Science.gov

Sample records for actual satellite observations

  1. Satellite observations of ethylene

    NASA Astrophysics Data System (ADS)

    Dolan, W.; Payne, V.; Kulawik, S. S.; Bowman, K. W.

    2015-12-01

    Ethylene (C2H4) is a trace gas commonly associated with boreal fire plumes and the petrochemical industry. It has a short lifetime (~1-2 days) in the troposphere due to its reaction with OH. Chemical destruction of ethylene in the atmosphere leads to the production of ozone precursors such as carbon monoxide (CO) and formaldehyde. The Tropospheric Emission Spectrometer (TES) is a Fourier Transform Spectrometer aboard the Aura satellite that measures thermal infrared radiances with high spectral resolution. Trace gas products retrieved routinely from TES spectra include O3, CO, H2O, HDO, CH4, NH3, HCOOH, CH3OH, with OCS and PAN to be included in the next data release. The TES spectra also includes a wealth of untapped information about other trace gasses including ethylene. Ethylene was first observed in TES spectra by Alvarado et al. (2011), though it has yet to be developed into an operational product. Our study focuses on the detection and initial quantitative estimates of ethylene in TES special observations taken in support of the 2008 ARCTAS mission. Initial observations of HCN in the spectra may provide a way to distinguish between fire plume and petrochemical derived ethylene. Results indicate a correlation between ethylene and CO in fresh fire plumes but not in older plumes, consistent with the gas's short lifetime. The approach adopted here to detect ethylene in the TES 2008 ARCTAS special observations can easily be expanded to larger datasets, including those from other thermal infrared sounders as well as to other trace gases.

  2. Satellite observations of contrails

    NASA Astrophysics Data System (ADS)

    Mannstein, H.; Meyer, R.; Wendlimg, P.

    2003-04-01

    A direct human influence on cirrus coverage close to the tropopause is given by the contrails produced from air-traffic, which is currently increasing at approximately 7%/year. The infrared channels of the Advanced Very High Resolution Radiometer (AVHRR) onboard of the weather satellites of the NOAA series are used for the automated detection of linear contrails. Results from studies on contrail coverage and the resulting radiative impact over Europe, SE and E-Asia will be presented and compared to results from model calculations.

  3. Stereoscopic observations from meteorological satellites

    NASA Astrophysics Data System (ADS)

    Hasler, A. F.; Mack, R.; Negri, A.

    The capability of making stereoscopic observations of clouds from meteorological satellites is a new basic analysis tool with a broad spectrum of applications. Stereoscopic observations from satellites were first made using the early vidicon tube weather satellites (e.g., Ondrejka and Conover [1]). However, the only high quality meteorological stereoscopy from low orbit has been done from Apollo and Skylab, (e.g., Shenk et al. [2] and Black [3], [4]). Stereoscopy from geosynchronous satellites was proposed by Shenk [5] and Bristor and Pichel [6] in 1974 which allowed Minzner et al. [7] to demonstrate the first quantitative cloud height analysis. In 1978 Bryson [8] and desJardins [9] independently developed digital processing techniques to remap stereo images which made possible precision height measurement and spectacular display of stereograms (Hasler et al. [10], and Hasler [11]). In 1980 the Japanese Geosynchronous Satellite (GMS) and the U.S. GOES-West satellite were synchronized to obtain stereo over the central Pacific as described by Fujita and Dodge [12] and in this paper. Recently the authors have remapped images from a Low Earth Orbiter (LEO) to the coordinate system of a Geosynchronous Earth Orbiter (GEO) and obtained stereoscopic cloud height measurements which promise to have quality comparable to previous all GEO stereo. It has also been determined that the north-south imaging scan rate of some GEOs can be slowed or reversed. Therefore the feasibility of obtaining stereoscopic observations world wide from combinations of operational GEO and LEO satellites has been demonstrated. Stereoscopy from satellites has many advantages over infrared techniques for the observation of cloud structure because it depends only on basic geometric relationships. Digital remapping of GEO and LEO satellite images is imperative for precision stereo height measurement and high quality displays because of the curvature of the earth and the large angular separation of the

  4. Seasonal streamflow estimation employing satellite snowcover observations

    NASA Technical Reports Server (NTRS)

    Rango, A.; Salomonson, V. V.; Foster, J. L.

    1975-01-01

    Low resolution meteorological satellite and high resolution earth resources satellite data have been used to map snow covered area over the upper Indus River and the Wind River Mountains of Wyoming, respectively. For the Indus River early spring snow covered area was extracted and related to April through June stream flow from 1967-1971 using a regression equation. Prediction of the April-June 1972 stream flow from the satellite data was within three percent of the actual total. Composited results from two years of data over seven Wind River Mountain watersheds indicated that LANDSAT-1 snow cover observations, separated on the basis of watershed elevation, could also be related to runoff in significant regression equations.

  5. Korea Earth Observation Satellite Program

    NASA Astrophysics Data System (ADS)

    Baek, Myung-Jin; Kim, Zeen-Chul

    via Korea Aerospace Research Institute (KARI) as the prime contractor in the area of Korea earth observation satellite program to enhance Korea's space program development capability. In this paper, Korea's on-going and future earth observation satellite programs are introduced: KOMPSAT- 1 (Korea Multi Purpose Satellite-1), KOMPSAT-2 and Communication, Broadcasting and Meteorological Satellite (CBMS) program. KOMPSAT-1 satellite successfully launched in December 1999 with Taurus launch vehicle. Since launch, KOMPSAT-1 is downlinking images of Korea Peninsular every day. Until now, KOMPSAT-1 has been operated more than 2 and half years without any major hardware malfunction for the mission operation. KOMPSAT-1 payload has 6.6m panchromatic spatial resolution at 685 km on-orbit and the spacecraft bus had NASA TOMS-EP (Total Ozone Mapping Spectrometer-Earth Probe) spacecraft bus heritage designed and built by TRW, U.S.A.KOMPSAT-1 program was international co-development program between KARI and TRW funded by Korean Government. be launched in 2004. Main mission objective is to provide geo-information products based on the multi-spectral high resolution sensor called Multi-Spectral Camera (MSC) which will provide 1m panchromatic and 4m multi-spectral high resolution images. ELOP of Israel is the prime contractor of the MSC payload system and KARI is the total system prime contractor including spacecraft bus development and ground segment. KARI also has the contract with Astrium of Europe for the purpose of technical consultation and hardware procurement. Based on the experience throughout KOMPSAT-1 and KOMPSAT-2 space system development, Korea is expecting to establish the infrastructure of developing satellite system. Currently, KOMPSAT-2 program is in the critical design stage. are scheduled to launch in 2008 and in 2014, respectively. The mission of CBMS consists of two areas. One is of space technology test for the communications mission, and the other is of a real

  6. Satellite Observations of Tropospheric Chemistry

    NASA Technical Reports Server (NTRS)

    Singh, Hanwant B.; Jacob, Daniel J.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    The troposphere is an essential component of the earth's life support system as well as the gateway for the exchange of chemicals between different geochemical reservoirs of the earth. The chemistry of the troposphere is sensitive to perturbation from a wide range of natural phenomena and human activities. The societal concern has been greatly enhanced in recent decades due to ever increasing pressures of population growth and industrialization. Chemical changes within the troposphere control a vast array of processes that impact human health, the biosphere, and climate. A main goal of tropospheric chemistry research is to measure and understand the response of atmospheric composition to natural and anthropogenic perturbations, and to develop the capability to predict future change. Atmospheric chemistry measurements are extremely challenging due to the low concentrations of critical species and the vast scales over which the observations must be made. Available tropospheric data are mainly from surface sites and aircraft missions. Because of the limited temporal extent of aircraft observations, we have very limited information on tropospheric composition above the surface. This situation can be contrasted to the stratosphere, where satellites have provided critical and detailed chemical data on the global distribution of key trace gases.

  7. Observing iodine monoxide from satellite

    NASA Astrophysics Data System (ADS)

    Schoenhardt, Anja; Richter, Andreas; Begoin, Mathias; Wittrock, Folkard; Burrows, John P.

    Iodine and iodine monoxide (IO) belong to the group of reactive halogen species, and they may impact on atmospheric chemical composition and the radiation budget. Vice versa, sur-rounding conditions may influence the emissions and pathways of iodine compounds. Although atmospheric amounts of iodine are typically fairly small, the impact may still be substantial. Iodine radicals are photolytically released from precursors and may then cause catalytic ozone depletion. In this reaction with ozone, IO is produced, a molecule which plays a central role in the iodine cycling. Via self reactions of IO, higher iodine oxides form and initiate the formation of new particles, which may change the atmospheric radiation balance. Apart from that, many living species, including human beings, vertebrates in general, but also micro-and macroalgae species, e.g., depend on the supply with iodine. Consequently, it is necessary to understand the cycling of iodine through the different components of the Earth system. Although increas-ing research effort in the form of field, laboratory and modeling studies has strongly improved our knowledge and understanding of iodine abundances and impact, still many open questions remain. The relevance of iodine on a global scale is not well known yet; sources are not well quantified and release processes are not fully understood. Since recently, IO may be observed from space by the SCIAMACHY instrument on the EN-VISAT satellite, which is in a near-polar, sun-synchronous orbit. Nadir observations from SCIAMACHY have been analysed for the IO absorption signature in the visible wavelength range for several mission years. IO amounts are typically close to the limit of detectability of SCIAMACHY. Detecting such small quantities, careful attention needs to be paid to system-atic errors, spectral correlations and resulting retrieval artefacts. Subsequently, appropriate temporal averaging is utilised to improve the signal-to-noise ratio. The resulting

  8. Satellite observation of effusive volcanism

    USGS Publications Warehouse

    Williams, R.S.; Friedman, J.D.

    1970-01-01

    Infrared emission from an active effusive volcanic eruption on Surtsey, Vestmannaeyjar, Iceland, was recorded by airborne and satellite infrared systems at irregular intervals between 19 August and 3 October 1966. Ground and lava temperature measurements and volumetric lava outflow data permitted a comparison to be made between total thermal-energy yield and radiant emission recorded by the satellite system. The Nimbus HRIR recorded radiant emission at a level of about 3% of the estimated total thermal yield.

  9. Landsat—Earth observation satellites

    USGS Publications Warehouse

    ,

    2015-11-25

    Since 1972, Landsat satellites have continuously acquired space-based images of the Earth’s land surface, providing data that serve as valuable resources for land use/land change research. The data are useful to a number of applications including forestry, agriculture, geology, regional planning, and education. Landsat is a joint effort of the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA). NASA develops remote sensing instruments and the spacecraft, then launches and validates the performance of the instruments and satellites. The USGS then assumes ownership and operation of the satellites, in addition to managing all ground reception, data archiving, product generation, and data distribution. The result of this program is an unprecedented continuing record of natural and human-induced changes on the global landscape.

  10. Severe storms observing satellite (STORMSAT)

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The primary payload for this satellite is the Advanced Atmospheric Sounding and Imaging Radiometer which will perform precise infrared temperature sounding and visible/infrared imaging from geostationary orbit. A secondary payload instrument which may be utilized on STORMSAT is the Microwave Atmospheric Sounding Radiometer which provides an independent set of temperature and humidity sounding in cloudy, meteorologically active regions. The study provides satellite designs and identifies mission-unique subsystems using the Multimission Modular Spacecraft using a Shuttle/Interim Upper Stage launch vehicle.

  11. Merging raster meteorological data with low resolution satellite images for improved estimation of actual evapotranspiration

    NASA Astrophysics Data System (ADS)

    Cherif, Ines; Alexandridis, Thomas; Chambel Leitao, Pedro; Jauch, Eduardo; Stavridou, Domna; Iordanidis, Charalampos; Silleos, Nikolaos; Misopolinos, Nikolaos; Neves, Ramiro; Safara Araujo, Antonio

    2013-04-01

    Actual evapotranspiration (ETa) can be estimated using Energy Balance models and remotely sensed data. In particular, satellite images acquired in visible, near and thermal infrared parts of the spectrum have been used with the Surface Energy Balance Algorithm for Land (SEBAL) to estimate actual evapotranspiration. This algorithm is solving the Energy Balance Equation using data from a meteorological station present in the vicinity, and assumes the meteorological conditions homogeneous over the study area. Most often, data from a representative weather station are used. This assumption may lead to substantial errors in areas with high spatial variability in weather parameters. In this paper, the ITA-MyWater algorithms (Integrated Thermodynamic Algorithms for MyWater project), an adaptation of SEBAL was merged together with spatially distributed meteorological data to increase the accuracy of ETa estimations at regional scale using MODIS satellite images. The major changes introduced to migrate from point to raster are that (i) air temperature and relative humidity maps are used for the estimation of the Energy Balance terms, including instantaneous net radiation and soil heat flux and (ii) the variability of wind speed is taken into account to generate maps of the aerodynamic resistance, sensible heat flux and difference between soil and air temperature at the boundary conditions (at dry and wet pixels). The approach was applied in the river basin of Tamega in Portugal, where actual evapotranspiration was estimated for several MODIS 8-day periods from spring to winter of the same year. The raster meteorological maps were produced by the MM5 weather forecast model. Daily reference evapotranspiration was calculated with MOHID LAND model. Using a temporal integration technique and the daily reference evapotranspiration maps, the cumulative evapotranspiration over the MODIS 8-day period was estimated and compared to the global evapotranspiration MODIS product (MOD16A2

  12. The dynamics of Martian satellites from observations

    NASA Astrophysics Data System (ADS)

    Emelyanov, N. V.; Vashkovyak, S. N.; Nasonova, L. P.

