II (ERWIN2, wind, airglow irradiance and temperature) are co-located at the Polar Environment Atmospheric Research Laboratory (PEARL)in Eureka, Nunavut (80 N, 86 W). These instruments view the wind, temperature and airglow irradiance of hydroxyl (all three) O2 (ERWIN2 and SATI), sodium (PASI), and oxygen green line (PASI and ERWIN2). The viewing locations and specific emissions of the various instruments differ. Nevertheless, the co-location of these instruments provides an excellent opportunity for case studies of specific events and for intercomparison between the different techniques. In this paper we discuss the approach we are using to combine observations from the different instruments. Case studies show that at times the various instruments are in good agreement but at other times they differ. Of particular interest are situations where gravity wave signatures are evident for an extended period of time and one such situation is presented. The discussion includes consideration of the filtering effect of viewing through airglow layers and the extent to which wind, airglow and temperature variations can be associated with the same gravity wave. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EP%26S...68..155H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EP%26S...68..155H">Calibration of imaging parameters for space-borne airglow photography using city light positions</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hozumi, Yuta; Saito, Akinori; Ejiri, Mitsumu K. 2016-09-01 A new method for calibrating imaging parameters of photographs taken from the International Space Station (ISS) is presented in this report. Airglow in the mesosphere and the F-region ionosphere was captured on the limb of the Earth with a digital single-lens reflex camera from the ISS by astronauts. To utilize the photographs as scientific data, imaging parameters, such as the angle of view, exact position, and orientation of the camera, should be determined because they are not measured at the time of imaging. A new calibration method using city light positions shown in the photographs was developed to determine these imaging parameters with high accuracy suitable for airglow study. Applying the pinhole camera model, the apparent city light positions on the photograph are matched with the actual city light locations on Earth, which are derived from the global nighttime stable light map data obtained by the Defense Meteorological Satellite Program satellite. The correct imaging parameters are determined in an iterative process by matching the apparent positions on the image with the actual city light locations. We applied this calibration method to photographs taken on August 26, 2014, and confirmed that the result is correct. The precision of the calibration was evaluated by comparing the results from six different photographs with the same imaging parameters. The precisions in determining the camera position and orientation are estimated to be ±2.2 km and ±0.08°, respectively. The 0.08° difference in the orientation yields a 2.9-km difference at a tangential point of 90 km in altitude. The airglow structures in the photographs were mapped to geographical points using the calibrated imaging parameters and compared with a simultaneous observation by the Visible and near-Infrared Spectral Imager of the Ionosphere, Mesosphere, Upper Atmosphere, and Plasmasphere mapping mission installed on the ISS. The comparison shows good agreements and supports the validity </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17794901','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17794901">Night Airglow Observations from Orbiting Spacecraft Compared with Measurements from Rockets.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Koomen, M J; Gulledge, I S; Packer, D M; Tousey, R 1963-06-07 A luminous band around the night-time horizon, observed from orbiting capsules by J. H. Glenn and M. S. Carpenter, and identified as the horizon enhancement of the night airglow, is detected regularly in rocket-borne studies of night airglow. Values of luminance and dip angle of this band derived from Carpenter's observations agree remarkably well with values obtained from rocket data. The rocket results, however, do not support Carpenter's observation that the emission which he saw was largely the atomic oxygen line at 5577 A, but assign the principal luminosity to the green continuum. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930005120','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930005120">Near-infrared oxygen airglow from the Venus nightside</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Crisp, D.; Meadows, V. S.; Allen, D. A.; Bezard, B.; Debergh, C.; Maillard, J.-P. 1992-01-01 Groundbased imaging and spectroscopic observations of Venus reveal intense near-infrared oxygen airglow emission from the upper atmosphere and provide new constraints on the oxygen photochemistry and dynamics near the mesopause (approximately 100 km). Atomic oxygen is produced by the Photolysis of CO2 on the dayside of Venus. These atoms are transported by the general circulation, and eventually recombine to form molecular oxygen. Because this recombination reaction is exothermic, many of these molecules are created in an excited state known as O2(delta-1). The airglow is produced as these molecules emit a photon and return to their ground state. New imaging and spectroscopic observations acquired during the summer and fall of 1991 show unexpected spatial and temporal variations in the O2(delta-1) airglow. The implications of these observations for the composition and general circulation of the upper venusian atmosphere are not yet understood but they provide important new constraints on comprehensive dynamical and chemical models of the upper mesosphere and lower thermosphere of Venus. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSA33A2422S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSA33A2422S">Performance evaluation of low-cost airglow cameras for mesospheric gravity wave measurements</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Suzuki, S.; Shiokawa, K. 2016-12-01 Atmospheric gravity waves significantly contribute to the wind/thermal balances in the mesosphere and lower thermosphere (MLT) through their vertical transport of horizontal momentum. It has been reported that the gravity wave momentum flux preferentially associated with the scale of the waves; the momentum fluxes of the waves with a horizontal scale of 10-100 km are particularly significant. Airglow imaging is a useful technique to observe two-dimensional structure of small-scale (<100 km) gravity waves in the MLT region and has been used to investigate global behaviour of the waves. Recent studies with simultaneous/multiple airglow cameras have derived spatial extent of the MLT waves. Such network imaging observations are advantageous to ever better understanding of coupling between the lower and upper atmosphere via gravity waves. In this study, we newly developed low-cost airglow cameras to enlarge the airglow imaging network. Each of the cameras has a fish-eye lens with a 185-deg field-of-view and equipped with a CCD video camera (WATEC WAT-910HX) ; the camera is small (W35.5 x H36.0 x D63.5 mm) and inexpensive, much more than the airglow camera used for the existing ground-based network (Optical Mesosphere Thermosphere Imagers (OMTI) operated by Solar-Terrestrial Environmental Laboratory, Nagoya University), and has a CCD sensor with 768 x 494 pixels that is highly sensitive enough to detect the mesospheric OH airglow emission perturbations. In this presentation, we will report some results of performance evaluation of this camera made at Shigaraki (35-deg N, 136-deg E), Japan, where is one of the OMTI station. By summing 15-images (i.e., 1-min composition of the images) we recognised clear gravity wave patterns in the images with comparable quality to the OMTI's image. Outreach and educational activities based on this research will be also reported. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA13B..07G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA13B..07G">NIRAC: Near Infrared Airglow Camera for the International Space Station</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gelinas, L. J.; Rudy, R. J.; Hecht, J. H. 2017-12-01 NIRAC is a space based infrared airglow imager that will be deployed to the International Space Station in late 2018, under the auspices of the Space Test Program. NIRAC will survey OH airglow emissions in the 1.6 micron wavelength regime, exploring the spatial and temporal variability of emission intensities at latitudes from 51° south to 51° north. Atmospheric perturbations in the 80-100 km altitude range, including those produced by atmospheric gravity waves (AGWs), are observable in the OH airglow. The objective of the NIRAC experiment is to make near global measurement of the OH airglow and airglow perturbations. These emissions also provide a bright source of illumination at night, allowing for nighttime detection of clouds and surface characteristics. The instrument, developed by the Aerospace Space Science Applications Laboratory, employs a space-compatible FPGA for camera control and data collection and a novel, custom optical system to eliminate image smear due to orbital motion. NIRAC utilizes a high-performance, large format infrared focal plane array, transitioning technology used in the existing Aerospace Corporation ground-based airglow imager to a space based platform. The high-sensitivity, four megapixel imager has a native spatial resolution of 100 meters at ISS altitudes. The 23° x 23° FOV sweeps out a 150 km swath of the OH airglow layer as viewed from the ISS, and is sensitive to OH intensity perturbations down to 0.1%. The detector has a 1.7 micron cutoff that precludes the need for cold optics and reduces cooling requirements (to 180 K). Detector cooling is provided by a compact, lightweight cryocooler capable of reaching 120K, providing a great deal of margin. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JASTP.154...33C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JASTP.154...33C">Case study of convective instability observed in airglow images over the Northeast of Brazil</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Carvalho, A. J. A.; Paulino, I.; Medeiros, A. F.; Lima, L. M.; Buriti, R. A.; Paulino, A. R.; Wrasse, C. M.; Takahashi, H. 2017-02-01 An intense activity of ripples during the nighttime was observed in airglow images over São João do Cariri (36.5° W, 7.4° S) on 10 October 2004 which lasted for two hours. Those ripples appeared simultaneously with the crossing of a mesospheric front and medium scale gravity waves. The ripples occurred ahead of the mesospheric front and their phase front were almost parallel to the phase of the mesospheric front and were almost perpendicular to the phase front of the gravity wave. Using wind measurements from a meteor radar located at São João do Cariri and simultaneous vertical temperature profiles from the TIMED/SABER satellite, on the night of the events and within the imager field of view, the atmospheric background environment in the mesosphere and lower thermosphere (MLT) was investigated in order to understand the instability process that caused the appearance of the ripples. Dynamic and convective instabilities have been pointed out as responsible for creation of ripples in the MLT. The observed ripples were advected by the neutral wind, they occurred into a region with negative lapse rate of the potential temperature and the Richardson number was negative as well. According to these characteristics, the ripple structures could be generated in the MLT region due to the predominance of convective instability. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSA31A2387B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSA31A2387B">Mid-latitude response to geomagnetic storms observed in 630nm airglow over continental United States</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bhatt, A.; Kendall, E. A. 2016-12-01 We present analysis of mid-latitude response observed to geomagnetic storms using the MANGO network consisting of all-sky cameras imaging 630nm emission over the continental United States. The response largely falls in two categories: Stable Auroral Red (SAR) arc and Large-scale traveling ionospheric disturbances (LSTIDs). However, outside of these phenomena, less often observed response include anomalous airglow brightening, bright swirls, and frozen in traveling structures. We will present an analysis of various events observed over 3 years of MANGO network operation, which started with two imagers in the western US with addition of new imagers in the last year. We will also present unusual north and northeastward propagating waves often observed in conjunction with diffuse aurora. Wherever possible, we will compare with observations from Boston University imagers located in Massachusetts and Texas. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.4628Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.4628Y">Peak height of OH airglow derived from simultaneous observations a Fabry-Perot interferometer and a meteor radar</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Yu, Tao; Zuo, Xiaomin; Xia, Chunliang; Li, Mingyuan; Huang, Cong; Mao, Tian; Zhang, Xiaoxin; Zhao, Biqiang; Liu, Libo 2017-04-01 A new method for estimating daily averaged peak height of the OH airglow layer from a ground-based meteor radar (MR) and a Fabry-Perot interferometer (FPI) is presented. The first results are derived from 4 year simultaneous measurements of winds by a MR and a FPI at two adjacent stations over center China and are compared with observations from the Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument. The OH airglow peak heights, which are derived by using correlation analysis between winds of the FPI and MR, are found to generally peak at an altitude of 87 km and frequently varied between 80 km and 90 km day to day. In comparison with SABER OH 1.6 μm observations, reasonable similarity of airglow peak heights is found, and rapid day-to-day variations are also pronounced. Lomb-Scargle analysis is used to determine cycles of temporal variations of airglow peak heights, and there are obvious periodic variations both in our airglow peak heights and in the satellite observations. In addition to the annual, semiannual, monthly, and three monthly variations, the shorter time variations, e.g., day-to-day and several days' variations, are also conspicuous. The day-to-day variations of airglow height obviously could reduce observation accuracy and lead to some deviations in FPI measurements. These FPI wind deviations arising from airglow height variations are also estimated to be about 3-5 m/s from 2011 to 2015, with strong positive correlation with airglow peak height variation. More attention should be paid to the wind deviations associated with airglow height variation when using and interpreting winds measured by FPI. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSA21B2025K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSA21B2025K">HF-induced airglow structure as a proxy for ionospheric irregularity detection</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kendall, E. A. 2013-12-01 The High Frequency Active Auroral Research Program (HAARP) heating facility allows scientists to test current theories of plasma physics to gain a better understanding of the underlying mechanisms at work in the lower ionosphere. One powerful technique for diagnosing radio frequency interactions in the ionosphere is to use ground-based optical instrumentation. High-frequency (HF), heater-induced artificial airglow observations can be used to diagnose electron energies and distributions in the heated region, illuminate natural and/or artificially induced ionospheric irregularities, determine ExB plasma drifts, and measure quenching rates by neutral species. Artificial airglow is caused by HF-accelerated electrons colliding with various atmospheric constituents, which in turn emit a photon. The most common emissions are 630.0 nm O(1D), 557.7 nm O(1S), and 427.8 nm N2+(1NG). Because more photons will be emitted in regions of higher electron energization, it may be possible to use airglow imaging to map artificial field-aligned irregularities at a particular altitude range in the ionosphere. Since fairly wide field-of-view imagers are typically deployed in airglow campaigns, it is not well-known what meter-scale features exist in the artificial airglow emissions. Rocket data show that heater-induced electron density variations, or irregularities, consist of bundles of ~10-m-wide magnetic field-aligned filaments with a mean depletion depth of 6% [Kelley et al., 1995]. These bundles themselves constitute small-scale structures with widths of 1.5 to 6 km. Telescopic imaging provides high resolution spatial coverage of ionospheric irregularities and goes hand in hand with other observing techniques such as GPS scintillation, radar, and ionosonde. Since airglow observations can presumably image ionospheric irregularities (electron density variations), they can be used to determine the spatial scale variation, the fill factor, and the lifetime characteristics of </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AnGeo..34..293P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AnGeo..34..293P">Periodic waves in the lower thermosphere observed by OI630 nm airglow images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Paulino, I.; Medeiros, A. F.; Vadas, S. L.; Wrasse, C. M.; Takahashi, H.; Buriti, R. A.; Leite, D.; Filgueira, S.; Bageston, J. V.; Sobral, J. H. A.; Gobbi, D. 2016-02-01 Periodic wave structures in the thermosphere have been observed at São João do Cariri (geographic coordinates: 36.5° W, 7.4° S; geomagnetic coordinates based on IGRF model to 2015: 35.8° E, 0.48° N) from September 2000 to November 2010 using OI630.0 nm airglow images. During this period, which corresponds to almost one solar cycle, characteristics of 98 waves were studied. Similarities between the characteristics of these events and observations at other places around the world were noted, primarily the spectral parameters. The observed periods were mostly found between 10 and 35 min; horizontal wavelengths ranged from 100 to 200 km, and phase speed from 30 to 180 m s-1. These parameters indicated that some of the waves, presented here, are slightly faster than those observed previously at low and middle latitudes (Indonesia, Carib and Japan), indicating that the characteristics of these waves may change at different places. Most of observed waves have appeared during magnetically quiet nights, and the occurrence of those waves followed the solar activity. Another important characteristic is the quasi-monochromatic periodicity that distinguish them from the single-front medium-scale traveling ionospheric disturbances (MSTIDs) that have been observed previously over the Brazilian region. Moreover, most of the observed waves did not present a phase front parallel to the northeast-southwest direction, which is predicted by the Perkins instability process. It strongly suggests that most of these waves must have had different generation mechanisms from the Perkins instability, which have been pointed out as being a very important mechanism for the generation of MSTIDs in the lower thermosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912782S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912782S">High resolution observations of small-scale gravity waves and turbulence features in the OH airglow layer</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sedlak, René; Hannawald, Patrick; Schmidt, Carsten; Wüst, Sabine; Bittner, Michael 2017-04-01 A new version of the Fast Airglow Imager (FAIM) for the detection of atmospheric waves in the OH airglow layer has been set up at the German Remote Sensing Data Centre (DFD) of the German Aerospace Centre (DLR) at Oberpfaffenhofen (48.09 ° N, 11.28 ° E), Germany. The spatial resolution of the instrument is 17 m/pixel in zenith direction with a field of view (FOV) of 11.1 km x 9.0 km at the OH layer height of ca. 87 km. Since November 2015, the system has been in operation in two different setups (zenith angles 46 ° and 0 °) with a temporal resolution of 2.5 to 2.8 s. In a first case study we present observations of two small wave-like features that might be attributed to gravity wave instabilities. In order to spectrally analyse harmonic structures even on small spatial scales down to 550 m horizontal wavelength, we made use of the Maximum Entropy Method (MEM) since this method exhibits an excellent wavelength resolution. MEM further allows analysing relatively short data series, which considerably helps to reduce problems such as stationarity of the underlying data series from a statistical point of view. We present an observation of the subsequent decay of well-organized wave fronts into eddies, which we tentatively interpret in terms of an indication for the onset of turbulence. Another remarkable event which demonstrates the technical capabilities of the instrument was observed during the night of 4th to 5th April 2016. It reveals the disintegration of a rather homogenous brightness variation into several filaments moving in different directions and with different speeds. It resembles the formation of a vortex with a horizontal axis of rotation likely related to a vertical wind shear. This case shows a notable similarity to what is expected from theoretical modelling of Kelvin-Helmholtz instabilities (KHIs). The comparatively high spatial resolution of the presented new version of the FAIM airglow imager provides new insights into the structure of </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AMT....10.3093F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AMT....10.3093F">Optimizing hydroxyl airglow retrievals from long-slit astronomical spectroscopic observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Franzen, Christoph; Hibbins, Robert Edward; Espy, Patrick Joseph; Djupvik, Anlaug Amanda 2017-08-01 Astronomical spectroscopic observations from ground-based telescopes contain background emission lines from the terrestrial atmosphere's airglow. In the near infrared, this background is composed mainly of emission from Meinel bands of hydroxyl (OH), which is produced in highly excited vibrational states by reduction of ozone near 90 km. This emission contains a wealth of information on the chemical and dynamical state of the Earth's atmosphere. However, observation strategies and data reduction processes are usually optimized to minimize the influence of these features on the astronomical spectrum. Here we discuss a measurement technique to optimize the extraction of the OH airglow signal itself from routine J-, H-, and K-band long-slit astronomical spectroscopic observations. As an example, we use data recorded from a point-source observation by the Nordic Optical Telescope's intermediate-resolution spectrograph, which has a spatial resolution of approximately 100 m at the airglow layer. Emission spectra from the OH vibrational manifold from v' = 9 down to v' = 3, with signal-to-noise ratios up to 280, have been extracted from 10.8 s integrations. Rotational temperatures representative of the background atmospheric temperature near 90 km, the mesosphere and lower thermosphere region, can be fitted to the OH rotational lines with an accuracy of around 0.7 K. Using this measurement and analysis technique, we derive a rotational temperature distribution with v' that agrees with atmospheric model conditions and the preponderance of previous work. We discuss the derived rotational temperatures from the different vibrational bands and highlight the potential for both the archived and future observations, which are at unprecedented spatial and temporal resolutions, to contribute toward the resolution of long-standing problems in atmospheric physics. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMNH51A1922G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMNH51A1922G">Methods for analyzing optical observations of tsunami-induced signatures in airglow emissions from ground-based and space-based platforms</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Grawe, M.; Makela, J. J. 2016-12-01 Airglow imaging of the 630.0-nm redline emission has emerged as a useful tool for studying the properties of tsunami-ionospheric coupling in recent years, offering spatially continuous coverage of the sky with a single instrument. Past studies have shown that airglow signatures induced by tsunamis are inherently anisotropic due to the observation geometry and effects from the geomagnetic field. Here, we present details behind the techniques used to determine the parameters of the signature (orientation, wavelength, etc) with potential extensions to real or quasi-real time and a tool for interpreting the location and strength of the signatures in the field of view. We demonstrate application of the techniques to ground-based optical measurements of several tsunami-induced signatures taking place over the past five years from an imaging system in Hawaii. Additionally, these methods are extended for use on space-based observation platforms, offering advantages over ground-based installations. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA33A2575F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA33A2575F">Small-Scale Dynamical Structures Using OH Airglow From Astronomical Observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Franzen, C.; Espy, P. J.; Hibbins, R. E.; Djupvik, A. A. 2017-12-01 Remote sensing of perturbations in the hydroxyl (OH) Meinel airglow has often been used to observe gravity, tidal and planetary waves travelling through the 80-90 km region. While large scale (>1 km) gravity waves and the winds caused by their breaking are widely documented, information on the highest frequency waves and instabilities occurring during the breaking process is often limited by the temporal and spatial resolution of the available observations. In an effort to better quantify the full range of wave scales present near the mesopause, we present a series of observations of the OH Meinel (9,7) transition that were executed with the Nordic Optical Telescope on La Palma (18°W, 29°N). These measurements have a 24 s repetition rate and horizontal spatial resolutions at 87 km as small as 10 cm, allowing us to quantify the transition in the mesospheric wave domains as the gravity waves break. Temporal scales from hours to minutes, as well as sub-100 m coherent structures in the OH airglow have been observed and will be presented. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.1363T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.1363T">Plans of lightning and airglow measurements with LAC/Akatsuki</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Takahashi, Yukihiro; Hoshino, Naoya; Sato, Mitsuteru; Yair, Yoav; Galand, Marina; Fukuhara, Tetsuya Though there are extensive researches on the existence of lightning discharge in Venus over few decades, this issue is still under controversial. Recently it is reported that the magnetometer on board Venus Express detected whistler mode waves whose source could be lightning discharge occurring well below the spacecraft. However, it is too early to determine the origin of these waves. On the other hand, night airglow is expected to provide essential information on the atmospheric circulation in the upper atmosphere of Venus. But the number of consecutive images of airglow obtained by spacecraft is limited and even the variations of most enhanced location is still unknown. In order to identify the discharge phenomena in the atmosphere of Venus separating from noises and to know the daily variation of airglow distribution in night-side disk, we plan to observe the lightning and airglow optical emissions with high-speed and high-sensitivity optical detector with narrow-band filters on board Akatsuki. We are ready to launch the flight model of lightning and airglow detector, LAC (Lightning and Airglow Camera). Main difference from other previous equipments which have provided evidences of lightning existence in Venus is the high-speed sampling rate at 32 us interval for each pixel, enabling us to distinguish the optical lightning flash from other pulsing noises. In this presentation the observation strategies, including ground-based support with optical telescopes, are shown and discussed. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850067068&hterms=ionospheric+modification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dionospheric%2Bmodification','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850067068&hterms=ionospheric+modification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dionospheric%2Bmodification">Simulations and observations of plasma depletion, ion composition, and airglow emissions in two auroral ionospheric depletion experiments</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Yau, A. W.; Whalen, B. A.; Harris, F. R.; Gattinger, R. L.; Pongratz, M. B. 1985-01-01 Observations of plasma depletion, ion composition modification, and airglow emissions in the Waterhole experiments are presented. The detailed ion chemistry and airglow emission processes related to the ionospheric hole formation in the experiment are examined, and observations are compared with computer simulation results. The latter indicate that the overall depletion rates in different parts of the depletion region are governed by different parameters. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AdSpR..54..554B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AdSpR..54..554B">Limb Viewing Hyper Spectral Imager (LiVHySI) for airglow measurements onboard YOUTHSAT-1</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bisht, R. S.; Hait, A. K.; Babu, P. N.; Sarkar, S. S.; Benerji, A.; Biswas, A.; Saji, A. K.; Samudraiah, D. R. M.; Kirankumar, A. S.; Pant, T. K.; Parimalarangan, T. 2014-08-01 The Limb Viewing Hyper Spectral Imager (LiVHySI) is one of the Indian payloads onboard YOUTHSAT (inclination 98.73°, apogee 817 km) launched in April, 2011. The Hyper-spectral imager has been operated in Earth’s limb viewing mode to measure airglow emissions in the spectral range 550-900 nm, from terrestrial upper atmosphere (i.e. 80 km altitude and above) with a line-of-sight range of about 3200 km. The altitude coverage is about 500 km with command selectable lowest altitude. This imaging spectrometer employs a Linearly Variable Filter (LVF) to generate the spectrum and an Active Pixel Sensor (APS) area array of 256 × 512 pixels, placed in close proximity of the LVF as detector. The spectral sampling is done at 1.06 nm interval. The optics used is an eight element f/2 telecentric lens system with 80 mm effective focal length. The detector is aligned with respect to the LVF such that its 512 pixel dimension covers the spectral range. The radiometric sensitivity of the imager is about 20 Rayleigh at noise floor through the signal integration for 10 s at wavelength 630 nm. The imager is being operated during the eclipsed portion of satellite orbits. The integration in the time/spatial domain could be chosen depending upon the season, solar and geomagnetic activity and/or specific target area. This paper primarily aims at describing LiVHySI, its in-orbit operations, quality, potential of the data and its first observations. The images reveal the thermospheric airglow at 630 nm to be the most prominent. These first LiVHySI observations carried out on the night of 21st April, 2011 are presented here, while the variability exhibited by the thermospheric nightglow at O(1D) 630 nm has been described in detail. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active">2</li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active">3</li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AnGeo..36..253G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AnGeo..36..253G">Mesospheric front observations by the OH airglow imager carried out at Ferraz Station on King George Island, Antarctic Peninsula, in 2011</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Giongo, Gabriel Augusto; Valentin Bageston, José; Prado Batista, Paulo; Wrasse, Cristiano Max; Dornelles Bittencourt, Gabriela; Paulino, Igo; Paes Leme, Neusa Maria; Fritts, David C.; Janches, Diego; Hocking, Wayne; Schuch, Nelson Jorge 2018-02-01 The main goals of this work are to characterize and investigate the potential wave sources of four mesospheric fronts identified in the hydroxyl near-infrared (OH-NIR) airglow images, obtained with an all-sky airglow imager installed at Comandante Ferraz Antarctic Station (EACF, as per its Portuguese acronym) located on King George Island in the Antarctic Peninsula. We identified and analyzed four mesospheric fronts in 2011 over King George Island. In addition, we investigate the atmospheric background environment between 80 and 100 km altitude and discuss the ducts and propagation conditions for these waves. For that, we used wind data obtained from a meteor radar operated at EACF and temperature data obtained from the TIMED/SABER satellite. The vertical wavenumber squared, m2, was calculated for each of the four waves. Even though no clearly defined duct (indicated by positive values of m2 sandwiched between layers above and below with m2 < 0) was found in any of the events, favorable propagation conditions for horizontal propagation of the fronts were found in three cases. In the fourth case, the wave front did not find any duct support and it appeared to dissipate near the zenith, transferring energy and momentum to the medium and, consequently, accelerating the wind in the wave propagation direction (near to south) above the OH peak (88-92 km). The likely wave sources for these four cases were investigated by using meteorological satellite images and in two cases we could find that strong instabilities were potential sources, i.e., a cyclonic activity and a large convective cloud cell. In the other two cases it was not possible to associate troposphere sources as potential candidates for the generation of such wave fronts observed in the mesosphere and secondary wave sources were attributed to these cases. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA42A..04H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA42A..04H">Optical imaging of airglow structure in equatorial plasma bubbles at radio scintillation scales</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Holmes, J. M.; Pedersen, T.; Parris, R. T.; Stephens, B.; Caton, R. G.; Dao, E. V.; Kratochvil, S.; Morton, Y.; Xu, D.; Jiao, Y.; Taylor, S.; Carrano, C. S. 2015-12-01 Imagery of optical emissions from F-region plasma is one of the few means available todetermine plasma density structure in two dimensions. However, the smallest spatial scalesobservable with this technique are typically limited not by magnification of the lens or resolutionof the detector but rather by the optical throughput of the system, which drives the integrationtime, which in turn causes smearing of the features that are typically moving at speeds of 100m/s or more. In this paper we present high spatio-temporal imagery of equatorial plasma bubbles(EPBs) from an imaging system called the Large Aperture Ionospheric Structure Imager(LAISI), which was specifically designed to capture short-integration, high-resolution images ofF-region recombination airglow at λ557.7 nm. The imager features 8-inch diameter entranceoptics comprised of a unique F/0.87 lens, combined with a monolithic 8-inch diameterinterference filter and a 2x2-inch CCD detector. The LAISI field of view is approximately 30degrees. Filtered all-sky images at common airglow wavelengths are combined with magneticfield-aligned LAISI images, GNSS scintillation, and VHF scintillation data obtained atAscension Island (7.98S, 14.41W geographic). A custom-built, multi-constellation GNSS datacollection system was employed that sampled GPS L1, L2C, L5, GLONASS L1 and L2, BeidouB1, and Galileo E1 and E5a signals. Sophisticated processing software was able to maintainlock of all signals during strong scintillation, providing unprecedented spatial observability ofL band scintillation. The smallest-resolvable scale sizes above the noise floor in the EPBs, as viewed byLAISI, are illustrated for integration times of 1, 5 and 10 seconds, with concurrentzonal irregularity drift speeds from both spaced-receiver VHF measurements and single-stationGNSS measurements of S4 and σφ. These observable optical scale sizes are placed in thecontext of those that give rise to radio scintillation in VHF and L band signals. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA42A..07R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA42A..07R">Nighttime medium scale traveling ionospheric disturbances in southern hemisphere using FORMOSAT-2/ISUAL 630.0 nm airglow images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Rajesh, P. K.; Lin, C. C. H.; Liu, T. J. Y.; Chen, A. B. C.; Hsu, R. R.; Chen, C. H.; Huba, J. D. 2017-12-01 In this work characteristics of nighttime medium-scale travelling ionospheric disturbances (MSTID) are investigated using 630.0 nm limb images by Imager of Sprites and Upper Atmospheric Lightnings (ISUAL), onboard FORMOSAT-2 satellite. The limb integrated measurements, when projected to a horizontal plane, reveal bands of intensity perturbation with distinct southwest to northeast orientation in the southern hemisphere. Airglow simulations are carried out by artificially introducing MSTID fluctuations in model electron density to confirm if such azimuthally oriented features could be identified in the ISUAL viewing geometry. Further statistical analysis shows more MSTID occurrence in solstices with peak in June-July months. The wavelengths of the observed perturbations were in the range 150-300 km. The wave fronts were oriented about 30°-50° from the east-west plane, indicating that coupled Perkins and Es-layer instability might be important in the MSTID generation. The results demonstrate that space based airglow imaging is an effective method for global investigation of MSTID events that are appropriately aligned with the viewing geometry. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..12212430O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..12212430O">First Study on the Occurrence Frequency of Equatorial Plasma Bubbles over West Africa Using an All-Sky Airglow Imager and GNSS Receivers</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Okoh, Daniel; Rabiu, Babatunde; Shiokawa, Kazuo; Otsuka, Yuichi; Segun, Bolaji; Falayi, Elijah; Onwuneme, Sylvester; Kaka, Rafiat 2017-12-01 This is the first paper that reports the occurrence frequency of equatorial plasma bubbles and their dependences of local time, season, and geomagnetic activity based on airglow imaging observations at West Africa. The all-sky imager, situated in Abuja (Geographic: 8.99°N, 7.38°E; Geomagnetic: 1.60°S), has a 180° fisheye view covering almost the entire airspace of Nigeria. Plasma bubbles are observed for 70 nights of the 147 clear-sky nights from 9 June 2015 to 31 January 2017. Differences between nighttime and daytime ROTIs were also computed as a proxy of plasma bubbles using Global Navigation Satellite Systems (GNSS) receivers within the coverage of the all-sky imager. Most plasma bubble occurrences are found during equinoxes and least occurrences during solstices. The occurrence rate of plasma bubbles was highest around local midnight and lower for hours farther away. Most of the postmidnight plasma bubbles were observed around the months of December to March, a period that coincides with the harmattan period in Nigeria. The on/off status of plasma bubble in airglow and GNSS observations were in agreement for 67.2% of the total 768 h, while we suggest several reasons responsible for the remaining 32.8% when the airglow and GNSS bubble status are inconsistent. A majority of the plasma bubbles were observed under relatively quiet geomagnetic conditions (Dst ≥ -40 and Kp ≤ 3), but there was no significant pattern observed in the occurrence rate of plasma bubbles as a function of geomagnetic activity. We suggest that geomagnetic activities could have either suppressed or promoted the occurrence of plasma bubbles. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRA..115.9315A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..115.9315A">Midnight latitude-altitude distribution of 630 nm airglow in the Asian sector measured with FORMOSAT-2/ISUAL</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Adachi, Toru; Yamaoka, Masashi; Yamamoto, Mamoru; Otsuka, Yuichi; Liu, Huixin; Hsiao, Chun-Chieh; Chen, Alfred B.; Hsu, Rue-Ron 2010-09-01 The Imager for Sprites and Upper Atmospheric Lightning (ISUAL) payload on board the FORMOSAT-2 satellite carried out the first limb imaging observation of 630 nm airglow for the purpose of studying physical processes in the F region ionosphere. For a total of 14 nights in 2006-2008, ISUAL scanned the midnight latitude-altitude distribution of 630 nm airglow in the Asian sector. On two nights of relatively active conditions (ΣKp = 26, 30+) we found several bright airglow regions, which were highly variable each night in terms of luminosity and location. In relatively quiet conditions (ΣKp = 4-20) near May/June we found two bright regions which were stably located in the midlatitude region of 40°S-10°S (50°S-20°S magnetic latitude (MLAT)) and in the equatorial region of 0°-10°N (10°S-0° MLAT). On one of the quiet nights, FORMOSAT-3/COSMIC and CHAMP simultaneously measured the plasma density in the same region where ISUAL observed airglow. The plasma density data generally show good agreement, suggesting that plasma enhancements were the primary source of these two bright airglow regions. From detailed comparison with past studies we explain that the airglow in the equatorial region was due to the midnight brightness wave produced in association with the midnight temperature maximum, while that in the midlatitude region was due to the typical plasma distribution usually formed in the midnight sector. The fact that the equatorial airglow was much brighter than the midlatitude airglow and was observed on most nights during the campaign period strongly suggests the importance of further studies on the MTM/MBW phenomenology, which is not well reproduced in the current general circulation model. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35..231A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35..231A">Zonal drift velocities of the ionospheric plasma bubbles over brazilian region using oi630nm airglow digital images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Arruda, D. C. S.; Sobral, J. H. A.; Abdu, M. A.; Castilho, V. M.; Takahashi, H. The zonal drift velocities of the ionospheric plasma bubbles over the Brazilian region are analyzed in this study that is based on OI630nm airglow digital images. These digital images were obtained by an all-sky imager system between October 1998 and August 2000, at Cachoeira Paulista (22.5°S, 45°W), a low latitude region. In this period, 138 nights of OI 630 nm airglow experiments were carried out of which 30 nights detected the ionospheric plasma bubbles. These 30 nights correspond to magnetically quiet days (ΣK_P<24+) and were grouped according approximately to their season. KEY WORDS: Imager System, Ionospheric Plasma Bubbles, Zonal drift velocities, OI630nm. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA13B..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA13B..03S">Optical Imaging Observation of the Geospace from the International Space Station by ISS-IMAP</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Saito, A.; Sakanoi, T.; Yoshikawa, I.; Yamazaki, A.; Hozumi, Y.; Perwitasari, S.; Otsuka, Y.; Yamamoto, M. 2017-12-01 Optical imaging observation of the mesosphere, thermosphere, ionosphere, and plasmasphere was carried out from the International Space Station (ISS) with ISS-IMAP (Ionosphere, Mesosphere, upper Atmosphere, and Plasmasphere mapping) mission instruments. ISS-IMAP instruments was installed on the Exposed Facility of Japanese Experiment Module of the ISS in August, 2012, and removed in August, 2015. They are two imagers, Visible-light and Infrared Spectrum Imager (VISI) and Extreme UltraViolet Imager (EUVI). VISI made imaging observations of the airglow and aurora in the nadir direction. It had two slits perpendicular to the trajectory of ISS, and the movement of ISS made the two-dimensional observation whose field-of-view width is 600km at 100km altitude. It covered the wave length range from 500nm to 900nm. The airglow of 730nm (OH, Alt. 85km), 762nm (O2, Alt. 95km), and 630nm (O, Alt. 250km) were mainly observed besides the other airglow, such as 589nm (Na) and 557 (O). EUVI made imaging observation of the resonant scattering from ions. It had two telescopes, and observed the resonant scattering of He+ in 30.4nm, and O+ in 83.4nm in the limb direction. VISI captured the airglow structures whose wavelength from 80km to 500km. The concentric wave structures were frequently observed in the mesosphere and lower thermosphere region. They are strong evidence of the vertical coupling between the lower atmosphere and the upper atmosphere by vertical propagation of the atmospheric gravity waves. The other airglow structures, such as mesospheric bores, were also detected by ISS-IMAP/VISI. The meso-scale structures in the ionosphere, such as plasma bubbles, and traveling ionospheric disturbances were also observed. EUVI revealed the longitudinal structures of He+ in the top side of the ionosphere. It was attributed to the neutral wind in the thermosphere. In the presentation, the outline and results of the ISS-IMAP's VISI and EUVI observations will be discussed. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH21C1828O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH21C1828O">Internal Gravity Wave Induced by the Queen Charlotte Event (27 October 2012, Mw 7.8): Airglow Observation and Modeling.</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Occhipinti, G.; Bablet, A.; Makela, J. J. 2015-12-01 The detection of the tsunami related internal gravity waves (IGWtsuna) by airglow camera has been recently validated by observation (Makela et al., 2011) and modeling (Occhipinti et al., 2011) in the case of the Tohoku event (11 March 2011, Mw 9.0). The airglow is measuring the photon emission at 630 nm, indirectly linked to the plasma density of O2+ (Link & Cogger, 1988) and it is commonly used to detect transient event in the ionosphere (Kelley et al., 2002, Makela et al., 2009, Miller et al., 2009). The modeling of the IGWtsuna clearly reproduced the pattern of the airglow measurement observed over Hawaii and the comparison between the observation and the modeling allows to recognize the wave form and allow to explain the IGWtsuna arriving before the tsunami wavefront at the sea level (Occhipinti et al., 2011). Approaching the Hawaiian archipelagos the tsunami propagation is slowed down (reduction of the sea depth), instead, the IGWtsuna, propagating in the atmosphere/ionosphere, conserves its speed. In this work, we present the modeling of the new airglow observation following the Queen Charlotte event (27 October 2012, Mw 7.8) that has been recently detected, proving that the technique can be generalized for smaller events. Additionally, the effect of the wind on the IGWtsuna, already evocated in the past, is included in the modeling to better reproduce the airglow observations. All ref. here @ www.ipgp.fr/~ninto </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AMT.....9.5955S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AMT.....9.5955S">High-resolution observations of small-scale gravity waves and turbulence features in the OH airglow layer</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sedlak, René; Hannawald, Patrick; Schmidt, Carsten; Wüst, Sabine; Bittner, Michael 2016-12-01 A new version of the Fast Airglow Imager (FAIM) for the detection of atmospheric waves in the OH airglow layer has been set up at the German Remote Sensing Data Center (DFD) of the German Aerospace Center (DLR) at Oberpfaffenhofen (48.09° N, 11.28° E), Germany. The spatial resolution of the instrument is 17 m pixel-1 in zenith direction with a field of view (FOV) of 11.1 km × 9.0 km at the OH layer height of ca. 87 km. Since November 2015, the system has been in operation in two different setups (zenith angles 46 and 0°) with a temporal resolution of 2.5 to 2.8 s. In a first case study we present observations of two small wave-like features that might be attributed to gravity wave instabilities. In order to spectrally analyse harmonic structures even on small spatial scales down to 550 m horizontal wavelength, we made use of the maximum entropy method (MEM) since this method exhibits an excellent wavelength resolution. MEM further allows analysing relatively short data series, which considerably helps to reduce problems such as stationarity of the underlying data series from a statistical point of view. We present an observation of the subsequent decay of well-organized wave fronts into eddies, which we tentatively interpret in terms of an indication for the onset of turbulence. Another remarkable event which demonstrates the technical capabilities of the instrument was observed during the night of 4-5 April 2016. It reveals the disintegration of a rather homogenous brightness variation into several filaments moving in different directions and with different speeds. It resembles the formation of a vortex with a horizontal axis of rotation likely related to a vertical wind shear. This case shows a notable similarity to what is expected from theoretical modelling of Kelvin-Helmholtz instabilities (KHIs). The comparatively high spatial resolution of the presented new version of the FAIM provides new insights into the structure of atmospheric wave instability and </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910058277&hterms=optics+interference&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Doptics%2Binterference','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910058277&hterms=optics+interference&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Doptics%2Binterference">Thin film interference optics for imaging the O II 834-A airglow</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Seely, John F.; Hunter, William R. 1991-01-01 Normal incidence thin film interference mirrors and filters have been designed to image the O II 834-A airglow. It is shown that MgF2 is a useful spacer material for this wavelength region. The mirrors consist of thin layers of MgF2 in combination with other materials that are chosen to reflect efficiently in a narrow band centered at 834 A. Peak reflectance of 60 percent can be obtained with a passband 200 A wide. Al/MgF2/Si and Al/MgF2/SiC interference coatings have been designed to reflect 834 A and to absorb the intense H I 1216 A airglow. An In/MgF2/In interference filter is designed to transmit 834 A and attenuate 1216 A radiation. Interference photocathode coatings for rejecting 1216 A radiation are also discussed. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSA23B..06H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSA23B..06H">Heater-induced ionization inferred from spectrometric airglow measurements</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hysell, D. L.; Miceli, R. J.; Varney, R. H.; Schlatter, N.; Huba, J. D. 2013-12-01 Spectrographic airglow measurements were made during an ionospheric modification experiment at HAARP on March 12, 2013. Artificial airglow enhancements at 427.8, 557.7, 630.0, 777.4, and 844.6 nm were observed. On the basis of these emissions and using a methodology based on the method of Backus and Gilbert [1968, 1970], we estimate the suprathermal electron population and the subsequent equilibrium electron density profile, including contributions from electron impact ionization. We find that the airglow is consistent with significant induced ionization in view of the spatial intermittency of the airglow. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.1411S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.1411S">The Martian airglow: observations by Mars Express and kinetic modelling</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Simon, Cyril; Leblanc, François; Gronoff, Guillaume; Witasse, Olivier; Lilensten, Jean; Barthelemy, Mathieu; Bertaux, Jean-Loup The photoemissions on Mars are the result of physical chemistry reactions in the upper atmo-sphere that depend on the planet's plasma environment. They arise on the dayside from UV photo-excitation (Barth et al., 1971) and on the nightside from chemical reactions and electron precipitation above regions of strong crustal magnetism (Bertaux et al., 2005). The physics of airglow generation at Mars is discussed both in terms of observations (satellites) and models (especially transport codes). A review of observations made by SPICAM, the UV spectrometer onboard Mars Express, is first presented. The Cameron bands of CO(a - X), the CO+ (A - X) 2 doublet at 289.0 nm and the trans-auroral line of OI (297.2 nm) are mainly seen on the dayside. On the nightside both Cameron emissions and NO(C - X and A - X) emissions are present. In a second step, an updated airglow model has been developed and compared to the latest SPICAM data. Several interesting implications are highlighted regarding neutral atmosphere variations for the dayglow (Simon et al., 2009) and electron precipitation mechanisms at the origin of the auroral intensities measured by SPICAM in conjunction with the particle detector ASPERA and the radar MARSIS. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780004642','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780004642">A rocket-borne airglow photometer</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Paarmann, L. D.; Smith, L. G. 1977-01-01 The design of a rocket-borne photometer to measure the airglow emission of ionized molecular nitrogen in the 391.4 nm band is presented. This airglow is a well known and often observed phenomenon of auroras, where the principal source of ionization is energetic electrons. It is believed that at some midlatitude locations energetic electrons are also a source of nighttime ionization in the E region of the ionosphere. If this is so, then significant levels of 391.4 nm airglow should be present. The intensity of this airglow will be measured in a rocket payload which also contains instrumentation to measured in a rocket payload which also contains instrumentation to measure energetic electron differential flux and the ambient electron density. An intercomparison of the 3 experiments in a nightime launch will allow a test of the importance of energetic electrons as a nighttime source of ionization in the upper E region. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.2038H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.2038H">Heater-induced ionization inferred from spectrometric airglow measurements</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hysell, D. L.; Miceli, R. J.; Kendall, E. A.; Schlatter, N. M.; Varney, R. H.; Watkins, B. J.; Pedersen, T. R.; Bernhardt, P. A.; Huba, J. D. 2014-03-01 Spectrographic airglow measurements were made during an ionospheric modification experiment at High Frequency Active Auroral Research Program on 12 March 2013. Artificial airglow enhancements at 427.8, 557.7, 630.0, 777.4, and 844.6 nm were observed. On the basis of these emissions and using a methodology based on the method of Backus and Gilbert (1968, 1970), we estimate the suprathermal electron population and the subsequent equilibrium electron density profile, including contributions from electron impact ionization. We find that the airglow is consistent with heater-induced ionization in view of the spatial intermittency of the airglow. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA12A..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA12A..03S">Recent observations of traveling ionospheric disturbances and plasma bubbles using Optical Mesosphere Thermosphere Imagers in Asian and African sectors</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Shiokawa, K.; Otsuka, Y.; Tsuchiya, S.; Moral, A. C.; Okoh, D. 2017-12-01 We review recent observational results of medium-scale traveling ionospheric disturbances (MSTIDs) and equatorial plasma bubbles obtained by using airglow imagers and Fabry-Perot interferometers of the Optical Mesosphere Thermosphere Imagers (OMTIs) at Asian and African sectors. The OMTIs contains 20 airglow imagers and 5 Fabry-Perot interferometers (FPIs) at Canada, USA (Alaska), Russia, Finland, Norway, Iceland, Japan, Thailand, Indonesia, Australia, and Nigeria (http://stdb2.isee.nagoya-u.ac.jp/omti/). The 3-dimentional Fast Fourier Transformation of airglow images makes it possible to analyze 16-year airglow images obtained at Shigaraki (34.8N) and Rikubetsu (43.5N), Japan, to obtain phase velocity spectra of gravity waves and MSTIDs. The MSTIDs spectra show clear southwestward preference of propagation and minor northeastward propagation over Japan. We also found clear negative correlation between MSTID power and solar F10.7 flux, indicating that MSTIDs becomes more active during solar quiet time. This fact suggest the control of ionospheric Perkins and E-F coupling instabilities by solar activities. Three TIDs in airglow images over Indonesia, including midnight brightness waves (MBWs), were compared with CHAMP-satellite overpass to investigate neutral density variations in the thermosphere associated with the TIDs. We found clear correspondence in variations between the airglow intensities and neutral densities, suggesting that the observed TIDs over the equatorial region is caused by gravity waves. We also compare average thermospheric temperatures measured by the four FPIs for 3-4 years with the MSIS90E and GAIA models. The comparison shows that GAIA generally shows better fitting than the MSIS90E, but at the equatorial stations, GAIA tends to fail to reproduce the FPI temperature, probably due to ambiguity of location of the midnight temperature maximum. We also made statistics of plasma bubble occurrence using airglow imager and GNSS receiver at Abuja (9 </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.1919F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.1919F">Very high resolution observations of waves in the OH airglow at low latitudes.</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Franzen, Christoph; Espy, Patrick J.; Hibbins, Robert E.; Djupvik, Amanda A. 2017-04-01 Vibrationally excited hydroxyl (OH) is produced in the mesosphere by the reaction of atomic hydrogen and ozone. This excited OH radiates a strong, near-infrared airglow emission in a thin ( 8 km thick) layer near 87 km. In the past, remote sensing of perturbations in the OH Meinel airglow has often been used to observe gravity, tidal and planetary waves travelling through this region. However, information on the highest frequency gravity waves is often limited by the temporal and spatial resolution of the available observations. In an effort to expand the wave scales present near the mesopause, we present a series of observations of the OH Meinel (9,7) transition that were executed with the Nordic Optical Telescope on La Palma (18°W, 29°N). These measurements are taken with a 10 s integration time (24 s repetition rate), and the spatial resolution at 87 km is as small as 10 m, allowing us to quantify the transition between the gravity and acoustic wave domains in the mesosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9910E..1BR','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9910E..1BR">Measurements of airglow on Maunakea at Gemini Observatory</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Roth, Katherine C.; Smith, Adam; Stephens, Andrew; Smirnova, Olesja 2016-07-01 Gemini Observatory on Maunakea has been collecting optical and infrared science data for almost 15 years. We have begun a program to analyze imaging data from two of the original facility instruments, GMOS and NIRI, in order to measure sky brightness levels in multiple infrared and optical broad-band filters. The present work includes data from mid-2016 back through late-2008. We present measured background levels as a function of several operational quantities (e.g. moon phase, hours from twilight, season). We find that airglow is a significant contributor to background levels in several filters. Gemini is primarily a queue scheduled telescope, with observations being optimally executed in order to provide the most efficient use of telescope time. We find that while most parameters are well-understood, the atmospheric airglow remains challenging to predict. This makes it difficult to schedule observations which require dark skies in these filters, and we suggest improvements to ensure data quality. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JASTP.164..116L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JASTP.164..116L">Semidiurnal tidal activity of the middle atmosphere at mid-latitudes derived from O2 atmospheric and OH(6-2) airglow SATI observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> López-González, M. J.; Rodríguez, E.; García-Comas, M.; López-Puertas, M.; Olivares, I.; Ruiz-Bueno, J. A.; Shepherd, M. G.; Shepherd, G. G.; Sargoytchev, S. 2017-11-01 In this paper, we investigate the tidal activity in the mesosphere and lower thermosphere region at 370N using OH Meinel and O2 atmospheric airglow observations from 1998 to 2015. The observations were taken with a Spectral Airglow Temperature Imager (SATI) installed at Sierra Nevada Observatory (SNO) (37.060N, 3.380W) at 2900 m height. From these observations a seasonal dependence of the amplitudes of the semidiurnal tide is inferred. The maximum tidal amplitude occurs in winter and the minimum in summer. The vertically averaged rotational temperatures and vertically integrated volume emission rate (rotational temperatures and intensities here in after), from the O2 atmospheric band measurements and the rotational temperature derived from OH Meinel band measurements reach the maximum amplitude about 1-4 h after midnight during almost all the year except in August-September where the maximum is found 2-4 h earlier. The amplitude of the tide in the OH intensity reaches the minimum near midnight in midwinter, then it is progressively delayed until 4:00 LT in August-September, and from there on it moves again forward towards midnight. The mean Krassovsky numbers for OH and O2 emissions are 5.9 ±1.8 and 5.6 ±1.0, respectively, with negative Krassovsky phases for almost all the year, indicating an upward energy transport. The mean vertical wavelengths for the vertical tidal propagation derived from OH and O2 emissions are 35 ±20 km and 33 ±18 km, respectively. The vertical wavelengths together with the phase shift in the temperature derived from both airglow emissions indicate that these airglow emission layers are separated by 7 ±3 km, on average. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.3748L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.3748L">Characteristics of ripple structures revealed in OH airglow images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Li, Jing; Li, Tao; Dou, Xiankang; Fang, Xin; Cao, Bing; She, Chiao-Yao; Nakamura, Takuji; Manson, Alan; Meek, Chris; Thorsen, Denise 2017-03-01 Small-scale ripple structures observed in OH airglow images are most likely induced by either dynamic instability due to large wind shear or convective instability due to superadiabatic lapse rate. Using the data set taken in the mesopause region with an OH all-sky imager at Yucca Ridge Field Station, Colorado (40.7°N, 104.9°W), from September 2003 to December 2005, we study the characteristics and seasonal variations of ripple structures. By analyzing the simultaneous background wind and temperature observed by the nearby sodium temperature/wind lidar at Fort Collins, Colorado (40.6°N, 105°W), and a nearby medium-frequency radar at Platteville, Colorado (40.2°N, 105.8°W), we are able to statistically study the possible relation between ripples and the background atmosphere conditions. Characteristics and seasonal variations of ripples are presented in detail in this study. The occurrence frequency of ripples exhibits clear seasonal variability, with peak in autumn. The occurrence of ripples shows a local time dependence, which is most likely associated with the solar tides. The lifetime and spatial scale of these ripples are typically 5-20 min and 5-10 km, respectively, and most of the ripples move preferentially either southward or northward. However, more than half of the observed ripples do not advect with background flow; they have higher Richardson numbers than those ripples that advect with background flow. It is possible that they are not instability features but wave structures that are hard to be distinguished from the real instability features. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880042140&hterms=Abreu&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DAbreu%252C%2Bc.','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880042140&hterms=Abreu&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DAbreu%252C%2Bc.">The Visible Airglow Experiment - A review</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Hays, Paul B.; Abreu, Vincent J.; Solomon, Stanley C.; Yee, Jeng-Hwa 1988-01-01 Contributions of the Visible Airglow Experiment (VAE) to the understanding of various airglow and auroral processes are reviewed. The impact of instrumental design and operation on the observations is discussed, and emphasis is placed on the relationship between observations and inversion for optical measurements of light emissions from a diffuse medium. VAE data are used to explain the physical mechanisms responsible for the production and destruction of excited species including O(+)(1P), O(1D), O(1S), N(2D), and Mg(+)2P1/2. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active">3</li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active">4</li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850029402&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850029402&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight">Rocket observations of the ultraviolet airglow during morning twilight</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Cebula, R. P.; Feldman, P. D. 1984-01-01 Rocket-borne (Astrobee) UV measurements were made of the terrestrial airglow at morning twilight from 82 and 90 deg zenith angles at altitudes of 90 and 246 km in September 1979. Data were acquired on the NO gamma and delta bands, the 2470 A O II, 1356 A and the 1304 A O I lines, the Lyman-Berge-Hopfield N2 and the Herzberg 02 lines. The zodiacal contribution was substracted to obtain pure airglow data. Spectral analyses supported a larger nighttime decrease of N(4S) than for NO, the latter being in diffusive equilibrium above 190 km altitude. The NO gamma band was directly related to the thermospheric N(4S) contribution, the latter having a density of 2-8 million/cu cm at 200 km. Finally, self-consistent photoionization and photoelectron impact ionization models were derived for the atomic and ionic oxygen emissions. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720021779','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720021779">The equatorial airglow and the ionospheric geomagnetic anomaly</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Chandra, S.; Reed, E. I.; Troy, B. E., Jr.; Blamont, J. E. 1972-01-01 OGO D observations of OI (6300A) emissions reveal a global pattern in the equatorial airglow undetected from the ground-based observations. The post sunset emission rate of OI is generally asymmetrical with respect to the geomagnetic equator and shows no apparent correlation with the ultraviolet airglow (OI 1304 and 1356A) and F region electron density measured simultaneously from the same spacecraft. Both the ultraviolet airglow and the ion density measured in the altitude region of 450 km follow similar latitudinal variations and exhibit properties of the equatorial ionospheric anomaly. The asymmetry in OI emission can be attributed to the asymmetry in the height of the F 2 maximum inferred from the height of the maximum emission. From correlative studies of the airglow and the ionospheric measurements, the mechanisms for the ultraviolet and the 6300A emission are discussed in terms of the processes involving radiative and dissociative recombinations. A relationship between molecular oxygen density and the integrated OI emission rate is derived and the feasibility of using this relationship for estimating O2 density is discussed. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930018294','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930018294">An assessment of twilight airglow inversion procedures using atmosphere explorer observations</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Mcdade, I. C.; Sharp, W. E. 1993-01-01 The aim of this research project was to test and truth some recently developed methods for recovering thermospheric oxygen atom densities and thermospheric temperatures from ground-based observations of the 7320 A O(+)((sup 2)D - (sup 2)P) twilight air glow emission. The research plan was to use twilight observations made by the Visible Airglow Experiment (VAE) on the Atmosphere Explorer 'E' satellite as proxy ground based twilight observations. These observations were to be processed using the twilight inversion procedures, and the recovered oxygen atom densities and thermospheric temperatures were then to be examined to see how they compared with the densities and temperatures that were measured by the Open Source Mass Spectrometer and the Neutral Atmosphere Temperature Experiment on the satellite. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AnGeo..36..705N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AnGeo..36..705N">Determination of gravity wave parameters in the airglow combining photometer and imager data</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Nyassor, Prosper K.; Arlen Buriti, Ricardo; Paulino, Igo; Medeiros, Amauri F.; Takahashi, Hisao; Wrasse, Cristiano M.; Gobbi, Delano 2018-05-01 Mesospheric airglow measurements of two or three layers were used to characterize both vertical and horizontal parameters of gravity waves. The data set was acquired coincidentally from a multi-channel filter (Multi-3) photometer and an all-sky imager located at São João do Cariri (7.4° S, 36.5° W) in the equatorial region from 2001 to 2007. Using a least-square fitting and wavelet analysis technique, the phase and amplitude of each observed wave were determined, as well as the amplitude growth. Using the dispersion relation of gravity waves, the vertical and horizontal wavelengths were estimated and compared to the horizontal wavelength obtained from the keogram analysis of the images observed by an all-sky imager. The results show that both horizontal and vertical wavelengths, obtained from the dispersion relation and keogram analysis, agree very well for the waves observed on the nights of 14 October and 18 December 2006. The determined parameters showed that the observed wave on the night of 18 December 2006 had a period of ˜ 43.8 ± 2.19 min, with the horizontal wavelength of 235.66 ± 11.78 km having a downward phase propagation, whereas that of 14 October 2006 propagated with a period of ˜ 36.00 ± 1.80 min with a horizontal wavelength of ˜ 195 ± 9.80 km, and with an upward phase propagation. The observation of a wave taken by a photometer and an all-sky imager allowed us to conclude that the same wave could be observed by both instruments, permitting the investigation of the two-dimensional wave parameter. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSA21B..07W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSA21B..07W">An Intense Traveling Airglow Front in the Upper Mesosphere-Lower Thermosphere with Characteristic of a Turbulent Bore Observed over Alice Springs, Australia</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Walterscheid, R. L.; Hecht, J. H.; Hickey, M. P.; Gelinas, L. J.; Vincent, R. A.; Reid, I. M.; Woithe, J. 2010-12-01 The Aerospace Corporation’s Nightglow Imager observed a large step-function change in airglow in the form of a traveling front in the OH and O2 airglow emissions over Alice Springs Australia on February 2, 2003. The front exhibited a stepwise increase of nearly a factor two in the OH brightness and a stepwise decrease in the O2 brightness. The change in brightness in each layer was associated with a strong leading disturbance followed by a train of weak barely visible waves. The OH airglow brightness behind the front was the brightness night for 02 at Alice Springs that we have measured in seven years of observations. The OH brightness was among the five brightest. The event was associated with a strong phase-locked two-day wave (TDW).We have analyzed the stability conditions for the upper mesosphere and lower thermosphere and found that the airglow layers were found in a region of strong ducting. The thermal structure was obtained from combining data from the SABER instrument on the TIMED satellite and the NRLMSISE-00 model. The wind profile was obtained by combining the HWM07 model and MF radar winds from Buckland Park Australia. We found that the TDW-disturbed profile was significantly more effective in supporting a high degree of ducting than a profile based only on HWM07 winds. Dramatic wall events have been interpreted as manifestations of undular bores (e.g., Smith et al. [2003]). Undular bores are nonlinear high Froude number events that must generate an ever increasing train of waves to carry the excess energy away from the bore front. Only a very weak wave train behind the initial disturbance was seen for the Alice Springs event. The form of the amplitude ordering was not typical of a nonlinear wave train. Therefore a bore interpretation requires another means of energy dissipation, namely turbulent dissipation. We suggest that a reasonable interpretation of the observed event is a turbulent bore. We are unaware of any previous event having </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910050764&hterms=1085&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231085','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910050764&hterms=1085&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231085">Nitrogen airglow sources - Comparison of Triton, Titan, and earth</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Strobel, Darrell F.; Meier, R. R.; Summers, Michael E.; Strickland, Douglas J. 1991-01-01 The individual contributions of direct solar excitation, photoelectron excitation, and magnetospheric electron excitation of Triton and Titan airglow observed by the Voyager Ultraviolet Spectrometer (UVS) are quantified. The principal spectral features of Triton's airglow are shown to be consistent with precipitation of magnetospheric electrons with power dissipation about 500 million W. Solar excitation rates of the dominant N2 and N(+) emission features are factors of 2-7 weaker than magnetospheric electron excitation. On Titan, the calculated disk center and bright limb N(+) 1085 A intensities due to solar excitation agree with observed values, while the 970 A feature is mostly N21 c5 band emission. The calculated LBH intensity by photoelectrons suggests that magnetospheric electrons play a minor role in Titan's UV airglow. On earth, solar/photoelectron excitation explains the observed N(+) 1085 A and LBH intensites and accounts for only 40 percent of the N(+) 916 A intensity. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010DPS....42.3625S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010DPS....42.3625S">The Production of Titan's Ultraviolet Nitrogen Airglow</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Stevens, Michael H.; Gustin, J.; Ajello, J. M.; Evans, J. S.; Meier, R. R.; Stewart, A. I. F.; Esposito, L. W.; McClintock, W. E.; Stephan, A. W. 2010-10-01 The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed Titan's dayside limb on 22 June, 2009, obtaining high quality extreme ultraviolet (EUV) and far ultraviolet (FUV) spectra from a distance of only 60,000 km (23 Titan radii). The observations reveal the same EUV and FUV emissions arising from photoelectron excitation and photofragmentation of molecular nitrogen (N2) on Earth but with the altitude of peak emission much higher on Titan near 1000 km altitude. In the EUV, emission bands from the photoelectron excited N2 Carroll-Yoshino c4'-X system and N I and N II multiplets arising from photofragmentation of N2 dominate, with no detectable c4'(0,0) emission near 958 Å, contrary to many interpretations of the lower resolution Voyager 1 Ultraviolet Spectrometer data. The FUV is dominated by emission bands from the N2 Lyman-Birge-Hopfield a-X system and additional N I multiplets. We also identify several N2 Vegard-Kaplan A-X bands between 1500-1900 Å, two of which are located near 1561 and 1657 Å where C I multiplets were previously identified from a separate UVIS disk observation. We compare these limb emissions to predictions from a terrestrial airglow model adapted to Titan that uses a solar spectrum appropriate for these June, 2009 observations. Volume production rates and limb radiances are calculated, including extinction by methane and allowance for multiple scattering within the readily excited c4'(0,v') system, and compared to UVIS observations. We find that for these airglow data only emissions arising from processes involving N2 are present. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRA..11510326H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..11510326H">Further investigations of lightning-induced transient emissions in the OH airglow layer</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Huang, Tai-Yin; Kuo, C. L.; Chiang, C. Y.; Chen, A. B.; Su, H. T.; Hsu, R. R. 2010-10-01 A previous study of lightning-induced transient emissions in and below the OH airglow layer using observations by the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) CCD camera onboard the FORMOSAT-II satellite showed that intensity enhancements occurred more frequently in the OH airglow layer. Here we show the results of new observations made in December 2009 and January 2010 using a narrowband 630 nm filter and spectrophotometer and present further analysis. We estimated the N21P intensity enhancements to be ˜65% and 53% of the total intensity enhancements for the two events we analyzed using ISUAL and the spectrophotometer data in conjunction with a model for emissions of light and VLF perturbations from electromagnetic pulse sources (elves). Our analysis indicates that there is still somewhat considerable intensity enhancement (˜1.25 kR) unaccounted for after the N21P contribution has been removed. Our study suggests that there might be OH emissions in elves and that OH species might also be involved in the lightning-induced process and contribute to the intensity enhancements that we observed. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT........82A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT........82A">Airglow studies using observations made with the GLO instrument on the Space Shuttle</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Alfaro Suzan, Ana Luisa 2009-12-01 Our understanding of Earth's upper atmosphere has advanced tremendously over the last few decades due to our enhanced capacity for making remote observations from space. Space based observations of Earth's daytime and nighttime airglow emissions are very good examples of such enhancements to our knowledge. The terrestrial nighttime airglow, or nightglow, is barely discernible to the naked eye as viewed from Earth's surface. However, it is clearly visible from space - as most astronauts have been amazed to report. The nightglow consists of emissions of ultraviolet, visible and near-infrared radiation from electronically excited oxygen molecules and atoms and vibrationally excited OH molecules. It mostly emanates from a 10 km thick layer located about 100 km above Earth's surface. Various photochemical models have been proposed to explain the production of the emitting species. In this study some unique observations of Earth's nightglow made with the GLO instrument on NASA's Space Shuttle, are analyzed to assess the proposed excitation models. Previous analyses of these observations by Broadfoot and Gardner (2001), performed using a 1-D inversion technique, have indicated significant spatial structures and have raised serious questions about the proposed nightglow excitation models. However, the observation of such strong spatial structures calls into serious question the appropriateness of the adopted 1-D inversion technique and, therefore, the validity of the conclusions. In this study a more rigorous 2-D tomographic inversion technique is developed and applied to the available GLO data to determine if some of the apparent discrepancies can be explained by the limitations of the previously applied 1-D inversion approach. The results of this study still reveal some potentially serious inadequacies in the proposed photochemical models. However, alternative explanations for the discrepancies between the GLO observations and the model expectations are suggested. These </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18360466','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18360466">Three-channel imaging fabry-perot interferometer for measurement of mid-latitude airglow.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Shiokawa, K; Kadota, T; Ejiri, M K; Otsuka, Y; Katoh, Y; Satoh, M; Ogawa, T 2001-08-20 We have developed a three-channel imaging Fabry-Perot interferometer with which to measure atmospheric wind and temperature in the mesosphere and thermosphere through nocturnal airglow emissions. The interferometer measures two-dimensional wind and temperature for wavelengths of 630.0 nm (OI, altitude, 200-300 km), 557.7 nm (OI, 96 km), and 839.9 nm (OH, 86 km) simultaneously with a time resolution of 20 min, using three cooled CCD detectors with liquid-N(2) Dewars. Because we found that the CCD sensor moves as a result of changes in the level of liquid N(2) in the Dewars, the cooling system has been replaced by thermoelectric coolers. The fringe drift that is due to changes in temperature of the etalon is monitored with a frequency-stabilized He-Ne laser. We also describe a data-reduction scheme for calculating wind and temperature from the observed fringes. The system is fully automated and has been in operation since June 1999 at the Shigaraki Observatory (34.8N, 136.1E), Shiga, Japan. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20171208_Archive_e001596.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20171208_Archive_e001596.html">Waves in Airglow</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2017-12-08 In April 2012, waves in Earth’s “airglow” spread across the nighttime skies of northern Texas like ripples in a pond. In this case, the waves were provoked by a massive thunderstorm. Airglow is a layer of nighttime light emissions caused by chemical reactions high in Earth’s atmosphere. A variety of reactions involving oxygen, sodium, ozone and nitrogen result in the production of a very faint amount of light. In fact, it’s approximately one billion times fainter than sunlight (~10-11 to 10-9 W·cm-2· sr-1). This chemiluminescence is similar to the chemical reactions that light up a glow stick or glow-in-the-dark silly putty. The “day-night band,” of the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured these glowing ripples in the night sky on April 15, 2012 (top image). The day-night band detects lights over a range of wavelengths from green to near-infrared and uses highly sensitive electronics to observe low light signals. (The absolute minimum signals detectable are at the levels of nightglow emission.) The lower image shows the thunderstorm as observed by a thermal infrared band on VIIRS. This thermal band, which is sensitive only to heat emissions (cold clouds appear white), is not sensitive to the subtle visible-light wave structures seen by the day-night band. Technically speaking, airglow occurs at all times. During the day it is called “dayglow,” at twilight “twilightglow,” and at night “nightglow.” There are slightly different processes taking place in each case, but in the image above the source of light is nightglow. The strongest nightglow emissions are mostly constrained to a relatively thin layer of atmosphere between 85 and 95 kilometers (53 and 60 miles) above the Earth’s surface. Little emission occurs below this layer since there’s a higher concentration of molecules, allowing for dissipation of chemical energy via collisions rather than light production. Likewise, little </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016STP.....2c.106M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016STP.....2c.106M">Night airglow in RGB mode</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mikhalev, Aleksandr; Podlesny, Stepan; Stoeva, Penka 2016-09-01 To study dynamics of the upper atmosphere, we consider results of the night sky photometry, using a color CCD camera and taking into account the night airglow and features of its spectral composition. We use night airglow observations for 2010-2015, which have been obtained at the ISTP SB RAS Geophysical Observatory (52° N, 103° E) by the camera with KODAK KAI-11002 CCD sensor. We estimate the average brightness of the night sky in R, G, B channels of the color camera for eastern Siberia with typical values ranging from ~0.008 to 0.01 erg*cm-2*s-1. Besides, we determine seasonal variations in the night sky luminosities in R, G, B channels of the color camera. In these channels, luminosities decrease in spring, increase in autumn, and have a pronounced summer maximum, which can be explained by scattered light and is associated with the location of the Geophysical Observatory. We consider geophysical phenomena with their optical effects in R, G, B channels of the color camera. For some geophysical phenomena (geomagnetic storms, sudden stratospheric warmings), we demonstrate the possibility of the quantitative relationship between enhanced signals in R and G channels and increases in intensities of discrete 557.7 and 630 nm emissions, which are predominant in the airglow spectrum. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.8770T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.8770T">Sixteen year variation of horizontal phase velocity and propagation direction of mesospheric and thermospheric waves in airglow images at Shigaraki, Japan</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Takeo, D.; Shiokawa, K.; Fujinami, H.; Otsuka, Y.; Matsuda, T. S.; Ejiri, M. K.; Nakamura, T.; Yamamoto, M. 2017-08-01 We analyzed the horizontal phase velocity of gravity waves and medium-scale traveling ionospheric disturbances (MSTIDs) by using the three-dimensional fast Fourier transform method developed by Matsuda et al. (2014) for 557.7 nm (altitude: 90-100 km) and 630.0 nm (altitude: 200-300 km) airglow images obtained at Shigaraki MU Observatory (34.8°N, 136.1°E, dip angle: 49°) over ˜16 years from 16 March 1999 to 20 February 2015. The analysis of 557.7 nm airglow images shows clear seasonal variation of the propagation direction of gravity waves in the mesopause region. In spring, summer, fall, and winter, the peak directions are northeastward, northeastward, northwestward, and southwestward, respectively. The difference in east-west propagation direction between summer and winter is probably caused by the wind filtering effect due to the zonal mesospheric jet. Comparison with tropospheric reanalysis data shows that the difference in north-south propagation direction between summer and winter is caused by differences in the latitudinal location of wave sources due to convective activity in the troposphere relative to Shigaraki. The analysis of 630.0 nm airglow images shows that the propagation direction of MSTIDs is mainly southwestward with a minor northeastward component throughout the 16 years. A clear negative correlation is seen between the yearly power spectral density of MSTIDs and F10.7 solar flux. This negative correlation with solar activity may be explained by the linear growth rate of the Perkins instability and secondary wave generation of gravity waves in the thermosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM41A2219S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM41A2219S">Effect of severe geomagnetic disturbances on the atomic oxygen airglow emissions</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sunil Krishna, M.; Bag, T. 2013-12-01 The atomic oxygen greenline (557.7nm) and redline emission (630.0 nm) are the most readily observed and prominent lines in the nightglow. These emissions can be used as precursors for a variety of physical and chemical processes that occur in the upper mesosphere and lower thermosphere. There are a multitude of effects of space weather on the Earth's atmosphere. The decay of ring current is a very important parameter which can induce variation in the densities of few important species in the atmosphere which are of airglow interest. The connection of variation of airglow emissions with the extreme space weather conditions is not very well established. In the present study, severe geomagnetic storms and their effect on the airglow emissions such as 557.7 nm and 630.0 nm emissions is studied. This study is primarily based on photochemical models with the necessary input obtained from a combination of experimental observations and empirical models. We have tried to understand the effect of severe space weather conditions on few very important airglow emissions in terms of volume emission rates, change in the peak emission height. Based on the variation an attempt has been made to understand the cause of the variation and further to link the variations in the ring current to the airglow chemistry. The study presents the results of calculations performed for the most severe geomagnetic storms occurred over the recent past because of variety of causes on Sun. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.7834S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.7834S">Global modeling of thermospheric airglow in the far ultraviolet</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Solomon, Stanley C. 2017-07-01 The Global Airglow (GLOW) model has been updated and extended to calculate thermospheric emissions in the far ultraviolet, including sources from daytime photoelectron-driven processes, nighttime recombination radiation, and auroral excitation. It can be run using inputs from empirical models of the neutral atmosphere and ionosphere or from numerical general circulation models of the coupled ionosphere-thermosphere system. It uses a solar flux module, photoelectron generation routine, and the Nagy-Banks two-stream electron transport algorithm to simultaneously handle energetic electron distributions from photon and auroral electron sources. It contains an ion-neutral chemistry module that calculates excited and ionized species densities and the resulting airglow volume emission rates. This paper describes the inputs, algorithms, and code structure of the model and demonstrates example outputs for daytime and auroral cases. Simulations of far ultraviolet emissions by the atomic oxygen doublet at 135.6 nm and the molecular nitrogen Lyman-Birge-Hopfield bands, as viewed from geostationary orbit, are shown, and model calculations are compared to limb-scan observations by the Global Ultraviolet Imager on the TIMED satellite. The GLOW model code is provided to the community through an open-source academic research license. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994AdSpR..14..177K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994AdSpR..14..177K">Moon based global field airglow: For Artemis or any common Lunar Lander</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kozlowski, R. W. H.; Sprague, A. L.; Sandel, B. R.; Hunten, D. M.; Broadfoot, A. L. 1994-06-01 An inexpensive, small mass, airglow experiment consisting of a suite of airglow detectors is planned for one or more lunar landers. Solid state detectors measuring light through narrow band filters or concave gratings can integrate emissions from lunar atmospheric constituents and store the information for relay to earth when convenient. The proposed instrument is a simplified version of the Shuttle-borne Arizona Imager-Spectrograph. These zenith and near horizon viewing detectors may allow us to monitor fluctuations in atomic species of oxygen, calcium, sodium, potassium, argon, and neon and OH, if present. This choice of observations would monitor outgassing from the interior (Ar), meteoritic dust flux (Na, K) solar wind sputtering (O, Ca), and outgassing from the surface (implanted Ne, Na, K). A global network could be inexpensively deployed aboard landers carrying a variety of other selenographic instrumentation. Powered by solar cells such a field network will return data applicable to a wide variety of interplanetary medium and solar-lunar interaction problems. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JASTP..93...70P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JASTP..93...70P">Statistical analysis of infrasound signatures in airglow observations: Indications for acoustic resonance</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Pilger, Christoph; Schmidt, Carsten; Bittner, Michael 2013-02-01 The detection of infrasonic signals in temperature time series of the mesopause altitude region (at about 80-100 km) is performed at the German Remote Sensing Data Center of the German Aerospace Center (DLR-DFD) using GRIPS instrumentation (GRound-based Infrared P-branch Spectrometers). Mesopause temperature values with a temporal resolution of up to 10 s are derived from the observation of nocturnal airglow emissions and permit the identification of signals within the long-period infrasound range.Spectral intensities of wave signatures with periods between 2.5 and 10 min are estimated applying the wavelet analysis technique to one minute mean temperature values. Selected events as well as the statistical distribution of 40 months of observation are presented and discussed with respect to resonant modes of the atmosphere. The mechanism of acoustic resonance generated by strong infrasonic sources is a potential explanation of distinct features with periods between 3 and 5 min observed in the dataset. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA33A2573T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA33A2573T">Statistical analysis of 16-year phase velocity distribution of mesospheric and ionospheric waves in airglow images: Comparison between Rikubetsu and Shigaraki, Japan</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tsuchiya, S.; Shiokawa, K.; Fujinami, H.; Otsuka, Y.; Nakamura, T.; Yamamoto, M. 2017-12-01 A new spectral analysis technique has been developed to obtain power spectra in the horizontal phase velocity by using the 3-D Fast Fourier Transform [Matsuda et al., JGR, 2014]. Takeo et al. (JGR, 2017) studied spectral parameters of atmospheric gravity waves (AGWs) in the mesopause region and medium-scale traveling ionospheric disturbances (MSTIDs) in the thermosphere over 16 years by using airglow images at wavelengths of 557.7 nm (emission altitudes: 90-100 km) and 630.0 nm (200-300 km) obtained at Shigaraki (34.8N, 136.1E), Japan. In this study, we have applied the same spectral analysis technique to the 557.7 nm and 630.0-nm airglow images obtained at Rikubetsu (43.5N, 143.8E), Japan, for 16 years from 1999 to 2014. We compared spectral features of AGWs and MSTIDs over 16 years observed at Shigaraki and Rikubetsu, which are separated by 1,174 km. The propagation direction of mesospheric AGWs seen in 557.7-nm airglow images is northeastward in summer and southwestward in winter at both Shigaraki and Rikubetsu, probably due to wind filtering of these waves by the mesospheric jet. In winter, the propagation direction of AGWs gradually shifted from southwestward to northwestward as time progresses from evening to morning at both stations. We suggest that this local-time shift of propagation direction can also be explained by the wind filtering effect. The propagation direction of AGWs changed from southwestward to northeastward at Rikubetsu on the day of the reversal of eastward zonal wind at 60N and 10 hPa (about 35 km in altitude) by the stratospheric sudden warming (SSW), while such a SSW-associated change was not identified at Shigaraki, indicating that the effect of SSW wind reversal reached only to the Rikubetsu latitudes. For MSTIDs, there is a negative correlation between yearly variation of powers spectral density and F10.7 flux and propagation direction is southwestward in all season at both Shigaraki and Rikubetsu. This negative correlation can be </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRA..123.1593X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRA..123.1593X">Longitudinal Thin Structure of Equatorial Plasma Depletions Coincidently Observed by Swarm Constellation and all-Sky Imager</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Xiong, Chao; Xu, Jiyao; Wu, Kun; Yuan, Wei 2018-02-01 The lower pair satellites of Swarm mission, flying side-by-side and separated by 1.4° in longitude (about 150 km), usually observed equatorial plasma depletions (EPDs) showing quite different structures, and sometime even only one satellite observed EPD. In this study, we provided 6-h continuous observations of EPDs on the night of 23-24 September 2014, from an all-sky imager located at Fuke (geographic:19.5°N,109.1°E), south of China. From the airglow images the EPDs were found with longitudinal extensions of about 50 km and all tilted from northwest to southeast direction. We further checked the in situ electron density simultaneously measured by the Swarm lower pair satellites and found the differences of Swarm in situ electron densities explained well by the longitudinally thin structure of EPDs observed from the all-sky imager. During later periods the bifurcation and merging were observed by the airglow images, and it was the first time to report both processes in the evolution of one EPD. The bifurcation was first observed at the higher-latitude part, and then observed at lower latitudes of EPD. The subbranches generated through bifurcation showed even thinner longitudinal extension of about 20-30 km, and later the subbranches started to merge with each other, forming a really complicated mesh of depleted regions. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4920902P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4920902P">Monitoring Saturn's Upper Atmosphere Density Variations Using Helium 584 Airglow</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Parkinson, Chris 2017-10-01 The study of He 584 Å brightnesses is interesting as the EUV (Extreme UltraViolet) planetary airglow have the potential to yield useful information about mixing and other important parameters in its thermosphere. Resonance scattering of sunlight by He atoms is the principal source of the planetary emission of He 585 Å. The principal parameter involved in determining the He 584 Å albedo are the He volume mixing ratio, f_He, well below the homopause. Our main science objective is to estimate the helium mixing ratio in the lower atmosphere. Specifically, He emissions come from above the homopause where optical depth trau=1 in H2 and therefore the interpretation depends mainly on two parameters: He mixing ratio of the lower atmosphere and K_z. The occultations of Koskinen et al (2015) give K_z with an accuracy that has never been possible before and the combination of occultations and airglow therefore provide estimates of the mixing ratio in the lower atmosphere. We make these estimates at several locations that can be reasonably studied with both occultations and airglow and then average the results. Our results lead to a greatly improved estimate of the mixing ratio of He in the upper atmosphere and below. The second objective is to constrain the dynamics in the atmosphere by using the estimate of the He mixing ratio from the main objective. Once we have an estimate of the He mixing ratio in the lower atmosphere that agrees with both occultations and airglow, helium becomes an effective tracer species as any variations in the Cassini UVIS helium data are direct indicator of changes in K_z i.e., dynamics. Our third objective is to connect this work to our Cassini UVIS data He 584 Å airglow analyses as they both cover the time span of the observations and allow us to monitor changes in the airglow observations that may correlate with changes in the state of the atmosphere as revealed by the occultations Saturn's upper thermosphere. This work helps to determine the </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active">4</li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active">5</li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006ihy..workE.135S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006ihy..workE.135S">OI 630.0 nm Night Airglow Observations during the Geomagnetic Storm on November 20, 2003 at Kolhapur (P43)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sharma, A. K.; et al. 2006-11-01 sharma_ashokkumar@yahoo.com The ground based photometric observations of OI 630 nm emission line have been carried out from Kolhapur station (Geog. Lat.16.8˚N, Geo. Long 74.2˚E), India during the period of the largest geomagnetic storm of the solar cycle 23 which occurred on 20 November 2003, with minimum Dst index 472 nT occurring around mid-night hours. We observed that on 19 November 2003 which was geomagnetically quiet day, the airglow activity of OI 630 nm emission was subdued and it was decreasing monotonically. However, on the night of November 20, 2003 the enhancement is observed during geomagnetic storm due to the increased electron density at the altitude of the F region which is related to the downward transport of electron from the plasmasphere to the F-region. Airglow intensity at OI 630.0 nm showed increase around midnight on November 21, 2003 but comparatively on a smaller scale. On this night the DST index was about 100 nT. This implies that the effect of the geomagnetic storm persisted on that night also. These observations have been explained by the penetration magnetospheric electric field to the low latitude region and the subsequent modulation of meridional wind during the magnetic disturbance at night. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.8154K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.8154K">16 years of airglow measurement with astronomical facilities</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kausch, Wolfgang; Noll, Stefan; Kimeswenger, Stefan; Unterguggenberger, Stefanie; Jones, Amy; Proxauf, Bastian 2017-04-01 Observations taken with ground-based astronomical telescopes are affected by various airglow emission processes in the Earth's upper atmosphere. This chemiluminescent emission can be used to investigate the physical state of the meso- and the thermosphere. By applying a modified approach of techniques originally developed to characterise and remove these features from the astronomical spectra, which are not primarily taken for airglow studies, these spectra are suitable for airglow research. For our studies, we currently use data from two observing sites on both hemispheres for our studies: The European Southern Observatory operates four 8m telescopes at the Very Large Telescope (VLT) in the Chilean Atacama desert (24.6°S, 70.4°W). The 2.5m Sloan Digital Sky Survey telescope (SDSS) located in New Mexico/USA (32.8°N, 105.8°W) provides observations from the northern hemisphere. Each of these telescopes is equipped with several astronomical instruments. Among them are several spectrographs operating in the optical and near-IR regime with medium to high spectral resolution. Currently, we work on data from the following three spectrographs (1) UVES@VLT (Ultraviolet and Visual Echelle Spectrograph): This instrument provides spectra in the wavelength regime from 0.3 to 1.1μm in small spectral ranges. Its high resolving power (up to R˜110 000) allows a detailed study of oxygen (OI@557nm, OI@630nm), sodium (NaD@589nm), nitrogen (NI@520nm), and many OH bands. UVES has been in operation since 1999 providing the longest time series. (2) X-Shooter@VLT: This spectrograph is unique as it provides the whole wavelength range from 0.3 to 2.5μm at once with medium resolving power (R˜3 300 to 18 000, depending on the setup). This enables us to study the dependency of optical and near-IR airglow processes simultaneously, e.g. the OH bands. In addition, weak airglow continuum emission, e.g. arising from FeO and NiO can be studied. In operation since 2009, the data cover half a </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSA23B..07F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSA23B..07F">HF-enhanced 4278-Å airglow: evidence of accelerated ionosphere electrons?</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fallen, C. T.; Watkins, B. J. 2013-12-01 We report calculations from a one-dimensional physics-based self-consistent ionosphere model (SCIM) demonstrating that HF-heating of F-region electrons can produce 4278-Å airglow enhancements comparable in magnitude to those reported during ionosphere HF modification experiments at the High-frequency Active Auroral Research Program (HAARP) observatory in Alaska. These artificial 'blue-line' emissions, also observed at the EISCAT ionosphere heating facility in Norway, have been attributed to arise solely from additional production of N2+ ions through impact ionization of N2 molecules by HF-accelerated electrons. Each N2+ ion produced by impact ionization or photoionization has a probability of being created in the N2+(1N) excited state, resulting in a blue-line emission from the allowed transition to its ground state. The ionization potential of N2 exceeds 18 eV, so enhanced impact ionization of N2 implies that significant electron acceleration processes occur in the HF-modified ionosphere. Further, because of the fast N2+ emission time, measurements of 4278-Å intensity during ionosphere HF modification experiments at HAARP have also been used to estimate artificial ionization rates. To the best of our knowledge, all observations of HF-enhanced blue-line emissions have been made during twilight conditions when resonant scattering of sunlight by N2+ ions is a significant source of 4278-Å airglow. Our model calculations show that F-region electron heating by powerful O-mode HF waves transmitted from HAARP is sufficient to increase N2+ ion densities above the shadow height through temperature-enhanced ambipolar diffusion and temperature-suppressed ion recombination. Resonant scattering from the modified sunlit region can cause a 10-20 R increase in 4278-Å airglow intensity, comparable in magnitude to artificial emissions measured during ionosphere HF-modification experiments. This thermally-induced artificial 4278-Å aurora occurs independently of any artificial </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720018659','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720018659">An atlas of low latitude 6300A (01) night airglow from OGO-4 observations</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Reed, E. I.; Fowler, W. B.; Blamont, J. E. 1972-01-01 The atomic oxygen emission line at 6300 A, measured in the nadir direction by a photometer on the polar orbiting satellite OGO-4, was plotted between 40 deg N and 40 deg S latitude on a series of maps for the moon-free periods between 30 August 1967 and 10 January 1968 The longitudinal and local time variations which occur during the northern fall-winter season are indicated. The northern tropical arc is more widespread while the southern arc is not present at all longitudes. The conditions under which the observations were made are described, and four airglow maps were selected to show the local time variations. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSA33A2424C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSA33A2424C">Relationship between Ripples and Gravity Waves Observed in OH Airglow over the Andes Lidar Observatory</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Cao, B.; Gelinas, L. J.; Liu, A. Z.; Hecht, J. H. 2016-12-01 Instabilities generated by large amplitude gravity waves are ubiquitous in the mesopause region, and contribute to the strong forcing on the background atmosphere. Gravity waves and ripples generated by instability are commonly detected by high resolution airglow imagers that measure the hydroxyl emissions near the mesopause ( 87 km). Recently, a method based on 2D wavelet is developed by Gelinas et al. to characterize the statistics of ripple parameters from the Aerospace Infrared Camera at Andes Lidar Observatory located at Cerro Pachón, Chile (70.74°W, 30.25°S). In the meantime, data from a collocated all-sky imager is used to derive gravity wave parameters and their statistics. In this study, the relationship between the ripples and gravity waves that appeared at the same time and location are investigated in terms of their orientations, magnitudes and scales, to examine the statistical properties of the gravity wave induced instabilities and the ripples they generate. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..307..207N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..307..207N">Extreme ultraviolet spectra of Venusian airglow observed by EXCEED</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Nara, Yusuke; Yoshikawa, Ichiro; Yoshioka, Kazuo; Murakami, Go; Kimura, Tomoki; Yamazaki, Atsushi; Tsuchiya, Fuminori; Kuwabara, Masaki; Iwagami, Naomoto 2018-06-01 Extreme ultraviolet (EUV) spectra of Venus in the wavelength range 520 - 1480 Å with 3 - 4 Å resolutions were obtained in March 2014 by an EUV imaging spectrometer EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) on the HISAKI spacecraft. Due to its high sensitivity and long exposure time, many new emission lines and bands were identified. Already known emissions such as the O II 834 Å, O I 989 Å, H ILy - β 1026 Å, and the C I 1277 Å lines (Broadfoot et al., 1974; Bertaux et al., 1980; Feldman et al., 2000) are also detected in the EXCEED spectrum. In addition, N2 band systems such as the Lyman-Birge-Hopfield (a 1Πg - X 1Σg+) (2, 0), (2, 1), (3, 1), (3, 2) and (5, 3) bands, the Birge-Hopfield (b1Πu - X 1 Σg+) (1, 3) band, and the Carroll-Yoshino (c 4‧ 1 Σu+ - X 1Σg+) (0, 0) and (0, 1) bands together are identified for the first time in the Venusian airglow. We also identified the CO Hopfield-Birge (B 1Σ+ - X 1Σ+) (1, 0) band in addition to the already known (0, 0) band, and the CO Hopfield-Birge (C 1Σ+ - X 1Σ+) (0, 1), (0, 2) bands in addition to the already known (0, 0) band (Feldman et al., 2000; Gérard et al., 2011). </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930026421&hterms=bear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dbear','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930026421&hterms=bear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dbear">Berkeley extreme-ultraviolet airglow rocket spectrometer - BEARS</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Cotton, D. M.; Chakrabarti, S. 1992-01-01 The Berkeley EUV airglow rocket spectrometer (BEARS) instrument is described. The instrument was designed in particular to measure the dominant lines of atomic oxygen in the FUV and EUV dayglow at 1356, 1304, 1027, and 989 A, which is the ultimate source of airglow emissions. The optical and mechanical design of the instrument, the detector, electronics, calibration, flight operations, and results are examined. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSA11A..05A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSA11A..05A">Cassini UVIS Observations of Titan Ultraviolet Airglow Spectra with Laboratory Modeling from Electron- and Proton-Excited N2 Emission Studies</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ajello, J. M.; West, R. A.; Malone, C. P.; Gustin, J.; Esposito, L. W.; McClintock, W. E.; Holsclaw, G. M.; Stevens, M. H. 2011-12-01 Joseph M. Ajello, Robert A. West, Rao S. Mangina Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 Charles P. Malone Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 & Department of Physics, California State University, Fullerton, CA 92834 Michael H. Stevens Space Science Division, Naval Research Laboratory, Washington, DC 20375 Jacques Gustin Laboratoire de Physique Atmosphérique et Planétaire, Université de Liège, Liège, Belgium A. Ian F. Stewart, Larry W. Esposito, William E. McClintock, Gregory M. Holsclaw Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 E. Todd Bradley Department of Physics, University of Central Florida, Orlando, FL 32816 The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed photon emissions of Titan's day and night limb-airglow and disk-airglow on multiple occasions, including three eclipse observations from 2009 through 2010. The 77 airglow observations analyzed in this paper show EUV (600-1150 Å) and FUV (1150-1900 Å) atomic multiplet lines and band emissions (lifetimes less than ~100 μs), including the Lyman-Birge-Hopfield (LBH) band system, arising from photoelectron induced fluorescence and solar photo-fragmentation of molecular nitrogen (N2). The altitude of peak UV emission on the limb of Titan during daylight occurred inside the thermosphere/ionosphere (near 1000 km altitude). However, at night on the limb, the same emission features, but much weaker in intensity, arise in the lower atmosphere below 1000 km (lower thermosphere, mesosphere, haze layer) extending downwards to near the surface at ~300 km, possibly resulting from proton- and/or heavier ion-induced emissions as well as secondary-electron-induced emissions. The eclipse observations are unique. UV emissions were observed during only one of the three eclipse events, and no Vegard-Kaplan (VK) or LBH emissions were seen. Through regression analysis using </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA24A..07G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA24A..07G">Statistical comparisons of gravity wave features derived from OH airglow and SABER data</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gelinas, L. J.; Hecht, J. H.; Walterscheid, R. L. 2017-12-01 The Aerospace Corporation's near-IR camera (ANI), deployed at Andes Lidar Observatory (ALO), Cerro Pachon Chile (30S,70W) since 2010, images the bright OH Meinel (4,2) airglow band. The imager provides detailed observations of gravity waves and instability dynamics, as described by Hecht et al. (2014). The camera employs a wide-angle lens that views a 73 by 73 degree region of the sky, approximately 120 km x 120 km at 85 km altitude. Image cadence of 30s allows for detailed spectral analysis of the horizontal components of wave features, including the evolution and decay of instability features. The SABER instrument on NASA's TIMED spacecraft provides remote soundings of kinetic temperature profiles from the lower stratosphere to the lower thermosphere. Horizontal and vertical filtering techniques allow SABER temperatures to be analyzed for gravity wave variances [Walterscheid and Christensen, 2016]. Here we compare the statistical characteristics of horizontal wave spectra, derived from airglow imagery, with vertical wave variances derived from SABER temperature profiles. The analysis is performed for a period of strong mountain wave activity over the Andes spanning the period between June and September 2012. Hecht, J. H., et al. (2014), The life cycle of instability features measured from the Andes Lidar Observatory over Cerro Pachon on March 24, 2012, J. Geophys. Res. Atmos., 119, 8872-8898, doi:10.1002/2014JD021726. Walterscheid, R. L., and A. B. Christensen (2016), Low-latitude gravity wave variances in the mesosphere and lower thermosphere derived from SABER temperature observation and compared with model simulation of waves generated by deep tropical convection, J. Geophys. Res. Atmos., 121, 11,900-11,912, doi:10.1002/2016JD024843. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080013140&hterms=saber&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsaber','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080013140&hterms=saber&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsaber">Equatorial Enhancement of the Nighttime OH Mesospheric Infrared Airglow</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Baker, D. J.; Mlynczak, M. G.; Russell, J. M. 2007-01-01 Global measurements of the hydroxyl mesospheric airglow over an extended period of time have been made possible by the NASA SABER infrared sensor aboard the TIMED satellite which has been functioning since December of 2001. The orbital mission has continued over a significant portion of a solar cycle. Experimental data from SABER for several years have exhibited equatorial enhancements of the nighttime mesospheric OH (delta v = 2) airglow layer consistent with the high average diurnal solar flux. The brightening of the OH airglow typically means more H + O3 is being reacted. At both the spring and autumn seasonal equinoxes when the equatorial solar UV irradiance mean is greatest, the peak volume emission rate (VER) of the nighttime Meinel infrared airglow typically appears to be both significantly brighter plus lower in altitude by several kilometres at low latitudes compared with midlatitude findings. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSA33A2423T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSA33A2423T">Long-term variation of horizontal phase velocity and propagation direction of mesospheric and thermospheric gravity waves by using airglow images obtained at Shigarkai, Japan</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Takeo, D.; Kazuo, S.; Hujinami, H.; Otsuka, Y.; Matsuda, T. S.; Ejiri, M. K.; Yamamoto, M.; Nakamura, T. 2016-12-01 Atmospheric gravity waves generated in the lower atmosphere transport momentum into the upper atmosphere and release it when they break. The released momentum drives the global-scale pole-to-pole circulation and causes global mass transport. Vertical propagation of the gravity waves and transportation of momentum depend on horizontal phase velocity of gravity waves according to equation about dispersion relation of waves. Horizontal structure of gravity waves including horizontal phase velocity can be seen in the airglow images, and there have been many studies about gravity waves by using airglow images. However, long-term variation of horizontal phase velocity spectrum of gravity waves have not been studied yet. In this study, we used 3-D FFT method developed by Matsuda et al., (2014) to analyze the horizontal phase velocity spectrum of gravity waves by using 557.7-nm (altitude of 90-100 km) and 630.0-nm (altitude of 200-300 km) airglow images obtained at Shigaraki MU Observatory (34.8 deg N, 136.1 deg E) over 16 years from October 1, 1998 to July 26, 2015. Results about 557.7-nm shows clear seasonal variation of propagation direction of gravity waves in the mesopause region. Between summer and winter, there are propagation direction anisotropies which probably caused by filtering due to zonal mesospheric jet and by difference of latitudinal location of wave sources relative to Shigaraki. Results about 630.0-nm shows clear negative correlation between the yearly power spectrum density of horizontal phase velocity and sunspot number. This negative correlation with solar activity is consistent with growth rate of the Perkins instability, which may play an important role in generating the nighttime medium-scale traveling ionospheric disturbances at middle latitudes. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.P31B2808B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.P31B2808B">Energy balance in Saturn's upper atmosphere: Joint Lyman-α airglow observations with HST and Cassini</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ben-Jaffel, L.; Baines, K. H.; Ballester, G.; Holberg, H. B.; Koskinen, T.; Moses, J. I.; West, R. A.; Yelle, R. V. 2017-12-01 We are conducting Hubble Space Telescope UV spectroscopy of Saturn's disk-reflected Lyman-α line (Ly-α) at the same time as Cassini airglow measurements. Saturn's Ly-α emission is composed of solar and interplanetary (IPH) Ly-α photons scattered by its upper atmosphere. The H I Ly-a line probes different upper atmospheric layers down to the homopause, providing an independent way to investigate the H I abundance and energy balance. However, this is a degenerate, multi-parameter, radiative-transfer problem that depends on: H I column density, scattering process by thermal and superthermal hydrogen, time-variable solar and IPH sources, and instrument calibration. Our joint HST-Cassini campaign should break the degeneracy in the Saturn airglow problem. First, line integrated fluxes simultaneously measured by HST/STIS (dayside) and Cassini/UVIS (nightside), avoiding solar variability, should resolve the solar and IPH sources. Second, high-resolution spectroscopy with STIS will reveal superthermal line broadening not accessible with a low-resolution spectrometer like UVIS. Third, a second visit observing the same limb of Saturn will cross-calibrate the instruments and, with the STIS linewidth information, will yield the H I abundance, a key photochemical parameter not measured by Cassini. Finally, the STIS latitudinal mapping of the Ly-α linewidth will be correlated with Cassini's latitudinal temperature profile of the thermosphere, to provide an independent constraint on the thermospheric energy budget, a fundamental outstanding problem for giant planets. Here, we report the first results from the HST-Cassini campaign. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980007988','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980007988">Consistency Between SC#21REF Solar XUV Energy Input and the 1973 Pioneer 10 Observations of the Jovian Photoelectron Excited H2 Airglow</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Gangopadhyay, P.; Ogawa, H. S.; Judge, D. L. 1988-01-01 It has been suggested in the literature that the F74113 solar spectrum for the solar minimum condition needs to be modified to explain the production of photoelectrons in the Earth's atmosphere. We have studied here the effect of another solar minimum spectrum, SC#21REF, on the Jovian upper atmosphere emissions and we have compared the predicted photoelectron excited H2 airglow with the 1973 Pioneer 10 observations, analyzed according to the methodology of Shemansky and Judge (1988). In this model calculation we find that in 1973, the Jovian H2 band emissions can be accounted for almost entirely by photoelectron excitation, if the preflight calibration of the Pioneer 10 ultraviolet photometer is adopted. If the SC#21REF flux shortward of 250 A is multiplied by 2 as proposed by Richards and Torr (1988) then the Pioneer 10 calibration and/or the airglow model used must be modified in order to have a self consistent set of observations. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss029e007455.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss029e007455.html">"Aurora Australis, Airglow, Terminator view taken by the Expedition 29 crew"</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-09-18 ISS029-E-007455 (18 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features Aurora Australis, airglow, Earth?s Terminator and the southeastern Indian Ocean. Nadir coordinates are 51.78 degrees south latitude and 124.41 degrees east longitude. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss029e007500.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss029e007500.html">"Aurora Australis, Airglow, Terminator view taken by the Expedition 29 crew"</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-09-18 ISS029-E-007500 (18 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features the Aurora Australis, airglow and parts of the southeastern Indian Ocean. Nadir coordinates are 50.66 degrees south latitude and 137.70 degrees east longitude. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss029e007502.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss029e007502.html">"Aurora Australis, Airglow, Terminator view taken by the Expedition 29 crew"</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-09-18 ISS029-E-007502 (18 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features Aurora Australis, airglow, and parts of the southeast Indian Ocean. Nadir coordinates are 50.58 degrees south latitude and 138.28 degrees east longitude. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss029e007473.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss029e007473.html">"Aurora Australis, Airglow, Terminator view taken by the Expedition 29 crew"</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-09-18 ISS029-E-007473 (18 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features Aurora Australis, airglow, Earth?s Terminator and parts of the southeast Indian Ocean. Nadir coordinates are 51.53 degrees south latitude and 129.80 degrees east longitude. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940010211','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940010211">Vacuum ultraviolet instrumentation for solar irradiance and thermospheric airglow</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Woods, Thomas N.; Rottman, Gary J.; Bailey, Scott M.; Solomon, Stanley C. 1993-01-01 A NASA sounding rocket experiment was developed to study the solar extreme ultraviolet (EUV) spectral irradiance and its effect on the upper atmosphere. Both the solar flux and the terrestrial molecular nitrogen via the Lyman-Birge-Hopfield bands in the far ultraviolet (FUV) were measured remotely from a sounding rocket on October 27, 1992. The rocket experiment also includes EUV instruments from Boston University (Supriya Chakrabarti), but only the National Center for Atmospheric Research (NCAR)/University of Colorado (CU) four solar instruments and one airglow instrument are discussed here. The primary solar EUV instrument is a 1/4 meter Rowland circle EUV spectrograph which has flown on three rockets since 1988 measuring the solar spectral irradiance from 30 to 110 nm with 0.2 nm resolution. Another solar irradiance instrument is an array of six silicon XUV photodiodes, each having different metallic filters coated directly on the photodiodes. This photodiode system provides a spectral coverage from 0.1 to 80 nm with about 15 nm resolution. The other solar irradiance instrument is a silicon avalanche photodiode coupled with pulse height analyzer electronics. This avalanche photodiode package measures the XUV photon energy providing a solar spectrum from 50 to 12,400 eV (25 to 0.1 nm) with an energy resolution of about 50 eV. The fourth solar instrument is an XUV imager that images the sun at 17.5 nm with a spatial resolution of 20 arc-seconds. The airglow spectrograph measures the terrestrial FUV airglow emissions along the horizon from 125 to 160 nm with 0.2 nm spectral resolution. The photon-counting CODACON detectors are used for three of these instruments and consist of coded arrays of anodes behind microchannel plates. The one-dimensional and two-dimensional CODACON detectors were developed at CU by Dr. George Lawrence. The pre-flight and post-flight photometric calibrations were performed at our calibration laboratory and at the Synchrotron Ultraviolet </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740051042&hterms=1079&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2526%25231079','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740051042&hterms=1079&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2526%25231079">Correlation of 1.65 and 2.15 micron airglow emissions</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kieffaber, L. M. 1974-01-01 The intense infrared airglow is due primarily to vibration-rotation bands of the OH molecule. This airglow has been observed with a 24-in. scanning photometer at two wavelengths. Narrow-band interference filters are used to limit observations to the (9,7) band at 2.15 microns and the (4,2) and (5,3) bands at 1.65 microns. If OH emission results from creation of the excited OH molecule in the v = 9 vibrational state and subsequent cascading through lower vibrational levels, the 1.65 and 2.15 micron radiation will be well correlated in space and time. However, if several mechanisms are involved in producing OH in a variety of initial excitation levels, there is no reason to expect good correlation. Sky maps obtained simultaneously at 1.65 and 2.15 microns show strongly correlated intensity fluctuations. Quantitative analysis of these maps and other investigations of smaller areas of the sky yield correlation coefficients typically in excess of 0.8. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts099-356-026.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts099-356-026.html">Earth limb views with greenish bands of airglow during STS-99</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2000-04-06 STS099-356-026 (11-22 February 2000) ---Because of its time exposure, this STS-99 35mm frame provides a view of several stars. The thin greenish band above the horizon is airglow; radiation emitted by the atmosphere from a layer about 30 kilometers thick and about 100 kilometers altitude. The predominant emission in airglow is the green 5577-Angstrom wavelength emission from atomic oxygen atoms. Airglow is always and everywhere present in the atmosphere; it results from the recombination of molecules that have been broken apart by solar radiation during the day. But airglow is so faint that it can only be seen at night by looking "edge on" at the emission layer, such as the view astronauts have in orbit. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active">5</li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active">6</li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSA23A4051F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSA23A4051F">Geomagnetically conjugate observations of ionospheric and thermospheric variations accompanied with a midnight brightness wave at low latitudes</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fukushima, D.; Shiokawa, K.; Otsuka, Y.; Kubota, M.; Yokoyama, T.; Nishioka, M.; Komonjinda, S.; Yatini, C. Y. 2014-12-01 A midnight brightness wave (MBW) is the phenomenon that the OI (630-nm) airglow enhancement propagates poleward once at local midnight. In this study, we first conducted geomagnetically conjugate observations of 630nm airglow for an MBW at conjugate stations. An airglow enhancement which is considered to be an MBW was observed in the 630-nm airglow images at Kototabang, Indonesia (geomagnetic latitude (MLAT): 10.0S) at around local midnight from 1540 to 1730 UT (from 2240 to 2430 LT) on 7 February 2011. This MBW was propagating south-southwestward, which is geomagnetically poleward, with a velocity of 290 m/s. However, similar wave was not observed in the 630-nm airglow images at Chiang Mai, Thailand (MLAT: 8.9N), which is close to being conjugate point of Kototabang. This result indicates that the MBW does not have geomagnetic conjugacy. We simultaneously observed thermospheric neutral winds observed by a co-located Fabry-Perot interferometer at Kototabang. The observed meridional winds turned from northward (geomagnetically equatorward) to southward (geomagnetically poleward) just before the MBW was observed. The bottomside ionospheric heights observed by ionosondes rapidly decreased at Kototabang and slightly increased at Chiang Mai simultaneously with the MBW passage. In the presentation, we discuss the MBW generation by the observed poleward neutral winds at Kototabang, and the cause of the coinciding small height increase at Chiang Mai by the polarization electric field inside the observed MBW at Kototabang. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E.968G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E.968G">Mars dayside temperature from airglow limb profiles : comparison with in situ measurements and models</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gérard, Jean-Claude; Bougher, Stephen; Montmessin, Franck; Bertaux, Jean-Loup; Stiepen, A. The thermal structure of the Mars upper atmosphere is the result of the thermal balance between heating by EUV solar radiation, infrared heating and cooling, conduction and dynamic influences such as gravity waves, planetary waves, and tides. It has been derived from observations performed from different spacecraft. These include in situ measurements of orbital drag whose strength depends on the local gas density. Atmospheric temperatures were determined from the altitude variation of the density measured in situ by the Viking landers and orbital drag measurements. Another method is based on remote sensing measurements of ultraviolet airglow limb profiles obtained over 40 years ago with spectrometers during the Mariner 6 and 7 flybys and from the Mariner 9 orbiter. Comparisons with model calculations indicate that they both reflect the CO_2 scale height from which atmospheric temperatures have been deduced. Upper atmospheric temperatures varying over the wide range 270-445 K, with a mean value of 325 K were deduced from the topside scale height of the airglow vertical profile. We present an analysis of limb profiles of the CO Cameron (a(3) Pi-X(1) Sigma(+) ) and CO_2(+) doublet (B(2) Sigma_u(+) - X(2) PiΠ_g) airglows observed with the SPICAM instrument on board Mars Express. We show that the temperature in the Mars thermosphere is very variable with a mean value of 270 K, but values ranging between 150 and 400 K have been observed. These values are compared to earlier determinations and model predictions. No clear dependence on solar zenith angle, latitude or season is apparent. Similarly, exospheric variations with F10.7 in the SPICAM airglow dataset are small over the solar minimum to moderate conditions sampled by Mars Express since 2005. We conclude that an unidentified process is the cause of the large observed temperature variability, which dominates the other sources of temperature variations. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUSMSA53A..01B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUSMSA53A..01B">Important Considerations When Using Hydroxyl Airglow Measurements to Determine Climate Trends of the Mesopause Region.</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Burns, G.; French, J. 2007-05-01 Spectral calibrations, airglow and possibly auroral contaminations, solar and telluric absorption features and the selection of transition probabilities can all influence rotational temperatures derived from measurements of hydroxyl airglow intensities. Consideration and examples are given of these influences. Measurements and analyses are outlined for data checking that should be undertaken if a hydroxyl airglow data set is to be used to determine climate trends. Multiple spectral calibrations should be conducted throughout the observing period, with regular inter- comparisons to other calibration sources also required. Uncertainties in spectral calibrations should be expressed as a temperature equivalent. Sufficient spectral scans at maximum resolution should be obtained under all extreme observing conditions (at the lowest solar depression angle operated both morning and night, moon and cloud both separately and combined, aurora and under conditions of enhanced atomic oxygen airglow, and under clear sky conditions but with high atmospheric water vapour content) so that an uncertainty for the derived rotational temperatures can be determined for the established data selection criteria. Once the varying emission and absorption features for the hydroxyl region of interest at your site are understood for the observing site, then the spectral resolution of the observing instrument can be reduced to increase temporal resolution with reasonable confidence. This confidence should be tested by investigating the average rotational temperatures derived from all possible line intensity ratios under the extreme observing conditions noted. If a spectral-fitting rotational temperature determination is used, the residuals from the fit should be summed and similarly examined. Hydroxyl measurements provide a cost effective means of monitoring the temperature of the climate-sensitive mesopause region on an almost nightly basis. If care is taken, they provide a valuable data set </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA33A2576A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA33A2576A">Model simulations of line-of-sight effects in airglow imaging of acoustic and fast gravity waves from ground and space</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Aguilar Guerrero, J.; Snively, J. B. 2017-12-01 Acoustic waves (AWs) have been predicted to be detectable by imaging systems for the OH airglow layer [Snively, GRL, 40, 2013], and have been identified in spectrometer data [Pilger et al., JASP, 104, 2013]. AWs are weak in the mesopause region, but can attain large amplitudes in the F region [Garcia et al., GRL, 40, 2013] and have local impacts on the thermosphere and ionosphere. Similarly, fast GWs, with phase speeds over 100 m/s, may propagate to the thermosphere and impart significant local body forcing [Vadas and Fritts, JASTP, 66, 2004]. Both have been clearly identified in ionospheric total electron content (TEC), such as following the 2013 Moore, OK, EF5 tornado [Nishioka et al., GRL, 40, 2013] and following the 2011 Tohoku-Oki tsunami [e.g., Galvan et al., RS, 47, 2012, and references therein], but AWs have yet to be unambiguously imaged in MLT data and fast GWs have low amplitudes near the threshold of detection; nevertheless, recent imaging systems have sufficient spatial and temporal resolution and sensitivity to detect both AWs and fast GWs with short periods [e.g., Pautet et al., AO, 53, 2014]. The associated detectability challenges are related to the transient nature of their signatures and to systematic challenges due to line-of-sight (LOS) effects such as enhancements and cancelations due to integration along aligned or oblique wavefronts and geometric intensity enhancements. We employ a simulated airglow imager framework that incorporates 2D and 3D emission rate data and performs the necessary LOS integrations for synthetic imaging from ground- and space-based platforms to assess relative intensity and temperature perturbations. We simulate acoustic and fast gravity wave perturbations to the hydroxyl layer from a nonlinear, compressible model [e.g., Snively, 2013] for different idealized and realistic test cases. The results show clear signal enhancements when acoustic waves are imaged off-zenith or off-nadir and the temporal evolution of these </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AnGeo..36..473H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AnGeo..36..473H">Simultaneous 6300 Å airglow and radar observations of ionospheric irregularities and dynamics at the geomagnetic equator</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hickey, Dustin A.; Martinis, Carlos R.; Mendillo, Michael; Baumgardner, Jeffrey; Wroten, Joei; Milla, Marco 2018-03-01 In March 2014 an all-sky imager (ASI) was installed at the Jicamarca Radio Observatory (11.95° S, 76.87° W; 0.3° S MLAT). We present results of equatorial spread F (ESF) characteristics observed at Jicamarca and at low latitudes. Optical 6300 and 7774 Å airglow observations from the Jicamarca ASI are compared with other collocated instruments and with ASIs at El Leoncito, Argentina (31.8° S, 69.3° W; 19.8° S MLAT), and Villa de Leyva, Colombia (5.6° N, 73.52° W; 16.4° N MLAT). We use Jicamarca radar data, in incoherent and coherent modes, to obtain plasma parameters and detect echoes from irregularities. We find that ESF depletions tend to appear in groups with a group-to-group separation around 400-500 km and within-group separation around 50-100 km. We combine data from the three ASIs to investigate the conditions at Jicamarca that could lead to the development of high-altitude, or topside, plumes. We compare zonal winds, obtained from a Fabry-Pérot interferometer, with plasma drifts inferred from the zonal motion of plasma depletions. In addition to the ESF studies we also investigate the midnight temperature maximum and its effects at higher latitudes, visible as a brightness wave at El Leoncito. The ASI at Jicamarca along with collocated and low-latitude instruments provide a clear two-dimensional view of spatial and temporal evolution of ionospheric phenomena at equatorial and low latitudes that helps to explain the dynamics and evolution of equatorial ionospheric/thermospheric processes. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P54A..09S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P54A..09S">Pluto's Far Ultraviolet Spectrum and Airglow Emissions</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Steffl, A.; Schindhelm, E.; Kammer, J.; Gladstone, R.; Greathouse, T. K.; Parker, J. W.; Strobel, D. F.; Summers, M. E.; Versteeg, M. H.; Ennico Smith, K.; Hinson, D. P.; Linscott, I.; Olkin, C.; Parker, A. H.; Retherford, K. D.; Singer, K. N.; Tsang, C.; Tyler, G. L.; Weaver, H. A., Jr.; Woods, W. W.; Young, L. A.; Stern, A. 2015-12-01 The Alice far ultraviolet spectrograph on the New Horizons spacecraft is the second in a family of six instruments in flight on, or under development for, NASA and ESA missions. Here, we present initial results from the Alice observations of Pluto during the historic flyby. Pluto's far ultraviolet spectrum is dominated by sunlight reflected from the surface with absorption by atmospehric constituents. We tentatively identify C2H2 and C2H4 in Pluto's atmosphere. We also present evidence for weak airglow emissions. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EP%26S...69..112F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EP%26S...69..112F">Geomagnetically conjugate observations of ionospheric and thermospheric variations accompanied by a midnight brightness wave at low latitudes</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fukushima, D.; Shiokawa, K.; Otsuka, Y.; Kubota, M.; Yokoyama, T.; Nishioka, M.; Komonjinda, S.; Yatini, C. Y. 2017-08-01 We conducted geomagnetically conjugate observations of 630-nm airglow for a midnight brightness wave (MBW) at Kototabang, Indonesia [geomagnetic latitude (MLAT): 10.0°S], and Chiang Mai, Thailand (MLAT: 8.9°N), which are geomagnetically conjugate points at low latitudes. An airglow enhancement that was considered to be an MBW was observed in OI (630-nm) airglow images at Kototabang around local midnight from 2240 to 2430 LT on February 7, 2011. This MBW propagated south-southwestward, which is geomagnetically poleward, at a velocity of 290 m/s. However, a similar wave was not observed in the 630-nm airglow images at Chiang Mai. This is the first evidence of an MBW that does not have geomagnetic conjugacy, which also implies generation of MBW only in one side of the hemisphere from the equator. We simultaneously observed thermospheric neutral winds observed by a co-located Fabry-Perot interferometer at Kototabang. The observed meridional winds turned from northward (geomagnetically equatorward) to southward (geomagnetically poleward) just before the wave was observed. This indicates that the observed MBW was generated by the poleward winds which push ionospheric plasma down along geomagnetic field lines, thereby increasing the 630-nm airglow intensity. The bottomside ionospheric heights observed by ionosondes rapidly decreased at Kototabang and slightly increased at Chiang Mai. We suggest that the polarization electric field inside the observed MBW is projected to the northern hemisphere, causing the small height increase observed at Chiang Mai. This implies that electromagnetic coupling between hemispheres can occur even though the original disturbance is caused purely by the neutral wind.[Figure not available: see fulltext. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-S39-342-026.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-S39-342-026.html">Aurora Australis, Spiked and Sinuous Red and Green Airglow</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 1991-05-06 STS039-342-026 (28 April-6 May 1991) --- This view of the Aurora Australis, or Southern Lights, shows a band of airglow above the limb of Earth. Photo experts at NASA studying the mission photography identify the airglow as being in the 80-120 kilometer altitude region and attribute its existence to atomic oxygen (wavelength of 5,577 Angstroms), although other atoms can also contribute. The atomic oxygen airglow is usually most intense at altitudes around 65 degrees north and south latitude, and is most intense in the spring and fall of the year. The aurora phenomena is due to atmospheric oxygen and nitrogen being excited by the particles from the Van Allen Radiation belts which extend between the two geomagnetic poles. The red and green rays appear to extend upward to 200-300 kilometers, much higher than the usual upper limits of about 110 kilometers. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..300..386M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..300..386M">Temperature estimation from hydroxyl airglow emission in the Venus night side mesosphere</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Migliorini, A.; Snels, M.; Gérard, J.-C.; Soret, L.; Piccioni, G.; Drossart, P. 2018-01-01 The temperature of the night side of Venus at about 95 km has been determined by using spectral features of the hydroxyl airglow emission around 3 μm, recorded from July 2006 to July 2008 by VIRTIS onboard Venus Express. The retrieved temperatures vary from 145.5 to about 198.1 K with an average value of 176.3 ± 14.3 K and are in good agreement with previous ground-based and space observations. The variability with respect to latitude and local time has been studied, showing a minimum of temperature at equatorial latitudes, while temperature values increase toward mid latitudes with a local maximum at about 35°N. The present work provides an independent contribution to the temperature estimation in the transition region between the Venus upper mesosphere and the lower thermosphere, by using the OH emission as a thermometer, following the technique previously applied to the high-resolution O2(a1Δg) airglow emissions observed from ground. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA51B2406K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA51B2406K">Observations of thunderstorm-related 630 nm airglow depletions</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kendall, E. A.; Bhatt, A. 2015-12-01 The Midlatitude All-sky imaging Network for Geophysical Observations (MANGO) is an NSF-funded network of 630 nm all-sky imagers in the continental United States. MANGO will be used to observe the generation, propagation, and dissipation of medium and large-scale wave activity in the subauroral, mid and low-latitude thermosphere. This network is actively being deployed and will ultimately consist of nine all-sky imagers. These imagers form a network providing continuous coverage over the western United States, including California, Oregon, Washington, Utah, Arizona and Texas extending south into Mexico. This network sees high levels of both medium and large scale wave activity. Apart from the widely reported northeast to southwest propagating wave fronts resulting from the so called Perkins mechanism, this network observes wave fronts propagating to the west, north and northeast. At least three of these anomalous events have been associated with thunderstorm activity. Imager data has been correlated with both GPS data and data from the AIRS (Atmospheric Infrared Sounder) instrument on board NASA's Earth Observing System Aqua satellite. We will present a comprehensive analysis of these events and discuss the potential thunderstorm source mechanism. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JASTP.171..164H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JASTP.171..164H">Influences of CO2 increase, solar cycle variation, and geomagnetic activity on airglow from 1960 to 2015</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Huang, Tai-Yin 2018-06-01 Variations of airglow intensity, Volume Emission Rate (VER), and VER peak height induced by the CO2 increase, and by the F10.7 solar cycle variation and geomagnetic activity were investigated to quantitatively assess their influences on airglow. This study is an extension of a previous study by Huang (2016) covering a time period of 55 years from 1960 to 2015 and includes geomagnetic variability. Two airglow models, OHCD-90 and MACD-90, are used to simulate the induced variations of O(1S) greenline, O2(0,1) atmospheric band, and OH(8,3) airglow for this study. Overall, our results demonstrate that airglow intensity and the peak VER variations of the three airglow emissions are strongly correlated, and in phase, with the F10.7 solar cycle variation. In addition, there is a linear trend, be it increasing or decreasing, existing in the airglow intensities and VERs due to the CO2 increase. On other hand, airglow VER peak heights are strongly correlated, and out of phase, with the Ap index variation of geomagnetic activity. The CO2 increase acts to lower the VER peak heights of OH(8,3) airglow and O(1S) greenline by 0.2 km in 55 years and it has no effect on the VER peak height of O2(0,1) atmospheric band. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss029e005853.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss029e005853.html">Airglow on the horizon against the starry sky view taken by the Expedition 29 crew</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-09-17 ISS029-E-005853 (17 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. The image features airglow on the horizon against a starry sky with Russian spacecraft Soyuz and Progress in the foreground. Nadir coordinates are 27.8 degrees south latitude and 137.6 west longitude. The photo was taken at 11:32:37 GMT, Sept. 17, 2011. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.P53B2186H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.P53B2186H">What generates Callisto's atmosphere? - Indications from calculations of ionospheric electron densities and airglow</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hartkorn, O. A.; Saur, J.; Strobel, D. F. 2016-12-01 Callisto's atmosphere has been probed by the Galileo spacecraft and the Hubble Space Telescope (HST) and is expected to be composed of O2 and minor components CO2 and H2O. We use an ionosphere model coupled with a parametrized atmosphere model to calculate ionospheric electron densities and airglow. By varying a prescribed neutral atmosphere and comparing the model results to Galileo radio occultation and HST-Cosmic Origin Spectrograph observations we find that Callisto's atmosphere likely possesses a day/night asymmetry driven by solar illumination. We see two possible explanation for this asymmetry: 1) If sublimation dominates the atmosphere formation, a day/night asymmetry will be generated since the sublimation production rate is naturally much stronger at the day side than at the night side. 2) If surface sputtering dominates the atmosphere formation, a day/night asymmetry is likely generated as well since the sputtering yield increases with increasing surface temperature and, therefore, with decreasing solar zenith angle. The main difference between both processes is given by the fact that surface sputtering, in contrast to sublimation, is also a function of Callisto's orbital position since sputtering projectiles predominately co-rotate with the Jovian magnetosphere. On this basis, we develop a method that can discriminate between both explanations by comparing airglow observations at different orbital positions with airglow predictions. Our predictions are based on our ionosphere model and an orbital position dependent atmosphere model originally developed for the O2 atmosphere of Europa by Plainaki et al. (2013). </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-STS099-355-024.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-STS099-355-024.html">Earth limb views with greenish bands of airglow during STS-99</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2000-04-06 STS099-355-024 (11-22 February 2000) -- Two separate atmospheric optical phenomena appear in this 35mm photograph captured from the Space Shuttle Endeavour. The thin greenish band above the horizon is airglow; radiation emitted by the atmosphere from a layer about 30-kilometers thick and about 100-kilometers' altitude. The predominant emission in airglow is the green 5577-Angstrom wavelength emission from atomic oxygen atoms, which is also the predominant emission from the aurora. A yellow-orange color is also seen in airglow, which is the emission of the 5800-Angstrom wavelength from sodium atoms. Airglow is always present in the atmosphere; it results from the recombination of molecules that have been broken apart by solar radiation during the day. But airglow is so faint that it can only be seen at night by looking "edge on" at the emission layer, such as the view that astronauts have in Earth orbit. The other phenomenon in the photo appears to be a faint, diffuse red aurora. Red aurora occur from about 200 kilometers to as high as 500 kilometers altitude only in the auroral zones at polar latitudes. They are caused by the emission of 6300- Angstrom wavelength light from oxygen atoms that have been raised to a higher energy level (excited) by collisions with energetic electrons pouring down from the Earth's magnetosphere. The light is emitted when the atoms return to their original unexcited state. With the red light so faint in this picture, scientists are led to believe that the flux density of incoming electrons was small. Also, since there is no green aurora below the red, that indicates that the energy of the incoming electrons was low - higher energy electrons would penetrate deeper into the atmosphere where the green aurora is energized. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JASTP.171..260A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JASTP.171..260A">On the importance of an atmospheric reference model: A case study on gravity wave-airglow interactions</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Amaro-Rivera, Yolián; Huang, Tai-Yin; Urbina, Julio 2018-06-01 The atmospheric reference model utilized in an airglow numerical study is important since airglow emissions depend on the number density of the light-emitting species. In this study, we employ 2-dimensional, nonlinear, time-dependent numerical models, Multiple Airglow Chemistry Dynamics (MACD) and OH Chemistry Dynamics (OHCD), that use the MSISE-90, NRLMSISE-00, and Garcia and Solomon (GS) model data as atmospheric reference models, to investigate gravity wave-induced airglow variations for the OH(8,3) airglow, O2(0,1) atmospheric band, and O(1S) greenline emissions in the Mesosphere and Lower Thermosphere (MLT) region. Our results show that the OHCD-00 produces the largest wave-induced OH(8,3) airglow intensity variation (∼34%), followed by the OHCD-90 (∼30%), then by the OHCD (∼22%). For O(1S) greenline, the MACD produces the largest wave-induced variation (∼33%), followed by the MACD-90 (∼28%), then by MACD-00 (∼26%). As for O2(0,1) atmospheric band, the MACD produces the largest wave-induced variation (∼31%), followed by the MACD-90 and MACD-00 (∼29%). Our study illustrates the importance and the need for a good atmospheric reference model that can accurately represent the atmosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.8423K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.8423K">Investigating the Concept of Using Airglow Measurements to Detect Seismicity on Venus</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kenda, Balthasar; Lognonné, Philippe; Komjathy, Attila; Banerdt, Bruce; Cutts, Jim; Soret, Lauriane; Jackson, Jennifer 2017-04-01 The internal structure and dynamics of Venus are poorly constrained by observations. Seismology is among the best candidates for probing the interior of the planet, and it would also provide indispensable information about the present-day tectonic activity of Venus. However, due to the extreme surface temperatures, a long-duration seismic station seems to be beyond the technical capabilities achievable today. Nonetheless, the thick and dense atmosphere, which strongly couples with the ground, gives rise to the attractive option of detecting seismic waves from quakes within the atmosphere itself (Garcia et al., 2005, Lognonné and Johnson, 2007, 2015) using in-situ or remote-sensing measurements (Cutts et al., 2015). Here, we consider the bright airglow emission of O2 at 1.27 μm on the nightside of Venus and we model the intensity fluctuations induced by Venus quakes. Synthetic seismograms in the airglow layer, at 90-120 km altitude, are computed using normal-mode summation for a fully coupled solid planet-atmosphere system, including the effects of molecular relaxation of CO2 and a radiative boundary condition at the top of the atmosphere (Lognonné et al., 2016). The corresponding variations in the volumetric emission rate, calculated for realistic background intensities of the airglow (Soret et al., 2012), are then vertically integrated to reproduce the signals that would be seen from orbit. The noise level of existing airglow cameras suggests that the Rayleigh waves generated by quakes of magnitude 5 and above occurring on the nightside of the planet may be detectable up to about 60° in epicentral distance. A significant advantage of this technique is that a single orbiting camera may be sufficient to serve the role of a seismic network. By identifying and tracking the waves it is indeed possible to locate the source, estimate the magnitude and measure the horizontal surface-wave propagation velocities on Venus. In particular, it is expected that this would </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720029859&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720029859&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtwilight">Vacuum ultraviolet spectra of the late twilight airglow.</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Buckley, J. L.; Moos, H. W. 1971-01-01 Evaluation of sounding rocket spectra of the late twilight (solar-zenith angle of 120 deg) ultraviolet airglow between 1260 and 1900 A. The only observed features are O I 1304 and 1356. When the instrument looked at an elevation of 17 deg above the western horizon, the brightnesses were 70 and 33 rayleighs, respectively. The upper limits on the total intensity of the Lyman-Birge-Hopfield and Vegard-Kaplan systems of N2 were 26 plus or minus 26 and 55 plus or minus 55 rayleighs, respectively. An estimate shows that a large part of the O I emissions may be due to excitation by conjugate-point electrons. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006PhDT.......206C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006PhDT.......206C">Studies of the polar MLT region using SATI airglow measurements</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Cho, Youngmin To investigate atmospheric dynamics of the MLT (Mesosphere and Lower Thermosphere) region, a ground-based instrument called SATI (Spectral Airglow Temperature Imager) was developed at York University. The rotational temperatures and emission rates of the OH (6-2) Meinel band and the O2 (0-1) Atmospheric band have been measured in the MLT region by the SATI instrument at Resolute Bay (74.68°N, 94.90°W) since November, 2001, and at the King Sejong station (62.22°S, 58.75°W) since February, 2002. The MLT measurements are examined for periodic oscillations in the ambient temperature and airglow emission rate. A dominant and coherent 4-hr oscillation is seen in both the OH and O2 temperature and emission rate at Resolute Bay in November, 2001. Tidal variation with a 12 hour period is shown in hourly averaged temperatures of the season 2001--2002 and the season 2003--2004. In addition, planetary waves with periods of 3 and 4.5 days are also seen in a longer interval. The observations at high latitudes have revealed that temperatures and emission rates are higher around the winter solstice. MLT cooling events were found at Resolute Bay in December, 2001 and February, 2002. They are compared with the UKMO (UK Meteorological Office) stratospheric assimilated data, and the MLT coolings coincide in time with the stratospheric warmings. A consistent inverse relationship of the OH temperatures and temperatures at 0.316 hPa is presented in the comparison. In previous studies of wave perturbations, the background (mean) values were normally subtracted from the instantaneous signal, but in the present investigation this was not done, allowing the long-term relationship to be examined. A positive relationship of the temperature and emission rate is seen from the SATI measurements for both short and long-term variations, suggesting that similar dynamical processes are responsible for both. This relationship is supported by satellite data from the SABER (Sounding of the </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10562E..0WL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10562E..0WL">Atise: a miniature Fourier-transform spectro-imaging concept for surveying auroras and airglow monitoring from a 6/12u cubesat</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Le Courer, E.; Barthelemy, M.; Vialatte, A.; Prugniaux, M.; Bourdarot, G.; Sequies, T.; Monsinjon, P.; Puget, R.; Guerineau, N. 2017-09-01 The nanosatellite ATISE is a mission dedicated to the observation of the emission spectra of the upper atmosphere (i.e. Airglow and Auroras) mainly related to both the solar UV flux and the precipitation of suprathermal particles coming from the solar wind through the magnetosphere. ATISE will measure specifically the auroral emissions, and the airglow (day- and night) in the spectral range between 380 and 900 nm at altitudes between 100 and 350 km. The exposure time will be 1 second in auroral region and 20 s at low latitude regions. The 5 year expected lifetime of this mission should cover almost a half of solar cycle (2 years nominal). This instrument concept is based on an innovative miniaturized Fourier-transform spectrometer (FTS) allowing simultaneous 1 Rayleigh sensitivity detection along six 1.5°x1° limb lines of sight. This 1-2kg payload instrument is hosted in a 12U cubeSat where 6U are allocated to the payload and 6U to the plateform subsystems. This represents a miniaturisation by a factor of 500 on weight and volume compared to previous Arizona-GLO instrument for equivalent performances in the visible. The instrument is based on microSPOC concept developed by ONERA and IPAG using one Fizeau interferometer per line of sight directly glued on top of the half of a very sensitive CMOS Pyxalis HDPYX detector. Three detectors are necessary with a total electrical consumption compatible with a 6U nanoSat. Each interferometer occupies a 1.4 M pixel part of detector, each is placed on an image of the entrance pupil corresponding to a unique direction of the six lines of sight, this in order to have a uniform illumination permitting good spectral Fourier reconstruction from fringes created between the Fizeau plate and the detector itself. Despite a limited 8x6 cm telescope, this configuration takes advantage of FTS multiplex effect and permits us to maximize the throughput and to integrate very faint emission lines over a wide field of view even if the 1 </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930009172','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930009172">Visible Airglow Experiment data analysis</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Abreu, Vincent J. 1990-01-01 The Visible Airglow Experiment (VAE) was designed to provide detailed profiles of the distribution of excited states of atoms and molecules in the upper atmosphere. The studies supported during the funding period (1983 - 1989) have made significant contributions in the area of thermospheric aeronomy, and the progress during the first four years of this period has been reviewed by Hays et al. (1988). The investigations carried out have resulted in more than 20 publications, and these are summarized. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active">6</li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active">7</li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.P11C2518S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.P11C2518S">Pluto's Ultraviolet Airglow and Detection of Ions in the Upper Atmosphere</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Steffl, A.; Young, L. A.; Kammer, J.; Gladstone, R.; Hinson, D. P.; Summers, M. E.; Strobel, D. F.; Stern, S. A.; Weaver, H. A., Jr.; Olkin, C.; Ennico Smith, K. 2017-12-01 In July 2015, the Alice ultraviolet spectrograph aboard the New Horizons spacecraft made numerous observations of Pluto and its atmosphere. We present here the far ultraviolet reflectance spectrum of Pluto and airglow emissions from its atmosphere. At wavelengths greater than 1400Å, Pluto's spectrum is dominated by sunlight reflected from the surface of the planet. Various hydrocarbon species such as C2H4 are detected in absorption of the solar continuum. Below 1400Å, Pluto's atmosphere is opaque and the surface cannot be detected. However, after carefully removing various sources of background light, we see extremely faint airglow emissions (<0.05 Rayleighs/Ångstrom) from Pluto's atmosphere. All of the emissions are produced by nitrogen in various forms: molecular, atomic, and singly ionized. The detection of N+ at 1086Å is the first, and thus far only, direct detection of ions in Pluto's atmosphere. This N+ emission line is produced primarily by dissociative photoionization of molecular N2 by solar EUV photons (energy > 34.7 eV; wavelength < 360Å). Notably absent from Pluto's spectrum are emission lines from argon at 1048 and 1067Å. We place upper limits on the amount of argon in Pluto's atmosphere above the tau=1 level (observed to be at 750km tangent altitude) that are significantly lower than pre-encounter atmospheric models. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940022877','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940022877">Solar and airglow measurements aboard the two suborbital flights NASA 36.098 and 36.107</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Woods, Thomas N. 1994-01-01 This suborbital program, involving the University of Colorado (CU), National Center for Atmospheric Research (NCAR), University of California at Berkeley (UCB), and Boston University (BU), has resulted in two rocket flights from the White Sands Missile Range, one in 1992 and one in 1993 as NASA 36.098 and 36.107 respectively. The rocket payload includes five solar instruments and one airglow instrument from CU/NCAR and one solar instrument and two airglow instruments from UCB/BU. This report discusses results on solar radiation measurements and the study of thermospheric airglow, namely the photoelectron excited emissions from N2 and O, for the CU/NCAR program. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUSMSA43A..03W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUSMSA43A..03W">First Light from Triple-Etalon Fabry-Perot Interferometer for Atmospheric OI Airglow (6300 A)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Watchorn, S.; Noto, J.; Pedersen, T.; Betremieux, Y.; Migliozzi, M.; Kerr, R. B. 2006-05-01 Scientific Solutions, Inc. (SSI) has developed a triple-etalon Fabry-Perot interferometer (FPI) to observe neutral winds in the ionosphere by measuring neutral oxygen (O I) emission at 630.0 nm during the day. This instrument is to be deployed in the SSI airglow building at the Cerro Tololo observatory (30.17S 70.81W) in Chile, in support of the Comm/Nav Outage Forecast System (C/NOFS) project. Post-deployment observation will be made in conjunction with two other Clemson University Fabry-Perots in Peru, creating a longitudinal chain of interferometers for thermospheric observations. These instruments will make autonomous day and night observations of thermospheric dynamics. Instruments of this type can be constructed for a global chain of autonomous airglow observatories. The FPI presented in this talk consists of three independently pressure-controlled etalons, fed collimated light by a front optical train headed by an all-sky lens with a 160-degree field of view. It can be controlled remotely via a web-based service which allows any internet-connected computer to mimic the control computer at the instrument site. In fall 2005, the SSI system was first assembled at the Millstone Hill Observatory in Westford, Massachusetts, and made day and evening observations. It was then moved to the High-frequency Active Auroral Research Project (HAARP) site in Gakona, Alaska, to participate in joint optical/ionospheric heating campaigns. Additionally, natural airglow observations were made, both locally and remotely via the internet from Massachusetts. The Millstone and HAARP observations with two etalons yielded strong 630-nm atmospheric Fraunhofer absorption lines, with some suggestion of the Ring effect. By modeling the atmospheric absorption line as the constant times the corresponding solar absorption -- itself modeled as a Gaussian plus a polynomial -- the absorption feature is subtracted, leaving only the emission feature. Software ring-summing tools developed at the </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950029567&hterms=university+college&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Duniversity%2Bcollege','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950029567&hterms=university+college&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Duniversity%2Bcollege">Interpretation of satellite airglow observations during the March 22, 1979, magnetic storm, using the coupled ionosphere-thermosphere model developed at University College, London</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Parish, H. F.; Gladstone, G. R.; Chakrabarti, S. 1994-01-01 The University of California, Berkeley, extreme ultraviolet spectrometer aboard the U.S. Air Force STP 78-1 satellite measured emission features in the Earth's dayglow due to neutral and ionized species in the atmosphere, in the 35 to 140-nm range. The spectrometer was operating between March 1979 and March 1980, including the period of the magnetic storm on March 22, 1979. Some of these measurements are interpreted using the predictions of the three-dimensional time-dependent coupled ionosphere-thermosphere model developed at University College, London. The observations show a reduction in the atomic oxygen 130.4-nm airglow emission at high northern latitudes following the storm. Model simulations show that this reduction in 130.4-nm emission is associated with an increase in the O2/O ratio. Analysis of model results using electron transport and radiative transport codes show that the brightness of 130.4-nm emission at high latitudes due to resonantly scattered sunlight is approximately twice that due to photoelectron impact excitation. However, the observed decrease in the brightness at high northern latitudes is mainly due to a change in the photoelectron impact source, which contributes approximately 75% of the total, as well as its multiple scattering component; for the photoelectron impact source at 70 deg latitude and 200 km altitude, the reduction in multiple scattering is 1.5 times greater than the reduction in the initial excitation. The reduction in the airglow emission is visible only in the norther n hemisphere because the south pole was not sunlit over the storm period. The comparison of model results with observations suggests that 130.4-nm emission may be useful as a tracer for global changes in the concentration of atomic energy. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JASTP..78...62T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JASTP..78...62T">Simultaneous Rayleigh lidar and airglow measurements of middle atmospheric waves over low latitudes in India</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Taori, A.; Kamalakar, V.; Raghunath, K.; Rao, S. V. B.; Russell, J. M. 2012-04-01 We utilize simultaneous Rayleigh lidar and mesospheric OH and O2 airglow measurements to identify the dominant and propagating waves within 40-95 km altitude regions over a low latitude station Gadanki (13.8° N, 79.2 °E). It is found that waves with 0.4-0.6 h periodicity are common throughout the altitude range of 40-95 km with significant amplitudes. The ground based temperature measurements with lidar and airglow monitoring are found to compare well with SABER data. With simultaneous Rayleigh lidar (temperature) and mesospheric airglow (emission intensity and temperature) measurements, we estimate the amplitude growth and Krassovsky parameters to characterize the propagation and dissipation of these upward propagating waves. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA33A2578H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA33A2578H">Space-borne observation of mesospheric bore by Visible and near Infrared Spectral Imager onboard the International Space Station</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hozumi, Y.; Saito, A.; Sakanoi, T.; Yamazaki, A.; Hosokawa, K. 2017-12-01 Mesospheric bores were observed by Visible and near Infrared Spectral Imager (VISI) of the ISS-IMAP mission (Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere mapping mission from the International Space Station) in O2 airglow at 762 nm wavelength. The mesospheric bore is moving front of sharp jump followed by undulations or turbulence in the mesopause region. Since previous studies of mesospheric bore were mainly based on ground-based airglow imaging that is limited in field-of-view and observing site, little is known about its horizontal extent and global behavior. Space-borne imaging by ISS-IMAP/VISI provides an opportunity to study the mesospheric bore with a wide field-of-view and global coverage. A mesospheric bore was captured by VISI in two consecutive paths on 9 July 2015 over the south of African continent (48ºS - 54ºS and 15ºE). The wave front aligned with south-north direction and propagated to west. The phase velocity and wave length of the following undulation were estimated to 100 m/s and 30 km, respectively. Those parameters are similar to those reported by previous studies. 30º anti-clockwise rotation of the wave front was recognized in 100 min. Another mesospheric bore was captured on 9 May 2013 over the south Atlantic ocean (35ºS - 43ºS and 24ºW - 1ºE) with more than 2,200 km horizontal extent of wave front. The wave front aligned with southeast-northwest direction. Because the following undulation is recognized in the southwest side of the wave front, it is estimated to propagate to northeast direction. The wave front was modulated with 1,000 km wave length. This modulation implies inhomogeneity of the phase velocity. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000038366','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000038366">Gravity Wave Energetics Determined From Coincident Space-Based and Ground-Based Observations of Airglow Emissions</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 2000-01-01 Significant progress was made toward the goals of this proposal in a number of areas during the covered period. Section 5.1 contains a copy of the originally proposed schedule. The tasks listed below have been accomplished: (1) Construction of space-based observing geometry gravity wave model. This model has been described in detail in the paper accompanying this report (Section 5.2). It can simulate the observing geometry of both ground-based, and orbital instruments allowing comparisons to be made between them. (2) Comparisons of relative emission intensity, temperatures, and Krassovsky's ratio for space- and ground-based observing geometries. These quantities are used in gravity wave literature to describe the effects of the waves on the airglow. (3) Rejection of Bates [1992], and Copeland [1994] chemistries for gravity wave modeling purposes. Excessive 02(A(sup 13)(Delta)) production led to overproduction of O2(b(sup 1)(Sigma)), the state responsible for the emission of O2. Atmospheric band. Attempts were made to correct for this behavior, but could not adequately compensate for this. (4) Rejection of MSX dataset due to lack of coincident data, and resolution necessary to characterize the waves. A careful search to identify coincident data revealed only four instances, with only one of those providing usable data. Two high latitude overpasses and were contaminated by auroral emissions. Of the remaining two mid-latitude coincidences, one overflight was obscured by cloud, leaving only one ten minute segment of usable data. Aside from the statistical difficulties involved in comparing measurements taken in this short period, the instrument lacks the necessary resolution to determine the vertical wavelength of the gravity wave. This means that the wave cannot be uniquely characterized from space with this dataset. Since no observed wave can be uniquely identified, model comparisons are not possible. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770003789','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770003789">Post sunset behavior of the 6300 A atomic oxygen airglow emission</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Smith, R. E. 1976-01-01 A theoretical model of the 6300 A OI airglow emission was developed based on the assumptions that both the charged and neutral portions of the Earth's upper atmosphere are in steady state conditions of diffusive equilibrium. Intensities of 6300 A OI emission line were calculated using electron density true height profiles from a standard C-4 ionosonde and exospheric temperatures derived from Fabry-Perot interferometer measurements of the Doppler broadened 6300 A emission line shape as inputs to the model. Reaction rate coefficient values, production mechanism efficiencies, solar radiation fluxes, absorption cross sections, and models of the neutral atmosphere were varied parametrically to establish a set of acceptable inputs which will consistently predict 6300 A emission intensities that closely agree with intensities observed during the post-sunset twilight period by an airglow observatory consisting of a Fabry-Perot interferometer and a turret photometer. Emission intensities that can only result from the dissociative recombination of molecular oxygen ions were observed during the latter portion of the observational period. Theoretical calculations indicate that contamination of the 6300 A OI emission should be on the order of or less than 3 percent; however, these results are very sensitive to the wavelengths of the individual lines and their intensities relative to the 6300 A OI intensity. This combination of a model atmosphere, production mechanism efficiencies, and quenching coefficient values was used when the dissociative photoexcitation and direct impact excitation processes were contributing to the intensity to establish best estimates of solar radiation fluxes in the Schumann--Runge continuum and associated absorption cross sections. Results show that the Jacchia 1971 model of the upper atmosphere combined with the Ackerman recommended solar radiation fluxes and associated absorption cross sections produces theoretically calculated intensities that more </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20733778','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20733778">Berkeley extreme-ultraviolet airglow rocket spectrometer: BEARS.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Cotton, D M; Chakrabarti, S 1992-09-20 We describe the Berkeley extreme-UV airglow rocket spectrometer, which is a payload designed to test several thermospheric remote-sensing concepts by measuring the terrestrial O I far-UV and extreme-UV dayglow and the solar extreme-UV spectrum simultaneously. The instrument consisted of two near-normal Rowland mount spectrometers and a Lyman-alpha photometer. The dayglow spectrometer covered two spectral regions from 980 to 1040 A and from 1300 to 1360 A with 1.5-A resolution. The solar spectrometer had a bandpass of 250-1150 A with an ~ 10-A resolution. All three spectra were accumulated by using a icrochannel-plate-intensified, two-dimensional imaging detector with three separate wedge-and strip anode readouts. The hydrogen Lyman-alpha photometer was included to monitor the solar Lyman-alpha irradiance and geocoronal Lyman-alpha emissions. The instrument was designed, fabricated, and calibrated at the University of California, Berkeley and was successfully launched on 30 September 1988 aboard the first test flight of a four-stage sounding rocket, Black Brant XII. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810043952&hterms=Abreu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DAbreu%252C%2Bc.','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810043952&hterms=Abreu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DAbreu%252C%2Bc.">The O II /7320-7330 A/ airglow - A morphological study</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Yee, J. H.; Abreu, V. J.; Hays, P. B. 1981-01-01 A statistical study of the 7320-30 A airglow arising from the metastable transition between aP and aD states of atomic oxygen ions was conducted by analyzing the data taken from the visible airglow experiment on the Atmosphere Explorer satellites C and E during the time periods between 1974 and 1979. Averaged column emission rate profiles as a function of solar zenith angle and solar activity variation are presented. The galactic background has been carefully subtracted. The result shows that the rate of decreasing emission as a function of solar zenith angle agrees with the theoretical calculation based upon a neutral atmosphere model and the solar spectrum as measured by the EUV spectrometer on the Atmosphere Explorer satellite. Furthermore, an expected increase with solar activity also appeared in a plot of emission brightness versus solar 10.7-cm flux. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980236655','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980236655">Continuing Studies in Support of Ultraviolet Observations of Planetary Atmospheres</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Clark, John 1997-01-01 This program was a one-year extension of an earlier Planetary Atmospheres program grant, covering the period 1 August 1996 through 30 September 1997. The grant was for supporting work to complement an active program observing planetary atmospheres with Earth-orbital telescopes, principally the Hubble Space Telescope (HST). The recent concentration of this work has been on HST observations of Jupiter's upper atmosphere and aurora, but it has also included observations of Io, serendipitous observations of asteroids, and observations of the velocity structure in the interplanetary medium. The observations of Jupiter have been at vacuum ultraviolet wavelengths, including imaging and spectroscopy of the auroral and airglow emissions. The most recent HST observations have been at the same time as in situ measurements made by the Galileo orbiter instruments, as reflected in the meeting presentations listed below. Concentrated efforts have been applied in this year to the following projects: The analysis of HST WFPC 2 images of Jupiter's aurora, including the Io footprint emissions. We have performed a comparative analysis of the lo footprint locations with two magnetic field models, studied the statistical properties of the apparent dawn auroral storms on Jupiter, and found various other repeated patterns in Jupiter's aurora. Analysis and modeling of airglow and auroral Ly alpha emission line profiles from Jupiter. This has included modeling the aurora] line profiles, including the energy degradation of precipitating charged particles and radiative transfer of the emerging emissions. Jupiter's auroral emission line profile is self-absorbed, since it is produced by an internal source, and the resulting emission with a deep central absorption from the overlying atmosphere permits modeling of the depth of the emissions, plus the motion of the emitting layer with respect to the overlying atmospheric column from the observed Doppler shift of the central absorption. By contrast </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA51A2384L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA51A2384L">A new method of derived equatorial plasma bubbles motion by tracing OI 630 nm emission all-sky images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Li, M.; Yu, T.; Chunliang, X.; Zuo, X.; Liu, Z. 2017-12-01 A new method for estimating the equatorial plasma bubbles (EPBs) motions from airglow emission all-sky images is presented in this paper. This method, which is called 'cloud-derived wind technology' and widely used in satellite observation of wind, could reasonable derive zonal and meridional velocity vectors of EPBs drifts by tracking a series of successive airglow 630.0 nm emission images. Airglow emission images data are available from an all sky airglow camera in Hainan Fuke (19.5°N, 109.2°E) supported by China Meridional Project, which can receive the 630.0nm emission from the ionosphere F region at low-latitudes to observe plasma bubbles. A series of pretreatment technology, e.g. image enhancement, orientation correction, image projection are utilized to preprocess the raw observation. Then the regions of plasma bubble extracted from the images are divided into several small tracing windows and each tracing window can find a target window in the searching area in following image, which is considered as the position tracing window moved to. According to this, velocities in each window are calculated by using the technology of cloud-derived wind. When applying the cloud-derived wind technology, the maximum correlation coefficient (MCC) and the histogram of gradient (HOG) methods to find the target window, which mean to find the maximum correlation and the minimum euclidean distance between two gradient histograms in respectively, are investigated and compared in detail. The maximum correlation method is fianlly adopted in this study to analyze the velocity of plasma bubbles because of its better performance than HOG. All-sky images from Hainan Fuke, between August 2014 and October 2014, are analyzed to investigate the plasma bubble drift velocities using MCC method. The data at different local time at 9 nights are studied and find that zonal drift velocity in different latitude at different local time ranges from 50 m/s to 180 m/s and there is a peak value at </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.2222F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.2222F">Geomagnetically conjugate observation of plasma bubbles and thermospheric neutral winds at low latitudes</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fukushima, D.; Shiokawa, K.; Otsuka, Y.; Nishioka, M.; Kubota, M.; Tsugawa, T.; Nagatsuma, T.; Komonjinda, S.; Yatini, C. Y. 2015-03-01 This is the first paper that reports simultaneous observations of zonal drift of plasma bubbles and the thermospheric neutral winds at geomagnetically conjugate points in both hemispheres. The plasma bubbles were observed in the 630 nm nighttime airglow images taken by using highly sensitive all-sky airglow imagers at Kototabang, Indonesia (geomagnetic latitude (MLAT): 10.0°S), and Chiang Mai, Thailand (MLAT: 8.9°N), which are nearly geomagnetically conjugate stations, for 7 h from 13 to 20 UT (from 20 to 03 LT) on 5 April 2011. The bubbles continuously propagated eastward with velocities of 100-125 m/s. The 630 nm images at Chiang Mai and those mapped to the conjugate point of Kototabang fit very well, which indicates that the observed plasma bubbles were geomagnetically connected. The eastward thermospheric neutral winds measured by two Fabry-Perot interferometers were 70-130 m/s at Kototabang and 50-90 m/s at Chiang Mai. We compared the observed plasma bubble drift velocity with the velocity calculated from the observed neutral winds and the model conductivity, to investigate the F region dynamo contribution to the bubble drift velocity. The estimated drift velocities were 60-90% of the observed velocities of the plasma bubbles, suggesting that most of the plasma bubble velocity can be explained by the F region dynamo effect. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730021619','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730021619">Measurements of the Michigan Airglow Observatory from 1971 to 1973 at Ester Dome Alaska</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Mcwatters, K. D.; Meriwether, J. W.; Hays, P. B.; Nagy, A. F. 1973-01-01 The Michigan Airglow Observatory (MAO) was located at Ester Dome Observatory, College, Alaska (latitude: 64 deg 53'N, longitude: 148 deg 03'W) since October, 1971. The MAO houses a 6-inch Fabry-Perot interferometer, a 2-channel monitoring photometer and a 4-channel tilting filter photometer. The Fabry-Perot interferometer was used extensively during the winter observing seasons of 1971-72 and 1972-73 to measure temperature and mass motions of the neutral atmosphere above approximately 90 kilometers altitude. Neutral wind data from the 1971-72 observing season as measured by observing the Doppler shift of the gamma 6300 A atomic oxygen emission line are presented. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..122..846H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..122..846H">Numerical modeling of a multiscale gravity wave event and its airglow signatures over Mount Cook, New Zealand, during the DEEPWAVE campaign</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Heale, C. J.; Bossert, K.; Snively, J. B.; Fritts, D. C.; Pautet, P.-D.; Taylor, M. J. 2017-01-01 A 2-D nonlinear compressible model is used to simulate a large-amplitude, multiscale mountain wave event over Mount Cook, NZ, observed as part of the Deep Propagating Gravity Wave Experiment (DEEPWAVE) campaign and to investigate its observable signatures in the hydroxyl (OH) layer. The campaign observed the presence of a λx=200 km mountain wave as part of the 22nd research flight with amplitudes of >20 K in the upper stratosphere that decayed rapidly at airglow heights. Advanced Mesospheric Temperature Mapper (AMTM) showed the presence of small-scale (25-28 km) waves within the warm phase of the large mountain wave. The simulation results show rapid breaking above 70 km altitude, with the preferential formation of almost-stationary vortical instabilities within the warm phase front of the mountain wave. An OH airglow model is used to identify the presence of small-scale wave-like structures generated in situ by the breaking of the mountain wave that are consistent with those seen in the observations. While it is easy to interpret these feature as waves in OH airglow data, a considerable fraction of the features are in fact instabilities and vortex structures. Simulations suggest that a combination of a large westward perturbation velocity and shear, in combination with strong perturbation temperature gradients, causes both dynamic and convective instability conditions to be met particularly where the wave wind is maximized and the temperature gradient is simultaneously minimized. This leads to the inevitable breaking and subsequent generation of smaller-scale waves and instabilities which appear most prominent within the warm phase front of the mountain wave. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA21A2512K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA21A2512K">Statistical study on the variations of OH and O2 rotational temperatures observed by SATI at King Sejong Station (62.22S, 58.78W), Antarctica</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kim, J.; Kim, J. H.; Jee, G.; Lee, C.; Kim, Y. 2017-12-01 Spectral Airglow Temperature Imager (SATI) installed at King Sejong Station (62.22S, 58.78W), Antarctica, has been continuously measured the airglow emissions from OH (6-2) Meinel and O2 (0-1) atmospheric bands since 2002, in order to investigate the dynamics of the polar MLT region. The measurements allow us to derive the rotational temperature at peak emission heights known as about 87 km and 94 km for OH and O2 airglows, respectively. In this study, we briefly introduce improved analysis technique that modified original analysis code. The major change compared to original program is the improvement of the function to find the exact center position in the observed image. In addition to brief introduction of the improved technique, we also present the results statistically investigating the periodic variations on the temperatures of two layers during the period of 2002 through 2011 and compare our results with those from the temperatures measured by satellite. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.8129B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.8129B">Network for the Detection of Mesopause Change (NDMC): What can we learn from airglow measurements in terms of better understanding atmospheric dynamics?</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bittner, Michael 2013-04-01 The international Network for the Detection of Mesopause Change (NDMC, http://wdc.dlr.de/ndmc) is a global program with the mission to promote international cooperation among research groups investigating the mesopause region (80-100 km) with the goal of early identification of changing climate signals. NDMC is contributing to the European Project "Atmospheric dynamics Research Infrastructure in Europe, ARISE". Measurements of the airglow at the mesopause altitude region (80-100km) from most of the European NDMC stations including spectro-photometers and imagers allow monitoring atmospheric variability at time scales comprising long-term trends, annual and seasonal variability, planetary and gravity waves and infrasonic signals. The measurements also allow validating satellite-based measurements such as from the TIMED-SABER instrument. Examples will be presented for airglow measurements and for related atmospheric dynamics analysis on the abovementioned spatio-temporal scales and comparisons with satellite-based instruments as well as with LIDAR soundings in order to demonstrate the contribution of NDMC to the ARISE project. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..12211794C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..12211794C">The First Use of Coordinated Ionospheric Radio and Optical Observations Over Italy: Convergence of High-and Low-Latitude Storm-Induced Effects</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Cesaroni, C.; Alfonsi, L.; Pezzopane, M.; Martinis, C.; Baumgardner, J.; Wroten, J.; Mendillo, M.; Musicò, E.; Lazzarin, M.; Umbriaco, G. 2017-11-01 Ionospheric storm effects at midlatitudes were analyzed using different ground-based instruments distributed in Italy during the 13-15 November 2012 geomagnetic storm. These included an all-sky imager (ASI) in Asiago (45.8°N, 11.5°E), a network of dual-frequeny Global Navigation Satellite Systems receivers (Rete Integrata Nazionale GPS network), and ionosondes in Rome (41.8°N, 12.5°E) and San Vito (40.6°N, 17.8°E). GPS measurements showed an unusual enhancement of total electron content (TEC) in southern Italy, during the nights of 14 and 15 November. The ASI observed colocated enhancements of 630 nm airglow at the same time, as did variations in NmF2 measured by the ionosondes. Moreover, wave-like perturbations were identified propagating from the north. The Ensemble Empirical Mode Decomposition, applied to TEC values revealed the presence of traveling ionospheric disturbances (TIDs) propagating southward between 01:30 UT and 03:00 UT on 15 November. These TIDs were characterized by weak TEC oscillations ( ±0.5 TEC unit), period of 45 min, and velocity of 500 m/s typical of large-scale TIDs. Optical images showed enhanced airglow entering the field of view of the ASI from the N-NE at 02:00 UT and propagating to the S-SW, reaching the region covered by the GPS stations after 03:00 UT, when TEC fluctuations are very small ( ±0.2 TEC unit). The enhancement of TEC and airglow observed in southern Italy could be a consequence of a poleward expansion of the northern crest of the equatorial ionization anomaly. The enhanced airglow propagating from the north and the TEC waves resulted from energy injected at auroral latitudes as confirmed by magnetometer observations in Scandinavia. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850012171','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850012171">Twilight Intensity Variation of the Infrared Hydroxyl Airglow</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Lowe, R. P.; Gilbert, K. L.; Niciejewski, R. J. 1984-01-01 The vibration rotation bands of the hydroxyl radical are the strongest features in the night airglow and are exceeded in intensity in the dayglow only by the infrared atmospheric bands of oxygen. The variation of intensity during evening twilight is discussed. Using a ground-based Fourier Transform Spectrometer (FTS), hydroxyl intensity measurements as early as 3 deg solar depression were made. Models of the twilight behavior show that this should be sufficient to provide measurement of the main portion of the twilight intensity change. The instrument was equipped with a liquid nitrogen-cooled germanium detector whose high sensitivity combined with the efficiency of the FTS technique permits spectra of the region 1.1 to 1.6 microns at high signal-to-noise to be obtained in two minutes. The use of a polarizer at the entrance aperture of the instrument reduces the intensity of scattered sunlight by a factor of at least ten for zenith observations. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20165509','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20165509">Silicon photodiode as a detector in the rocket-borne photometry of the near infrared airglow.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Schaeffer, R C 1976-11-01 The application of a silicon P-I-N photodiode to the dc measurement of low levels of near ir radiation is described. It is shown that the threshold of signal detection is set by the current amplifier voltage noise, the effect of which at the output is determined by the value of source resistance of the photodiode. The photodiode was used as the detector in a compact interference filter photometer designed for rocket-borne studies of the airglow. Flight results have proved the instrument's capability to provide measurements sufficiently precise to yield an accurate height profile of the (0-0) atmospheric band of O(2) night airglow at lambda762 nm. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active">7</li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active">8</li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PASP..128i4504N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PASP..128i4504N">Spatial and Temporal Stability of Airglow Measured in the Meinel Band Window at 1191.3 nm</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Nguyen, Hien T.; Zemcov, Michael; Battle, John; Bock, James J.; Hristov, Viktor; Korngut, Phillip; Meek, Andrew 2016-09-01 We report on the temporal and spatial fluctuations in the atmospheric brightness in the narrow band between Meinel emission lines at 1191.3 nm using a λ/Δλ = 320 near-infrared instrument. We present the instrument design and implementation, followed by a detailed analysis of data taken over the course of a night from Table Mountain Observatory. At low airmasses, the absolute sky brightness at this wavelength is found to be 5330 ± 30 nW m-2 sr-1, consistent with previous measurements of the inter-band airglow at these wavelengths. This amplitude is larger than simple models of the continuum component of the airglow emission at these wavelengths, confirming that an extra emissive or scattering component is required to explain the observations. We perform a detailed investigation of the noise properties of the data and find no evidence for a noise component associated with temporal instability in the inter-line continuum. This result demonstrates that in several hours of ˜100 s integrations the noise performance of the instrument does not appear to significantly degrade from expectations, giving a proof of concept that near-infrared line intensity mapping may be feasible from ground-based sites. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740024671','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740024671">The global characteristics of atmosphere emissions in the lower thermosphere and their aeronomic implications. [OGO-4 airglow photometric observations of oxygen</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Reed, E. I.; Chandra, S. 1974-01-01 The green line of atomic oxygen and the Herzberg bands of molecular oxygen as observed from the OGO-4 airglow photometer are discussed in terms of their spatial and temporal distributions and their relation to the atomic oxygen content in the lower thermosphere. Daily maps of the distribution of emissions show considerable structure (cells, patches, and bands) with appreciable daily changes. When data are averaged over periods of several days in length, the resulting patterns have occasional tendencies to follow geomagnetic parallels. The Seasonal variations are characterized by maxima in both the Northern and Southern Hemispheres in October, with the Northern Hemisphere having substantially higher emission rates. Formulae are derived relating the vertical column emission rates of the green line and the Herzberg bands to the atomic oxygen peak density. Global averages for the time period for these data (August 1967 to January 1968), when converted to maximum atomic oxygen densities near 95 km, have a range of 2.0 x 10 to the 11th power/cu cm 2.7 x 10 to the 11th power/cu cm. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSA12A..07C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSA12A..07C">Simulated GOLD Observations of Atmospheric Waves</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Correira, J.; Evans, J. S.; Lumpe, J. D.; Rusch, D. W.; Chandran, A.; Eastes, R.; Codrescu, M. 2016-12-01 The Global-scale Observations of the Limb and Disk (GOLD) mission will measure structures in the Earth's airglow layer due to dynamical forcing by vertically and horizontally propagating waves. These measurements focus on global-scale structures, including compositional and temperature responses resulting from dynamical forcing. Daytime observations of far-UV emissions by GOLD will be used to generate two-dimensional maps of the ratio of atomic oxygen and molecular nitrogen column densities (ΣO/N2 ) as well as neutral temperature that provide signatures of large-scale spatial structure. In this presentation, we use simulations to demonstrate GOLD's capability to deduce periodicities and spatial dimensions of large-scale waves from the spatial and temporal evolution observed in composition and temperature maps. Our simulations include sophisticated forward modeling of the upper atmospheric airglow that properly accounts for anisotropy in neutral and ion composition, temperature, and solar illumination. Neutral densities and temperatures used in the simulations are obtained from global circulation and climatology models that have been perturbed by propagating waves with a range of amplitudes, periods, and sources of excitation. Modeling of airglow emission and predictions of ΣO/N2 and neutral temperatures are performed with the Atmospheric Ultraviolet Radiance Integrated Code (AURIC) and associated derived product algorithms. Predicted structure in ΣO/N2 and neutral temperature due to dynamical forcing by propagating waves is compared to existing observations. Realistic GOLD Level 2 data products are generated from simulated airglow emission using algorithm code that will be implemented operationally at the GOLD Science Data Center. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740051854&hterms=Dissociative&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DDissociative','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740051854&hterms=Dissociative&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DDissociative">The 6300 A O/1-D/ airglow and dissociative recombination</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Wickwar, V. B.; Cogger, L. L.; Carlson, H. C. 1974-01-01 Measurements of night-time 6300 A airglow intensities at the Arecibo Observatory have been compared with dissociative recombination calculations based on electron densities derived from simultaneous incoherent backscatter measurements. The agreement indicates that the nightglow can be fully accounted for by dissociative recombination. The comparisons are examined to determine the importance of quenching, heavy ions, ionization above the F-layer peak, and the temperature parameter of the model atmosphere. Comparable fits between the observed and calculated intensities are found for several available model atmospheres. The least-squares fitting process, used to make the comparisons, produces comparable fits over a wide range of combinations of neutral densities and of reaction constants. Yet, the fitting places constraints upon the possible combinations; these constraints indicate that the latest laboratory chemical constants and densities extrapolated to a base altitude are mutually consistent. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..12111495S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..12111495S">A statistical analysis of equatorial plasma bubble structures based on an all-sky airglow imager network in China</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sun, Longchang; Xu, Jiyao; Wang, Wenbin; Yuan, Wei; Li, Qinzeng; Jiang, Chaowei 2016-11-01 This paper investigates the statistical features of equatorial plasma bubbles (EPBs) using airglow images from 2012 to 2014 from a ground-based network of four imagers in the equatorial region of China. It is found that (1) EPBs mainly occur during 21:00-00:00 local time (LT) in equinoxes. There is an asymmetry in occurrence rates between March (June) and September equinoxes (December solstices). (2) Most EPBs occur in groups of two to six depletions. The distance between adjacent EPB depletions is 100-700 km, and the average is 200-300 km. The zonal extension of an EPB group is usually less than 1500 km but can reach 3000 km. (3) EPBs usually have a maximum drift velocity near 100 m/s at 21:00-22:00 LT in 9.5° ± 1.5° geomagnetic latitude and then decrease to 50-70 m/s toward sunrise. (4) The averaged westward tilt angle of most EPBs (with respect to the geographic north-south) increased from 5°-10° to 23°-30° with LT between 20:00 and 03:00 LT, then decreasing to 10°-20° toward sunrise. (5) When 90 < F10.7 < 140, the maximum magnetic latitudinal extension (PMLE) is usually lower than 15.0° (apex height 725 km), but it can reach 23.0° (apex height 1330 km) when F10.7 > 140. The maximum PMLE increases by 3.4°-5.5° when F10.7 changes from 90 to 190. (6) The EPB occurrence patterns and zonal drift velocities are significantly different from those at Kolhapur, India, which locates west to our stations by 20.0°-32.0° in longitude. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA31A2570B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA31A2570B">Space Weather Now-Casting for Area-Denied Locations: Testing All-Sky-Imaging Applications at Geomagnetic Conjugate Points.</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Baumgardner, J. L.; Mendillo, M.; Martinis, C. R.; Hickey, D. A.; Wroten, J. 2017-12-01 We explore the concept of using an all-sky-imager (ASI) in one hemisphere to provide now-casting of ionospheric perturbations in the opposite hemisphere. The specific example deals with low-latitude plasma instabilities known as equatorial spread-F (ESF) that depend on geomagnetic field controlled electrodynamics. ASI observations of 630.0 nm airglow from 300 km exhibit regions of low emission ("airglow depletions") that correlate highly with ESF patterns of radiowave disruptions, e.g., from GPS satellites. For both oceanographic and geopolitical reasons, there are vast regions of the globe that cannot be used for ground-based now-casting of local ESF effects. For such area-denied locations, it is possible for observations of airglow depletions from the opposite hemisphere to be used to specify both local and conjugate location environmental impacts. We use fifteen months of ASI observations from the El Leoncito Observatory (Argentina) to predict simultaneous conditions at its trans-equatorial geomagnetic conjugate point in Villa de Leyva (Colombia)—validated by independent ASI observations at that location. We find the success rate of conjugate point now-casting to be greater than 95% for large-scale ESF occurrence patterns. For a different pair of stations at higher magnetic latitudes, three years of observations from the Arecibo Observatory (Puerto Rico) were used to make ESF now-casting at its conjugate point in Mercedes (Argentina) with a 85% success rate. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870038348&hterms=Abreu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAbreu%252C%2Bc.','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870038348&hterms=Abreu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAbreu%252C%2Bc.">The quenching rate of O(1D) by O(3P). [with data from Visible Airglow experiment on AE satellites</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Abreu, V. J.; Yee, J. H.; Solomon, S. C.; Dalgarno, A. 1986-01-01 The rate coefficient for the quenching of O(1D) by O(3P) has recently been calculated by Yee et al. (1985). Their results indicate that quenching by atomic oxygen should not be ignored in the analysis of the 6300 A emission airglow. Data obtained by the Visible Airglow Experiment on board the AE satellites have been reanalyzed to determine the quenching rate of O(1D) by atomic oxygen. The results of this analysis are presented. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRA..117.2317H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRA..117.2317H">Estimating the electron energy distribution during ionospheric modification from spectrographic airglow measurements</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hysell, D. L.; Varney, R. H.; Vlasov, M. N.; Nossa, E.; Watkins, B.; Pedersen, T.; Huba, J. D. 2012-02-01 The electron energy distribution during an F region ionospheric modification experiment at the HAARP facility near Gakona, Alaska, is inferred from spectrographic airglow emission data. Emission lines at 630.0, 557.7, and 844.6 nm are considered along with the absence of detectable emissions at 427.8 nm. Estimating the electron energy distribution function from the airglow data is a problem in classical linear inverse theory. We describe an augmented version of the method of Backus and Gilbert which we use to invert the data. The method optimizes the model resolution, the precision of the mapping between the actual electron energy distribution and its estimate. Here, the method has also been augmented so as to limit the model prediction error. Model estimates of the suprathermal electron energy distribution versus energy and altitude are incorporated in the inverse problem formulation as representer functions. Our methodology indicates a heater-induced electron energy distribution with a broad peak near 5 eV that decreases approximately exponentially by 30 dB between 5-50 eV. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19730052459&hterms=patty&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpatty','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19730052459&hterms=patty&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpatty">Photometer for detection of sodium day airglow.</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Mcmahon, D. J.; Manring, E. R.; Patty, R. R. 1973-01-01 Description of a photometer for daytime ground-based measurements of sodium airglow emission. The photometer described can be characterized by the following principal features: (1) a narrow (4.5-A) interference filter for initial discrimination; (2) cooled photomultiplier detector to reduce noise from dark current fluctuations and chopping to eliminate the average dark current; (3) a sodium vapor resonance cell to provide an effective bandpass comparable to the Doppler line width; (4) separate detection of all light transmitted by the interference filter to evaluate the Rayleigh and Mie components within the Doppler width of the resonance cell; and (5) temperature quenching of the resonance cell to evaluate and account for instrumental imperfections. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss028e017123.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss028e017123.html">Earth Observation</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-07-15 ISS028-E-017123 (16 July 2011) --- Separate atmospheric optical phenomena were captured in this electronic still photograph from the Inernational Space Station. The thin greenish band stretching along the Earth's horizon is airglow; light emitted by the atmosphere from a layer about 30 kilometers thick and about 100 kilometers in altitude. The predominant emission in airglow is the green 5577 Angstrom wavelength light from atomic oxygen atoms. Airglow is always and everywhere present in the atmosphere; it results from the recombination of molecules that have been broken apart by solar radiation during the day. But airglow is so faint that it can only be seen at night by looking "edge on" at the emission layer, such as the view astronauts and cosmonauts have in orbit. The second phenomenon is the appearnce of Aurora Australis. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740044960&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740044960&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtwilight">Twilight airglow. II - N2/+/ emission at 3914 A</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Sharp, W. E. 1974-01-01 One of the experiments aboard a rocket flight carrying instruments to measure the dawn airglow, the ion and electron densities, and the photoelectron spectrum is reported. For a solar zenith angle of 90 deg the emission at 3914 A from N2(+) peaks at about 260 km. The integrated intensity from model calculations suggests that resonance scattering of 3914-A solar photons off N2(+) produces 90% of the emission, whereas simultaneous photoionization excitation of N2(+) produces less than 10% of the emission. Photoelectron impact excitation is found to contribute about 1%. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMAE31B3408W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMAE31B3408W">The D-Region Ledge at Nighttime: Why are Elves Collocated with the OH Meinel Band Airglow Layer?</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Wu, Y. J.; Williams, E. R.; Hsu, R. R. 2014-12-01 The Imager of Sprite and Upper Atmosphere Lightning (ISUAL) onboard the Taiwanese satellite Formosat-2 has continuously observed transient luminous events (TLEs) within the +/-60 degree range of latitude for a decade since May 2004. The lightning electromagnetic pulse is responsible for Elves , the dominate TLE type which accounts for approximately 80% of the total TLE count according to the ISUAL global survey. By analyzing the limb-viewed images with a wavelength filter of 622.8-754nm, 72% of elves are found to be 'glued' to the OH Meinel band (~630nm) nightglow layer within its thickness of 8km, with the OH layer normally at an altitude of 87 km (Huang et al., 2010).This collocation of elves and airglow layer is frequently dismissed as coincidence, since the physical mechanisms for the formation of the two optical phenomena are macroscopically quite different. However, a common ingredient in the atmospheric chemistry is monatomic oxygen. O is needed to make O3 and ultimately hydroxyl OH, the main radiative species of the airglow layer. O is also needed to form nitric oxide NO, the species with the lowest known ionization potential (9.26 eV) in the D-region. Thomas (1990) has documented steep increases in O concentration in the 83-85 km altitude range and Hale (1985) has found steep increases in electrical conductivity in the 84-85 km range, both with rocket measurements. A great simplification of the nighttime ionosphere is the presence of a single photon energy—10.2 eV—Lyman-α, originating in monatomic H in the Earth's geocorona. A simple Chapman layer calculation for the altitude of maximum photo-dissociation of O2, using the measured absorption cross-section of O2 at the Lyman-α energy, shows an altitude of maximum O production at 85 km. Elve emission in the nitrogen first positive band is enhanced by the presence of free electrons from ionized NO, but too large a conductivity will lead to the exclusion of the radiation field from the lightning return </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-s116e06796.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-s116e06796.html">Earth Observations taken by STS-116 Crewmember</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2006-12-18 S116-E-06796 (17 Dec. 2006) --- A blanket of heavy cloud cover, airglow and the blackness of space are featured in this image photographed by a STS-116 crewmember on the International Space Station while Space Shuttle Discovery was docked with the station. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930061209&hterms=atmosphere+wind+profile&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Datmosphere%2Bwind%2Bprofile','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930061209&hterms=atmosphere+wind+profile&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Datmosphere%2Bwind%2Bprofile">WINDII, the wind imaging interferometer on the Upper Atmosphere Research Satellite</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Shepherd, G. G.; Thuillier, G.; Gault, W. A.; Solheim, B. H.; Hersom, C.; Alunni, J. M.; Brun, J.-F.; Brune, S.; Charlot, P.; Cogger, L. L. 1993-01-01 The WIND imaging interferometer (WINDII) was launched on the Upper Atmosphere Research Satellite (UARS) on September 12, 1991. This joint project, sponsored by the Canadian Space Agency and the French Centre National d'Etudes Spatiales, in collaboration with NASA, has the responsibility of measuring the global wind pattern at the top of the altitude range covered by UARS. WINDII measures wind, temperature, and emission rate over the altitude range 80 to 300 km by using the visible region airglow emission from these altitudes as a target and employing optical Doppler interferometry to measure the small wavelength shifts of the narrow atomic and molecular airglow emission lines induced by the bulk velocity of the atmosphere carrying the emitting species. The instrument used is an all-glass field-widened achromatically and thermally compensated phase-stepping Michelson interferometer, along with a bare CCD detector that images the airglow limb through the interferometer. A sequence of phase-stepped images is processed to derive the wind velocity for two orthogonal view directions, yielding the vector horizontal wind. The process of data analysis, including the inversion of apparent quantities to vertical profiles, is described. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA51B2390F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA51B2390F">Ionospheric Observations During a Geomagnetic Storm from LITES on the ISS</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Finn, S. C.; Stephan, A. W.; Cook, T.; Budzien, S. A.; Chakrabarti, S.; Erickson, P. J.; Geddes, G. 2017-12-01 The Limb-Imaging Ionospheric and Thermospheric Extreme-Ultraviolet Spectrograph (LITES) is an extreme-ultraviolet imaging spectrograph that launched in February 2017 and was installed on the International Space Station (ISS). LITES is limb-viewing ( 150 - 350 km tangent altitude) and measures airglow emissions from 60 - 140 nm with 0.2° angular and 1 nm spectral resolutions. We present early LITES results of observations during a G2 geomagnetic storm in April 2017. In addition to LITES data, we will show complementary ground-based incoherent scatter radar (ISR) observations from Millstone Hill during this storm. The combination of LITES EUV space-based observations with the ground-based radio data is an example of the capability of campaign-style measurements of the ionosphere-thermosphere system using multiwavelength ground- and space-based instruments. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA13B..09L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA13B..09L">Comparison of rotational temperature derived from ground-based OH airglow observations with TIMED/SABER to evaluate the Einstein Coefficients</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Liu, W.; Xu, J.; Smith, A. K.; Yuan, W. 2017-12-01 Ground-based observations of the OH(9-4, 8-3, 6-2, 5-1, 3-0) band airglows over Xinglong, China (40°24'N, 117°35'E) from December 2011 to 2014 are used to calculate rotational temperatures. The temperatures are calculated using five commonly used Einstein coefficient datasets. The kinetic temperature from TIMED/SABER is completely independent of the OH rotational temperature. SABER temperatures are weighted vertically by weighting functions calculated for each emitting vibrational state from two SABER OH volume emission rate profiles. By comparing the ground-based OH rotational temperature with SABER's, five Einstein coefficient datasets are evaluated. The results show that temporal variations of the rotational temperatures are well correlated with SABER's; the linear correlation coefficients are higher than 0.72, but the slopes of the fit between the SABER and rotational temperatures are not equal to 1. The rotational temperatures calculated using each set of Einstein coefficients produce a different bias with respect to SABER; these are evaluated over each of vibrational levels to assess the best match. It is concluded that rotational temperatures determined using any of the available Einstein coefficient datasets have systematic errors. However, of the five sets of coefficients, the rotational temperature derived with the Langhoff et al.'s (1986) set is most consistent with SABER. In order to get a set of optimal Einstein coefficients for rotational temperature derivation, we derive the relative values from ground-based OH spectra and SABER temperatures statistically using three year data. The use of a standard set of Einstein coefficients will be beneficial for comparing rotational temperatures observed at different sites. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-S100E5498.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-S100E5498.html">A sunset Earth observation image taken during STS-100</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2001-04-26 S100-E-5498 (26 April 2001) --- Earth's limb--the edge of the planet seen at twilight--was captured with a digital still camera by one of the STS-100 crew members aboard the Space Shuttle Endeavour. Near center frame the silhouette of cloud layers can be seen in the atmosphere, above which lies an airglow layer (left). </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018EP%26S...70...88T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018EP%26S...70...88T">Initiation of a lightning search using the lightning and airglow camera onboard the Venus orbiter Akatsuki</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Takahashi, Yukihiro; Sato, Mitsuteru; Imai, Masataka; Lorenz, Ralph; Yair, Yoav; Aplin, Karen; Fischer, Georg; Nakamura, Masato; Ishii, Nobuaki; Abe, Takumi; Satoh, Takehiko; Imamura, Takeshi; Hirose, Chikako; Suzuki, Makoto; Hashimoto, George L.; Hirata, Naru; Yamazaki, Atsushi; Sato, Takao M.; Yamada, Manabu; Murakami, Shin-ya; Yamamoto, Yukio; Fukuhara, Tetsuya; Ogohara, Kazunori; Ando, Hiroki; Sugiyama, Ko-ichiro; Kashimura, Hiroki; Ohtsuki, Shoko 2018-05-01 The existence of lightning discharges in the Venus atmosphere has been controversial for more than 30 years, with many positive and negative reports published. The lightning and airglow camera (LAC) onboard the Venus orbiter, Akatsuki, was designed to observe the light curve of possible flashes at a sufficiently high sampling rate to discriminate lightning from other sources and can thereby perform a more definitive search for optical emissions. Akatsuki arrived at Venus during December 2016, 5 years following its launch. The initial operations of LAC through November 2016 have included a progressive increase in the high voltage applied to the avalanche photodiode detector. LAC began lightning survey observations in December 2016. It was confirmed that the operational high voltage was achieved and that the triggering system functions correctly. LAC lightning search observations are planned to continue for several years. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSA41B1868R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSA41B1868R">Preliminary Analysis of Images from the Thermospheric Temperature Imager on Fast, Affordable, Science and Technology SATellite (FASTSAT)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Rodriguez, M.; Jones, S.; Mentzell, E.; Gill, N. 2011-12-01 The Thermospheric Temperature Imager (TTI) on Fast, Affordable, Science and Technology SATellite (FASTSAT) measures the upper atmospheric atomic oxygen emission at 135.6 nm and the molecular nitrogen LBH emission at 135.4 nm to determine the atmospheric O/N2 density ratio. Observations of variations in this thermosheric ratio correspond to electron density variations in the ionosphere. The TTI design makes use of a Fabry-Perot interferometer to measure Doppler widened atmospheric emissions to determine neutral atmospheric temperature from low Earth orbit. FASTSAT launched November 10, 2010 and TTI is currently observing geomagnetic signatures in the aurora and airglow. This work is supported by NASA. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023311','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023311">Preliminary Analysis of Images from the Thermospheric Temperature Image on Fast, Affordable, Science and Technology Satellite (FASTSAT)</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Rodriquez, Marcello; Jones, Sarah; Mentzell, Eric; Gill, Nathaniel 2011-01-01 The Thermospheric Temperature Imager (TTI) on Fast, Affordable, Science and Technology SATellite (FASTSAT) measures the upper atmospheric atomic oxygen emission at 135.6 nm and the molecular nitrogen LBH emission at 135.4 nm to determine the atmospheric O/N2 density ratio. Observations of variations in this thermospheric ratio correspond to electron density variations in the ionosphere. The TTI design makes use of a Fabry-Perot interferometer to measure Doppler widened atmospheric emissions to determine neutral atmospheric temperature from low Earth orbit. FASTSAT launched November 10, 2010 and TTI is currently observing geomagnetic signatures in the aurora and airglow. This work is supported by NASA. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active">8</li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active">9</li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993IJRSP..22..197S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993IJRSP..22..197S">All sky imaging Fabry-Perot spectrometer for optical investigation of the upper atmosphere</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sekar, R.; Gurubaran, S.; Sridharan, R. 1993-06-01 A simple optical design, keeping in view of the available components, has been worked out to develop the 'all sky imaging Fabry-Perot spectrometer' to study the spatial structures in thermospheric winds and temperature. This system comprises three subsystems, namely, (1) field widening front-end optics, (2) high resolution Fabry-Perot spectrometer and (3) a two-dimensional detector. The design details of the above imaging spectrometer that has been commissioned for routine observations from Mt. Abu along with the first results on OI 6300 A airglow emission are presented and discussed. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AnGeo..36..311F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AnGeo..36..311F">Case study of mesospheric front dissipation observed over the northeast of Brazil</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fragoso Medeiros, Amauri; Paulino, Igo; Wrasse, Cristiano Max; Fechine, Joaquim; Takahashi, Hisao; Valentin Bageston, José; Paulino, Ana Roberta; Arlen Buriti, Ricardo 2018-03-01 On 3 October 2005 a mesospheric front was observed over São João do Cariri (7.4° S, 36.5° W). This front propagated to the northeast and appeared in the airglow images on the west side of the observatory. By about 1.5 h later, it dissipated completely when the front crossed the local zenith. Ahead of the front, several ripple structures appeared during the dissipative process of the front. Using coincident temperature profile from the TIMED/SABER satellite and wind profiles from a meteor radar at São João do Cariri, the background of the atmosphere was investigated in detail. On the one hand, it was noted that a strong vertical wind shear in the propagation direction of the front produced by a semidiunal thermal tide was mainly responsible for the formation of duct (Doppler duct), in which the front propagated up to the zenith of the images. On the other hand, the evolution of the Richardson number as well as the appearance of ripples ahead of the main front suggested that a presence of instability in the airglow layer that did not allow the propagation of the front to the other side of the local zenith. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JASTP.130..151T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JASTP.130..151T">Plasma bubble monitoring by TEC map and 630 nm airglow image</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Takahashi, H.; Wrasse, C. M.; Otsuka, Y.; Ivo, A.; Gomes, V.; Paulino, I.; Medeiros, A. F.; Denardini, C. M.; Sant'Anna, N.; Shiokawa, K. 2015-08-01 Equatorial ionosphere plasma bubbles over the South American continent were successfully observed by mapping the total electron content (TECMAP) using data provided by ground-based GNSS receiver networks. The TECMAP could cover almost all of the continent within ~4000 km distance in longitude and latitude, monitoring TEC variability continuously with a time resolution of 10 min. Simultaneous observations of OI 630 nm all-sky image at Cachoeira Paulista (22.7°S, 45.0°W) and Cariri (7.4°S, 36.5°W) were used to compare the bubble structures. The spatial resolution of the TECMAP varied from 50 km to 1000 km, depending on the density of the observation sites. On the other hand, optical imaging has a spatial resolution better than 15 km, depicting the fine structure of the bubbles but covering a limited area (~1600 km diameter). TECMAP has an advantage in its spatial coverage and the continuous monitoring (day and night) form. The initial phase of plasma depletion in the post-sunset equatorial ionization anomaly (PS-EIA) trough region, followed by development of plasma bubbles in the crest region, could be monitored in a progressive way over the magnetic equator. In December 2013 to January 2014, periodically spaced bubble structures were frequently observed. The longitudinal spacing between the bubbles was around 600-800 km depending on the day. The periodic form of plasma bubbles may suggest a seeding process related to the solar terminator passage in the ionosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1810082A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1810082A">T he Analysis of the seasonal variations of equatorial plasma bubble, occurrence observed from Oukaimeden Observatory, Morroco</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Amine, Lagheryeb; Zouhair, Benkhaldoun; Jonathan, Makela; Mohamed, Kaab; Aziza, Bounhir; Brian, Hardin; Dan, Fisher; Tmuthy, Duly 2016-04-01 T he Analysis of the seasonal variations of equatorial plasma bubble, occurrence using the 630.0 nm airglow images collected by the PICASSO imager deployed at the Oukkaimden observatory in Morocco. Data have been taken since November 2013 to december 2015. We show the monthly average of appearance of EPBs. A maximum probability for bubble development is seen in the data in January and between late February and early March. We also observe that there are a maximum period of appearance where the plasma is observed (3-5 nights successivies) and we will discuss its connection with the solar activity in storm time. Future analysis will compare the probability of bubble occurrence in our site with the data raised in other observation sites. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018R%26QE..tmp...26S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018R%26QE..tmp...26S">Spatial Characteristics of the 630-nm Artificial Ionospheric Airglow Generation Region During the Sura Facility Pumping</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Shindin, A. V.; Klimenko, V. V.; Kogogin, D. A.; Beletsky, A. B.; Grach, S. M.; Nasyrov, I. A.; Sergeev, E. N. 2018-05-01 We describe the method and the results of modeling and retrieval of the spatial distribution of excited oxygen atoms in the HF-pumped ionospheric region based on two-station records of artificial airglow in the red line (λ = 630 nm). The HF ionospheric pumping was provided by the Sura facility. The red-line records of the night-sky portraits were obtained at two reception points—directly at the heating facility and 170 km east of it. The results were compared with the vertical ionospheric sounding data. It was found that in the course of the experiments the airglow region was about 250 km high and did not depend on the altitude of the pump-wave resonance. The characteristic size of the region was 35 km, and the shape of the distribution isosurfaces was well described by oblique spheroids or a drop-shaped form. The average value of the maximum concentration of excited atoms during the experiment was about 1000 cm-3. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSA51B2170F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSA51B2170F">Geomagnetic conjugate observations of plasma bubbles and thermospheric neutral winds at equatorial latitudes</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fukushima, D.; Shiokawa, K.; Otsuka, Y.; Nishioka, M.; Kubota, M.; Tsugawa, T.; Nagatsuma, T. 2012-12-01 Plasma bubbles are plasma-density depletion which is developed by the Rayleigh-Taylor instability on the sunset terminator at equatorial latitudes. They usually propagate eastward after the sunset. The eastward propagation of the plasma bubbles is considered to be controlled by background eastward neutral winds in the thermosphere through the F-region dynamo effect. However, it is not clear how the F-region dynamo effect contributes to the propagation of the plasma bubbles, because plasma bubbles and background neutral winds have not been simultaneously observed at geomagnetic conjugate points in the northern and southern hemispheres. In this study, geomagnetic conjugate observations of the plasma bubbles at low latitudes with thermospheric neutral winds were reported. The plasma bubbles were observed at Kototabang (0.2S, 100.3E, geomagnetic latitude (MLAT): 10.0S), Indonesia and at Chiang Mai (18.8N, 98.9E, MLAT: 8.9N), Thailand, which are geomagnetic conjugate stations, on 5 April, 2011 from 13 to 22 UT (from 20 to 05 LT). These plasma bubbles were observed in the 630-nm airglow images taken by using highly-sensitive all-sky airglow imagers at both stations. They propagated eastward with horizontal velocities of about 100-125 m/s. Background thermospheric neutral winds were also observed at both stations by using two Fabry-Perot interferometers (FPIs). The eastward wind velocities were about 70-130 m/s at Kototabang, and about 50-90 m/s at Chiang Mai. We estimated ion drift velocities by using these neutral winds observed by FPIs and conductivities calculated from the IRI and MSIS models. The estimated velocities were about 60-90 % of the drift velocities of plasma bubbles. This result shows that most of the plasma bubble drift can be explained by the F-region dynamo effect, and additional electric field effect may come in to play. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMED33C0775B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMED33C0775B">All Sky Imager Network for Science and Education</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bhatt, A.; Kendall, E. A.; Zalles, D. R.; Baumgardner, J. L.; Marshall, R. A.; Kaltenbacher, E. 2012-12-01 A new all sky imager network for space weather monitoring and education outreach has been developed by SRI International. The goal of this program is to install sensitive, low-light all-sky imagers across the continental United States to observe upper atmospheric airglow and aurora in near real time. While aurora borealis is often associated with the high latitudes, during intense geomagnetic storms it can extend well into the continental United States latitudes. Observing auroral processes is instrumental in understanding the space weather, especially in the times of increasing societal dependence on space-based technologies. Under the THEMIS satellite program, Canada has installed a network of all-sky imagers across their country to monitor aurora in real-time. However, no comparable effort exists in the United States. Knowledge of the aurora and airglow across the entire United States in near real time would allow scientists to quickly assess the impact of a geomagnetic storm in concert with data from GPS networks, ionosondes, radars, and magnetometers. What makes this effort unique is that we intend to deploy these imagers at high schools across the country. Selected high-schools will necessarily be in rural areas as the instrument requires dark night skies. At the commencement of the school year, we plan to give an introductory seminar on space weather at each of these schools. Science nuggets developed by SRI International in collaboration with the Center for GeoSpace Studies and the Center for Technology in Learning will be available for high school teachers to use during their science classes. Teachers can use these nuggets as desired within their own curricula. We intend to develop a comprehensive web-based interface that will be available for students and scientific community alike to observe data across the network in near real time and also to guide students towards complementary space weather data sets. This interface will show the real time extent of </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA33B..05G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA33B..05G">Anticipated Observation of Waves and Tides by the GOLD Mission Using a GCM and GLOW model</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Greer, K.; Solomon, S. C.; Rusch, D. W. 2017-12-01 One of the major scientific objectives of the GOLD mission is to address the significance of atmospheric waves and tides propagating from below on the thermospheric temperature structure. Here we examine the modes of tides and spectrum of waves that will be observed by GOLD in geostationary orbit. The GOLD instrument is an imaging spectrograph that will measure the Earth's emissions from 132 to 162 nm. These measurements will be used to image thermospheric temperature and composition near 160 km on the dayside disk at half-hour time scales. TIE-GCM is used to produce a realistic model atmosphere, where different wave and tidal components can be easily extracted, and GLobal AirglOW (GLOW) model produces the emissions in the spectral bands observed by GOLD. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080021265','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080021265">A Multi-Instrument Measurement of a Mesospheric Bore at the Equator</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Shiokawa, K.; Suzuki, S.; Otsuka, Y.; Ogawa, T.; Nakamura, T.; Mlynczak, M. G.; Russell, J. M., III 2005-01-01 We have made a comprehensive measurement of mesospheric bore phenomenon at the equator at Kototabang, Indonesia (0.2 deg S, 100.3 deg E), using an airglow imager, an airglow temperature photometer, a meteor radar, and the SABER instrument on board the TIMED satellite. The bore was detected in airglow images of both OH-band (peak emission altitude: 87 km) and 557.7-nm (96 km) emissions, as east-west front-like structure propagating northward with a velocity of 52-58 m/s. Wave trains with a horizontal wavelength of 30-70 km are observed behind the bore front. The airglow intensity decreases for all the mesospheric emissions of OI (557.7 nm), OH-band, O2-band (altitude: 94 km), and Na (589.3 nm) (90 km) after the bore passage. The rotational temperatures of both OH-band and O2-band also decrease approximately 10 K after the bore passage. An intense shear in northward wind velocity of 80m/s was observed at altitudes of 84-90 km by the meteor radar. Kinetic temperature profile at altitudes of 20-120 km was observed near Kototabang by TIMED/SABER. On the basis of these observations, we discuss generation and ducting of the observed mesospheric bore. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.4243D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.4243D">Observations and Operational Products from the Special Sensor Ultraviolet Limb Imager (SSULI)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Dandenault, Patrick; Nicholas, Andrew C.; Coker, Clayton; Budzien, Scott A.; Chua, Damien H.; Finne, Ted T.; Metzler, Christopher A.; Dymond, Kenneth F. The Naval Research Laboratory (NRL) has developed five ultraviolet remote sensing instru-ments for the Air Force Defense Meteorological Satellite Program (DMSP). These instruments known as SSULI (Special Sensor Ultraviolet Limb Imager) are on the DMSP block of 5D3 satellites, which first launched in 2003. The DMSP satellites are launched in a near-polar, sun-synchronous orbit at an altitude of approximately 830 km. SSULI measures vertical profiles of the natural airglow radiation from atoms, molecules and ions in the upper atmosphere and ionosphere by viewing the earth's limb at a tangent altitude of approximately 50 km to 750 km. Limb observations are made from the extreme ultraviolet (EUV) to the far ultraviolet (FUV) over the wavelength range of 80 nm to 170 nm, with 1.8 nm resolution. An extensive operational data processing system, the SSULI Ground Data Analysis Software (GDAS), has been developed to generate environmental data products from SSULI spectral data in near-real time for use at the Air Force Weather Agency (AFWA). The operational software uses advanced science algorithms developed at NRL and was designed to calibrate data from USAF Raw Sensor Data Records (RSDR) and generate Environmental Data Records (EDRs). Data products from SSULI observations include vertical profiles of electron (Ne) densities, N2, O2, O, O+, Temperature and also vertical Total Electron Content (TEC). On October 18, 2009, the third SSULI sensor launched from Vandenberg Air Force Base, aboard the DMSP F18 spacecraft. An overview of the SSULI operational program and the status of the F18 sensor will be discussed. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000082009&hterms=solar+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolar%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000082009&hterms=solar+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolar%2Benergy">Solar Energy Deposition Rates in the Mesosphere Derived from Airglow Measurements: Implications for the Ozone Model Deficit Problem</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Mlynczak, Martin G.; Garcia, Rolando R.; Roble, Raymond G.; Hagan, Maura 2000-01-01 We derive rates of energy deposition in the mesosphere due to the absorption of solar ultraviolet radiation by ozone. The rates are derived directly from measurements of the 1.27-microns oxygen dayglow emission, independent of knowledge of the ozone abundance, the ozone absorption cross sections, and the ultraviolet solar irradiance in the ozone Hartley band. Fifty-six months of airglow data taken between 1982 and 1986 by the near-infrared spectrometer on the Solar-Mesosphere Explorer satellite are analyzed. The energy deposition rates exhibit altitude-dependent annual and semi-annual variations. We also find a positive correlation between temperatures and energy deposition rates near 90 km at low latitudes. This correlation is largely due to the semiannual oscillation in temperature and ozone and is consistent with model calculations. There is also a suggestion of possible tidal enhancement of this correlation based on recent theoretical and observational analyses. The airglow-derived rates of energy deposition are then compared with those computed by multidimensional numerical models. The observed and modeled deposition rates typically agree to within 20%. This agreement in energy deposition rates implies the same agreement exists between measured and modeled ozone volume mixing ratios in the mesosphere. Only in the upper mesosphere at midlatitudes during winter do we derive energy deposition rates (and hence ozone mixing ratios) consistently and significantly larger than the model calculations. This result is contrary to previous studies that have shown a large model deficit in the ozone abundance throughout the mesosphere. The climatology of solar energy deposition and heating presented in this paper is available to the community at the Middle Atmosphere Energy Budget Project web site at http://heat-budget.gats-inc.com. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910019905','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910019905">Planetary instrument definition and development program: 'Miniature Monochromatic Imager'</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Broadfoot, A. L. 1991-01-01 The miniature monochromatic imager (MMI) development work became the basis for the preparation of several instruments which were built and flown on the shuttle STS-39 as well as being used in ground based experiments. The following subject areas are covered: (1) applications of the ICCD to airglow and auroral measurements and (2) a panchromatic spectrograph with supporting monochromatic imagers. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3297T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3297T">Capability of simultaneous Rayleigh LiDAR and O2 airglow measurements in exploring the short period wave characteristics</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Taori, Alok; Raghunath, Karnam; Jayaraman, Achuthan We use combination of simultaneous measurements made with Rayleigh lidar and O2 airglow monitoring to improve lidar investigation capability to cover a higher altitude range. We feed instantaneous O2 airglow temperatures instead the model values at the top altitude for subsequent integration method of temperature retrieval using Rayleigh lidar back scattered signals. Using this method, errors in the lidar temperature estimates converges at higher altitudes indicating better altitude coverage compared to regular methods where model temperatures are used instead of real-time measurements. This improvement enables the measurements of short period waves at upper mesospheric altitudes (~90 km). With two case studies, we show that above 60 km the few short period wave amplitude drastically increases while, some of the short period wave show either damping or saturation. We claim that by using such combined measurements, a significant and cost effective progress can be made in the understanding of short period wave processes which are important for the coupling across the different atmospheric regions. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012R%26QE...55...33G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012R%26QE...55...33G">Airglow during ionospheric modifications by the sura facility radiation. experimental results obtained in 2010</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Grach, S. M.; Klimenko, V. V.; Shindin, A. V.; Nasyrov, I. A.; Sergeev, E. N.; A. Yashnov, V.; A. Pogorelko, N. 2012-06-01 We present the results of studying the structure and dynamics of the HF-heated volume above the Sura facility obtained in 2010 by measurements of ionospheric airglow in the red (λ = 630 nm) and green (λ = 557.7 nm) lines of atomic oxygen. Vertical sounding of the ionosphere (followed by modeling of the pump-wave propagation) and measurements of stimulated electromagnetic emission were used for additional diagnostics of ionospheric parameters and the processes occurring in the heated volume. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA32A..02S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA32A..02S">Longitudinal Ionospheric Variability Observed by LITES on the ISS</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Stephan, A. W.; Finn, S. C.; Cook, T.; Geddes, G.; Chakrabarti, S.; Budzien, S. A. 2017-12-01 The Limb-Imaging Ionospheric and Thermospheric Extreme-Ultraviolet Spectrograph (LITES) is an imaging spectrograph designed to measure altitude profiles (150-350 km) of extreme- and far-ultraviolet airglow emissions that originate from photochemical processes in the ionosphere and thermosphere. During the daytime, LITES observes the bright O+ 83.4 nm emission from which the ionospheric profile can be inferred. At night, recombination emissions at 91.1 and 135.6 nm provide a direct measure of the electron content along the line of sight. LITES was launched and installed on the International Space Station (ISS) in late February 2017 where it has been operating along with the highly complementary GPS Radio Occultation and Ultraviolet Photometry - Colocated (GROUP-C) experiment. We will present some of the first observations from LITES in April 2017 that show longitudinal patterns in ionospheric density and the daily variability in those patterns. LITES vertical imaging from a vantage point near 410 km enables a particularly unique perspective on the altitude of the ionospheric peak density at night that can complement and inform other ground- and space-based measurements, and track the longitude-altitude variability that is reflective of changes in equatorial electrodynamics. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA31B2344B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA31B2344B">Auroral LSTIDs and SAR Arc Occurrences in Northern California During Geomagnetic Storms</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bhatt, A.; Kendall, E. A. 2015-12-01 A 630nm allsky imager has been operated for two years in northern California at the Hat Creek Radio Observatory. F-region airglow data captured by the imager ranges from approximately L=1.7 -2.7. Since installation of the imager several geomagnetic storms have occurred with varying intensities. Two main manifestations of the geomagnetic storms are observed in the 630 nm airglow data: large-scale traveling ionospheric disturbances that are launched from the auroral zone and Stable Auroral Red (SAR) arcs during more intense geomagnetic storms. We will present a statistical analysis of these storm-time phenomena in northern California for the past eighteen months. This imager is part of a larger all-sky imaging network across the continental United States, termed MANGO (Midlatitude All-sky-imaging Network for Geophysical Observations). Where available, we will add data from networked imagers located at similar L-shell in other states as well. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10256E..4FR','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10256E..4FR">Simulation of the fixed optical path difference of near infrared wind imaging interferometer</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Rong, Piao; Zhang, Chunmin; Yan, Tingyu; Liu, Dongdong; Li, Yanfen 2017-02-01 As an important part of the earth, atmosphere plays a vital role in filtering the solar radiation, adjusting the temperature and organizing the water circulation and keeping human survival. The passive atmospheric wind measurement is based on the imaging interferometer technology and Doppler effect of electromagnetic wave. By using the wind imaging interferometer to get four interferograms of airglow emission lines, the atmospheric wind velocity, temperature, pressure and emission rate can be derived. Exploring the multi-functional and integrated innovation of detecting wind temperature, wind velocity and trace gas has become a research focus in the field. In the present paper, the impact factors of the fixed optical path difference(OPD) of near infrared wind imaging interferometer(NIWII) are analyzed and the optimum value of the fixed optical path difference is simulated, yielding the optimal results of the fixed optical path difference is 20 cm in near infrared wave band (the O2(a1Δg) airglow emission at 1.27 microns). This study aims at providing theoretical basis and technical support for the detection of stratosphere near infrared wind field and giving guidance for the design and development of near infrared wind imaging interferometer. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810054575&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810054575&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight">Observations of neutral iron emission in twilight spectra</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Tepley, C. A.; Meriwether, J. W., Jr.; Walker, J. C. G.; Mathews, J. D. 1981-01-01 A method is presented for the analysis of twilight airglow spectra that may be contaminated by atmospheric continuum emission of unknown brightness. The necessity of correcting for this continuum emission when measuring weak airglow features in twilight is illustrated by application of the method to the neutral iron line at 3860 A. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.P23D2773C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.P23D2773C">Improving MAVEN-IUVS Lyman-Alpha Apoapsis Images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Chaffin, M.; AlMannaei, A. S.; Jain, S.; Chaufray, J. Y.; Deighan, J.; Schneider, N. M.; Thiemann, E.; Mayyasi, M.; Clarke, J. T.; Crismani, M. M. J.; Stiepen, A.; Montmessin, F.; Epavier, F.; McClintock, B.; Stewart, I. F.; Holsclaw, G.; Jakosky, B. M. 2017-12-01 In 2013, the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission was launched to study the Martian upper atmosphere and ionosphere. MAVEN orbits through a very thin cloud of hydrogen gas, known as the hydrogen corona, that has been used to explore the planet's geologic evolution by detecting the loss of hydrogen from the atmosphere. Here we present various methods of extracting properties of the hydrogen corona from observations using MAVEN's Imaging Ultraviolet Spectograph (IUVS) instrument. The analysis presented here uses the IUVS Far Ultraviolet mode apoapase data. From apoapse, IUVS is able to obtain images of the hydrogen corona by detecting the Lyman-alpha airglow using a combination of instrument scan mirror and spacecraft motion. To complete one apoapse observation, eight scan swaths are performed to collect the observations and construct a coronal image. However, these images require further processing to account for the atmospheric MUV background that hinders the quality of the data. Here, we present new techniques for correcting instrument data. For the background subtraction, a multi-linear regression (MLR) routine of the first order MUV radiance was used to improve the images. A flat field correction was also applied by fitting a polynomial to periapse radiance observations. The apoapse data was re-binned using this fit.The results are presented as images to demonstrate the improvements in the data reduction. Implementing these methods for more orbits will improve our understanding of seasonal variability and H loss. Asymmetries in the Martian hydrogen corona can also be assessed to improve current model estimates of coronal H in the Martian atmosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM43A2474Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM43A2474Z">Mesoscale Magnetosphere-Ionosphere Coupling along Open Magnetic Field Lines Associated with Airglow Patches: Field-aligned Currents and Precipitation</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Zou, Y.; Nishimura, Y.; Lyons, L. R.; Shiokawa, K.; Burchill, J. K.; Knudsen, D. J.; Buchert, S. C.; Chen, S.; Nicolls, M. J.; Ruohoniemi, J. M.; McWilliams, K. A.; Nishitani, N. 2016-12-01 Although airglow patches are traditionally regarded as high-density plasma unrelated to local field-aligned currents (FACs) and precipitation, past observations were limited to storm-time conditions. Recent non-storm time observations show patches to be associated with azimuthally narrow ionospheric fast flow channels that substantially contribute to plasma transportation across the polar cap and connect dayside and nightside explosive disturbances. We examine whether non-storm time patches are related also to localized polar cap FACs and precipitation using Swarm- and FAST-imager-radar conjunctions. In Swarm data, we commonly (66%) identify substantial magnetic perturbations indicating FAC enhancements around patches. These FACs have substantial densities (0.1-0.2 μA/m-2) and can be approximated as infinite current sheets (typically 75 km wide) orientated roughly parallel to patches. They usually exhibit a Region-1 sense, i.e. a downward FAC lying eastward of an upward FAC, and can close through Pedersen currents in the ionosphere, implying that the locally enhanced dawn-dusk electric field across the patch is imposed by processes in the magnetosphere. In FAST data, we identify localized precipitation that is enhanced within patches in comparison to weak polar rain outside patches. The precipitation consists of structured or diffuse soft electron fluxes. While the latter resembles polar rain only with higher fluxes, the former consists of discrete fluxes enhanced by 1-2 orders of magnitude from several to several hundred eV. Although the precipitation is not a major contributor to patch ionization, it implies that newly reconnected flux tubes that retain electrons of magnetosheath origin can rapidly traverse the polar cap from the dayside. Therefore non-storm time patches should be regarded as part of a localized magnetosphere-ionosphere coupling system along open magnetic field lines, and their transpolar evolution as a reflection of reconnected flux tubes </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active">9</li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active">10</li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950058911&hterms=twilight&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950058911&hterms=twilight&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dtwilight">Sensitivity of the 6300 A twilight airglow to neutral composition</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Melendez-Alvira, D. J.; Torr, D. G.; Richards, P. G.; Swift, W. R.; Torr, M. R.; Baldridge, T.; Rassoul, H. 1995-01-01 The field line interhemispheric plasma (FLIP) model is used to study the 6300 A line intensity measured during three morning twilights from the McDonald Observatory in Texas. The Imaging Spectrometric Observatory (ISO) measured the 6300 A intensity during the winter of 1987 and the spring and summer of 1988. The FLIP model reproduces the measured intensity and its variation through the twilight well on each day using neutral densities from the MSIS-86 empirical model. This is in spite of the fact that different component sources dominate the integrated volume emission rate on each of the days analyzed. The sensitivity of the intensity to neutral composition is computed by varying the N2, O2, and O densities in the FLIP model and comparing to the intensity computed with the unmodified MSIS-86 densities. The ion densities change self-consistently. Thus the change in neutral composition also changes the electron density. The F2 peak height is unchanged in the model runs for a given day. The intensity changes near 100 deg SZA are comparable to within 10% when either (O2), (N2), or (O) is changed, regardless of which component source is dominant. There is strong sensitivity to changes in (N2) when dissociative recombination is dominant, virtually no change in the nighttime (SZA greater than or equal to 108 deg) intensity with (O2) doubled, and sensitivity of over 50% to doubling or halving (O) at night. When excitation by conjugate photoelectrons is the dominant nighttime component source, the relative intensity change with (O) doubled or halved is very small. This study shows the strong need for simultaneous measurements of electron density and of emissions proportional to photoelectron fluxes if the 6300 A twilight airglow is to be used to retrieve neutral densities. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001EP%26S...53..741K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001EP%26S...53..741K">Characteristics of medium- and large-scale TIDs over Japan derived from OI 630-nm nightglow observation</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kubota, M.; Fukunishi, H.; Okano, S. 2001-07-01 A new optical instrument for studying upper atmospheric dynamics, called the Multicolor All-sky Imaging System (MAIS), has been developed. The MAIS can obtain all-sky images of airglow emission at two different wavelengths simultaneously with a time resolution of several minutes. Since December 1991, imaging observations with the MAIS have been conducted at the Zao observatory (38.09°N, 140.56°E). From these observations, two interesting events with wave structures have been detected in OI 630-nm nightglow images. The first event was observed on the night of June 2/3, 1992 during a geomagnetically quiet period. Simultaneous data of ionospheric parameters showed that they are caused by propagation of the medium-scale traveling ionospheric disturbance (TID). Phase velocity and horizontal wavelength determined from the image data are 45-100 m/s and ~280 km, and the propagation direction is south-westward. The second event was observed on the night of February 27/28, 1992 during a geomagnetic storm. It is found that a large enhancement of OI 630-nm emission is caused by a propagation of the large-scale TID. Meridional components of phase velocities and wavelengths determined from ionospheric data are 305-695 m/s (southward) and 930-5250 km. The source of this large-scale TID appears to be auroral processes at high latitudes. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920014282','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920014282">WAMDII: The Wide Angle Michelson Doppler Imaging Interferometer</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1992-01-01 As part of an effort to learn more about the upper atmosphere and how it is linked to the weather experienced each day, NASA and NRCC are jointly sponsoring the Wide Angle Michelson Doppler Imaging Interferometer (WAMDII) Mission. WAMDII will measure atmospheric temperature and wind speed in the upper atmosphere. In addition to providing data on the upper atmosphere, the wind speed and temperature readings WAMDII takes will also be highly useful in developing and updating computer simulated models of the upper atmosphere. These models are used in the design and testing of equipment and software for Shuttles, satellites, and reentry vehicles. In making its wind speed and temperature measurements, WAMDII examines the Earth's airglow, a faint photochemical luminescence caused by the influx of solar ultraviolet energy into the upper atmosphere. During periods of high solar flare activity, the amount of this UV energy entering the upper atmosphere increases, and this increase may effect airglow emissions. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss030e064161.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss030e064161.html">Earth Observations taken by Expedition 30 crewmember</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2012-02-02 ISS030-E-064161 (2 Feb. 2012) --- Parts of a number of European nations appear in this nighttime image photographed from the International Space Station. The scene, captured by one of the Expedition 30 crew members, shows the British Isles (left, partially obstructed by one of the space station's solar array panels) with London just right of bottom center; the English Channel, which is dark; Paris (lower right corner); and the Netherlands (right side). The greenish airglow is fairly uniform and minor until it transitions to daybreak on the right. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997JGR...10219949Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997JGR...10219949Y">Global simulations and observations of O(1S), O2(1Σ) and OH mesospheric nightglow emissions</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Yee, Jeng-Hwa; Crowley, G.; Roble, R. G.; Skinner, W. R.; Burrage, M. D.; Hays, P. B. 1997-09-01 Despite a large number of observations of mesospheric nightglow emissions in the past, the quantitative comparison between theoretical and experimental brightnesses is rather poor, owing primarily to the short duration of the observations, the strong variability of the tides, and the influence of short-timescale gravity waves. The high-resolution Doppler imager (HRDI) instrument onboard the upper atmosphere research satellite (UARS) provides nearly simultaneous, near-global observations of O(1S) green line, O2(0-1) atmospheric band, and OH Meinel band nightglow emissions. Three days of these observations near the September equinox of 1993 are presented to show the general characteristics of the three emissions, including the emission brightness, peak emission altitude, and their temporal and spatial variabilities. The global distribution of these emissions is simulated on the basis of atmospheric parameters from the recently developed National Center for Atmospheric Research (NCAR) thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM). The most striking features revealed by the global simulation are the structuring of the mesospheric nightglow by the diurnal tides and enhancements of the airglow at high latitudes. The model reproduces the inverse relationship observed by HRDI between the nightglow brightness and peak emission altitude. Analysis of our model results shows that the large-scale latitudinal/tidal nightglow brightness variations are a direct result of a complex interplay between mesospheric and lower thermospheric diffusive and advective processes, acting mainly on the atomic oxygen concentrations. The inclination of the UARS spacecraft precluded observations of high latitude nightglow emissions by HRDI. However, our predicted high-latitude brightness enhancements confirm previous limited groundbased observations in the polar region. This work provides an initial validation of the NCAR-TIMEGCM using airglow data. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740018790','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740018790">Laboratory studies on the excitation and collisional deactivation of metastable atoms and molecules in the aurora and airglow</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Zipf, E. C. 1974-01-01 The aeronomy group at the University of Pittsburgh is actively engaged in a series of coordinated satellite, sounding rocket, and laboratory studies designed to expand and clarify knowledge of the physics and chemistry of planetary atmospheres. Three major discoveries have been made that will lead ultimately to a complete and dramatic revision of our ideas on the ionospheres of Mars, Venus, and the Earth and on the origin of their vacuum ultraviolet airglows. The results have already suggested a new generation of ionosphere studies which probably can be carried out best by laser heterodyning techniques. Laboratory studies have also identified, for the first time, the physical mechanism responsible for the remarkable nitric oxide buildup observed in some auroral arcs. This development is an important break-through in auroral physics, and has military ramifications of considerable interest to the Department of Defense. This work may also shed some light on related NO and atomic nitrogen problems in the mesosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ACP....18.6691D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ACP....18.6691D">The airglow layer emission altitude cannot be determined unambiguously from temperature comparison with lidars</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Dunker, Tim 2018-05-01 I investigate the nightly mean emission height and width of the OH* (3-1) layer by comparing nightly mean temperatures measured by the ground-based spectrometer GRIPS 9 and the Na lidar at ALOMAR. The data set contains 42 coincident measurements taken between November 2010 and February 2014, when GRIPS 9 was in operation at the ALOMAR observatory (69.3° N, 16.0° E) in northern Norway. To closely resemble the mean temperature measured by GRIPS 9, I weight each nightly mean temperature profile measured by the lidar using Gaussian distributions with 40 different centre altitudes and 40 different full widths at half maximum. In principle, one can thus determine the altitude and width of an airglow layer by finding the minimum temperature difference between the two instruments. On most nights, several combinations of centre altitude and width yield a temperature difference of ±2 K. The generally assumed altitude of 87 km and width of 8 km is never an unambiguous, good solution for any of the measurements. Even for a fixed width of ˜ 8.4 km, one can sometimes find several centre altitudes that yield equally good temperature agreement. Weighted temperatures measured by lidar are not suitable to unambiguously determine the emission height and width of an airglow layer. However, when actual altitude and width data are lacking, a comparison with lidars can provide an estimate of how representative a measured rotational temperature is of an assumed altitude and width. I found the rotational temperature to represent the temperature at the commonly assumed altitude of 87.4 km and width of 8.4 km to within ±16 K, on average. This is not a measurement uncertainty. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AdSpR..38.2374C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AdSpR..38.2374C">Observation of temperatures and emission rates from the OH and O 2 nightglow over a southern high latitude station</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Chung, J.-K.; Kim, Y. H.; Won, Y.-I.; Moon, B. K.; Oh, T. H. 2006-01-01 A Spectral Airglow Temperature Imager (SATI) was operated at King Sejong Station (62°13'S, 58°47'W), Korea Antarctic Research Station during the period of March, 2002-September, 2003. We analyze rotational temperatures and emission rates of the O 2 (0-1) and OH (6-2) nightglows obtained at 67 nights with clear sky lasting more than 4 h. A spectral analysis of the dataset shows two dominant oscillations with periods of 4 and 6 h. The 6-h oscillations have a nearly constant phase, whereas the 4-h oscillations have nearly random phases. Although the harmonic periods of both oscillations are suggestive of tidal origin, the 4-h oscillation may have interference by other sources such as gravity waves. The 6-h oscillations could be interpreted as zonally symmetric non-migrating tides because migrating tides except high order modes have very weak amplitudes at high latitudes according to the classical tidal theory. For most cases of the observed oscillations the temperature peak leads the intensity peak, which is consistent with theoretical models for zonally symmetric tides, but contrary to other theoretical models for waves. It is needed to resolve among theoretical models whether or not zonally symmetric tide cause temperature variation prior to intensity variation in mesospheric airglows. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA31A2561S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA31A2561S">Global-scale Observations of the Limb and Disk (GOLD): Science Implementation</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Solomon, S. C.; McClintock, W. E.; Eastes, R.; Anderson, D. N.; Andersson, L.; Burns, A. G.; Codrescu, M.; Daniell, R. E.; England, S.; Eparvier, F. G.; Evans, J. S.; Krywonos, A.; Lumpe, J. D.; Richmond, A. D.; Rusch, D. W.; Siegmund, O.; Woods, T. N. 2017-12-01 The Global-scale Observations of the Limb and Disk (GOLD) is a NASA mission of opportunity that will image the Earth's thermosphere and ionosphere from geostationary orbit. GOLD will investigate how the thermosphere-ionosphere (T-I) system responds to geomagnetic storms, solar radiation, and upward propagating tides and how the structure of the equatorial ionosphere influences the formation and evolution of equatorial plasma density irregularities. GOLD consists of a pair of identical imaging spectrographs that will measure airglow emissions at far-ultraviolet wavelengths from 132 to 162 nm. On the disk, temperature and composition will be determined during the day using emissions from molecular nitrogen Lyman-Birge-Hopfield (LBH) band and atomic oxygen 135.6 nm, and electron density will be derived at night from 135.6 nm emission. On the limb, exospheric temperature will be derived from LBH emission profiles, and molecular oxygen density will be measured using stellar occultations. This presentation describes the GOLD mission science implementation including the as-built instrument performance and the planned observing scenario. It also describes the results of simulations performed by the GOLD team to validate that the measured instrument performance and observing plan will return adequate data to address the science objectives of the mission. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AMT....10.4601S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AMT....10.4601S">Tomographic reconstruction of atmospheric gravity wave parameters from airglow observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Song, Rui; Kaufmann, Martin; Ungermann, Jörn; Ern, Manfred; Liu, Guang; Riese, Martin 2017-11-01 Gravity waves (GWs) play an important role in the dynamics of the mesosphere and lower thermosphere (MLT). Therefore, global observations of GWs in the MLT region are of particular interest. The small scales of GWs, however, pose a major problem for the observation of GWs from space. We propose a new observation strategy for GWs in the mesopause region by combining limb and sub-limb satellite-borne remote sensing measurements for improving the spatial resolution of temperatures that are retrieved from atmospheric soundings. In our study, we simulate satellite observations of the rotational structure of the O2 A-band nightglow. A key element of the new method is the ability of the instrument or the satellite to operate in so-called <q>target mode</q>, i.e. to point at a particular point in the atmosphere and collect radiances at different viewing angles. These multi-angle measurements of a selected region allow for tomographic 2-D reconstruction of the atmospheric state, in particular of GW structures. The feasibility of this tomographic retrieval approach is assessed using simulated measurements. It shows that one major advantage of this observation strategy is that GWs can be observed on a much smaller scale than conventional observations. We derive a GW sensitivity function, and it is shown that <q>target mode</q> observations are able to capture GWs with horizontal wavelengths as short as ˜ 50 km for a large range of vertical wavelengths. This is far better than the horizontal wavelength limit of 100-200 km obtained from conventional limb sounding. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT........63V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT........63V">A study of the feasibility and performance of an active/passive imager using silicon focal plane arrays and incoherent continuous wave laser diodes</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Vollmerhausen, Richard H. This dissertation describes an active/passive imager (API) that provides reliable, nighttime, target acquisition in a man-portable package with effective visual range of about 4 kilometers. The reflective imagery is easier to interpret than currently used thermal imagery. Also, in the active mode, the API provides performance equivalent to the big-aperture, thermal systems used on weapons platforms like tanks and attack helicopters. This dissertation describes the research needed to demonstrate both the feasibility and utility of the API. Part of the research describes implementation of a silicon focal plane array (SFPA) capable of both active and passive imaging. The passive imaging mode exceeds the nighttime performance of currently fielded, man-portable sensors. Further, when scene illumination is insufficient for passive imaging, the low dark current of SFPA makes it possible to use continuous wave laser diodes (CWLD) to add an active imaging mode. CWLD have advantages of size, efficiency, and improved eye safety when compared to high peak-power diodes. Because of the improved eye safety, the API provides user-demanded features like video output and extended range gates in the active as well as passive imaging modes. Like any other night vision device, the API depends on natural illumination of the scene for passive operation. Although it has been known for decades that "starlight" illumination is actually from diffuse airglow emissions, the research described in this dissertation provides the first estimates of the global and temporal variation of ground illumination due to airglow. A third related element of the current research establishes the impact of atmospheric aerosols on API performance. We know from day experience that atmospheric scattering of sunlight into the imager line-of-sight can blind the imager and drastically degrade performance. Atmospheric scattering of sunlight is extensively covered in the literature. However, previous literature did not </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.3258C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.3258C">Observation of upper mesospheric temperatures and emission rates from the OH and O2 nightglow over King Sejong Station, Antartica</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Chung, J.-K.; Kim, Y. H.; Moon, B.-G.; Oh, T.-H.; Won, Y.-I. A spectral airglow temperature imager (SATI) was operated at King Sejong Station (62.22^oS, 301.2^oE), Korea Antarctic Research Station during the period March, 2002 through October, 2003. We analyze data obtained at 24 and 22 nights with clear sky condition lasting more than 6 hours in 2002 and 2003, respectively. A dominant and coherent 4-hr oscillation was seen in both the OH(6-2) and O_2(0-1) band airglow rotational temperatures at two nights, and similar weak features appeared at several nights . The data also show fluctuations of long period that seem to relate to tides, and short period oscillations that could be due to propagating gravity waves. Detailed harmonic analysis will be performed to seasonal data sets to identify any variation in the major atmospheric oscillations over season. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800026554&hterms=day+night&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dday%2Bnight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800026554&hterms=day+night&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dday%2Bnight">O2/1 Delta/ emission in the day and night airglow of Venus</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Connes, P.; Noxon, J. F.; Traub, W. A.; Carleton, N. P. 1979-01-01 An intense airglow from O2(1 Delta) at 1.27 microns on both the light and the dark sides of Venus has been detected by using a ground-based high-resolution Fourier-transform spectrometer. Both dayglow and nightglow are roughly 1,000 times brighter than the visible O2 nightglow found by Veneras 9 and 10 in 1975. The column emission rate of O2(1 Delta) from Venus is close to the rate at which fresh O atoms are produced from photolysis of CO2 on the day side. Formation of O2(1 Delta) is thus a major step in the removal of O atoms from the atmosphere, and dynamical processes must carry these atoms to the night side fast enough to yield a maximum density near 90 km, which is almost constant over the planet. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870007337','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870007337">In search of stratospheric bromine oxide</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Lestrade, John Patrick 1986-01-01 The Imaging Spectrometric Observatory (ISO) is capable of recording spectra in the wavelength range of 200 to 12000 Angstroms. Data from a recent Spacelab 1 ATLAS mission has imaged the terrestrial airglow at tangent ray heights of 90 and 150 km. These data contain information about trace atmospheric constituents such as bromine oxide (BrO), hydroxyl (OH), and chlorine dioxide (OClO). The abundances of these species are critical to stratospheric models of catalytic ozone destruction. Heretofore, very few observations were made especially for BrO. Software was developed to purge unwanted solar features from the airglow spectra. The next step is a measure of the strength of the emission features for BrO. The final analysis will yield the scale height of this important compound. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JASTP.155...86K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JASTP.155...86K">Statistical analysis of mesospheric gravity waves over King Sejong Station, Antarctica (62.2°S, 58.8°W)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kam, Hosik; Jee, Geonhwa; Kim, Yong; Ham, Young-bae; Song, In-Sun 2017-03-01 We have investigated the characteristics of mesospheric short period (<1 h) gravity waves which were observed with all-sky images of OH Meinel band and OI 557 nm airglows over King Sejong Station (KSS) (62.22°S, 58.78°W) during a period of 2008-2015. By applying 2-dimensional FFT to time differenced images, we derived horizontal wavelengths, phase speeds, and propagating directions (188 and 173 quasi-monochromatic waves from OH and OI airglow images, respectively). The majority of the observed waves propagated predominantly westward, implying that eastward waves were filtered out by strong eastward stratospheric winds. In order to obtain the intrinsic properties of the observed waves, we utilized winds simultaneously measured by KSS Meteor Radar and temperatures from Aura Microwave Limb Sounder (MLS). More than half the waves propagated horizontally, as waves were in Doppler duct or evanescent in the vertical direction. This might be due to strong eastward background wind field in the mesosphere over KSS. For freely propagating waves, the vertical wavelengths were in the interquartile range of 9-33 km with a median value of 15 km. The vertical wavelengths are shorter than those observed at Halley station (76°S, 27°W) where the majority of the observed waves were freely propagating. The difference in the wave propagating characteristics between KSS and Halley station suggests that gravity waves may affect mesospheric dynamics in this part of the Antarctic Peninsula more strongly than over the Antarctic continent. Furthermore, strong wind shear over KSS played an important role in changing the vertical wavenumbers as the waves propagated upward between two airglow layers (87 and 96 km). </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JASTP.135..192W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JASTP.135..192W">Spatial gravity wave characteristics obtained from multiple OH(3-1) airglow temperature time series</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Wachter, Paul; Schmidt, Carsten; Wüst, Sabine; Bittner, Michael 2015-12-01 We present a new approach for the detection of gravity waves in OH-airglow observations at the measurement site Oberpfaffenhofen (11.27°E, 48.08°N), Germany. The measurements were performed at the German Remote Sensing Data Center (DFD) of the German Aerospace Center (DLR) during the period from February 4th, 2011 to July 6th, 2011. In this case study the observations were carried out by three identical Ground-based Infrared P-branch Spectrometers (GRIPS). These instruments provide OH(3-1) rotational temperature time series, which enable spatio-temporal investigations of gravity wave characteristics in the mesopause region. The instruments were aligned in such a way that their fields of view (FOV) formed an equilateral triangle in the OH-emission layer at a height of 87 km. The Harmonic Analysis is applied in order to identify joint temperature oscillations in the three individual datasets. Dependent on the specific gravity wave activity in a single night, it is possible to detect up to four different wave patterns with this method. The values obtained for the waves' periods and phases are then used to derive further parameters, such as horizontal wavelength, phase velocity and the direction of propagation. We identify systematic relationships between periods and amplitudes as well as between periods and horizontal wavelengths. A predominant propagation direction towards the East and North-North-East characterizes the waves during the observation period. There are also indications of seasonal effects in the temporal development of the horizontal wavelength and the phase velocity. During late winter and early spring the derived horizontal wavelengths and the phase velocities are smaller than in the subsequent period from early April to July 2011. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/227151-analysis-lyman-alpha-he-angstrom-airglow-measurements-using-spherical-radiative-transfer-model','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/227151-analysis-lyman-alpha-he-angstrom-airglow-measurements-using-spherical-radiative-transfer-model">Analysis of Lyman {alpha} and He I 584-{Angstrom} airglow measurements using a spherical radiative transfer model</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Bush, B.C.; Chakrabarti, S. 1995-10-01 The authors report on the scattering and excitation mechanisms of the terrestrial exospheric H I 1216-{Angstrom} airglow emissions by comparing simulations from a radiative transfer model with spectroscopic measurements from an Earth-orbiting satellite. The purpose of these comparisons are twofold: to assess the sensitivity of the input parameters to the model results and to test the applicability of the model to airglow analysis. The model incorporates a spherically oriented atmosphere to account for the extended scale heights of the exospheric scatterers as well as to properly mimic scattering across the terminator region from the dayside to the nightside hemispheres. Spectroscopicmore » Lyman {alpha} and He I 584 {Angstrom} data were obtained by the STP78-1 satellite that circumnavigated the Earth in a noon/midnight orbit at an altitude of 600 km. The {open_quotes}best fit{close_quotes} analysis of the Lyman {alpha} data acquired on March 25, 1979, requires scaling the hydrogen density distribution obtained from the MSIS-90 (Hedin) atmospheric model by 45-50%, the exospheric temperature by 90-100%, and the Lyman {alpha} solar flux predicted by EUV91 model (Tobiska) by 1.9-2.0. Similar analysis of the He I 584 {Angstrom} data acquired on March 5, 1979, requires scaling the helium density distribution obtained from the MSIS-90 (Hedin) atmospheric model by 60-80% and the exospheric temperature by 105-115% while using a line center 584-{Angstrom} solar flux of 1.44x10{sup 10} photons cm{sup {minus}2}s{sup {minus}1} {Angstrom}{sup {minus}1}. 46 refs., 22 figs., 5 tabs.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3040S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3040S">Airglow at 630 and 557.7 nm during HF pumping of the Ionosphere near the 4th Gyroharmonic at the ``Sura'' Facility in September 2012</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Shindin, Alexey; Nasyrov, Igor; Grach, Savely; Sergeev, Evgeny; Klimenko, Vladimir; Beletsky, Alexandr We present results of artificial optical emission observations in the red (630 nm) and green (557.7 nm) lines of the atomic oxygen during ionosphere HF pumping at the Sura facility (56.1°N, 46.1°E, magnetic field dip angle 71.5°) in Sep. 2012. Pump wave (PW) of O-polarization at frequencies f0 = 4.74 - 5.64 MHz was used in the experiment according to ionospheric conditions after sunset. Two CCD cameras (S1C/079-FP(FU) and KEO Sentinel with fields of view 20° and 145°, respectively, and 3 photometers were used for the emission registration. For estimation of a relation between the PW frequency f0 and 4th electron gyroharmonic 4fce Stimulated Electromagnetic Emission (SEE) registration was applied (for details see [1]). On September 11 the pump beam was inclined by 12° to the South, the PW frequencies f0 = 5.40 and 5.42 MHz were slightly above 4fce. On September 13, for vertical pumping, f0 was 5.64 MHz (well above 4fce), 5.32 - 5.42 MHz (around 4fce) and 4.74 MHz (well below 4fce). On September 14 the vertical pumping at f0 = 5.30 - 5.36 MHz and 4.74 MHz was used. In the latter day due to natural motion of the ionosphere and concurrent SEE measurements we were able to obtain a fine dependence of the optical brightness on the proximity f0 and 4fce. For the red line no essential dependence, as well of the shape and position of the airglow spot on the proximity was obtained with one exception: on Sep. 14 when, according to the SEE spectra, f0 was just below 4fce (by 15-20 kHz), the brightness essentially increased, by 1.25-1.5 times. For the green line, the brightest emission occurred when f0 was passing through 4fce (Sep. 14) and when f0 = 5.64 MHz (Sep. 13, well above 4fce). Also, on Sep. 14 the airglow enhancement in the red line during the pumping was replaced by the suppression of the background emission when the ionosphere critical frequency approached to f0 by less than 500 kHz. Similar effect was obtained on Sep. 11 and in [2] for south-inclined pump beam </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH21A4094P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH21A4094P">Bayesian Analysis Of HMI Solar Image Observables And Comparison To TSI Variations And MWO Image Observables</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Parker, D. G.; Ulrich, R. K.; Beck, J. 2014-12-01 We have previously applied the Bayesian automatic classification system AutoClass to solar magnetogram and intensity images from the 150 Foot Solar Tower at Mount Wilson to identify classes of solar surface features associated with variations in total solar irradiance (TSI) and, using those identifications, modeled TSI time series with improved accuracy (r > 0.96). (Ulrich, et al, 2010) AutoClass identifies classes by a two-step process in which it: (1) finds, without human supervision, a set of class definitions based on specified attributes of a sample of the image data pixels, such as magnetic field and intensity in the case of MWO images, and (2) applies the class definitions thus found to new data sets to identify automatically in them the classes found in the sample set. HMI high resolution images capture four observables-magnetic field, continuum intensity, line depth and line width-in contrast to MWO's two observables-magnetic field and intensity. In this study, we apply AutoClass to the HMI observables for images from May, 2010 to June, 2014 to identify solar surface feature classes. We use contemporaneous TSI measurements to determine whether and how variations in the HMI classes are related to TSI variations and compare the characteristic statistics of the HMI classes to those found from MWO images. We also attempt to derive scale factors between the HMI and MWO magnetic and intensity observables. The ability to categorize automatically surface features in the HMI images holds out the promise of consistent, relatively quick and manageable analysis of the large quantity of data available in these images. Given that the classes found in MWO images using AutoClass have been found to improve modeling of TSI, application of AutoClass to the more complex HMI images should enhance understanding of the physical processes at work in solar surface features and their implications for the solar-terrestrial environment. Ulrich, R.K., Parker, D, Bertello, L. and </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMNH23A0255O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMNH23A0255O">Ionospheric detection of tsunami earthquakes: observation, modeling and ideas for future early warning</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Occhipinti, G.; Manta, F.; Rolland, L.; Watada, S.; Makela, J. J.; Hill, E.; Astafieva, E.; Lognonne, P. H. 2017-12-01 Detection of ionospheric anomalies following the Sumatra and Tohoku earthquakes (e.g., Occhipinti 2015) demonstrated that ionosphere is sensitive to earthquake and tsunami propagation: ground and oceanic vertical displacement induces acoustic-gravity waves propagating within the neutral atmosphere and detectable in the ionosphere. Observations supported by modelling proved that ionospheric anomalies related to tsunamis are deterministic and reproducible by numerical modeling via the ocean/neutral-atmosphere/ionosphere coupling mechanism (Occhipinti et al., 2008). To prove that the tsunami signature in the ionosphere is routinely detected we show here perturbations of total electron content (TEC) measured by GPS and following tsunamigenic earthquakes from 2004 to 2011 (Rolland et al. 2010, Occhipinti et al., 2013), nominally, Sumatra (26 December, 2004 and 12 September, 2007), Chile (14 November, 2007), Samoa (29 September, 2009) and the recent Tohoku-Oki (11 Mars, 2011). Based on the observations close to the epicenter, mainly performed by GPS networks located in Sumatra, Chile and Japan, we highlight the TEC perturbation observed within the first 8 min after the seismic rupture. This perturbation contains information about the ground displacement, as well as the consequent sea surface displacement resulting in the tsunami. In addition to GNSS-TEC observations close to the epicenter, new exciting measurements in the far-field were performed by airglow measurement in Hawaii show the propagation of the internal gravity waves induced by the Tohoku tsunami (Occhipinti et al., 2011). This revolutionary imaging technique is today supported by two new observations of moderate tsunamis: Queen Charlotte (M: 7.7, 27 October, 2013) and Chile (M: 8.2, 16 September 2015). We finally detail here our recent work (Manta et al., 2017) on the case of tsunami alert failure following the Mw7.8 Mentawai event (25 October, 2010), and its twin tsunami alert response following the Mw7 </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active">10</li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active">11</li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170003170&hterms=Situ&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DIn%2BSitu','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170003170&hterms=Situ&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DIn%2BSitu">Simultaneous Observations of Atmospheric Tides from Combined in Situ and Remote Observations at Mars from the MAVEN Spacecraft</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> England, Scott L.; Liu, Guiping; Withers, Paul; Yigit, Erdal; Lo, Daniel; Jain, Sonal; Schneider, Nicholas M. (Inventor); Deighan, Justin; McClintock, William E.; Mahaffy, Paul R.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20170003170'); toggleEditAbsImage('author_20170003170_show'); toggleEditAbsImage('author_20170003170_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20170003170_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20170003170_hide"> 2016-01-01 We report the observations of longitudinal variations in the Martian thermosphere associated with nonmigrating tides. Using the Neutral Gas Ion Mass Spectrometer (NGIMS) and the Imaging Ultraviolet Spectrograph (IUVS) on NASA's Mars Atmosphere and Volatile EvolutioN Mission (MAVEN) spacecraft, this study presents the first combined analysis of in situ and remote observations of atmospheric tides at Mars for overlapping volumes, local times, and overlapping date ranges. From the IUVS observations, we determine the altitude and latitudinal variation of the amplitude of the nonmigrating tidal signatures, which is combined with the NGIMS, providing information on the compositional impact of these waves. Both the observations of airglow from IUVS and the CO2 density observations from NGIMS reveal a strong wave number 2 signature in a fixed local time frame. The IUVS observations reveal a strong latitudinal dependence in the amplitude of the wave number 2 signature. Combining this with the accurate CO2 density observations from NGIMS, this would suggest that the CO2 density variation is as high as 27% at 0-10 deg latitude. The IUVS observations reveal little altitudinal dependence in the amplitude of the wave number 2 signature, varying by only 20% from 160 to 200 km. Observations of five different species with NGIMS show that the amplitude of the wave number 2 signature varies in proportion to the inverse of the species scale height, giving rise to variation in composition as a function of longitude. The analysis and discussion here provide a roadmap for further analysis as additional coincident data from these two instruments become available. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss039e009160.