    1993-01-01

    This paper deals with the study of the motion of Martian satellites and with the determination of kinematic and dynamic parameters describing this system of satellites and planet. The values of these parameters are found on the basis of all available data of ground-based and space-based observations of Phobos and Deimos. The original analytical theory of the motion of the satellites was used and the data set was wider than in similar papers of other authors. Thus, a new specified model of the motion of Mars' satellites has been constructed.

  13. Observable quantities in satellite gradiometry

    NASA Astrophysics Data System (ADS)

    Vermeer, Martin

    1990-12-01

    It is shown that, even in the presence of small attitude uncertainties, the gravitational gradient tensor actually has three independent invariants, instead of the two found by Sacerdote and Sanso (1989) and Holota (1988). It is also shown that the influence of angular rotation on gradiometric measurements can be eliminated by using the first differences of the measurement time series obtained. This also reauires the extraction of the angular acceleration rate from the sensor measurements. The adaptation of this technique to the planar sensor array proposed for Aristoteles is examined.

  14. NPP: Why Another Earth-Observing Satellite?

    NASA Video Gallery

    NPP will soon be NASA's newest Earth-observing satellite. To showcase how NPP will be used for both understanding the health of our planet now -- as well as how things might change in the future --...

  15. AMOS Galaxy 15 Satellite Observations and Analysis

    NASA Astrophysics Data System (ADS)

    Hall, D.

    2011-09-01

    In early April 2010, the Galaxy 15 geosynchronous satellite experienced an on-orbit anomaly. Even though the satellite's transmitters and articulating solar panel were still functioning, ground controllers lost the ability to command and maneuver the satellite. With its orbital position no longer maintained, Galaxy 15 began to drift eastward. This forced several other satellites to make collision avoidance maneuvers during the following months. Soon after the initial anomaly, Galaxy 15's operators predicted that the satellite’s reaction wheels would eventually become saturated, causing a loss of both spacecraft attitude and proper sunward orientation of the solar panels. This "off-pointing" event finally occurred in late December, ultimately leading to a depletion of Galaxy 15's batteries. This near-death experience had a fortunate side effect, however, in that it forced the satellite’s command unit to reboot and once again be able to both receive and execute ground commands. The satellite operators have since recovered control of the satellite. AMOS conducted non-resolved photometric observations of Galaxy 15 before, during and after these events. Similar observations were conducted of Galaxy 12, the nearly-identical replacement satellite. This presentation presents and discusses these temporal brightness signatures in detail, comparing the changing patterns in the observations to the known sequence of events.

  16. Observing storm surges from satellite altimetry

    NASA Astrophysics Data System (ADS)

    Han, Guoqi

    2016-07-01

    Storm surges can cause catastrophic damage to properties and loss of life in coastal communities. Thus it is important to enhance our capabilities of observing and forecasting storm surges for mitigating damage and loss. In this presentation we show examples of observing storm surges around the world using nadir satellite altimetry, during Hurricane Sandy, Igor, and Isaac, as well as other cyclone events. The satellite observations are evaluated against tide-gauge observations and discussed for dynamic mechanisms. We also show the potential of a new wide-swath altimetry mission, the Surface Water and Ocean Topography (SWOT), for observing storm surges.

  17. Magnetopause structure from satellite observations

    NASA Technical Reports Server (NTRS)

    Sonnerup, B. U. O.

    1979-01-01

    Observations on magnetopause structure are reported. Major topics covered include: classical reconnection, transport mechanisms, magnetospheric boundary layers, tearing modes, and Jupiter's magnetopause.

  18. Terrestrial Observations from NOAA Operational Satellites.

    PubMed

    Yates, H; Strong, A; McGinnis, D; Tarpley, D

    1986-01-31

    Important applications to oceanography, hydrology, and agriculture have been developed from operational satellites of the National Oceanic and Atmospheric Administration and are currently expanding rapidly. Areas of interest involving the oceans include sea surface temperature, ocean currents, and ocean color. Satellites can monitor various hydrological phenomena, including regional and global snow cover, river and sea ice extent, and areas of global inundation. Agriculturally important quantities derived from operational satellite observations include precipitation, daily temperature extremes, canopy temperatures, insolation, and snow cover. This overview describes the current status of each area.

  19. Observations of the Satellites of Uranus

    NASA Astrophysics Data System (ADS)

    Vieira-Martins, R.; Veiga, C. H.; Lazzaro, D.

    1987-05-01

    ABSTRACT. Since 1982 we have been carrying out observations of the five main satellites of Uranus with the 1.6 meter telescope of the Laborat6- rio Nacional de Astrofisica (Veiga 1986). The satellite positions were measured on photographic plates using a reference system with FK4 stars, and these positions were compared with those calculated using the orbital parameters published by Dunham (1971), Veillet (1983), and Jacobson (1985). The residuals were analyzed considering more elaborate dynamical models, i.e., those with secular, long period and short period variations of the orbital parameters (Dermott et al. 1985; Laskar 1986; Lazzaro et al. 1986). : PLANETS AND SATELLITES

  20. Operational Applications of Satellite Snowcover Observations

    NASA Technical Reports Server (NTRS)

    Rango, A. (Editor); Peterson, R. (Editor)

    1980-01-01

    The history of remote sensing of snow cover is reviewed and the following topics are covered: various techniques for interpreting LANDSAT and NOAA satellite data; the status of future systems for continuing snow hydrology applications; the use of snow cover observations in streamflow forecasts by Applications Systems Verification and Transfer participants and selected foreign investigators; and the benefits of using satellite snow cover data in runoff prediction.

  1. Interferometric observations of an artificial satellite.

    NASA Technical Reports Server (NTRS)

    Preston, R. A.; Ergas, R.; Hinteregger, H. F.; Knight, C. A.; Robertson, D. S.; Shapiro, I. I.; Whitney, A. R.; Rogers, A. E. E.; Clark, T. A.

    1972-01-01

    Very-long-baseline interferometric observations of radio signals from the TACSAT synchronous satellite, even though extending over only 7 hours, have enabled an excellent orbit to be deduced. Precision in differential delay and delay-rate measurements reached 0.15 nanosecond and 0.05 picosecond per second, respectively. The results from this initial three-station experiment demonstrate the feasibility of using the method for accurate satellite tracking and for geodesy.

  2. Feedback Loop of Data Infilling Using Model Result of Actual Evapotranspiration from Satellites and Hydrological Model

    NASA Astrophysics Data System (ADS)

    Murdi Hartanto, Isnaeni; Alexandridis, Thomas K.; van Andel, Schalk Jan; Solomatine, Dimitri

    2014-05-01

    Using satellite data in a hydrological model has long been occurring in modelling of hydrological processes, as a source of low cost regular data. The methods range from using satellite products as direct input, model validation, and data assimilation. However, the satellite data frequently face the missing value problem, whether due to the cloud cover or the limited temporal coverage. The problem could seriously affect its usefulness in hydrological model, especially if the model uses it as direct input, so data infilling becomes one of the important parts in the whole modelling exercise. In this research, actual evapotranspiration product from satellite is directly used as input into a spatially distributed hydrological model, and validated by comparing the catchment's end discharge with measured data. The instantaneous actual evapotranspiration is estimated from MODIS satellite images using a variation of the energy balance model for land (SEBAL). The eight-day cumulative actual evapotranspiration is then obtained by a temporal integration that uses the reference evapotranspiration calculated from meteorological data [1]. However, the above method cannot fill in a cell if the cell is constantly having no-data value during the eight-day periods. The hydrological model requires full set of data without no-data cells, hence, the no-data cells in the satellite's evapotranspiration map need to be filled in. In order to fills the no-data cells, an output of hydrological model is used. The hydrological model is firstly run with reference evapotranspiration as input to calculate discharge and actual evapotranspiration. The no-data cells in the eight-day cumulative map from the satellite are then filled in with the output of the first run of hydrological model. The final data is then used as input in a hydrological model to calculate discharge, thus creating a loop. The method is applied in the case study of Rijnland, the Netherlands where in the winter, cloud cover is

  3. First optical observations of artificial Earth's satellites

    NASA Astrophysics Data System (ADS)

    Rykhlova, L. V.

    2008-08-01

    A review of the first optical observations of the artificial satellites in the USSR as well as in former communist countries (DDR, Romania,Poland) is given. The role by Alla G. Masevich, I.D. Zhongolovich and Yu.V. Batrakov is underlined in the organization of observations.

  4. Global canopy interception from satellite observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new methodology for retrieving rainfall interception rates from multi satellite observations is presented. The approach makes use of the daily productof the Global Precipitation Climatology Project (GPCP) as driving data and applies Gash’s analytical model to derive interception rates at global sc...

  5. Comparison of filter predictions with satellite observations

    SciTech Connect

    Canavan, G.H.

    1997-10-01

    Satellite observations of meteor entry are used to calibrate a filter model of fragmentation. Predicted sizes and masses compare favorably with data and analytic interpretations for objects of all sizes. However, objects that fragment into many large objects should be treated by the decomposition of the radiation signal into the contributions from the different fragments.

  6. Interferometric observations of an artificial satellite.

    PubMed

    Preston, R A; Ergas, R; Hinteregger, H F; Knight, C A; Robertson, D S; Shapiro, I I; Whitney, A R; Rogers, A E; Clark, T A

    1972-10-27

    Very-long-baseline interferometric observations of radio signals from the TACSAT synchronous satellite, even though extending over only 7 hours, have enabled an excellent orbit to be deduced. Precision in differenced delay and delay-rate measurements reached 0.15 nanosecond ( approximately 5 centimeters in equivalent differenced distance) and 0.05 picosecond per second ( approximately 0.002 centimeter per second in equivalent differenced velocity), respectively. The results from this initial three-station experiment demonstrate the feasibility of using the method for accurate satellite tracking and for geodesy. Comparisons are made with other techniques.

  7. Scheduling Earth Observing Satellites with Evolutionary Algorithms

    NASA Technical Reports Server (NTRS)

    Globus, Al; Crawford, James; Lohn, Jason; Pryor, Anna

    2003-01-01

    We hypothesize that evolutionary algorithms can effectively schedule coordinated fleets of Earth observing satellites. The constraints are complex and the bottlenecks are not well understood, a condition where evolutionary algorithms are often effective. This is, in part, because evolutionary algorithms require only that one can represent solutions, modify solutions, and evaluate solution fitness. To test the hypothesis we have developed a representative set of problems, produced optimization software (in Java) to solve them, and run experiments comparing techniques. This paper presents initial results of a comparison of several evolutionary and other optimization techniques; namely the genetic algorithm, simulated annealing, squeaky wheel optimization, and stochastic hill climbing. We also compare separate satellite vs. integrated scheduling of a two satellite constellation. While the results are not definitive, tests to date suggest that simulated annealing is the best search technique and integrated scheduling is superior.

  8. Volcanic iodine monoxide observed from satellite

    NASA Astrophysics Data System (ADS)

    Schönhardt, Anja; Richter, Andreas; Theys, Nicolas; Burrows, John P.

    2016-04-01

    Halogen species are injected into the atmosphere by volcanic eruptions. Previous studies have reported observations of chlorine and bromine oxides in volcanic plumes. These emissions have a significant impact on the chemistry within the plume as well as on upper troposphere and lower stratosphere composition, e.g. through ozone depletion. Volcanic halogen oxides have been observed from different platforms, from ground, aircraft and from satellite. The present study reports on satellite observations of iodine monoxide, IO, following the eruption of the Kasatochi volcano, Alaska, in August 2008. Satellite measurements from the SCIAMACHY sensor onboard ENVISAT are used. In addition, the volcanic IO plume is also retrieved from GOME-2 / MetOP-A measurements. Largest IO column amounts reach up to more than 4×1013 molec/cm2, the results from both instruments being consistent. The IO plume has a very similar shape as the BrO plume and is observed for several days following the eruption. The present observations are the first evidence that besides chlorine and bromine oxides also iodine oxides can be emitted by volcanic eruptions. This has important implications for atmospheric composition and background iodine levels. Together with the simultaneous observations of BrO and SO2, iodine monoxide columns can possibly provide insights into the composition of the magma.

  9. Global Warming: Evidence from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.

    2001-01-01

    Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown on-board sequential, sun-synchronous, polar orbiting NOAA operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study we have minimized systematic errors in the time series introduced by the satellite orbital drift in an objective manner. This is done with the help the onboard warm black body temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically weighted global mean temperature of the atmosphere, with a peak weight near the mid-troposphere, warmed at the rate of 0.13 K per decade (with an uncertainty of 0.05 K per decade) during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite deuced result.

  10. Global Warming: Evidence from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R.; Yoo, J.-M.; Dalu, G.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown onboard sequential, sun-synchronous, polar-orbiting NOAA (National Oceanic and Atmospheric Administration) operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study, we have minimized systematic errors in the time series introduced by satellite orbital drift in an objective manner. This is done with the help of the onboard warm-blackbody temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically-weighted global-mean temperature of the atmosphere, with a peak weight near the mid troposphere, warmed at the rate of 0.13 +/- 0.05 K/decade during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite-deduced result.

  11. Globally Gridded Satellite observations for climate studies

    USGS Publications Warehouse

    Knapp, K.R.; Ansari, S.; Bain, C.L.; Bourassa, M.A.; Dickinson, M.J.; Funk, C.; Helms, C.N.; Hennon, C.C.; Holmes, C.D.; Huffman, G.J.; Kossin, J.P.; Lee, H.-T.; Loew, A.; Magnusdottir, G.

    2011-01-01

    Geostationary satellites have provided routine, high temporal resolution Earth observations since the 1970s. Despite the long period of record, use of these data in climate studies has been limited for numerous reasons, among them that no central archive of geostationary data for all international satellites exists, full temporal and spatial resolution data are voluminous, and diverse calibration and navigation formats encumber the uniform processing needed for multisatellite climate studies. The International Satellite Cloud Climatology Project (ISCCP) set the stage for overcoming these issues by archiving a subset of the full-resolution geostationary data at ~10-km resolution at 3-hourly intervals since 1983. Recent efforts at NOAA's National Climatic Data Center to provide convenient access to these data include remapping the data to a standard map projection, recalibrating the data to optimize temporal homogeneity, extending the record of observations back to 1980, and reformatting the data for broad public distribution. The Gridded Satellite (GridSat) dataset includes observations from the visible, infrared window, and infrared water vapor channels. Data are stored in Network Common Data Format (netCDF) using standards that permit a wide variety of tools and libraries to process the data quickly and easily. A novel data layering approach, together with appropriate satellite and file metadata, allows users to access GridSat data at varying levels of complexity based on their needs. The result is a climate data record already in use by the meteorological community. Examples include reanalysis of tropical cyclones, studies of global precipitation, and detection and tracking of the intertropical convergence zone.

  12. Observation of solid precipitation using satellite gravity

    NASA Astrophysics Data System (ADS)

    Seo, K.; Waliser, D. E.; Ryu, D.; Tian, B.; Kim, B.

    2009-12-01

    Understanding hydrological processes in the arctic region and their variation are emerging and important issues in the association with global climate changes. Solid precipitation is particularly important because it plays a major role in controlling the winter hydrological cycle and spring discharge. Nevertheless, observations of winter snowfall in high latitudes is challenging due to sharply decreasing numbers of precipitation gauges and gauge measurement biases. In addition, conventional satellite methods that work well in low-latitudes are unsuitable for the high latitude conditions. In this study, we present a new method of estimating winter snowfall in the arctic region with GRACE time varying gravity measurements. In northern high latitudes, it is very cold in winter, and thus solid precipitation accumulates with very limited melting and evapotranspiration. Therefore, observed gravity increments during winter mainly result from solid precipitation. We estimate amount of solid precipitation during winter (DJF) from four major arctic basins, Mackenzie, Lena, Yenisei and Ob. New estimates using satellite gravity are compared to global satellite and reanalysis precipitation products , which are GPCP, CMAP, NCEP/NCAR, ECMWF and JCDAS. GRACE-based estimates of snowfall are very close to those of CMAP, ECMWF and JCDAS. We extend the methodology to examine spatial distribution of solid precipitation in the pan-arctic land areas, which shows a good agreement with JCDAS. This new measurement of solid precipitation can provide an altogether new form of observations for hydrological cycle research studies, model and precipitation product evaluation and data assimilation efforts.

  13. Earth observing satellite plans in India

    NASA Astrophysics Data System (ADS)

    Rajan, Y. S.; Behera, G.; Gupta, A. K.; Manikiam, B.

    One of the major objectives of the Indian Space Programme is to develop, launch and operate earth observing satellites to cater to the data needs of the remote sensing user community. Towards this, development of suitable multispectral sensors through satellites and aircraft have played a crucial role. The Rohini and Bhaskara satellites launched during early 1980's provided the base for further development. Presently the first of a series of Remote Sensing satellites, IRS-1A is in orbit and is providing data. The necessary expertise to utilise the remotely sensed data was developed through a set of application projects under Indian Remote Sensing Satellite - Utilisation Programme (IRS-UP) and Remote Sensing Application Mission (RSAM) being carried out with active collaboration of several Central/State user departments/agencies. The application projects cover several themes such as agriculture, water resources, forestry, soil, marine resources etc. in addition to natural calamities such as flood and drought. The IRS-UP projects initiated in 1983, has helped in developing several methodology packages for operational utilisation of remote sensing for natural resources monitoring. Nationwide projects such as Wasteland Mapping, Drinking Water Technology Mission etc. have remote sensing as a major input. Towards ensuring requisite infrastructure and facility, 5 Regional Remote Sensing Service Centres are being operationalised with VAX-11/780 computer based image processing system, in addition to setting up of remote sensing centres in each State/Union Territory. The training of adequate manpower has been another area of attention. The country is poised to reap the advantages of remote sensing technology towards its development.

  14. The NOAA Satellite Observing System Architecture Study

    NASA Technical Reports Server (NTRS)

    Volz, Stephen; Maier, Mark; Di Pietro, David

    2016-01-01

    NOAA is beginning a study, the NOAA Satellite Observing System Architecture (NSOSA) study, to plan for the future operational environmental satellite system that will follow GOES and JPSS, beginning about 2030. This is an opportunity to design a modern architecture with no pre-conceived notions regarding instruments, platforms, orbits, etc. The NSOSA study will develop and evaluate architecture alternatives to include partner and commercial alternatives that are likely to become available. The objectives will include both functional needs and strategic characteristics (e.g., flexibility, responsiveness, sustainability). Part of this study is the Space Platform Requirements Working Group (SPRWG), which is being commissioned by NESDIS. The SPRWG is charged to assess new or existing user needs and to provide relative priorities for observational needs in the context of the future architecture. SPRWG results will serve as input to the process for new foundational (Level 0 and Level 1) requirements for the next generation of NOAA satellites that follow the GOES-R, JPSS, DSCOVR, Jason-3, and COSMIC-2 missions.

  15. Satellite Observations From the International Polar Year

    NASA Astrophysics Data System (ADS)

    Jezek, Kenneth; Drinkwater, Mark

    2010-04-01

    To realize the benefit of the growing number of international satellites to the scientific objectives of the 2007-2008 International Polar Year (IPY), the Global Interagency IPY Polar Snapshot Year (GIIPSY) was established in November 2005 to develop a consensus on polar science requirements and objectives for IPY that could best and perhaps only be met using the Earth-observing satellites. Requirements focused on all aspects of the cryosphere and ranged from sea ice and ice sheets to permafrost and snow cover. Individual topics included how best to develop high-resolution digital elevation models of outlet glaciers using stereo-optical systems, measure ice sheet surface velocity using interferometric synthetic aperture radar (InSAR), and repeatedly measure sea ice motion using optical and microwave imaging instruments. Because of this foresight, several IPY science objectives were well met using satellite observations, allowing a wealth of valuable data to be collected on cryospheric processes (Figure 1). Further, the framework for coordinating these remote sensing efforts serves as a valuable model for future coordinated efforts to monitor cryospheric dynamics.

  16. Satellite observations of transionospheric pulse pairs

    SciTech Connect

    Holden, D.N.; Munson, C.P.; Devenport, J.C.

    1995-04-15

    The BLACKBEARD payload aboard the ALEXIS satellite has been making broadband observations in the VHF band of the radio spectrum. Since November of 1993 several hundred unusual signals have been recorded. The peculiar nature of these bursts of radio noise is that they have a duration of approximately 10 {mu}sec, are typically 20 to 40 dB brighter than the average background, and occur in pairs separated by approximately 50 {mu}sec. The authors have dubbed these emissions TransIonospheric Pulse Pairs, or TIPP events. They do not know what the source of these emissions is, but the dispersion of these signals is consistent with an origin at or near the earth`s surface. The satellite field of view and time of day when TIPP events are generally detected are consistent with regions of thunderstorm activity such as south-central Africa or Indonesia. 4 refs., 5 figs.

  17. Apparent and Actual Use of Observational Frameworks by Experienced Teachers.

    ERIC Educational Resources Information Center

    Satern, Miriam N.

    This study investigated observational strategies that were used by six experienced physical education teachers when viewing a videotape of motor skills (standing vertical jump, overarm throw, tennis serve, basketball jump shot and dance sequence). Four observational frameworks were proposed as being representative of subdisciplinary knowledge…

  18. Operational evapotranspiration based on Earth observation satellites

    NASA Astrophysics Data System (ADS)

    Gellens-Meulenberghs, Françoise; Ghilain, Nicolas; Arboleda, Alirio; Barrios, Jose-Miguel

    2016-04-01

    Geostationary satellites have the potential to follow fast evolving atmospheric and Earth surface phenomena such those related to cloud cover evolution and diurnal cycle. Since about 15 years, EUMETSAT has set up a network named 'Satellite Application Facility' (SAF, http://www.eumetsat.int/website/home/Satellites/GroundSegment/Safs/index.html) to complement its ground segment. The Land Surface Analysis (LSA) SAF (http://landsaf.meteo.pt/) is devoted to the development of operational products derived from the European meteorological satellites. In particular, an evapotranspiration (ET) product has been developed by the Royal Meteorological Institute of Belgium. Instantaneous and daily integrated results are produced in near real time and are freely available respectively since the end of 2009 and 2010. The products cover Europe, Africa and the Eastern part of South America with the spatial resolution of the SEVIRI sensor on-board Meteosat Second Generation (MSG) satellites. The ET product algorithm (Ghilain et al., 2011) is based on a simplified Soil-Vegetation-Atmosphere transfer (SVAT) scheme, forced with MSG derived radiative products (LSA SAF short and longwave surface fluxes, albedo). It has been extensively validated against in-situ validation data, mainly FLUXNET observations, demonstrating its good performances except in some arid or semi-arid areas. Research has then been pursued to develop an improved version for those areas. Solutions have been found in reviewing some of the model parameterizations and in assimilating additional satellite products (mainly vegetation indices and land surface temperature) into the model. The ET products will be complemented with related latent and sensible heat fluxes, to allow the monitoring of land surface energy partitioning. The new algorithm version should be tested in the LSA-SAF operational computer system in 2016 and results should become accessible to beta-users/regular users by the end of 2016/early 2017. In

  19. Development and characterization of Carbon Observing Satellite

    NASA Astrophysics Data System (ADS)

    Zhang, Hang; Lin, Chao; Zheng, Yuquan; Wang, Wenquan; Tian, Longfei; Liu, Dongbin; Li, Shuai

    2016-04-01

    Carbon Observing Satellite (Tan-Sat) is the first satellite of China designed to monitor column-averaged atmospheric carbon dioxide (X) by detecting gas absorption spectra of the solar shortwave infrared radiation reflected from the Earth's surface and atmosphere. Two instruments are accommodated on Tan-Sat: the high resolution hyperspectral sensor for carbon observation grating spectrometer (HRHS-GS) and the cloud and aerosol polarimetric imager (CAPI). HRHS-GS will provide the space-based measurements of CO2 on a scale and with the accuracy and precision to quantify terrestrial sources and sinks of CO2. CAPI is used to identify the contamination by optically thick clouds and to minimize the impact of scattering by aerosol. These two instruments work together to collect global column CO2 concentrations with correction for cloud and aerosol contamination. The instrument design of HRHS-GS is presented. Ocean reflectivity and the incident radiation of the instrument for transverse electric and transverse magnetic polarizations in glint mode are discussed. The changes to glint mode operation are described. The spectral characteristics of HRHS-GS were determined through the laser-based spectral calibration. The onboard spectral calibration method based on spectrum matching is introduced. The availability was verified, satisfying the onboard spectral calibration accuracy requirement of better than Δλ/10 (Δλ is spectral resolution).