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss039e009160.html">Earth Observations taken by the Expedition 39 Crew</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2014-04-02 ISS039-E-009160 (2 April 2014) --- This nighttime view featuring the aurora borealis, the moon and Moscow was photographed by an Expedition 39 crew member on the International Space Station. A thin green line of the aurora borealis crosses the top of this image. The moon appears as a white disc just above the aurora. Airglow appears as a blue-white cusp on Earth's limb. Russia's capital city Moscow makes a splash of yellow (lower left), with its easily recognized radial pattern of highways. Other cities are Nizhni Novgorod (lower center) 400 kilometers from Moscow, St. Petersburg (left) 625 kilometers from Moscow, and Finland?s capital city Helsinki. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.2681S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.2681S">Observation sequences and onboard data processing of Planet-C</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Suzuki, M.; Imamura, T.; Nakamura, M.; Ishi, N.; Ueno, M.; Hihara, H.; Abe, T.; Yamada, T. Planet-C or VCO Venus Climate Orbiter will carry 5 cameras IR1 IR 1micrometer camera IR2 IR 2micrometer camera UVI UV Imager LIR Long-IR camera and LAC Lightning and Airglow Camera in the UV-IR region to investigate atmospheric dynamics of Venus During 30 hr orbiting designed to quasi-synchronize to the super rotation of the Venus atmosphere 3 groups of scientific observations will be carried out i image acquisition of 4 cameras IR1 IR2 UVI LIR 20 min in 2 hrs ii LAC operation only when VCO is within Venus shadow and iii radio occultation These observation sequences will define the scientific outputs of VCO program but the sequences must be compromised with command telemetry downlink and thermal power conditions For maximizing science data downlink it must be well compressed and the compression efficiency and image quality have the significant scientific importance in the VCO program Images of 4 cameras IR1 2 and UVI 1Kx1K and LIR 240x240 will be compressed using JPEG2000 J2K standard J2K is selected because of a no block noise b efficiency c both reversible and irreversible d patent loyalty free and e already implemented as academic commercial software ICs and ASIC logic designs Data compression efficiencies of J2K are about 0 3 reversible and 0 1 sim 0 01 irreversible The DE Digital Electronics unit which controls 4 cameras and handles onboard data processing compression is under concept design stage It is concluded that the J2K data compression logics circuits using space </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSA21B..01M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSA21B..01M">Imaging, radio, and modeling results pertaining to the ionospheric signature of the 11 March 2011 tsunami over the Pacific Ocean</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Makela, J. J.; Lognonne, P.; Occhipinti, G.; Hebert, H.; Gehrels, T.; Coisson, P.; Rolland, L. M.; Allgeyer, S.; Kherani, A. 2011-12-01 The Mw=9.0 earthquake that occurred off the east coast of Honshu, Japan on 11 March 2011 launched a tsunami that traveled across the Pacific Ocean, in turn launching vertically propagating atmospheric gravity waves. Upon reaching 250-350 km in altitude, these waves impressed their signature on the thermosphere/ionosphere system. We present observations of this signature obtained using a variety of radio instruments and an imaging system located on the islands of Hawaii. These measurements represent the first optical images recorded of the airglow signature resulting from the passage of a tsunami. Results from these instruments clearly show wave structure propagating in the upper atmosphere with the same velocity as the ocean tsunami, emphasizing the coupled nature of the ocean, atmosphere, and ionosphere. Modeling results are also presented to highlight current understandings of this coupling process. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Ap%26SS.363...83S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Ap%26SS.363...83S">Study of equatorial plasma bubbles using all sky imager and scintillation technique from Kolhapur station: a case study</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sharma, A. K.; Gurav, O. B.; Gaikwad, H. P.; Chavan, G. A.; Nade, D. P.; Nikte, S. S.; Ghodpage, R. N.; Patil, P. T. 2018-04-01 The nightglow observations of OI 630.0 nm emission carried out from low latitude station Kolhapur using All Sky Imager (ASI) with 140° field of view (FOV) for the month of April 2011 are used. The images were processed to study the field aligned irregularities often called as equatorial plasma bubbles (EPBs). The present study focuses on the occurrence of scintillation during the traversal of EPBs over ionospheric pierce point (IPP). Here we dealt with the depletion level (depth) of the EPB structures and its effect on VHF signals. We compared VHF scintillation data with airglow intensities at Ionospheric pierce point (IPP) from the same location and found that the largely depleted EPBs make stronger scintillation. From previous literature, it is believed that the small scale structures are present near the steeper walls of EPBs which often degrades the communication, the analysis presented in this paper confirms this belief. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990009871&hterms=monographs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmonographs','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990009871&hterms=monographs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmonographs">Auroral Observations from the POLAR Ultraviolet Imager (UVI)</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Germany, G. A.; Spann, J. F.; Parks, G. K.; Brittnacher, M. J.; Elsen, R.; Chen, L.; Lummerzheim, D.; Rees, M. H. 1998-01-01 Because of the importance of the auroral regions as a remote diagnostic of near-Earth plasma processes and magnetospheric structure, spacebased instrumentation for imaging the auroral regions have been designed and operated for the last twenty-five years. The latest generation of imagers, including those flown on the POLAR satellite, extends this quest for multispectral resolution by providing three separate imagers for the visible, ultraviolet, and X ray images of the aurora. The ability to observe extended regions allows imaging missions to significantly extend the observations available from in situ or groundbased instrumentation. The complementary nature of imaging and other observations is illustrated below using results from tile GGS Ultraviolet Imager (UVI). Details of the requisite energy and intensity analysis are also presented. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930017596','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930017596">Ultraviolet Imaging Telescope (UIT) observations of galaxies</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Neff, S. G. 1993-01-01 Ultraviolet images of several galaxies were obtained during the ASTRO-1 shuttle mission in December, 1990. The images have a FWHM angular resolution of approximately 3 arcsecond and are of circular fields approximately 40 arcminutes in diameter. Most galaxies were observed in at least two and sometimes as many as four broad bands. A very few fields were observed with narrower band filters. The most basic result of these observations is that most systems look dramatically different in the UV from their well-known optical appearances. Preliminary results of these studies will be presented. Information will be available on fields observed by the UTI during the ASTRO 1 mission; when that data becomes public it can be obtained from the NSSDC. The ASTRO observatory is expected to fly again in 1994 with approximately half of the observing time from that mission devoted to guest observers. The Ultraviolet Imaging telescope is extremely well suited for galaxy studies, and the UIT term is interested in encouraging a wide range of scientific studies by guest observers. Ultraviolet Imaging telescope is extremely well suited for galaxy studies, and the UIT team is interested in encouraging a wide range of scientific studies by guest observers. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA13B..05Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA13B..05Y">Interhemispheric Asymmetry in the Mesosphere and Lower Thermosphere Observed by SABER/TIMED</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Yee, J. H. 2017-12-01 In this paper we analyze nearly 15 years of satellite observations of temperature, airglow, and composition in the Mesosphere and Lower Thermosphere (MLT) to quantify their interhemispheric asymmetries ao one can provide quantitative links between observed asymmetries and the spatial and temporal variations of the gravity wave activity. Two processes are believed to be responsible for observed interhemispheric differences in the MLT. The first is the direct radiation effect from the eccentricity of the Earth orbit amd the other is the difference in gravity wave source distribution and filtering due to asymmetries in mean winds of the lower atmosphere. Both processes have been theoretically investigated to explain the observed asymmetry in some of the atmospheric parameters, but not self-consistently in all observed parameters together. In this paper we will show the asymmetry in the time-varying zonal-mean latitudinal structures of temperature, airglow emission rate, and composition observed by TIMED/SABER. We will quantify their interhemispheric asymmetries for different seasons under different solar activity conditions. In addition, temperature measurements will also be used to obtain temporal and spatial morphology of gravity wave potential energies. We will interpret the asymmetry in the observed fields and examine qualitatively their consistency with the two responsible processes, especially the one due to gravity wave filtering process. Our goal is to introduce and to share the spatial and temporal morphologies of all the observed fields to the modeling community so, together self-consistently, they be can be used to gain physical insights into the relative importance of various drivers responsible for the observed asymmetry, especially the role of gravity wave induced eddy drag and mixing, a critical, but least quantitatively understood process. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22069179-ray-phase-imaging-from-static-observation-dynamic-observation','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22069179-ray-phase-imaging-from-static-observation-dynamic-observation">X-ray phase imaging-From static observation to dynamic observation-</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Momose, A.; Yashiro, W.; Olbinado, M. P. 2012-07-31 We are attempting to expand the technology of X-ray grating phase imaging/tomography to enable dynamic observation. X-ray phase imaging has been performed mainly for static cases, and this challenge is significant since properties of materials (and hopefully their functions) would be understood by observing their dynamics in addition to their structure, which is an inherent advantage of X-ray imaging. Our recent activities in combination with white synchrotron radiation for this purpose are described. Taking advantage of the fact that an X-ray grating interferometer functions with X-rays of a broad energy bandwidth (and therefore high flux), movies of differential phase imagesmore » and visibility images are obtained with a time resolution of a millisecond. The time resolution of X-ray phase tomography can therefore be a second. This study is performed as a part of a project to explore X-ray grating interferometry, and our other current activities are also briefly outlined.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JASS...31..169J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JASS...31..169J">Ground-based Observations for the Upper Atmosphere at King Sejong Station, Antarctica</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Jee, Geonhwa; Kim, Jeong-Han; Lee, Changsup; Kim, Yong Ha 2014-06-01 Since the operation of the King Sejong Station (KSS) started in Antarctic Peninsula in 1989, there have been continuous efforts to perform the observation for the upper atmosphere. The observations during the initial period of the station include Fabry-Perot Interferometer (FPI) and Michelson Interferometer for the mesosphere and thermosphere, which are no longer in operation. In 2002, in collaboration with York University, Canada, the Spectral Airglow Temperature Imager (SATI) was installed to observe the temperature in the mesosphere and lower thermosphere (MLT) region and it has still been producing the mesopause temperature data until present. The observation was extended by installing the meteor radar in 2007 to observe the neutral winds and temperature in the MLT region during the day and night in collaboration with Chungnam National University. We also installed the all sky camera in 2008 to observe the wave structures in the MLT region. All these observations are utilized to study on the physical characteristics of the MLT region and also on the wave phenomena such as the tide and gravity wave in the upper atmosphere over KSS that is well known for the strong gravity wave activity. In this article, brief introductions for the currently operating instruments at KSS will be presented with their applications for the study of the upper atmosphere </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSA23A2379C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSA23A2379C">Analysis of TIMED/GUVI Dayglow Utraviolet Oxygen Images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Christensen, A. B.; Crowley, G.; Meier, R. 2016-12-01 Analysis of the atomic oxygen resonance transition at 130.4 nm and the inter-combination transition at 135.6 nm measured by the TIMED/GUVI mission demonstrates the state of knowledge of these important dayglow emission features and the degree to which current models can simulate their global properties. The complete modeling framework comprises several models, including the Thermosphere ionosphere Mesosphere Electrodynamics General Circulation Model (TIME-GCM), Assimilative Mapping of Ionospheric Electrodynamics (AMIE), a partial frequency redistribution resonance scattering model usually called REDISTER needed to compute the optically thick radiative transfer of the 130.4 nm emission, airglow emission models, GLOW and AURIC and other procedures. Observations for four different days, collected under different geophysical conditions of magnetic activity and solar cycle, show very good agreement with the calculated emission brightness and geographic distribution for both emissions. The differences between the airglow codes for the 135.6 nm emission will be discussed in connection to the photoelectron energy loss cross sections, as well as the excitation cross sections used in the various models. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15839266','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15839266">Multifacet structure of observed reconstructed integral images.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Martínez-Corral, Manuel; Javidi, Bahram; Martínez-Cuenca, Raúl; Saavedra, Genaro 2005-04-01 Three-dimensional images generated by an integral imaging system suffer from degradations in the form of grid of multiple facets. This multifacet structure breaks the continuity of the observed image and therefore reduces its visual quality. We perform an analysis of this effect and present the guidelines in the design of lenslet imaging parameters for optimization of viewing conditions with respect to the multifacet degradation. We consider the optimization of the system in terms of field of view, observer position and pupil function, lenslet parameters, and type of reconstruction. Numerical tests are presented to verify the theoretical analysis. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.8134F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.8134F">The Imager for Sprites and Upper Atmospheric Lightning (ISUAL)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Frey, H. U.; Mende, S. B.; Harris, S. E.; Heetderks, H.; Takahashi, Y.; Su, H.-T.; Hsu, R.-R.; Chen, A. B.; Fukunishi, H.; Chang, Y.-S.; Lee, L.-C. 2016-08-01 The Imager for Sprites and Upper Atmospheric Lightning (ISUAL) was the first specifically dedicated instrument to observe lightning-induced transient luminous events (TLE): sprites, elves, halos, and gigantic jets from space. The Imager is an intensified CCD system operating in the visible wavelength region with a filter wheel to select from six positions with filters. The Imager has a 5° × 20° (vertical times horizontal) field of view. The spectrophotometer (SP) is populated with six photometers with individual filters for emissions from the far ultraviolet to the near infrared. An array photometer with two channels operating in the blue and red provides altitude profiles of the emission over 16 altitude bins each. The Associated Electronics Package (AEP) controls instrument functions and interfaces with the spacecraft. ISUAL was launched 21 May 2004 into a Sun-synchronous 890 km orbit on the Formosat-2 satellite and has successfully been collecting data ever since. ISUAL is running on the nightside of the orbit and is pointed to the east of the orbit down toward the limb. The instrument runs continuously and writes data to a circular buffer. Whenever the SP detects a sudden signal increase above a preset threshold, a trigger signal is generated that commands the system to keep the data for about 400 ms starting from ~50 ms before the trigger. Over its lifetime of ~11 years the system recorded thousands of TLE and also successfully observed aurora and airglow. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4851511R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4851511R">Chapman Solar Zenith Angle variations at Titan</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Royer, Emilie M.; Ajello, Joseph; Holsclaw, Gregory; West, Robert; Esposito, Larry W.; Bradley, Eric Todd 2016-10-01 Solar XUV photons and magnetospheric particles are the two main sources contributing to the airglow in the Titan's upper atmosphere. We are focusing here on the solar XUV photons and how they influence the airglow intensity. The Cassini-UVIS observations analyzed in this study consist each in a partial scan of Titan, while the center of the detector stays approximately at the same location on Titan's disk. We used observations from 2008 to 2012, which allow for a wide range of Solar Zenith Angle (SZA). Spectra from 800 km to 1200 km of altitude have been corrected from the solar spectrum using TIMED/SEE data. We observe that the airglow intensity varies as a function of the SZA and follows a Chapman curve. Three SZA regions are identified: the sunlit region ranging from 0 to 50 degrees. In this region, the intensity of the airglow increases, while the SZA decreases. Between SZA 50 and 100 degrees, the airglow intensity decreases from it maximum to its minimum. In this transition region the upper atmosphere of Titan changes from being totally sunlit to being in the shadow of the moon. For SZA 100 to 180 degrees, we observe a constant airglow intensity close to zero. The behavior of the airglow is also similar to the behavior of the electron density as a function of the SZA as observed by Ågren at al (2009). Both variables exhibit a decrease intensity with increasing SZA. The goal of this study is to understand such correlation. We demonstrate the importance of the solar XUV photons contribution to the Titan airglow and prove that the strongest contribution to the Titan dayglow occurs by solar fluorescence rather than the particle impact that predominates at night. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ACP....17.4177U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ACP....17.4177U">Measuring FeO variation using astronomical spectroscopic observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Unterguggenberger, Stefanie; Noll, Stefan; Feng, Wuhu; Plane, John M. C.; Kausch, Wolfgang; Kimeswenger, Stefan; Jones, Amy; Moehler, Sabine 2017-03-01 Airglow emission lines of OH, O2, O and Na are commonly used to probe the MLT (mesosphere-lower thermosphere) region of the atmosphere. Furthermore, molecules like electronically excited NO, NiO and FeO emit a (pseudo-) continuum. These continua are harder to investigate than atomic emission lines. So far, limb-sounding from space and a small number of ground-based low-to-medium resolution spectra have been used to measure FeO emission in the MLT. In this study the medium-to-high resolution echelle spectrograph X-shooter at the Very Large Telescope (VLT) in the Chilean Atacama Desert (24°37' S, 70°24' W; 2635 m) is used to study the FeO pseudo-continuum in the range from 0.5 to 0.72 µm based on 3662 spectra. Variations of the FeO spectrum itself, as well as the diurnal and seasonal behaviour of the FeO and Na emission intensities, are reported. These airglow emissions are linked by their common origin, meteoric ablation, and they share O3 as a common reactant. Major differences are found in the main emission peak of the FeO airglow spectrum between 0.58 and 0.61 µm, compared with a theoretical spectrum. The FeO and Na airglow intensities exhibit a similar nocturnal variation and a semi-annual seasonal variation with equinoctial maxima. This is satisfactorily reproduced by a whole atmosphere chemistry climate model, if the quantum yields for the reactions of Fe and Na with O3 are 13 ± 3 and 11 ± 2 % respectively. However, a comparison between the modelled O3 in the upper mesosphere and measurements of O3 made with the SABER satellite instrument suggests that these quantum yields may be a factor of ˜ 2 smaller. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018GeoRL..45...15G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018GeoRL..45...15G">Predicting Electron Population Characteristics in 2-D Using Multispectral Ground-Based Imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Grubbs, Guy; Michell, Robert; Samara, Marilia; Hampton, Donald; Jahn, Jorg-Micha 2018-01-01 Ground-based imaging and in situ sounding rocket data are compared to electron transport modeling for an active inverted-V type auroral event. The Ground-to-Rocket Electrodynamics-Electrons Correlative Experiment (GREECE) mission successfully launched from Poker Flat, Alaska, on 3 March 2014 at 11:09:50 UT and reached an apogee of approximately 335 km over the aurora. Multiple ground-based electron-multiplying charge-coupled device (EMCCD) imagers were positioned at Venetie, Alaska, and aimed toward magnetic zenith. The imagers observed the intensity of different auroral emission lines (427.8, 557.7, and 844.6 nm) at the magnetic foot point of the rocket payload. Emission line intensity data are correlated with electron characteristics measured by the GREECE onboard electron spectrometer. A modified version of the GLobal airglOW (GLOW) model is used to estimate precipitating electron characteristics based on optical emissions. GLOW predicted the electron population characteristics with 20% error given the observed spectral intensities within 10° of magnetic zenith. Predictions are within 30% of the actual values within 20° of magnetic zenith for inverted-V-type aurora. Therefore, it is argued that this technique can be used, at least in certain types of aurora, such as the inverted-V type presented here, to derive 2-D maps of electron characteristics. These can then be used to further derive 2-D maps of ionospheric parameters as a function of time, based solely on multispectral optical imaging data. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930047925&hterms=iso&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Diso','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930047925&hterms=iso&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Diso">Mesospheric nightglow spectral survey taken by the ISO spectral spatial imager on ATLAS 1</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Owens, J. K.; Torr, D. G.; Torr, M. R.; Chang, T.; Fennelly, J. A.; Richards, P. G.; Morgan, M. F.; Baldridge, T. W.; Fellows, C. W.; Dougani, H. 1993-01-01 This paper reports the first comprehensive spectral survey of the mesospheric airglow between 260 and 832 nm taken by the Imaging Spectrometric Observatory on the ATLAS 1 mission. We select data taken in the spectral window between 275 and 300 nm to determine the variation with altitude of the Herzberg I bands originating from the vibrational levels v-prime = 3 to 8. These data provide the first spatially resolved spectral measurements of the system. The data are used to demonstrate that to within an uncertainty of +/- 10 percent, the vibrational distribution remains invariant with altitude. The deficit reported previously for the v-prime = 5 level is not observed although there is a suggestion of depletion in v-prime = 6. The data could be used to place tight constraints on the vibrational dependence of quenching rate coefficients, and on the abundance of atomic oxygen. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960029055&hterms=iso&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Diso','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960029055&hterms=iso&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Diso">Mesospheric nightglow spectral survey taken by the ISO spectral spatial imager on Atlas 1</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Owens, J. K.; Torr, D. G.; Torr, M. R.; Chang, T.; Fennelly, J. A.; Richards, P. G.; Morgan, M. F.; Baldridge, T. W.; Dougani, H.; Swift, W. 1993-01-01 This paper reports the first comprehensive spectral survey of the mesospheric airglow between 260 and 832 nm taken by the Imaging Spectrometric Observatory (ISO) on the ATLAS I mission. We select data taken in the spectral window between 275 and 300 nm to determine the variation with altitude of the Herzberg I bands originating from the vibrational levels v' = 3 to 8. These data provide the first spatially resolved spectral measurements of the system. The data are used to demonstrate that to within an uncertainty of + 10%, the vibrational distribution remains invariant with altitude. The deficit reported previously for the v' = 5 level is not observed although there is a suggestion of depletion in v' = 6. The data could be used to place tight constraints on the vibrational dependence of quenching rate coefficients, and on the abundance of atomic oxygen. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7710E..0NB','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7710E..0NB">Dynamic image fusion and general observer preference</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Burks, Stephen D.; Doe, Joshua M. 2010-04-01 Recent developments in image fusion give the user community many options for ways of presenting the imagery to an end-user. Individuals at the US Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate have developed an electronic system that allows users to quickly and efficiently determine optimal image fusion algorithms and color parameters based upon collected imagery and videos from environments that are typical to observers in a military environment. After performing multiple multi-band data collections in a variety of military-like scenarios, different waveband, fusion algorithm, image post-processing, and color choices are presented to observers as an output of the fusion system. The observer preferences can give guidelines as to how specific scenarios should affect the presentation of fused imagery. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611013J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611013J">A new technique for measuring aerosols with moonlight observations and a sky background model</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Jones, Amy; Noll, Stefan; Kausch, Wolfgang; Kimeswenger, Stefan; Szyszka, Ceszary; Unterguggenberger, Stefanie 2014-05-01 There have been an ample number of studies on aerosols in urban, daylight conditions, but few for remote, nocturnal aerosols. We have developed a new technique for investigating such aerosols using our sky background model and astronomical observations. With a dedicated observing proposal we have successfully tested this technique for nocturnal, remote aerosol studies. This technique relies on three requirements: (a) sky background model, (b) observations taken with scattered moonlight, and (c) spectrophotometric standard star observations for flux calibrations. The sky background model was developed for the European Southern Observatory and is optimized for the Very Large Telescope at Cerro Paranal in the Atacama desert in Chile. This is a remote location with almost no urban aerosols. It is well suited for studying remote background aerosols that are normally difficult to detect. Our sky background model has an uncertainty of around 20 percent and the scattered moonlight portion is even more accurate. The last two requirements are having astronomical observations with moonlight and of standard stars at different airmasses, all during the same night. We had a dedicated observing proposal at Cerro Paranal with the instrument X-Shooter to use as a case study for this method. X-Shooter is a medium resolution, echelle spectrograph which covers the wavelengths from 0.3 to 2.5 micrometers. We observed plain sky at six different distances (7, 13, 20, 45, 90, and 110 degrees) to the Moon for three different Moon phases (between full and half). Also direct observations of spectrophotometric standard stars were taken at two different airmasses for each night to measure the extinction curve via the Langley method. This is an ideal data set for testing this technique. The underlying assumption is that all components, other than the atmospheric conditions (specifically aerosols and airglow), can be calculated with the model for the given observing parameters. The scattered </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active">11</li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active">12</li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E2022V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E2022V">First retrievals of MLT sodium profiles based on satellite sodium nightglow observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Von Savigny, Christian; Zilker, Bianca; Langowski, Martin 2016-07-01 The Na D lines are a well known feature of the terrestrial airglow and have been identified for the first time in 1929. During the daytime the Na airglow emission is caused by resonance fluorescence, while during the night the excitation occurs by chemiluminescent reactions. Knowledge of Na in the mesopause region is of interest, because the Na layer is thought to be maintained by meteoric ablation and Na measurements allow constraining the meteoric mass influx into the Earth system. In this contribution we employ SCIAMACHY/Envisat nighttime limb measurements of the Na D-line airglow from fall 2002 to spring 2012 - in combination with photochemical models - in order to retrieve Na concentration profiles in the 75 - 100 km altitude range. The Na profiles show realistic peak altitudes, number densities and seasonal variations. The retrieval scheme, sample results and comparisons to ground-based LIDAR measurements of Na as well as SCIAMACHY daytime retrievals will be presented. Moreover, uncertainties in the assumed photochemical scheme and their impact on the Na retrievals will be discussed. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA43B2658S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA43B2658S">Improved Background Removal in Sounding Rocket Neutral Atom Imaging Data</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Smith, M. R.; Rowland, D. E. 2017-12-01 The VISIONS sounding rocket, launched into a substorm on Feb 7, 2013 from Poker Flat, Alaska had a novel miniaturized energetic neutral atom (ENA) imager onboard. We present further analysis of the ENA data from this rocket flight, including improved removal of ultraviolet and electron contamination. In particular, the relative error source contributions due to geocoronal, auroral, and airglow UV, as well as energetic electrons from 10 eV to 3 keV were assessed. The resulting data provide a more clear understanding of the spatial and temporal variations of the ion populations that are energized to tens or hundreds of eV. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080015493','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080015493">SABER Observations of the OH Meinel Airglow Variability Near the Mesopause</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Marsh, Daniel R.; Smith, Anne K.; Mlynczak, Martin G. 2005-01-01 The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, one of four on board the TIMED satellite, observes the OH Meinel emission at 2.0 m that peaks near the mesopause. The emission results from reactions between members of the oxygen and hydrogen chemical families that can be significantly affected by mesopause dynamics. In this study we compare SABER measurements of OH Meinel emission rates and temperatures with predictions from a 3-dimensional chemical dynamical model. In general, the model is capable of reproducing both the observed diurnal and seasonal OH Meinel emission variability. The results indicate that the diurnal tide has a large effect on the overall magnitude and temporal variation of the emission in low latitudes. This tidal variability is so dominant that the seasonal cycle in the nighttime emission depends very strongly on the local time of the analysis. At higher latitudes, the emission has an annual cycle that is due mainly to transport of oxygen by the seasonally reversing mean circulation. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030068415&hterms=Plasma+Ring&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPlasma%2BRing','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030068415&hterms=Plasma+Ring&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPlasma%2BRing">IMAGE Observations of Plasmasphere/Ring Current Interactions</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Gallagher, D. L.; Adrian, M. L.; Perez, J.; Sandel, B. R. 2003-01-01 Evidence has been found in IMAGE observations that overlap of the plasmasphere and the ring current may lead to enhanced loss of plasma into the ionosphere. It has long been anticipated that this mixing of plasma leads to coupling and resulting consequences on both populations. Wave generation, pitch angle scattering, and heating are some of the consequences that are anticipated. IMAGE plasmasphere ring current, and auroral observations will be presented and used to explore these interactions and their effects. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1910580R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1910580R">Magnetospheric particle precipitation at Titan</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Royer, Emilie; Esposito, Larry; Crary, Frank; Wahlund, Jan-Erik 2017-04-01 Although solar XUV radiation is known to be the main source of ionization in Titan's upper atmosphere around 1100 km of altitude, magnetospheric particle precipitation can also account for about 10% of the ionization process. Magnetospheric particle precipitation is expected to be the most intense on the nightside of the satelllite and when Titan's orbital position around Saturn is the closest to Noon Saturn Local Time (SLT). In addition, on several occasion throughout the Cassini mission, Titan has been observed while in the magnetosheath. We are reporting here Ultraviolet (UV) observations of Titan airglow enhancements correlated to these magnetospheric changing conditions occurring while the spacecraft, and thus Titan, are known to have crossed Saturn's magnetopause and have been exposed to the magnetosheath environnment. Using Cassini-Ultraviolet Imaging Spectrograph (UVIS) observations of Titan around 12PM SLT as our primary set of data, we present evidence of Titan's upper atmosphere response to a fluctuating magnetospheric environment. Pattern recognition software based on 2D UVIS detector images has been used to retrieve observations of interest, looking for airglow enhancement of a factor of 2. A 2D UVIS detector image, created for each UVIS observation of Titan, displays the spatial dimension of the UVIS slit on the x-axis and the time on the y-axis. In addition, data from the T32 flyby and from April 17, 2005 from in-situ Cassini instruments are used. Correlations with data from simultaneous observations of in-situ Cassini instruments (CAPS, RPWS and MIMI) has been possible on few occasions and events such as electron burst and reconnections can be associated with unusual behaviors of the Titan airglow. CAPS in-situ measurements acquired during the T32 flyby are consistent with an electron burst observed at the spacecraft as the cause of the UV emission. Moreover, on April 17, 2005 the UVIS observation displays feature similar to what could be a </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23453000','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23453000">Quantification of heterogeneity observed in medical images.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Brooks, Frank J; Grigsby, Perry W 2013-03-02 There has been much recent interest in the quantification of visually evident heterogeneity within functional grayscale medical images, such as those obtained via magnetic resonance or positron emission tomography. In the case of images of cancerous tumors, variations in grayscale intensity imply variations in crucial tumor biology. Despite these considerable clinical implications, there is as yet no standardized method for measuring the heterogeneity observed via these imaging modalities. In this work, we motivate and derive a statistical measure of image heterogeneity. This statistic measures the distance-dependent average deviation from the smoothest intensity gradation feasible. We show how this statistic may be used to automatically rank images of in vivo human tumors in order of increasing heterogeneity. We test this method against the current practice of ranking images via expert visual inspection. We find that this statistic provides a means of heterogeneity quantification beyond that given by other statistics traditionally used for the same purpose. We demonstrate the effect of tumor shape upon our ranking method and find the method applicable to a wide variety of clinically relevant tumor images. We find that the automated heterogeneity rankings agree very closely with those performed visually by experts. These results indicate that our automated method may be used reliably to rank, in order of increasing heterogeneity, tumor images whether or not object shape is considered to contribute to that heterogeneity. Automated heterogeneity ranking yields objective results which are more consistent than visual rankings. Reducing variability in image interpretation will enable more researchers to better study potential clinical implications of observed tumor heterogeneity. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2859675','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2859675">Spatio-temporal Hotelling observer for signal detection from image sequences</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Caucci, Luca; Barrett, Harrison H.; Rodríguez, Jeffrey J. 2010-01-01 Detection of signals in noisy images is necessary in many applications, including astronomy and medical imaging. The optimal linear observer for performing a detection task, called the Hotelling observer in the medical literature, can be regarded as a generalization of the familiar prewhitening matched filter. Performance on the detection task is limited by randomness in the image data, which stems from randomness in the object, randomness in the imaging system, and randomness in the detector outputs due to photon and readout noise, and the Hotelling observer accounts for all of these effects in an optimal way. If multiple temporal frames of images are acquired, the resulting data set is a spatio-temporal random process, and the Hotelling observer becomes a spatio-temporal linear operator. This paper discusses the theory of the spatio-temporal Hotelling observer and estimation of the required spatio-temporal covariance matrices. It also presents a parallel implementation of the observer on a cluster of Sony PLAYSTATION 3 gaming consoles. As an example, we consider the use of the spatio-temporal Hotelling observer for exoplanet detection. PMID:19550494 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19550494','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19550494">Spatio-temporal Hotelling observer for signal detection from image sequences.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Caucci, Luca; Barrett, Harrison H; Rodriguez, Jeffrey J 2009-06-22 Detection of signals in noisy images is necessary in many applications, including astronomy and medical imaging. The optimal linear observer for performing a detection task, called the Hotelling observer in the medical literature, can be regarded as a generalization of the familiar prewhitening matched filter. Performance on the detection task is limited by randomness in the image data, which stems from randomness in the object, randomness in the imaging system, and randomness in the detector outputs due to photon and readout noise, and the Hotelling observer accounts for all of these effects in an optimal way. If multiple temporal frames of images are acquired, the resulting data set is a spatio-temporal random process, and the Hotelling observer becomes a spatio-temporal linear operator. This paper discusses the theory of the spatio-temporal Hotelling observer and estimation of the required spatio-temporal covariance matrices. It also presents a parallel implementation of the observer on a cluster of Sony PLAYSTATION 3 gaming consoles. As an example, we consider the use of the spatio-temporal Hotelling observer for exoplanet detection. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080037618&hterms=negev+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnegev%2Bradiation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080037618&hterms=negev+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnegev%2Bradiation">Plasmaspheric Plumes Observed by the CLUSTER and IMAGE Spacecraft</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Fung, S. F.; Benson, R. F.; Garcia, L. N.; Adrian, M. L.; Sandel, B.; Goldstein, M. L. 2008-01-01 Global IMAGE/EUV observations have revealed complex changes in plasmaspheric structures as the plasmasphere responds to geomagnetic activity while remaining under varying degrees of influence by co-rotation, depending on the radial distance. The complex plasmaspheric dynamics, with different scales of variability, is clearly far from being well understood. There is now renewed interest in the plasmasphere due to its apparent connections with the development of the ring current and radiation belt, and loss of ionospheric plasmas. Early in the mission, the Cluster spacecraft only crossed the plasmapause (L - 4) occasionally and made measurements of the outer plasmasphere and plasmaspheric drainage plumes. The study by Darrouzet et al. [2006] provided detailed analyses of in situ Cluster observations and IMAGE EUV observations of three plasmaspheric plumes detected in April-June, 2002. Within the next couple of years, Cluster orbit will change, causing perigee to migrate to lower altitudes, and thus providing excellent opportunities to obtain more detailed measurements of the plasmasphere. In this paper, we report our analyses of the earlier Cluster-IMAGE events by incorporating the different perspectives provided by the IMAGE Radio Plasma Imager (RPI) observations. We will discuss our new understanding of the structure and dynamics of the Cluster-IMAGE events. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17730507','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17730507">One Mars year: viking lander imaging observations.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Jones, K L; Arvidson, R E; Guinness, E A; Bragg, S L; Wall, S D; Carlston, C E; Pidek, D G 1979-05-25 Throughout the complete Mars year during which they have been on the planet, the imaging systems aboard the two Viking landers have documented a variety of surface changes. Surface condensates, consisting of both solid H(2)O and CO(2), formed at the Viking 2 lander site during the winter. Additional observations suggest that surface erosion rates due to dust redistribution may be substantially less than those predicted on the basis of pre-Viking observations. The Viking 1 lander will continue to acquire and transmit a predetermined sequence of imaging and meteorology data as long as it is operative. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22220517-correlation-between-model-observer-human-observer-performance-ct-imaging-when-lesion-location-uncertain','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22220517-correlation-between-model-observer-human-observer-performance-ct-imaging-when-lesion-location-uncertain">Correlation between model observer and human observer performance in CT imaging when lesion location is uncertain</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Leng, Shuai; Yu, Lifeng; Zhang, Yi 2013-08-15 Purpose: The purpose of this study was to investigate the correlation between model observer and human observer performance in CT imaging for the task of lesion detection and localization when the lesion location is uncertain.Methods: Two cylindrical rods (3-mm and 5-mm diameters) were placed in a 35 × 26 cm torso-shaped water phantom to simulate lesions with −15 HU contrast at 120 kV. The phantom was scanned 100 times on a 128-slice CT scanner at each of four dose levels (CTDIvol = 5.7, 11.4, 17.1, and 22.8 mGy). Regions of interest (ROIs) around each lesion were extracted to generate imagesmore » with signal-present, with each ROI containing 128 × 128 pixels. Corresponding ROIs of signal-absent images were generated from images without lesion mimicking rods. The location of the lesion (rod) in each ROI was randomly distributed by moving the ROIs around each lesion. Human observer studies were performed by having three trained observers identify the presence or absence of lesions, indicating the lesion location in each image and scoring confidence for the detection task on a 6-point scale. The same image data were analyzed using a channelized Hotelling model observer (CHO) with Gabor channels. Internal noise was added to the decision variables for the model observer study. Area under the curve (AUC) of ROC and localization ROC (LROC) curves were calculated using a nonparametric approach. The Spearman's rank order correlation between the average performance of the human observers and the model observer performance was calculated for the AUC of both ROC and LROC curves for both the 3- and 5-mm diameter lesions.Results: In both ROC and LROC analyses, AUC values for the model observer agreed well with the average values across the three human observers. The Spearman's rank order correlation values for both ROC and LROC analyses for both the 3- and 5-mm diameter lesions were all 1.0, indicating perfect rank ordering agreement of the figures of merit (AUC) between </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5606269','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5606269">A new method to evaluate image quality of CBCT images quantitatively without observers</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Shimizu, Mayumi; Okamura, Kazutoshi; Yoshida, Shoko; Weerawanich, Warangkana; Tokumori, Kenji; Jasa, Gainer R; Yoshiura, Kazunori 2017-01-01 Objectives: To develop an observer-free method for quantitatively evaluating the image quality of CBCT images by applying just-noticeable difference (JND). Methods: We used two test objects: (1) a Teflon (polytetrafluoroethylene) plate phantom attached to a dry human mandible; and (2) a block phantom consisting of a Teflon step phantom and an aluminium step phantom. These phantoms had holes with different depths. They were immersed in water and scanned with a CB MercuRay (Hitachi Medical Corporation, Tokyo, Japan) at tube voltages of 120 kV, 100 kV, 80 kV and 60 kV. Superimposed images of the phantoms with holes were used for evaluation. The number of detectable holes was used as an index of image quality. In detecting holes quantitatively, the threshold grey value (ΔG), which differentiated holes from the background, was calculated using a specific threshold (the JND), and we extracted the holes with grey values above ΔG. The indices obtained by this quantitative method (the extracted hole values) were compared with the observer evaluations (the observed hole values). In addition, the contrast-to-noise ratio (CNR) of the shallowest detectable holes and the deepest undetectable holes were measured to evaluate the contribution of CNR to detectability. Results: The results of this evaluation method corresponded almost exactly with the evaluations made by observers. The extracted hole values reflected the influence of different tube voltages. All extracted holes had an area with a CNR of ≥1.5. Conclusions: This quantitative method of evaluating CBCT image quality may be more useful and less time-consuming than evaluation by observation. PMID:28045343 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA00739&hterms=Dark+web&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DDark%2Bweb','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA00739&hterms=Dark+web&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DDark%2Bweb">Eclipse Images of Io (3 views)</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1997-01-01 These three images of Io in eclipse (top) show volcanic hot spots and airglow associated with volcanic plumes and Io's atmosphere. They were acquired by NASA's Galileo spacecraft during three separate orbits of Jupiter when the moon was in Jupiter's shadow. Brightnesses are color-coded from red which displays the highest intensity to dark blue which displays zero intensity (no light).Below them are the corresponding views of Io in reflected sunlight, reprojected from a global mosaic of images obtained during Galileo's first and second orbits of Jupiter. These lit views help to identify the locations of the hot spots seen in the eclipse images. The grid marks are at 15 degree intervals of latitude and longitude. North is to the top.In the eclipse images (top) small red ovals and perhaps some small green areas are due to thermal emission from volcanic hot spots with temperatures hotter than about 700 kelvin (about 1000 degrees Fahrenheit). Diffuse greenish areas seen near the limb or edge of the moon are probably the result of auroral and/or airglow emissions of neutral species of oxygen or sulfur in volcanic plumes and in Io's patchy atmosphere.All images were acquired by the solid state imaging (CCD) system on NASA's Galileo spacecraft. The top left image was obtained during the spacecraft's fourth orbit (E4) on December 17, 1996, the top middle image during the sixth orbit (E6) on February 21, 1997, and the top right image during the first orbit (G1) on June 29th, 1996. The relatively long exposures used to obtain these eclipse images lead to some smearing of the picture elements which reduces the actual resolution. Unsmeared they would have resolutions of 17.6, 9.1, and 10.5 kilometers per picture element respectively (left to right).The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSH23B2442P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSH23B2442P">Bayesian Analysis of Hmi Images and Comparison to Tsi Variations and MWO Image Observables</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Parker, D. G.; Ulrich, R. K.; Beck, J.; Tran, T. V. 2015-12-01 We have previously applied the Bayesian automatic classification system AutoClass to solar magnetogram and intensity images from the 150 Foot Solar Tower at Mount Wilson to identify classes of solar surface features associated with variations in total solar irradiance (TSI) and, using those identifications, modeled TSI time series with improved accuracy (r > 0.96). (Ulrich, et al, 2010) AutoClass identifies classes by a two-step process in which it: (1) finds, without human supervision, a set of class definitions based on specified attributes of a sample of the image data pixels, such as magnetic field and intensity in the case of MWO images, and (2) applies the class definitions thus found to new data sets to identify automatically in them the classes found in the sample set. HMI high resolution images capture four observables-magnetic field, continuum intensity, line depth and line width-in contrast to MWO's two observables-magnetic field and intensity. In this study, we apply AutoClass to the HMI observables for images from June, 2010 to December, 2014 to identify solar surface feature classes. We use contemporaneous TSI measurements to determine whether and how variations in the HMI classes are related to TSI variations and compare the characteristic statistics of the HMI classes to those found from MWO images. We also attempt to derive scale factors between the HMI and MWO magnetic and intensity observables.The ability to categorize automatically surface features in the HMI images holds out the promise of consistent, relatively quick and manageable analysis of the large quantity of data available in these images. Given that the classes found in MWO images using AutoClass have been found to improve modeling of TSI, application of AutoClass to the more complex HMI images should enhance understanding of the physical processes at work in solar surface features and their implications for the solar-terrestrial environment.Ulrich, R.K., Parker, D, Bertello, L. and </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988SPIE..914...60L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988SPIE..914...60L">A Computational Observer For Performing Contrast-Detail Analysis Of Ultrasound Images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lopez, H.; Loew, M. H. 1988-06-01 Contrast-Detail (C/D) analysis allows the quantitative determination of an imaging system's ability to display a range of varying-size targets as a function of contrast. Using this technique, a contrast-detail plot is obtained which can, in theory, be used to compare image quality from one imaging system to another. The C/D plot, however, is usually obtained by using data from human observer readings. We have shown earlier(7) that the performance of human observers in the task of threshold detection of simulated lesions embedded in random ultrasound noise is highly inaccurate and non-reproducible for untrained observers. We present an objective, computational method for the determination of the C/D curve for ultrasound images. This method utilizes digital images of the C/D phantom developed at CDRH, and lesion-detection algorithms that simulate the Bayesian approach using the likelihood function for an ideal observer. We present the results of this method, and discuss the relationship to the human observer and to the comparability of image quality between systems. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/1246636','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/1246636">Pinhole imaging in Legg-Perthes disease: further observations.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Danigelis, J A 1976-01-01 Fifty-nine patients with Legg-Perthes disease and 12 others were studied using 99mTc-polyphosphate and the pinhole collimator imaging technique. Radiographs of both hips were correlated with images in each patient. In the Legg-Perthes patients, a radionuclide uptake deficiency of variable size was observed in the proximal femoral epiphysis (EOC), which we believe is related to varying degrees of impaired blood supply. During later disease stages, adjacent zones of increased radionuclide activity of revascularization were observed that would replace the uptake defect eventually. Unless radiographic evidence of new bone formation was observed in the EOC, it was impossible to predict either the presence or extent of revascularization until bone imaging was done. Those patients with revascularization activity in the EOC exhibited a relatively short time interval (average, 3.2 months) before evidence of new bone formation radiographically. Others with increased radionuclide concentration limited to the growth plate and/or metaphysis averaged a much longer 7.8 months. In two patients there was a reversal of the initially increased activity in the growth plate, suggesting another vascular insult. There were no false-negative bone-image findings in the 12 cases that clinically and/or radiologically simulated Legg-Perthes disease. Our image studies correlate well with published histopathologic investigations, indicating to us that assessment of extent of pathologic involvement and of the disease course is facilitated by this technique. Subsequently, this could influence treatment selection and provide a more objective baseline from which to judge treatment results. Continued experience suggests pinhole bone imaging has useful clinical application in Legg-Perthes disease and other childhood hip disorders. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.7504D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.7504D">Coordinated observations of postmidnight irregularities and thermospheric neutral winds and temperatures at low latitudes</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Dao, Tam; Otsuka, Yuichi; Shiokawa, Kazuo; Nishioka, Michi; Yamamoto, Mamoru; Buhari, Suhaila M.; Abdullah, Mardina; Husin, Asnawi 2017-07-01 We investigated a postmidnight field-aligned irregularity (FAI) event observed with the Equatorial Atmosphere Radar at Kototabang (0.2°S, 100.3°E, dip latitude 10.4°S) in Indonesia on the night of 9 July 2010 using a comprehensive data set of both neutral and plasma parameters. We examined the rate of total electron content change index (ROTI) obtained from GPS receivers in Southeast Asia, airglow images detected by an all-sky imager, and thermospheric neutral winds and temperatures obtained by a Fabry-Perot interferometer at Kototabang. Altitudes of the F layer (h'F) observed by ionosondes at Kototabang, Chiang Mai, and Chumphon were also surveyed. We found that the postmidnight FAIs occurred within plasma bubbles and coincided with kilometer-scale plasma density irregularities. We also observed an enhancement of the magnetically equatorward thermospheric neutral wind at the same time as the increase of h'F at low-latitude stations, but h'F at a station near the magnetic equator remained invariant. Simultaneously, a magnetically equatorward gradient of thermospheric temperature was identified at Kototabang. The convergence of equatorward neutral winds from the Northern and Southern Hemispheres could be associated with a midnight temperature maximum occurring around the magnetic equator. Equatorward neutral winds can uplift the F layer at low latitudes and increase the growth rate of Rayleigh-Taylor instabilities, causing more rapid extension of plasma bubbles. The equatorward winds in both hemispheres also intensify the eastward Pedersen current, so a large polarization electric field generated in the plasma bubble might play an important role in the generation of postmidnight FAIs. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10566E..26B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10566E..26B">ALISEO on MIOSat: an imaging interferometer for earth observation</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Barducci, A.; Castagnoli, F.; Castellini, G.; Guzzi, D.; Marcoionni, P.; Pippi, I. 2017-11-01 The Italian Space Agency (ASI) decided to perform an low cost Earth observation mission based on a new mini satellite named MIOsat which will carry various technological payloads. Among them an imaging interferometer designed and now ready to be assembled and tested by our Institute. The instrument, named ALISEO (Aerospace Leap-frog Imaging Stationary interferometer for Earth Observation), operates in the common-path Sagnac configuration, and it does not utilize any moving part to scan the phase delays between the two interfering beams. The sensor acquires target images modulated by a pattern of autocorrelation functions of the energy coming from each scene pixel, and the resulting fringe pattern remains spatially fixed with respect to the instrument's field-of-view. The complete interferogram of each target location is retrieved by introducing a relative source-observer motion, which allows any image pixels to be observed under different viewing-angles and experience discrete path differences. The paper describes the main characteristics of the imaging interferometer as well as the overall optical configuration and the electronics layout. Moreover some theoretical issues concerning sampling theory in "common path" imaging interferometry are investigated. The experimental activity performed in laboratory is presented and its outcomes are analysed. Particularly, a set of measurements has been carried out using both standard (certificate) reflectance tiles and natural samples of different volcanic rocks. An algorithm for raw data pre-processing aimed at retrieving the at-sensor radiance spectrum is introduced and its performance is addressed by taking into account various issues such as dark signal subtraction, spectral instrument response compensation, effects of vignetting, and Fourier backtransform. Finally, examples of retrieved absolute reflectance of several samples are sketched at different wavelengths. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950017430','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950017430">Field observations using an AOTF polarimetric imaging spectrometer</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Cheng, Li-Jen; Hamilton, Mike; Mahoney, Colin; Reyes, George 1993-01-01 This paper reports preliminary results of recent field observations using a prototype acousto-optic tunable filter (AOTF) polarimetric imaging spectrometer. The data illustrate application potentials for geoscience. The operation principle of this instrument is different from that of current airborne multispectral imaging instruments, such as AVIRIS. The AOTF instrument takes two orthogonally polarized images at a desired wavelength at one time, whereas AVIRIS takes a spectrum over a predetermined wavelength range at one pixel at a time and the image is constructed later. AVIRIS does not have any polarization measuring capability. The AOTF instrument could be a complement tool to AVIRIS. Polarization measurement is a desired capability for many applications in remote sensing. It is well know that natural light is often polarized due to various scattering phenomena in the atmosphere. Also, scattered light from canopies is reported to have a polarized component. To characterize objects of interest correctly requires a remote sensing imaging spectrometer capable of measuring object signal and background radiation in both intensity and polarization so that the characteristics of the object can be determined. The AORF instrument has the capability to do so. The AOTF instrument has other unique properties. For example, it can provide spectral images immediately after the observation. The instrument can also allow observations to be tailored in real time to perform the desired experiments and to collect only required data. Consequently, the performance in each mission can be increased with minimal resources. The prototype instrument was completed in the beginning of this year. A number of outdoor field experiments were performed with the objective to evaluate the capability of this new technology for remote sensing applications and to determine issues for further improvements. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5526444','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5526444">NOVEL OBSERVATIONS AND POTENTIAL APPLICATIONS USING DIGITAL INFRARED IRIS IMAGING</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Roberts, Daniel K.; Lukic, Ana; Yang, Yongyi; Moroi, Sayoko E.; Wilensky, Jacob T.; Wernick, Miles N. 2017-01-01 Digital infrared (IR) iris photography using a modified digital camera system was carried out on about 300 subjects seen during routine clinical care and research at one facility. Since this image database offered opportunity to gain new insight into the potential utility of IR iris imaging, it was surveyed for unique image patterns. Then, a selection of photos was compiled that would illustrate the spectrum of this imaging experience. Potentially informative image patterns were observed in subjects with cataracts, diabetic retinopathy, Posner-Schlossman syndrome, iridociliary cysts, long anterior lens zonules, nevi, oculocutaneous albinism, pigment dispersion syndrome, pseudophakia, suspected vascular anomaly, and trauma. Image patterns were often unanticipated regardless of pre-existing information and suggest that IR iris imaging may have numerous potential clinical and research applications, some of which may still not be recognized. These observations suggest further development and study of this technology. PMID:19320317 </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active">12</li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active">13</li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA41B2629C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA41B2629C">Greenland Network (GNET) observations of Polar cap Patches and Arcs</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Cesar, V. E.; Pradipta, R.; Pedersen, T. 2017-12-01 TEC values collected with the Greenland Network (GNET) of GPS/GNSS receivers and 630.0 nm airglow emissions recorded with an all-sky imager located at Qaanaaq in Greenland are used to investigate the relationship between the appearance and evolution of polar cap patches (PCP) and Sun-aligned arcs (S-AA) and the characteristics of the solar wind. Both PCP and S-AA produce TEC enhancements, but the PCP velocity is 10 times larger than the S-AA's drift. In addition, PCP move anti-sunwardly and the S-AA move in the dawn-dusk direction. We use these properties of PCPs and S-AAs and calculate the velocity of the TEC enhancements to identify and discriminate between patches and arcs. The physical location of the boundary of the polar cap is based on DMSP observations of particle precipitation. The IMF and other solar wind parameters are gathered with the ACE satellite that is positioned at the L1 point. Our observations indicate that during December 2009, TEC enhancements occur in the polar cap almost every day, but only when the solar wind velocity exceeds 290 km/s. PCPs appear almost immediately after the Bz turns southward; however, the S-AAs develop a few hours after Bz points northward. These conclusions demonstrate the ability of GNET continuous measurements over Greenland to conduct investigations of the formation and evolution of polar cap patches and arcs. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1013931','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1013931">Dual Hemisphere Investigations of Ionospheric Irregularities that Disrupt Radio Communications and Navigation</a> <a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a> 2016-07-25 ignatures of waves that can be used to study both upward and horizonta l ocean-atmosphere co upling. Our primary observat ional technique is optical-one...the first time. 2. Studies of Earthquab and Tsunami-induced Waves in the Ionosphere. One ofthe more spectac.dar uses of all-sky airglow imaging was...the recent discovery of waves in the ionospheric airglow layer caused by the great earthquake and tsunami of 11 March 2011 (Makela et al. , 2011 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910068677&hterms=australian+copyright&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Daustralian%2Bcopyright','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910068677&hterms=australian+copyright&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Daustralian%2Bcopyright">The dark side of Venus - Near-infrared images and spectra from the Anglo-Australian Observatory</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Crisp, D.; Allen, D. A.; Grinspoon, D. H.; Pollack, J. B. 1991-01-01 Near-IR images and spectra of the night side of Venus taken at the Anglo-Australian Telescope during February 1990 reveal four new thermal emission windows at 1.10, 1.18, 1.27, and 1.31 microns, in addition to the previously discovered windows at 1.74 and 2.3 microns. Images of the Venus night side show similar bright and dark markings in all windows, but their contrast is much lower at short wavelengths. The 1.27-micron window includes a bright, high-altitude O2 airglow feature in addition to a thermal contribution from the deep atmosphere. Simulations of the 1.27- and 2.3-micron spectra indicate water vapor mixing ratios near 40 + or - 20 ppm by volume between the surface and the cloud base. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850028663&hterms=Abreu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAbreu%252C%2Bc.','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850028663&hterms=Abreu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAbreu%252C%2Bc.">Tomographic inversion of satellite photometry</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Solomon, S. C.; Hays, P. B.; Abreu, V. J. 1984-01-01 An inversion algorithm capable of reconstructing the volume emission rate of thermospheric airglow features from satellite photometry has been developed. The accuracy and resolution of this technique are investigated using simulated data, and the inversions of several sets of observations taken by the Visible Airglow Experiment are presented. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040003964&hterms=ghosts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dghosts','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040003964&hterms=ghosts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dghosts">Earth Observing-1 Advanced Land Imager: Imaging Performance On-Orbit</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Hearn, D. R. 2002-01-01 This report analyzes the on-orbit imaging performance of the Advanced Land Imager (ALI) on the Earth Observing-1 satellite. The pre-flight calibrations are first summarized. The methods used to reconstruct and geometrically correct the image data from this push-broom sensor are described. The method used here does not refer to the position and attitude telemetry from the spacecraft. Rather, it is assumed that the image of the scene moves across the focal plane with a constant velocity, which can be ascertained from the image data itself. Next, an assortment of the images so reconstructed is presented. Color images sharpened with the 10-m panchromatic band data are shown, and the algorithm for producing them from the 30-m multispectral data is described. The approach taken for assessing spatial resolution is to compare the sharpness of features in the on-orbit image data with profiles predicted on the basis of the pre-flight calibrations. A large assortment of bridge profiles is analyzed, and very good fits to the predicted shapes are obtained. Lunar calibration scans are analyzed to examine the sharpness of the edge-spread function at the limb of the moon. The darkness of the space beyond the limb is better for this purpose than anything that could be simulated on the ground. From these scans, we find clear evidence of scattering in the optical system, as well as some weak ghost images. Scans of planets and stars are also analyzed. Stars are useful point sources of light at all wavelengths, and delineate the point-spread functions of the system. From a quarter-speed scan over the Pleiades, we find that the ALI can detect 6th magnitude stars. The quality of the reconstructed images verifies the capability of the ALI to produce Landsat-type multi spectral data. The signal-to-noise and panchromatic spatial resolution are considerably superior to those of the existing Landsat sensors. The spatial resolution is confirmed to be as good as it was designed to be. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986sao..reptQ....N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986sao..reptQ....N">High resolution astrophysical observations using speckle imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Noyes, R. W.; Nisenson, P.; Papaliolios, C.; Stachnik, R. V. 1986-04-01 This report describes progress under a contract to develop a complete astronomical speckle image reconstruction facility and to apply that facility to the solution of astronomical problems. During the course of the contract we have developed the procedures, algorithms, theory and hardware required to perform that function and have made and interpreted astronomical observations of substantial significance. A principal result of the program was development of a photon-counting camera of innovative design, the PAPA detector. Development of this device was, in our view, essential to making the speckle process into a useful astronomical tool, since the principal impediment to that circumstance in the past was the necessity for application of photon noise compensation procedures which were difficult if not impossible to calibrate. The photon camera made this procedure unnecessary and permitted precision image recovery. The result of this effort and the associated algorithm development was an active program of astronomical observation which included investigations into young stellar objects, supergiant structure and measurements of the helium abundance of the early universe. We have also continued research on recovery of high angular resolution images of the solar surface working with scientists at the Sacramento Peak Observatory in this area. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940026443','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940026443">Solar measurements from the Airglow-Solar Spectrometer Instrument (ASSI) on the San Marco 5 satellite</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Woods, Thomas N. 1994-01-01 The analysis of the solar spectral irradiance from the Airglow-Solar Spectrometer Instrument (ASSI) on the San Marco 5 satellite is the focus for this research grant. A pre-print copy of the paper describing the calibrations of and results from the San Marco ASSI is attached to this report. The calibration of the ASSI included (1) transfer of photometric calibration from a rocket experiment and the Solar Mesosphere Explorer (SME), (2) use of the on-board radioactive calibration sources, (3) validation of the ASSI sensitivity over its field of view, and (4) determining the degradation of the spectrometers. We have determined that the absolute values for the solar irradiance needs adjustment in the current proxy models of the solar UV irradiance, and the amount of solar variability from the proxy models are in reasonable agreement with the ASSI measurements. This research grant also has supported the development of a new solar EUV irradiance proxy model. We expected that the magnetic flux is responsible for most of the heating, via Alfen waves, in the chromosphere, transition region, and corona. From examining time series of solar irradiance data and magnetic fields at different levels, we did indeed find that the chromospheric emissions correlate best with the large magnetic field levels. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999SPIE.3663....8G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999SPIE.3663....8G">Observer performance assessment of JPEG-compressed high-resolution chest images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Good, Walter F.; Maitz, Glenn S.; King, Jill L.; Gennari, Rose C.; Gur, David 1999-05-01 The JPEG compression algorithm was tested on a set of 529 chest radiographs that had been digitized at a spatial resolution of 100 micrometer and contrast sensitivity of 12 bits. Images were compressed using five fixed 'psychovisual' quantization tables which produced average compression ratios in the range 15:1 to 61:1, and were then printed onto film. Six experienced radiologists read all cases from the laser printed film, in each of the five compressed modes as well as in the non-compressed mode. For comparison purposes, observers also read the same cases with reduced pixel resolutions of 200 micrometer and 400 micrometer. The specific task involved detecting masses, pneumothoraces, interstitial disease, alveolar infiltrates and rib fractures. Over the range of compression ratios tested, for images digitized at 100 micrometer, we were unable to demonstrate any statistically significant decrease (p greater than 0.05) in observer performance as measured by ROC techniques. However, the observers' subjective assessments of image quality did decrease significantly as image resolution was reduced and suggested a decreasing, but nonsignificant, trend as the compression ratio was increased. The seeming discrepancy between our failure to detect a reduction in observer performance, and other published studies, is likely due to: (1) the higher resolution at which we digitized our images; (2) the higher signal-to-noise ratio of our digitized films versus typical CR images; and (3) our particular choice of an optimized quantization scheme. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820028848&hterms=8796&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D8796','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820028848&hterms=8796&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D8796">Visible aurora in Jupiter's atmosphere</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Cook, A. F., II; Jones, A. V.; Shemansky, D. E. 1981-01-01 The darkside limb pictures obtained by the imaging experiment on Voyager 1 have been reexamined. It is concluded that the observed luminosity is very likely due at least in part to Io torus aurora. If the effective wavelength of the emission lies in the 4000- to 5000-A region, the slant intensity is estimated to be about 20 kR. The observed double structure may be due to a number of causes such as horizontal structure in auroral emission, aurora plus twilight or photochemical airglow plus aurora. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-STS102-342-024.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-STS102-342-024.html">Earth observation taken during STS-102</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2001-06-14 STS102-342-024 (8-21 March 2001)--- The largest percentage of astronaut out-the-window photography is scientific in nature. However, occasionally scenes such as this one showing the moon over Earth's airglow are irresistable for crew members with cameras. The 35mm scene was recorded by one of the STS-102 astronauts from the aft flight deck of the Space Shuttle Discovery. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AJ....149...50O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AJ....149...50O">Difference Image Analysis of Defocused Observations With CSTAR</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Oelkers, Ryan J.; Macri, Lucas M.; Wang, Lifan; Ashley, Michael C. B.; Cui, Xiangqun; Feng, Long-Long; Gong, Xuefei; Lawrence, Jon S.; Qiang, Liu; Luong-Van, Daniel; Pennypacker, Carl R.; Yang, Huigen; Yuan, Xiangyan; York, Donald G.; Zhou, Xu; Zhu, Zhenxi 2015-02-01 The Chinese Small Telescope ARray carried out high-cadence time-series observations of 27 square degrees centered on the South Celestial Pole during the Antarctic winter seasons of 2008-2010. Aperture photometry of the 2008 and 2010 i-band images resulted in the discovery of over 200 variable stars. Yearly servicing left the array defocused for the 2009 winter season, during which the system also suffered from intermittent frosting and power failures. Despite these technical issues, nearly 800,000 useful images were obtained using g, r, and clear filters. We developed a combination of difference imaging and aperture photometry to compensate for the highly crowded, blended, and defocused frames. We present details of this approach, which may be useful for the analysis of time-series data from other small-aperture telescopes regardless of their image quality. Using this approach, we were able to recover 68 previously known variables and detected variability in 37 additional objects. We also have determined the observing statistics for Dome A during the 2009 winter season; we find the extinction due to clouds to be less than 0.1 and 0.4 mag for 40% and 63% of the dark time, respectively. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950015355','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950015355">Application of MCM image construction to IRAS comet observations</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Schlapfer, Martin F.; Walker, Russell G. 1994-01-01 There is a wealth of IRAS comet data, obtained in both the survey and pointed observations modes. However, these measurements have remained largely untouched due to difficulties in removing instrumental effects from the data. We have developed a version of the Maximum Correlation Method for Image Construction algorithm (MCM) which operates in the moving coordinate system of the comet and properly treats both real cometary motion and apparent motion due to spacecraft parallax. This algorithm has been implemented on a 486/33 PC in FORTRAN and IDL codes. Preprocessing of the IRAS CRDD includes baseline removal, deglitching, and removal of long tails due to dielectric time constants of the detectors. The resulting images are virtually free from instrumental effects and have the highest possible spatial resolution consistent with the data sampling. We present examples of high resolution IRAS images constructed from survey observations of Comets P/Tempel 1 and P/Tempel 2, and pointed observations of IRAS-Araki-Alcock. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss029e005352.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss029e005352.html">Earth Observation taken by the Expedition 29 crew</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-09-16 ISS029-E-005352 (16 Sept. 2011) --? One of the Expedition 29 crew members aboard the International Space Station, flying at an altitude of approximately 220 miles, took this night time picture showing Africa's Congo coast, clouds, airglow and Earth's terminator. Nadir coordinates are 5.32 degrees south latitude and 12.86 degrees east longitude. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SoPh..292..106M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SoPh..292..106M">First Observations from the Multi-Application Solar Telescope (MAST) Narrow-Band Imager</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mathew, Shibu K.; Bayanna, Ankala Raja; Tiwary, Alok Ranjan; Bireddy, Ramya; Venkatakrishnan, Parameswaran 2017-08-01 The Multi-Application Solar Telescope is a 50 cm off-axis Gregorian telescope recently installed at the Udaipur Solar Observatory, India. In order to obtain near-simultaneous observations at photospheric and chromospheric heights, an imager optimized for two or more wavelengths is being integrated with the telescope. Two voltage-tuneable lithium-niobate Fabry-Perot etalons along with a set of interference blocking filters have been used for developing the imager. Both of the etalons are used in tandem for photospheric observations in Fe i 6173 Å and chromospheric observation in Hα 6563 Å spectral lines, whereas only one of the etalons is used for the chromospheric Ca II line at 8542 Å. The imager is also being used for spectropolarimetric observations. We discuss the characterization of the etalons at the above wavelengths, detail the integration of the imager with the telescope, and present a few sets of observations taken with the imager set-up. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17808181','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17808181">Granular convection observed by magnetic resonance imaging.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Ehrichs, E E; Jaeger, H M; Karczmar, G S; Knight, J B; Kuperman, V Y; Nagel, S R 1995-03-17 Vibrations in a granular material can spontaneously produce convection rolls reminiscent of those seen in fluids. Magnetic resonance imaging provides a sensitive and noninvasive probe for the detection of these convection currents, which have otherwise been difficult to observe. A magnetic resonance imaging study of convection in a column of poppy seeds yielded data about the detailed shape of the convection rolls and the depth dependence of the convection velocity. The velocity was found to decrease exponentially with depth; a simple model for this behavior is presented here. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PhDT.........9H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PhDT.........9H">High-latitude electron density observations from the IMAGE radio plasma imager</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Henize, Vance Karl 2003-11-01 Before the IMAGE mission, electron densities in the high latitude, high altitude region of the magnetosphere were measured exclusively by in situ means. The Radio Plasma Imager instrument onboard IMAGE is capable of remotely observing electron densities between 0.01 and 100,000 e-/cm-3 from distances of several Earth radii or more. This allows a global view of the high latitude region that has a far greater accuracy than was previously possible. Soundings of the terrestrial magnetic cusp provide the first remote observations of the dynamics and poleward density profile of this feature continuously over a 60- minute interval. During steady quiet-time solar wind and interplanetary magnetic field conditions, the cusp is shown to be stable in both position and density structure with only slight variations in both. Peak electron densities within the cusp during this time are found to be somewhat higher than predicted. New procedures for deriving electron densities from radio sounding measurements are developed. The addition of curve fitting algorithms significantly increases the amount of useable data. Incorporating forward modeling techniques greatly reduces the computational time over traditional inversion methods. These methods are described in detail. A large number high latitude observations of ducted right-hand extraordinary mode waves made over the course of one year of the IMAGE mission are used to create a three dimensional model of the electron density profile of the terrestrial polar cap region. The dependence of electron density in the polar cap on average geocentric distance (d) is found to vary as d-6.6. This is a significantly steeper gradient than cited in earlier works such as Persoon et al., although the introduction of an asymptotic term provides for basic agreement in the limited region of their joint validity. Latitudinal and longitudinal variations are found to be insignificant. Both the mean profile power law index of the electron density profile </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.8128K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.8128K">Mesospheric Temperatures and Winds measured by a VHF Meteor Radar at King Sejong Station (62.2S, 58.8W), Antarctica</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kim, Yongha; Kim, Jeong-Han; Jee, Geonwha; Lee, Chang-Sup 2010-05-01 A VHF radar at King Sejong Station, Antarctica has been measuring meteor echoes since March 2007. Temperatures near the mesopause are derived from meteor decay times with an improved method of selecting meteor echo samples, and compared with airglow temperatures simultaneously observed by a spectral airglow temperature imager (SATI). The temperatures derived from meteor decay times are mostly consistent with the rotational temperatures of SATI OH(6-2) and O2(0-1) emissions from March through October. During southern summer when SATI cannot be operated due to brief night time, the meteor radar observation shows cold mesospheric temperatures, significantly lower than the CIRA86 model. The meteor radar observation also provides wind field information between 80 and 100 km of altitude. The measured meridional winds seem to follow the summer pole to winter pole circulation, and thus are correlated with the measured seasonal temperature change. However, the correlation between meridional winds and temperatures is not found in day by day base, as a previous study reported. Tidal characteristics of both zonal and meridional winds will also be compared with those of other Antarctic stations. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991SPIE.1444..256C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991SPIE.1444..256C">Observer detection of image degradation caused by irreversible data compression processes</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Chen, Ji; Flynn, Michael J.; Gross, Barry; Spizarny, David 1991-05-01 Irreversible data compression methods have been proposed to reduce the data storage and communication requirements of digital imaging systems. In general, the error produced by compression increases as an algorithm''s compression ratio is increased. We have studied the relationship between compression ratios and the detection of induced error using radiologic observers. The nature of the errors was characterized by calculating the power spectrum of the difference image. In contrast with studies designed to test whether detected errors alter diagnostic decisions, this study was designed to test whether observers could detect the induced error. A paired-film observer study was designed to test whether induced errors were detected. The study was conducted with chest radiographs selected and ranked for subtle evidence of interstitial disease, pulmonary nodules, or pneumothoraces. Images were digitized at 86 microns (4K X 5K) and 2K X 2K regions were extracted. A full-frame discrete cosine transform method was used to compress images at ratios varying between 6:1 and 60:1. The decompressed images were reprinted next to the original images in a randomized order with a laser film printer. The use of a film digitizer and a film printer which can reproduce all of the contrast and detail in the original radiograph makes the results of this study insensitive to instrument performance and primarily dependent on radiographic image quality. The results of this study define conditions for which errors associated with irreversible compression cannot be detected by radiologic observers. The results indicate that an observer can detect the errors introduced by this compression algorithm for compression ratios of 10:1 (1.2 bits/pixel) or higher. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910040919&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910040919&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight">A method for the retrieval of atomic oxygen density and temperature profiles from ground-based measurements of the O(+)(2D-2P) 7320 A twilight airglow</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Fennelly, J. A.; Torr, D. G.; Richards, P. G.; Torr, M. R.; Sharp, W. E. 1991-01-01 This paper describes a technique for extracting thermospheric profiles of the atomic-oxygen density and temperature, using ground-based measurements of the O(+)(2D-2P) doublet at 7320 and 7330 A in the twilight airglow. In this method, a local photochemical model is used to calculate the 7320-A intensity; the method also utilizes an iterative inversion procedure based on the Levenberg-Marquardt method described by Press et al. (1986). The results demonstrate that, if the measurements are only limited by errors due to Poisson noise, the altitude profiles of neutral temperature and atomic oxygen concentration can be determined accurately using currently available spectrometers. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.3410H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.3410H">Edge of polar cap patches</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hosokawa, K.; Taguchi, S.; Ogawa, Y. 2016-04-01 On the night of 4 December 2013, a sequence of polar cap patches was captured by an all-sky airglow imager (ASI) in Longyearbyen, Norway (78.1°N, 15.5°E). The 630.0 nm airglow images from the ASI of 4 second exposure time, oversampled the emission of natural lifetime (with quenching) of at least ˜30 sec, introduce no observational blurring effects. By using such high-quality ASI images, we succeeded in visualizing an asymmetry in the gradients between the leading/trailing edges of the patches in a 2-D fashion. The gradient in the leading edge was found to be 2-3 times steeper than that in the trailing edge. We also identified fingerlike structures, appearing only along the trailing edge of the patches, whose horizontal scale size ranged from 55 to 210 km. These fingers are considered to be manifestations of plasma structuring through the gradient-drift instability (GDI), which is known to occur only along the trailing edge of patches. That is, the current 2-D observations visualized, for the first time, how GDI stirs the patch plasma and such a mixing process makes the trailing edge more gradual. This result strongly implies a close connection between the GDI-driven plasma stirring and the asymmetry in the large-scale shape of patches and then suggests that the fingerlike structures can be used as markers to estimate the fine-scale structure in the plasma flow within patches. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active">13</li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active">14</li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000091592','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000091592">High-Definition Television (HDTV) Images for Earth Observations and Earth Science Applications</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Robinson, Julie A.; Holland, S. Douglas; Runco, Susan K.; Pitts, David E.; Whitehead, Victor S.; Andrefouet, Serge M. 2000-01-01 As part of Detailed Test Objective 700-17A, astronauts acquired Earth observation images from orbit using a high-definition television (HDTV) camcorder, Here we provide a summary of qualitative findings following completion of tests during missions STS (Space Transport System)-93 and STS-99. We compared HDTV imagery stills to images taken using payload bay video cameras, Hasselblad film camera, and electronic still camera. We also evaluated the potential for motion video observations of changes in sunlight and the use of multi-aspect viewing to image aerosols. Spatial resolution and color quality are far superior in HDTV images compared to National Television Systems Committee (NTSC) video images. Thus, HDTV provides the first viable option for video-based remote sensing observations of Earth from orbit. Although under ideal conditions, HDTV images have less spatial resolution than medium-format film cameras, such as the Hasselblad, under some conditions on orbit, the HDTV image acquired compared favorably with the Hasselblad. Of particular note was the quality of color reproduction in the HDTV images HDTV and electronic still camera (ESC) were not compared with matched fields of view, and so spatial resolution could not be compared for the two image types. However, the color reproduction of the HDTV stills was truer than colors in the ESC images. As HDTV becomes the operational video standard for Space Shuttle and Space Station, HDTV has great potential as a source of Earth-observation data. Planning for the conversion from NTSC to HDTV video standards should include planning for Earth data archiving and distribution. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720027233&hterms=May+13th+1969&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMay%2B13th%2B1969','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720027233&hterms=May+13th+1969&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMay%2B13th%2B1969">Simultaneous measurements of the hydrogen airglow emissions of Lyman alpha, Lyman beta, and Balmer alpha.</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Weller, C. S.; Meier, R. R.; Tinsley, B. A. 1971-01-01 Comparison of Lyman-alpha, 740- to 1050-A, and Balmer-alpha airglow measurements made at 134 deg solar-zenith angle on Oct. 13, 1969, with resonance-scattering models of solar radiation. Model comparison with Lyman-alpha data fixes the hydrogen column abundance over 215 km to 2 x 10 to the 13th per cu cm within a factor of 2. Differences between the Lyman-alpha model and data indicate a polar-equatorial departure from spherical symmetry in the hydrogen distribution. A Lyman-beta model based on the hydrogen distribution found to fit the Lyman-alpha data fits the spatial variation of the 740- to 1050-A data well from 100 to 130 km, but it does not fit the data well at higher altitudes; thus the presence of more rapidly absorbed shorter-wavelength radiation is indicated. This same resonance-scattering model yields Balmer-alpha intensities that result in good spatial agreement with the Balmer-alpha measurements, but a fivefold increase in the measured solar line center Lyman-beta flux is required (as required for the Lyman-beta measurement). The intensity ratio of Lyman-beta and Balmer-alpha at night is found to be a simple measure of the hydrogen optical depth if measurements with good accuracy can be made in the visible and ultraviolet spectrum. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003DPS....35.1107T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003DPS....35.1107T">Cassini imaging observations of Jupiter's rings</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Throop, H. B.; Porco, C. C.; West, R. A.; Burns, J. A.; Showalter, M. R.; Nicholson, P. D. 2003-05-01 Cassini's Imaging Science Subsystem (ISS) instrument took nearly 1200 images of the Jupiter ring system during the spacecraft's 6-month encounter with Jupiter. These observations constitute the most complete dataset of the ring taken by a single instrument, both in phase angle (0.5 - 120° at seven angles) and wavelength (0.45 - 0.93 μ {m} through eight filters). The main ring was detected in all targeted exposures; the halo and gossamer rings were too faint to be observed above the planet's stray light. The optical depth and radial profile of the main ring are unchanged from that of previous studies. No evidence for broad asymmetries within the ring were found; we did identify possible evidence for 1000 km-scale clumps within the ring. Cassini observations at a phase angle of 64° place an upper limit on the ring's full thickness of 80 km. We have combined the Cassini ISS and VIMS observations with those from Voyager, HST, Keck, Galileo, Palomar, and IRTF. We have fit the entire suite of data using a photometric model that includes microscopic silicate dust grains as well as larger, long-lived `parent bodies' that engender this dust. Our dust grain model considers a range of spheroidal particle shapes computed using the T-matrix method (Mishchenko & Travis 1998). Our best-fit model to all the data indicates an optical depth of small particles of τ s = 4.7x 10-6 and large bodies τ l = 1.3x 10-6. The dust is concentrated about a radius of 15 μ {m}. The data are fit significantly better using non-spherical rather than spherical dust grains. The parent bodies themselves must be very red from 0.4--2.5 μ {m} and may have absorption features near 0.9 μ {m} and 2.2 μ {m}. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880066225&hterms=Abreu&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DAbreu%252C%2Bc.','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880066225&hterms=Abreu&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DAbreu%252C%2Bc.">The auroral 6300 A emission - Observations and modeling</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Solomon, Stanley C.; Hays, Paul B.; Abreu, Vincent J. 1988-01-01 A tomographic inversion is used to analyze measurements of the auroral atomic oxygen emission line at 6300 A made by the atmosphere explorer visible airglow experiment. A comparison is made between emission altitude profiles and the results from an electron transport and chemical reaction model. Measurements of the energetic electron flux, neutral composition, ion composition, and electron density are incorporated in the model. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AnGeo..35..567R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AnGeo..35..567R">Seasonal MLT-region nightglow intensities, temperatures, and emission heights at a Southern Hemisphere midlatitude site</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Reid, Iain M.; Spargo, Andrew J.; Woithe, Jonathan M.; Klekociuk, Andrew R.; Younger, Joel P.; Sivjee, Gulamabas G. 2017-04-01 We consider 5 years of spectrometer measurements of OH(6-2) and O2(0-1) airglow emission intensities and temperatures made near Adelaide, Australia (35° S, 138° E), between September 2001 and August 2006 and compare them with measurements of the same parameters from at the same site using an airglow imager, with the intensities of the OH(8-3) and O(1S) emissions made with a filter photometer, and with 2 years of Aura MLS (Microwave Limb Sounder) v3.3 temperatures and 4.5 years of TIMED SABER (Thermosphere Ionosphere Mesosphere Energetics and Dynamics Sounding of the Atmosphere using Broadband Emission Radiometry) v2.0 temperatures for the same site. We also consider whether we can recover the actual emission heights from the intercomparison of the ground-based and satellite observations. We find a significant improvement in the correlation between the spectrometer OH and SABER temperatures by interpolating the latter to constant density surfaces determined using a meteor radar. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3196628','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3196628">New Developments in Observer Performance Methodology in Medical Imaging</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Chakraborty, Dev P. 2011-01-01 A common task in medical imaging is assessing whether a new imaging system, or a variant of an existing one, is an improvement over an existing imaging technology. Imaging systems are generally quite complex, consisting of several components – e.g., image acquisition hardware, image processing and display hardware and software, and image interpretation by radiologists– each of which can affect performance. While it may appear odd to include the radiologist as a “component” of the imaging chain, since the radiologist’s decision determines subsequent patient care, the effect of the human interpretation has to be included. Physical measurements like modulation transfer function, signal to noise ratio, etc., are useful for characterizing the non-human parts of the imaging chain under idealized and often unrealistic conditions, such as uniform background phantoms, target objects with sharp edges, etc. Measuring the effect on performance of the entire imaging chain, including the radiologist, and using real clinical images, requires different methods that fall under the rubric of observer performance methods or “ROC analysis”. The purpose of this paper is to review recent developments in this field, particularly with respect to the free-response method. PMID:21978444 </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006OptRv..13..215M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006OptRv..13..215M">Imaging Analysis of Near-Field Recording Technique for Observation of Biological Specimens</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Moriguchi, Chihiro; Ohta, Akihiro; Egami, Chikara; Kawata, Yoshimasa; Terakawa, Susumu; Tsuchimori, Masaaki; Watanabe, Osamu 2006-07-01 We present an analysis of the properties of an imaging based on a near-field recording technique in comparison with simulation results. In the system, the optical field distributions localized near the specimens are recorded as the surface topographic distributions of a photosensitive film. It is possible to observe both soft and moving specimens, because the system does not require a scanning probe to obtain the observed image. The imaging properties are evaluated using fine structures of paramecium, and we demonstrate that it is possible to observe minute differences of refractive indices. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770028738&hterms=limnology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlimnology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770028738&hterms=limnology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlimnology">Imaging radar observations of frozen Arctic lakes</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Elachi, C.; Bryan, M. L.; Weeks, W. F. 1976-01-01 A synthetic aperture imaging L-band radar flown aboard the NASA CV-990 remotely sensed a number of ice-covered lakes about 48 km northwest of Bethel, Alaska. The image obtained is a high resolution, two-dimensional representation of the surface backscatter cross section, and large differences in backscatter returns are observed: homogeneous low returns, homogeneous high returns and/or low returns near lake borders, and high returns from central areas. It is suggested that a low return indicates that the lake is frozen completely to the bottom, while a high return indicates the presence of fresh water between the ice cover and the lake bed. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997AAS...191.1102R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997AAS...191.1102R">First Space VLBI Observations and Images Using the VLBA and VSOP</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Romney, J. D.; Benson, J. M.; Claussen, M. J.; Desai, K. M.; Flatters, C.; Mioduszewski, A. J.; Ulvestad, J. S. 1997-12-01 The National Radio Astronomy Observatory (NRAO) is a participant in the VSOP Space VLBI mission, an international collaboration led by Japan's Institute of Space and Astronautical Science. NRAO has committed up to 30% of scheduled observing time on the Very Long Baseline Array (VLBA), and corresponding correlation resources, to Space VLBI observations. The NRAO Space VLBI Project, funded by NASA, has been working for several years to complete the necessary enhancements to the VLBA correlator and the AIPS image processing system. These developments were completed by the time of the successful launch of the VSOP mission's Halca spacecraft on 1997 February 12. As part of the in-orbit checkout phase, the first Space VLBI fringes from a VLBA observation were detected on 1997 June 12, and the VSOP mission's first images, in both the 1.6- and 5-GHz bands, were obtained shortly thereafter. In-orbit test observations continued through early September, with the first General Observing Time (GOT) scientific observations beginning in July. Through mid-October, a total of 20 Space VLBI observations, comprising 190 hours, had been completed at the VLBA correlator. This paper reviews the unique features of correlation and imaging of Space VLBI observations. These include, for correlation, the ephemeris for an orbiting VLBI ``station'' which is not fixed on the surface of the earth, and the requirement to close the loop on the phase-transfer process from a frequency standard on the ground to the spacecraft. Images from a number of early tests and scientific observations are presented. NRAO's user-support program, providing expert assistance in data analysis to Space VLBI observers, is also described. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGP51A3713A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGP51A3713A">Small-scale field-aligned currents caused by tropical cyclones as observed by the SWARM satellites above the ionosphere</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Aoyama, T.; Iyemori, T.; Nakanishi, K. 2014-12-01 We present case studies of small-scale magnetic fluctuations above typhoons, hurricanes and cyclones as observed by the swarm constellation. It is reported lately that AGWs(atmospheric gravity waves) generated by meteorological phenomena in the troposphere such as typhoons and tornadoes, large earthquakes and volcanic eruptions propagate to the mesosphere and thermosphere. We observe them in various forms(e.g. airglows, ionospheric disturbances and TEC variations). We are proposing the following model. AGWs caused by atmospheric disturbances in the troposphere propagate to the ionospheric E-layer, drive dynamo action and generate field-aligned currents. The satellites observe magnetic fluctuations above the ionosphere. In this presentation, we focus on cases of tropical cyclone(hurricanes in North America, typhoons in North-West Pacific). </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJWC.11922002S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJWC.11922002S">Development of Fluorescence Imaging Lidar for Boat-Based Coral Observation</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sasano, Masahiko; Imasato, Motonobu; Yamano, Hiroya; Oguma, Hiroyuki 2016-06-01 A fluorescence imaging lidar system installed in a boat-towable buoy has been developed for the observation of reef-building corals. Long-range fluorescent images of the sea bed can be recorded in the daytime with this system. The viability of corals is clear in these fluorescent images because of the innate fluorescent proteins. In this study, the specifications and performance of the system are shown. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA34A..07K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA34A..07K">Effect of equatorial electrodynamics on low-latitude thermosphere as inferred from neutral optical dayglow emission observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Karan, D. K.; Duggirala, P. R. 2017-12-01 The diurnal variations in daytime airglow emission intensity measurements at three wavelengths OI 777.4 nm, OI 630.0 nm, and OI 557.7 nm made from a low-latitude location, Hyderabad (Geographic 17.50 N, 78.40 E; 8.90 N Mag. Lat) in India have been investigated. The intensity patterns showed both symmetric and asymmetric behavior in their respective diurnal emission variability with respect to local noon. The asymmetric diurnal behavior is not expected considering the photochemical nature of the production mechanisms. The reason for this observed asymmetric diurnal behavior has been found to be predominantly the temporal variation in the equatorial electrodynamics. The plasma that is transported across latitudes due to the action of varying electric field strength over the magnetic equator in the daytime contributes to the asymmetric diurnal behavior in the neutral daytime airglow emissions. Independent magnetic and radio measurements support this finding. It is also noted that this asymmetric diurnal behavior in the neutral emission intensities has a solar cycle dependence with more number of days during high solar activity period showing asymmetric diurnal behavior compared to those during low-solar activity epoch. These intensity variations over long time scale demonstrate that the daytime neutral optical emissions are extremely sensitive to the changes in the eastward electric field over low- and equatorial-latitudes. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PASP..129e5002W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PASP..129e5002W">Ground-based Observation System Development for the Moon Hyper-spectral Imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Wang, Yang; Huang, Yu; Wang, Shurong; Li, Zhanfeng; Zhang, Zihui; Hu, Xiuqing; Zhang, Peng 2017-05-01 The Moon provides a suitable radiance source for on-orbit calibration of space-borne optical instruments. A ground-based observation system dedicated to the hyper-spectral radiometry of the Moon has been developed for improving and validating the current lunar model. The observation instrument using a dispersive imaging spectrometer is particularly designed for high-accuracy observations of the lunar radiance. The simulation and analysis of the push-broom mechanism is made in detail for lunar observations, and the automated tracking and scanning is well accomplished in different observational condition. A three-month series of hyper-spectral imaging experiments of the Moon have been performed in the wavelength range from 400 to 1000 nm near Lijiang Observatory (Yunnan, China) at phase angles -83°-87°. Preliminary results and data comparison are presented, and it shows the instrument performance and lunar observation capability of this system are well validated. Beyond previous measurements, this observation system provides the entire lunar disk images of continuous spectral coverage by adopting the push-broom mode with special scanning scheme and leads to the further research of lunar photometric model. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.2569B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.2569B">C/NOFS observations of electromagnetic coupling between magnetically conjugate MSTID structures</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Burke, W. J.; Martinis, C. R.; Lai, P. C.; Gentile, L. C.; Sullivan, C.; Pfaff, R. F. 2016-03-01 This report demonstrates empirically that couplings between magnetically conjugate medium-scale traveling ionospheric disturbances (MSTIDs) are electromagnetic in nature. This is accomplished by comparing plasma density, electric, and magnetic perturbations sampled simultaneously by sensors on the Communication/Navigation Outage Forecasting System (C/NOFS) satellite. During the period of interest on 17 February 2010, C/NOFS made three consecutive orbits while magnetically conjugate to the field of view of an all-sky imager located at El Leoncito, Argentina (31.8°S, 69.3°W). Imaged 630.0 nm airglow was characterized by alternating bands of relatively bright and dark emissions that were aligned from northeast to southwest and propagated toward the northwest, characteristic of MSTIDs in the southern hemisphere. Measurable Poynting fluxes flow along the Earth's magnetic field (S||) from "generator" to "load" hemispheres. While S|| was predominantly away from the ionosphere above El Leoncito, interhemispheric energy flows were not one-way streets. Measured Poynting flux intensities diminished with time over the three C/NOFS passes, suggesting that source mechanisms of MSTIDs were absent or that initial impedance mismatches between the two hemispheres approached an equilibrium status. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20180001887&hterms=electromagnetic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Delectromagnetic','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20180001887&hterms=electromagnetic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Delectromagnetic">C/NOFS Observations of Electromagnetic Coupling Between Magnetically Conjugate MSTID Structures</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Burke, W. J.; Martinis, C. R.; Lai, P. C.; Gentile, L. C.; Sullivan, C.; Pfaff, Robert F. 2016-01-01 This report demonstrates empirically that couplings between magnetically conjugate medium-scale traveling ionospheric disturbances (MSTIDs) are electromagnetic in nature. This is accomplished by comparing plasma density, electric, and magnetic perturbations sampled simultaneously by sensors on the Communication Navigation Outage Forecasting System (CNOFS) satellite. During the period of interest on 17 February 2010, CNOFS made three consecutive orbits while magnetically conjugate to the field of view of an all-sky imager located at El Leoncito, Argentina (31.8degS, 69.3degW). Imaged 630.0 nm airglow was characterized by alternating bands of relatively bright and dark emissions that were aligned from northeast to southwest and propagated toward the northwest, characteristic of MSTIDs in the southern hemisphere. Measurable Poynting fluxes flow along the Earths magnetic field (S) from generator to load hemispheres. While S was predominantly away from the ionosphere above El Leoncito, interhemispheric energy flows were not one-way streets. Measured Poynting flux intensities diminished with time over the three CNOFS passes, suggesting that source mechanisms of MSTIDs were absent or that initial impedance mismatches between the two hemispheres approached an equilibrium status. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8318E..0TG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8318E..0TG">Performance characteristics of a visual-search human-model observer with sparse PET image data</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gifford, Howard C. 2012-02-01 As predictors of human performance in detection-localization tasks, statistical model observers can have problems with tasks that are primarily limited by target contrast or structural noise. Model observers with a visual-search (VS) framework may provide a more reliable alternative. This framework provides for an initial holistic search that identifies suspicious locations for analysis by a statistical observer. A basic VS observer for emission tomography focuses on hot "blobs" in an image and uses a channelized nonprewhitening (CNPW) observer for analysis. In [1], we investigated this model for a contrast-limited task with SPECT images; herein, a statisticalnoise limited task involving PET images is considered. An LROC study used 2D image slices with liver, lung and soft-tissue tumors. Human and model observers read the images in coronal, sagittal and transverse display formats. The study thus measured the detectability of tumors in a given organ as a function of display format. The model observers were applied under several task variants that tested their response to structural noise both at the organ boundaries alone and over the organs as a whole. As measured by correlation with the human data, the VS observer outperformed the CNPW scanning observer. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.7126E..0MT','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.7126E..0MT">High-speed imaging system for observation of discharge phenomena</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tanabe, R.; Kusano, H.; Ito, Y. 2008-11-01 A thin metal electrode tip instantly changes its shape into a sphere or a needlelike shape in a single electrical discharge of high current. These changes occur within several hundred microseconds. To observe these high-speed phenomena in a single discharge, an imaging system using a high-speed video camera and a high repetition rate pulse laser was constructed. A nanosecond laser, the wavelength of which was 532 nm, was used as the illuminating source of a newly developed high-speed video camera, HPV-1. The time resolution of our system was determined by the laser pulse width and was about 80 nanoseconds. The system can take one hundred pictures at 16- or 64-microsecond intervals in a single discharge event. A band-pass filter at 532 nm was placed in front of the camera to block the emission of the discharge arc at other wavelengths. Therefore, clear images of the electrode were recorded even during the discharge. If the laser was not used, only images of plasma during discharge and thermal radiation from the electrode after discharge were observed. These results demonstrate that the combination of a high repetition rate and a short pulse laser with a high speed video camera provides a unique and powerful method for high speed imaging. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.1391G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.1391G">Nightglow on Venus: Venus Express NO(UV), O2(IR), and OH(IR) Observations and Implications for Upper Atmosphere Dynamics</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gerard, Jean-Claude Ground-based and space observations have shown the presence of several emissions in the Venus nightglow. The gamma and delta bands of nitric oxide between 190 and 270 nm are ubiquitous on the Venus night side. They are excited by radiative recombination of N and O atoms created by photodissociation of CO2 and N2 molecules on the dayside of the planet. This emission has been extensively observed with the SPICAV spectrograph on board Venus Express. It shows a maximum limb brightness near 115 km. Similarly, the O2 (1 ∆) emission at 1.27 µm is excited by three-body recombination of O atoms which produces an airglow layer near 96 km, as was demonstrated by several studies based on observations with the VIRTIS instrument on Venus Express. The two emissions are variable in space and time and show little spatial correlation. The N and O atoms are transported to the night side by the subsolar to antisolar global circulation in the thermosphere generated by the thermal contrast between the two sides of Venus. A zonal circulation is also observed in the mesosphere and a region exists where both transport regimes influence the distribution of O and N atoms and the resulting airglow emissions. The statistical location of the NO and O2 bright spots is not identical, which suggests that the dynamical regime is different at the altitudes of the two layers. Finally, the statistical characteristics of the OH Meinel bands in the near infrared will be presented. This emission shows similarities with O2 (1 ∆), presumably because atomic oxygen is a common precursor to both emissions. The growing information on the brightness, vertical and horizontal distribution of these emissions now provides constraints on the dynamics prevailing in the Venus upper atmosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018uhec.confa1042T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018uhec.confa1042T">NICHE: Non-Imaging Cherenkov Light Observation at the TA Site</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tsunesada, Yoshiki; Omura, Yugo; Shin, BokKyun; Bergman, Douglas R.; Krizmanic, John F.; Nonaka, Toshiyuki The Non-Imaging CHErenkov Array (NICHE) is a low energy extension to the Telescope Array and TALE using an array of closely spaced (70-100 m) light collectors covering an area of up to a square km. The target is cosmic rays with energies above the knee, including the "transition region" above which Galactic cosmic rays are no more confined by the galactic magnetic field. It will be deployed in the field of view of TALE and will overlap it in energy range. TALE can observe events in the energy range 3-30 PeV by non-imaging air-Cherenkov, so NICHE and TALE will observe imaging/non-imaging Cherenkov hybrid events. NICHE itself will use both the Cherenkov lateral distribution and the Cherenkov time-width lateral distribution in measuring air showers. These two methods will allow shower energy and Xmax to be determined to infer primary types of cosmic nuclei. A prototype of the array with 15 counters, called j-NICHE, is currently being built. We describe the design of the experiment and the status of the detector development. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19304608','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19304608">The effect of the observer vantage point on perceived distortions in linear perspective images.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Todorović, Dejan 2009-01-01 Some features of linear perspective images may look distorted. Such distortions appear in two drawings by Jan Vredeman de Vries involving perceived elliptical, instead of circular, pillars and tilted, instead of upright, columns. Distortions may be due to factors intrinsic to the images, such as violations of the so-called Perkins's laws, or factors extrinsic to them, such as observing the images from positions different from their center of projection. When the correct projection centers for the two drawings were reconstructed, it was found that they were very close to the images and, therefore, practically unattainable in normal observation. In two experiments, enlarged versions of images were used as stimuli, making the positions of the projection centers attainable for observers. When observed from the correct positions, the perceived distortions disappeared or were greatly diminished. Distortions perceived from other positions were smaller than would be predicted by geometrical analyses, possibly due to flatness cues in the images. The results are relevant for the practical purposes of creating faithful impressions of 3-D spaces using 2-D images. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active">14</li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active">15</li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050215631&hterms=Cluster+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCluster%2Banalysis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050215631&hterms=Cluster+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCluster%2Banalysis">Analysis of plasmaspheric plumes: CLUSTER and IMAGE observations and numerical simulations</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Darouzet, Fabien; DeKeyser, Johan; Decreau, Pierrette; Gallagher, Dennis; Pierrard, Viviane; Lemaire, Joseph; Dandouras, Iannis; Matsui, Hiroshi; Dunlop, Malcolm; Andre, Mats 2005-01-01 Plasmaspheric plumes have been routinely observed by CLUSTER and IMAGE. The CLUSTER mission provides high time resolution four-point measurements of the plasmasphere near perigee. Total electron density profiles can be derived from the plasma frequency and/or from the spacecraft potential (note that the electron spectrometer is usually not operating inside the plasmasphere); ion velocity is also measured onboard these satellites (but ion density is not reliable because of instrumental limitations). The EUV imager onboard the IMAGE spacecraft provides global images of the plasmasphere with a spatial resolution of 0.1 RE every 10 minutes; such images acquired near apogee from high above the pole show the geometry of plasmaspheric plumes, their evolution and motion. We present coordinated observations for 3 plume events and compare CLUSTER in-situ data (panel A) with global images of the plasmasphere obtained from IMAGE (panel B), and with numerical simulations for the formation of plumes based on a model that includes the interchange instability mechanism (panel C). In particular, we study the geometry and the orientation of plasmaspheric plumes by using a four-point analysis method, the spatial gradient. We also compare several aspects of their motion as determined by different methods: (i) inner and outer plume boundary velocity calculated from time delays of this boundary observed by the wave experiment WHISPER on the four spacecraft, (ii) ion velocity derived from the ion spectrometer CIS onboard CLUSTER, (iii) drift velocity measured by the electron drift instrument ED1 onboard CLUSTER and (iv) global velocity determined from successive EUV images. These different techniques consistently indicate that plasmaspheric plumes rotate around the Earth, with their foot fully co-rotating, but with their tip rotating slower and moving farther out. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10136E..0PL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10136E..0PL">Foveated model observers to predict human performance in 3D images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lago, Miguel A.; Abbey, Craig K.; Eckstein, Miguel P. 2017-03-01 We evaluate 3D search requires model observers that take into account the peripheral human visual processing (foveated models) to predict human observer performance. We show that two different 3D tasks, free search and location-known detection, influence the relative human visual detectability of two signals of different sizes in synthetic backgrounds mimicking the noise found in 3D digital breast tomosynthesis. One of the signals resembled a microcalcification (a small and bright sphere), while the other one was designed to look like a mass (a larger Gaussian blob). We evaluated current standard models observers (Hotelling; Channelized Hotelling; non-prewhitening matched filter with eye filter, NPWE; and non-prewhitening matched filter model, NPW) and showed that they incorrectly predict the relative detectability of the two signals in 3D search. We propose a new model observer (3D Foveated Channelized Hotelling Observer) that incorporates the properties of the visual system over a large visual field (fovea and periphery). We show that the foveated model observer can accurately predict the rank order of detectability of the signals in 3D images for each task. Together, these results motivate the use of a new generation of foveated model observers for predicting image quality for search tasks in 3D imaging modalities such as digital breast tomosynthesis or computed tomography. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820038646&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820038646&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight">Exospheric temperatures deduced from 7320- to 7330-A /O/+//2P/ - O/+//2D// twilight observations</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Yee, J. H.; Abreu, V. J. 1982-01-01 A technique developed to deduce exospheric temperatures from the 7320- to 7330-A emission measured by the visible airglow experiment on board the AE-E satellite is considered. An excess emission in the measured 7320- to 7330-A brightness is noticed as a result of the interaction between the spacecraft and the atmosphere. The observed brightnesses are corrected for this effect. The galactic background emission is also carefully subtracted. The deduced temperatures exhibit a positive correlation with solar activity. It varies from approximately 700 K in late 1976 to approximately 1700 K at the peak of this solar cycle. The presence of a nonthermal oxygen corona is considered inconclusive. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.7055E..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.7055E..07L">Dualband infrared imaging spectrometer: observations of the moon</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> LeVan, Paul D.; Beecken, Brian P.; Lindh, Cory 2008-08-01 We reported previously on full-disk observations of the sun through a layer of black polymer, used to protect the entrance aperture of a novel dualband spectrometer while transmitting discrete wavelength regions in the MWIR & LWIR1. More recently, the spectrometer was used to assess the accuracy of recovery of unknown blackbody temperatures2. Here, we briefly describe MWIR observations of the full Moon made in Jan 2008. As was the case for the solar observations, the Moon was allowed to drift across the spectrometer slit by Earth's rotation. A detailed sensor calibration performed prior to the observations accounts for sensor non-uniformities; the spectral images of the Moon therefore include atmospheric transmission features. Our plans are to repeat the observations at liquid helium temperatures, thereby allowing both MWIR & LWIR spectral coverage. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME53A..01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME53A..01P">Applications of Geostationary Ocean Color Imager (GOCI) observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Park, Y. J. 2016-02-01 Ocean color remote-sensing technique opened a new era for biological oceanography by providing the global distribution of phytoplankton biomass every a few days. It has been proved useful for a variety of applications in coastal waters as well as oceanic waters. However, most ocean color sensors deliver less than one image per day for low and middle latitude areas, and this once a day image is insufficient to resolve transient or high frequency processes. Korean Geostationary Ocean Color Imager (GOCI), the first ever ocean color instrument operated on geostationary orbit, is collecting ocean color radiometry (OCR) data (multi-band radiances at the visible to NIR spectral wavelengths) since July, 2010. GOCI has an unprecedented capability to provide eight OCR images a day with a 500m resolution for the North East Asian seas Monitoring the spatial and temporal variability is important to understand many processes occurring in open ocean and coastal environments. With a series of images consecutively acquired by GOCI, we are now able to look into (sub-)diurnal variabilities of coastal ocean color products such as phytoplankton biomass, suspended particles concentrations, and primary production. The eight images taken a day provide another way to derive maps of ocean current velocity. Compared to polar orbiters, GOCI delivers more frequent images with constant viewing angle, which enables to better monitor and thus respond to coastal water issues such as harmful algal blooms, floating green and brown algae. The frequent observation capability for local area allows us to respond timely to natural disasters and hazards. GOCI images are often useful to identify sea fog, sea ice, wild fires, volcanic eruptions, transport of dust aerosols, snow covered area, etc. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss029e034092.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss029e034092.html">Progress 42 re-entry</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-10-29 ISS029-E-034092 (29 Oct. 2011) --- This unusual photograph, captured by one of the Expedition 29 crew members aboard the International Space Station, highlights the reentry plasma trail (center) of Progress 42P (M-10M) supply vehicle. Progress 42P docked at the space station on April 29, 2011, and was undocked and de-orbited approximately 183 days later on Oct. 29, 2011. The ISS was located over the southern Pacific Ocean when this image was taken. Light from the rising sun illuminates the curvature of the Earth limb (horizon line) at top, but does not completely overwhelm the airglow visible at image top left. Airglow is caused by light emitted at specific wavelengths by atoms and molecules excited by ultraviolet radiation in the upper atmosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JASTP.140....1J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JASTP.140....1J">A case study of A mesoscale gravity wave in the MLT region using simultaneous multi-instruments in Beijing</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Jia, Mingjiao; Xue, Xianghui; Dou, Xiankang; Tang, Yihuan; Yu, Chao; Wu, Jianfei; Xu, Jiyao; Yang, Guotao; Ning, Baiqi; Hoffmann, Lars 2016-03-01 In this work, we used observational data from an all-sky airglow imager at Xinglong (40.2 °N, 117.4 °E), a sodium lidar at Yanqing (40.4 °N, 116.0 °E) and a meteor radar at Shisanling (40.3 °N, 116.2 °E) to study the propagation of a mesoscale gravity wave. During the night of March 1, 2011, the imager identified a mesoscale gravity wave structure in the OH airglow that had a wave period of 2 hours, propagated along an azimuthal direction (clockwise) with an angle of 163°, a phase speed of 73 m/s, and a horizontal wavelength of 566 km. Simultaneous measurements provided by the sodium lidar also showed a perturbation in the sodium layer with a 2-hour period. Based on the SABER/TIMED and radar data, we estimated that the momentum flux and the energy flux of the gravity wave were approximately 0.59 m2/s2 and 0.22 mW/m2, respectively. Ray-tracing analysis showed that the gravity wave was likely generated in the center of Lake Baikal owing to the existence of a jet- front system in the upper troposphere at that time. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4963469','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4963469">Design of a practical model-observer-based image quality assessment method for x-ray computed tomography imaging systems</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Tseng, Hsin-Wu; Fan, Jiahua; Kupinski, Matthew A. 2016-01-01 Abstract. The use of a channelization mechanism on model observers not only makes mimicking human visual behavior possible, but also reduces the amount of image data needed to estimate the model observer parameters. The channelized Hotelling observer (CHO) and channelized scanning linear observer (CSLO) have recently been used to assess CT image quality for detection tasks and combined detection/estimation tasks, respectively. Although the use of channels substantially reduces the amount of data required to compute image quality, the number of scans required for CT imaging is still not practical for routine use. It is our desire to further reduce the number of scans required to make CHO or CSLO an image quality tool for routine and frequent system validations and evaluations. This work explores different data-reduction schemes and designs an approach that requires only a few CT scans. Three different kinds of approaches are included in this study: a conventional CHO/CSLO technique with a large sample size, a conventional CHO/CSLO technique with fewer samples, and an approach that we will show requires fewer samples to mimic conventional performance with a large sample size. The mean value and standard deviation of areas under ROC/EROC curve were estimated using the well-validated shuffle approach. The results indicate that an 80% data reduction can be achieved without loss of accuracy. This substantial data reduction is a step toward a practical tool for routine-task-based QA/QC CT system assessment. PMID:27493982 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss030e010008.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss030e010008.html">Earth Observations taken by Expedition 30 crewmember</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-12-04 ISS030-E-010008 (4 Dec. 2011) --- One of the Expedition 30 crew members aboard the Earth-orbiting International Space Station photographed this night time scene of the Iberian Peninsula on Dec. 4, 2011. The city lights of Spain and Portugal define the peninsula. Several large metropolitan areas are visible, marked by their relatively large and brightly lit areas, such as two capital cities -- Madrid, Spain, located near the center of the peninsula?s interior, and Lisbon, Portugal, located along the southwestern coastline. Ancient Seville, visible at image right to the north of the approximately 14 kilometer-wide Strait of Gibraltar, is one of the largest cities in Spain. All together, the Principality of Andorra, the Kingdom of Spain and the Portuguese Republic total approximately 590,000 square kilometers of landmass. The peninsula is bounded by the Atlantic Ocean to the northwest, west, and southwest and the Mediterranean Sea to the east. Its northeastern boundary with the rest of continental Europe is marked by the Pyrenees mountain range. The view is looking outwards from the orbital outpost toward the east. The network of smaller cities and towns in the interior and along the coastline attest to the large extent of human presence on the Iberian landscape. Blurring of the city lights is caused by thin cloud cover (image left and center), while the cloud tops are dimly illuminated by moonlight. Though obscured, the lights of France are visible near the horizon line at image upper left, while the lights of northern Africa are more clearly discernable at image right. The gold to green line of airglow, caused by excitation of upper atmosphere gas molecules by ultraviolet radiation, parallels the horizon line (or Earth limb). </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.458.3248S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.458.3248S">The advantages of using a Lucky Imaging camera for observations of microlensing events</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sajadian, Sedighe; Rahvar, Sohrab; Dominik, Martin; Hundertmark, Markus 2016-05-01 In this work, we study the advantages of using a Lucky Imaging camera for the observations of potential planetary microlensing events. Our aim is to reduce the blending effect and enhance exoplanet signals in binary lensing systems composed of an exoplanet and the corresponding parent star. We simulate planetary microlensing light curves based on present microlensing surveys and follow-up telescopes where one of them is equipped with a Lucky Imaging camera. This camera is used at the Danish 1.54-m follow-up telescope. Using a specific observational strategy, for an Earth-mass planet in the resonance regime, where the detection probability in crowded fields is smaller, Lucky Imaging observations improve the detection efficiency which reaches 2 per cent. Given the difficulty of detecting the signal of an Earth-mass planet in crowded-field imaging even in the resonance regime with conventional cameras, we show that Lucky Imaging can substantially improve the detection efficiency. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930044726&hterms=Low+vision&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DLow%2Bvision','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930044726&hterms=Low+vision&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DLow%2Bvision">Image enhancement filters significantly improve reading performance for low vision observers</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Lawton, T. B. 1992-01-01 As people age, so do their photoreceptors; many photoreceptors in central vision stop functioning when a person reaches their late sixties or early seventies. Low vision observers with losses in central vision, those with age-related maculopathies, were studied. Low vision observers no longer see high spatial frequencies, being unable to resolve fine edge detail. We developed image enhancement filters to compensate for the low vision observer's losses in contrast sensitivity to intermediate and high spatial frequencies. The filters work by boosting the amplitude of the less visible intermediate spatial frequencies. The lower spatial frequencies. These image enhancement filters not only reduce the magnification needed for reading by up to 70 percent, but they also increase the observer's reading speed by 2-4 times. A summary of this research is presented. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ESS.....2.2101D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ESS.....2.2101D">Exploring Hitherto Uncharted Planet Territory with Lucky-imaging Microlensing Observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Dominik, Martin; Jørgensen, U. G.; Hessman, F. V.; Horne, K.; Harpsøe, K.; Skottfelt, J.; MiNDSTEp Consortium 2011-09-01 Leading the agenda for pushing the planet sensitivity limit towards the mass of the Moon, we will report first results from our 2011 MiNDSTEp (Microlensing Network for the Detection of Small Terrestrial Exoplanets) lucky-imaging microlensing follow-up campaign with the Danish 1.54m at ESO La Silla. It serves as a precursor to observations with a global network comprising the LCOGT/SUPAscope, SONG, and MONET 1m-class robotic telescope networks gradually deployed from 2011 to 2014. As for observations from space, the lucky-imaging technique allows us to get around the atmospheric image blurring and to obtain a resolution near the diffraction limit. This enables high-precision photometry on considerably fainter (smaller) stars in the crowded fields towards the Galactic bulge than obtainable from ground-based surveys. Monitoring smaller source stars in turn provides sensitivity to planets with smaller masses orbiting the lens star. M.D. is supported by a Royal Society University Research Fellowship </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998IAUS..185..453N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998IAUS..185..453N">MHD oscillations observed in the solar photosphere with the Michelson Doppler Imager</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Norton, A.; Ulrich, R. K.; Bogart, R. S.; Bush, R. I.; Hoeksema, J. T. Magnetohydrodynamic oscillations are observed in the solar photosphere with the Michelson Doppler Imager (MDI). Images of solar surface velocity and magnetic field strength with 4'' spatial resolution and a 60 second temporal resolution are analyzed. A two dimensional gaussian aperture with a FWHM of 10'' is applied to the data in regions of sunspot, plage and quiet sun and the resulting averaged signal is returned each minute. Significant power is observed in the magnetic field oscillations with periods of five minutes. The effect of misregistration between MDI's left circularly polarized (LCP) and right circularly polarized (RCP) images has been investigated and is found not to be the cause of the observed magnetic oscillations. It is assumed that the large amplitude acoustic waves with 5 minute periods are the driving mechanism behind the magnetic oscillations. The nature of the magnetohydrodynamic oscillations are characterized by their phase relations with simultaneously observed solar surface velocity oscillations. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900027756&hterms=nonimaging&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnonimaging','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900027756&hterms=nonimaging&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dnonimaging">Simultaneous multi-frequency imaging observations of solar microwave bursts</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kundu, M. R.; White, S. M.; Schmahl, E. J. 1989-01-01 The results of simultaneous two-frequency imaging observations of solar microwave bursts with the Very Large Array are reviewed. Simultaneous 2 and 6 cm observations have been made of bursts which are optically thin at both frequencies, or optically thick at the lower frequency. In the latter case, the source structure may differ at the two frequencies, but the two sources usually seem to be related. However, this is not always true of simultaneous 6 and 20 cm observations. The results have implications for the analysis of nonimaging radio data of solar and stellar flares. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006A%26A...452..119O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006A%26A...452..119O">ESO imaging survey: infrared observations of CDF-S and HDF-S</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Olsen, L. F.; Miralles, J.-M.; da Costa, L.; Benoist, C.; Vandame, B.; Rengelink, R.; Rité, C.; Scodeggio, M.; Slijkhuis, R.; Wicenec, A.; Zaggia, S. 2006-06-01 This paper presents infrared data obtained from observations carried out at the ESO 3.5 m New Technology Telescope (NTT) of the Hubble Deep Field South (HDF-S) and the Chandra Deep Field South (CDF-S). These data were taken as part of the ESO Imaging Survey (EIS) program, a public survey conducted by ESO to promote follow-up observations with the VLT. In the HDF-S field the infrared observations cover an area of ~53 square arcmin, encompassing the HST WFPC2 and STIS fields, in the JHKs passbands. The seeing measured in the final stacked images ranges from 0.79 arcsec to 1.22 arcsec and the median limiting magnitudes (AB system, 2'' aperture, 5σ detection limit) are J_AB˜23.0, H_AB˜22.8 and K_AB˜23.0 mag. Less complete data are also available in JKs for the adjacent HST NICMOS field. For CDF-S, the infrared observations cover a total area of ~100 square arcmin, reaching median limiting magnitudes (as defined above) of J_AB˜23.6 and K_AB˜22.7 mag. For one CDF-S field H band data are also available. This paper describes the observations and presents the results of new reductions carried out entirely through the un-supervised, high-throughput EIS Data Reduction System and its associated EIS/MVM C++-based image processing library developed, over the past 5 years, by the EIS project and now publicly available. The paper also presents source catalogs extracted from the final co-added images which are used to evaluate the scientific quality of the survey products, and hence the performance of the software. This is done comparing the results obtained in the present work with those obtained by other authors from independent data and/or reductions carried out with different software packages and techniques. The final science-grade catalogs together with the astrometrically and photometrically calibrated co-added images are available at CDS. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28120394','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28120394">Comparing the Scoring of Human Decomposition from Digital Images to Scoring Using On-site Observations.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Dabbs, Gretchen R; Bytheway, Joan A; Connor, Melissa 2017-09-01 When in forensic casework or empirical research in-person assessment of human decomposition is not possible, the sensible substitution is color photographic images. To date, no research has confirmed the utility of color photographic images as a proxy for in situ observation of the level of decomposition. Sixteen observers scored photographs of 13 human cadavers in varying decomposition stages (PMI 2-186 days) using the Total Body Score system (total n = 929 observations). The on-site TBS was compared with recorded observations from digital color images using a paired samples t-test. The average difference between on-site and photographic observations was -0.20 (t = -1.679, df = 928, p = 0.094). Individually, only two observers, both students with <1 year of experience, demonstrated TBS statistically significantly different than the on-site value, suggesting that with experience, observations of human decomposition based on digital images can be substituted for assessments based on observation of the corpse in situ, when necessary. © 2017 American Academy of Forensic Sciences. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AAS...198.2103C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AAS...198.2103C">Polarization Observations with the Cosmic Background Imager</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Cartwright, J. K.; Padin, S.; Pearson, T. J.; Readhead, A. C. S.; Shepherd, M. C.; Taylor, G. B. 2001-05-01 We describe polarization observations of the CMBR with the Cosmic Background Imager, a 13 element interferometer which operates in the 26-36 GHz band from a site at 5000m in northern Chile. The array consists of 90-cm Cassegrain antennas mounted on a single, fully steerable platform; this platform can be rotated about the optical axis to facilitate polarization observations. The CBI employs single mode circularly polarized receivers, of which 12 are configured for LCP and one is configured for RCP. The 12 cross polarized baselines sample multipoles from l 600 to l 3500. The instrumental polarization of the CBI was calibrated with observations of 3C279, a bright polarized source which is unresolved by the CBI. Because the centimeter flux of 3C279 is variable, it was monitored twice per month for 8 months in 2000 with the VLA at 22 and 43 GHz. These observations also established the stability of the polarization characteristics of the CBI. This work was made possible by NSF grant AST-9802989 </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ApJ...852...79Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ApJ...852...79Y">Two Solar Tornadoes Observed with the Interface Region Imaging Spectrograph</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Yang, Zihao; Tian, Hui; Peter, Hardi; Su, Yang; Samanta, Tanmoy; Zhang, Jingwen; Chen, Yajie 2018-01-01 The barbs or legs of some prominences show an apparent motion of rotation, which are often termed solar tornadoes. It is under debate whether the apparent motion is a real rotating motion, or caused by oscillations or counter-streaming flows. We present analysis results from spectroscopic observations of two tornadoes by the Interface Region Imaging Spectrograph. Each tornado was observed for more than 2.5 hr. Doppler velocities are derived through a single Gaussian fit to the Mg II k 2796 Å and Si IV 1393 Å line profiles. We find coherent and stable redshifts and blueshifts adjacent to each other across the tornado axes, which appears to favor the interpretation of these tornadoes as rotating cool plasmas with temperatures of 104 K–105 K. This interpretation is further supported by simultaneous observations of the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, which reveal periodic motions of dark structures in the tornadoes. Our results demonstrate that spectroscopic observations can provide key information to disentangle different physical processes in solar prominences. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9037E..0LK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9037E..0LK">Observer assessment of multi-pinhole SPECT geometries for prostate cancer imaging: a simulation study</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kalantari, Faraz; Sen, Anando; Gifford, Howard C. 2014-03-01 SPECT imaging using In-111 ProstaScint is an FDA-approved method for diagnosing prostate cancer metastases within the pelvis. However, conventional medium-energy parallel-hole (MEPAR) collimators produce poor image quality and we are investigating the use of multipinhole (MPH) imaging as an alternative. This paper presents a method for evaluating MPH designs that makes use of sampling-sensitive (SS) mathematical model observers for tumor detectionlocalization tasks. Key to our approach is the redefinition of a normal (or background) reference image that is used with scanning model observers. We used this approach to compare different MPH configurations for the task of small-tumor detection in the prostate and surrounding lymph nodes. Four configurations used 10, 20, 30, and 60 pinholes evenly spaced over a complete circular orbit. A fixed-count acquisition protocol was assumed. Spherical tumors were placed within a digital anthropomorphic phantom having a realistic Prostascint biodistribution. Imaging data sets were generated with an analytical projector and reconstructed volumes were obtained with the OSEM algorithm. The MPH configurations were compared in a localization ROC (LROC) study with 2D pelvic images and both human and model observers. Regular and SS versions of the scanning channelized nonprewhitening (CNPW) and visual-search (VS) model observers were applied. The SS models demonstrated the highest correlations with the average human-observer results </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9787E..0JK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9787E..0JK">The potential of pigeons as surrogate observers in medical image perception studies</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Krupinski, Elizabeth A.; Levenson, Richard M.; Navarro, Victor; Wasserman, Edward A. 2016-03-01 Assessment of medical image quality and how changes in image appearance impact performance are critical but assessment can be expensive and time-consuming. Could an animal (pigeon) observer with well-known visual skills and documented ability to distinguish complex visual stimuli serve as a surrogate for the human observer? Using sets of whole slide pathology (WSI) and mammographic images we trained pigeons (cohorts of 4) to detect and/or classify lesions in medical images. Standard training methods were used. A chamber equipped with a 15' display with a resistive touchscreen was used to display the images and record responses (pecks). Pigeon pellets were dispensed for correct responses. The pigeons readily learned to distinguish benign from malignant breast cancer histopathology in WSI (mean % correct responses rose 50% to 85% over 15 days) and generalized readily from 4X to 10X and 20X magnifications; to detect microcalcifications (mean % correct responses rose 50% to over 85% over 25 days); to distinguish benign from malignant breast masses (3 of 4 birds learned this task to around 80% and 60% over 10 days); and ignore compression artifacts in WSI (performance with uncompressed slides averaged 95% correct; 15:1 and 27:1 compression slides averaged 92% and 90% correct). Pigeons models may help us better understand medical image perception and may be useful in quality assessment by serving as surrogate observers for certain types of studies. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active">15</li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active">16</li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9014T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9014T">Observing hydrological processes: recent advancements in surface flow monitoring through image analysis</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tauro, Flavia; Grimaldi, Salvatore 2017-04-01 Recently, several efforts have been devoted to the design and development of innovative, and often unintended, approaches for the acquisition of hydrological data. Among such pioneering techniques, this presentation reports recent advancements towards the establishment of a novel noninvasive and potentially continuous methodology based on the acquisition and analysis of images for spatially distributed observations of the kinematics of surface waters. The approach aims at enabling rapid, affordable, and accurate surface flow monitoring of natural streams. Flow monitoring is an integral part of hydrological sciences and is essential for disaster risk reduction and the comprehension of natural phenomena. However, water processes are inherently complex to observe: they are characterized by multiscale and highly heterogeneous phenomena which have traditionally demanded sophisticated and costly measurement techniques. Challenges in the implementation of such techniques have also resulted in lack of hydrological data during extreme events, in difficult-to-access environments, and at high temporal resolution. By combining low-cost yet high-resolution images and several velocimetry algorithms, noninvasive flow monitoring has been successfully conducted at highly heterogeneous scales, spanning from rills to highly turbulent streams, and medium-scale rivers, with minimal supervision by external users. Noninvasive image data acquisition has also afforded observations in high flow conditions. Latest novelties towards continuous flow monitoring at the catchment scale have entailed the development of a remote gauge-cam station on the Tiber River and integration of flow monitoring through image analysis with unmanned aerial systems (UASs) technology. The gauge-cam station and the UAS platform both afford noninvasive image acquisition and calibration through an innovative laser-based setup. Compared to traditional point-based instrumentation, images allow for generating surface </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSA33A2419V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSA33A2419V">Investigating middle-atmospheric gravity waves associated with a sprite-producing mesoscale convective event</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Vollmer, D. R.; McHarg, M. G.; Harley, J.; Haaland, R. K.; Stenbaek-Nielsen, H. 2016-12-01 On 23 July 2014, a mesoscale convective event over western Nebraska produced a large number of sprites. One frame per second images obtained from a low-noise Andor Scientific CMOS camera showed regularly-spaced horizontal striations in the airglow both before and during several of the sprite events, suggesting the presence of vertically-propagating gravity waves in the middle atmosphere. Previous work hypothesized that the gravity waves were produced by the thunderstorm itself. We compare our observations with previous work, and present numerical simulations conducted to determine source, structure, and propagation of atmospheric gravity waves. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Ap%26SS.358...25G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Ap%26SS.358...25G">Improved SOT (Hinode mission) high resolution solar imaging observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Goodarzi, H.; Koutchmy, S.; Adjabshirizadeh, A. 2015-08-01 We consider the best today available observations of the Sun free of turbulent Earth atmospheric effects, taken with the Solar Optical Telescope (SOT) onboard the Hinode spacecraft. Both the instrumental smearing and the observed stray light are analyzed in order to improve the resolution. The Point Spread Function (PSF) corresponding to the blue continuum Broadband Filter Imager (BFI) near 450 nm is deduced by analyzing (i) the limb of the Sun and (ii) images taken during the transit of the planet Venus in 2012. A combination of Gaussian and Lorentzian functions is selected to construct a PSF in order to remove both smearing due to the instrumental diffraction effects (PSF core) and the large-angle stray light due to the spiders and central obscuration (wings of the PSF) that are responsible for the parasitic stray light. A Max-likelihood deconvolution procedure based on an optimum number of iterations is discussed. It is applied to several solar field images, including the granulation near the limb. The normal non-magnetic granulation is compared to the abnormal granulation which we call magnetic. A new feature appearing for the first time at the extreme- limb of the disk (the last 100 km) is discussed in the context of the definition of the solar edge and of the solar diameter. A single sunspot is considered in order to illustrate how effectively the restoration works on the sunspot core. A set of 125 consecutive deconvolved images is assembled in a 45 min long movie illustrating the complexity of the dynamical behavior inside and around the sunspot. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22654012-tu-fg-validation-channelized-hotelling-observer-optimize-chest-radiography-image-processing-nodule-detection-human-observer-study','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22654012-tu-fg-validation-channelized-hotelling-observer-optimize-chest-radiography-image-processing-nodule-detection-human-observer-study">TU-FG-209-11: Validation of a Channelized Hotelling Observer to Optimize Chest Radiography Image Processing for Nodule Detection: A Human Observer Study</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Sanchez, A; Little, K; Chung, J Purpose: To validate the use of a Channelized Hotelling Observer (CHO) model for guiding image processing parameter selection and enable improved nodule detection in digital chest radiography. Methods: In a previous study, an anthropomorphic chest phantom was imaged with and without PMMA simulated nodules using a GE Discovery XR656 digital radiography system. The impact of image processing parameters was then explored using a CHO with 10 Laguerre-Gauss channels. In this work, we validate the CHO’s trend in nodule detectability as a function of two processing parameters by conducting a signal-known-exactly, multi-reader-multi-case (MRMC) ROC observer study. Five naive readers scored confidencemore » of nodule visualization in 384 images with 50% nodule prevalence. The image backgrounds were regions-of-interest extracted from 6 normal patient scans, and the digitally inserted simulated nodules were obtained from phantom data in previous work. Each patient image was processed with both a near-optimal and a worst-case parameter combination, as determined by the CHO for nodule detection. The same 192 ROIs were used for each image processing method, with 32 randomly selected lung ROIs per patient image. Finally, the MRMC data was analyzed using the freely available iMRMC software of Gallas et al. Results: The image processing parameters which were optimized for the CHO led to a statistically significant improvement (p=0.049) in human observer AUC from 0.78 to 0.86, relative to the image processing implementation which produced the lowest CHO performance. Conclusion: Differences in user-selectable image processing methods on a commercially available digital radiography system were shown to have a marked impact on performance of human observers in the task of lung nodule detection. Further, the effect of processing on humans was similar to the effect on CHO performance. Future work will expand this study to include a wider range of detection/classification tasks and </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910011702&hterms=tokyo+round+japan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtokyo%2Bround%2Bjapan','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910011702&hterms=tokyo+round+japan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtokyo%2Bround%2Bjapan">Optical and near-IR imaging observations of comet Austin 1989c1</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Watanabe, J.; Hiromoto, N.; Takami, H.; Aoki, TE.; Nakamura, T.; Takagishi, K.; Hatsukade, I.; Isobe, S.; Sasaki, G.; Sugai, H. 1990-01-01 Near-nucleus imaging observations of comet Austin (1989c1) were carried out by the Japanese CCD imaging team. Six telescopes were used to monitor the time variation of the near-nucleus images in C2, CN, H2O, and Na continuum in the optical region, and in J, H, and K bands in the near-IR region. A featureless, round shape of the comet was revealed in all images. Although some of the jet features are recognized by using an image enhancement technique, the azimuthal difference of the intensity distribution is about 10 percent. The images in the H2O band show complex ion structures near the nucleus. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/2134793','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/2134793">[Observation of oral actions using digital image processing system].</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Ichikawa, T; Komoda, J; Horiuchi, M; Ichiba, H; Hada, M; Matsumoto, N 1990-04-01 A new digital image processing system to observe oral actions is proposed. The system provides analyses of motion pictures along with other physiological signals. The major components are a video tape recorder, a digital image processor, a percept scope, a CCD camera, an A/D converter and a personal computer. Five reference points were marked on the lip and eyeglasses of 9 adult subjects. Lip movements were recorded and analyzed using the system when uttering five vowels and [ka, sa, ta, ha, ra, ma, pa, ba[. 1. Positions of the lip when uttering five vowels were clearly classified. 2. Active articulatory movements of the lip were not recognized when uttering consonants [k, s, t, h, r[. It seemed lip movements were dependent on tongue and mandibular movements. Downward and rearward movements of the upper lip, and upward and forward movements of the lower lip were observed when uttering consonants [m, p, b[. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017yCat..51530071F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017yCat..51530071F">VizieR Online Data Catalog: Kepler follow-up observation program. I. Imaging (Furlan+, 2017)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Furlan, E.; Ciardi, D. R.; Everett, M. E.; Saylors, M.; Teske, J. K.; Horch, E. P.; Howell, S. B.; van Belle, G. T.; Hirsch, L. A.; Gautier, T. N.; Adams, E. R.; Barrado, D.; Cartier, K. M. S.; Dressing, C. D.; Dupree, A. K.; Gilliland, R. L.; Lillo-Box, J.; Lucas, P. W.; Wang, J. 2017-07-01 We present results from six years of follow-up imaging observations of KOI host stars, including work done by teams from the Kepler Community Follow-up Observation Program (CFOP; https://exofop.ipac.caltech.edu/cfop.php) and by other groups. Several observing facilities were used to obtain high-resolution images of KOI host stars. Table1 lists the various telescopes, instruments used, filter bandpasses, typical Point Spread Function (PSF) widths, number of targets observed, and main references for the published results. The four main observing techniques employed are adaptive optics (Keck, Palomar, Lick, MMT), speckle interferometry (Gemini North, WIYN, DCT), lucky imaging (Calar Alto), and imaging from space with HST. A total of 3557 KOI host stars were observed at 11 facilities with 9 different instruments, using filters from the optical to the near-infrared. In addition, 10 of these stars were also observed at the 8m Gemini North telescope by Ziegler et al. 2016 (AJ accepted, arXiv:1605.03584) using laser guide star adaptive optics. The largest number of KOI host stars (3320) were observed using Robo-AO at the Palomar 1.5m telescope (Baranec et al. 2014ApJ...790L...8B; Baranec et al. 2016, Cat. J/AJ/152/18; Law et al. 2014, Cat. J/ApJ/791/35; Ziegler et al. 2016, AJ accepted, arXiv:1605.03584). A total of 8332 observations were carried out from 2009 September to 2015 October covering 3557 stars. We carried out observations at the Keck, Palomar, and Lick Observatory using the facility adaptive optics systems and near-infrared cameras from 2009 to 2015. At Keck, we observed with the 10m Keck II telescope and Near-Infrared Camera, second generation (NIRC2). The pixel scale of NIRC2 was 0.01''/pixel, resulting in a field of view of about 10''*10''. We observed our targets in a narrow K-band filter, Brγ, which has a central wavelength of 2.1686μm. In most cases, when a companion was detected, we also observed the target in a narrow-band J filter, Jcont, which is </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9037E..0OT','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9037E..0OT">Design of a practical model-observer-based image quality assessment method for CT imaging systems</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tseng, Hsin-Wu; Fan, Jiahua; Cao, Guangzhi; Kupinski, Matthew A.; Sainath, Paavana 2014-03-01 The channelized Hotelling observer (CHO) is a powerful method for quantitative image quality evaluations of CT systems and their image reconstruction algorithms. It has recently been used to validate the dose reduction capability of iterative image-reconstruction algorithms implemented on CT imaging systems. The use of the CHO for routine and frequent system evaluations is desirable both for quality assurance evaluations as well as further system optimizations. The use of channels substantially reduces the amount of data required to achieve accurate estimates of observer performance. However, the number of scans required is still large even with the use of channels. This work explores different data reduction schemes and designs a new approach that requires only a few CT scans of a phantom. For this work, the leave-one-out likelihood (LOOL) method developed by Hoffbeck and Landgrebe is studied as an efficient method of estimating the covariance matrices needed to compute CHO performance. Three different kinds of approaches are included in the study: a conventional CHO estimation technique with a large sample size, a conventional technique with fewer samples, and the new LOOL-based approach with fewer samples. The mean value and standard deviation of area under ROC curve (AUC) is estimated by shuffle method. Both simulation and real data results indicate that an 80% data reduction can be achieved without loss of accuracy. This data reduction makes the proposed approach a practical tool for routine CT system assessment. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4812350A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4812350A">Analyzing Serendipitous Asteroid Observations in Imaging Data using PHOTOMETRYPIPELINE</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ard, Christopher; Mommert, Michael; Trilling, David E. 2016-10-01 Asteroids are nearly ubiquitous in the night sky, making them present in the majority of imaging data taken every night. Serendipitous asteroid observations represent a treasure trove to Solar System researchers: accurate positional measurements of asteroids provide important constraints on their sometimes highly uncertain orbits, whereas calibrated photometric measurements can be used to establish rotational periods, intrinsic colors, or photometric phase curves.We present an add-on to the PHOTOMETRYPIPELINE (PP, github.com/mommermi/photometrypipeline, see Poster presentation 123.42) that identifies asteroids that have been observed serendipitously and extracts astrometry and calibrated photometry for these objects. PP is an open-source Python 2.7 software suite that provides image registration, aperture photometry, photometric calibration, and target identification with only minimal human interaction.Asteroids are identified based on approximate positions that are pre-calculated for a range of dates. Using interpolated coordinates, we identify potential asteroids that might be in the observed field and query their exact positions and positional uncertainties from the JPL Horizons system. The method results in robust astrometry and calibrated photometry for all asteroids in the field as a function of time. Our measurements will supplement existing photometric databases of asteroids and improve their orbits.We present first results using this procedure based on imaging data from the Vatican Advanced Technology Telescope.This work was done in the framework of NAU's REU summer program that is supported by NSF grant AST-1461200. PP was developed in the framework of the "Mission Accessible Near-Earth Object Survey" (MANOS) and is supported by NASA SSO grants NNX15AE90G and NNX14AN82G. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AdSpR..27.1165W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AdSpR..27.1165W">Observations of OH(3,1) airglow emission using a Michelson interferometer at 62° S</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Won, Young-In; Cho, Young-Min; Niciejewski, Rick J.; Kim, Jhoon A Michelson interferometer was used to observe the hydroxyl (OH) emission in the upper mesosphere at the King Sejong Station (62.22° S, 301.25° E), Antarctica. The instrument was installed in February 1999 and has been in routine operation since then. An intensive operational effort has resulted in a substantial data set between April and June, 1999. A spectral analysis was performed on individual data to examine the information of dominant waves. A harmonic analysis was also carried out on the monthly average data to investigate the characteristics of the major low frequency oscillations. The 12-hr temperature oscillations exhibit a striking agreement with a theoretical tidal model, supporting the tidal (migrating) origin. The 8-hr wave is found to be persistent and dominant, reflecting its major role in the upper mesospheric dynamics at the given latitude. The 6-hr oscillation is observed only in May with its value close to the prediction for zonally symmetric tides. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880037707&hterms=sars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsars','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880037707&hterms=sars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsars">Observation of sea-ice dynamics using synthetic aperture radar images: Automated analysis</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Vesecky, John F.; Samadani, Ramin; Smith, Martha P.; Daida, Jason M.; Bracewell, Ronald N. 1988-01-01 The European Space Agency's ERS-1 satellite, as well as others planned to follow, is expected to carry synthetic-aperture radars (SARs) over the polar regions beginning in 1989. A key component in utilization of these SAR data is an automated scheme for extracting the sea-ice velocity field from a time sequence of SAR images of the same geographical region. Two techniques for automated sea-ice tracking, image pyramid area correlation (hierarchical correlation) and feature tracking, are described. Each technique is applied to a pair of Seasat SAR sea-ice images. The results compare well with each other and with manually tracked estimates of the ice velocity. The advantages and disadvantages of these automated methods are pointed out. Using these ice velocity field estimates it is possible to construct one sea-ice image from the other member of the pair. Comparing the reconstructed image with the observed image, errors in the estimated velocity field can be recognized and a useful probable error display created automatically to accompany ice velocity estimates. It is suggested that this error display may be useful in segmenting the sea ice observed into regions that move as rigid plates of significant ice velocity shear and distortion. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010019249','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010019249">Earth Observing-1 Advanced Land Imager: Radiometric Response Calibration</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Mendenhall, J. A.; Lencioni, D. E.; Evans, J. B. 2000-01-01 The Advanced Land Imager (ALI) is one of three instruments to be flown on the first Earth Observing mission (EO-1) under NASA's New Millennium Program (NMP). ALI contains a number of innovative features, including a wide field of view optical design, compact multispectral focal plane arrays, non-cryogenic HgCdTe detectors for the short wave infrared bands, and silicon carbide optics. This document outlines the techniques adopted during ground calibration of the radiometric response of the Advanced Land Imager. Results from system level measurements of the instrument response, signal-to-noise ratio, saturation radiance, and dynamic range for all detectors of every spectral band are also presented. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss041e067595.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss041e067595.html">Earth Observations taken by Expedition 41 crewmember.</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2014-10-06 ISS041-E-067595 (6 Oct. 2014) --- This moonlit panorama was shot recently with a wide-angle lens by an Expedition 41 crew member aboard the International Space Station, as they looked southwest from a point over Nebraska. The wide-angle lens shows a huge swath of country that stretches from Portland, Oregon (right) to Phoenix, Arizona (left). The largest string of lights is the Ogden-Salt Lake City-Provo area (lower center) in Utah. The Los Angeles and San Francisco metropolitan regions, and the cities of the central valley of California (Bakersfield to Redding) stretch across the horizon. The green airglow layer always appears in night images. Moonlight shows the red tinge of the space station?s solar arrays top left. Moonlight emphasizes the broader-scale geological zones. Nevada?s short, dark, parallel mountain ranges of the basin and range geological province (center) contrast with the expanses of flat terrain of the Colorado Plateau (left) in Colorado, Arizona, Utah and New Mexico. The near-full moon even reveals the vast dry lake bed known as the Bonneville Salt Flats. The black line of the Sierra Nevada marks the edge of California?s well-lit central valley (directly below the San Francisco Bay area). </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910069026&hterms=L37&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DL37','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910069026&hterms=L37&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DL37">Observations of Comet Levy (1990c) with the Hopkins Ultraviolet Telescope</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Feldman, P. D.; Davidsen, A. F.; Blair, W. P.; Bowers, C. W.; Dixon, W. V.; Durrance, S. T.; Henry, R. C.; Ferguson, H. C.; Kimble, R. A.; Gull, Theodore R. 1991-01-01 Observations of Comet Levy (1990c) were made with the Hopkins Ultraviolet Telescope during the Astro-1 Space Shuttle mission on December 10, 1990. The spectrum, covering the wavelength range 415-1850 A at a spectral resolution of 3 A, shows the presence of carbon monoxide and atomic hydrogen, carbon, and sulfur in the coma. Aside from H I Lyman-beta, no cometary features are detected below 1200 A, although cometary O I and O II would be masked by the same emissions present in the day airglow spectrum. The 9.4 x 116 arcsecond aperture corresponds to 12,000 x 148,000 km at the comet. The derived production rate of CO relative to water is 0.11 + or - 0.02, compared with 0.04 + or - 0.01 derived from IUE observations (made in September 1990) which sample a much smaller region of the coma. This suggests the presence of an extended source of CO, as was found in comet Halley. Upper limits on Ne and Ar abundance are within one order of magnitude of solar abundances. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSA12A..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSA12A..08S">Remote sensing of the low-latitude daytime ionosphere: ICON simulations and retrievals</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Stephan, A. W.; Korpela, E.; England, S.; Immel, T. J. 2016-12-01 The Ionospheric Connection Explorer (ICON) sensor suite includes a spectrograph that will provide altitude profiles of the OII 61.7 and 83.4 nm airglow features, from which the daytime F-region ionosphere can be inferred. To make the connection between these extreme-ultraviolet (EUV) airglow emissions and ionospheric densities, ICON will use a method that has matured significantly in the last decade with the analysis of data from the Remote Atmospheric and Ionospheric Detection System (RAIDS) on the International Space Station, and the Special Sensor Ultraviolet Limb Imager (SSULI) sensors on the Defense Meteorological Satellite Program (DMSP) series of satellites. We will present end-to-end simulations of ICON EUV airglow measurements and data inversion for the expected viewing geometry and sensor capabilities, including noise. While we will focus on the performance of the algorithm for ICON within the context of the current state of knowledge, we will also identify areas where fundamental information can be gained from the high-sensitivity ICON measurements that could be used as feedback to directly improve the overall performance of the algorithm itself. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24514183','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24514183">Nonlinear regression method for estimating neutral wind and temperature from Fabry-Perot interferometer data.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Harding, Brian J; Gehrels, Thomas W; Makela, Jonathan J 2014-02-01 The Earth's thermosphere plays a critical role in driving electrodynamic processes in the ionosphere and in transferring solar energy to the atmosphere, yet measurements of thermospheric state parameters, such as wind and temperature, are sparse. One of the most popular techniques for measuring these parameters is to use a Fabry-Perot interferometer to monitor the Doppler width and breadth of naturally occurring airglow emissions in the thermosphere. In this work, we present a technique for estimating upper-atmospheric winds and temperatures from images of Fabry-Perot fringes captured by a CCD detector. We estimate instrument parameters from fringe patterns of a frequency-stabilized laser, and we use these parameters to estimate winds and temperatures from airglow fringe patterns. A unique feature of this technique is the model used for the laser and airglow fringe patterns, which fits all fringes simultaneously and attempts to model the effects of optical defects. This technique yields accurate estimates for winds, temperatures, and the associated uncertainties in these parameters, as we show with a Monte Carlo simulation. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=S81-40833&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dphoto%2Bimage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=S81-40833&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dphoto%2Bimage">Earth observation photo taken by JPL with the Shuttle Imaging Radar-A</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1981-01-01 Earth observation photo taken by the Jet Propulsion Laboratory (JPL) with the Shuttle Imaging Radar-A (SIR-A). This image shows a 50 by 120 kilometer (30 by 75 mile) area of the Mediterranean Sea and the eastern coast of Central Sardinia (left). The city of Arbatose is seen as a bright area along the coast in the lower part of the image, and the star-like spot off the coast is a ship's reflection. The Gulf of Orsei is near the top of the image. Bright, mottled features in the sea (right) represent surface choppiness. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10136E..10H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10136E..10H">The disagreement between the ideal observer and human observers in hardware and software imaging system optimization: theoretical explanations and evidence</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> He, Xin 2017-03-01 The ideal observer is widely used in imaging system optimization. One practical question remains open: do the ideal and human observers have the same preference in system optimization and evaluation? Based on the ideal observer's mathematical properties proposed by Barrett et. al. and the empirical properties of human observers investigated by Myers et. al., I attempt to pursue the general rules regarding the applicability of the ideal observer in system optimization. Particularly, in software optimization, the ideal observer pursues data conservation while humans pursue data presentation or perception. In hardware optimization, the ideal observer pursues a system with the maximum total information, while humans pursue a system with the maximum selected (e.g., certain frequency bands) information. These different objectives may result in different system optimizations between human and the ideal observers. Thus, an ideal observer optimized system is not necessarily optimal for humans. I cite empirical evidence in search and detection tasks, in hardware and software evaluation, in X-ray CT, pinhole imaging, as well as emission computed tomography to corroborate the claims. (Disclaimer: the views expressed in this work do not necessarily represent those of the FDA) </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=S81-40832&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphoto%2Bimage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=S81-40832&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphoto%2Bimage">Earth observation photo taken by JPL with the Shuttle Imaging Radar-A</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1981-01-01 Earth observation photo taken by the Jet Propulsion Laboratory (JPL) with the Shuttle Imaging Radar-A (SIR-A). This image shows the Los Angeles basin. The area's freeways are visible as dark lines. The Los Angles harbor breakwater off Long Beach is seen as a bright line. Vessels in the harbor show as bright points. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3685Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3685Y">Study of medium-scale traveling ionospheric disturbances (MSTID) with sounding rockets and ground observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Yamamoto, Mamoru; Abe, Takumi; Kumamoto, Atsushi; Yokoyama, Tatsuhiro; Bernhardt, Paul; Watanabe, Shigeto; Yamamoto, Masa-yuki; Larsen, Miguel; Saito, Susumu; Tsugawa, Takuya; Ishisaka, Keigo; Iwagami, Naomoto; Nishioka, Michi; Kato, Tomohiro; Takahashi, Takao; Tanaka, Makoto; Mr Medium-scale traveling ionospheric disturbance (MSTID) is an interesting phenomenon in the F-region. The MSTID is frequent in summer nighttime over Japan, showing wave structures with wavelengths of 100-200 km, periodicity of about 1 hour, and propagation toward the southwest. The phenomena are observed by the total electron content (TEC) from GEONET, Japanese dense network of GPS receivers, and 630 nm airglow imagers as horizontal pattern. It was also measured as Spread-F events of ionograms or as field-aligned echoes of the MU radar. MSTID was, in the past, explained by Perkins instability (Perkins, 1973) while its low growth rate was a problem. Recently 3D simulation study by Yokoyama et al (2009) hypothesized a generation mechanism of the MSTID, which stands on electromagnetic E/F-region coupling of the ionosphere. The hypothesis is that the MSTID first grows with polarization electric fields from sporadic-E, then show spatial structures resembling to the Perkins instability. We recently conducted a observation campaign to check this hypothesis. We launched JASA ISAS sounding rockets S-310-42 and S-520-27 at 23:00 JST and 23:57JST on July 20, 2013 while an MSTID event was monitored in real-time by the GPS-TEC from GEONET. We found 1-5mV/m northeastward/eastward electric fields during the flight. Variation of electric fileds were associated with horizontal distribution of plasma density. Wind velocity was measured by the TME and Lithium releases from S-310-42 and S-520-27 rockets, respectively, showing southward wind near the sporadic-E layer heights. These results are consistent to the expected generation mechanism shown above. In the presentation we will discuss electric-field results and its relationship with plasma density variability together with preliminary results from the neutral-wind observations. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active">16</li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active">17</li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900013510','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900013510">Spaceborne radar observations: A guide for Magellan radar-image analysis</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Ford, J. P.; Blom, R. G.; Crisp, J. A.; Elachi, Charles; Farr, T. G.; Saunders, R. Stephen; Theilig, E. E.; Wall, S. D.; Yewell, S. B. 1989-01-01 Geologic analyses of spaceborne radar images of Earth are reviewed and summarized with respect to detecting, mapping, and interpreting impact craters, volcanic landforms, eolian and subsurface features, and tectonic landforms. Interpretations are illustrated mostly with Seasat synthetic aperture radar and shuttle-imaging-radar images. Analogies are drawn for the potential interpretation of radar images of Venus, with emphasis on the effects of variation in Magellan look angle with Venusian latitude. In each landform category, differences in feature perception and interpretive capability are related to variations in imaging geometry, spatial resolution, and wavelength of the imaging radar systems. Impact craters and other radially symmetrical features may show apparent bilateral symmetry parallel to the illumination vector at low look angles. The styles of eruption and the emplacement of major and minor volcanic constructs can be interpreted from morphological features observed in images. Radar responses that are governed by small-scale surface roughness may serve to distinguish flow types, but do not provide unambiguous information. Imaging of sand dunes is rigorously constrained by specific angular relations between the illumination vector and the orientation and angle of repose of the dune faces, but is independent of radar wavelength. With a single look angle, conditions that enable shallow subsurface imaging to occur do not provide the information necessary to determine whether the radar has recorded surface or subsurface features. The topographic linearity of many tectonic landforms is enhanced on images at regional and local scales, but the detection of structural detail is a strong function of illumination direction. Nontopographic tectonic lineaments may appear in response to contrasts in small-surface roughness or dielectric constant. The breakpoint for rough surfaces will vary by about 25 percent through the Magellan viewing geometries from low to high </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6826E..2PO','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6826E..2PO">Methods on observation of fluorescence micro-imaging for microalgae</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ou, Lin; Zhuang, Hui-ru; Chen, Rong; Lei, Jin-pin; Liao, Xiao-hua; Lin, Wen-suo 2007-11-01 Objective: Auto-fluorescence micro-imaging of microalgae are observed by using of laser scanning confocal microscopy (LSCM) and fluorescence microscopy, so as to investigate the effect of auto fluorescence alteration on growth of irradiated microalgae irradiated, meanwhile, the method of microalgae cells stained also to be studied. Methods: Platymonas subcordiformis, Phaeodactylum tricormutum and Isochyrsis zhanjiangensis cells are stained with acridine orange, and observed by fluorescence microscopy; the three types microalgae mentioned above are irradiated by Nd:YAP laser with 10w at 1341nm, irradiating time:12s, 30s, 35s and 55s, than to be cultured 6 days, and the auto fluorescence images and fluorescence spectra of algae cells are obtained by LSCM on lambda scan mode, at excitation 488nm (Ar + laser). Results: It is showed that the shapes and the structural features of microalgae cells stained can be seen clearly, and the cytoplasm and nucleus also can be observed. The chloroplasts in cell is bigger on promoting effects, conversely, it is to be mutilated, deformation and shrink. Contrast to the CK, the peak positions of fluorescence of algae cells irradiated is similar to the whole while the peak light intensity alters. On irradiation of promoting dose, however, the auto fluorescence intensity is enhanced more than control. Conclusions: The method of cell stained can be used to observed genetic material in microalgae. There are obvious effects for laser irradiating to chloroplasts in cells, the bigger chloroplasts the greater fluorescence intensity. Physiological incentive effects of microalgae irradiated can be given expression on fluorescence characteristics and fluorescence intensity alteration of cells. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000AAS...197.5502C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000AAS...197.5502C">Polarization Observations with the Cosmic Background Imager</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Cartwright, J. K.; Padin, S.; Pearson, T. J.; Readhead, A. C. S.; Shepherd, M. C.; Taylor, G. B. 2000-12-01 The linear polarization of the Cosmic Microwave Background Radiation is a fundamental prediction of the standard model. We report a limit on the polarization of the CMBR for l ~660. This limit was obtained with the Cosmic Background Imager, a 13 element interferometer which operates in the 26-36 GHz band from a site at 5000m in northern Chile. The array consists of 90-cm Cassegrain antennas mounted on a single, fully steerable platform; this platform can be rotated about the optical axis to facilitate polarization observations. The CBI employs single mode circularly polarized receivers, of which 12 are configured for LCP and one is configured for RCP. The 12 cross polarized baselines sample multipoles from l ~600 to l ~3500. The instrumental polarization of the CBI was calibrated with observations of 3C279, a bright polarized source which is unresolved by the CBI. Because the centimeter flux of 3C279 is variable, it was monitored twice per month for 8 months in '00 with the VLA at 22 and 43 GHz. These observations also established the stability of the polarization characteristics of the CBI. This work was made possible by NSF grant AST-9802989 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=S81-40829&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphoto%2Bimage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=S81-40829&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphoto%2Bimage">Earth observation photo taken by JPL with the Shuttle Imaging Radar-A</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1981-01-01 Photos of earth observations taken by the Jet Propulsion Laboratory (JPL) with the Shuttle Imaging Radar-A (SIR-A). This image shows Lake Okeechobee (right) and Lake Istokopoga (left) in Central Florida. Lake Okeechobee is bounded on the east by rectangular agricultural fields and to the south and west by swamps and wetlands which appear as bright features. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9100E..04B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9100E..04B">Performance of PHOTONIS' low light level CMOS imaging sensor for long range observation</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bourree, Loig E. 2014-05-01 Identification of potential threats in low-light conditions through imaging is commonly achieved through closed-circuit television (CCTV) and surveillance cameras by combining the extended near infrared (NIR) response (800-10000nm wavelengths) of the imaging sensor with NIR LED or laser illuminators. Consequently, camera systems typically used for purposes of long-range observation often require high-power lasers in order to generate sufficient photons on targets to acquire detailed images at night. While these systems may adequately identify targets at long-range, the NIR illumination needed to achieve such functionality can easily be detected and therefore may not be suitable for covert applications. In order to reduce dependency on supplemental illumination in low-light conditions, the frame rate of the imaging sensors may be reduced to increase the photon integration time and thus improve the signal to noise ratio of the image. However, this may hinder the camera's ability to image moving objects with high fidelity. In order to address these particular drawbacks, PHOTONIS has developed a CMOS imaging sensor (CIS) with a pixel architecture and geometry designed specifically to overcome these issues in low-light level imaging. By combining this CIS with field programmable gate array (FPGA)-based image processing electronics, PHOTONIS has achieved low-read noise imaging with enhanced signal-to-noise ratio at quarter moon illumination, all at standard video frame rates. The performance of this CIS is discussed herein and compared to other commercially available CMOS and CCD for long-range observation applications. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22522212-dynamics-disk-plumes-observed-interface-region-imaging-spectrograph-atmospheric-imaging-assembly-helioseismic-magnetic-imager','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22522212-dynamics-disk-plumes-observed-interface-region-imaging-spectrograph-atmospheric-imaging-assembly-helioseismic-magnetic-imager">DYNAMICS OF ON-DISK PLUMES AS OBSERVED WITH THE INTERFACE REGION IMAGING SPECTROGRAPH, THE ATMOSPHERIC IMAGING ASSEMBLY, AND THE HELIOSEISMIC AND MAGNETIC IMAGER</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Pant, Vaibhav; Mazumder, Rakesh; Banerjee, Dipankar 2015-07-01 We examine the role of small-scale transients in the formation and evolution of solar coronal plumes. We study the dynamics of plume footpoints seen in the vicinity of a coronal hole using the Atmospheric Imaging Assembly (AIA) images, the Helioseismic and Magnetic Imager magnetogram on board the Solar Dynamics Observatory and spectroscopic data from the Interface Region Imaging Spectrograph (IRIS). Quasi-periodic brightenings are observed in the base of the plumes and are associated with magnetic flux changes. With the high spectral and spatial resolution of IRIS, we identify the sources of these oscillations and try to understand what role themore » transients at the footpoints can play in sustaining the coronal plumes. IRIS “sit-and-stare” observations provide a unique opportunity to study the evolution of footpoints of the plumes. We notice enhanced line width and intensity, and large deviation from the average Doppler shift in the line profiles at specific instances, which indicate the presence of flows at the footpoints of plumes. We propose that outflows (jet-like features) as a result of small-scale reconnections affect the line profiles. These jet-like features may also be responsible for the generation of propagating disturbances (PDs) within the plumes, which are observed to be propagating to larger distances as recorded from multiple AIA channels. These PDs can be explained in terms of slow magnetoacoustic waves.