  20. Decadal Record of Satellite Carbon Monoxide Observations

    NASA Astrophysics Data System (ADS)

    Worden, Helen; Deeter, Merritt; Frankenberg, Christian; George, Maya; Nichitiu, Florian; Worden, John; Aben, Ilse; Bowman, Kevin; Clerbaux, Cathy; Coheur, Pierre-Francois; de Laat, Jos; Warner, Juying; Drummond, James; Edwards, David; Gille, John; Hurtmans, Daniel; Ming, Luo; Martinez-Alonso, Sara; Massie, Steven; Pfister, Gabriele

    2013-04-01

    Atmospheric carbon monoxide (CO) distributions are controlled by anthropogenic emissions, biomass burning, chemical production, transport and oxidation by reaction with the hydroxyl radical (OH). Quantifying trends in CO is therefore important for understanding changes related to all of these contributions. Here we present a comprehensive record of satellite observations from 2000 through 2011 of total column CO using the available measurements from nadir-viewing thermal infrared instruments: MOPITT, AIRS, TES and IASI. We examine trends for CO in the Northern and Southern hemispheres along with regional trends for E. China, E. USA, Europe and India. Measurement and sampling methods for each of the instruments are discussed, and we show diagnostics for systematic errors in MOPITT trends. We find that all the satellite observations are consistent with a modest decreasing trend around -1%/year in total column CO over the Northern hemisphere for this time period. Decreasing trends in total CO column are observed for the United States, Europe and E. China with more than 2σ significance. For India, the trend is also decreasing, but smaller in magnitude and less significant. Decreasing trends in surface CO have also been observed from measurements in the U.S. and Europe. Although less information is available for surface CO in China, there is a decreasing trend reported for Beijing. Some of the interannual variability in the observations can be explained by global fire emissions, and there may be some evidence of the global financial crisis in late 2008 to early 2009. But the overall decrease needs further study to understand the implications for changes in anthropogenic emissions.

  1. Commercial observation satellites: broadening the sources of geospatial data

    NASA Astrophysics Data System (ADS)

    Baker, John C.; O'Connell, Kevin M.; Venzor, Jose A.

    2002-09-01

    Commercial observation satellites promise to broaden substantially the sources of imagery data available to potential users of geospatial data and related information products. We examine the new trend toward private firms acquiring and operating high-resolution imagery satellites. These commercial observation satellites build on the substantial experience in Earth observation operations provided by government-owned imaging satellites for civilian and military purposes. However, commercial satellites will require governments and companies to reconcile public and private interests in allowing broad public access to high-resolution satellite imagery data without creating national security risks or placing the private firms at a disadvantage compared with other providers of geospatial data.

  2. Estimating Soil Moisture from Satellite Microwave Observations

    NASA Technical Reports Server (NTRS)

    Owe, M.; VandeGriend, A. A.; deJeu, R.; deVries, J.; Seyhan, E.

    1998-01-01

    Cooperative research in microwave remote sensing between the Hydrological Sciences Branch of the NASA Goddard Space Flight Center and the Earth Sciences Faculty of the Vrije Universiteit Amsterdam began with the Botswana Water and Energy Balance Experiment and has continued through a series of highly successful International Research Programs. The collaboration between these two research institutions has resulted in significant scientific achievements, most notably in the area of satellite-based microwave remote sensing of soil moisture. The Botswana Program was the first joint research initiative between these two institutions, and provided a unique data base which included historical data sets of Scanning Multifrequency Microwave Radiometer (SN4NM) data, climate information, and extensive soil moisture measurements over several large experimental sites in southeast Botswana. These data were the basis for the development of new approaches in physically-based inverse modelling of soil moisture from satellite microwave observations. Among the results from this study were quantitative estimates of vegetation transmission properties at microwave frequencies. A single polarization modelling approach which used horizontally polarized microwave observations combined with monthly composites of Normalized Difference Vegetation Index was developed, and yielded good results. After more precise field experimentation with a ground-based radiometer system, a dual-polarization approach was subsequently developed. This new approach realized significant improvements in soil moisture estimation by satellite. Results from the Botswana study were subsequently applied to a desertification monitoring study for the country of Spain within the framework of the European Community science research programs EFEDA and RESMEDES. A dual frequency approach with only microwave data was used for this application. The Microwave Polarization Difference Index (MPDI) was calculated from 37 GHz data

  3. NASA Now: Orbital Mechanics: Earth Observing Satellites

    NASA Video Gallery

    This NASA Now program is all about satellites and their orbits. Dr. James Gleason, project scientist for NPP, explains what it takes for a satellite to stay in orbit, why there are different types ...

  4. Cloudsat and MTSAT Satellites Observer Atsani

    NASA Video Gallery

    This Aug. 19 image combines cloud imagery from Japan's MTSAT satellite and NASA's CloudSat satellite. Areas of pink and red designate larger amounts of liquid and ice. Light blue indicate smaller c...

  5. ASTER satellite observations for international disaster management

    USGS Publications Warehouse

    Duda, K.A.; Abrams, M.

    2012-01-01

    When lives are threatened or lost due to catastrophic disasters, and when massive financial impacts are experienced, international emergency response teams rapidly mobilize to provide urgently required support. Satellite observations of affected areas often provide essential insight into the magnitude and details of the impacts. The large cost and high complexity of developing and operating satellite flight and ground systems encourages international collaboration in acquiring imagery for such significant global events in order to speed delivery of critical information to help those affected, and optimize spectral, spatial, and temporal coverage of the areas of interest. The International Charter-Space and Major Disasters was established to enable such collaboration in sensor tasking during times of crisis and is often activated in response to calls for assistance from authorized users. Insight is provided from a U.S. perspective into sensor support for Charter activations and other disaster events through a description of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), which has been used to support emergency situations for over a decade through its expedited tasking and near real-time data delivery capabilities. Examples of successes achieved and challenges encountered in international collaboration to develop related systems and fulfill tasking requests suggest operational considerations for new missions as well as areas for future enhancements.

  6. Satellite Observations of the Epic California Drought

    NASA Astrophysics Data System (ADS)

    Famiglietti, J. S.; Thomas, B. F.; Reager, J. T., II; Castle, S. L.; David, C. H.; Thomas, A. C.; Andreadis, K.; Argus, D. F.; Behrangi, A.; Farr, T.; Fisher, J. B.; Landerer, F. W.; Lo, M. H.; Molotch, N. P.; Painter, T. H.; Rodell, M.; Schimel, D.; Swenson, S. C.; Watkins, M. M.

    2014-12-01

    As California enters its third year of drought, questions of future water sustainability are inevitable. Snowpack, soil moisture, streamflow, reservoir and groundwater levels are at record lows. Mandatory water restrictions are being implemented, statewide fines for wasting water have been authorized, and billions of dollars and tens of thousands of jobs have been lost. Enhanced monitoring and modeling of the state's dwindling water supplies can help manage what remains while looking forward to a post-drought, sustainable water future. Here we demonstrate the role of satellite observations in comprehensive drought characterization and monitoring. In particular we highlight changing water supply, declining groundwater and reservoir levels, agricultural and urban stress. Potential contributions to water management will be discussed.

  7. Satellite observation of atmospheric nuclear gamma radiation

    NASA Technical Reports Server (NTRS)

    Letaw, John R.; Share, G. H.; Kinzer, R. L.; Silberberg, R.; Chupp, E. L.

    1989-01-01

    Satellite observations of the spectrum of gamma radiation from the earth's atmosphere in the energy interval from 300 keV to 8.5 MeV were obtained with a gamma-ray spectrometer during 1980-1983. A total of 20 atmospheric line features are superimposed on a continuum background which is modeled using a power law with an index of -1.16. The line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric N-14 and O-16. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, are explained by Compton scattering of the annihilation line photons in traversing an average of 21 g/sq cm of atmosphere.

  8. Industrial use of land observation satellite systems

    NASA Technical Reports Server (NTRS)

    Henderson, F. B., III

    1984-01-01

    The principal industrial users of land observation satellite systems are the geological industries; oil/gas, mining, and engineering/environmental companies. The primary system used is LANDSAT/MSS. Currently, use is also being made of the limited amounts of SKYLAB photography, SEASAT and SIR-A radar, and the new LANDSAT/TM data available. Although considered experimental, LANDSAT data is now used operationally by several hundred exploration and engineering companies worldwide as a vastly improved geological mapping tool to help direct more expensive geophysical and drilling phases, leading to more efficient decision-making and results. Future needs include global LANDSAT/TM; higher spatial resolution; stereo and radar; improved data handling, processing distribution and archiving systems, and integrated geographical information systems (GIS). For a promising future, governments must provide overall continuity (government and/or private sector) of such systems, insure continued government R and D, and commit to operating internationally under the civil Open Skies policy.

  9. Arctic Warming Signals from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.

    2005-01-01

    Global warming signals are expected to be amplified in the Arctic primarily because of ice-albedo feedback associated with the high reflectivity of ice and snow that blankets much of the region. The Arctic had been a poorly explored territory basically because of its general inaccessibility on account of extremely harsh weather conditions and the dominant presence of thick perennial ice in the region. The advent of satellite remote sensing systems since the 1960s, however, enabled the acquisition of synoptic data that depict in good spatial detail the temporal changes of many Arctic surface parameters. Among the surface parameters that have been studied using space based systems are surface temperature, sea ice concentration, snow cover, surface albedo and phytoplankton concentration. Associated atmospheric parameters, such as cloud cover, temperature profile, ozone concentration, and aerosol have also been derived. Recent observational and phenomenological studies have indeed revealed progressively changing conditions in the Arctic during the last few decades (e g , Walsh et al. 1996; Serreze et al 2000; Comiso and Parkinson 2004). The changes included declines in the extent and area of surfaces covered by sea ice and snow, increases in melt area over the Greenland ice sheets, thawing of the permafrost, warming in the troposphere, and retreat of the glaciers. These observations are consistent with the observed global warming that has been associated with the increasing concentration of greenhouse gases in the atmosphere (Karl and Trenberth 2003) and confirmed by modeling studies (Holland and Bitz, 2003). The Arctic system, however, is still not well understood complicated by a largely fluctuating wind circulation and atmospheric conditions (Proshutinsky and Johnson 1997) and controlled by what is now known as the Arctic Oscillation (AO) which provides a measure of the strength of atmospheric activities in the region (Thompson and Wallace 1998). Meanwhile, the

  10. Global Precipitation Analysis Using Satellite Observations

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Huffman, George; Curtis, Scott; Bolvin, David; Nelkin, Eric

    2002-01-01

    Global precipitation analysis covering the last few decades and the impact of the new TRMM (Tropical Rainfall Measuring Mission) observations are reviewed in the context of weather and climate applications. All the data sets discussed are the result of mergers of information from multiple satellites and gauges, where available. The focus of the talk is on TRMM-based 3 hr. analyses that use TRMM to calibrate polar-orbit microwave observations from SSM/I (and other satellites) and geosynchronous IR observations and merges the various calibrated observations into a final, 3 hr. resolution map. This TRMM standard product will be available for the entire TRMM period (January 1998-present) at the end of 2002. A real-time version of this merged product is being produced and is available at 0.25 deg latitude-longitude resolution over the latitude range from 50 deg N-50 deg S. Examples will be shown, including its use in monitoring flood conditions and in relating weather-scale patterns to climate-scale patterns. The 3-hourly analysis is placed in the context of two research products of the World Climate Research Program's (WCRP/GEWEX) Global Precipitation Climatology Project (GPCP). The first is the 23 year, monthly, globally complete precipitation analysis that is used to explore global and regional variations and trends and is compared to the much shorter TRMM tropical data set. The GPCP data set shows no significant global trend in precipitation over the twenty years, unlike the positive trend in global surface temperatures over the past century. Regional trends are also analyzed. A trend pattern that is a combination of both El Nino and La Nina precipitation features is evident in the Goodyear data set. This pattern is related to an increase with time in the number of combined months of El Nino and La Nina during the 23 year period. Monthly anomalies of precipitation are related to ENSO variations with clear signals extending into middle and high latitudes of both

  11. Monitoring vegetation using DOAS satellite observations

    NASA Astrophysics Data System (ADS)

    Eigemeier, Ellen; Beirle, Steffen; Marbach, Thierry; Platt, Ulrich; Wagner, Thomas

    2010-05-01

    Vegetation-cycles are of general interest for many applications. Be it for harvest-predictions, global monitoring of climate-change or as input to atmospheric models. From novel spectrally resolving UV/vis satellite instruments (like GOME or SCIAMACHY) the spectral signatures of different types of vegetation can be identified and analysed. Although the spatial resolution of GOME and SCIAMACHY observations is much coarser than those of conventional satellite instruments for vegetation monitoring, our data sets on different vegetation types add new and useful information, not obtainable from other sources. Common vegetation indices are based on the fact that the difference between Red and Near Infrared reflection is higher than in any other material on Earth's surface. This gives a very high degree of confidence for vegetation-detection. The spectrally resolving data from GOME and SCIAMACHY provide the chance to concentrate on finer spectral features throughout the red and near infrared spectrum. We look at these features using a technique known as Differential Optical Absorption Spectroscopy (DOAS). Although originally developed to retrieve information on trace gases, it can also be used to gain information on vegetation. Another advantage is that this method automatically corrects for atmospheric effects. This renders the vegetation-information easily comparable over long time-spans. In addition, high-frequency-structures from vegetation also effect the retrieval of tropospheric trace-gases and aerosols. To optimize vegetation monitoring with DOAS we produce spectrally resolved reference spectra from different vegetation types using our own instrumentation. We analyze the effect of different Pigments on high-frequency-structures of the DOAS Retrieval. Applying these results we investigate how well we can distinguish vegetation types from space.

  12. Monitoring vegetation using DOAS satellite observations

    NASA Astrophysics Data System (ADS)

    Eigemeier, E.; Beirle, S.; Marbach, T.; Platt, U.; Wagner, T.

    2009-04-01

    Vegetation-cycles are of general interest for many applications. Be it for harvest-predictions, global monitoring of climate-change or as input to atmospheric models. From novel spectrally resolving UV/vis satellite instruments (like GOME of SCIAMACHY) the spectral signatures of different types of vegetation can be identified and analysed. Although the spatial resolution of GOME and SCIAMACHY observations is much coarser than those of conventional satellite instruments for vegetation monitoring, our data sets on different vegetation types add new and useful information, not obtainable from other sources. Common Vegetation Indices use the fact that the difference between Red and Near Infrared reflection is higher than in any other material on Earth's surface. This gives a very high degree of confidence for vegetation-detection. The spectrally resolving data from GOME and SCIAMACHY provide the chance to concentrate on finer spectral features throughout the Red and Near Infrared spectrum. We look at these using a technique known as Differential Optical Absorption Spectroscopy (DOAS). Although originally developed to retrieve information on trace gases, it can also be used to gain information on vegetation. Another advantage is that this method automatically corrects for changes in the atmosphere. This renders the vegetation-information easily comparable over long time-spans. In addition, high-frequency-structures from vegetation also effect the retrieval of tropospheric trace-gases and aerosols. To optimize vegetation monitoring with DOAS we produce spectrally resolved reference spectra from different vegetation types. We investigate how well we will be able to distinguish vegetation types from space. This will also be valuable for monitoring global vegetation-cycles over long time spans. Preliminary results will be presented here.

  13. Monitoring vegetation using DOAS satellite observations

    NASA Astrophysics Data System (ADS)

    Eigemeier, E.; Beirle, S.; Marbach, T.; Platt, U.; Wagner, T.

    2009-12-01

    Vegetation-cycles are of general interest for many applications. Be it for harvest-predictions, global monitoring of climate-change or as input to atmospheric models. From novel spectrally resolving UV/vis satellite instruments (like GOME or SCIAMACHY) the spectral signatures of different types of vegetation can be identified and analysed. Although the spatial resolution of GOME and SCIAMACHY observations is much coarser than those of conventional satellite instruments for vegetation monitoring, our data sets on different vegetation types add new and useful information, not obtainable from other sources. Common vegetation indices are based on the fact that the difference between Red and Near Infrared reflection is higher than in any other material on Earth’s surface. This gives a very high degree of confidence for vegetation-detection. The spectrally resolving data from GOME and SCIAMACHY provide the chance to concentrate on finer spectral features throughout the red and near infrared spectrum. We look at these features using a technique known as Differential Optical Absorption Spectroscopy (DOAS). Although originally developed to retrieve information on trace gases, it can also be used to gain information on vegetation. Another advantage is that this method automatically corrects for atmospheric effects. This renders the vegetation-information easily comparable over long time-spans. In addition, high-frequency-structures from vegetation also effect the retrieval of tropospheric trace-gases and aerosols. To optimize vegetation monitoring with DOAS we produce spectrally resolved reference spectra from different vegetation types using our own instrumentation. We analyze the effect of different Pigments on high-frequency-structures of the DOAS Retrieval. Applying these results we investigate how well we can distinguish vegetation types from space.

  14. Solar neutron observations with ChubuSat-2 satellite

    NASA Astrophysics Data System (ADS)

    Yamaoka, Kazutaka

    2016-07-01

    Solar neutron observation is a key in understanding of ion accerelation mechanism in the Sun surface since neutrons are hardly affected by magnetic field around the Sun and intersteller mediums unlike charged particles. However, there was only a few tenth detections so far since its discovery in 1982. Actually SEDA-AP Fiber detector (FIB) onboard the International Space Station (ISS) was suffered from a high neutron background produced by the ISS itself. ChubuSat is a series of 50-kg class microsatellite jointly depeloped by universities (Nagoya university and Daido university) and aerospace companies at the Chubu area of central Japan. The ChubuSat-2 is the second ChubuSat following the ChubuSat-1 which was launched by Russian DNEPR rocket on November 6, 2014. It was selected as one of four piggyback payloads of the X-ray astronomy satellite ASTRO-H in 2014 summer, and will be launched by the H-IIA launch vehcles from from JAXA Tanegashima Space Center (TNSC) in February 2016. The ChubuSat-2 carries a mission instrument, radiation detector (RD). The main mission of ChubuSat-2 is devoted for monitoring neutrons and gamma-rays which can be background source for ASTRO-H celestrial observations with the RD. The mission also involves a function of solar neutron observations which were originally proposed by graduate students who join the leadership development program for space exploration and research, program for leading graduate schools at Nagoya University. The RD has a similar detection area and efficiency to those of the SEDA-AP FIB, but is expected to have lower backgrounthan the ISS thanks to much smaller mass of the micro-satellite. In this paper, we will describe details of ChubuSat-2 satellite and RD, and in-orbit performance of RD.

  15. Satellite observation of atmospheric nuclear gamma radiation.

    PubMed

    Letaw, J R; Share, G H; Kinzer, R L; Silberberg, R; Chupp, E L; Forrest, D J; Rieger, E

    1989-02-01

    We present a satellite observation of the spectrum of gamma radiation from the Earth's atmosphere in the energy interval from 300 keV to 8.5 MeV. The data were accumulated by the gamma ray spectrometer on the Solar Maximum Mission over 3 1/2 years, from 1980 to 1983. The excellent statistical accuracy of the data allows 20 atmospheric line features to be identified. The features are superimposed on a continuum background which is modeled using a power law with index -1.16. Many of these features contain a blend of more than one nuclear line. All of these lines (with the exception of the 511-keV annihilation line) are Doppler broadened. Line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric 14N and 16O. Although we find no evidence for other production mechanisms, we cannot rule out significant contributions from direct excitation or spallation by primary cosmic ray protons. The relative intensities of the observed line features are in fair agreement with theoretical models; however, existing models are limited by the availability of neutron cross sections, especially at high energies. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, can be explained by Compton scattering of the annihilation line photons in traversing an average of approximately 21 g cm-2 of atmosphere.

  16. Satellite observations of ground water changes in New Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2002 NASA launched the Gravity Recovery and Climate Experiment (GRACE) satellite mission. GRACE consists of two satellites with a separation of about 200 km.  By accurately measuring the separation between the twin satellites, the differences in the gravity field can be determined. Monthly observ...

  17. Solar energy microclimate as determined from satellite observations

    NASA Technical Reports Server (NTRS)

    Vonder Haar, T. H.; Ellis, J. S.

    1975-01-01

    A method is presented for determining solar insolation at the earth's surface using satellite broadband visible radiance and cloud imagery data, along with conventional in situ measurements. Conventional measurements are used to both tune satellite measurements and to develop empirical relationships between satellite observations and surface solar insolation. Cloudiness is the primary modulator of sunshine. The satellite measurements as applied in this method consider cloudiness both explicitly and implicitly in determining surface solar insolation at space scales smaller than the conventional pyranometer network.

  18. Satellite observations of a monsoon depression

    NASA Technical Reports Server (NTRS)

    Warner, C.

    1984-01-01

    The exploration of a monsoon depression over Burma and the Bay of Bengal is discussed. Aircraft and satellite data were examined, with an emphasis on the Microwave Sounding Unit (MSU) aboard TIROS-N and the Scanning Multichannel Microwave Radiometer (SMMR) aboard Nimbus-7. The structure of the monsoon depression was found to be dominated by cumulus convection. The only systematic large scale behavior discerned was a propagation of the depression westward, and diurnal migration of contours of brightness temperature. These contours in the middle troposphere showed a gradient toward the north with the patterns migrating northward at night. From SMMR and dropwindsonde data, water vapor contents were found to be near 65 mm, increasing to more than 70 mm in the northeast Bay of Bengal. Cloud water contents reached about three mm. Rainfall rates exceeding 5.7 mm/h occurred over a small part of the storm area, while mean rainfall rates in areas of order 20,000 sq km reached approximately 0.5 mm/h. Measured MSU brightness temperatures were reconciled very well with dropwindsonde data and with airborne in situ observations of clouds (by photography) and hydrometeors (by radar). Diffuse scattering was determined to be important in computing brightness temperature.

  19. Operational Applications of Satellite Snowcover Observations

    NASA Technical Reports Server (NTRS)

    Rango, A. (Editor)

    1975-01-01

    LANDSAT and NOAA satellites data were used to study snow depth. These snow measurements were used to help forecast runoff and flooding. Many areas of California, Arizona, Colorado, and Wyoming were emphasized.

  20. On determining magnetospheric diffusion coefficients from the observed effects of Jupiter's satellite Io

    NASA Technical Reports Server (NTRS)

    Thomsen, M. F.; Goertz, C. K.; Van Allen, J. A.

    1977-01-01

    A method is derived for determining the radial diffusion coefficient from observed satellite effects of the inner Jovian satellites on the energetic particle fluxes. The method is based on data from L values which are significantly removed from the actual sweeping region. With regard to the large losses to the protons at Io's L shell, it is suggested that in addition to satellite sweepup, the losses may be associated with an enhanced precipitation due to resonant interaction with ion cyclotron waves near Io's orbit. It is noted that such additional loss mechanisms may also apply to electrons, and that such losses may significantly affect the estimated diffusion coefficient.

  1. Small Aperture Telescope Observations of Co-located Geostationary Satellites

    NASA Astrophysics Data System (ADS)

    Scott, R.; Wallace, B.

    As geostationary orbit (GEO) continues to be populated, satellite operators are increasing usage of co-location techniques to maximize usage of fewer GEO longitude slots. Co-location is an orbital formation strategy where two or more geostationary satellites reside within one GEO stationkeeping box. The separation strategy used to prevent collision between the co-located satellites generally uses eccentricity (radial separation) and inclination (latitude separation) vector offsets. This causes the satellites to move in relative motion ellipses about each other as the relative longitude drift between the satellites is near zero. Typical separations between the satellites varies from 1 to 100 kilometers. When co-located satellites are observed by optical ground based space surveillance sensors the participants appear to be separated by a few minutes of arc or less in angular extent. Under certain viewing geometries, these satellites appear to visually conjunct even though the satellites are, in fact, well separated spatially. In situations where one of the co-located satellites is more optically reflective than the other, the reflected sunglint from the more reflective satellite can overwhelm the other. This less frequently encountered issue causes the less reflective satellite to be glint masked in the glare of the other. This paper focuses on space surveillance observations on co-located Canadian satellites using a small optical telescope operated by Defence R&D Canada - Ottawa. The two above mentioned problems (cross tagging and glint masking) are investigated and we quantify the results for Canadian operated geostationary satellites. The performance of two line element sets when making in-frame CCD image correlation between the co-located satellites is also examined. Relative visual magnitudes between the co-located members are also inspected and quantified to determine the susceptibility of automated telescopes to glint masking of co-located satellite members.

  2. Satellite observed preferential states in soil moisture

    NASA Astrophysics Data System (ADS)

    Vilasa, Luis U.; De Jeu, Richard A. M.; Dolman, Han A. J.; Wang, Guojie

    2013-04-01

    This study presents observational evidence for the existence of preferential states in soil moisture content. Recently there has been much debate about the existence, location and explanations for preferential states in soil moisture. A number of studies have provided evidence either in support or against the hypothesis of a positive feedback mechanism between soil moisture and subsequent precipitation in certain regions. Researchers who support the hypothesis that preferential states in soil moisture holds information about land atmosphere feedback base their theory on the impact of soil moisture on the evaporation process. Evaporation recycles moisture to the atmosphere and soil moisture has a direct impact on the supply part of this process but also on the partitioning of the available energy for evaporation. According to this theory, the existence of soil moisture bimodality can be used as an indication of possible land-atmosphere feedbacks, to be compared with model simulations of soil moisture feedbacks. On the other hand, other researchers argue that seasonality in the meteorological conditions in combination with the non-linearity of soil moisture response alone can induce bimodality. In this study we estimate the soil moisture bimodality at a global scale as derived from the recently available 30+ year ESA Climate Change Initative satellite soil moisture dataset. An Expectation-Maximization iterative algorithm is used to find the best Gaussian Mixture Model, pursuing the highest likelihood for soil moisture bimodality. With this approach we mapped the regions where bi-modal probability distribution of soil moisture appears for each month for the period between 1979-2010. These bimodality areas are analyzed and compared to maps of model simulations of soil moisture feedbacks. The areas where more than one preferential state exists compare surprisingly well with the map of land-atmosphere coupling strength from model simulations. This approach might

  3. Imaging artificial satellites: An observational challenge

    NASA Astrophysics Data System (ADS)

    Smith, D. A.; Hill, D. C.