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040074235&hterms=energy+solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Denergy%2Bsolar','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040074235&hterms=energy+solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Denergy%2Bsolar">Solar Flares Observed with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI)</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Holman, Gordon D. 2004-01-01 Solar flares are impressive examples of explosive energy release in unconfined, magnetized plasma. It is generally believed that the flare energy is derived from the coronal magnetic field. However, we have not been able to establish the specific energy release mechanism(s) or the relative partitioning of the released energy between heating, particle acceleration (electrons and ions), and mass motions. NASA's RHESSI Mission was designed to study the acceleration and evolution of electrons and ions in flares by observing the X-ray and gamma-ray emissions these energetic particles produce. This is accomplished through the combination of high-resolution spectroscopy and spectroscopic imaging, including the first images of flares in gamma rays. RHESSI has observed over 12,000 solar flares since its launch on February 5, 2002. I will demonstrate how we use the RHESSI spectra to deduce physical properties of accelerated electrons and hot plasma in flares. Using images to estimate volumes, w e typically find that the total energy in accelerated electrons is comparable to that in the thermal plasma. I will also present flare observations that provide strong support for the presence of magnetic reconnection in a large-scale, vertical current sheet in the solar corona. RHESSI observations such as these are allowing us to probe more deeply into the physics of solar flares. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24925100','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24925100">Fine structure in diabetic retinopathy lesions as observed by adaptive optics imaging. A qualitative study.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Bek, Toke 2014-12-01 Diabetic retinopathy is diagnosed by fundus photography and optical coherence tomography (OCT) scanning. However, adaptive optics (AO) imaging can be expected to add new aspects to the knowledge of diabetic retinopathy because photographic resolution is improved by reducing the influence of optical aberrations on retinal imaging. Nineteen patients with diabetes mellitus were subjected to fundus photography, OCT scanning and AO imaging. The fundus photographs were scaled to the same magnification as that of the AO image, and qualitative aspects of AO images of each retinopathy lesion observed on fundus photographs and OCT scans were assessed. All red lesions on fundus photographs appeared on AO images as dark hyporeflective elements, but it could not be verified whether lesions represented haemorrhages or microaneurysms. The smallest of these lesions were circular with a size corresponding to that of blood cells. Hard exudates had irregular surfaces with buddings of various sizes protruding from the lesions. Areas of retinal oedema observed by fundus imaging and OCT scanning resulted in blurring of AO images, but cystoid spaces observed by OCT could be seen on AO images to have a sharp delimitation with a darker hyporeflective rim at the internal lining of the cyst wall. AO imaging may potentially assist in detecting diabetic retinopathy at an earlier stage, may help elucidating the pathophysiology of the diseases and may be used for evaluating the effects of clinical interventions on diabetic retinopathy and other retinal vascular diseases. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMAE43A0245S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMAE43A0245S">Monochromatic imaging observation of sprites with the Reimei satellite</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sakanoi, T.; Adachi, T.; Sato, M.; Yamazaki, A.; Asamura, K.; Hirahara, M. 2012-12-01 The sprite emission is characterized by vertically extending fine structures (called as streamer, halo, etc.) in the approximate altitude range from 40 to 90 km. Satellite observation is useful to investigate the global distributions of sprite since an optical instrument on a satellite can measure the sprite in the wide range without atmospheric absorption. However, the sprite has been measured mainly by ground-based instruments, and there is no monochromatic imaging data from space. The multi-spectral camera (MAC) on Reimei was originally designed to measure auroral emissions in the polar region taking the monochromatic images at wavelengths of 428 nm, 558 nm, and 670 nm. Since March 2008, MAC has been operated in the mid- and low-latitudes viewing the limb direction with an exposure time of 957 ms to measure the monochromatic image of sprite emission. The spatial resolution at a tangential point is approximately 4 km. According to the noon-midnight sun-synchronous orbit of Reimei at an altitude of 640 km, the observation is made around the midnight sector. So far, we found seven sprits events in N2 1P (670 nm) images, and on six events the simultaneous observations between N2+ 1N (428nm) and N2 1P were performed. The electron temperature and electric field associated with a sprite can be estimated from the intensity ratio between emission of N2+ 1N and that of N2 1P. However, we did not obtain the N2+ 1N emission intensity due to the low sensitivity of 428 nm channel of MAC. Therefore, the N2+ 1N intensities of sprites are estimated to be less than the noise level (26 - 54 R), while the measured N2 1P intensities of sprites are 2.9 - 3.6 kR. Using these data, we estimated the upper limit of electron temperature and electric field associated with sprites. The altitude of sprite emission was accurately determined with the satellite attitude data and the field-of-view direction of MAC. On the 2008 Sep.2 case, we obtained sprite events at 26.6 GLAT and 107.6 GELON </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss030e060478.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss030e060478.html">Earth Observations taken by Expedition 30 crewmember</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2012-01-30 ISS030-E-060478 (30 Jan. 2012) --- The city lights of Madrid (just right of center) stand out in this photograph from the International Space Station. Recorded by one of the Expedition 30 crew members, the view shows almost the entire Iberian Peninsula (both Spain and Portugal) with the Strait of Gibraltar and Morocco appearing at lower left. What is thought to be a blur of the moon appears in upper left corner. The faint gold or brownish line of airglow?caused by ultraviolet radiation exciting the gas molecules in the upper atmosphere?parallels the horizon or Earth limb. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040110411&hterms=image+processing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dimage%2Bprocessing','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040110411&hterms=image+processing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dimage%2Bprocessing">Retinex Image Processing: Improved Fidelity To Direct Visual Observation</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Jobson, Daniel J.; Rahman, Zia-Ur; Woodell, Glenn A. 1996-01-01 Recorded color images differ from direct human viewing by the lack of dynamic range compression and color constancy. Research is summarized which develops the center/surround retinex concept originated by Edwin Land through a single scale design to a multi-scale design with color restoration (MSRCR). The MSRCR synthesizes dynamic range compression, color constancy, and color rendition and, thereby, approaches fidelity to direct observation. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss025e009858.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss025e009858.html">Night Earth Observation taken by the Expedition 25 crew</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2010-10-28 ISS025-E-009858 (28 Oct. 2010) --- From 220 miles above Earth, one of the Expedition 25 crew members on the International Space Station took this night time photo featuring the bright lights of Cairo and Alexandria, Egypt on the Mediterranean coast. The Nile River and its delta stand out clearly as well. On the horizon, the airglow of the atmosphere is seen across the Mediterranean. The Sinai Peninsula, at right, is outlined with lights highlighting the Gulf of Suez and Gulf of Aqaba. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20060000018','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20060000018">Solid Hydrogen Experiments for Atomic Propellants: Particle Formation, Imaging, Observations, and Analyses</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Palaszewski, Bryan 2005-01-01 This report presents particle formation observations and detailed analyses of the images from experiments that were conducted on the formation of solid hydrogen particles in liquid helium. Hydrogen was frozen into particles in liquid helium, and observed with a video camera. The solid hydrogen particle sizes and the total mass of hydrogen particles were estimated. These newly analyzed data are from the test series held on February 28, 2001. Particle sizes from previous testing in 1999 and the testing in 2001 were similar. Though the 2001 testing created similar particles sizes, many new particle formation phenomena were observed: microparticles and delayed particle formation. These experiment image analyses are some of the first steps toward visually characterizing these particles, and they allow designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA21A2503F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA21A2503F">Estimation of 557.7 nm Emission Altitude using Co-located Lidars and Photometers over Arecibo</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Franco, E.; Raizada, S.; Lautenbach, J.; Brum, C. G. M. 2017-12-01 Airglow at 557.7 nm (green line emission) is generated through the Barth mechanism in the E-region altitude and is sometimes associated with red line (630.0 nm) originating at F-region altitudes. Photons at 557.7 nm are produced through the quenching of excited atomic oxygen atoms, O(1S), while 630.0 nm results through the de-excitation of O(1D) atoms. Even though, the contribution of the green line from F-region is negligible and the significant component comes from the mesosphere, this uncertainty gives rise to a question related to its precise altitude. Previous studies have shown that perturbations generated by atmospheric gravity Waves (GWs) alter the airglow intensity and can be used for studying dynamics of the region where it originates. The uncertainty in the emission altitude of green line can be resolved by using co-located lidars, which provide altitude resolved metal densities. At Arecibo, the resonance lidars tuned to Na and K resonance wavelengths at 589 nm and 770 nm can be used in conjunction with simultaneous measurements from green line photometer to resolve this issue. Both photometer and lidars have narrow field of view as compared to airglow imagers, and hence provide an added advantage that these instruments sample same GW spectrum. Hence, correlation between density perturbations inferred from lidars and airglow intensity perturbations can shed light on the exact altitude of green line emission. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4239938','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4239938">High-Precision Image Aided Inertial Navigation with Known Features: Observability Analysis and Performance Evaluation</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Jiang, Weiping; Wang, Li; Niu, Xiaoji; Zhang, Quan; Zhang, Hui; Tang, Min; Hu, Xiangyun 2014-01-01 A high-precision image-aided inertial navigation system (INS) is proposed as an alternative to the carrier-phase-based differential Global Navigation Satellite Systems (CDGNSSs) when satellite-based navigation systems are unavailable. In this paper, the image/INS integrated algorithm is modeled by a tightly-coupled iterative extended Kalman filter (IEKF). Tightly-coupled integration ensures that the integrated system is reliable, even if few known feature points (i.e., less than three) are observed in the images. A new global observability analysis of this tightly-coupled integration is presented to guarantee that the system is observable under the necessary conditions. The analysis conclusions were verified by simulations and field tests. The field tests also indicate that high-precision position (centimeter-level) and attitude (half-degree-level)-integrated solutions can be achieved in a global reference. PMID:25330046 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22398947-experimental-observation-sub-rayleigh-quantum-imaging-two-photon-entangled-source','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22398947-experimental-observation-sub-rayleigh-quantum-imaging-two-photon-entangled-source">Experimental observation of sub-Rayleigh quantum imaging with a two-photon entangled source</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Xu, De-Qin; School of Science, Tianjin University of Technology and Education, Tianjin 300222; Song, Xin-Bing It has been theoretically predicted that N-photon quantum imaging can realize either an N-fold resolution improvement (Heisenberg-like scaling) or a √(N)-fold resolution improvement (standard quantum limit) beyond the Rayleigh diffraction bound, over classical imaging. Here, we report the experimental study on spatial sub-Rayleigh quantum imaging using a two-photon entangled source. Two experimental schemes are proposed and performed. In a Fraunhofer diffraction scheme with a lens, two-photon Airy disk pattern is observed with subwavelength diffraction property. In a lens imaging apparatus, however, two-photon sub-Rayleigh imaging for an object is realized with super-resolution property. The experimental results agree with the theoretical predictionmore » in the two-photon quantum imaging regime.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090006704&hterms=michael+porter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmichael%2Bporter','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090006704&hterms=michael+porter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmichael%2Bporter">The Sheath Transport Observer for the Redistribution of Mass (STORM) Image</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kuntz, Kip; Collier, Michael; Sibeck, David G.; Porter, F. Scott; Carter, J. A.; Cravens, Thomas; Omidi, N.; Robertson, Ina; Sembay, S.; Snowden, Steven L. 2008-01-01 All of the solar wind energy that powers magnetospheric processes passes through the magnetosheath and magnetopause. Global images of the magnetosheath and magnetopause boundary layers will resolve longstanding controversy surrounding fundamental phenomena that occur at the magnetopause and provide information needed to improve operational space weather models. Recent developments showing that soft X-rays (0.15-1 keV) result from high charge state solar wind ions undergoing charge exchange recombination through collisions with exospheric neutral atoms has led to the realization that soft X-ray imaging can provide global maps of the high-density shocked solar wind within the magnetosheath and cusps, regions lying between the lower density solar wind and magnetosphere. We discuss an instrument concept called the Sheath Transport Observer for the Redistribution of Mass (STORM), an X-ray imager suitable for simultaneously imaging the dayside magnetosheath, the magnetopause boundary layers, and the cusps. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110005606','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110005606">The Sheath Transport Observer for the Redistribution of Mass (STORM) Imager</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Collier, Michael R.; Sibeck, David G.; Porter, F. Scott; Burch, J.; Carter, J. A.; Cravens, Thomas; Kuntz, Kip; Omidi, N.; Read, A.; Robertson, Ina; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20110005606'); toggleEditAbsImage('author_20110005606_show'); toggleEditAbsImage('author_20110005606_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20110005606_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20110005606_hide"> 2010-01-01 All of the solar wind energy that powers magnetospheric processes passes through the magnetosheath and magnetopause. Global images of the magnetosheath and magnetopause boundary layers will resolve longstanding controversies surrounding fundamental phenomena that occur at the magnetopause and provide information needed to improve operational space weather models. Recent developments showing that soft X-rays (0.15-1 keV) result from high charge state solar wind ions undergoing charge exchange recombination through collisions with exospheric neutral atoms has led to the realization that soft X-ray imaging can provide global maps of the high-density shocked solar wind within the magnetosheath and cusps, regions lying between the lower density solar wind and magnetosphere. We discuss an instrument concept called the Sheath Transport Observer for the Redistribution of Mass (STORM), an X-ray imager suitable for simultaneously imaging the dayside magnetosheath, the magnetopause boundary layers, and the cusps. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9301E..3DD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9301E..3DD">Center determination for trailed sources in astronomical observation images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Du, Jun Ju; Hu, Shao Ming; Chen, Xu; Guo, Di Fu 2014-11-01 Images with trailed sources can be obtained when observing near-Earth objects, such as small astroids, space debris, major planets and their satellites, no matter the telescopes track on sidereal speed or the speed of target. The low centering accuracy of these trailed sources is one of the most important sources of the astrometric uncertainty, but how to determine the central positions of the trailed sources accurately remains a significant challenge to image processing techniques, especially in the study of faint or fast moving objects. According to the conditions of one-meter telescope at Weihai Observatory of Shandong University, moment and point-spread-function (PSF) fitting were chosen to develop the image processing pipeline for space debris. The principles and the implementations of both two methods are introduced in this paper. And some simulated images containing trailed sources are analyzed with each technique. The results show that two methods are comparable to obtain the accurate central positions of trailed sources when the signal to noise (SNR) is high. But moment tends to fail for the objects with low SNR. Compared with moment, PSF fitting seems to be more robust and versatile. However, PSF fitting is quite time-consuming. Therefore, if there are enough bright stars in the field, or the high astronometric accuracy is not necessary, moment is competent. Otherwise, the combination of moment and PSF fitting is recommended. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH51B2492B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH51B2492B">Simulating multi-spacecraft Heliospheric Imager observations for tomographic reconstruction of interplanetary CMEs</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Barnes, D. 2017-12-01 The multiple, spatially separated vantage points afforded by the STEREO and SOHO missions provide physicists with a means to infer the three-dimensional structure of the solar corona via tomographic imaging. The reconstruction process combines these multiple projections of the optically thin plasma to constrain its three-dimensional density structure and has been successfully applied to the low corona using the STEREO and SOHO coronagraphs. However, the technique is also possible at larger, inter-planetary distances using wide-angle imagers, such as the STEREO Heliospheric Imagers (HIs), to observe faint solar wind plasma and Coronal Mass Ejections (CMEs). Limited small-scale structure may be inferred from only three, or fewer, viewpoints and the work presented here is done so with the aim of establishing techniques for observing CMEs with upcoming and future HI-like technology. We use simulated solar wind densities to compute realistic white-light HI observations, with which we explore the requirements of such instruments for determining solar wind plasma density structure via tomography. We exploit this information to investigate the optimal orbital characteristics, such as spacecraft number, separation, inclination and eccentricity, necessary to perform the technique with HIs. Further to this we argue that tomography may be greatly enhanced by means of improved instrumentation; specifically, the use of wide-angle imagers capable of measuring polarised light. This work has obvious space weather applications, serving as a demonstration for potential future missions (such as at L1 and L5) and will prove timely in fully exploiting the science return from the upcoming Solar Orbiter and Parker Solar Probe missions. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active">17</li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active">18</li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910016676','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910016676">HUT observations of carbon monoxide in the coma of Comet Levy (1990c)</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Feldman, P. D.; Davidsen, A. F.; Blair, W. P.; Bowers, C. W.; Dixon, W. V.; Durrance, S. T.; Henry, R. C.; Kriss, G. A.; Kruk, J.; Moos, H. W. 1991-01-01 Observations of comet Levy (1990c) were made with the Hopkins Ultraviolet Telescope during the Astro-1 Space Shuttle mission on 10 Dec. 1990. The spectrum, covering the wavelength range 415 to 1850 A at a spectral emission of 3 A (in first order), shows the presence of carbon monoxide and atomic hydrogen, carbon, and sulfur in the coma. Aside from H I Lyman-beta, no cometary features are detected below 1200 A, although cometary O I and O II would be masked by the same emissions present in the day airglow spectrum. The 9.4 x 116 arcsec aperture corresponds to 12,000 x 148,000 km at the comet. The derived production rate of CO relative to water, 0.13 + or - 0.02, compared with the same ratio derived from IUE observations (made in Sep. 1990) which sample a much smaller region of the coma, 0.04 + or - 0.01, suggests the presence of an extended source of CO, as was found in comet Halley. Upper limits on Ne and Ar abundance are within an order of magnitude or solar abundances. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss028e029679.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss028e029679.html">Earth observation taken by the Expedition 28 crew</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-08-21 ISS028-E-029679 (21 Aug. 2011) --- A night time view of India-Pakistan borderlands is featured in this image photographed by an Expedition 28 crew member on the International Space Station. Clusters of yellow lights on the Indo-Gangetic Plain of northern India and northern Pakistan reveal numerous cities both large and small in this photograph. Of the hundreds of clusters, the largest are the metropolitan areas associated with the capital cities of Islamabad, Pakistan in the foreground and New Delhi, India at the top?for scale these metropolitan areas are approximately 700 kilometers apart. The lines of major highways connecting the larger cities also stand out. More subtle but still visible at night are the general outlines of the towering and partly cloud-covered Himalayan ranges immediately to the north (left). A striking feature of this photograph is the line of lights, with a distinctly more orange hue, snaking across the central part of the image. It appears to be more continuous and brighter than most highways in the view. This is the fenced and floodlit border zone between the countries of India and Pakistan. The fence is designed to discourage smuggling and arms trafficking between the two countries. A similar fenced zone separates India?s eastern border from Bangladesh (not visible). This image was taken with a 16-mm lens, which provides the wide field of view, as the space station was tracking towards the southeast across the subcontinent of India. The station crew took the image as part of a continuous series of frames, each frame taken with a one-second exposure time to maximize light collection ? unfortunately, this also causes blurring of some ground features. The distinct, bright zone above the horizon (visible at top) is produced by airglow, a phenomena caused by excitation of atoms and molecules high in the atmosphere (above 80 kilometers, or 50 miles altitude) by ultraviolet radiation from the sun. Part of the ISS Permanent Multipurpose Module </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140001025','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140001025">Interactions between Coronal Mass Ejections Viewed in Coordinated Imaging and In Situ Observations</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Liu, Ying D.; Luhmann, Janet G.; Moestl, Christian; Martinez-Oliveros, Juan C.; Bale, Stewart D.; Lin, Robert P.; Harrison, Richard A.; Temmer, Manuela; Webb, David F.; Odstrcil, Dusan 2013-01-01 The successive coronal mass ejections (CMEs) from 2010 July 30 - August 1 present us the first opportunity to study CME-CME interactions with unprecedented heliospheric imaging and in situ observations from multiple vantage points. We describe two cases of CME interactions: merging of two CMEs launched close in time and overtaking of a preceding CME by a shock wave. The first two CMEs on August 1 interact close to the Sun and form a merged front, which then overtakes the July 30 CME near 1 AU, as revealed by wide-angle imaging observations. Connections between imaging observations and in situ signatures at 1 AU suggest that the merged front is a shock wave, followed by two ejecta observed at Wind which seem to have already merged. In situ measurements show that the CME from July 30 is being overtaken by the shock at 1 AU and is significantly compressed, accelerated and heated. The interaction between the preceding ejecta and shock also results in variations in the shock strength and structure on a global scale, as shown by widely separated in situ measurements from Wind and STEREO B. These results indicate important implications of CME-CME interactions for shock propagation, particle acceleration and space weather forecasting. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860012558&hterms=barium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dbarium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860012558&hterms=barium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dbarium">Observations of barium ion jets in the magnetosphere using Doppler imaging systems and very sensitive imaging systems using imaging photon detectors</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Rees, D.; Conboy, J.; Heinz, W.; Heppner, J. P. 1985-01-01 Observations of four shaped charge releases from rockets launched from Alaska are described. Results demonstrate that imaging and Doppler imaging instruments, based on exploiting the imaging photon detector, provide additional insight into the motion and development of low intensity targets such as the fast ion jets produced by shaped charge releases. It is possible to trace the motion of fast ion jets to very great distances, of the order of 50,000 km, outward along the Earth's magnetic field, when the conditions are suitable for the outward (upward) motion and/or acceleration of such ion jets. It is shown that ion jets, which fade below the lower sensitivity threshold of previous instruments, do not always disappear. There is no evidence of an abrupt field-aligned shear-type acceleration. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23878358','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23878358">Diffusion-weighted magnetic resonance imaging combined with T2-weighted images in the detection of small breast cancer: a single-center multi-observer study.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Wu, Lian-Ming; Chen, Jie; Hu, Jiani; Gu, Hai-Yan; Xu, Jian-Rong; Hua, Jia 2014-02-01 Breast cancer is the most common cancer in women worldwide. However, it remains a difficult diagnosis problem to differentiate between benign and malignant breast lesions, especially in small early breast lesions. To assess the diagnostic value of diffusion-weighted imaging (DWI) combined with T2-weighted imaging (T2WI) for small breast cancer characterization. Fifty-eight patients (65 lesions) with a lesion <2 cm in diameter underwent 3.0 Tesla breast magnetic resonance imaging (MRI) including DWI and histological analysis. Three observers with varying experience levels reviewed MRI. The probability of breast cancer in each lesion on MR images was recorded with a 5-point scale. Areas under the receiver-operating characteristic curve (AUCs) were compared by using the Z test; sensitivity and specificity were determined with the Z test after adjusting for data clustering. AUC of T2WI and DWI (Observer 1, 0.95; Observer 2, 0.91; Observer 3, 0.83) was greater than that of T2WI (Observer 1, 0.80; Observer 2, 0.74; Observer 3, 0.70) for all observers (P < 0.0001 in all comparisons). Sensitivity of T2WI and DWI (Observer 1, 90%; Observer 2, 93%; and Observer 3, 86%) was greater than that of T2WI alone (Observer 1, 76%; Observer 2, 83%; Observer 3, 79%) for all observers (P < 0.0001 in all comparisons). Specificity of T2WI and DWI was greater than that of T2WI alone for observer 1 (89% vs. 72%, P < 0.01) and observer 2 (94% vs. 78%, P < 0.001). DWI combined with T2WI can improve the diagnostic performance of MRI in small breast cancer characterization. It should be considered selectively in the preoperative evaluation of patients with small lesions of the breast. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950029592&hterms=twilight&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950029592&hterms=twilight&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dtwilight">Simultaneous retrieval of the solar EUV flux and neutral thermospheric O, O2, N2, and temperature from twilight airglow</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Fennelly, J. A.; Torr, D. G.; Richards, P. G.; Torr, M. R. 1994-01-01 We present a method to retrieve neutral thermospheric composition and the solar EUV flux from ground-based twilight optical measurements of the O(+) ((exp 2)P) 7320 A and O((exp 1)D) 6300 A airglow emissions. The parameters retrieved are the neutral temperature, the O, O2, N2 density profiles, and a scaling factor for the solar EUV flux spectrum. The temperature, solar EUV flux scaling factor, and atomic oxygen density are first retrieved from the 7320-A emission, which are then used with the 6300-A emission to retrieve the O2 and N2 densities. The retrieval techniques have been verified by computer simulations. We have shown that the retrieval technique is able to statistically retrieve values, between 200 and 400 km, within an average error of 3.1 + or - 0.6% for thermospheric temperature, 3.3 + or - 2.0% for atomic oxygen, 2.3 + or - 1.3% for molecular oxygen, and 2.4 + or - 1.3% for molecular nitrogen. The solar EUV flux scaling factor was found to have a retrieval error of 5.1 + or - 2.3%. All the above errors have a confidence level of 95%. The purpose of this paper is to prove the viability and usefulness of the retrieval technique by demonstrating the ability to retrieve known quantities under a realistic simulation of the measurement process, excluding systematic effects. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6515E..19L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6515E..19L">Combining a wavelet transform with a channelized Hotelling observer for tumor detection in 3D PET oncology imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lartizien, Carole; Tomei, Sandrine; Maxim, Voichita; Odet, Christophe 2007-03-01 This study evaluates new observer models for 3D whole-body Positron Emission Tomography (PET) imaging based on a wavelet sub-band decomposition and compares them with the classical constant-Q CHO model. Our final goal is to develop an original method that performs guided detection of abnormal activity foci in PET oncology imaging based on these new observer models. This computer-aided diagnostic method would highly benefit to clinicians for diagnostic purpose and to biologists for massive screening of rodents populations in molecular imaging. Method: We have previously shown good correlation of the channelized Hotelling observer (CHO) using a constant-Q model with human observer performance for 3D PET oncology imaging. We propose an alternate method based on combining a CHO observer with a wavelet sub-band decomposition of the image and we compare it to the standard CHO implementation. This method performs an undecimated transform using a biorthogonal B-spline 4/4 wavelet basis to extract the features set for input to the Hotelling observer. This work is based on simulated 3D PET images of an extended MCAT phantom with randomly located lesions. We compare three evaluation criteria: classification performance using the signal-to-noise ratio (SNR), computation efficiency and visual quality of the derived 3D maps of the decision variable λ. The SNR is estimated on a series of test images for a variable number of training images for both observers. Results: Results show that the maximum SNR is higher with the constant-Q CHO observer, especially for targets located in the liver, and that it is reached with a smaller number of training images. However, preliminary analysis indicates that the visual quality of the 3D maps of the decision variable λ is higher with the wavelet-based CHO and the computation time to derive a 3D λ-map is about 350 times shorter than for the standard CHO. This suggests that the wavelet-CHO observer is a good candidate for use in our guided </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H11E1222F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H11E1222F">Riverine Bathymetry Imaging with Indirect Observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Farthing, M.; Lee, J. H.; Ghorbanidehno, H.; Hesser, T.; Darve, E. F.; Kitanidis, P. K. 2017-12-01 Bathymetry, i.e, depth, imaging in a river is of crucial importance for shipping operations and flood management. With advancements in sensor technology and computational resources, various types of indirect measurements can be used to estimate high-resolution riverbed topography. Especially, the use of surface velocity measurements has been actively investigated recently since they are easy to acquire at a low cost in all river conditions and surface velocities are sensitive to the river depth. In this work, we image riverbed topography using depth-averaged quasi-steady velocity observations related to the topography through the 2D shallow water equations (SWE). The principle component geostatistical approach (PCGA), a fast and scalable variational inverse modeling method powered by low-rank representation of covariance matrix structure, is presented and applied to two "twin" riverine bathymetry identification problems. To compare the efficiency and effectiveness of the proposed method, an ensemble-based approach is also applied to the test problems. Results demonstrate that PCGA is superior to the ensemble-based approach in terms of computational effort and accuracy. Especially, the results obtained from PCGA capture small-scale bathymetry features irrespective of the initial guess through the successive linearization of the forward model. Analysis on the direct survey data of the riverine bathymetry used in one of the test problems shows an efficient, parsimonious choice of the solution basis in PCGA so that the number of the numerical model runs used to achieve the inversion results is close to the minimum number that reconstructs the underlying bathymetry. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ApJ...849...10F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ApJ...849...10F">A Compressed Sensing-based Image Reconstruction Algorithm for Solar Flare X-Ray Observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Felix, Simon; Bolzern, Roman; Battaglia, Marina 2017-11-01 One way of imaging X-ray emission from solar flares is to measure Fourier components of the spatial X-ray source distribution. We present a new compressed sensing-based algorithm named VIS_CS, which reconstructs the spatial distribution from such Fourier components. We demonstrate the application of the algorithm on synthetic and observed solar flare X-ray data from the Reuven Ramaty High Energy Solar Spectroscopic Imager satellite and compare its performance with existing algorithms. VIS_CS produces competitive results with accurate photometry and morphology, without requiring any algorithm- and X-ray-source-specific parameter tuning. Its robustness and performance make this algorithm ideally suited for the generation of quicklook images or large image cubes without user intervention, such as for imaging spectroscopy analysis. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940031102','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940031102">Obtaining coincident image observations for Mission to Planet Earth science data return</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Newman, Lauri Kraft; Folta, David C.; Farrell, James P. 1994-01-01 One objective of the Mission to Planet Earth (MTPE) program involves comparing data from various instruments on multiple spacecraft to obtain a total picture of the Earth's systems. To correlate image data from instruments on different spacecraft, these spacecraft must be able to image the same location on the Earth at approximately the same time. Depending on the orbits of the spacecraft involved, complicated operational details must be considered to obtain such observations. If the spacecraft are in similar orbits, close formation flying or synchronization techniques may be used to assure coincident observations. If the orbits are dissimilar, the launch time of the second satellite may need to be restricted in order to align its orbit with that of the first satellite launched. This paper examines strategies for obtaining coincident observations for spacecraft in both similar and dissimilar orbits. Although these calculations may be performed easily for coplanar spacecraft, the non-coplanar case involves additional considerations which are incorporated into the algorithms presented herein. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22482368-computational-human-observer-image-quality-evaluation-low-dose-knowledge-based-ct-iterative-reconstruction','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22482368-computational-human-observer-image-quality-evaluation-low-dose-knowledge-based-ct-iterative-reconstruction">Computational and human observer image quality evaluation of low dose, knowledge-based CT iterative reconstruction</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Eck, Brendan L.; Fahmi, Rachid; Miao, Jun 2015-10-15 Purpose: Aims in this study are to (1) develop a computational model observer which reliably tracks the detectability of human observers in low dose computed tomography (CT) images reconstructed with knowledge-based iterative reconstruction (IMR™, Philips Healthcare) and filtered back projection (FBP) across a range of independent variables, (2) use the model to evaluate detectability trends across reconstructions and make predictions of human observer detectability, and (3) perform human observer studies based on model predictions to demonstrate applications of the model in CT imaging. Methods: Detectability (d′) was evaluated in phantom studies across a range of conditions. Images were generated usingmore » a numerical CT simulator. Trained observers performed 4-alternative forced choice (4-AFC) experiments across dose (1.3, 2.7, 4.0 mGy), pin size (4, 6, 8 mm), contrast (0.3%, 0.5%, 1.0%), and reconstruction (FBP, IMR), at fixed display window. A five-channel Laguerre–Gauss channelized Hotelling observer (CHO) was developed with internal noise added to the decision variable and/or to channel outputs, creating six different internal noise models. Semianalytic internal noise computation was tested against Monte Carlo and used to accelerate internal noise parameter optimization. Model parameters were estimated from all experiments at once using maximum likelihood on the probability correct, P{sub C}. Akaike information criterion (AIC) was used to compare models of different orders. The best model was selected according to AIC and used to predict detectability in blended FBP-IMR images, analyze trends in IMR detectability improvements, and predict dose savings with IMR. Predicted dose savings were compared against 4-AFC study results using physical CT phantom images. Results: Detection in IMR was greater than FBP in all tested conditions. The CHO with internal noise proportional to channel output standard deviations, Model-k4, showed the best trade </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010020056&hterms=Mason&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D30%26Ntt%3DS%2BJ%2BMason','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010020056&hterms=Mason&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D30%26Ntt%3DS%2BJ%2BMason">First Intrinsic Anisotropy Observations With the Cosmic Background Imager</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Padin, S.; Cartwright, J. K.; Mason, B. S.; Pearson, T. J.; Readhead, A. C. S.; Shepherd, M. C.; Sievers, J.; Udomprasert, P. S.; Holzapfel, W. L.; Myers, S. T.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20010020056'); toggleEditAbsImage('author_20010020056_show'); toggleEditAbsImage('author_20010020056_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20010020056_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20010020056_hide"> 2001-01-01 We present the first results of observations of the intrinsic anisotropy of the cosmic microwave background radiation with the Cosmic Background Imager from a site at 5080 in altitude in northern Chile. Our observations show a sharp decrease in C_l in the range l = 400 - 1500. Such a decrease in power at high l is one of the fundamental predictions of the standard cosmological model, and these are the first observations which cover a broad enough 1-range to show this decrease in a single experiment. The power, C_l, at l approximately 600 is higher than measured by Boomerang and Maxima, with the differences being significant at the 2.7sigma and 1.9sigma levels, respectively. The C_l we have measured enable us to place limits on the density parameter, Omega(tot) <= 0.4 or Omega(tot) >= 0.7 (90% confidence). </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810025174','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810025174">Large storms: Airglow and related measurements. VLF observations, volume 4</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1981-01-01 The data presented show the typical values and range of ionospheric and magnetospheric characteristics, as viewed from 1400 km with the ISIS 2 instruments. The definition of each data set depends partly on geophysical parameters and partly on satellite operating mode. Preceding the data set is a description of the organizational parameters and a review of the objectives and general characteristics of the data set. The data are shown as a selection from 12 different data formats. Each data set has a different selection of formats, but uniformity of a given format selection is preserved throughout each data set. Each data set consists of a selected number of passes, each comprising a format combination that is most appropriae for the particular data set. Description of ISIS 2 instruments are provided. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016amos.confE..26S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016amos.confE..26S">Automated Astrometric Analysis of Satellite Observations using Wide-field Imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Skuljan, J.; Kay, J. 2016-09-01 An observational trial was conducted in the South Island of New Zealand from 24 to 28 February 2015, as a collaborative effort between the United Kingdom and New Zealand in the area of space situational awareness. The aim of the trial was to observe a number of satellites in low Earth orbit using wide-field imaging from two separate locations, in order to determine the space trajectory and compare the measurements with the predictions based on the standard two-line elements. This activity was an initial step in building a space situational awareness capability at the Defence Technology Agency of the New Zealand Defence Force. New Zealand has an important strategic position as the last land mass that many satellites selected for deorbiting pass before entering the Earth's atmosphere over the dedicated disposal area in the South Pacific. A preliminary analysis of the trial data has demonstrated that relatively inexpensive equipment can be used to successfully detect satellites at moderate altitudes. A total of 60 satellite passes were observed over the five nights of observation and about 2600 images were collected. A combination of cooled CCD and standard DSLR cameras were used, with a selection of lenses between 17 mm and 50 mm in focal length, covering a relatively wide field of view of 25 to 60 degrees. The CCD cameras were equipped with custom-made GPS modules to record the time of exposure with a high accuracy of one millisecond, or better. Specialised software has been developed for automated astrometric analysis of the trial data. The astrometric solution is obtained as a two-dimensional least-squares polynomial fit to the measured pixel positions of a large number of stars (typically 1000) detected across the image. The star identification is fully automated and works well for all camera-lens combinations used in the trial. A moderate polynomial degree of 3 to 5 is selected to take into account any image distortions introduced by the lens. A typical RMS </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.473.1038P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.473.1038P">Robust sparse image reconstruction of radio interferometric observations with PURIFY</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Pratley, Luke; McEwen, Jason D.; d'Avezac, Mayeul; Carrillo, Rafael E.; Onose, Alexandru; Wiaux, Yves 2018-01-01 Next-generation radio interferometers, such as the Square Kilometre Array, will revolutionize our understanding of the Universe through their unprecedented sensitivity and resolution. However, to realize these goals significant challenges in image and data processing need to be overcome. The standard methods in radio interferometry for reconstructing images, such as CLEAN, have served the community well over the last few decades and have survived largely because they are pragmatic. However, they produce reconstructed interferometric images that are limited in quality and scalability for big data. In this work, we apply and evaluate alternative interferometric reconstruction methods that make use of state-of-the-art sparse image reconstruction algorithms motivated by compressive sensing, which have been implemented in the PURIFY software package. In particular, we implement and apply the proximal alternating direction method of multipliers algorithm presented in a recent article. First, we assess the impact of the interpolation kernel used to perform gridding and degridding on sparse image reconstruction. We find that the Kaiser-Bessel interpolation kernel performs as well as prolate spheroidal wave functions while providing a computational saving and an analytic form. Secondly, we apply PURIFY to real interferometric observations from the Very Large Array and the Australia Telescope Compact Array and find that images recovered by PURIFY are of higher quality than those recovered by CLEAN. Thirdly, we discuss how PURIFY reconstructions exhibit additional advantages over those recovered by CLEAN. The latest version of PURIFY, with developments presented in this work, is made publicly available. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DPS....4521103S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DPS....4521103S">Deriving Atmospheric Properties and Escape Rates from MAVEN's Imaging UV Spectrograph (IUVS)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Schneider, Nicholas M.; IUVS Science Team 2013-10-01 MAVEN (Mars Volatile and Atmosphere EvolutioN) is a Mars Scout mission being readied for launch in November 2013. The key hardware and management partners are University of Colorado, Goddard Space Flight Center, University of California at Berkeley, Lockheed Martin, and the Jet Propulsion Laboratory. MAVEN carries a powerful suite of fields and particles instruments and a sophisticated remote sensing instrument, the Imaging UltraViolet Spectrograph (IUVS). This presentation begins by describing IUVS' science goals, instrument design, operational approach and data analysis strategy. IUVS supports the top-level MAVEN science goals: measure the present state of the atmosphere, observe its response to varying solar stimuli, and use the information to estimate loss from Mars' atmosphere over time. The instrument operates at low spectral resolution spanning the FUV and MUV ranges in separate channels, and at high resolution around the hydrogen Lyman alpha line to measure the D/H ratio in the upper atmosphere. MAVEN carries the instrument on an Articulated Payload Platform which orients the instrument for optimal observations during four segments of its 4.5 hr elliptical orbit. During periapse passage, IUVS uses a scan mirror to obtain vertical profiles of emissions from the atmosphere and ionosphere. Around apoapse, the instrument builds up low-resolution images of the atmosphere at multiple wavelengths. In between, the instrument measures emissions from oxygen, hydrogen and deuterium in the corona. IUVS also undertakes day-long stellar occultation campaigns at 2 month intervals, to measure the state of the atmosphere at altitudes below the airglow layer and in situ sampling. All data will be pipeline-processed from line brightnesses to column abundances, local densities and global 3-D maps. The focus of the presentation is development of these automatic processing algorithms and the data products they will provide to the Mars community through the PDS Atmospheres Node </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss016e015496.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss016e015496.html">View of Solar Array Panels taken during Expedition 16</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2007-12-09 ISS016-E-015496 (9 Dec. 2007) --- Solar array panels of the International Space Station are featured in this image photographed by an Expedition 16 crewmember (out of frame) from a window on the station. The blackness of space and airglow of Earth's horizon provide the backdrop for the scene. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020049425&hterms=Galileo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DGalileo','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020049425&hterms=Galileo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DGalileo">Monte Carlo Radiative Transfer Modeling of Lightning Observed in Galileo Images of Jupiter</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Dyudine, U. A.; Ingersoll, Andrew P. 2002-01-01 We study lightning on Jupiter and the clouds illuminated by the lightning using images taken by the Galileo orbiter. The Galileo images have a resolution of 25 km/pixel and axe able to resolve the shape of the single lightning spots in the images, which have full widths at half the maximum intensity in the range of 90-160 km. We compare the measured lightning flash images with simulated images produced by our ED Monte Carlo light-scattering model. The model calculates Monte Carlo scattering of photons in a ED opacity distribution. During each scattering event, light is partially absorbed. The new direction of the photon after scattering is chosen according to a Henyey-Greenstein phase function. An image from each direction is produced by accumulating photons emerging from the cloud in a small range (bins) of emission angles. Lightning bolts are modeled either as points or vertical lines. Our results suggest that some of the observed scattering patterns axe produced in a 3-D cloud rather than in a plane-parallel cloud layer. Lightning is estimated to occur at least as deep as the bottom of the expected water cloud. For the six cases studied, we find that the clouds above the lightning are optically thick (tau > 5). Jovian flashes are more regular and circular than the largest terrestrial flashes observed from space. On Jupiter there is nothing equivalent to the 30-40-km horizontal flashes which axe seen on Earth. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4710508R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4710508R">Pluto's Extended Atmosphere: New Horizons Alice Lyman-α Imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Retherford, Kurt D.; Gladstone, G. Randall; Stern, S. Alan; Weaver, Harold A.; Young, Leslie A.; Ennico, Kimberly A.; Olkin, Cathy B.; Cheng, Andy F.; Greathouse, Thomas K.; Hinson, David P.; Kammer, Joshua A.; Linscott, Ivan R.; Parker, Alex H.; Parker, Joel Wm.; Pryor, Wayne R.; Schindhelm, Eric; Singer, Kelsi N.; Steffl, Andrew J.; Strobel, Darrell F.; Summers, Michael E.; Tsang, Constantine C. C.; Tyler, G. Len; Versteeg, Maarten H.; Woods, William W.; Cunningham, Nathaniel J.; Curdt, Werner 2015-11-01 Pluto's upper atmosphere is expected to extend several planetary radii, proportionally more so than for any planet in our solar system. Atomic hydrogen is readily produced at lower altitudes due to photolysis of methane and transported upward to become an important constituent. The Interplanetary Medium (IPM) provides a natural light source with which to study Pluto's atomic hydrogen atmosphere. While direct solar Lyman-α emissions dominate the signal at 121.6 nm at classical solar system distances, the contribution of diffuse illumination by IPM Lyman-α sky-glow is roughly on par at Pluto (Gladstone et al., Icarus, 2015). Hydrogen atoms in Pluto's upper atmosphere scatter these bright Lyα emission lines, and detailed simulations of the radiative transfer for these photons indicate that Pluto would appear dark against the IPM Lyα background. The Pluto-Alice UV imaging spectrograph on New Horizons conducted several observations of Pluto during the encounter to search for airglow emissions, characterize its UV reflectance spectra, and to measure the radial distribution of IPM Lyα near the disk. Our early results suggest that these model predictions for the darkening of IPM Lyα with decreasing altitude being measureable by Pluto-Alice were correct. We'll report our progress toward extracting H and CH4 density profiles in Pluto's upper atmosphere through comparisons of these data with detailed radiative transfer modeling. These New Horizons findings will have important implications for determining the extent of Pluto's atmosphere and related constraints to high-altitude vertical temperature structure and atmospheric escape.This work was supported by NASA's New Horizons project. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20076181','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20076181">NASA Program of Airborne Optical Observations.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Bader, M; Wagoner, C B 1970-02-01 NASA's Ames Research Center currently operates a Convair 990 four-engine jet transport as a National Facility for airborne scientific research (astronomy, aurora, airglow, meteorology, earth resources). This aircraft can carry about twelve experiments to 12 km for several hours. A second aircraft, a twin-engine Lear Jet, has been used on a limited basis for airborne science and can carry one experiment to 15 km for 1 h. Mobility and altitude are the principal advantages over ground sites, while large payload and personnel carrying capabilities, combined with ease of operations and relatively low cost, are the main advantages compared to balloons, rockets, or satellites. Typical airborne instrumentation and scientific results are presented. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active">18</li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active">19</li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JPhCS.969a2153M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JPhCS.969a2153M">Observation of ferroelastic domains in layered magnetic compounds using birefringence imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Miura, Yoko; Okumura, Kazuya; Manaka, Hirotaka 2018-03-01 The two-dimensional Heisenberg antiferromagnet (C2H5NH3)2CuCl4 is a candidate compound for the coexistence of ferroelectricity and ferroelasticity; however, the microscopic observations of multiferroic domains may still be unclear. In-plane birefringence imaging measurements were performed to observe the manner in which the ferroelectric and the ferroelastic domains change during phase transitions between 15 K and 300 K. It was found that 90° ferroelastic domains appeared in the ab-plane at 300 K. As the temperature decreased toward 15 K, each domain inverted at a certain temperature (T a) without structural or magnetic phase transitions. The value of T a was found to be significantly influenced by external stresses; therefore, birefringence imaging techniques are useful for investigating variations in ferroelastic domains with temperature. Furthermore, a structural phase transition from orthorhombic to monoclinic or triclinic occurred at 230 ~ 240 K; however, no spontaneous polarization appeared in the ab-plane over the entire investigated range. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22679727-compressed-sensing-based-image-reconstruction-algorithm-solar-flare-ray-observations','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22679727-compressed-sensing-based-image-reconstruction-algorithm-solar-flare-ray-observations">A Compressed Sensing-based Image Reconstruction Algorithm for Solar Flare X-Ray Observations</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Felix, Simon; Bolzern, Roman; Battaglia, Marina, E-mail: simon.felix@fhnw.ch, E-mail: roman.bolzern@fhnw.ch, E-mail: marina.battaglia@fhnw.ch One way of imaging X-ray emission from solar flares is to measure Fourier components of the spatial X-ray source distribution. We present a new compressed sensing-based algorithm named VIS-CS, which reconstructs the spatial distribution from such Fourier components. We demonstrate the application of the algorithm on synthetic and observed solar flare X-ray data from the Reuven Ramaty High Energy Solar Spectroscopic Imager satellite and compare its performance with existing algorithms. VIS-CS produces competitive results with accurate photometry and morphology, without requiring any algorithm- and X-ray-source-specific parameter tuning. Its robustness and performance make this algorithm ideally suited for the generation ofmore » quicklook images or large image cubes without user intervention, such as for imaging spectroscopy analysis.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140002252','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140002252">Images of Bottomside Irregularities Observed at Topside Altitudes</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Burke, William J.; Gentile, Louise C.; Shomo, Shannon R.; Roddy, Patrick A.; Pfaff, Robert F. 2012-01-01 We analyzed plasma and field measurements acquired by the Communication/ Navigation Outage Forecasting System (C/NOFS) satellite during an eight-hour period on 13-14 January 2010 when strong to moderate 250 MHz scintillation activity was observed at nearby Scintillation Network Decision Aid (SCINDA) ground stations. C/NOFS consistently detected relatively small-scale density and electric field irregularities embedded within large-scale (approx 100 km) structures at topside altitudes. Significant spectral power measured at the Fresnel (approx 1 km) scale size suggests that C/NOFS was magnetically conjugate to bottomside irregularities similar to those directly responsible for the observed scintillations. Simultaneous ion drift and plasma density measurements indicate three distinct types of large-scale irregularities: (1) upward moving depletions, (2) downward moving depletions, and (3) upward moving density enhancements. The first type has the characteristics of equatorial plasma bubbles; the second and third do not. The data suggest that both downward moving depletions and upward moving density enhancements and the embedded small-scale irregularities may be regarded as Alfvenic images of bottomside irregularities. This interpretation is consistent with predictions of previously reported theoretical modeling and with satellite observations of upward-directed Poynting flux in the low-latitude ionosphere. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-STS099-349-002.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-STS099-349-002.html">Views of a sunrise and an aurora taken from OV-105 during STS-99</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2000-04-06 STS099-349-002 (11-22 February 2000) ---The Space Shuttle Endeavour's vertical stabilizer is visible in the foreground of this 35mm frame featuring airglow, the thin greenish band above the horizon. Airglow is radiation emitted by the atmosphere from a layer about 30 kilometers thick and about 100 kilometers altitude. The predominant emission in airglow is the green 5577-Angstrom wavelength emission from atomic oxygen atoms. Airglow is always and everywhere present in the atmosphere; it results from the recombination of molecules that have been broken apart by solar radiation during the day. But airglow is so faint that it can only be seen at night by looking "edge on" at the emission layer, such as the view astronauts have in orbit. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JaJAP..53dEL02T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JaJAP..53dEL02T">A CMOS image sensor with stacked photodiodes for lensless observation system of digital enzyme-linked immunosorbent assay</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Takehara, Hironari; Miyazawa, Kazuya; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Kim, Soo Hyeon; Iino, Ryota; Noji, Hiroyuki; Ohta, Jun 2014-01-01 A CMOS image sensor with stacked photodiodes was fabricated using 0.18 µm mixed signal CMOS process technology. Two photodiodes were stacked at the same position of each pixel of the CMOS image sensor. The stacked photodiodes consist of shallow high-concentration N-type layer (N+), P-type well (PW), deep N-type well (DNW), and P-type substrate (P-sub). PW and P-sub were shorted to ground. By monitoring the voltage of N+ and DNW individually, we can observe two monochromatic colors simultaneously without using any color filters. The CMOS image sensor is suitable for fluorescence imaging, especially contact imaging such as a lensless observation system of digital enzyme-linked immunosorbent assay (ELISA). Since the fluorescence increases with time in digital ELISA, it is possible to observe fluorescence accurately by calculating the difference from the initial relation between the pixel values for both photodiodes. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22634775-su-computer-simulation-model-observer-task-based-image-quality-assessment-radiation-therapy','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22634775-su-computer-simulation-model-observer-task-based-image-quality-assessment-radiation-therapy">SU-F-J-178: A Computer Simulation Model Observer for Task-Based Image Quality Assessment in Radiation Therapy</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Dolly, S; Mutic, S; Anastasio, M Purpose: Traditionally, image quality in radiation therapy is assessed subjectively or by utilizing physically-based metrics. Some model observers exist for task-based medical image quality assessment, but almost exclusively for diagnostic imaging tasks. As opposed to disease diagnosis, the task for image observers in radiation therapy is to utilize the available images to design and deliver a radiation dose which maximizes patient disease control while minimizing normal tissue damage. The purpose of this study was to design and implement a new computer simulation model observer to enable task-based image quality assessment in radiation therapy. Methods: A modular computer simulation framework wasmore » developed to resemble the radiotherapy observer by simulating an end-to-end radiation therapy treatment. Given images and the ground-truth organ boundaries from a numerical phantom as inputs, the framework simulates an external beam radiation therapy treatment and quantifies patient treatment outcomes using the previously defined therapeutic operating characteristic (TOC) curve. As a preliminary demonstration, TOC curves were calculated for various CT acquisition and reconstruction parameters, with the goal of assessing and optimizing simulation CT image quality for radiation therapy. Sources of randomness and bias within the system were analyzed. Results: The relationship between CT imaging dose and patient treatment outcome was objectively quantified in terms of a singular value, the area under the TOC (AUTOC) curve. The AUTOC decreases more rapidly for low-dose imaging protocols. AUTOC variation introduced by the dose optimization algorithm was approximately 0.02%, at the 95% confidence interval. Conclusion: A model observer has been developed and implemented to assess image quality based on radiation therapy treatment efficacy. It enables objective determination of appropriate imaging parameter values (e.g. imaging dose). Framework flexibility allows for </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020083315','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020083315">Earth Observation Services (Image Processing Software)</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1992-01-01 San Diego State University and Environmental Systems Research Institute, with other agencies, have applied satellite imaging and image processing techniques to geographic information systems (GIS) updating. The resulting images display land use and are used by a regional planning agency for applications like mapping vegetation distribution and preserving wildlife habitats. The EOCAP program provides government co-funding to encourage private investment in, and to broaden the use of NASA-developed technology for analyzing information about Earth and ocean resources. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA198889','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA198889">Dynamics of the Polar Mesopause and Lower Thermosphere Region as Observed in the Night Airglow Emissions</a> <a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a> 1988-02-01 feasible. However, only the winter 80-110 km region could be studied by this approach, due to the limitation in the observing method , i.e. nightglow...epoch methods have been employed. The diurnal tide component at the mesopause, that according to the latest tidal models should dominate in polar region...temperature was calculated by Kvifte’s method . tweem temperature and intensity was found by Shaqae [1974] using the intensity ratio of the P,(2) and P,(3 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16134866','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16134866">Dependence of reconstructed image characteristics on the observation condition in light-in-flight recording by holography.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Komatsu, Aya; Awatsuji, Yasuhiro; Kubota, Toshihiro 2005-08-01 We analyze the dependence of the reconstructed image characteristic on the observation condition in the light-in-flight recording by holography both theoretically and experimentally. This holography makes it possible to record a propagating light pulse. We have found that the shape of the reconstructed image is changed when the observation position is vertically moved along the hologram plane. The reconstructed image is numerically simulated on the basis of the theory and is experimentally obtained by using a 373 fs pulsed laser. The numerical results agree with the experimental result, and the validity of the theory is verified. Also, experimental results are analyzed and the restoration of the reconstructed image is discussed. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...574A.120J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...574A.120J">High-contrast imaging with Spitzer: deep observations of Vega, Fomalhaut, and ɛ Eridani</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Janson, Markus; Quanz, Sascha P.; Carson, Joseph C.; Thalmann, Christian; Lafrenière, David; Amara, Adam 2015-02-01 Stars with debris disks are intriguing targets for direct-imaging exoplanet searches, owing both to previous detections of wide planets in debris disk systems, and to commonly existing morphological features in the disks themselves that may be indicative of a planetary influence. Here we present observations of three of the most nearby young stars, which are also known to host massive debris disks: Vega, Fomalhaut, and ɛ Eri. The Spitzer Space Telescope is used at a range of orientation angles for each star to supply a deep contrast through angular differential imaging combined with high-contrast algorithms. The observations provide the opportunity to probe substantially colder bound planets (120-330 K) than is possible with any other technique or instrument. For Vega, some apparently very red candidate point sources detected in the 4.5 μm image remain to be tested for common proper motion. The images are sensitive to ~2 Mjup companions at 150 AU in this system. The observations presented here represent the first search for planets around Vega using Spitzer. The upper 4.5 μm flux limit on Fomalhaut b could be further constrained relative to previous data. In the case of ɛ Eri, planets below both the effective temperature and the mass of Jupiter could be probed from 80 AU and outward, although no such planets were found. The data sensitively probe the regions around the edges of the debris rings in the systems where planets can be expected to reside. These observations validate previous results showing that more than an order of magnitude improvement in performance in the contrast-limited regime can be acquired with respect to conventional methods by applying sophisticated high-contrast techniques to space-based telescopes, thanks to the high degree of PSF stability provided in this environment. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28134567','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28134567">Blurred digital mammography images: an analysis of technical recall and observer detection performance.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Ma, Wang Kei; Borgen, Rita; Kelly, Judith; Millington, Sara; Hilton, Beverley; Aspin, Rob; Lança, Carla; Hogg, Peter 2017-03-01 Blurred images in full-field digital mammography are a problem in the UK Breast Screening Programme. Technical recalls may be due to blurring not being seen on lower resolution monitors used for review. This study assesses the visual detection of blurring on a 2.3-MP monitor and a 5-MP report grade monitor and proposes an observer standard for the visual detection of blurring on a 5-MP reporting grade monitor. 28 observers assessed 120 images for blurring; 20 images had no blurring present, whereas 100 images had blurring imposed through mathematical simulation at 0.2, 0.4, 0.6, 0.8 and 1.0 mm levels of motion. Technical recall rate for both monitors and angular size at each level of motion were calculated. χ 2 tests were used to test whether significant differences in blurring detection existed between 2.3- and 5-MP monitors. The technical recall rate for 2.3- and 5-MP monitors are 20.3% and 9.1%, respectively. The angular size for 0.2- to 1-mm motion varied from 55 to 275 arc s. The minimum amount of motion for visual detection of blurring in this study is 0.4 mm. For 0.2-mm simulated motion, there was no significant difference [χ 2 (1, N = 1095) = 1.61, p = 0.20] in blurring detection between the 2.3- and 5-MP monitors. According to this study, monitors ≤2.3 MP are not suitable for technical review of full-field digital mammography images for the detection of blur. Advances in knowledge: This research proposes the first observer standard for the visual detection of blurring. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5601529','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5601529">Blurred digital mammography images: an analysis of technical recall and observer detection performance</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Borgen, Rita; Kelly, Judith; Millington, Sara; Hilton, Beverley; Aspin, Rob; Lança, Carla; Hogg, Peter 2017-01-01 Objective: Blurred images in full-field digital mammography are a problem in the UK Breast Screening Programme. Technical recalls may be due to blurring not being seen on lower resolution monitors used for review. This study assesses the visual detection of blurring on a 2.3-MP monitor and a 5-MP report grade monitor and proposes an observer standard for the visual detection of blurring on a 5-MP reporting grade monitor. Methods: 28 observers assessed 120 images for blurring; 20 images had no blurring present, whereas 100 images had blurring imposed through mathematical simulation at 0.2, 0.4, 0.6, 0.8 and 1.0 mm levels of motion. Technical recall rate for both monitors and angular size at each level of motion were calculated. χ2 tests were used to test whether significant differences in blurring detection existed between 2.3- and 5-MP monitors. Results: The technical recall rate for 2.3- and 5-MP monitors are 20.3% and 9.1%, respectively. The angular size for 0.2- to 1-mm motion varied from 55 to 275 arc s. The minimum amount of motion for visual detection of blurring in this study is 0.4 mm. For 0.2-mm simulated motion, there was no significant difference [χ2 (1, N = 1095) = 1.61, p = 0.20] in blurring detection between the 2.3- and 5-MP monitors. Conclusion: According to this study, monitors ≤2.3 MP are not suitable for technical review of full-field digital mammography images for the detection of blur. Advances in knowledge: This research proposes the first observer standard for the visual detection of blurring. PMID:28134567 </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980038128','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980038128">Maynooth Optical Aeronomical Facility</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Mulligan, Francis J.; Niciejewski, Rick J. 1994-01-01 Ground-based measurements of upper atmospheric parameters, such as temperature and wind velocity, can be made by observing airglow emissions that have a well-defined altitude profile and that are known to be representative of the emitting region. We describe the optical observatory at Maynooth (53.23 deg N, 6.4 deg W) at which two instruments, a Fabry-Perot interferometer and a Fourier transform spectrometer, are used to record atmospheric airglow emissions in Ireland at visible and near-infrared wavelengths, respectively. Descriptions of the instruments, data acquisition, and analysis procedures are provided, together with some sample results. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12016864','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12016864">[Scanning electron microscope observation and image quantitative analysis of Hippocampi].</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Zhang, Z; Pu, Z; Xu, L; Xu, G; Wang, Q; Xu, G; Wu, L; Chen, J 1998-12-01 The "scale-like projects" on the derma of 3 species of Hippocampi, H. kuda Bleerer, H. trimaculatus Leach and H. japonicus Kaup were observed by scanning electron microscope (SEM). Results showed that some characteristics such us size, shape and type of arrangement of the "scale-like projects" can be considered as the evidence for microanalysis. Image quantitative analysis of the "scale-like project" was carried out on 45 pieces of photograph using area, long diameter, short diameter and shape factor as parameters. No difference among the different parts of the same species was observed, but significant differences were found among the above 3 species. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020083270','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020083270">Earth Observation Services Weather Imaging</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1992-01-01 Microprocessor-based systems for processing satellite data offer mariners real-time images of weather systems, day and night, of large areas or allow them to zoom in on a few square miles. Systems West markets these commercial image processing systems, which have significantly decreased the cost of satellite weather stations. The company was assisted by the EOCAP program, which provides government co-funding to encourage private investment in, and to broaden the use of, NASA-developed technology for analyzing information about Earth and ocean resources. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770032925&hterms=Tidal+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DTidal%2Bwaves','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770032925&hterms=Tidal+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DTidal%2Bwaves">Internal wave observations made with an airborne synthetic aperture imaging radar</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Elachi, C.; Apel, J. R. 1976-01-01 Synthetic aperture L-band radar flown aboard the NASA CV-990 has observed periodic striations on the ocean surface off the coast of Alaska which have been interpreted as tidally excited oceanic internal waves of less than 500 m length. These radar images are compared to photographic imagery of similar waves taken from Landsat 1. Both the radar and Landsat images reveal variations in reflectivity across each wave in a packet that range from low to high to normal. The variations point to the simultaneous existence of two mechanisms for the surface signatures of internal waves: roughening due to wave-current interactions, and smoothing due to slick formation. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8318E..0RO','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8318E..0RO">Creation of an ensemble of simulated cardiac cases and a human observer study: tools for the development of numerical observers for SPECT myocardial perfusion imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> O'Connor, J. Michael; Pretorius, P. Hendrik; Gifford, Howard C.; Licho, Robert; Joffe, Samuel; McGuiness, Matthew; Mehurg, Shannon; Zacharias, Michael; Brankov, Jovan G. 2012-02-01 Our previous Single Photon Emission Computed Tomography (SPECT) myocardial perfusion imaging (MPI) research explored the utility of numerical observers. We recently created two hundred and eighty simulated SPECT cardiac cases using Dynamic MCAT (DMCAT) and SIMIND Monte Carlo tools. All simulated cases were then processed with two reconstruction methods: iterative ordered subset expectation maximization (OSEM) and filtered back-projection (FBP). Observer study sets were assembled for both OSEM and FBP methods. Five physicians performed an observer study on one hundred and seventy-nine images from the simulated cases. The observer task was to indicate detection of any myocardial perfusion defect using the American Society of Nuclear Cardiology (ASNC) 17-segment cardiac model and the ASNC five-scale rating guidelines. Human observer Receiver Operating Characteristic (ROC) studies established the guidelines for the subsequent evaluation of numerical model observer (NO) performance. Several NOs were formulated and their performance was compared with the human observer performance. One type of NO was based on evaluation of a cardiac polar map that had been pre-processed using a gradient-magnitude watershed segmentation algorithm. The second type of NO was also based on analysis of a cardiac polar map but with use of a priori calculated average image derived from an ensemble of normal cases. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27828274','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27828274">Interference data correction methods for lunar observation with a large-aperture static imaging spectrometer.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Zhang, Geng; Wang, Shuang; Li, Libo; Hu, Xiuqing; Hu, Bingliang 2016-11-01 The lunar spectrum has been used in radiometric calibration and sensor stability monitoring for spaceborne optical sensors. A ground-based large-aperture static image spectrometer (LASIS) can be used to acquire the lunar spectral image for lunar radiance model improvement when the moon orbits over its viewing field. The lunar orbiting behavior is not consistent with the desired scanning speed and direction of LASIS. To correctly extract interferograms from the obtained data, a translation correction method based on image correlation is proposed. This method registers the frames to a reference frame to reduce accumulative errors. Furthermore, we propose a circle-matching-based approach to achieve even higher accuracy during observation of the full moon. To demonstrate the effectiveness of our approaches, experiments are run on true lunar observation data. The results show that the proposed approaches outperform the state-of-the-art methods. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9033E..5HL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9033E..5HL">Validation of an image-based technique to assess the perceptual quality of clinical chest radiographs with an observer study</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lin, Yuan; Choudhury, Kingshuk R.; McAdams, H. Page; Foos, David H.; Samei, Ehsan 2014-03-01 We previously proposed a novel image-based quality assessment technique1 to assess the perceptual quality of clinical chest radiographs. In this paper, an observer study was designed and conducted to systematically validate this technique. Ten metrics were involved in the observer study, i.e., lung grey level, lung detail, lung noise, riblung contrast, rib sharpness, mediastinum detail, mediastinum noise, mediastinum alignment, subdiaphragm-lung contrast, and subdiaphragm area. For each metric, three tasks were successively presented to the observers. In each task, six ROI images were randomly presented in a row and observers were asked to rank the images only based on a designated quality and disregard the other qualities. A range slider on the top of the images was used for observers to indicate the acceptable range based on the corresponding perceptual attribute. Five boardcertificated radiologists from Duke participated in this observer study on a DICOM calibrated diagnostic display workstation and under low ambient lighting conditions. The observer data were analyzed in terms of the correlations between the observer ranking orders and the algorithmic ranking orders. Based on the collected acceptable ranges, quality consistency ranges were statistically derived. The observer study showed that, for each metric, the averaged ranking orders of the participated observers were strongly correlated with the algorithmic orders. For the lung grey level, the observer ranking orders completely accorded with the algorithmic ranking orders. The quality consistency ranges derived from this observer study were close to these derived from our previous study. The observer study indicates that the proposed image-based quality assessment technique provides a robust reflection of the perceptual image quality of the clinical chest radiographs. The derived quality consistency ranges can be used to automatically predict the acceptability of a clinical chest radiograph. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PMB....56.5771D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PMB....56.5771D">Multi-observation PET image analysis for patient follow-up quantitation and therapy assessment</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> David, S.; Visvikis, D.; Roux, C.; Hatt, M. 2011-09-01 In positron emission tomography (PET) imaging, an early therapeutic response is usually characterized by variations of semi-quantitative parameters restricted to maximum SUV measured in PET scans during the treatment. Such measurements do not reflect overall tumor volume and radiotracer uptake variations. The proposed approach is based on multi-observation image analysis for merging several PET acquisitions to assess tumor metabolic volume and uptake variations. The fusion algorithm is based on iterative estimation using a stochastic expectation maximization (SEM) algorithm. The proposed method was applied to simulated and clinical follow-up PET images. We compared the multi-observation fusion performance to threshold-based methods, proposed for the assessment of the therapeutic response based on functional volumes. On simulated datasets the adaptive threshold applied independently on both images led to higher errors than the ASEM fusion and on clinical datasets it failed to provide coherent measurements for four patients out of seven due to aberrant delineations. The ASEM method demonstrated improved and more robust estimation of the evaluation leading to more pertinent measurements. Future work will consist in extending the methodology and applying it to clinical multi-tracer datasets in order to evaluate its potential impact on the biological tumor volume definition for radiotherapy applications. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active">19</li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active">20</li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/21455148-testing-hair-theorem-observations-electromagnetic-spectrum-ii-black-hole-images','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/21455148-testing-hair-theorem-observations-electromagnetic-spectrum-ii-black-hole-images">TESTING THE NO-HAIR THEOREM WITH OBSERVATIONS IN THE ELECTROMAGNETIC SPECTRUM. II. BLACK HOLE IMAGES</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Johannsen, Tim; Psaltis, Dimitrios, E-mail: timj@physics.arizona.ed, E-mail: dpsaltis@email.arizona.ed 2010-07-20 According to the no-hair theorem, all astrophysical black holes are fully described by their masses and spins. This theorem can be tested observationally by measuring (at least) three different multipole moments of the spacetimes of black holes. In this paper, we analyze images of black holes within a framework that allows us to calculate observables in the electromagnetic spectrum as a function of the mass, spin, and, independently, the quadrupole moment of a black hole. We show that a deviation of the quadrupole moment from the expected Kerr value leads to images of black holes that are either prolate ormore » oblate depending on the sign and magnitude of the deviation. In addition, there is a ring-like structure around the black hole shadow with a diameter of {approx}10 black hole masses that is substantially brighter than the image of the underlying accretion flow and that is independent of the astrophysical details of accretion flow models. We show that the shape of this ring depends directly on the mass, spin, and quadrupole moment of the black hole and can be used for an independent measurement of all three parameters. In particular, we demonstrate that this ring is highly circular for a Kerr black hole with a spin a {approx}< 0.9 M, independent of the observer's inclination, but becomes elliptical and asymmetric if the no-hair theorem is violated. Near-future very long baseline interferometric observations of Sgr A* will image this ring and may allow for an observational test of the no-hair theorem.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720003234&hterms=dim+light&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddim%2Blight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720003234&hterms=dim+light&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddim%2Blight">Experiment S030: Dim sky photography/orthicon</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Dunkelman, L.; Mercer, R. D.; Ney, E. P.; Hemenway, C. L. 1971-01-01 During Gemini missions, the image orthicon system was used to obtain photographic data on faint and diffuse astronomical phenomena. Results show that the photographs may be used to determine the airglow geometry. Although it was sensitive, the original photographic system was unsuitable for use in the study of dim and diffuse astronomical light sources. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930017533','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930017533">Wide-field direct CCD observations supporting the Astro-1 Space Shuttle mission's Ultraviolet Imaging Telescope</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Hintzen, Paul; Angione, Ron; Talbert, Freddie; Cheng, K.-P.; Smith, Eric; Stecher, Theodore P. 1993-01-01 Wide field direct CCD observations are being obtained to support and complement the vacuum-ultraviolet (VUV) images provided by Astro's Ultraviolet Imaging Telescope (UIT) during a Space Shuttle flight in December 1990. Because of the wide variety of projects addressed by UIT, the fields observed include (1) galactic supernova remnants such as the Cygnus Loop and globular clusters such as Omega Cen and M79; (2) the Magellanic Clouds, M33, M81, and other galaxies in the Local Group; and (3) rich clusters of galaxies, principally the Perseus cluster and Abell 1367. Ground-based observations have been obtained for virtually all of the Astro-1 UIT fields. The optical images allow identification of individual UV sources in each field and provide the long baseline in wavelength necessary for accurate analysis of UV-bright sources. To facilitate use of our optical images for analysis of UIT data and other projects, we plan to archive them, with the UIT images, at the National Space Science Data Center (NSSDC), where they will be universally accessible via anonymous FTP. The UIT, one of three telescopes comprising the Astro spacecraft, is a 38-cm f/9 Ritchey-Chretien telescope on which high quantum efficiency, solar-blind image tubes are used to record VUV images on photographic film. Five filters with passbands centered between 1250A and 2500A provide both VUV colors and a measurement of extinction via the 2200A dust feature. The resulting calibrated VUV pictures are 40 arcminutes in diameter at 2.5 arcseconds resolution. The capabilities of UIT, therefore, complement HST's WFPC: the latter has 40 times greater collecting area, while UIT's usable field has 170 times WFPC's field area. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22679605-decameter-stationary-type-iv-burst-imaging-observations-september','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22679605-decameter-stationary-type-iv-burst-imaging-observations-september">A DECAMETER STATIONARY TYPE IV BURST IN IMAGING OBSERVATIONS ON 2014 SEPTEMBER 6</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Koval, Artem; Chen, Yao; Feng, Shiwei 2016-08-01 First-of-its-kind radio imaging of a decameter solar stationary type IV radio burst has been presented in this paper. On 2014 September 6 the observations of type IV burst radio emission were carried out with the two-dimensional heliograph based on the Ukrainian T-shaped radio telescope (UTR-2), together with other telescope arrays. Starting at ∼09:55 UT and for ∼3 hr, the radio emission was kept within the observational session of UTR-2. The interesting observation covered the full evolution of this burst, “from birth to death.” During the event lifetime, two C-class solar X-ray flares with peak times 11:29 UT and 12:24 UTmore » took place. The time profile of this burst in radio has a double-humped shape that can be explained by injection of energetic electrons, accelerated by the two flares, into the burst source. According to the heliographic observations, we suggest that the burst source was confined within a high coronal loop, which was part of a relatively slow coronal mass ejection. The latter has been developed for several hours before the onset of the event. Through analysis of about 1.5 × 10{sup 6} heliograms (3700 temporal frames with 4096 images in each frame that correspond to the number of frequency channels), the radio burst source imaging shows a fascinating dynamical evolution. Both space-based ( GOES , SDO , SOHO , STEREO ) data and various ground-based instrumentation (ORFEES, NDA, RSTO, NRH) records have been used for this study.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22325154-su-sample-size-dependence-model-observers-estimating-low-contrast-detection-performance-from-ct-images','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22325154-su-sample-size-dependence-model-observers-estimating-low-contrast-detection-performance-from-ct-images">SU-E-I-46: Sample-Size Dependence of Model Observers for Estimating Low-Contrast Detection Performance From CT Images</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Reiser, I; Lu, Z 2014-06-01 Purpose: Recently, task-based assessment of diagnostic CT systems has attracted much attention. Detection task performance can be estimated using human observers, or mathematical observer models. While most models are well established, considerable bias can be introduced when performance is estimated from a limited number of image samples. Thus, the purpose of this work was to assess the effect of sample size on bias and uncertainty of two channelized Hotelling observers and a template-matching observer. Methods: The image data used for this study consisted of 100 signal-present and 100 signal-absent regions-of-interest, which were extracted from CT slices. The experimental conditions includedmore » two signal sizes and five different x-ray beam current settings (mAs). Human observer performance for these images was determined in 2-alternative forced choice experiments. These data were provided by the Mayo clinic in Rochester, MN. Detection performance was estimated from three observer models, including channelized Hotelling observers (CHO) with Gabor or Laguerre-Gauss (LG) channels, and a template-matching observer (TM). Different sample sizes were generated by randomly selecting a subset of image pairs, (N=20,40,60,80). Observer performance was quantified as proportion of correct responses (PC). Bias was quantified as the relative difference of PC for 20 and 80 image pairs. Results: For n=100, all observer models predicted human performance across mAs and signal sizes. Bias was 23% for CHO (Gabor), 7% for CHO (LG), and 3% for TM. The relative standard deviation, σ(PC)/PC at N=20 was highest for the TM observer (11%) and lowest for the CHO (Gabor) observer (5%). Conclusion: In order to make image quality assessment feasible in the clinical practice, a statistically efficient observer model, that can predict performance from few samples, is needed. Our results identified two observer models that may be suited for this task.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7263E..0PP','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7263E..0PP">Optimization of medical imaging display systems: using the channelized Hotelling observer for detecting lung nodules: experimental study</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Platisa, Ljiljana; Vansteenkiste, Ewout; Goossens, Bart; Marchessoux, Cédric; Kimpe, Tom; Philips, Wilfried 2009-02-01 Medical-imaging systems are designed to aid medical specialists in a specific task. Therefore, the physical parameters of a system need to optimize the task performance of a human observer. This requires measurements of human performance in a given task during the system optimization. Typically, psychophysical studies are conducted for this purpose. Numerical observer models have been successfully used to predict human performance in several detection tasks. Especially, the task of signal detection using a channelized Hotelling observer (CHO) in simulated images has been widely explored. However, there are few studies done for clinically acquired images that also contain anatomic noise. In this paper, we investigate the performance of a CHO in the task of detecting lung nodules in real radiographic images of the chest. To evaluate variability introduced by the limited available data, we employ a commonly used study of a multi-reader multi-case (MRMC) scenario. It accounts for both case and reader variability. Finally, we use the "oneshot" methods to estimate the MRMC variance of the area under the ROC curve (AUC). The obtained AUC compares well to those reported for human observer study on a similar data set. Furthermore, the "one-shot" analysis implies a fairly consistent performance of the CHO with the variance of AUC below 0.002. This indicates promising potential for numerical observers in optimization of medical imaging displays and encourages further investigation on the subject. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ISPAr42.3.2287Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ISPAr42.3.2287Z">Possibility of Cloudless Optical Remote Sensing Images Acquisition Study by Using Meteorological Satellite Observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Zhang, T.; Lei, B.; Hu, Y.; Liu, K.; Gan, Y. 2018-04-01 Optical remote sensing images have been widely used in feature interpretation and geo-information extraction. All the fundamental applications of optical remote sensing, are greatly influenced by cloud coverage. Generally, the availability of cloudless images depends on the meteorological conditions for a given area. In this study, the cloud total amount (CTA) products of the Fengyun (FY) satellite were introduced to explore the meteorological changes in a year over China. The cloud information of CTA products were tested by using ZY-3 satellite images firstly. CTA products from 2006 to 2017 were used to get relatively reliable results. The window period of cloudless images acquisition for different areas in China was then determined. This research provides a feasible way to get the cloudless images acquisition window by using meteorological observations. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss029e006855.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss029e006855.html">Air glow and Terminator view taken by the Expedition 29 crew</a> <a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2011-09-18 ISS029-E-006855 (18 Sept. 2011) --- This is one of a series of night time images photographed by one of the Expedition 29 crew members from the International Space Station. It features airglow, Earth?s terminator and parts of the Central Pacific Ocean. Nadir coordinates are 10.11 degrees north latitude and 169.92 degrees west longitude. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P13E..02R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P13E..02R">The Ultraviolet Spectrograph on the Europa Mission (Europa-UVS)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Retherford, K. D.; Gladstone, R.; Greathouse, T. K.; Steffl, A.; Davis, M. W.; Feldman, P. D.; McGrath, M. A.; Roth, L.; Saur, J.; Spencer, J. R.; Stern, S. A.; Pope, S.; Freeman, M. A.; Persyn, S. C.; Araujo, M. F.; Cortinas, S. C.; Monreal, R. M.; Persson, K. B.; Trantham, B. J.; Versteeg, M. H.; Walther, B. C. 2015-12-01 NASA's Europa multi-flyby mission is designed to provide a diversity of measurements suited to enrich our understanding of the potential habitability of this intriguing ocean world. The Europa mission's Ultraviolet Spectrograph, Europa-UVS, is the sixth in a series of successful ultraviolet imaging spectrographs (Rosetta-Alice, New Horizons Pluto-Alice, LRO-LAMP) and, like JUICE-UVS (now under Phase B development), is largely based on the most recent of these to fly, Juno-UVS. Europa-UVS observes photons in the 55-210 nm wavelength range, at moderate spectral and spatial resolution along a 7.5° slit. Three distinct apertures send light to the off-axis telescope mirror feeding the long-slit spectrograph: i) a main entrance airglow port is used for most observations (e.g., airglow, aurora, surface mapping, and stellar occultations); ii) a high-spatial-resolution port consists of a small hole in an additional aperture door, and is used for detailed observations of bright targets; and iii) a separate solar port allows for solar occultations, viewing at a 60° offset from the nominal payload boresight. Photon event time-tagging (pixel list mode) and programmable spectral imaging (histogram mode) allow for observational flexibility and optimal science data management. As on Juno-UVS, the effects of penetrating electron radiation on electronic parts and data quality are mitigated through contiguous shielding, filtering of pulse height amplitudes, management of high-voltage settings, and careful use of radiation-hard parts. The science goals of Europa-UVS are to: 1) Determine the composition & chemistry, source & sinks, and structure & variability of Europa's atmosphere, from equator to pole; 2) Search for and characterize active plumes in terms of global distribution, structure, composition, and variability; 3) Explore the surface composition & microphysics and their relation to endogenic & exogenic processes; and 4) Investigate how energy and mass flow in the Europa </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=S81-40830&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphoto%2Bimage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=S81-40830&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphoto%2Bimage">Earth observation photo taken by JPL with the Shuttle Imaging Radar-A</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1981-01-01 Earth observation photo taken by the Jet Propulsion Laboratory (JPL) with the Shuttle Imaging Radar-A (SIR-A). This image shows a 50 by 100 kilometer (30 by 60 mile) area of the Imperial Valley in Southern California and neighboring Mexico. The checkered patterns represent agricultural fields where different types of crops in different stages of growth are cultivated. The very bright areas are (top left to lower right) the U.S. towns of Brawley, Imperial, El Centro, Calexico and the Mexican city of Mexicali. The bright L-shaped line (upper right) is the All-American water canal. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSA11A1579K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSA11A1579K">The Sondrestrom Research Facility All-sky Imagers</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kendall, E. A.; Grill, M.; Gudmundsson, E.; Stromme, A. 2010-12-01 facility is a color all-sky imager (CASI). The CASI instrument is a low-cost Keo Scientific Ltd. system similar to cameras designed for the THEMIS satellite ground-based imaging network. This camera captures all visible wavelengths simultaneously at a higher data rate than the ASI. While it is not possible to resolve fine spectral features as with narrowband filters on the ASI, this camera provides context on wavelengths not covered by other imagers, and makes it much simpler to distinguish clouds from airglow and aurora. As with the ASI, this imager collects data during periods of dark skies and the images are posted to the web for community viewing. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22645710-observer-evaluation-metal-artifact-reduction-algorithm-applied-head-neck-cone-beam-computed-tomographic-images','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22645710-observer-evaluation-metal-artifact-reduction-algorithm-applied-head-neck-cone-beam-computed-tomographic-images">Observer Evaluation of a Metal Artifact Reduction Algorithm Applied to Head and Neck Cone Beam Computed Tomographic Images</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Korpics, Mark; Surucu, Murat; Mescioglu, Ibrahim Purpose and Objectives: To quantify, through an observer study, the reduction in metal artifacts on cone beam computed tomographic (CBCT) images using a projection-interpolation algorithm, on images containing metal artifacts from dental fillings and implants in patients treated for head and neck (H&N) cancer. Methods and Materials: An interpolation-substitution algorithm was applied to H&N CBCT images containing metal artifacts from dental fillings and implants. Image quality with respect to metal artifacts was evaluated subjectively and objectively. First, 6 independent radiation oncologists were asked to rank randomly sorted blinded images (before and after metal artifact reduction) using a 5-point rating scalemore » (1 = severe artifacts; 5 = no artifacts). Second, the standard deviation of different regions of interest (ROI) within each image was calculated and compared with the mean rating scores. Results: The interpolation-substitution technique successfully reduced metal artifacts in 70% of the cases. From a total of 60 images from 15 H&N cancer patients undergoing image guided radiation therapy, the mean rating score on the uncorrected images was 2.3 ± 1.1, versus 3.3 ± 1.0 for the corrected images. The mean difference in ranking score between uncorrected and corrected images was 1.0 (95% confidence interval: 0.9-1.2, P<.05). The standard deviation of each ROI significantly decreased after artifact reduction (P<.01). Moreover, a negative correlation between the mean rating score for each image and the standard deviation of the oral cavity and bilateral cheeks was observed. Conclusion: The interpolation-substitution algorithm is efficient and effective for reducing metal artifacts caused by dental fillings and implants on CBCT images, as demonstrated by the statistically significant increase in observer image quality ranking and by the decrease in ROI standard deviation between uncorrected and corrected images.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4667371','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4667371">Method for optimizing channelized quadratic observers for binary classification of large-dimensional image datasets</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Kupinski, M. K.; Clarkson, E. 2015-01-01 We present a new method for computing optimized channels for channelized quadratic observers (CQO) that is feasible for high-dimensional image data. The method for calculating channels is applicable in general and optimal for Gaussian distributed image data. Gradient-based algorithms for determining the channels are presented for five different information-based figures of merit (FOMs). Analytic solutions for the optimum channels for each of the five FOMs are derived for the case of equal mean data for both classes. The optimum channels for three of the FOMs under the equal mean condition are shown to be the same. This result is critical since some of the FOMs are much easier to compute. Implementing the CQO requires a set of channels and the first- and second-order statistics of channelized image data from both classes. The dimensionality reduction from M measurements to L channels is a critical advantage of CQO since estimating image statistics from channelized data requires smaller sample sizes and inverting a smaller covariance matrix is easier. In a simulation study we compare the performance of ideal and Hotelling observers to CQO. The optimal CQO channels are calculated using both eigenanalysis and a new gradient-based algorithm for maximizing Jeffrey's divergence (J). Optimal channel selection without eigenanalysis makes the J-CQO on large-dimensional image data feasible. PMID:26366764 </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...810...46H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...810...46H">Cool Transition Region Loops Observed by the Interface Region Imaging Spectrograph</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Huang, Zhenghua; Xia, Lidong; Li, Bo; Madjarska, Maria S. 2015-09-01 We report on the first Interface Region Imaging Spectrograph (IRIS) study of cool transition region loops, a class of loops that has received little attention in the literature. A cluster of such loops was observed on the solar disk in active region NOAA11934, in the Si iv 1402.8 Å spectral raster and 1400 Å slit-jaw images. We divide the loops into three groups and study their dynamics. The first group comprises relatively stable loops, with 382-626 km cross-sections. Observed Doppler velocities are suggestive of siphon flows, gradually changing from -10 km s-1 at one end to 20 km s-1 at the other end of the loops. Nonthermal velocities of 15 ˜ 25 km s-1 were determined. Magnetic cancellation with a rate of 1015 Mx s-1 is found at the blueshifted footpoints. These physical properties suggest that these loops are impulsively heated by magnetic reconnection, and the siphon flows play an important role in the energy redistribution. The second group corresponds to two footpoints rooted in mixed-magnetic-polarity regions, where magnetic cancellation with a rate of 1015 Mx s-1 and explosive-event line profiles with enhanced wings of up to 200 km s-1 were observed. In the third group, interaction between two cool loop systems is observed. Evidence for magnetic reconnection between the two loop systems is reflected in the explosive-event line profiles and magnetic cancellation with a rate of 3× {10}15 Mx s-1 observed in the corresponding area. The IRIS has provided opportunity for in-depth investigations of cool transition region loops. Further numerical experiments are crucial for understanding their physics and their roles in the coronal heating processes. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2715171','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2715171">Observer efficiency in discrimination tasks simulating malignant and benign breast lesions imaged with ultrasound</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Abbey, Craig K.; Zemp, Roger J.; Liu, Jie; Lindfors, Karen K.; Insana, Michael F. 2009-01-01 We investigate and extend the ideal observer methodology developed by Smith and Wagner to detection and discrimination tasks related to breast sonography. We provide a numerical approach for evaluating the ideal observer acting on radio-frequency (RF) frame data, which involves inversion of large nonstationary covariance matrices, and we describe a power-series approach to computing this inverse. Considering a truncated power series suggests that the RF data be Wiener-filtered before forming the final envelope image. We have compared human performance for Wiener-filtered and conventional B-mode envelope images using psychophysical studies for 5 tasks related to breast cancer classification. We find significant improvements in visual detection and discrimination efficiency in four of these five tasks. We also use the Smith-Wagner approach to distinguish between human and processing inefficiencies, and find that generally the principle limitation comes from the information lost in computing the final envelope image. PMID:16468454 </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014amos.confE..86O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014amos.confE..86O">Optical Observation, Image-processing, and Detection of Space Debris in Geosynchronous Earth Orbit</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Oda, H.; Yanagisawa, T.; Kurosaki, H.; Tagawa, M. 2014-09-01 We report on optical observations and an efficient detection method of space debris in the geosynchronous Earth orbit (GEO). We operate our new Australia Remote Observatory (ARO) where an 18 cm optical telescope with a charged-coupled device (CCD) camera covering a 3.14-degree field of view is used for GEO debris survey, and analyse datasets of successive CCD images using the line detection method (Yanagisawa and Nakajima 2005). In our operation, the exposure time of each CCD image is set to be 3 seconds (or 5 seconds), and the time interval of CCD shutter open is about 4.7 seconds (or 6.7 seconds). In the line detection method, a sufficient number of sample objects are taken from each image based on their shape and intensity, which includes not only faint signals but also background noise (we take 500 sample objects from each image in this paper). Then we search a sequence of sample objects aligning in a straight line in the successive images to exclude the noise sample. We succeed in detecting faint signals (down to about 1.8 sigma of background noise) by applying the line detection method to 18 CCD images. As a result, we detected about 300 GEO objects up to magnitude of 15.5 among 5 nights data. We also calculate orbits of objects detected using the Simplified General Perturbations Satellite Orbit Model 4(SGP4), and identify the objects listed in the two-line-element (TLE) data catalogue publicly provided by the U.S. Strategic Command (USSTRATCOM). We found that a certain amount of our detections are new objects that are not contained in the catalogue. We conclude that our ARO and detection method posse a high efficiency detection of GEO objects despite the use of comparatively-inexpensive observation and analysis system. We also describe the image-processing specialized for the detection of GEO objects (not for usual astronomical objects like stars) in this paper. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870060961&hterms=Evidence+atomic+theory&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DEvidence%2Batomic%2Btheory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870060961&hterms=Evidence+atomic+theory&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DEvidence%2Batomic%2Btheory">Hydrogen Balmer alpha intensity distributions and line profiles from multiple scattering theory using realistic geocoronal models</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Anderson, D. E., Jr.; Meier, R. R.; Hodges, R. R., Jr.; Tinsley, B. A. 1987-01-01 The H Balmer alpha nightglow is investigated by using Monte Carlo models of asymmetric geocoronal atomic hydrogen distributions as input to a radiative transfer model of solar Lyman-beta radiation in the thermosphere and atmosphere. It is shown that it is essential to include multiple scattering of Lyman-beta radiation in the interpretation of Balmer alpha airglow data. Observations of diurnal variation in the Balmer alpha airglow showing slightly greater intensities in the morning relative to evening are consistent with theory. No evidence is found for anything other than a single sinusoidal diurnal variation of exobase density. Dramatic changes in effective temperature derived from the observed Balmer alpha line profiles are expected on the basis of changing illumination conditions in the thermosphere and exosphere as different regions of the sky are scanned. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992lest.rept....3K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992lest.rept....3K">GAP: yet another image processing system for solar observations.</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Keller, C. U. GAP is a versatile, interactive image processing system for analyzing solar observations, in particular extended time sequences, and for preparing publication quality figures. It consists of an interpreter that is based on a language with a control flow similar to PASCAL and C. The interpreter may be accessed from a command line editor and from user-supplied functions, procedures, and command scripts. GAP is easily expandable via external FORTRAN programs that are linked to the GAP interface routines. The current version of GAP runs on VAX, DECstation, Sun, and Apollo computers. Versions for MS-DOS and OS/2 are in preparation. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890002224','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890002224">Structural anomalies in undoped Gallium Arsenide observed in high resolution diffraction imaging with monochromatic synchrotron radiation</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Steiner, B.; Kuriyama, M.; Dobbyn, R. C.; Laor, U.; Larson, D.; Brown, M. 1988-01-01 Novel, streak-like disruption features restricted to the plane of diffraction have recently been observed in images obtained by synchrotron radiation diffraction from undoped, semi-insulating gallium arsenide crystals. These features were identified as ensembles of very thin platelets or interfaces lying in (110) planes, and a structural model consisting of antiphase domain boundaries was proposed. We report here the other principal features observed in high resolution monochromatic synchrotron radiation diffraction images: (quasi) cellular structure; linear, very low-angle subgrain boundaries in (110) directions, and surface stripes in a (110) direction. In addition, we report systematic differences in the acceptance angle for images involving various diffraction vectors. When these observations are considered together, a unifying picture emerges. The presence of ensembles of thin (110) antiphase platelet regions or boundaries is generally consistent not only with the streak-like diffraction features but with the other features reported here as well. For the formation of such regions we propose two mechanisms, operating in parallel, that appear to be consistent with the various defect features observed by a variety of techniques. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890058656&hterms=gallium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dgallium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890058656&hterms=gallium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dgallium">Structural anomalies in undoped gallium arsenide observed in high-resolution diffraction imaging with monochromatic synchrotron radiation</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Steiner, B.; Kuriyama, M.; Dobbyn, R. C.; Laor, U.; Larson, D. 1989-01-01 Novel, streak-like disruption features restricted to the plane of diffraction have recently been observed in images obtained by synchrotron radiation diffraction from undoped, semi-insulating gallium arsenide crystals. These features were identified as ensembles of very thin platelets or interfaces lying in (110) planes, and a structural model consisting of antiphase domain boundaries was proposed. We report here the other principal features observed in high resolution monochromatic synchrotron radiation diffraction images: (quasi) cellular structure; linear, very low-angle subgrain boundaries in (110) directions, and surface stripes in a (110) direction. In addition, we report systematic differences in the acceptance angle for images involving various diffraction vectors. When these observations are considered together, a unifying picture emerges. The presence of ensembles of thin (110) antiphase platelet regions or boundaries is generally consistent not only with the streak-like diffraction features but with the other features reported here as well. For the formation of such regions we propose two mechanisms, operating in parallel, that appear to be consistent with the various defect features observed by a variety of techniques. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active">20</li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active">21</li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28983493','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28983493">Use of a channelized Hotelling observer to assess CT image quality and optimize dose reduction for iteratively reconstructed images.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Favazza, Christopher P; Ferrero, Andrea; Yu, Lifeng; Leng, Shuai; McMillan, Kyle L; McCollough, Cynthia H 2017-07-01 The use of iterative reconstruction (IR) algorithms in CT generally decreases image noise and enables dose reduction. However, the amount of dose reduction possible using IR without sacrificing diagnostic performance is difficult to assess with conventional image quality metrics. Through this investigation, achievable dose reduction using a commercially available IR algorithm without loss of low contrast spatial resolution was determined with a channelized Hotelling observer (CHO) model and used to optimize a clinical abdomen/pelvis exam protocol. A phantom containing 21 low contrast disks-three different contrast levels and seven different diameters-was imaged at different dose levels. Images were created with filtered backprojection (FBP) and IR. The CHO was tasked with detecting the low contrast disks. CHO performance indicated dose could be reduced by 22% to 25% without compromising low contrast detectability (as compared to full-dose FBP images) whereas 50% or more dose reduction significantly reduced detection performance. Importantly, default settings for the scanner and protocol investigated reduced dose by upward of 75%. Subsequently, CHO-based protocol changes to the default protocol yielded images of higher quality and doses more consistent with values from a larger, dose-optimized scanner fleet. CHO assessment provided objective data to successfully optimize a clinical CT acquisition protocol. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.9204L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.9204L">Characteristics of mesospheric gravity waves over the southeastern Tibetan Plateau region</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Li, Qinzeng; Xu, Jiyao; Liu, Xiao; Yuan, Wei; Chen, Jinsong 2016-09-01 The Tibetan Plateau (TP), known as "Third Pole" of the Earth, has important influences on global climates and local weather. An important objective in present study is to investigate how orographic features of the TP affect the geographical distributions of gravity wave (GW) sources. Three-year OH airglow images (November 2011 to October 2014) from Qujing (25.6°N, 103.7°E) were used to study the characteristics of GWs over the southeastern TP region. Along with the almost concurrent and collocated meteor radar wind measurements and temperature data from SABER/TIMED satellite, the propagation conditions of three types of GWs (freely propagating, ducted, or evanescent) were estimated. Most of GWs exhibited ducted or evanescent characteristics. Almost all GWs propagate southeastward in winter. The GW propagation directions in winter are significantly different from other airglow imager observations at northern middle latitudes. Wind data and convective precipitation fields from the European Centre for Medium-Range Weather Forecasts reanalysis data are used to study the sources of GWs on the edge of the TP. Using backward ray-tracing analysis, we find that most of the mesospheric freely propagating GWs are located in or near the large wind shear intensity region ( 10 km- 17 km) on the southeastern edge of the TP in spring and winter. The averaged value of momentum flux is 11.6 ± 5.2 m2/s2 in winter and 7.5 ± 3.1 m2/s2 in summer. This work will provide valuable information for the GW parameterization schemes in general circulation models in TP region. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...833...22C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...833...22C">Undercover EUV Solar Jets Observed by the Interface Region Imaging Spectrograph</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Chen, N.-H.; Innes, D. E. 2016-12-01 It is well-known that extreme ultraviolet (EUV) emission emitted at the solar surface is absorbed by overlying cool plasma. Especially in active regions, dark lanes in EUV images suggest that much of the surface activity is obscured. Simultaneous observations from the Interface Region Imaging Spectrograph, consisting of UV spectra and slit-jaw images (SJI), give vital information with sub-arcsecond spatial resolution on the dynamics of jets not seen in EUV images. We studied a series of small jets from recently formed bipole pairs beside the trailing spot of active region 11991, which occurred on 2014 March 5 from 15:02:21 UT to 17:04:07 UT. Collimated outflows with bright roots were present in SJI 1400 Å (transition region) and 2796 Å (upper chromosphere) that were mostly not seen in Atmospheric Imaging Assembly (AIA) 304 Å (transition region) and AIA 171 Å (lower corona) images. The Si IV spectra show a strong blue wing enhancement, but no red wing, in the line profiles of the ejecta for all recurrent jets, indicating outward flows without twists. We see two types of Mg II line profiles produced by the jets spires: reversed and non-reversed. Mg II lines remain optically thick, but turn optically thin in the highly Doppler shifted wings. The energy flux contained in each recurrent jet is estimated using a velocity differential emission measure technique that measures the emitting power of the plasma as a function of the line-of-sight velocity. We found that all the recurrent jets release similar energy (108 erg cm-2 s-1) toward the corona and the downward component is less than 3%. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AAS...22930303S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AAS...22930303S">Imaging Protoplanets: Observing Transition Disks with Non-Redundant Masking</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sallum, Stephanie 2017-01-01 Transition disks - protoplanetary disks with inner, solar system sized clearings - may be shaped by young planets. Directly imaging protoplanets in these objects requires high contrast and resolution, making them promising targets for future extremely large telescopes. The interferometric technique of non-redundant masking (NRM) is well suited for these observations, enabling companion detection for contrasts of 1:100 - 1:1000 at or within the diffraction limit. My dissertation focuses on searching for and characterizing companions in transition disk clearings using NRM. I will briefly describe the technique and present spatially resolved observations of the T Cha and LkCa 15 transition disks. Both of these objects hosted posited substellar companions. However multi-epoch T Cha datasets cannot be explained by planets orbiting in the disk plane. Conversely, LkCa 15 data taken with the Large Binocular Telescope (LBT) in single-aperture mode reveal the presence of multiple forming planets. The dual aperture LBT will provide triple the angular resolution of these observations, dramatically increasing the phase space for exoplanet detection. I will also present new results from the dual-aperture LBT, with similar resolution to that expected for next generation facilities like GMT. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900003993','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900003993">EIT: Solar corona synoptic observations from SOHO with an Extreme-ultraviolet Imaging Telescope</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Delaboudiniere, J. P.; Gabriel, A. H.; Artzner, G. E.; Michels, D. J.; Dere, K. P.; Howard, R. A.; Catura, R.; Stern, R.; Lemen, J.; Neupert, W. 1988-01-01 The Extreme-ultraviolet Imaging Telescope (EIT) of SOHO (solar and heliospheric observatory) will provide full disk images in emission lines formed at temperatures that map solar structures ranging from the chromospheric network to the hot magnetically confined plasma in the corona. Images in four narrow bandpasses will be obtained using normal incidence multilayered optics deposited on quadrants of a Ritchey-Chretien telescope. The EIT is capable of providing a uniform one arc second resolution over its entire 50 by 50 arc min field of view. Data from the EIT will be extremely valuable for identifying and interpreting the spatial and temperature fine structures of the solar atmosphere. Temporal analysis will provide information on the stability of these structures and identify dynamical processes. EIT images, issued daily, will provide the global corona context for aid in unifying the investigations and in forming the observing plans for SOHO coronal instruments. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9913E..4GT','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9913E..4GT">Image processing improvement for optical observations of space debris with the TAROT telescopes</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Thiebaut, C.; Theron, S.; Richard, P.; Blanchet, G.; Klotz, A.; Boër, M. 2016-07-01 CNES is involved in the Inter-Agency Space Debris Coordination Committee (IADC) and is observing space debris with two robotic ground based fully automated telescopes called TAROT and operated by the CNRS. An image processing algorithm devoted to debris detection in geostationary orbit is implemented in the standard pipeline. Nevertheless, this algorithm is unable to deal with debris tracking mode images, this mode being the preferred one for debris detectability. We present an algorithm improvement for this mode and give results in terms of false detection rate. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4651348','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4651348">Pigeons (Columba livia) as Trainable Observers of Pathology and Radiology Breast Cancer Images</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Levenson, Richard M.; Krupinski, Elizabeth A.; Navarro, Victor M.; Wasserman, Edward A. 2015-01-01 Pathologists and radiologists spend years acquiring and refining their medically essential visual skills, so it is of considerable interest to understand how this process actually unfolds and what image features and properties are critical for accurate diagnostic performance. Key insights into human behavioral tasks can often be obtained by using appropriate animal models. We report here that pigeons (Columba livia)—which share many visual system properties with humans—can serve as promising surrogate observers of medical images, a capability not previously documented. The birds proved to have a remarkable ability to distinguish benign from malignant human breast histopathology after training with differential food reinforcement; even more importantly, the pigeons were able to generalize what they had learned when confronted with novel image sets. The birds’ histological accuracy, like that of humans, was modestly affected by the presence or absence of color as well as by degrees of image compression, but these impacts could be ameliorated with further training. Turning to radiology, the birds proved to be similarly capable of detecting cancer-relevant microcalcifications on mammogram images. However, when given a different (and for humans quite difficult) task—namely, classification of suspicious mammographic densities (masses)—the pigeons proved to be capable only of image memorization and were unable to successfully generalize when shown novel examples. The birds’ successes and difficulties suggest that pigeons are well-suited to help us better understand human medical image perception, and may also prove useful in performance assessment and development of medical imaging hardware, image processing, and image analysis tools. PMID:26581091 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26581091','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26581091">Pigeons (Columba livia) as Trainable Observers of Pathology and Radiology Breast Cancer Images.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Levenson, Richard M; Krupinski, Elizabeth A; Navarro, Victor M; Wasserman, Edward A 2015-01-01 Pathologists and radiologists spend years acquiring and refining their medically essential visual skills, so it is of considerable interest to understand how this process actually unfolds and what image features and properties are critical for accurate diagnostic performance. Key insights into human behavioral tasks can often be obtained by using appropriate animal models. We report here that pigeons (Columba livia)-which share many visual system properties with humans-can serve as promising surrogate observers of medical images, a capability not previously documented. The birds proved to have a remarkable ability to distinguish benign from malignant human breast histopathology after training with differential food reinforcement; even more importantly, the pigeons were able to generalize what they had learned when confronted with novel image sets. The birds' histological accuracy, like that of humans, was modestly affected by the presence or absence of color as well as by degrees of image compression, but these impacts could be ameliorated with further training. Turning to radiology, the birds proved to be similarly capable of detecting cancer-relevant microcalcifications on mammogram images. However, when given a different (and for humans quite difficult) task-namely, classification of suspicious mammographic densities (masses)-the pigeons proved to be capable only of image memorization and were unable to successfully generalize when shown novel examples. The birds' successes and difficulties suggest that pigeons are well-suited to help us better understand human medical image perception, and may also prove useful in performance assessment and development of medical imaging hardware, image processing, and image analysis tools. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSH51D..02L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSH51D..02L">Solar Polar Imager: Observing Coronal Transients from a New Perspective (Invited)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Liewer, P. C. 2013-12-01 The heliophysics community has long recognized the need for a mission to observe the Sun and corona from a polar perspective. One mission concept, the Solar Polar Imager (SPI), has been studied extensively (Liewer et al in NASA Space Science Vision Missions, 2008). In this concept, a solar sail is used to place a spacecraft in a circular 0.48-AU heliocentric orbit with an inclination of ~75 degrees. This orbit enables crucial observations not possible from lower latitude perspectives. Magnetograph and Doppler observations from a polar vantage point would revolutionize our understanding of the mechanism of solar activity cycles, polar magnetic field reversals, the internal structure and dynamics of the Sun and its atmosphere. The rapid 4-month polar orbit combined with both in situ and remote sensing instrumentation further enables unprecedented studies of the physical connection between the Sun, the solar wind, and solar energetic particles. From the polar perspective, white light imagers could be used to track CMEs and predict their arrival at Earth (as demonstrated by STEREO). SPI is also well suited to study the relative roles of CME-driven shock versus flare-associated processes in solar energetic particle acceleration. With the circular 0.48 AU orbit, solar energetic particles could be more easily traced to their sources and their variation with latitude can be studied at a constant radius. This talk will discuss the science objectives, instrumentation and mission design for the SPI mission. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ASPC..483..319S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ASPC..483..319S">Imaging the Moon II: Webcam CCD Observations and Analysis (a Two-Week Lab for Non-Majors)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sato, T. 2014-07-01 Imaging the Moon is a successful two-week lab involving real sky observations of the Moon in which students make telescopic observations and analyze their own images. Originally developed around the 35 mm film camera, a common household object adapted for astronomical work, the lab now uses webcams as film photography has evolved into an obscure specialty technology and increasing numbers of students have little familiarity with it. The printed circuit board with the CCD is harvested from a commercial webcam and affixed to a tube to mount on a telescope in place of an eyepiece. Image frames are compiled to form a lunar mosaic, and crater sizes are measured. Students also work through the logistical steps of telescope time assignment and scheduling. They learn to keep a schedule and work with uncertainties of weather in ways paralleling research observations. Because there is no need for a campus observatory, this lab can be replicated at a wide variety of institutions. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9652E..0KG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9652E..0KG">Versatile illumination platform and fast optical switch to give standard observation camera gated active imaging capacity</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Grasser, R.; Peyronneaudi, Benjamin; Yon, Kevin; Aubry, Marie 2015-10-01 CILAS, subsidiary of Airbus Defense and Space, develops, manufactures and sales laser-based optronics equipment for defense and homeland security applications. Part of its activity is related to active systems for threat detection, recognition and identification. Active surveillance and active imaging systems are often required to achieve identification capacity in case for long range observation in adverse conditions. In order to ease the deployment of active imaging systems often complex and expensive, CILAS suggests a new concept. It consists on the association of two apparatus working together. On one side, a patented versatile laser platform enables high peak power laser illumination for long range observation. On the other side, a small camera add-on works as a fast optical switch to select photons with specific time of flight only. The association of the versatile illumination platform and the fast optical switch presents itself as an independent body, so called "flash module", giving to virtually any passive observation systems gated active imaging capacity in NIR and SWIR. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29475259','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29475259">Dual-polarized light-field imaging micro-system via a liquid-crystal microlens array for direct three-dimensional observation.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Xin, Zhaowei; Wei, Dong; Xie, Xingwang; Chen, Mingce; Zhang, Xinyu; Liao, Jing; Wang, Haiwei; Xie, Changsheng 2018-02-19 Light-field imaging is a crucial and straightforward way of measuring and analyzing surrounding light worlds. In this paper, a dual-polarized light-field imaging micro-system based on a twisted nematic liquid-crystal microlens array (TN-LCMLA) for direct three-dimensional (3D) observation is fabricated and demonstrated. The prototyped camera has been constructed by integrating a TN-LCMLA with a common CMOS sensor array. By switching the working state of the TN-LCMLA, two orthogonally polarized light-field images can be remapped through the functioned imaging sensors. The imaging micro-system in conjunction with the electric-optical microstructure can be used to perform polarization and light-field imaging, simultaneously. Compared with conventional plenoptic cameras using liquid-crystal microlens array, the polarization-independent light-field images with a high image quality can be obtained in the arbitrary polarization state selected. We experimentally demonstrate characters including a relatively wide operation range in the manipulation of incident beams and the multiple imaging modes, such as conventional two-dimensional imaging, light-field imaging, and polarization imaging. Considering the obvious features of the TN-LCMLA, such as very low power consumption, providing multiple imaging modes mentioned, simple and low-cost manufacturing, the imaging micro-system integrated with this kind of liquid-crystal microstructure driven electrically presents the potential capability of directly observing a 3D object in typical scattering media. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29708194','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29708194">A simple method for low-contrast detectability, image quality and dose optimisation with CT iterative reconstruction algorithms and model observers.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Bellesi, Luca; Wyttenbach, Rolf; Gaudino, Diego; Colleoni, Paolo; Pupillo, Francesco; Carrara, Mauro; Braghetti, Antonio; Puligheddu, Carla; Presilla, Stefano 2017-01-01 The aim of this work was to evaluate detection of low-contrast objects and image quality in computed tomography (CT) phantom images acquired at different tube loadings (i.e. mAs) and reconstructed with different algorithms, in order to find appropriate settings to reduce the dose to the patient without any image detriment. Images of supraslice low-contrast objects of a CT phantom were acquired using different mAs values. Images were reconstructed using filtered back projection (FBP), hybrid and iterative model-based methods. Image quality parameters were evaluated in terms of modulation transfer function; noise, and uniformity using two software resources. For the definition of low-contrast detectability, studies based on both human (i.e. four-alternative forced-choice test) and model observers were performed across the various images. Compared to FBP, image quality parameters were improved by using iterative reconstruction (IR) algorithms. In particular, IR model-based methods provided a 60% noise reduction and a 70% dose reduction, preserving image quality and low-contrast detectability for human radiological evaluation. According to the model observer, the diameters of the minimum detectable detail were around 2 mm (up to 100 mAs). Below 100 mAs, the model observer was unable to provide a result. IR methods improve CT protocol quality, providing a potential dose reduction while maintaining a good image detectability. Model observer can in principle be useful to assist human performance in CT low-contrast detection tasks and in dose optimisation. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010003574','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010003574">Observations of Leonid Meteors Using a Mid-Wave Infrared Imaging Spectrograph</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Rossano, G. S.; Russell, R. W.; Lynch, D. K.; Tessensohn, T. K.; Warren, D.; Jenniskens, P.; DeVincenzi, Donald L. (Technical Monitor) 2000-01-01 We report broadband 3-5.5 micrometer detections of two Leonid meteors observed during the 1998 Leonid Multi-Instrument Aircraft Campaign. Each meteor was detected at only one position along their trajectory just prior to the point of maximum light emission. We describe the particular aspects of the Aerospace Corp. Mid-wave Infra-Red Imaging Spectrograph (MIRIS) developed for the observation of short duration transient events that impact its ability to detect Leonid meteors. This instrument had its first deployment during the 1998 Leonid MAC. We infer from our observations that the mid-infrared light curves of two Leonid meteors differed from the visible light curve. At the points of detection, the infrared emission in the MIRIS passband was 25 +/- 4 times that at optical wavelengths for both meteors. In addition, we find an upper limit of 800 K for the solid body temperature of the brighter meteor we observed, at the point in the trajectory where we made our mid-wave infrared detection. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810065306&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810065306&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtwilight">Observations of the Ca/+/ twilight airglow from intermediate layers of ionization</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Tepley, C. A.; Meriwether, J. W., Jr.; Walker, J. C. G.; Mathews, J. D. 1981-01-01 Optical and incoherent scatter radar techniques are applied to detect the presence of Ca(+) in lower thermospheric intermediate layers over Arecibo. The Arecibo 430 MHz radar is used to measure electron densities, and the altitude distribution and density of the calcium ion is inferred from the variation of twilight resonant scattering with solar depression angle. Ca(+) and electron column densities are compared, and results indicate that the composition of low-altitude intermediate layers is 2% Ca(+), which is consistent with rocket mass spectrometer measurements. Fe(+) and Mg(+) ultraviolet resonance lines are not detected from the ground due to ozone absorbing all radiation short of 3000 A, and measurements of the neutral iron resonance line at 3860 A show that an atmospheric continuum may result in overestimations of emission rates at high solar depression angles. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22660958-undercover-euv-solar-jets-observed-interface-region-imaging-spectrograph','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22660958-undercover-euv-solar-jets-observed-interface-region-imaging-spectrograph">UNDERCOVER EUV SOLAR JETS OBSERVED BY THE INTERFACE REGION IMAGING SPECTROGRAPH</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Chen, N.-H.; Innes, D. E. It is well-known that extreme ultraviolet (EUV) emission emitted at the solar surface is absorbed by overlying cool plasma. Especially in active regions, dark lanes in EUV images suggest that much of the surface activity is obscured. Simultaneous observations from the Interface Region Imaging Spectrograph, consisting of UV spectra and slit-jaw images (SJI), give vital information with sub-arcsecond spatial resolution on the dynamics of jets not seen in EUV images. We studied a series of small jets from recently formed bipole pairs beside the trailing spot of active region 11991, which occurred on 2014 March 5 from 15:02:21 UT tomore » 17:04:07 UT. Collimated outflows with bright roots were present in SJI 1400 Å (transition region) and 2796 Å (upper chromosphere) that were mostly not seen in Atmospheric Imaging Assembly (AIA) 304 Å (transition region) and AIA 171 Å (lower corona) images. The Si iv spectra show a strong blue wing enhancement, but no red wing, in the line profiles of the ejecta for all recurrent jets, indicating outward flows without twists. We see two types of Mg ii line profiles produced by the jets spires: reversed and non-reversed. Mg ii lines remain optically thick, but turn optically thin in the highly Doppler shifted wings. The energy flux contained in each recurrent jet is estimated using a velocity differential emission measure technique that measures the emitting power of the plasma as a function of the line-of-sight velocity. We found that all the recurrent jets release similar energy (10{sup 8} erg cm{sup −2} s{sup −1}) toward the corona and the downward component is less than 3%.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9147E..83W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9147E..83W">Gemini planet imager observational calibrations VII: on-sky polarimetric performance of the Gemini planet imager</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Wiktorowicz, Sloane J.; Millar-Blanchaer, Max; Perrin, Marshall D.; Graham, James R.; Fitzgerald, Michael P.; Maire, Jérôme; Ingraham, Patrick; Savransky, Dmitry; Macintosh, Bruce A.; Thomas, Sandrine J.; Chilcote, Jeffrey K.; Draper, Zachary H.; Song, Inseok; Cardwell, Andrew; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Rantakyrö, Fredrik; Sadakuni, Naru 2014-07-01 We present on-sky polarimetric observations with the Gemini Planet Imager (GPI) obtained at straight Cassegrain focus on the Gemini South 8-m telescope. Observations of polarimetric calibrator stars, ranging from nearly un- polarized to strongly polarized, enable determination of the combined telescope and instrumental polarization. We find the conversion of Stokes I to linear and circular instrumental polarization in the instrument frame to be I --> (QIP, UIP, PIP, VIP) = (-0.037 +/- 0.010%, +0.4338 +/- 0.0075%, 0.4354 +/- 0.0075%, -6.64 +/- 0.56%). Such precise measurement of instrumental polarization enables ~0.1% absolute accuracy in measurements of linear polarization, which together with GPI's high contrast will allow GPI to explore scattered light from circumstellar disk in unprecedented detail, conduct observations of a range of other astronomical bodies, and potentially even study polarized thermal emission from young exoplanets. Observations of unpolarized standard stars also let us quantify how well GPI's differential polarimetry mode can suppress the stellar PSF halo. We show that GPI polarimetry achieves cancellation of unpolarized starlight by factors of 100-200, reaching the photon noise limit for sensitivity to circumstellar scattered light for all but the smallest separations at which the calibration for instrumental polarization currently sets the limit. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ASInC...4..189O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ASInC...4..189O">First light observations with TIFR Near Infrared Imaging Camera (TIRCAM-II)</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ojha, D. K.; Ghosh, S. K.; D'Costa, S. L. A.; Naik, M. B.; Sandimani, P. R.; Poojary, S. S.; Bhagat, S. B.; Jadhav, R. B.; Meshram, G. S.; Bakalkar, C. B.; Ramaprakash, A. N.; Mohan, V.; Joshi, J. TIFR near infrared imaging camera (TIRCAM-II) is based on the Aladdin III Quadrant InSb focal plane array (512×512 pixels; 27.6 μm pixel size; sensitive between 1 - 5.5 μm). TIRCAM-II had its first engineering run with the 2 m IUCAA telescope at Girawali during February - March 2011. The first light observations with TIRCAM-II were quite successful. Several infrared standard with TIRCAM-II were quite successful. Several infrared standard stars, the Trapezium Cluster in Orion region, McNeil's nebula, etc., were observed in the J, K and in a narrow-band at 3.6 μm (nbL). In the nbL band, some bright stars could be detected from the Girawali site. The performance of TIRCAM-II is discussed in the light of preliminary observations in near infrared bands. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993JGR....9817183G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993JGR....9817183G">Galileo imaging observations of Lunar Maria and related deposits</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Greeley, Ronald; Kadel, Steven D.; Williams, David A.; Gaddis, Lisa R.; Head, James W.; McEwen, Alfred S.; Murchie, Scott L.; Nagel, Engelbert; Neukum, Gerhard; Pieters, Carle M.; Sunshine, Jessica M.; Wagner, Roland; Belton, Michael J. S. The Galileo spacecraft imaged parts of the western limb and far side of the Moon in December 1990. Ratios of 0.41/0.56 μm filter images from the Solid State Imaging (SSI) experiment provided information on the titanium content of mare deposits; ratios of the 0.76/0.99 μm images indicated 1 μm absorptions associated with Fe2+ in mafic minerals. Mare ages were derived from crater statistics obtained from Lunar Orbiter images. Results on mare compositions in western Oceanus Procellarum and the Humorum basin are consistent with previous Earth-based observations, thus providing confidence in the use of Galileo data to extract compositional information. Mare units in the Grimaldi and Riccioli basins range in age from 3.25 to 3.48 Ga and consist of medium- to medium-high titanium (<4 to 7% TiO2) content lavas. The Schiller-Zucchius basin shows a higher 0.76/0.99 μm ratio than the surrounding highlands, indicating a potentially higher mafic mineral content consistent with previous interpretations that the area includes mare deposits blanketed by highland ejecta and light plains materials. The oldest mare materials in the Orientale basin occur in south-central Mare Orientale and are 3.7 Ga old; youngest mare materials are in Lacus Autumni and are 2.85 Ga old; these units are medium- to medium-high titanium (<4 to 7% TiO2) basalts. Thus, volcanism was active in Orientale for 0.85 Ga, but lavas were relatively constant in composition. Galileo data suggest that Mendel-Rydberg mare is similar to Mare Orientale; cryptomare are present as well. Thus, the mare lavas on the western limb and far side (to 178°E) are remarkably uniform in composition, being generally of medium- to medium-high titanium content and having relatively low 0.76/0.99 μm ratios. This region of the Moon is between two postulated large impact structures, the Procellarum and the South Pole-Aitken basins, and may have a relatively thick crust. In areas underlain by an inferred thinner crust, i.e., zones </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1324517-gemini-planet-imager-observations-au-microscopii-debris-disk-asymmetries-within-one-arcsecond','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1324517-gemini-planet-imager-observations-au-microscopii-debris-disk-asymmetries-within-one-arcsecond">Gemini Planet Imager observations of the AU Microscopii debris disk: Asymmetries within one arcsecond</a> <a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a> Wang, Jason J.; Graham, James R.; Pueyo, Laurent; ... 2015-09-23 We present Gemini Planet Imager (GPI) observations of AU Microscopii, a young M dwarf with an edge-on, dusty debris disk. Integral field spectroscopy and broadband imaging polarimetry were obtained during the commissioning of GPI. In our broadband imaging polarimetry observations, we detect the disk only in total intensity and find asymmetries in the morphology of the disk between the southeast (SE) and northwest (NW) sides. The SE side of the disk exhibits a bump at 1'' (10 AU projected separation) that is three times more vertically extended and three times fainter in peak surface brightness than the NW side atmore » similar separations. This part of the disk is also vertically offset by 69 ± 30 mas to the northeast at 1'' when compared to the established disk midplane and is consistent with prior Atacama Large Millimeter/submillimeter Array and Hubble Space Telescope/Space Telescope Imaging Spectrograph observations. We see hints that the SE bump might be a result of detecting a horizontal sliver feature above the main disk that could be the disk backside. Alternatively, when including the morphology of the NW side, where the disk midplane is offset in the opposite direction ~50 mas between 0farcs4 and 1farcs2, the asymmetries suggest a warp-like feature. Using our integral field spectroscopy data to search for planets, we are 50% complete for ~4 MJup planets at 4 AU. Lastly, we detect a source, resolved only along the disk plane, that could either be a candidate planetary mass companion or a compact clump in the disk.« less </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active">21</li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active">22</li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9463E..0CH','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9463E..0CH">Collaborative real-time motion video analysis by human observer and image exploitation algorithms</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hild, Jutta; Krüger, Wolfgang; Brüstle, Stefan; Trantelle, Patrick; Unmüßig, Gabriel; Heinze, Norbert; Peinsipp-Byma, Elisabeth; Beyerer, Jürgen 2015-05-01 Motion video analysis is a challenging task, especially in real-time applications. In most safety and security critical applications, a human observer is an obligatory part of the overall analysis system. Over the last years, substantial progress has been made in the development of automated image exploitation algorithms. Hence, we investigate how the benefits of automated video analysis can be integrated suitably into the current video exploitation systems. In this paper, a system design is introduced which strives to combine both the qualities of the human observer's perception and the automated algorithms, thus aiming to improve the overall performance of a real-time video analysis system. The system design builds on prior work where we showed the benefits for the human observer by means of a user interface which utilizes the human visual focus of attention revealed by the eye gaze direction for interaction with the image exploitation system; eye tracker-based interaction allows much faster, more convenient, and equally precise moving target acquisition in video images than traditional computer mouse selection. The system design also builds on prior work we did on automated target detection, segmentation, and tracking algorithms. Beside the system design, a first pilot study is presented, where we investigated how the participants (all non-experts in video analysis) performed in initializing an object tracking subsystem by selecting a target for tracking. Preliminary results show that the gaze + key press technique is an effective, efficient, and easy to use interaction technique when performing selection operations on moving targets in videos in order to initialize an object tracking function. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170003779&hterms=hodge&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhodge','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170003779&hterms=hodge&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhodge">The HEXITEC Hard X-Ray Pixelated CdTe Imager for Fast Solar Observations</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Baumgartner, Wayne H.; Christe, Steven D.; Ryan, Daniel; Inglis, Andrew R.; Shih, Albert Y.; Gregory, Kyle; Wilson, Matt; Seller, Paul; Gaskin, Jessica; Wilson-Hodge, Colleen 2016-01-01 There is an increasing demand in solar and astrophysics for high resolution X-ray spectroscopic imaging. Such observations would present ground breaking opportunities to study the poorly understood high energy processes in our solar system and beyond, such as solar flares, X-ray binaries, and active galactic nuclei. However, such observations require a new breed of solid state detectors sensitive to high energy X-rays with fine independent pixels to sub-sample the point spread function (PSF) of the X-ray optics. For solar observations in particular, they must also be capable of handling very high count rates as photon fluxes from solar flares often cause pile up and saturation in present generation detectors. The Rutherford Appleton Laboratory (RAL) has recently developed a new cadmium telluride (CdTe) detector system, called HEXITEC (High Energy X-ray Imaging Technology). It is an 80 x 80 array of 250 micron independent pixels sensitive in the 2-200 keV band and capable of a high full frame read out rate of 10 kHz. HEXITEC provides the smallest independently read out CdTe pixels currently available, and are well matched to the few arcsecond PSF produced by current and next generation hard X-ray focusing optics. NASA's Goddard and Marshall Space Flight Centers are collaborating with RAL to develop these detectors for use on future space borne hard X-ray focusing telescopes. We show the latest results on HEXITEC's imaging capability, energy resolution, high read out rate, and reveal it to be ideal for such future instruments. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018LPICo2063.3139T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018LPICo2063.3139T">Tunable Light-Guide Image Processing Snapshot Spectrometer (TuLIPSS) for Earth and Moon Observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tkaczyk, T. S.; Alexander, D.; Luvall, J. C.; Wang, Y.; Dwight, J. G.; Pawlowsk, M. E.; Howell, B.; Tatum, P. F.; Stoian, R.-I.; Cheng, S.; Daou, A. 2018-02-01 A tunable light-guide image processing snapshot spectrometer (TuLIPSS) for Earth science research and observation is being developed through a NASA instrument incubator project with Rice University and Marshall Space Flight Center. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22522186-molecular-ionized-hydrogen-doradus-imaging-observations','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22522186-molecular-ionized-hydrogen-doradus-imaging-observations">MOLECULAR AND IONIZED HYDROGEN IN 30 DORADUS. I. IMAGING OBSERVATIONS</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Yeh, Sherry C. C.; Seaquist, Ernest R.; Matzner, Christopher D. 2015-07-10 We present the first fully calibrated H{sub 2} 1–0 S(1) image of the entire 30 Doradus nebula. The observations were conducted using the NOAO Extremely Wide-field Infrared Imager (NEWFIRM) on the CTIO 4 m Blanco Telescope. Together with a NEWFIRM Brγ image of 30 Doradus, our data reveal the morphologies of the warm molecular gas and ionized gas in 30 Doradus. The brightest H{sub 2}-emitting area, which extends from the northeast to the southwest of R136, is a photodissociation region (PDR) viewed face-on, while many clumps and pillar features located at the outer shells of 30 Doradus are PDRs viewedmore » edge-on. Based on the morphologies of H{sub 2}, Brγ, CO, and 8 μm emission, the H{sub 2} to Brγ line ratio, and Cloudy models, we find that the H{sub 2} emission is formed inside the PDRs of 30 Doradus, 2–3 pc to the ionization front of the H ii region, in a relatively low-density environment <10{sup 4} cm{sup −3}. Comparisons with Brγ, 8 μm, and CO emission indicate that H{sub 2} emission is due to fluorescence, and provide no evidence for shock excited emission of this line.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=S81-40831&hterms=oil+drilling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Doil%2Bdrilling','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=S81-40831&hterms=oil+drilling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Doil%2Bdrilling">Earth observation photo taken by JPL with the Shuttle Imaging Radar-A</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1981-01-01 Earth observation photo taken by the Jet Propulsion Laboratory (JPL) with the Shuttle Imaging Radar-A (SIR-A). Image of California's coast from Point Concepcion (far left) to Ventura (right). The city of Santa Barbara is visible as a bright region (center). The row of bright spots in the ocean are oil drilling platforms in the Santa Barbara Channel, while the random points of brightness in the channel are vessels. Lakes Cachuma (left) and Casitas (right) are seen as large dark areas. Folded sedimentary rock layers are visible in the Santa Ynez Mountain Range which stretches down the coastline; the stratification terminates at the Santa Ynez fault on the island side of the mountains. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSA11A2130S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSA11A2130S">MOOSE: A Multi-Spectral Observatory Of Sensitive EMCCDs for innovative research in space physics and aeronomy</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Samara, M.; Michell, R. G.; Hampton, D. L.; Trondsen, T. 2012-12-01 The Multi-Spectral Observatory Of Sensitive EMCCDs (MOOSE) consists of 5 imaging systems and is the result of an NSF-funded Major Research Instrumentation project. The main objective of MOOSE is to provide a resource to all members of the scientific community that have interests in imaging low-light-level phenomena, such as aurora, airglow, and meteors. Each imager consists of an Andor DU-888 Electron Multiplying CCD (EMCCD), combined with a telecentric optics section, made by Keo Scientific Ltd., with a selection of available angular fields of view. During the northern hemisphere winter the system is typically based and operated at Poker Flat Research Range in Alaska, but any or all imagers can be shipped anywhere in individual stand-alone cases. We will discuss the main components of the MOOSE project, including the imagers, optics, lenses and filters, as well as the Linux-based control software that enables remote operation. We will also discuss the calibration of the imagers along with the initial deployments and testing done. We are requesting community input regarding operational modes, such as filter and field of view combinations, frame rates, and potentially moving some imagers to other locations, either for tomography or for larger spatial coverage. In addition, given the large volume of auroral image data already available, we are encouraging collaborations for which we will freely distribute the data and any analysis tools already developed. Most significantly, initial science highlights relating to aurora, airglow and meteors will be discussed in the context of the creative and innovative ways that the MOOSE observatory can be used in order to address a new realm of science topics, previously unachievable with traditional single imager systems. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JBO....20j7001M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JBO....20j7001M">Nondestructive observation of teeth post core-space using optical coherence tomography: comparison with microcomputed tomography and live images</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Minamino, Takuya; Mine, Atsushi; Matsumoto, Mariko; Sugawa, Yoshihiko; Kabetani, Tomoshige; Higashi, Mami; Kawaguchi, Asuka; Ohmi, Masato; Awazu, Kunio; Yatani, Hirofumi 2015-10-01 No previous reports have observed inside the root canal using both optical coherence tomography (OCT) and x-ray microcomputed tomography (μCT) for the same sample. The purpose of this study was to clarify both OCT and μCT image properties from observations of the same root canal after resin core build-up treatment. As OCT allows real-time observation of samples, gap formation may be able to be shown in real time. A dual-cure, one-step, self-etch adhesive system bonding agent, and dual-cure resin composite core material were used in root canals in accordance with instructions from the manufacturer. The resulting OCT images were superior for identifying gap formation at the interface, while μCT images were better to grasp the tooth form. Continuous tomographic images from real-time OCT observation allowed successful construction of a video of the resin core build-up procedure. After 10 to 12 s of light curing, a gap with a clear new signal occurred at the root-core material interface, proceeding from the coronal side (6 mm from the cemento-enamel junction) to the apical side of the root. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9416E..06B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9416E..06B">Computational assessment of mammography accreditation phantom images and correlation with human observer analysis</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Barufaldi, Bruno; Lau, Kristen C.; Schiabel, Homero; Maidment, D. A. 2015-03-01 Routine performance of basic test procedures and dose measurements are essential for assuring high quality of mammograms. International guidelines recommend that breast care providers ascertain that mammography systems produce a constant high quality image, using as low a radiation dose as is reasonably achievable. The main purpose of this research is to develop a framework to monitor radiation dose and image quality in a mixed breast screening and diagnostic imaging environment using an automated tracking system. This study presents a module of this framework, consisting of a computerized system to measure the image quality of the American College of Radiology mammography accreditation phantom. The methods developed combine correlation approaches, matched filters, and data mining techniques. These methods have been used to analyze radiological images of the accreditation phantom. The classification of structures of interest is based upon reports produced by four trained readers. As previously reported, human observers demonstrate great variation in their analysis due to the subjectivity of human visual inspection. The software tool was trained with three sets of 60 phantom images in order to generate decision trees using the software WEKA (Waikato Environment for Knowledge Analysis). When tested with 240 images during the classification step, the tool correctly classified 88%, 99%, and 98%, of fibers, speck groups and masses, respectively. The variation between the computer classification and human reading was comparable to the variation between human readers. This computerized system not only automates the quality control procedure in mammography, but also decreases the subjectivity in the expert evaluation of the phantom images. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10567E..2QP','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10567E..2QP">Variable optical filters for earth-observation imaging minispectrometers</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Piegari, A.; Bulir, J.; Krasilnikova, A.; Dami, M.; Harnisch, B. 2017-11-01 Small-dimension, low-mass spectrometers are useful for both Earth observation and planetary missions. A very compact multi-spectral mini-spectrometer that contains no moving parts, can be constructed combining a graded-thickness filter, having a spatially variable narrow-band transmission, to a CCD array detector. The peak wavelength of the transmission filter is moving along one direction of the filter surface, such that each line of a two-dimensional array detector, equipped with this filter, will detect radiation in a different pass band. The spectrum of interest for image spectrometry of the Earth surface is very wide, 400-1000nm. This requirement along with the need of a very small dimension, makes this filter very difficult to manufacture. Preliminary results on metal-dielectric wedge filters, with a gradient of the transmission peak wavelength equal to 60nm/mm, are reported. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018SPIE10577E..0NH','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018SPIE10577E..0NH">Lesion detection performance of cone beam CT images with anatomical background noise: single-slice vs. multi-slice human and model observer study</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Han, Minah; Jang, Hanjoo; Baek, Jongduk 2018-03-01 We investigate lesion detectability and its trends for different noise structures in single-slice and multislice CBCT images with anatomical background noise. Anatomical background noise is modeled using a power law spectrum of breast anatomy. Spherical signal with a 2 mm diameter is used for modeling a lesion. CT projection data are acquired by the forward projection and reconstructed by the Feldkamp-Davis-Kress algorithm. To generate different noise structures, two types of reconstruction filters (Hanning and Ram-Lak weighted ramp filters) are used in the reconstruction, and the transverse and longitudinal planes of reconstructed volume are used for detectability evaluation. To evaluate single-slice images, the central slice, which contains the maximum signal energy, is used. To evaluate multislice images, central nine slices are used. Detectability is evaluated using human and model observer studies. For model observer, channelized Hotelling observer (CHO) with dense difference-of-Gaussian (D-DOG) channels are used. For all noise structures, detectability by a human observer is higher for multislice images than single-slice images, and the degree of detectability increase in multislice images depends on the noise structure. Variation in detectability for different noise structures is reduced in multislice images, but detectability trends are not much different between single-slice and multislice images. The CHO with D-DOG channels predicts detectability by a human observer well for both single-slice and multislice images. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.1951A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.1951A">Initial Observations and Activities of Curiosity's Mars Hand Lens Imager (MAHLI) at the Gale Field Site</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Aileen Yingst, R.; Edgett, Kenneth; MSL Science Team 2013-04-01 the dust and sand obscuration, the observables are unclear —grains 300-500 µm size in the Bathurst Inlet images and 300-500 µm-sized rhombus-shaped crystals in the rock, Jake Matijevic have been observed by some workers. Sand and granules (as well as dust), exhibiting a variety of colors, shapes, and other grain attributes, were deposited on rover hardware during descent. As noted above, sand as well as dust also mantles the rocks observed by MAHLI; in one case the cohesive properties of this material was demonstrated by the presence of a "micro landslide" on a rock named Burwash. At the Rocknest sand shadow, a variety of coarse to very coarse sand grains of differing color, shape, luster, angularity, and roundness were observed, including glassy spheroids and ellipsoids (perhaps formed from impact melt droplets) and clear, translucent grains. The fine to very fine sands sieved (≤ 150 µm) and delivered to the rover's observation tray exhibited at least four distinct grain types, including clear, translucent crystal fragments. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20180001849','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20180001849">The Latest on the Venus Thermospheric General Circulation Model: Capabilities and Simulations</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Brecht, A. S.; Bougher, S. W.; Parkinson, C. D. 2017-01-01 Venus has a complex and dynamic upper atmosphere. This has been observed many times by ground-based, orbiters, probes, and fly-by missions going to other planets. Two over-arching questions are generally asked when examining the Venus upper atmosphere: (1) what creates the complex structure in the atmosphere, and (2) what drives the varying dynamics. A great way to interpret and connect observations to address these questions utilizes numerical modeling; and in the case of the middle and upper atmosphere (above the cloud tops), a 3D hydrodynamic numerical model called the Venus Thermospheric General Circulation Model (VTGCM) can be used. The VTGCM can produce climatological averages of key features in comparison to observations (i.e. nightside temperature, O2 IR nightglow emission). More recently, the VTGCM has been expanded to include new chemical constituents and airglow emissions, as well as new parameterizations to address waves and their impact on the varying global circulation and corresponding airglow distributions. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990013971','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990013971">A Novel, Poly-Etalon, Fabry-Perot for Planetary Research</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kerr, Robert B.; Doe, Richard; Noto, John 1997-01-01 In an effort to develop a mechanically robust, high throughput and solid state spectrometer several liquid crystal Fabry-Perot etalons were constructed. The etalons were tested for spectral response, radiation resistance and optical transmission. The first year of this project was spent developing and understanding the properties of the liquid crystal etalons; in the second year an intensified all-sky imaging system was developed around a pair of LC etalons. The imaging system, developed jointly with SRI International represents a unique brassboard to demonstrate the use of LC etalons as tunable filters. The first set of etalons constructed in year one of this project were tested for spectral response and throughput while etalon surrogates were exposed to proton radiation simulating the exposure of an object in Low Earth Orbit (LEO). The 2" diameter etalons had a measure finesse of approximately 10 and were tunable over five orders. Liquid crystals exposed to proton irradiation showed no signs of damage. In year two two larger diameter (3") etalons were constructed with gaps of 3 and 5 microns. This pair of etalons is for use in a high resolution, all-sky spectral imager. The WATUMI imager system follows the heritage of all sky, narrow band, intensified imagers however it includes two LC Fabry-Perot etalons to provide tunability and the ability to switch wavelengths rapidly, an import consideration in auroral airglow imaging. This work also resulted in two publications and one poster presentation. The instrument will be uniquely capable, with superior throughput and speed, to measure optical airglow of multiple emission lines in harsh conditions. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22685142-clinically-observed-discrepancy-between-image-based-log-based-mlc-positions','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22685142-clinically-observed-discrepancy-between-image-based-log-based-mlc-positions">A clinically observed discrepancy between image-based and log-based MLC positions</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Neal, Brian, E-mail: bpn2p@virginia.edu; Ahmed, Mahmoud; Kathuria, Kunal 2016-06-15 Purpose: To present a clinical case in which real-time intratreatment imaging identified an multileaf collimator (MLC) leaf to be consistently deviating from its programmed and logged position by >1 mm. Methods: An EPID-based exit-fluence dosimetry system designed to prevent gross delivery errors was used to capture cine during treatment images. The author serendipitously visually identified a suspected MLC leaf displacement that was not otherwise detected. The leaf position as recorded on the EPID images was measured and log-files were analyzed for the treatment in question, the prior day’s treatment, and for daily MLC test patterns acquired on those treatment days.more » Additional standard test patterns were used to quantify the leaf position. Results: Whereas the log-file reported no difference between planned and recorded positions, image-based measurements showed the leaf to be 1.3 ± 0.1 mm medial from the planned position. This offset was confirmed with the test pattern irradiations. Conclusions: It has been clinically observed that log-file derived leaf positions can differ from their actual position by >1 mm, and therefore cannot be considered to be the actual leaf positions. This cautions the use of log-based methods for MLC or patient quality assurance without independent confirmation of log integrity. Frequent verification of MLC positions through independent means is a necessary precondition to trust log-file records. Intratreatment EPID imaging provides a method to capture departures from MLC planned positions.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSH33A2035S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSH33A2035S">Radio Imaging Observations of Solar Activity Cycle and Its Anomaly</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Shibasaki, K. 2011-12-01 The 24th solar activity cycle has started and relative sunspot numbers are increasing. However, their rate of increase is rather slow compared to previous cycles. Active region sizes are small, lifetime is short, and big (X-class) flares are rare so far. We study this anomalous situation using data from Nobeyama Radioheliograph (NoRH). Radio imaging observations have been done by NoRH since 1992. Nearly 20 years of daily radio images of the Sun at 17 GHz are used to synthesize a radio butterfly diagram. Due to stable operation of the instrument and a robust calibration method, uniform datasets are available covering the whole period of observation. The radio butterfly diagram shows bright features corresponding to active region belts and their migration toward low latitude as the solar cycle progresses. In the present solar activity cycle (24), increase of radio brightness is delayed and slow. There are also bright features around both poles (polar brightening). Their brightness show solar cycle dependence but peaks around solar minimum. Comparison between the last minimum and the previous one shows decrease of its brightness. This corresponds to weakening of polar magnetic field activity between them. In the northern pole, polar brightening is already weakened in 2011, which means it is close to solar maximum in the northern hemisphere. Southern pole does not show such feature yet. Slow rise of activity in active region belt, weakening of polar activity during the minimum, and large north-south asymmetry in polar activity imply that global solar activity and its synchronization are weakening. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..321L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..321L">Asteroid (4179) Toutatis size determination via optical images observed by the Chang'e-2 probe</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Liu, P.; Huang, J.; Zhao, W.; Wang, X.; Meng, L.; Tang, X. 2014-07-01 This work is a physical and statistical study of the asteroid (4179) Toutatis using the optical images obtained by a solar panel monitor of the Chang'e-2 probe on Dec. 13, 2012 [1]. In the imaging strategy, the camera is focused at infinity. This is specially designed for the probe with its solar panels monitor's principle axis pointing to the relative velocity direction of the probe and Toutatis. The imaging strategy provides a dedicated way to resolve the size by multi-frame optical images. The inherent features of the data are: (1) almost no rotation was recorded because of the 5.41-7.35 Earth-day rotation period and the small amount of elapsed imaging time, only minutes, make the object stay in the images in a fixed position and orientation; (2) the sharpness of the upper left boundary and the vagueness of lower right boundary resulting from the direction of SAP (Sun-Asteroid-Probe angle) cause a varying accuracy in locating points at different parts of Toutatis. A common view is that direct, accurate measurements of asteroid shapes, sizes, and pole positions are now possible for larger asteroids that can be spatially resolved using the Hubble Space Telescope or large ground-based telescopes equipped with adaptive optics. For a quite complex planetary/asteroid probe study, these measurements certainly need continuous validation via a variety of ways [2]. Based on engineering parameters of the probe during the fly-by, the target spatial resolving and measuring procedures are described in the paper. Results estimated are optical perceptible size on the flyby epoch under the solar phase angles during the imaging. It is found that the perceptible size measured using the optical observations and the size derived from the radar observations by Ostro et al.~in 1995 [3], are close to one another. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26158086','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26158086">Implementation of a channelized Hotelling observer model to assess image quality of x-ray angiography systems.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Favazza, Christopher P; Fetterly, Kenneth A; Hangiandreou, Nicholas J; Leng, Shuai; Schueler, Beth A 2015-01-01 Evaluation of flat-panel angiography equipment through conventional image quality metrics is limited by the scope of standard spatial-domain image quality metric(s), such as contrast-to-noise ratio and spatial resolution, or by restricted access to appropriate data to calculate Fourier domain measurements, such as modulation transfer function, noise power spectrum, and detective quantum efficiency. Observer models have been shown capable of overcoming these limitations and are able to comprehensively evaluate medical-imaging systems. We present a spatial domain-based channelized Hotelling observer model to calculate the detectability index (DI) of our different sized disks and compare the performance of different imaging conditions and angiography systems. When appropriate, changes in DIs were compared to expectations based on the classical Rose model of signal detection to assess linearity of the model with quantum signal-to-noise ratio (SNR) theory. For these experiments, the estimated uncertainty of the DIs was less than 3%, allowing for precise comparison of imaging systems or conditions. For most experimental variables, DI changes were linear with expectations based on quantum SNR theory. DIs calculated for the smallest objects demonstrated nonlinearity with quantum SNR theory due to system blur. Two angiography systems with different detector element sizes were shown to perform similarly across the majority of the detection tasks. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170007520&hterms=colors&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcolors','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170007520&hterms=colors&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcolors">An Investigation of Dust Storms Observed with the Mars Color Imager</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Guzewich, Scott D.; Toigo, Anthony D.; Wang, Huiqun 2017-01-01 Daily global imaging by the Mars Color Imager (MARCI) continues the record of the Mars Orbiter Camera (MOC) and has allowed creation of a long-duration record of Martian dust storms. We observe dust storms over the first two Mars years of the MARCI record, including tracking individual storms over multiple sols, as well as tracking the growth and recession of the seasonal polar caps. Using the combined 6 Mars year record of textured dust storms (storms with visible textures on the observed dust cloud tops), we study the relationship between textured dust storm activity and meteorology (as simulated by the MarsWRF general circulation model) and surface properties. We find that textured dust storms preferentially occur in places and seasons with above average surface wind stress. Textured dust storm occurrence also has a modest linear anti-correlation with surface albedo (0.43) and topography (0.40). Lastly, we perform an empirical orthogonal function (EOF) analysis on the distribution of occurrence of textured dust storms and find that over 50 of the variance in textured dust storm activity can be explained by two EOF modes. We associate the first EOF mode with cap-edge storms just before Ls = 180deg and the second EOF mode with flushing dust storms that occur from Ls = 180-210deg and again near Ls = 320deg. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AMT....11..473Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AMT....11..473Z">Retrieval of O2(1Σ) and O2(1Δ) volume emission rates in the mesosphere and lower thermosphere using SCIAMACHY MLT limb scans</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Zarboo, Amirmahdi; Bender, Stefan; Burrows, John P.; Orphal, Johannes; Sinnhuber, Miriam 2018-01-01 We present the retrieved volume emission rates (VERs) from the airglow of both the daytime and twilight O2(1Σ) band and O2(1Δ) band emissions in the mesosphere and lower thermosphere (MLT). The SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) onboard the European Space Agency Envisat satellite observes upwelling radiances in limb-viewing geometry during its special MLT mode over the range 50-150 km. In this study we use the limb observations in the visible (595-811 nm) and near-infrared (1200-1360 nm) bands. We have investigated the daily mean latitudinal distributions and the time series of the retrieved VER in the altitude range from 53 to 149 km. The maximal observed VERs of O2(1Δ) during daytime are typically 1 to 2 orders of magnitude larger than those of O2(1Σ). The latter peaks at around 90 km, whereas the O2(1Δ) emissivity decreases with altitude, with the largest values at the lower edge of the observations (about 53 km). The VER values in the upper mesosphere (above 80 km) are found to depend on the position of the sun, with pronounced high values occurring during summer for O2(1Δ). O2(1Σ) emissions show additional high values at polar latitudes during winter and spring. These additional high values are presumably related to the downwelling of atomic oxygen after large sudden stratospheric warmings (SSWs). Accurate measurements of the O2(1Σ) and O2(1Δ) airglow, provided that the mechanism of their production is understood, yield valuable information about both the chemistry and dynamics in the MLT. For example, they can be used to infer the amounts and distribution of ozone, solar heating rates, and temperature in the MLT. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JKPS...65..786K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JKPS...65..786K">A comparison of FUV dayglows measured by STSAT-1/FIMS with the AURIC model in a geomagnetic quiet condition</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kam, Hosik; Kim, Yong Ha; Hong, Jun-Seok; Lee, Joon-Chan; Choi, Yeon-Ju; Min, Kyung Wook 2014-09-01 The Korea scientific microsatellite, STSAT-1 (Science and Technology Satellite-1), was launched in 2003 and observed far ultraviolet (FUV) airglow from the upper atmosphere with a Far-ultraviolet IMaging Spectrograph (FIMS) at an altitude of 690 km. The FIMS consists of a dual-band imaging spectrograph of 900-1150 Å (S-band) and 1340-1715 Å (L-band). Limb scanning observations were performed only at the S-band, resulting in intensity profiles of OI 989 Å, OI 1026 Å, NII 1085 Å and NI 1134 Å emission lines near the horizon. We compare these emission intensities with those computed by using a theoretical model, the AURIC (Atmospheric Ultraviolet Radiance Integrated Code). The intensities of the OI 1026 Å, NII 1085 Å and NI 1134 Å emissions measured by using the FIMS are overall consistent with the values computed by using AURIC under the thermospheric and solar activity conditions on August 6, 1984, which is close to the FIMS's observation condition. We find that the FIMS dayglow intensity profiles match reasonably well with AURIC intensity profiles for the MSIS90 oxygen atom density profiles within factors of 0.5 and 2. However, the FIMS intensities of the OI 989 Å line are about 2 ˜ 4 times stronger than the AURIC intensities, which is expected because AURIC does not properly simulate resonance scattering of airglow and solar photons at 989 Å by atomic oxygen in the thermosphere. We also find that the maximum tangential altitudes of the oxygen bearing dayglows (OI 989 Å, OI 1026 Å) are higher than those of the nitrogen-bearing dayglows (NII 1085 Å, NI 1134 Å), which is confirmed by using AURIC model calculations. This is expected because the oxygen atoms are distributed at higher altitudes in the thermosphere than the nitrogen molecules. Validations of the qualities of both the FIMS instrument and the AURIC model indicate that AURIC should be updated with improved thermospheric models and with measured solar FUV spectra for better agreement with the </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active">22</li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active">23</li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRE..115.9002V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRE..115.9002V">Observations from the High Resolution Imaging Science Experiment (HiRISE): Martian dust devils in Gusev and Russell craters</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Verba, Circe A.; Geissler, Paul E.; Titus, Timothy N.; Waller, Devin 2010-09-01 Two areas targeted for repeated imaging by detailed High Resolution Imaging Science Experiment (HiRISE) observations allow us to examine morphological differences and monitor seasonal variations of Martian dust devil tracks at two quite different locations. Russell crater (53.3°S, 12.9°E) is regularly imaged to study seasonal processes including deposition and sublimation of CO2 frost. Gusev crater (14.6°S, 175.4°E) has been frequently imaged in support of the Mars Exploration Rover mission. Gusev crater provides the first opportunity to compare “ground truth” orbital observations of dust devil tracks to surface observations of active dust plumes. Orbital observations show that dust devil tracks are rare, forming at a rate <1/110 that of the occurrence of active dust plumes estimated from Spirit's surface observations. Furthermore, the tracks observed from orbit are wider than typical plume diameters observed by Spirit. We conclude that the tracks in Gusev are primarily formed by rare, large dust devils. Smaller dust devils fail to leave tracks that are visible from orbit, perhaps because of limited surface excavation depths. Russell crater displays more frequent, smaller sinuous tracks than Gusev. This may be due to the thin dust cover in Russell, allowing smaller dust devils to penetrate through the bright dust layer and leave conspicuous tracks. The start of the dust devil season and peak activity are delayed in Russell in comparison to Gusev, likely because of its more southerly location. Dust devils in both sites travel in directions consistent with general circulation model (GCM)-predicted winds, confirming a laboratory-derived approach to determining dust devil travel directions based on track morphology. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9143E..2BZ','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9143E..2BZ">BATMAN flies: a compact spectro-imager for space observation</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Zamkotsian, Frederic; Ilbert, Olivier; Zoubian, Julien; Delsanti, Audrey; Boissier, Samuel; Lancon, Ariane 2014-08-01 BATMAN flies is a compact spectro-imager based on MOEMS for generating reconfigurable slit masks, and feeding two arms in parallel. The FOV is 25 x 12 arcmin2 for a 1m telescope, in infrared (0.85-1.7μm) and 500-1000 spectral resolution. Unique science cases for Space Observation are reachable with this deep spectroscopic multi-survey instrument: deep survey of high-z galaxies down to H=25 on 5 deg2 with continuum detection and all z>7 candidates at H=26.2 over 5 deg2; deep survey of young stellar clusters in nearby galaxies; deep survey of the Kuiper Belt of ALL known objects down to H=22. Pathfinder towards BATMAN in space is already running with ground-based demonstrators. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970026745','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970026745">Nocturnal Observations of the Semidiurnal Tide at a Midlatitude Site</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Niciejewski, R. J.; Killeen, T. L. 1995-01-01 Fabry-Perot interferometer observations of the mesospheric hydroxyl emission and the lower thermospheric OI (5577A) emission have been conducted from an airglow observatory at a dark field site in southeastern Michigan for the past several years. The primary functions of the observatory are to provide a database for correlative observations with the UARS satellite and to provide a synoptic measurement program for the coupling energetics and dynamics of atmospheric regions effort, An intensive operational effort between May 1993 and July 1994 has resulted in a substantial data set from which neutral winds have been determined from the bifilter acquisition sequence. A 'best fit' analysis in the least squares sense of the simultaneous measurements of the neutral winds to a 12-hour periodicity has provided amplitude and phase parameters for the semidiurnal tide as well as a measure of the mean wind. The measured tidal amplitude is greater at the higher altitude, though the seasonal behavior at both altitudes is similar with greater amplitudes during August/September and April/May. Both meridional and zonal wind components are consistent with a semidiurnal tidal description during the entire observational sequence except for the May to July 1993 period. The mean winds show annual variation in the meridional flow, being equatorward from May to October and poleward during the winter. The zonal flow is primarily eastward during the entire observational window with higher speed flows during May/June at the higher attitude and June/July at the lower altitude. A comparison with a semidiurnal tidal model indicates that the measured tidal amplitudes are a factor of 2 times greater, while the phases show similar equinoctial transitions. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017OcDyn..67..875D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017OcDyn..67..875D">Exploring image data assimilation in the prospect of high-resolution satellite oceanic observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Durán Moro, Marina; Brankart, Jean-Michel; Brasseur, Pierre; Verron, Jacques 2017-07-01 Satellite sensors increasingly provide high-resolution (HR) observations of the ocean. They supply observations of sea surface height (SSH) and of tracers of the dynamics such as sea surface salinity (SSS) and sea surface temperature (SST). In particular, the Surface Water Ocean Topography (SWOT) mission will provide measurements of the surface ocean topography at very high-resolution (HR) delivering unprecedented information on the meso-scale and submeso-scale dynamics. This study investigates the feasibility to use these measurements to reconstruct meso-scale features simulated by numerical models, in particular on the vertical dimension. A methodology to reconstruct three-dimensional (3D) multivariate meso-scale scenes is developed by using a HR numerical model of the Solomon Sea region. An inverse problem is defined in the framework of a twin experiment where synthetic observations are used. A true state is chosen among the 3D multivariate states which is considered as a reference state. In order to correct a first guess of this true state, a two-step analysis is carried out. A probability distribution of the first guess is defined and updated at each step of the analysis: (i) the first step applies the analysis scheme of a reduced-order Kalman filter to update the first guess probability distribution using SSH observation; (ii) the second step minimizes a cost function using observations of HR image structure and a new probability distribution is estimated. The analysis is extended to the vertical dimension using 3D multivariate empirical orthogonal functions (EOFs) and the probabilistic approach allows the update of the probability distribution through the two-step analysis. Experiments show that the proposed technique succeeds in correcting a multivariate state using meso-scale and submeso-scale information contained in HR SSH and image structure observations. It also demonstrates how the surface information can be used to reconstruct the ocean state below </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840049457&hterms=astronomia+espacio&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dastronomia%2By%2Bespacio','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840049457&hterms=astronomia+espacio&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dastronomia%2By%2Bespacio">Microwave, soft and hard X-ray imaging observations of two solar flares</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kundu, M. R.; Erskine, F. T.; Schmahl, E. J.; Machado, M. E.; Rovira, M. G. 1984-01-01 A set of microwave and hard X-ray observations of two flares observed simultaneously with the Very Large Array (VLA) and the Solar Maximum Mission Hard X-ray Imaging Spectrometer (SMM-HXIS) are presented. The LVA was used at 6 cm to map the slowly varying and burst components in three neighboring solar active regions (Boulder Nos. 2522, 2530, and 2519) from approximately 14:00 UT until 01:00 UT on June 24-25, 1980. Six microwave bursts less than 30 sfu were observed, and for the strongest of these, two-dimensional 'snapshot' (10 s) maps with spatial resolution of 5 in. were synthesized. HXIS data show clear interconnections between regions 2522 and 2530. The X-ray observations present a global picture of flaring activity, while the VLA data show the complexity of the small magnetic structures associated with the impulsive phase phenomena. It is seen that energy release did not occur in a single isolated magnetic structure, but over a large area of intermingled loop structures. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=GL-2002-001170&hterms=cosmology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dcosmology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=GL-2002-001170&hterms=cosmology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dcosmology">False-color images from observations by the Supernova Cosmology Project of one of the two most dista</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 2002-01-01 TFalse-color images from observations by the Supernova Cosmology Project of one of the two most distant spectroscopically confirmed supernova. From the left: the first two images, from the Cerro Tololo Interamerican Observatory 4-meter telescope, show a small region of sky just before and just after the the appearance of a type-Ia supernova that exploded when the universe was about half its present age. The third image shows the same supernova as observed with the Hubble Space Telescope. This much sharper picture allows a much better measurement of the apparent brightness and hence the distance of this supernova. Because their intrinsic brightness is predictable, such supernovae help to determine the deceleration, and so the eventual fate, of the universe. Credit: Perlmutter et al., The Supernova Cosmology Project </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10136E..0MB','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10136E..0MB">Signal template generation from acquired mammographic images for the non-prewhitening model observer with eye-filter</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Balta, Christiana; Bouwman, Ramona W.; Sechopoulos, Ioannis; Broeders, Mireille J. M.; Karssemeijer, Nico; van Engen, Ruben E.; Veldkamp, Wouter J. H. 2017-03-01 Model observers (MOs) are being investigated for image quality assessment in full-field digital mammography (FFDM). Signal templates for the non-prewhitening MO with eye filter (NPWE) were formed using acquired FFDM images. A signal template was generated from acquired images by averaging multiple exposures resulting in a low noise signal template. Noise elimination while preserving the signal was investigated and a methodology which results in a noise-free template is proposed. In order to deal with signal location uncertainty, template shifting was implemented. The procedure to generate the template was evaluated on images of an anthropomorphic breast phantom containing microcalcification-related signals. Optimal reduction of the background noise was achieved without changing the signal. Based on a validation study in simulated images, the difference (bias) in MO performance from the ground truth signal was calculated and found to be <1%. As template generation is a building stone of the entire image quality assessment framework, the proposed method to construct templates from acquired images facilitates the use of the NPWE MO in acquired images. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.P11B1271S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.P11B1271S">Latitudinal Variations In Vertical Cloud Structure Of Jupiter As Determined By Ground- based Observation With Multispectral Imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sato, T.; Kasaba, Y.; Takahashi, Y.; Murata, I.; Uno, T.; Tokimasa, N.; Sakamoto, M. 2008-12-01 We conducted ground-based observation of Jupiter with the liquid crystal tunable filter (LCTF) and EM-CCD camera in two methane absorption bands (700-757nm, 872-950nm at 3 nm step: total of 47 wavelengths) to derive detailed Jupiter's vertical cloud structure. The 2-meter reflector telescope at Nishi-Harima astronomical observatory in Japan was used for our observation on 26-30 May, 2008. After a series of image processing (composition of high quality images in each wavelength and geometry calibration), we converted observed intensity to absolute reflectivity at each pixel using standard star. As a result, we acquired Jupiter's data cubes with high-spatial resolution (about 1") and narrow band imaging (typically 7nm) in each methane absorption band by superimposing 30 Jupiter's images obtained in short exposure time (50 ms per one image). These data sets enable us to probe different altitudes of Jupiter from 100 mbar down to 1bar level with higher vertical resolution than using convectional interference filters. To interpret observed center-limb profiles, we developed radiative transfer code based on layer adding doubling algorithm to treat multiple scattering of solar light theoretically and extracted information on aerosol altitudes and optical properties using two-cloud model. First, we fit 5 different profiles simultaneously in continuum data (745-757 nm) to retrieve information on optical thickness of haze and single scattering albedo of cloud. Second, we fit 15 different profiles around 727nm methane absorption band and 13 different profiles around 890 nm methane absorption band to retrieve information on the aerosol altitude location and optical thickness of cloud. In this presentation, we present the results of these modeling simulations and discuss the latitudinal variations of Jupiter's vertical cloud structure. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM21E..07G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM21E..07G">Ultraviolet Observations of the Earth and Moon during the Juno Flyby</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gladstone, R.; Versteeg, M. H.; Davis, M.; Greathouse, T. K.; Gerard, J. M.; Grodent, D. C.; Bonfond, B. 2013-12-01 We present the initial results from Juno-UVS observations of the Earth and Moon obtained during the flyby of the Juno spacecraft on 9 October 2013. Juno-UVS is an imaging spectrograph with a bandpass of 70<λ<205 nm. This wavelength range includes all important ultraviolet (UV) emissions from the H2 bands and the H Lyman series which are produced in Jupiter's auroras, and also the absorption signatures of aurorally-produced hydrocarbons. The Juno-UVS instrument consists of two separate sections: a dedicated telescope/spectrograph assembly and a vault electronics box. The telescope/spectrograph assembly contains a telescope which feeds a 0.15-m Rowland circle spectrograph. The telescope has a 4 x 4 cm2 input aperture and uses an off-axis parabolic (OAP) primary mirror. A flat scan mirror situated at the front end of the telescope (used to observe at up to ×30° perpendicular to the Juno spin plane) directs incoming light to the OAP. The light is focused onto the spectrograph entrance slit, which has a 'dog-bone' shape 7.2° long, in three sections of 0.2°, 0.025°, and 0.2° width (as projected onto the sky). Light entering the slit is dispersed by a toroidal grating which focuses UV light onto a curved microchannel plate cross delay line detector with a solar blind UV-sensitive CsI photocathode, which makes up the instrument's focal plane. Tantalum surrounds the detector assembly to shield it from high-energy electrons. The detector electronics are located behind the detector. All other electronics are located in a box inside Juno's spacecraft vault, including redundant low-voltage and high-voltage power supplies, command and data handling electronics, heater/actuator electronics, scan mirror electronics, and event processing electronics. The purpose of Juno-UVS is to remotely sense Jupiter's auroral morphology and brightness to provide context for in situ measurements by Juno's particle instruments. The recent Earth flyby provided an opportunity to: 1) use </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4478895','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4478895">Implementation of a channelized Hotelling observer model to assess image quality of x-ray angiography systems</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Favazza, Christopher P.; Fetterly, Kenneth A.; Hangiandreou, Nicholas J.; Leng, Shuai; Schueler, Beth A. 2015-01-01 Abstract. Evaluation of flat-panel angiography equipment through conventional image quality metrics is limited by the scope of standard spatial-domain image quality metric(s), such as contrast-to-noise ratio and spatial resolution, or by restricted access to appropriate data to calculate Fourier domain measurements, such as modulation transfer function, noise power spectrum, and detective quantum efficiency. Observer models have been shown capable of overcoming these limitations and are able to comprehensively evaluate medical-imaging systems. We present a spatial domain-based channelized Hotelling observer model to calculate the detectability index (DI) of our different sized disks and compare the performance of different imaging conditions and angiography systems. When appropriate, changes in DIs were compared to expectations based on the classical Rose model of signal detection to assess linearity of the model with quantum signal-to-noise ratio (SNR) theory. For these experiments, the estimated uncertainty of the DIs was less than 3%, allowing for precise comparison of imaging systems or conditions. For most experimental variables, DI changes were linear with expectations based on quantum SNR theory. DIs calculated for the smallest objects demonstrated nonlinearity with quantum SNR theory due to system blur. Two angiography systems with different detector element sizes were shown to perform similarly across the majority of the detection tasks. PMID:26158086 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29674564','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29674564">Observing the cell in its native state: Imaging subcellular dynamics in multicellular organisms.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Liu, Tsung-Li; Upadhyayula, Srigokul; Milkie, Daniel E; Singh, Ved; Wang, Kai; Swinburne, Ian A; Mosaliganti, Kishore R; Collins, Zach M; Hiscock, Tom W; Shea, Jamien; Kohrman, Abraham Q; Medwig, Taylor N; Dambournet, Daphne; Forster, Ryan; Cunniff, Brian; Ruan, Yuan; Yashiro, Hanako; Scholpp, Steffen; Meyerowitz, Elliot M; Hockemeyer, Dirk; Drubin, David G; Martin, Benjamin L; Matus, David Q; Koyama, Minoru; Megason, Sean G; Kirchhausen, Tom; Betzig, Eric 2018-04-20 True physiological imaging of subcellular dynamics requires studying cells within their parent organisms, where all the environmental cues that drive gene expression, and hence the phenotypes that we actually observe, are present. A complete understanding also requires volumetric imaging of the cell and its surroundings at high spatiotemporal resolution, without inducing undue stress on either. We combined lattice light-sheet microscopy with adaptive optics to achieve, across large multicellular volumes, noninvasive aberration-free imaging of subcellular processes, including endocytosis, organelle remodeling during mitosis, and the migration of axons, immune cells, and metastatic cancer cells in vivo. The technology reveals the phenotypic diversity within cells across different organisms and developmental stages and may offer insights into how cells harness their intrinsic variability to adapt to different physiological environments. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6921407-imaging-observations-sn1987a-gamma-ray-energies','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6921407-imaging-observations-sn1987a-gamma-ray-energies">Imaging observations of SN1987A at gamma-ray energies</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Cook, W.R.; Palmer, D.M.; Prince, T.A. 1988-09-25 The Caltech imaging ..gamma..-ray telescope was launched by balloon from Alice Springs, NT, Australia for observations of SN1987A during the period 18.60--18.87 November 1987 UT. The preliminary results presented here are derived from 8200 seconds of instrument livetime on the supernova and 2500 seconds on the Crab Nebula and pulsar at a float altitude of 37 km. We have obtained the first images of the SN1987A region at ..gamma..-ray energies confirming that the bulk of the ..gamma..-ray emission comes from the supernova and not from LMC X-1. A count excess is detected between 300 and 1300 keV from the directionmore » of the supernova, one third of which comes from energy bands of width 80 and 92 keV centered on 847 and 1238 keV, respectively. The excess can be interpreted as a line photon flux plus scattered photon continuum from the radioactive decay of /sup 56/Co synthesized in the supernova explosion. We compare our data to recent predictions and find it to be consistent with models invoking moderate mixing of core material into the envelope.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988AIPC..170...60C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988AIPC..170...60C">Imaging observations of SN1987A at gamma-ray energies</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Cook, W. R.; Palmer, D. M.; Prince, T. A.; Schindler, S. M.; Starr, C. H.; Stone, E. C. 1988-09-01 The Caltech imaging γ-ray telescope was launched by balloon from Alice Springs, NT, Australia for observations of SN1987A during the period 18.60-18.87 November 1987 UT. The preliminary results presented here are derived from 8200 seconds of instrument livetime on the supernova and 2500 seconds on the Crab Nebula and pulsar at a float altitude of 37 km. We have obtained the first images of the SN1987A region at γ-ray energies confirming that the bulk of the γ-ray emission comes from the supernova and not from LMC X-1. A count excess is detected between 300 and 1300 keV from the direction of the supernova, one third of which comes from energy bands of width 80 and 92 keV centered on 847 and 1238 keV, respectively. The excess can be interpreted as a line photon flux plus scattered photon continuum from the radioactive decay of 56Co synthesized in the supernova explosion. We compare our data to recent predictions and find it to be consistent with models invoking moderate mixing of core material into the envelope. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020068003&hterms=cosmic+microwave+background&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcosmic%2Bmicrowave%2Bbackground','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020068003&hterms=cosmic+microwave+background&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcosmic%2Bmicrowave%2Bbackground">The Anisotropy of the Microwave Background to l=3500: Mosaic Observations with the Cosmic Background Imager</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Pearson, T. J.; Mason, B. S.; Readhead, A. C. S.; Shepherd, M. C.; Sievers, J. L.; Udomprasert, P. S.; Cartwright, J. K.; Farmer, A. J.; Padin, S.; Myers, S. T.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20020068003'); toggleEditAbsImage('author_20020068003_show'); toggleEditAbsImage('author_20020068003_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20020068003_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20020068003_hide"> 2002-01-01 Using the Cosmic Background Imager, a 13-element interferometer array operating in the 26-36 GHz frequency band, we have observed 40 deg (sup 2) of sky in three pairs of fields, each approximately 145 feet x 165 feet, using overlapping pointings: (mosaicing). We present images and power spectra of the cosmic microwave background radiation in these mosaic fields. We remove ground radiation and other low-level contaminating signals by differencing matched observations of the fields in each pair. The primary foreground contamination is due to point sources (radio galaxies and quasars). We have subtracted the strongest sources from the data using higher-resolution measurements, and we have projected out the response to other sources of known position in the power-spectrum analysis. The images show features on scales approximately 6 feet-15 feet, corresponding to masses approximately 5-80 x 10(exp 14) solar mass at the surface of last scattering, which are likely to be the seeds of clusters of galaxies. The power spectrum estimates have a resolution delta l approximately 200 and are consistent with earlier results in the multipole range l approximately less than 1000. The power spectrum is detected with high signal-to-noise ratio in the range 300 approximately less than l approximately less than 1700. For 1700 approximately less than l approximately less than 3000 the observations are consistent with the results from more sensitive CBI deep-field observations. The results agree with the extrapolation of cosmological models fitted to observations at lower l, and show the predicted drop at high l (the "damping tail"). </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/962373','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/962373">Detection of facilities in satellite imagery using semi-supervised image classification and auxiliary contextual observables</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Harvey, Neal R; Ruggiero, Christy E; Pawley, Norma H 2009-01-01 Detecting complex targets, such as facilities, in commercially available satellite imagery is a difficult problem that human analysts try to solve by applying world knowledge. Often there are known observables that can be extracted by pixel-level feature detectors that can assist in the facility detection process. Individually, each of these observables is not sufficient for an accurate and reliable detection, but in combination, these auxiliary observables may provide sufficient context for detection by a machine learning algorithm. We describe an approach for automatic detection of facilities that uses an automated feature extraction algorithm to extract auxiliary observables, and a semi-supervisedmore » assisted target recognition algorithm to then identify facilities of interest. We illustrate the approach using an example of finding schools in Quickbird image data of Albuquerque, New Mexico. We use Los Alamos National Laboratory's Genie Pro automated feature extraction algorithm to find a set of auxiliary features that should be useful in the search for schools, such as parking lots, large buildings, sports fields and residential areas and then combine these features using Genie Pro's assisted target recognition algorithm to learn a classifier that finds schools in the image data.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.2801K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.2801K">Seasonal variation of upper mesospheric temperatures from the OH and O2 nightglow over King Sejong Station, Antarctica</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kim, J.-H.; Kim, Y. H.; Moon, B.-K.; Chung, J.-K.; Won, Y.-I. A spectral airglow temperature imager SATI was operated at King Sejong Station 62 22 r S 301 2 r E Korea Antarctic Research Station during a period of 2002 - 2005 Rotational temperatures from the OH 6-2 and O 2 0-1 band airglow were obtained for more than 600 nights during the 4 year operation Both the OH and O 2 temperatures show similar seasonal variations which change significantly year by year A maximum temperature occurred early May in 2003 and 2004 whereas two maxima appeared in April and August in 2002 The 2005 data show only a broad and weak maximum during months of April and May The data also show oscillations with periods of hours that seem to relate to tides and gravity waves and fluctuations with timescales of days that could be due to planetary waves Detailed analysis will be performed to the data set to identify major atmospheric oscillations or variation over hours days and seasons </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3465370','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3465370">Suomi satellite brings to light a unique frontier of nighttime environmental sensing capabilities</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Miller, Steven D.; Mills, Stephen P.; Elvidge, Christopher D.; Lindsey, Daniel T.; Lee, Thomas F.; Hawkins, Jeffrey D. 2012-01-01 Most environmental satellite radiometers use solar reflectance information when it is available during the day but must resort at night to emission signals from infrared bands, which offer poor sensitivity to low-level clouds and surface features. A few sensors can take advantage of moonlight, but the inconsistent availability of the lunar source limits measurement utility. Here we show that the Day/Night Band (DNB) low-light visible sensor on the recently launched Suomi National Polar-orbiting Partnership (NPP) satellite has the unique ability to image cloud and surface features by way of reflected airglow, starlight, and zodiacal light illumination. Examples collected during new moon reveal not only meteorological and surface features, but also the direct emission of airglow structures in the mesosphere, including expansive regions of diffuse glow and wave patterns forced by tropospheric convection. The ability to leverage diffuse illumination sources for nocturnal environmental sensing applications extends the advantages of visible-light information to moonless nights. PMID:22984179 </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ApJ...845...30M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ApJ...845...30M">Structure and Dynamics of Cool Flare Loops Observed by the Interface Region Imaging Spectrograph</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mikuła, K.; Heinzel, P.; Liu, W.; Berlicki, A. 2017-08-01 Flare loops were well observed with the Interface Region Imaging Spectrograph (IRIS) during the gradual phase of two solar flares on 2014 March 29 and 2015 June 22. Cool flare loops are visible in various spectral lines formed at chromospheric and transition-region temperatures and exhibit large downflows which correspond to the standard scenario. The principal aim of this work is to analyze the structure and dynamics of cool flare loops observed in Mg II lines. Synthetic profiles of the Mg II h line are computed using the classical cloud model and assuming a uniform background intensity. In this paper, we study novel IRIS NUV observations of such loops in Mg II h and k lines and also show the behavior of hotter lines detected in the FUV channel. We obtained the spatial evolution of the velocities: near the loop top, the flow velocities are small and they are increasing toward the loop legs. Moreover, from slit-jaw image (SJI) movies, we observe some plasma upflows into the loops, which are also detectable in Mg II spectra. The brightness of the loops systematically decreases with increasing flow velocity, and we ascribe this to the effect of Doppler dimming, which works for Mg II lines. Emission profiles of Mg II were found to be extremely broad, and we explain this through the large unresolved non-thermal motions. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22663283-structure-dynamics-cool-flare-loops-observed-interface-region-imaging-spectrograph','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22663283-structure-dynamics-cool-flare-loops-observed-interface-region-imaging-spectrograph">Structure and Dynamics of Cool Flare Loops Observed by the Interface Region Imaging Spectrograph</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Mikuła, K.; Berlicki, A.; Heinzel, P. Flare loops were well observed with the Interface Region Imaging Spectrograph ( IRIS ) during the gradual phase of two solar flares on 2014 March 29 and 2015 June 22. Cool flare loops are visible in various spectral lines formed at chromospheric and transition-region temperatures and exhibit large downflows which correspond to the standard scenario. The principal aim of this work is to analyze the structure and dynamics of cool flare loops observed in Mg ii lines. Synthetic profiles of the Mg ii h line are computed using the classical cloud model and assuming a uniform background intensity. In thismore » paper, we study novel IRIS NUV observations of such loops in Mg ii h and k lines and also show the behavior of hotter lines detected in the FUV channel. We obtained the spatial evolution of the velocities: near the loop top, the flow velocities are small and they are increasing toward the loop legs. Moreover, from slit-jaw image (SJI) movies, we observe some plasma upflows into the loops, which are also detectable in Mg ii spectra. The brightness of the loops systematically decreases with increasing flow velocity, and we ascribe this to the effect of Doppler dimming, which works for Mg ii lines. Emission profiles of Mg ii were found to be extremely broad, and we explain this through the large unresolved non-thermal motions.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....8673E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....8673E">Science objectives and observing strategy for the OMEGA imaging spectrometer on Mars-Express</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Erard, S.; Bibring, J.-P.; Drossart, P.; Forget, F.; Schmitt, B.; OMEGA Team 2003-04-01 The science objectives of OMEGA, which were first defined at the time of instruments selection for Mars-Express, were recently updated to integrate new results from MGS and Odyssey concerning three main fields: Martian surface and atmosphere, and polar processes. Thematic categories of observations are derived from the scientific objectives whenever spectral observations from OMEGA are expected to provide insights to Mars present situation and evolution. Targets within these categories are selected on the basis of their expected usefulness, which is related to their intrinsic properties and to the instrument capabilities. The whole surface will be mapped at low resolution (~5 km/pixel) in the course of the nominal mission, and possibly routinely at very coarse resolution to monitor time-varying processes from apocenter. However, only 5% of the surface can be observed at high resolution (up to 350 m/pixel) owing to constraints on telemetry rate. HR targets are therefore selected on the basis of telemetry constraints, orbital parameters, observing opportunities (visibility under given conditions), and spacecraft functionalities (e.g., depointing capacity), then prioritized within each category according to the probability to perform significant observations with OMEGA (in many situations, according to the estimated dust coverage). Target selection is performed interactively between OMEGA co-Is, in close contact with teams from other MEx experiments (mostly HRSC, PFS and Spicam) and other missions (e.g., MER and MRO). Most HR surface targets are selected on the basis of deep examination of Viking, THEMIS, and MOC HR images. Other surface targets include areas presenting unusual spectral properties in previous observations, or suspected to exhibit signatures of hydrothermal activity. Proposed landing sites and suggested source areas for the SNC meteorites are also included. Atmospheric/polar objectives more often translate as particular observing modes, sometimes at HR </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active">23</li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active">24</li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22521637-active-region-bright-grains-observed-transition-region-imaging-channels-iris','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22521637-active-region-bright-grains-observed-transition-region-imaging-channels-iris">ON THE ACTIVE REGION BRIGHT GRAINS OBSERVED IN THE TRANSITION REGION IMAGING CHANNELS OF IRIS</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Skogsrud, H.; Voort, L. Rouppe van der; Pontieu, B. De The Interface Region Imaging Spectrograph (IRIS) provides spectroscopy and narrow band slit-jaw (SJI) imaging of the solar chromosphere and transition region at unprecedented spatial and temporal resolutions. Combined with high-resolution context spectral imaging of the photosphere and chromosphere as provided by the Swedish 1 m Solar Telescope (SST), we can now effectively trace dynamic phenomena through large parts of the solar atmosphere in both space and time. IRIS SJI 1400 images from active regions, which primarily sample the transition region with the Si iv 1394 and 1403 Å lines, reveal ubiquitous bright “grains” which are short-lived (two to five minute)more » bright roundish small patches of sizes 0.″5–1.″7 that generally move limbward with velocities up to about 30 km s{sup −1}. In this paper, we show that many bright grains are the result of chromospheric shocks impacting the transition region. These shocks are associated with dynamic fibrils (DFs), most commonly observed in Hα. We find that the grains show the strongest emission in the ascending phase of the DF, that the emission is strongest toward the top of the DF, and that the grains correspond to a blueshift and broadening of the Si iv lines. We note that the SJI 1400 grains can also be observed in the SJI 1330 channel which is dominated by C ii lines. Our observations show that a significant part of the active region transition region dynamics is driven from the chromosphere below rather than from coronal activity above. We conclude that the shocks that drive DFs also play an important role in the heating of the upper chromosphere and lower transition region.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982STIN...8318976F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982STIN...8318976F">Application of X-ray television image system to observation in solid rocket motor</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fujiwara, T.; Ito, K.; Tanemura, T.; Shimizu, M.; Godai, T. The X-ray television image system is used to observe the solid propellant burning surface during rocket motor operation as well as to inspect defects in solid rocket motors in a real time manner. This system can test 200 mm diameter dummy propellant rocket motors with under 2 percent discriminative capacity. Viewing of a 50 mm diameter internal-burning rocket motor, propellant burning surface time transition and propellant burning process of the surroundings of artificial defects were satisfactorily observed. The system was demonstrated to be effective for nondestructive testing and combustion research of solid rocket motors. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/21301646-deep-band-imaging-goods-south-observations-data-reduction-first-results','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/21301646-deep-band-imaging-goods-south-observations-data-reduction-first-results">DEEP U BAND AND R IMAGING OF GOODS-SOUTH: OBSERVATIONS, DATA REDUCTION AND FIRST RESULTS ,</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Nonino, M.; Cristiani, S.; Vanzella, E. 2009-08-01 We present deep imaging in the U band covering an area of 630 arcmin{sup 2} centered on the southern field of the Great Observatories Origins Deep Survey (GOODS). The data were obtained with the VIMOS instrument at the European Southern Observatory (ESO) Very Large Telescope. The final images reach a magnitude limit U {sub lim} {approx} 29.8 (AB, 1{sigma}, in a 1'' radius aperture), and have good image quality, with full width at half-maximum {approx}0.''8. They are significantly deeper than previous U-band images available for the GOODS fields, and better match the sensitivity of other multiwavelength GOODS photometry. The deepermore » U-band data yield significantly improved photometric redshifts, especially in key redshift ranges such as 2 < z < 4, and deeper color-selected galaxy samples, e.g., Lyman break galaxies at z {approx} 3. We also present the co-addition of archival ESO VIMOS R-band data, with R {sub lim} {approx} 29 (AB, 1{sigma}, 1'' radius aperture), and image quality {approx}0.''75. We discuss the strategies for the observations and data reduction, and present the first results from the analysis of the co-added images.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ApJ...749L..23D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ApJ...749L..23D">First Science Observations with SOFIA/FORCAST: 6-37 μm Imaging of Orion BN/KL</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> De Buizer, James M.; Morris, Mark R.; Becklin, E. E.; Zinnecker, Hans; Herter, Terry L.; Adams, Joseph D.; Shuping, Ralph Y.; Vacca, William D. 2012-04-01 The Becklin-Neugebauer/Kleinmann-Low (BN/KL) region of the Orion Nebula is the nearest region of high-mass star formation in our galaxy. As such, it has been the subject of intense investigation at a variety of wavelengths, which have revealed it to be brightest in the infrared to submillimeter wavelength regime. Using the newly commissioned SOFIA airborne telescope and its 5-40 μm camera FORCAST, images of the entire BN/KL complex have been acquired. The 31.5 and 37.1 μm images represent the highest resolution observations (lsim4'') ever obtained of this region at these wavelengths. These observations reveal that the BN object is not the dominant brightness source in the complex at wavelengths >= 31.5 μm and that this distinction goes instead to the source IRc4. It was determined from these images and derived dust color temperature maps that IRc4 is also likely to be self-luminous. A new source of emission has also been identified at wavelengths >= 31.5 μm that coincides with the northeastern outflow lobe from the protostellar disk associated with radio source I. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100033284','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100033284">MAPIR: An Airborne Polarmetric Imaging Radiometer in Support of Hydrologic Satellite Observations</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Laymon, C.; Al-Hamdan, M.; Crosson, W.; Limaye, A.; McCracken, J.; Meyer, P.; Richeson, J.; Sims, W.; Srinivasan, K.; Varnevas, K. 2010-01-01 In this age of dwindling water resources and increasing demands, accurate estimation of water balance components at every scale is more critical to end users than ever before. Several near-term Earth science satellite missions are aimed at global hydrologic observations. The Marshall Airborne Polarimetric Imaging Radiometer (MAPIR) is a dual beam, dual angle polarimetric, scanning L band passive microwave radiometer system developed by the Observing Microwave Emissions for Geophysical Applications (OMEGA) team at MSFC to support algorithm development and validation efforts in support of these missions. MAPIR observes naturally-emitted radiation from the ground primarily for remote sensing of land surface brightness temperature from which we can retrieve soil moisture and possibly surface or water temperature and ocean salinity. MAPIR has achieved Technical Readiness Level 6 with flight heritage on two very different aircraft, the NASA P-3B, and a Piper Navajo. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA31B..07S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA31B..07S">Vertical Coupling and Observable Effects of Evanescent Acoustic-Gravity Waves in the Mesosphere and Thermosphere</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Snively, J. B. 2017-12-01 Our understanding of acoustic-gravity wave (AGW) dynamics at short periods ( minutes to hour) and small scales ( 10s to 100s km) in the mesosphere, thermosphere, and ionosphere (MTI) has benefited considerably from horizontally- and vertically-resolved measurements of layered species. These include, for example, imagery of the mesopause ( 80-100 km) airglow layers and vertical profiles of the sodium layer via lidar [e.g., Taylor and Hapgood, PSS, 36(10), 1988; Miller et al., PNAS, 112(49), 2015; Cao et al., JGR, 121, 2016]. In the thermosphere-ionosphere, AGW perturbations are also revealed in electron density profiles [Livneh et al., JGR, 112, 2007] and maps of total electron content (TEC) from global positioning system (GPS) receivers [Nishioka et al., GRL, 40(21), 2013]. To the extent that AGW signatures in layered species can be quantified, and the ambient atmospheric state measured or estimated, numerical models enable investigations of dynamics at intermediate altitudes that cannot readily be measured (e.g., above and below the 80-100 km mesopause region). Here, new 2D and 3D versions of the Model for Acoustic-Gravity Wave Interactions and Coupling (MAGIC) [e.g., Snively and Pasko, JGR, 113(A6), 2008, and references therein] are introduced and applied to investigate spectra of short-period AGW that can pass through the mesopause region to reach and impact the thermosphere. Simulation case studies are constructed to investigate both their signatures through the hydroxyl airglow layer [e.g., Snively et al., JGR 115(A11), 2010] and their effects above. These waves, with large vertical wavelengths and fast horizontal phase speeds, also include those that may be subject to evanescence at mesopause or in the middle-thermosphere, with potential for ducting or dissipation between where static stability is higher. Despite complicating interpretations of momentum fluxes, evanescence plays an under-appreciated role in vertical coupling by AGW [Walterscheid and Hecht </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.1787S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.1787S">Star Observations by Asteroid Multiband Imaging Camera (AMICA) on Hayabusa (MUSES-C) Cruising Phase</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Saito, J.; Hashimoto, T.; Kubota, T.; Hayabusa AMICA Team Muses-C is the first Japanese asteroid mission and also a technology demonstration one to the S-type asteroid, 25143 Itokawa (1998SF36). It was launched at May 9, 2003, and renamed Hayabusa after the spacecraft was confirmed to be on the interplanetary orbit. This spacecraft has the event of the Earth-swingby for gravitational assist in the way to Itokawa on 2004 May. The arrival to Itokawa is scheduled on 2005 summer. During the visit to Itokawa, the remote-sensing observation with AMICA, NIRS (Near Infrared Spectrometer), XRS (X-ray Fluorescence Spectrometer), and LIDAR are performed, and the spacecraft descends and collects the surface samples at the touch down to the surface. The captured asteroid sample will be returned to the Earth in the middle of 2007. The telescopic optical navigation camera (ONC-T) with seven bandpass filters (and one wide-band filter) and polarizers is called AMICA (Asteroid Multiband Imaging CAmera) when ONC-T is used for scientific observations. The AMICA's seven bandpass filters are nearly equivalent to the seven filters of the ECAS (Eight Color Asteroid Survey) system. Obtained spectroscopic data will be compared with previously obtained ECAS observations. AMICA also has four polarizers, which are located on one edge of the CCD chip (covering 1.1 x 1.1 degrees each). Using the polarizers of AMICA, we can obtain polarimetric information of the target asteroid's surface. Since last November, we planned the test observations of some stars and planets by AMICA and could successfully obtain these images. Here, we briefly report these observations and its calibration by the ground-based observational data. In addition, we also present a current status of AMICA. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3230945','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3230945">Multitemporal Observations of Sugarcane by TerraSAR-X Images</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Baghdadi, Nicolas; Cresson, Rémi; Todoroff, Pierre; Moinet, Soizic 2010-01-01 The objective of this study is to investigate the potential of TerraSAR-X (X-band) in monitoring sugarcane growth on Reunion Island (located in the Indian Ocean). Multi-temporal TerraSAR data acquired at various incidence angles (17°, 31°, 37°, 47°, 58°) and polarizations (HH, HV, VV) were analyzed in order to study the behaviour of SAR (synthetic aperture radar) signal as a function of sugarcane height and NDVI (Normalized Difference Vegetation Index). The potential of TerraSAR for mapping the sugarcane harvest was also studied. Radar signal increased quickly with crop height until a threshold height, which depended on polarization and incidence angle. Beyond this threshold, the signal increased only slightly, remained constant, or even decreased. The threshold height is slightly higher with cross polarization and higher incidence angles (47° in comparison with 17° and 31°). Results also showed that the co-polarizations channels (HH and VV) were well correlated. High correlation between SAR signal and NDVI calculated from SPOT-4/5 images was observed. TerraSAR data showed that after strong rains the soil contribution to the backscattering of sugarcane fields can be important for canes with heights of terminal visible dewlap (htvd) less than 50 cm (total cane heights around 155 cm). This increase in radar signal after strong rains could involve an ambiguity between young and mature canes. Indeed, the radar signal on TerraSAR images acquired in wet soil conditions could be of the same order for fields recently harvested and mature sugarcane fields, making difficult the detection of cuts. Finally, TerraSAR data at high spatial resolution were shown to be useful for monitoring sugarcane harvest when the fields are of small size or when the cut is spread out in time. The comparison between incidence angles of 17°, 37° and 58° shows that 37° is more suitable to monitor the sugarcane harvest. The cut is easily detectable on TerraSAR images for data acquired </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002SPIE.4814..296M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002SPIE.4814..296M">Flight Test Results of the Earth Observing-1 Advanced Land Imager Advanced Land Imager</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mendenhall, Jeffrey A.; Lencioni, Donald E.; Hearn, David R.; Digenis, Constantine J. 2002-09-01 The Advanced Land Imager (ALI) is the primary instrument on the Earth Observing-1 spacecraft (EO-1) and was developed under NASA's New Millennium Program (NMP). The NMP mission objective is to flight-validate advanced technologies that will enable dramatic improvements in performance, cost, mass, and schedule for future, Landsat-like, Earth Science Enterprise instruments. ALI contains a number of innovative features designed to achieve this objective. These include the basic instrument architecture, which employs a push-broom data collection mode, a wide field-of-view optical design, compact multi-spectral detector arrays, non-cryogenic HgCdTe for the short wave infrared bands, silicon carbide optics, and a multi-level solar calibration technique. The sensor includes detector arrays that operate in ten bands, one panchromatic, six VNIR and three SWIR, spanning the range from 0.433 to 2.35 μm. Launched on November 21, 2000, ALI instrument performance was monitored during its first year on orbit using data collected during solar, lunar, stellar, and earth observations. This paper will provide an overview of EO-1 mission activities during this period. Additionally, the on-orbit spatial and radiometric performance of the instrument will be compared to pre-flight measurements and the temporal stability of ALI will be presented. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DPS....4521104G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DPS....4521104G">The Ultraviolet Spectrograph (UVS) on ESA’s JUICE Mission</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gladstone, Randy; Retherford, K.; Steffl, A.; Eterno, J.; Davis, M.; Versteeg, M.; Greathouse, T.; Araujo, M.; Walther, B.; Persson, K.; Persyn, S.; Dirks, G.; McGrath, M.; Feldman, P.; Bagenal, F.; Spencer, J.; Schindhelm, E.; Fletcher, L. 2013-10-01 The Jupiter Icy Moons Explorer (JUICE) was selected in May 2012 as the first L-class mission of ESA’s Cosmic Vision Program. JUICE will launch in 2022 on a 7.6-year journey to the Jovian system, including a Venus and multiple Earth gravity assists, before entering Jupiter orbit in January 2030. JUICE will study the entire Jovian system for 3.5 years, concentrating on Europa, Ganymede, and Callisto, with the last 10 months spent in Ganymede orbit. The Ultraviolet Spectrograph (UVS) on JUICE was jointly selected by NASA and ESA as part of its ~130 kg payload of 11 scientific instruments. UVS is the fifth in a series of successful ultraviolet imaging spectrographs (Rosetta-Alice, New Horizons Pluto-Alice, LRO-LAMP) and is largely based on the most recent of these, Juno-UVS. It observes photons in the 55-210 nm wavelength range, at moderate spectral and spatial resolution along a 7.5-degree slit. A main entrance “airglow port” (AP) is used for most observations (e.g., airglow, aurora, surface mapping, and stellar occultations), while a separate “solar port” (SP) allows for solar occultations. Another aperture door, with a small hole through the centre, is used as a “high-spatial-resolution port” (HP) for detailed observations of bright targets. Time-tagging (pixel list mode) and programmable spectral imaging (histogram mode) allow for observational flexibility and optimal data management. As on Juno-UVS, the effects of penetrating electron radiation on electronic parts and data quality are substantially mitigated through contiguous shielding, filtering of pulse height amplitudes, management of high voltage settings, and careful use of radiation-hard, flight-tested parts. The science goals of UVS are to: 1) explore the atmospheres, plasma interactions, and surfaces of the Galilean satellites; 2) determine the dynamics, chemistry, and vertical structure of Jupiter’s upper atmosphere from equator to pole; and 3) investigate the Jupiter-Io connection by </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMSA41B..02W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMSA41B..02W">Using Heliospheric Imaging for Storm Forecasting - SMEI CME Observations as a Tool for Operational Forecasting at AFWA</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Webb, D. F.; Johnston, J. C.; Fry, C. D.; Kuchar, T. A. 2008-12-01 Observations of coronal mass ejections (CMEs) from heliospheric imagers such as the Solar Mass Ejection Imager (SMEI) can lead to significant improvements in operational space weather forecasting. We are working with the Air Force Weather Agency (AFWA) to ingest SMEI all-sky imagery with appropriate tools to help forecasters improve their operational space weather forecasts. We describe two approaches: 1) Near- real time analysis of propagating CMEs from SMEI images alone combined with near-Sun observations of CME onsets and, 2) Using these calculations of speed as a mid-course correction to the HAFv2 solar wind model forecasts. HAFv2 became operational at AFWA in late 2006. The objective is to determine a set of practical procedures that the duty forecaster can use to update or correct a solar wind forecast using heliospheric imager data. SMEI observations can be used inclusively to make storm forecasts, as recently discussed in Webb et al. (Space Weather, in press, 2008). We have developed a point-and-click analysis tool for use with SMEI images and are working with AFWA to ensure that timely SMEI images are available for analyses. When a frontside solar eruption occurs, especially if within about 45 deg. of Sun center, a forecaster checks for an associated CME observed by a coronagraph within an appropriate time window. If found, especially if the CME is a halo type, the forecaster checks SMEI observations about a day later, depending on the apparent initial CME speed, for possibly associated CMEs. If one is found, then the leading edge is measured over several successive frames and an elongation-time plot constructed. A minimum of three data points, i.e., over 3-4 orbits or about 6 hours, are necessary for such a plot. Using the solar source location and onset time of the CME from, e.g., SOHO observations, and assuming radial propagation, a distance-time relation is calculated and extrapolated to the 1 AU distance. As shown by Webb et al., the storm onset time </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM51C2196P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM51C2196P">The Origin of Low Altitude ENA Emissions from Storms in 2000-2005 as Observed by IMAGE/MENA</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Perez, J. D.; Sheehan, M. M.; Jahn, J.; Mackler, D.; Pollock, C. J. 2013-12-01 Low Altitude Emissions (LAEs) are prevalent features of Energetic Neutral Atom (ENA) images of the inner magnetosphere. It is believed that they are created by precipitating ions that reach altitudes near 500 km and then charge exchange with oxygen atoms, subsequently escaping to be observed by satellite borne ENA imagers. In this study, LAEs from the MENA instrument onboard the IMAGE satellite are studied in order to learn about the origin of the precipitating ions. Using the Tsyganenko 05 magnetic field model, the bright pixels capturing the LAEs are mapped to the equator. The LAEs are believed to originate from ions near their mirroring point, i.e., with pitch angles near 90o. Therefore the angle between the line-of-sight and the magnetic field at the point of origin is used to further constrain possible magnetospheric regions that are the origin of the ENAs. By observing the time dependence of the strength and location of the LAEs during geomagnetic storms in the years 2000-2005, the dynamics of the emptying and filling of the loss cone by injected particles is observed. Thus, information regarding the coupling between the inner magnetosphere and the ionosphere is obtained. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=S81-40245&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphoto%2Bimage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=S81-40245&hterms=photo+image&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphoto%2Bimage">Photos of earth observations taken by JPL with the Shuttle Imaging Radar-A</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 1981-01-01 Photos of earth observations taken by the Jet Propulsion Laboratory (JPL) with the Shuttle Imaging Radar-A (SIR-A). The first image show northern Peloponnesia and part of southern Greece. The Corinthian Canal is visible as a bright line cutting across the narrow Corinth Isthmus (upper center). Black area to the right is the Aegian Sea; on the left, the Gulf of Corinth. Islands to the right, starting at the top, are Salamis, Aegene and Angistrion, and the Peninsula of Methana. Southwest of the canal on the gulf coast is the city of Corinth, appearing as bright, white spots (40244); This image shows the Hamersley mountain range in Western Australia. A circular pattern of eroded folds surround a prominent granite dome, remnants of a volcanic past, is seen in the center of the photograph. The Hardey River is seen running vertically to the right of the center circular dome, and the small town of Paraburdoo appears as a patch of tiny bright rectangles in the lower right corner (40245). </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080021640','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080021640">Atmospheric Correction Prototype Algorithm for High Spatial Resolution Multispectral Earth Observing Imaging Systems</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Pagnutti, Mary 2006-01-01 This viewgraph presentation reviews the creation of a prototype algorithm for atmospheric correction using high spatial resolution earth observing imaging systems. The objective of the work was to evaluate accuracy of a prototype algorithm that uses satellite-derived atmospheric products to generate scene reflectance maps for high spatial resolution (HSR) systems. This presentation focused on preliminary results of only the satellite-based atmospheric correction algorithm. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930047931&hterms=environment+attitudes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denvironment%2Battitudes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930047931&hterms=environment+attitudes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denvironment%2Battitudes">A study of the impact of the Space Shuttle environment on faint far-UV geophysical and astronomical phenomena</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Lampton, Michael; Sasseen, Timothy P.; Wu, Xiaoyi; Bowyer, Stuart 1993-01-01 FAUST is a far ultraviolet (1400-1800 A) photon-counting imaging telescope featuring a wide field of view (7.6 deg) and a high sensitivity to extended emission features. During its flight as part of the ATLAS-1 payload aboard the STS-45 mission in March 1992, 19 deep-space nighttime viewing opportunities were utilized by FAUST. Here we report the observed fluxes and their time and space variations, and identify the signatures of postsunset airglow phenomena and Orbiter Vernier attitude control thruster firing events. We find that the Space Shuttle nighttime environment at 296 km altitude is often sufficiently dark to permit geophysical and astronomical UV observations down to levels on the order of 1000 photons/sq cm sr A sec, or 0.01 Rayleighs/A. We also find evidence for occasional geophysical fluxes of some tens or hundreds of Rayleighs in the upward-looking direction. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010004238','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010004238">The 1999 Leonid Multi-Instrument Aircraft Campaign - An Early Review</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Jenniskens, Peter; Butow, Steven J.; Fonda, Mark; DeVincenzi, Donald L. (Technical Monitor) 2000-01-01 The Leonid meteor storm of 1999 was observed from two B707-type research aircraft by a team of 35 scientists of seven nationalities over the Mediterranean Sea on Nov. 18, 1999. The mission was sponsored by various science programs of NASA, and offered the best possible observing conditions, free of clouds and at a prime location for viewing the storm. The 1999 mission followed a similar effort in 1998, improving upon mission strategy and scope. As before, spectroscopic and imaging experiments targeted meteors and persistent trains, but also airglow, aurora, elves and sprites. The research aimed to address outstanding questions in Planetary Science, Astronomy, Astrobiology and upper atmospheric research, including Aeronornie. In addition, near real-time flux measurements contributed to a USAF sponsored program for space weather awareness. An overview of the first results is given, which are discussed in preparation for future missions. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ChPhC..40h6203G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ChPhC..40h6203G">Application of a multiscale maximum entropy image restoration algorithm to HXMT observations</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Guan, Ju; Song, Li-Ming; Huo, Zhuo-Xi 2016-08-01 This paper introduces a multiscale maximum entropy (MSME) algorithm for image restoration of the Hard X-ray Modulation Telescope (HXMT), which is a collimated scan X-ray satellite mainly devoted to a sensitive all-sky survey and pointed observations in the 1-250 keV range. The novelty of the MSME method is to use wavelet decomposition and multiresolution support to control noise amplification at different scales. Our work is focused on the application and modification of this method to restore diffuse sources detected by HXMT scanning observations. An improved method, the ensemble multiscale maximum entropy (EMSME) algorithm, is proposed to alleviate the problem of mode mixing exiting in MSME. Simulations have been performed on the detection of the diffuse source Cen A by HXMT in all-sky survey mode. The results show that the MSME method is adapted to the deconvolution task of HXMT for diffuse source detection and the improved method could suppress noise and improve the correlation and signal-to-noise ratio, thus proving itself a better algorithm for image restoration. Through one all-sky survey, HXMT could reach a capacity of detecting a diffuse source with maximum differential flux of 0.5 mCrab. Supported by Strategic Priority Research Program on Space Science, Chinese Academy of Sciences (XDA04010300) and National Natural Science Foundation of China (11403014) </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8446E..1XD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8446E..1XD">A demonstration test of the dual-beam polarimetry differential imaging system for the high-contrast observation</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Dou, Jiangpei; Ren, Deqing; Zhu, Yongtian; Wang, Xue; Zhang, Xi; Li, Rong 2012-09-01 We propose a dual-beam polarimetry differential imaging test system that can be used for the direct imaging of the exoplanets. The system is composed of a liquid crystal variable retarder (LCVR) in the pupil to switch between two orthogonal polarized states, and a Wollaston prism (WP) that will be inserted before the final focal focus of the system to create two polarized images for the differential subtraction. Such a system can work separately or be integrated in the coronagraph system to enhance the high-contrast imaging. To demonstrate the feasibility of the proposed system, here we show the initial test result both with and without integrating our developed coronagraph. A unique feature for this system is that each channel can subtract with itself by using the retarder to rotate the planet's polarization orientation, which has the best performance according to our lab test results. Finally, it is shown that the polarimetry differential imaging system is a promising technique and can be used for the direct imaging observation of reflected lights from the exoplanets. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7263E..0IP','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7263E..0IP">Spatial frequency characteristics at image decision-point locations for observers with different radiological backgrounds in lung nodule detection</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Pietrzyk, Mariusz W.; Manning, David J.; Dix, Alan; Donovan, Tim 2009-02-01 Aim: The goal of the study is to determine the spatial frequency characteristics at locations in the image of overt and covert observers' decisions and find out if there are any similarities in different observers' groups: the same radiological experience group or the same accuracy scored level. Background: The radiological task is described as a visual searching decision making procedure involving visual perception and cognitive processing. Humans perceive the world through a number of spatial frequency channels, each sensitive to visual information carried by different spatial frequency ranges and orientations. Recent studies have shown that particular physical properties of local and global image-based elements are correlated with the performance and the level of experience of human observers in breast cancer and lung nodule detections. Neurological findings in visual perception were an inspiration for wavelet applications in vision research because the methodology tries to mimic the brain processing algorithms. Methods: The wavelet approach to the set of postero-anterior chest radiographs analysis has been used to characterize perceptual preferences observers with different levels of experience in the radiological task. Psychophysical methodology has been applied to track eye movements over the image, where particular ROIs related to the observers' fixation clusters has been analysed in the spaces frame by Daubechies functions. Results: Significance differences have been found between the spatial frequency characteristics at the location of different decisions. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28267641','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28267641">Graphene-supporting films and low-voltage STEM in SEM toward imaging nanobio materials without staining: Observation of insulin amyloid fibrils.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Ogawa, Takashi; Gang, Geun Won; Thieu, Minh Thu; Kwon, Hyuksang; Ahn, Sang Jung; Ha, Tai Hwan; Cho, Boklae 2017-05-01 Utilization of graphene-supporting films and low-voltage scanning transmission electron microscopy (LV-STEM) in scanning electron microscopy (SEM) is shown to be an effective means of observing unstained nanobio materials. Insulin amyloid fibrils, which are implicated as a cause of type II diabetes, are formed in vitro and observed without staining at room temperature. An in-lens cold field-emission SEM, equipped with an additional homemade STEM detector, provides dark field (DF)-STEM images in the low energy range of 5-30keV, together with secondary electron (SE) images. Analysis based on Lenz's theory is used to interpret the experimental results. Graphene films, where the fibrils are deposited, reduce the background level of the STEM images compared with instances when conventional amorphous carbon films are used. Using 30keV, which is lower than that for conventional TEM (100-300keV), together with low detection angles (15-55mrad) enhances the signals from the fibrils. These factors improve image quality, which enables observation of thin fibrils with widths of 7-8nm. STEM imaging clearly reveals a twisted-ribbon structure of a fibril, and SE imaging shows an emphasized striped pattern of the fibril. The LV-STEM in SEM enables acquisition of two types of images of an identical fibril in a single instrument, which is useful for understanding the structure. This study expands the application of SEM to other systems of interest, which is beneficial to a large number of users. The method in this study can be applied to the observation of various nanobio materials and analysis of their native structures, thus contributing to research in materials and life sciences. Copyright © 2017 Elsevier Ltd. All rights reserved. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active">24</li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active">25</li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMIN41A1682G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMIN41A1682G">Registering parameters and granules of wave observations: IMAGE RPI success story</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Galkin, I. A.; Charisi, A.; Fung, S. F.; Benson, R. F.; Reinisch, B. W. 2015-12-01 Modern metadata systems strive to help scientists locate data relevant to their research and then retrieve them quickly. Success of this mission depends on the organization and completeness of metadata. Each relevant data resource has to be registered; each content has to be described; each data file has to be accessible. Ultimately, data discoverability is about the practical ability to describe data content and location. Correspondingly, data registration has a "Parameter" level, at which content is specified by listing available observed properties (parameters), and a "Granule" level, at which download links are given to data records (granules). Until recently, both parameter- and granule-level data registrations were accomplished at NASA Virtual System Observatory easily by listing provided parameters and building Granule documents with URLs to the datafile locations, usually those at NASA CDAWeb data warehouse. With the introduction of the Virtual Wave Observatory (VWO), however, the parameter/granule concept faced a scalability challenge. The wave phenomenon content is rich with descriptors of the wave generation, propagation, interaction with propagation media, and observation processes. Additionally, the wave phenomenon content varies from record to record, reflecting changes in the constituent processes, making it necessary to generate granule documents at sub-minute resolution. We will present the first success story of registering 234,178 records of IMAGE Radio Plasma Imager (RPI) plasmagram data and Level 2 derived data products in ESPAS (near-Earth Space Data Infrastructure for e-Science), using the VWO-inspired wave ontology. The granules are arranged in overlapping display and numerical data collections. Display data include (a) auto-prospected plasmagrams of potential interest, (b) interesting plasmagrams annotated by human analysts or software, and (c) spectacular plasmagrams annotated by analysts as publication-quality examples of the RPI science </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930028542&hterms=SCI&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DSCI','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930028542&hterms=SCI&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DSCI">Ultraviolet Imaging Telescope observations of the ScI galaxy NGC 628 (M74)</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Chen, Peter C.; Cornett, Robert H.; Roberts, Morton S.; Bohlin, Ralph C.; Neff, Susan G.; O'Connell, Robert W.; Parise, Ronald A.; Smith, Andrew M.; Stecher, Theodore P. 1992-01-01 Ultraviolet images of NGC 628 at 1520 and 2490 A show that the nucleus has an oblong appearance and that the arms and disk exhibit features not seen in blue or H-alpha images. Aperture photometry of the nucleus gives results that are compatible with observations in other bandpasses and with models. The spiral arms appear more symmetrical in the UV than in other colors; in particular, two gaps are seen on either side of the nucleus. Combined UV and radio data appear to support a large-scale collective phenomenon, perhaps a quasi-static spiral structure mechanism, as being the dominant mode of spiral formation in this galaxy. We report the detection of a low surface brightness object at a distance of 7.6 arcmin southwest of the nucleus. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AJ....153...71F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AJ....153...71F">The Kepler Follow-up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution Imaging</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Furlan, E.; Ciardi, D. R.; Everett, M. E.; Saylors, M.; Teske, J. K.; Horch, E. P.; Howell, S. B.; van Belle, G. T.; Hirsch, L. A.; Gautier, T. N., III; Adams, E. R.; Barrado, D.; Cartier, K. M. S.; Dressing, C. D.; Dupree, A. K.; Gilliland, R. L.; Lillo-Box, J.; Lucas, P. W.; Wang, J. 2017-02-01 We present results from high-resolution, optical to near-IR imaging of host stars of Kepler Objects of Interest (KOIs), identified in the original Kepler field. Part of the data were obtained under the Kepler imaging follow-up observation program over six years (2009-2015). Almost 90% of stars that are hosts to planet candidates or confirmed planets were observed. We combine measurements of companions to KOI host stars from different bands to create a comprehensive catalog of projected separations, position angles, and magnitude differences for all detected companion stars (some of which may not be bound). Our compilation includes 2297 companions around 1903 primary stars. From high-resolution imaging, we find that ˜10% (˜30%) of the observed stars have at least one companion detected within 1″ (4″). The true fraction of systems with close (≲4″) companions is larger than the observed one due to the limited sensitivities of the imaging data. We derive correction factors for planet radii caused by the dilution of the transit depth: assuming that planets orbit the primary stars or the brightest companion stars, the average correction factors are 1.06 and 3.09, respectively. The true effect of transit dilution lies in between these two cases and varies with each system. Applying these factors to planet radii decreases the number of KOI planets with radii smaller than 2 {R}\\oplus by ˜2%-23% and thus affects planet occurrence rates. This effect will also be important for the yield of small planets from future transit missions such as TESS. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4316545','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4316545">Mirror Observation of Finger Action Enhances Activity in Anterior Intraparietal Sulcus: A Functional Magnetic Resonance Imaging Study</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Murayama, Takashi; Takasugi, Jun; Monma, Masahiko; Oga, Masaru 2013-01-01 Mirror therapy can be used to promote recovery from paralysis in patients with post-stroke hemiplegia, There are a lot of reports that mirror-image observation of the unilateral moving hand enhanced the excitability of the primary motor area (M1) ipsilateral to the moving hand in healthy subjects. but the neural mechanisms underlying its therapeutic effects are currently unclear. To investigate this issue, we used functional magnetic resonance imaging to measure activity in brain regions related to visual information processing during mirror image movement observation. Thirteen healthy subjects performed a finger-thumb opposition task with the left and right hands separately, with or without access to mirror observation. In the mirror condition, one hand was reflected in a mirror placed above the abdomen in the MRI scanner. In the masked mirror condition, subjects performed the same task but with the mirror obscured. In both conditions, the other hand was held at rest behind the mirror. A between-task comparison (mirror versus masked mirror) revealed significant activation in the ipsilateral hemisphere in the anterior intraparietal sulcus (aIP) while performing all tasks, regardless of which hand was used. The right aIP was significantly activated while moving the right hand. In contrast, in the left aIP, a small number of voxels showed a tendency toward activation during both left and right hand movement. The enhancement of ipsilateral aIP activity by the mirror image observation of finger action suggests that bimodal aIP neurons can be activated by visual information. We propose that activation in the M1 ipsilateral to the moving hand can be induced by information passing through the ventral premotor area from the aIP. PMID:25792898 </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRD..123..276H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRD..123..276H">Observations of the Breakdown of Mountain Waves Over the Andes Lidar Observatory at Cerro Pachon on 8/9 July 2012</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hecht, J. H.; Fritts, D. C.; Wang, L.; Gelinas, L. J.; Rudy, R. J.; Walterscheid, R. L.; Taylor, M. J.; Pautet, P. D.; Smith, S.; Franke, S. J. 2018-01-01 Although mountain waves (MWs) are thought to be a ubiquitous feature of the wintertime southern Andes stratosphere, it was not known whether these waves propagated up to the mesopause region until Smith et al. (2009) confirmed their presence via airglow observations. The new Andes Lidar Observatory at Cerro Pachon in Chile provided the opportunity for a further study of these waves. Since MWs have near-zero phase speed, and zero wind lines often occur in the winter upper mesosphere (80 to 100 km altitude) region due to the reversal of the zonal mean and tidal wind, MW breakdown may routinely occur at these altitudes. Here we report on very high spatial/temporal resolution observations of the initiation of MW breakdown in the mesopause region. Because the waves are nearly stationary, the breakdown process was observed over several hours; a much longer interval than has previously been observed for any gravity wave breakdown. During the breakdown process observations were made of initial horseshoe-shaped vortices, leading to successive vortex rings, as is also commonly seen in Direct Numerical Simulations (DNS) of idealized and multiscale gravity wave breaking. Kelvin-Helmholtz instability (KHI) structures were also observed to form. Comparing the structure of observed KHI with the results of existing DNS allowed an estimate of the turbulent kinematic viscosity. This viscosity was found to be around 25 m2/s, a value larger than the nominal viscosity that is used in models. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27279782','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27279782">Low-radio-frequency eclipses of the redback pulsar J2215+5135 observed in the image plane with LOFAR.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Broderick, J W; Fender, R P; Breton, R P; Stewart, A J; Rowlinson, A; Swinbank, J D; Hessels, J W T; Staley, T D; van der Horst, A J; Bell, M E; Carbone, D; Cendes, Y; Corbel, S; Eislöffel, J; Falcke, H; Grießmeier, J-M; Hassall, T E; Jonker, P; Kramer, M; Kuniyoshi, M; Law, C J; Markoff, S; Molenaar, G J; Pietka, M; Scheers, L H A; Serylak, M; Stappers, B W; Ter Veen, S; van Leeuwen, J; Wijers, R A M J; Wijnands, R; Wise, M W; Zarka, P 2016-07-01 The eclipses of certain types of binary millisecond pulsars (i.e. 'black widows' and 'redbacks') are often studied using high-time-resolution, 'beamformed' radio observations. However, they may also be detected in images generated from interferometric data. As part of a larger imaging project to characterize the variable and transient sky at radio frequencies <200 MHz, we have blindly detected the redback system PSR J2215+5135 as a variable source of interest with the Low-Frequency Array (LOFAR). Using observations with cadences of two weeks - six months, we find preliminary evidence that the eclipse duration is frequency dependent (∝ν -0.4 ), such that the pulsar is eclipsed for longer at lower frequencies, in broad agreement with beamformed studies of other similar sources. Furthermore, the detection of the eclipses in imaging data suggests an eclipsing medium that absorbs the pulsed emission, rather than scattering it. Our study is also a demonstration of the prospects of finding pulsars in wide-field imaging surveys with the current generation of low-frequency radio telescopes. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150003281','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150003281">Stroboscopic Image Modulation to Reduce the Visual Blur of an Object Being Viewed by an Observer Experiencing Vibration</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kaiser, Mary K. (Inventor); Adelstein, Bernard D. (Inventor); Anderson, Mark R. (Inventor); Beutter, Brent R. (Inventor); Ahumada, Albert J., Jr. (Inventor); McCann, Robert S. (Inventor) 2014-01-01 A method and apparatus for reducing the visual blur of an object being viewed by an observer experiencing vibration. In various embodiments of the present invention, the visual blur is reduced through stroboscopic image modulation (SIM). A SIM device is operated in an alternating "on/off" temporal pattern according to a SIM drive signal (SDS) derived from the vibration being experienced by the observer. A SIM device (controlled by a SIM control system) operates according to the SDS serves to reduce visual blur by "freezing" (or reducing an image's motion to a slow drift) the visual image of the viewed object. In various embodiments, the SIM device is selected from the group consisting of illuminator(s), shutter(s), display control system(s), and combinations of the foregoing (including the use of multiple illuminators, shutters, and display control systems). </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JASS...18...21W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JASS...18...21W">Studies of Gravity Waves Using Michelson Interferometer Measurements of OH (3-1) Bands</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Won, Young-In; Cho, Young-Min; Lee, Bang Yong; Kim, J. 2001-06-01 As part of a long-term program for polar upper atmospheric studies, temperatures and intensities of the OH (3-1) bands were derived from spectrometric observations of airglow emissions over King Sejong station (62.22o S, 301.25o E). These measurements were made with a Michelson interferometer to cover wavelength regions between 1000 nm and 2000 nm. A spectral analysis was performed to individual nights of data to acquire information on the waves in the upper mesosphere/lower thermosphere. It is assumed that the measured fluctuations in the intensity and temperature of the OH (3-1) airglow were caused by gravity waves propagating through the emission layer. Correlation of intensity and temperature variation revealed oscillations with periods ranging from 2 to 9 hours. We also calculated Krassovsky's parameter and compared with published values. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AAS...23144203J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AAS...23144203J">Wide-Field Imaging Telescope-0 (WIT0) with automatic observing system</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ji, Tae-Geun; Byeon, Seoyeon; Lee, Hye-In; Park, Woojin; Lee, Sang-Yun; Hwang, Sungyong; Choi, Changsu; Gibson, Coyne Andrew; Kuehne, John W.; Prochaska, Travis; Marshall, Jennifer L.; Im, Myungshin; Pak, Soojong 2018-01-01 We introduce Wide-Field Imaging Telescope-0 (WIT0), with an automatic observing system. It is developed for monitoring the variabilities of many sources at a time, e.g. young stellar objects and active galactic nuclei. It can also find the locations of transient sources such as a supernova or gamma-ray bursts. In 2017 February, we installed the wide-field 10-inch telescope (Takahashi CCA-250) as a piggyback system on the 30-inch telescope at the McDonald Observatory in Texas, US. The 10-inch telescope has a 2.35 × 2.35 deg field-of-view with a 4k × 4k CCD Camera (FLI ML16803). To improve the observational efficiency of the system, we developed a new automatic observing software, KAOS30 (KHU Automatic Observing Software for McDonald 30-inch telescope), which was developed by Visual C++ on the basis of a windows operating system. The software consists of four control packages: the Telescope Control Package (TCP), the Data Acquisition Package (DAP), the Auto Focus Package (AFP), and the Script Mode Package (SMP). Since it also supports the instruments that are using the ASCOM driver, the additional hardware installations become quite simplified. We commissioned KAOS30 in 2017 August and are in the process of testing. Based on the WIT0 experiences, we will extend KAOS30 to control multiple telescopes in future projects. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950035282&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtwilight','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950035282&hterms=twilight&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtwilight">Recent observations of the OI 8446 A emission over Millstone Hill</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Lancaster, R. S.; Kerr, R. B.; Ng, K.; Noto, J.; Franco, M.; Solomon, Stanley C. 1994-01-01 Evening twilight spectra of the OI 8446 A emission were obtained during May and June of 1993 using a single-etalon, pressure scanning, Fabry-Perot interferometer located in the Millstone Hill Optical Facility. The goals of this work are to positively identify the 8446 A emission in the twilight airglow and to determine the intensity decay as a function of solar depression angle. Also, a study of the relative triplet line strengths is performed in hopes of establishing the importance of the primary excitation mechanisms (photoelectron impact or Bowen fluorescence) during the twilight period. Although absent in most of the data, a distinct auroral influence is also found to contribute considerably, on occasion, to the emission over Millstone Hill. The ratio of the combined 8446.26 A and 8446.38 A intensities to the 8446.76 A intensity varies as 0.13 +/- 0.03 per degree of solar depression angle, indicating that secondary excitation mechanisms are becoming increasingly important as evening twilight progresses. Bowen fluorescence is not found to be the primary excitation mechanism at any time during twilight, contributing just a few Rayleighs at most. These observations are an important first step toward a better characterization of highly variable thermospheric oxygen concentrations through ground-based measurements of the OI 8446 A emission. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10136E..0NP','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10136E..0NP">Real space channelization for generic DBT system image quality evaluation with channelized Hotelling observer</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Petrov, Dimitar; Cockmartin, Lesley; Marshall, Nicholas; Vancoillie, Liesbeth; Young, Kenneth; Bosmans, Hilde 2017-03-01 Digital breast tomosynthesis (DBT) is a relatively new 3D mammography technique that promises better detection of low contrast masses than conventional 2D mammography. The parameter space for DBT is large however and finding an optimal balance between dose and image quality remains challenging. Given the large number of conditions and images required in optimization studies, the use of human observers (HO) is time consuming and certainly not feasible for the tuning of all degrees of freedom. Our goal was to develop a model observer (MO) that could predict human detectability for clinically relevant details embedded within a newly developed structured phantom for DBT applications. DBT series were acquired on GE SenoClaire 3D, Giotto Class, Fujifilm AMULET Innovality and Philips MicroDose systems at different dose levels, Siemens Inspiration DBT acquisitions were reconstructed with different algorithms, while a larger set of DBT series was acquired on Hologic Dimensions system for first reproducibility testing. A channelized Hotelling observer (CHO) with Gabor channels was developed The parameters of the Gabor channels were tuned on all systems at standard scanning conditions and the candidate that produced the best fit for all systems was chosen. After tuning, the MO was applied to all systems and conditions. Linear regression lines between MO and HO scores were calculated, giving correlation coefficients between 0.87 and 0.99 for all tested conditions. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990019629&hterms=doolittle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D10%26Ntt%3Ddoolittle','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990019629&hterms=doolittle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D10%26Ntt%3Ddoolittle">Conjugate Observations of Optical Aurora with POLAR Satellite and Ground Based Imagers in Antarctica</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Mende, S. H.; Frey, H.; Vo, H.; Geller, S. P.; Doolittle, J. H.; Spann, J. F., Jr. 1998-01-01 Operation of the ultraviolet imager on the POLAR satellite permits the observation of Aurora Borealis in daylight during northern summer. With optical imagers in the Automatic Geophysical Observatories (AGO-s) large regions of the oval of Aurora Australis can be observed simultaneously during the southern winter polar night. This opportunity permits conducting a systematic study of the properties of auroras on opposite ends of the same field line. It is expected that simultaneously observed conjugate auroras occurring on closed field lines should be similar to each other in appearance because of the close connection between the two hemispheres through particle scattering and mirroring processes. On open or greatly distorted field lines there is no a priori expectation of similarity between conjugate auroras. To investigate the influence of different IMF conditions on auroral behavior we have examined conjugate data for periods of southward IMF. Sudden brightening and subsequent poleward expansions are observed to occur simultaneously in both hemispheres. The POLAR data show that sudden brightening are initiated at various local time regions. When the local time of this region is in the field of view of the AGO station network then corresponding brightening is also found to occur in the southern hemisphere. Large features such as substorm induced westward propagation and resulting auroral brightening seem to occur simultaneously on conjugate hemispheres. The widely different view scales make it difficult to make unique identification of individual auroral forms in the POLAR and in the ground based data but in a general sense the data is consistent with conjugate behavior. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030054367&hterms=coulomb+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcoulomb%2Blaw','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030054367&hterms=coulomb+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcoulomb%2Blaw">Theoretical Model Images and Spectra for Comparison with HESSI and Microwave Observations of Solar Flares</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Fisher, Richard R. (Technical Monitor); Holman, G. D.; Sui, L.; McTiernan, J. M.; Petrosian, V. 2003-01-01 We have computed bremsstrahlung and gyrosynchrotron images and spectra from a model flare loop. Electrons with a power-law energy distribution are continuously injected at the top of a semi-circular magnetic loop. The Fokker-Planck equation is integrated to obtain the steady-state electron distribution throughout the loop. Coulomb scattering and energy losses and magnetic mirroring are included in the model. The resulting electron distributions are used to compute the radiative emissions. Sample images and spectra are presented. We are developing these models for the interpretation of the High Energy Solar Spectroscopic Imager (HESSI) x-ray/gamma ray data and coordinated microwave observations. The Fokker-Planck and radiation codes are available on the Web at http://hesperia.gsfc.nasa.gov/hessi/modelware.htm This work is supported in part by the NASA Sun-Earth Connection Program. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4352060','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4352060">Expanding Imaging Capabilities for Microfluidics: Applicability of Darkfield Internal Reflection Illumination (DIRI) to Observations in Microfluidics</a> <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Kawano, Yoshihiro; Otsuka, Chino; Sanzo, James; Higgins, Christopher; Nirei, Tatsuo; Schilling, Tobias; Ishikawa, Takuji 2015-01-01 Microfluidics is used increasingly for engineering and biomedical applications due to recent advances in microfabrication technologies. Visualization of bubbles, tracer particles, and cells in a microfluidic device is important for designing a device and analyzing results. However, with conventional methods, it is difficult to observe the channel geometry and such particles simultaneously. To overcome this limitation, we developed a Darkfield Internal Reflection Illumination (DIRI) system that improved the drawbacks of a conventional darkfield illuminator. This study was performed to investigate its utility in the field of microfluidics. The results showed that the developed system could clearly visualize both microbubbles and the channel wall by utilizing brightfield and DIRI illumination simultaneously. The methodology is useful not only for static phenomena, such as clogging, but also for dynamic phenomena, such as the detection of bubbles flowing in a channel. The system was also applied to simultaneous fluorescence and DIRI imaging. Fluorescent tracer beads and channel walls were observed clearly, which may be an advantage for future microparticle image velocimetry (μPIV) analysis, especially near a wall. Two types of cell stained with different colors, and the channel wall, can be recognized using the combined confocal and DIRI system. Whole-slide imaging was also conducted successfully using this system. The tiling function significantly expands the observing area of microfluidics. The developed system will be useful for a wide variety of engineering and biomedical applications for the growing field of microfluidics. PMID:25748425 </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25748425','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25748425">Expanding imaging capabilities for microfluidics: applicability of darkfield internal reflection illumination (DIRI) to observations in microfluidics.</a> <a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Kawano, Yoshihiro; Otsuka, Chino; Sanzo, James; Higgins, Christopher; Nirei, Tatsuo; Schilling, Tobias; Ishikawa, Takuji 2015-01-01 Microfluidics is used increasingly for engineering and biomedical applications due to recent advances in microfabrication technologies. Visualization of bubbles, tracer particles, and cells in a microfluidic device is important for designing a device and analyzing results. However, with conventional methods, it is difficult to observe the channel geometry and such particles simultaneously. To overcome this limitation, we developed a Darkfield Internal Reflection Illumination (DIRI) system that improved the drawbacks of a conventional darkfield illuminator. This study was performed to investigate its utility in the field of microfluidics. The results showed that the developed system could clearly visualize both microbubbles and the channel wall by utilizing brightfield and DIRI illumination simultaneously. The methodology is useful not only for static phenomena, such as clogging, but also for dynamic phenomena, such as the detection of bubbles flowing in a channel. The system was also applied to simultaneous fluorescence and DIRI imaging. Fluorescent tracer beads and channel walls were observed clearly, which may be an advantage for future microparticle image velocimetry (μPIV) analysis, especially near a wall. Two types of cell stained with different colors, and the channel wall, can be recognized using the combined confocal and DIRI system. Whole-slide imaging was also conducted successfully using this system. The tiling function significantly expands the observing area of microfluidics. The developed system will be useful for a wide variety of engineering and biomedical applications for the growing field of microfluidics. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22649059-su-clinically-observed-discrepancy-between-image-based-log-based-mlc-position','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22649059-su-clinically-observed-discrepancy-between-image-based-log-based-mlc-position">SU-F-T-469: A Clinically Observed Discrepancy Between Image-Based and Log- Based MLC Position</a> <a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Neal, B; Ahmed, M; Siebers, J 2016-06-15 Purpose: To present a clinical case which challenges the base assumption of log-file based QA, by showing that the actual position of a MLC leaf can suddenly deviate from its programmed and logged position by >1 mm as observed with real-time imaging. Methods: An EPID-based exit-fluence dosimetry system designed to prevent gross delivery errors was used in cine mode to capture portal images during treatment. Visual monitoring identified an anomalous MLC leaf pair gap not otherwise detected by the automatic position verification. The position of the erred leaf was measured on EPID images and log files were analyzed for themore » treatment in question, the prior day’s treatment, and for daily MLC test patterns acquired on those treatment days. Additional standard test patterns were used to quantify the leaf position. Results: Whereas the log file reported no difference between planned and recorded positions, image-based measurements showed the leaf to be 1.3±0.1 mm medial from the planned position. This offset was confirmed with the test pattern irradiations. Conclusion: It has been clinically observed that log-file derived leaf positions can differ from their actual positions by >1 mm, and therefore cannot be considered to be the actual leaf positions. This cautions the use of log-based methods for MLC or patient quality assurance without independent confirmation of log integrity. Frequent verification of MLC positions through independent means is a necessary precondition to trusting log file records. Intra-treatment EPID imaging provides a method to capture departures from MLC planned positions. Work was supported in part by Varian Medical Systems.« less </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950048242&hterms=Petit&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPetit','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950048242&hterms=Petit&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPetit">Ultraviolet imaging telescope and optical emission-line observations of H II regions in M81</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Hill, Jesse K.; Cheng, K.-P.; Bohlin, Ralph C.; Cornett, Robert H.; Hintzen, P. M. N.; O'Connell, Robert W.; Roberts, Morton S.; Smith, Andrew M.; Smith, Eric P.; Stecher, Theodore P. 1995-01-01 Images of the type Sab spiral galaxy M81 were obtained in far-UV and near-UV bands by the Ultraviolet Imaging Telescope (UIT) during the Astro-1 Spacelab mission of 1990 December. Magnitudes in the two UV bands are determined for 52 H II regions from the catalog of Petit, Sivan, & Karachentsev (1988). Fluxes of the H-alpha and H-beta emission lines are determined from CCD images. Extinctions for the brightest H II regions are determined from observed Balmer decrements. Fainter H II regions are assigned the average of published radio-H-alpha extinctions for several bright H II regions. The radiative transfer models of Witt, Thronson, & Capuano (1992) are shown to predict a relationship between Balmer Decrement and H-alpha extinction consistent with observed line and radio fluxes for the brightest 7 H II regions and are used to estimate the UV extinction. Ratios of Lyman continuum with ratios predicted by model spectra computed for initial mass function (IMF) slope equal to -1.0 and stellar masses ranging from 5 to 120 solar mass. Ages and masses are estimated by comparing the H-alpha and far-UV fluxes and their ratio with the models. The total of the estimated stellar masses for the 52 H II regions is 1.4 x 10(exp 5) solar mass. The star-formation rate inferred for M81 from the observed UV and H-alpha fluxes is low for a spiral galaxy at approximately 0.13 solar mass/yr, but consistent with the low star-formation rates obtained by Kennicutt (1983) and Caldwell et al. (1991) for early-type spirals. </li> <li> <a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010100545&hterms=fourier&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dfourier','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010100545&hterms=fourier&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dfourier">Demonstration of Imaging Fourier Transform Spectrometer (FTS) Performance for Planetary and Geostationary Earth Observing</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Revercomb, Henry E.; Sromovsky, Lawrence A.; Fry, Patrick M.; Best, Fred A.; LaPorte, Daniel D. 2001-01-01 The combination of massively parallel spatial sampling and accurate spectral radiometry offered by imaging FTS makes it extremely attractive for earth and planetary remote sensing. We constructed a breadboard instrument to help assess the potential for planetary applications of small imaging FTS instruments in the 1 - 5 micrometer range. The results also support definition of the NASA Geostationary Imaging FTS (GIFTS) instrument that will make key meteorological and climate observations from geostationary earth orbit. The Planetary Imaging FTS (PIFTS) breadboard is based on a custom miniaturized Bomen interferometer that uses corner cube reflectors, a wishbone pivoting voice-coil delay scan mechanism, and a laser diode metrology system. The interferometer optical output is measured by a commercial infrared camera procured from Santa Barbara Focalplane. It uses an InSb 128x128 detector array that covers the entire FOV of the instrument when coupled with a 25 mm focal length commercial camera lens. With appropriate lenses and cold filters the instrument can be used from the visible to 5 micrometers. The delay scan is continuous, but slow, covering the maximum range of +/- 0.4 cm in 37.56 sec at a rate of 500 image frames per second. Image exposures are timed to be centered around predicted zero crossings. The design allows for prediction algorithms that account for the most recent fringe rate so that timing jitter produced by scan speed variations can be minimized. Response to a fixed source is linear with exposure time nearly to the point of saturation. Linearity with respect to input variations was demonstrated to within 0.16% using a 3-point blackbody calibration. Imaging of external complex scenes was carried out at low and high spectral resolution. These require full complex calibration to remove background contributions that vary dramatically over the instrument FOV. Testing is continuing to demonstrate the precise radiometric accuracy and noise characteristics. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4741915S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4741915S">New Observations of Molecular Nitrogen by the Imaging Ultraviolet Spectrograph on MAVEN</a> <a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Stevens, Michael H.; Evans, J. S.; Schneider, Nicholas M.; Stewart, A. I. F.; Deighan, Justin; Jain, Sonal K.; Crismani, Matteo M. J.; Stiepen, Arnaud; Chaffin, Michael S.; McClintock, William E.; Holsclaw, Greg M.; Lefevre, Franck; Montmessin, Franck; Lo, Daniel Y.; Clarke, John T.; Bougher, Stephen W.; Jakosky, Bruce M. 2015-11-01 The Martian ultraviolet dayglow provides information on the basic state of the Martian upper atmosphere. The Imaging Ultraviolet Spectrograph (IUVS) on NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission has observed Mars at mid and far-UV wavelengths since its arrival in September 2014. In this work, we describe a linear regression method used to extract components of UV spectra from IUVS limb observations and focus in particular on molecular nitrogen (N2) photoelectron excited emissions. We identify N2 Lyman-Birge-Hopfield (LBH) emissions for the first time at Mars and we also confirm the tentative identification of N2 Vegard-Kaplan (VK) emissions. We compare observed VK and LBH limb radiance profiles to model results between 90 and 210 km. Finally, we compare retrieved N2 density profiles to general circulation (GCM) model results. Contrary to earlier analyses using other satellite data that indicated N2 densities were a factor of three less than predictions, we find that N2 abundances exceed GCM results by about a factor of two at 130 km but are in agreement at 150 km. </li> <li> <a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002681','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002681">Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites</a> <a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Fung, Shing F.; Hashimoto, KoZo; Kojima, Hirotsugu; Boardson, Scott A.; Garcia, Leonard N.; Matsumoto, Hiroshi; Green, James L.; Reinisch, Bodo W. 2013-01-01 We report the simultaneous detection of a terrestrial myriametric radio burst (TMRB) by IMAGE and Geotail on 19 August 2001. The TMRB was confined in time (0830-1006 UT) and frequency (12-50kHz). Comparisons with all known nonthermal myriametric radiation components reveal that the TMRB might be a distinct radiation with a source that is unrelated to the previously known radiation. Considerations of beaming from spin-modulation analysis and observing satellite and source locations suggest that the TMRB may have a fan beamlike radiation pattern emitted by a discrete, dayside source located along the poleward edge of magnetospheric cusp field lines. TMRB responsiveness to IMF Bz and By orientations suggests that a possible source of the TMRB could be due to dayside magnetic reconnection instigated by northward interplanetary field condition. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active">25</li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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Sample records for airglow imaging observations