    2016-10-01

    According to the Union of Concerned Scientists, as of the beginning of 2016 there are 1381 active satellites orbiting the Earth, and the United States' Space Surveillance Network tracks about 8000 manmade orbiting objects of baseball-size and larger. NASA estimates debris larger than 1 cm to number more than half a million. The largest ones can be seen by eye—unresolved dots of light that move across the sky in minutes. For most astrophotographers, satellites are annoying streaks that can ruin hours of work. However, capturing a resolved image of an artificial satellite can pose an interesting challenge for a student, and such a project can provide connections between objects in the sky and commercial and political activities here on Earth.

  4. Satellite Observations for Detecting and Tracking Changes in Atmospheric Composition

    EPA Science Inventory

    The international scientific community's Integrated Global Atmosphere Chemistry Observation System report outlined a plan for ground-based, airborne and satellite Measurements, and models to integrate the observations into a 4-dimensional representation of the atmosphere (space a...

  5. Surface energy balance and actual evapotranspiration of the transboundary Indus Basin estimated from satellite measurements and the ETLook model

    NASA Astrophysics Data System (ADS)

    Bastiaanssen, W. G. M.; Cheema, M. J. M.; Immerzeel, W. W.; Miltenburg, I. J.; Pelgrum, H.

    2012-11-01

    The surface energy fluxes and related evapotranspiration processes across the Indus Basin were estimated for the hydrological year 2007 using satellite measurements. The new ETLook remote sensing model (version 1) infers information on actual Evaporation (E) and actual Transpiration (T) from combined optical and passive microwave sensors, which can observe the land-surface even under persistent overcast conditions. A two-layer Penman-Monteith equation was applied for quantifying soil and canopy evaporation. The novelty of the paper is the computation of E and T across a vast area (116.2 million ha) by using public domain microwave data that can be applied under all weather conditions, and for which no advanced input data are required. The average net radiation for the basin was estimated as being 112 Wm-2. The basin average sensible, latent and soil heat fluxes were estimated to be 80, 32, and 0 Wm-2, respectively. The average evapotranspiration (ET) and evaporative fraction were 1.2 mm d-1 and 0.28, respectively. The basin wide ET was 496 ± 16.8 km3 yr-1. Monte Carlo analysis have indicated 3.4% error at 95% confidence interval for a dominant land use class. Results compared well with previously conducted soil moisture, lysimeter and Bowen ratio measurements at field scale (R2 = 0.70; RMSE = 0.45 mm d-1; RE = -11.5% for annual ET). ET results were also compared against earlier remote sensing and modeling studies for various regions and provinces in Pakistan (R2 = 0.76; RMSE = 0.29 mmd-1; RE = 6.5% for annual ET). The water balance for all irrigated areas together as one total system in Pakistan and India (26.02 million ha) show a total ET value that is congruent with the ET value from the ETLook surface energy balance computations. An unpublished validation of the same ETLook model for 23 jurisdictional areas covering the entire Australian continent showed satisfactory results given the quality of the watershed data and the diverging physiographic and climatic

  6. Satellite Observed Changes in the Arctic

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.; Parkinson, Claire L.

    2004-01-01

    The Arctic is currently considered an area in transformation. Glaciers have been retreating, permafrost has been diminishing, snow covered areas have been decreasing, and sea ice and ice sheets have been thinning. This paper provides an overview of the unique role that satellite sensors have contributed in the detection of changes in the Arctic and demonstrates that many of the changes are not just local but a pan-Arctic phenomenon. Changes from the upper atmosphere to the surface are discussed and it is apparent that the magnitude of the trends tends to vary from region to region and from season to season. Previous reports of a warming Arctic and a retreating perennial ice cover have also been updated, and results show that changes are ongoing. Feedback effects that can lead to amplification of the signals and the role of satellite data in enhancing global circulation models are also discussed.

  7. The Nimbus satellites - Pioneering earth observers

    NASA Technical Reports Server (NTRS)

    White, Carolynne

    1990-01-01

    The many scientific achievements of the Nimbus series of seven satellites for low-altitude atmospheric research and global weather surveillance are reviewed. The series provides information on fishery resources, weather modeling, atmospheric pollution monitoring, earth's radiation budget, ozone monitoring, ocean dynamics, and the effects of cloudiness. Data produced by the forty-eight instruments and sensors flown on the satellites are applied in the fields of oceanography, hydrology, geology, geomorphology, geography, cartography, agriculture and meteorology. The instruments include the Coastal Zone Color Scanner (which depicts phytoplankton concentrations in coastal areas), the Scanning Multichannel Microwave Radiometer (which measures sea-surface temperatures and sea-surface wind-speed), and the Total Ozone Mapping Spectrometer (which provides information on total amounts of ozone in the earth's atmosphere).

  8. Remote Observation of Volcanos by Small Satellite Formations

    NASA Astrophysics Data System (ADS)

    Schilling, Klaus; Zakšek, Klemen

    2016-07-01

    Volcanic eruptions, severe storms, or desert dust can seriously jeopardize the safety of the air traffic. To prevent encounters of airplanes with such clouds it is necessary to accurately monitor the cloud top heights, which is impossible using currently operational satellites. The most commonly used method for satellite cloud height estimation compares brightness temperature of the cloud with the atmospheric temperature profile. Because of its many uncertainties we propose to exploit the formation of four satellites providing images for photogrammetric analysis. Simultaneous observations from multiple satellites is necessary, because clouds can move with velocities over several m/s. With the proposed mission, we propose a formation of nano-satellites that simultaneously observe the clouds from different positions and orientations. The proposed formation of four satellites will fly in the same orbit with a distance between each satellite of 100 km on the height of 600 km. There are autonomous reaction capabilities realized to focus all satellites on the same surface point for joint observations, enabling by postprocessing 3D surface images. Each satellite will carry a camera operating in visible spectrum providing data with 35 m spatial resolution. Such data will make possible to monitor multilayer clouds with a vertical accuracy of 200 m.

  9. On the development of earth observation satellite systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Subsequent to the launching of the first LANDSAT by NASA, Japan has recognized the importance of data from earth observation satellites, has conducted studies, and is preparing to develop an independent system. The first ocean observation satellite will be launched in 1983, the second in 1985. The first land observation satellite is scheduled to be launched in 1987 and by 1990 Japan intends to have both land and ocean observation systems in regular operation. The association reception and data processing systems are being developed.

  10. Sea surface temperature: Observations from geostationary satellites

    NASA Astrophysics Data System (ADS)

    Bates, John J.; Smith, William L.

    1985-11-01

    A procedure is developed for estimating sea surface temperatures (SST) from multispectral image data acquired from the VISSR atmospheric sounder (VAS) on the geostationary GOES satellites. Theoretical regression equations for two and three infrared window channels are empirically tuned by using clear field of view satellite radiances matched with reports of SST from NOAA fixed environmental buoys from 1982. The empirical regression equations are then used to produce daily regional analyses of SST. The daily analyses are used to study the response of SST's to the passage of Hurricane Alicia (1983) and Hurricane Debbie (1982) and are also used as a first guess surface temperature in the retrieval of atmospheric temperature and moisture profiles over the oceanic regions. Monthly mean SST's for the western North Atlantic and the eastern equatorial Pacific during March and July 1982 were produced for use in the NASA/JPL SST intercomparison workshop series. Workshop results showed VAS SST's have a scatter of 0.8°-1.0°C and a slight warm bias with respect to the other measurements of SST. Subsequently, a second set of VAS/ buoy matches collected during 1983 and 1984 was used to produce a set of bias corrected regression relations for VAS.

  11. Observing Climate with Satellites - Are We on Thin Ice?

    NASA Technical Reports Server (NTRS)

    Tucker, Compton

    2012-01-01

    The Earth s climate is determined by irradiance from the Sun and properties of the atmosphere, oceans, and land that determine the reflection, absorption, and emission of energy within our atmosphere and at the Earth s surface. Since the 1970s, Earth-viewing satellites have complimented non-satellite geophysical observations with consistent, quantitative, and spatially-continuous measurements that have led to an unprecedented understanding of the Earth s climate system. I will describe the Earth s climate system as elaborated by satellite and in situ observations, review arguments against global warming, and show the convergence of evidence for human-caused warming of our planet.

  12. Investigation of mesoscale meteorological phenomena as observed by geostationary satellite

    NASA Technical Reports Server (NTRS)

    Brundidge, K. C.

    1982-01-01

    Satellite imagery plus conventional synoptic observations were used to examine three mesoscale systems recently observed by the GOES-EAST satellite. The three systems are an arc cloud complex (ACC), mountain lee wave clouds and cloud streets parallel to the wind shear. Possible gravity-wave activity is apparent in all three cases. Of particular interest is the ACC because of its ability to interact with other mesoscale phenomena to produce or enhance convection.

  13. Corrective Feedback in L2 Latvian Classrooms: Teacher Perceptions versus the Observed Actualities of Practice

    ERIC Educational Resources Information Center

    Dilans, Gatis

    2016-01-01

    This two-part study aims to investigate teacher perceptions about providing oral corrective feedback (CF) to minority students of Latvian as a second language and compare the perceptions to the actual provision of CF in L2 Latvian classrooms. The survey sample represents sixty-six L2 Latvian teachers while the classroom observations involved 13…

  14. Actual evapotranspiration estimation by means of airborne and satellite remote sensing data

    NASA Astrophysics Data System (ADS)

    Ciraolo, Giuseppe; D'Urso, Guido; Minacapilli, Mario

    2006-09-01

    During the last the two decades, the scientific community developed detailed mathematical models for simulating land surface energy fluxes and crop evapotranspiration rates by means of a energy balance approach. These models can be applied in large areas and with a spatial distributed approach using surface brightness temperature and some ancillary data retrieved from satellite/airborne remote sensed imagery. In this paper a district scale application in combination with multispectral (LandaSat 7 TM data) and hyperspectral airborne MIVIS data has been carried out to test the potentialities of two different energy balance models to estimate evapotranspiration fluxes from a set of typical Mediterranean crops (wine, olive, citrus). The impact of different spatial and radiometric resolutions of MIVIS (3m x 3m) and LandSat (60m x 60m) on models-derived fluxes has been investigated to understand the roles and the main conceptual differences between the two models which respectively use a "single-layer" (SEBAL) and a "two-layer" (TS) schematisation.

  15. Observing tectonic plate motions and deformations from satellite laser ranging

    NASA Technical Reports Server (NTRS)

    Christodoulidis, D. C.; Smith, D. E.; Kolenkiewicz, R.; Klosko, S. M.; Torrence, M. H.

    1985-01-01

    The scope of geodesy has been greatly affected by the advent of artificial near-earth satellites. The present paper provides a description of the results obtained from the reduction of data collected with the aid of satellite laser ranging. It is pointed out that dynamic reduction of satellite laser ranging (SLR) data provides very precise positions in three dimensions for the laser tracking network. The vertical components of the stations, through the tracking geometry provided by the global network and the accurate knowledge of orbital dynamics, are uniquely related to the center of mass of the earth. Attention is given to the observations, the methodologies for reducing satellite observations to estimate station positions, Lageos-observed tectonic plate motions, an improved temporal resolution of SLR plate motions, and the SLR vertical datum.

  16. CEOS Committee on Earth Observations Satellites consolidated report, 1992

    NASA Astrophysics Data System (ADS)

    1992-11-01

    A concise overview of the committee on Earth Observations Satellites (CEOS) and its Working Groups, covering the history and purpose of the Committee and its accomplishments to date are provided. The report will be updated annually before each Plenary meeting, and as developments in the Working Groups warrant. The committee on Earth Observations Satellites (originally named the International Earth Observations Satellite committee, IEOS) was treated in 1984, in response to a recommendation from the Economic Summit of Industrialized Nations Working Group on Growth, Technology, and Employment's Panel of Experts on Satellite Remote Sensing. This group recognized the multidisciplinary nature of satellite Earth observations, and the value of coordinating across all proposed missions. Thus, CEOS combined the previously existing groups for coordination on Ocean Remote-Sensing Satellites (CORSS) and coordination on Land Remote-Sensing Satellites (CLRSS), and established a broad framework for coordination across all spaceborne Earth observations missions. The first three LEOS Plenary meetings focused on treating and guiding the Working Groups deemed necessary to carry out the objectives of the CEOS members. After the third meeting, it was agreed that a more active orientation was required by the Plenary, and additional issues were brought before the group at the fourth meeting. At the fifth Plenary, international scientific programs and relevant intergovernmental organizations accepted invitations and participated as affiliate members of CEOS. This enabled progress toward integrating satellite data users' requirements into the CEOS process. Data exchange principles for global change research were also adopted. An interim CEOS Plenary meeting was held in April 1992, in preparation for the United Nations Conference on Environment and Development (UNCED). Brief encapsulations of the Plenary sessions immediately follow the Terms of Reference that govern the activities of CEOS as

  17. CEOS Committee on Earth Observations Satellites Consolidated Report, 1992

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A concise overview of the committee on Earth Observations Satellites (CEOS) and its Working Groups, covering the history and purpose of the Committee and its accomplishments to date are provided. The report will be updated annually before each Plenary meeting, and as developments in the Working Groups warrant. The committee on Earth Observations Satellites (originally named the International Earth Observations Satellite committee, IEOS) was treated in 1984, in response to a recommendation from the Economic Summit of Industrialized Nations Working Group on Growth, Technology, and Employment's Panel of Experts on Satellite Remote Sensing. This group recognized the multidisciplinary nature of satellite Earth observations, and the value of coordinating across all proposed missions. Thus, CEOS combined the previously existing groups for coordination on Ocean Remote-Sensing Satellites (CORSS) and coordination on Land Remote-Sensing Satellites (CLRSS), and established a broad framework for coordination across all spaceborne Earth observations missions. The first three LEOS Plenary meetings focused on treating and guiding the Working Groups deemed necessary to carry out the objectives of the CEOS members. After the third meeting, it was agreed that a more active orientation was required by the Plenary, and additional issues were brought before the group at the fourth meeting. At the fifth Plenary, international scientific programs and relevant intergovernmental organizations accepted invitations and participated as affiliate members of CEOS. This enabled progress toward integrating satellite data users' requirements into the CEOS process. Data exchange principles for global change research were also adopted. An interim CEOS Plenary meeting was held in April 1992, in preparation for the United Nations Conference on Environment and Development (UNCED). Brief encapsulations of the Plenary sessions immediately follow the Terms of Reference that govern the activities of CEOS as

  18. US EPA: A USER AGENCY PERSPECTIVE ON POLAR SATELLITE OBSERVATIONS

    EPA Science Inventory

    The Agency uses satellite sensor observations in its work on measuring, monitoring and modeling the environment and human health. It generates observations in collaboration with states, local and regional governments, tribes and others, and is a consumer of observations from a v...

  19. Satellite Atmosphere and Io Torus Observations

    NASA Technical Reports Server (NTRS)

    Schneider, Nicholas

    2004-01-01

    NASA's Planetary Astronomy Program has supported a vigorous three-year program of groundbased observations and detailed analysis of the Jupiter/Io system. Our work focused on Io's escaping atmosphere and the plasma torus that it creates.

  20. FORTE satellite observations of VHF radiation from lightning discharges

    SciTech Connect

    Junor, William; Suszcynsky, D. M.; Jacobson, A. R.

    2004-01-01

    The Los Alamos National Laboratory/Sandia National Laboratory FORTE satellite is described and its capabilities for global remote sensing of lightning in the radio regime are described. Some results from 7 years of successful operation are presented. A future global lightning monitoring mission, VGLASS, is described. The FORTE satellite program has provided a powerful tool for the observation and understanding of the natural RF background due to thunderstorm activity. Unfortunately, because of hardware failures, the satellite ceased operation in late summer of 2003 after 6 years of very successful operation.

  1. Small Earth Observing Satellites Flying with Large Satellites in the A-Train

    NASA Technical Reports Server (NTRS)

    Kelly, Angelita C.; Loverro, Adam; Case, Warren F.; Queruel, Nadege; Marechal, Chistophe; Barroso, Therese

    2009-01-01

    This paper/poster presents a real-life example of the benefits of flying small satellites with other satellites, large or small, and vice versa. Typically, most small satellites fly payloads consisting of one or two instruments and fly in orbits that are independent from that of other satellites. The science data from these satellites are either used in isolation or correlated with instrument data from other satellites. Data correlation with other satellites is greatly improved when the measurements of the same point or air mass are taken at approximately the same time. Scientists worldwide are beginning to take advantage of the opportunities for improved data correlation, or coincidental science, offered by the international Earth Observing Constellation known as the A-Train (sometimes referred to as the Afternoon Constellation). Most of the A-Train satellites are small - the A-Train is anchored by two large NASA satellites (EOS-Aqua and EOS-Aura), but consists also of 5 small satellites (CloudSat, CALIPSO, PARASOL, OCO and Glory these last two will join in 2009). By flying in a constellation, each mission benefits from coincidental observations from instruments on the other satellites in the constellation. Essentially, from a data point of view, the A-Train can be envisioned as a single, virtual science platform with multiple instruments. Satellites in the A-Train fly at 705 km in sun-synchronous orbits. Their mean local times at the equator are within seconds to a few minutes of each other. This paper describes the challenges of operating an international constellation of independent satellites from the U.S. and Europe to maximize the coincidental science opportunities while at the same time minimizing the level of operational interactions required between team members. The A-Train mission teams have been able to demonstrate that flying as members of an international constellation does not take away the flexibility to accommodate new requirements. Specific

  2. Use of meteorological satellite observations in weather modification programs

    NASA Technical Reports Server (NTRS)

    Dennis, A. S.; Smith, P. L., Jr.; Biswas, K. R.

    1973-01-01

    The potential value of weather satellite data in field operations of weather modification is appraised. It was found that satellites could play a useful role in operational weather modification projects, particularly in the recognition of treatment opportunities. Satellite cloud photographs and infrared observations appear promising in the identification of treatment opportunities in seeding orographic cloud systems for increased snowpack, in seeding convective clouds for increased rainfall, in identifying hail threats, and in tracking and observing hurricanes as an aid to timing and location of seeding treatments. It was concluded that the potential value of satellite data in the treatment and evaluation phases of operational projects is not as great as in the recognition of treatment opportunity.

  3. Estimation of an Observation Satellite's Attitude Using Multimodal Pushbroom Cameras.

    PubMed

    Perrier, Regis; Arnaud, Elise; Sturm, Peter; Ortner, Mathias

    2015-05-01

    Pushbroom cameras are widely used for earth observation applications. This sensor acquires 1D images over time and uses the straight motion of the satellite to sweep out a region of space and build a 2D image. The stability of the satellite is critical during the pushbroom acquisition process. Therefore its attitude is assumed to be constant overtime. However, the recent manufacture of smaller and lighter satellites to reduce launching cost has weakened this assumption. Small oscillations of the satellite's attitude can result in noticeable warps in images, and geolocation information is lost as the satellite does not capture what it ought to. Current solutions use inertial sensors to control the attitude and correct the images, but they are costly and of limited precision. As the warped images do contain information about attitude variations, we suggest using image registration to estimate them. We exploit the geometry of the focal plane and the stationary nature of the disturbances to recover undistorted images. We embed the estimation in a Bayesian framework where image registration, a prior on attitude variations and a radiometric correction model are fused to retrieve the motion of the satellite. We illustrate the performance of our algorithm on four satellite datasets.

  4. Small satellite's role in future hyperspectral Earth observation missions

    NASA Astrophysics Data System (ADS)

    Guelman, M.; Ortenberg, F.

    2009-06-01

    Along with various advanced satellite onboard sensors, an important place in the near future will belong to hyperspectral instruments, considered as suitable for different scientific, commercial and military missions. As was demonstrated over the last decade, hyperspectral Earth observations can be provided by small satellites at considerably lower costs and shorter timescales, even though with some limitations on resolution, spectral response, and data rate. In this work the requirements on small satellites with imaging hyperspectral sensors are studied. Physical and technological limitations of hyperspectral imagers are considered. A mathematical model of a small satellite with a hyperspectral imaging spectrometer system is developed. The ability of the small satellites of different subclasses (micro- and mini-) to obtain hyperspectral images with a given resolution and quality is examined. As a result of the feasibility analysis, the constraints on the main technical parameters of hyperspectral instruments suitable for application onboard the small satellites are outlined. Comparison of the data for designed and planned instruments with simulation results validates the presented approach to the estimation of the small satellite size limitations. Presented analysis was carried out for sensors with conventional filled aperture optics.

  5. Close Pairings of Galilean Satellites Observed Using Speckle Interferometry

    NASA Astrophysics Data System (ADS)

    Mason, B. D.; Kaplan, G. H.; Douglass, G. G.; Pascu, D.; Aksnes, K.

    1999-09-01

    During November-December 1998, a series of events occurred involving the Galilean satellites of Jupiter, where two satellites (usually Io and Europa, but sometimes Europa and Ganymede) passed within 5 arcsec of each other. Depending on the orbital geometry and closest separation (as close as 2.9 arcsec) the events lasted anywhere from 20 minutes to several hours. Since 5 arcsec roughly defines the atmospheric isoplanatic patch, attempts were made to observe these events using the speckle interferometry camera attached to the U.S. Naval Observatory (USNO) 26-inch refractor. The camera and associated software are normally used for precise measurements of the distance and position angle of binary star components. For the satellite events, the goal was to obtain very precise relative positions of the satellite pairs at specific times, as well as the time of apparent closest separation. Speckle observations of binary stars made from USNO typically yield positional accuracy of about 1 We successfully observed 4 out of a possible 8 events visible from USNO. Reduction of these observations is in progress. Despite the fact that the Galileans are resolved, not point sources, autocorrelations of the speckle patterns appear fairly strong. However, because of the relative motion of the satellites, only short integration times can be used, and it remains to be seen whether the signal-to-noise ratio will permit relative position measurements of useful precision. Close pairings of the Galilean satellites occur in series that are determined by the mutual resonances, within a geometric envelope defined by the apparent inclination of the orbital planes (i.e., Jupiter's equator) and distance. There is another series of events in May-June 1999, then again in January 2000. This technique may also be applicable to some of the Saturnian satellites near the time of ring-plane crossing. We invite other speckle interferometry groups to attempt observations of these events so that the

  6. Satellite-based Observation of the Tectonics of Southern Tibet

    SciTech Connect

    Ryerson, F J; Finkel, R; van der Woerd, J

    2003-02-06

    The Himalayas and the Tibetan Plateau were formed as a result of the collision of India and Asia, and provide an excellent natural laboratory for the investigation of the mechanical response of the outer 100 km of the Earth (the lithosphere) to tectonic stress. Geophysicists are divided in their views on the nature of this response with one group advocating homogeneously distributed deformation in which the lithosphere deforms as a fluid continuum while others contend that deformation is highly localized with the lithosphere deforming as a system of rigid blocks. These rigid blocks or plate undergo little internal deformation. The latter group draws support from the high slip-rates recently observed on strike-slip faults along the northern edge of the Plateau (the Altyn Tagh Fault, ATF), coupled with seismic observations suggesting that these faults penetrate the entire lithosphere. These ''lithospheric faults'' define continental lithospheric plates and facilitate the eastward extrusion of the ''central Tibet plate''. If extrusion of a rigid Tibet occurs then there must be equivalent features at its southern boundary with slip-rates similar to those in the north. The southern boundary of Tibet, defined by the Main Himalayan Thrust (MHT), has no lateral component of motion and is therefore kinematically incompatible with motion in the north. However, a series of features, the Karakorum Fault, the Karakorum-Jiali Fracture Zone (KJFZ), the Jiali Fault and the Red River Fault which lie to the north of the MHT may define the actual, kinematic, southern boundary of this ''central Tibet plate''. We have investigated the rate of slip along the Karakorum Fault (KKF), the major strike-slip fault in southwestern Tibet. If the KKF represents the actual, kinematic, southern boundary of this Tibet, and is the only feature accommodating eastward extrusion of Tibet, then its slip-rate should be similar to that of the ATF in the north. Offsets along the Karakorum Fault ranging

  7. Satellite observations of the Agulhas Current system.

    PubMed

    Quartly, Graham D; Srokosz, Meric A

    2003-01-15

    The Agulhas Current system is a complex interplay of currents and eddies with the bathymetry. Components such as the East Madagascar Retroflection and the Agulhas Return Current evolve significantly over a month, and they are thus not adequately resolved by infrequent research-ship cruises. This paper contrasts the abilities of three different spaceborne sensors for monitoring these complex regimes. A key parameter is sea-surface temperature, measured by both infrared and microwave radiometers. Ocean colour observations of chlorophyll can also be used to distinguish between water masses. PMID:12626239

  8. Observations of Uranus' satellites: Bibliography and literature search

    NASA Technical Reports Server (NTRS)

    Jacobson, R. A.

    1985-01-01

    A literature search has yielded more than 10,000 observations of the satellites of Uranus made from 1787 to 1985. The type (photographic, micrometer) and the number of observations are tabulated in 5 year increments and a complete bibliography is provided.

  9. Satellite Atmosphere and Io Torus Observations

    NASA Technical Reports Server (NTRS)

    Schneider, Nicholas M.

    2000-01-01

    Io is the most volcanically active body in the solar system, and it is embedded deep within the strongest magnetosphere of any planet. This combination of circumstances leads to a host of scientifically compelling phenomena, including (1) an atmosphere out of proportion with such a small object, (2) a correspondingly large atmospheric escape rate, (3) a ring of dense plasma locked in a feedback loop with the atmosphere, and (4) a host of Io-induced emissions from radio bursts to UV auroral spots on Jupiter. This proposal seeks to continue our investigation into the physics connecting these phenomena, with emphasis on Io's atmosphere and plasma torus. The physical processes are clearly of interest for Io, and also other places in the solar system where they are important but not readily observable.

  10. Multi-sensor Observations of the SpinSat Satellite

    NASA Astrophysics Data System (ADS)

    Hall, D.

    The Naval Research Laboratory developed and launched the spherical SpinSat satellite to accomplish two primary goals: 1) study the performance of a new class of micro-thrusters, and 2) provide a calibrated drag experiment to characterize Earth's upper atmosphere during the current period of relatively high solar activity. The 55.9 cm diameter aluminum sphere is equipped with a set of Electrically-Controlled Solid Propellant (ESP) thrusters, oriented to allow both translational and spin-up/spin-down maneuvers. To facilitate remote observations of the satellite's spin rate, the sphere's exterior features a reflectance pattern much like that of a beach-ball, as well as an ensemble of light-emitting diodes (LEDs) arranged along a meridian (i.e., a line of longitude) which can be turned on for brief periods. The Air Force Research Laboratory has conducted optical observations of SpinSat from several ground-based sensors, and more are planned. The observational goals include: 1) obtaining time-resolved, multi-band measurements of the satellite actively firing its micro-thrusters, 2) characterizing the detectability and spatial/temporal morphology of the ESP thruster plumes, 3) measuring the spin rate of the satellite with the LEDs turned on, ideally before and after a spin rate adjustment maneuver, and 4) measuring the spin rate of the satellite in its completely inactive mode, using only passive observations of reflected light and/or thermal emissions.

  11. Planning and Scheduling for Fleets of Earth Observing Satellites

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy; Jonsson, Ari; Morris, Robert; Smith, David E.; Norvig, Peter (Technical Monitor)

    2001-01-01

    We address the problem of scheduling observations for a collection of earth observing satellites. This scheduling task is a difficult optimization problem, potentially involving many satellites, hundreds of requests, constraints on when and how to service each request, and resources such as instruments, recording devices, transmitters, and ground stations. High-fidelity models are required to ensure the validity of schedules; at the same time, the size and complexity of the problem makes it unlikely that systematic optimization search methods will be able to solve them in a reasonable time. This paper presents a constraint-based approach to solving the Earth Observing Satellites (EOS) scheduling problem, and proposes a stochastic heuristic search method for solving it.

  12. Satellite observations of Magnetospheric Line Radiation

    NASA Astrophysics Data System (ADS)

    Nemec, F.; Santolik, O.; Parrot, M.; Berthelier, J. J.

    2006-12-01

    Results of a systematic survey of Magnetospheric Line Radiation (MLR) observed by the DEMETER spacecraft (launched in June, 2004, inclination ~98 degrees, altitude ~700 km, designed to study electromagnetic phenomena connected with seismic or man-made activity) are presented. In order to obtain a statistically significant data set, an automatic identification procedure of possible MLR events has been developed and applied to all the data measured since the beginning of the mission. We show that there are two principally different classes of events: 1) Events with frequency spacing of 50/100 or 60/120 Hz (Power Line Harmonic Radiation, PLHR). The artificial origin of these events from power systems is demonstrated by tracing magnetic field lines to the possible regions of generation. Effects of several parameters (peak intensity, magnetic local time, Kp index, number of lines, frequency) are studied. 2) Events with frequency spacing different from frequencies of power systems ("real-MLR"). Since these emissions usually occur at lower frequencies, it is in many cases possible to use ELF data, where all the 6 components of the electromagnetic field are measured during the Burst mode. We perform a detailed analysis of these events, classifying them into several groups. There is no evidence for their artificial origin.

  13. Students as Ground Observers for Satellite Cloud Retrieval Validation

    NASA Technical Reports Server (NTRS)

    Chambers, Lin H.; Costulis, P. Kay; Young, David F.; Rogerson, Tina M.

    2004-01-01

    The Students' Cloud Observations On-Line (S'COOL) Project was initiated in 1997 to obtain student observations of clouds coinciding with the overpass of the Clouds and the Earth's Radiant Energy System (CERES) instruments on NASA's Earth Observing System satellites. Over the past seven years we have accumulated more than 9,000 cases worldwide where student observations are available within 15 minutes of a CERES observation. This paper reports on comparisons between the student and satellite data as one facet of the validation of the CERES cloud retrievals. Available comparisons include cloud cover, cloud height, cloud layering, and cloud visual opacity. The large volume of comparisons allows some assessment of the impact of surface cover, such as snow and ice, reported by the students. The S'COOL observation database, accessible via the Internet at http://scool.larc.nasa.gov, contains over 32,000 student observations and is growing by over 700 observations each month. Some of these observations may be useful for assessment of other satellite cloud products. In particular, some observing sites have been making hourly observations of clouds during the school day to learn about the diurnal cycle of cloudiness.

  14. NEOWISE: OBSERVATIONS OF THE IRREGULAR SATELLITES OF JUPITER AND SATURN

    SciTech Connect

    Grav, T.; Bauer, J. M.; Mainzer, A. K.; Masiero, J. R.; Sonnett, S.; Kramer, E.; Nugent, C. R.; Cutri, R. M.

    2015-08-10

    We present thermal model fits for 11 Jovian and 3 Saturnian irregular satellites based on measurements from the WISE/NEOWISE data set. Our fits confirm spacecraft-measured diameters for the objects with in situ observations (Himalia and Phoebe) and provide diameters and albedo for 12 previously unmeasured objects, 10 Jovian and 2 Saturnian irregular satellites. The best-fit thermal model beaming parameters are comparable to what is observed for other small bodies in the outer solar system, while the visible, W1, and W2 albedos trace the taxonomic classifications previously established in the literature. Reflectance properties for the irregular satellites measured are similar to the Jovian Trojan and Hilda Populations, implying common origins.

  15. Analysis of Actual Soil Degradation by Erosion Using Satellite Imagery and Terrain Attributes in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Zizala, Daniel

    2015-04-01

    Soil water and wind erosion (possibly tillage erosion) is the most significant soil degradation factor in the Czech Republic. Moreover, this phenomenon also affects seriously quality of water sources., About 50 % of arable land are endangered by water erosion and about 10 % of arable land are endangered wind erosion in the Czech Republic. These processes have been accelerated by human activity. Specific condition of agriculture land in the Czech Republic including highland relief and particularly size of land parcel and intensification of agriculture does not enable to reduce flow of runoff water. Insufficient protection against accelerated erosion processes is related to lack of landscape and hydrographic elements and large area of agricultural plots. Currently, this issue is solved at plot scale by field investigation or at regional scale using numerical and empirical erosion models. Nevertheless, these models enable only to predict the potential of soil erosion. Large scale assessment of actual degradation level of soils is based on expert knowledge. However, there are still many uncertainties in this issue. Therefore characterization of actual degradation level of soil is required especially for assessment of long-term impact of soil erosion on soil fertility. Soil degradation by erosion can be effectively monitored or quantified by modern tools of remote sensing with variable level of detail accessible. Aims of our study is to analyse the applicability of remote sensing for monitoring of actual soil degradation by erosion. Satellite and aerial image data (multispectral and hyperspectral), terrain attributes and data from field investigation are the main source for this analyses. The first step was the delimitation of bare soils using supervised classification of the set of Landsat scenes from 2000 - 2014. The most suitable period of time for obtaining spectral image data with the lowest vegetation cover of soil was determined. The results were verified by

  16. Satellite observations of aerosol and CO over Mexico City

    NASA Astrophysics Data System (ADS)

    Massie, Steven T.; Gille, John C.; Edwards, David P.; Nandi, Sreela

    The development of remote sensing satellite technology potentially will lead to the technical means to monitor air pollution emitted from large cities on a global basis. This paper presents observations by the moderate resolution imaging spectroradiometer (MODIS) and measurements of pollution in the troposphere (MOPITT) experiments of aerosol optical depths and CO mixing ratios, respectively, in the vicinity of Mexico City to illustrate current satellite capabilities. MOPITT CO mixing ratios over Mexico City, averaged between January-March 2002-2005, are 19% above regional values and the CO plume extends over 10° 2 in the free troposphere at 500 hPa. Time series of Red Automatica de Monitoreo Ambiental (RAMA) PM10, and (Aerosol Robotic Network) AERONET and MODIS aerosol optical depths, and RAMA and MOPITT CO time series are inter-compared to illustrate the different perspectives of ground based and satellite instrumentation. Finally, we demonstrate, by examining MODIS and MOPITT data in April 2003, that satellite data can be used to identify episodes in which pollution form fires influences the time series of ground based and satellite observations of urban pollution.

  17. Ground-based and satellite observations of substorm onset features

    NASA Astrophysics Data System (ADS)

    Chang, T.; Cheng, C. Z.; Chiang, C.; Tam, S. W.; Chen, A. B.; Hsu, R.; Su, H.

    2009-12-01

    We present the ground-based and satellite observations of substorm onset events. In the observations from Ground Based Observatories (GBO) and the ISUAL/FORMOSAT-2 satellite, we find structures which consist of periodic bright spots on the auroral arc prior to the substorm expansion phase onset. The intensity of arc grows exponentially before breakup with a linear growth rate of ~O(1-3)sec-1. Under the arc, the negative H-bay associated with the substorm is evident in the ground-based magnetometer data. From ISUAL observations, the first auroral brightening is identified roughly at the beginning of the negative H-bay. The auroral arc is breaks up before dispersionless particle injections are observed at geosynchronous orbit. Based on analysis of these observations, we suggest that this event can be a support of the scenario of substorm onset which is caused by a kinetic ballooning instability which is localized at ~ -10RE.

  18. Gravity waves in the thermosphere observed by the AE satellites

    NASA Technical Reports Server (NTRS)

    Gross, S. H.; Reber, C. A.; Huang, F. T.

    1983-01-01

    Atmospheric Explorer (AE) satellite data were used to investigate the spectra characteristics of wave-like structure observed in the neutral and ionized components of the thermosphere. Power spectral analysis derived by the maximum entropy method indicate the existence of a broad spectrum of scale sizes for the fluctuations ranging from tens to thousands of kilometers.

  19. CORRECTING PHOTOLYSIS RATES ON THE BASIS OF SATELLITE OBSERVED CLOUDS

    EPA Science Inventory

    Clouds can significantly affect photochemical activities in the boundary layer by altering radiation intensity, and therefore their correct specification in the air quality models is of outmost importance. In this study we introduce a technique for using the satellite observed c...

  20. Greenland surface albedo changes 1981-2012 from satellite observations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Significant melt over Greenland has been observed during the last several decades associated with extreme warming events over the northern Atlantic Ocean. An analysis of surface albedo change over Greenland is presented, using a 32-year consistent satellite albedo product from the Global Land Surfac...

  1. Geostationary Atmospheric Observation Satellite Plan in Japan (Invited)

    NASA Astrophysics Data System (ADS)

    Akimoto, H.; Kasai, Y.; Kita, K.; Irie, H.; Sagi, K.; Hayashida, S.

    2009-12-01

    As emissions of air pollutants in Asia have increased in the past decades accompanying with rapid economic growth of developing countries, Asian regional air pollution has attracted concern from the view of inter-continental and intra-continental long-range transport as well as domestic air quality. Particularly in Japan, transboundary transport of ozone is of recent social concern as one of a cause of increasing trend of near surface ozone concentration. In order to elucidate the transport and chemical transformation processes of air pollution in East Asia, and to attain internationally common understanding on this issue, geostationary atmospheric observation satellite has been proposed in Japan. In 2006, the Japan Society of Atmospheric Chemistry (JSAC) formed Commission on the Atmospheric Environmental Observation Satellite to initiate the discussion. In 2009, Committee on Geostationary Atmospheric Observation Satellite has been formed within JAXA to promote the plan. The proposed satellite consists of a UV/VIS sensor for O3, NO2, HCHO and AOT, and a MIR sensor for O3, CO, HNO3, NO2, H2O and temperature. Targeted spatial and temporal resolutions are ca.10 km and 1-2 hrs, respectively, and focused observation area is northeast Asia potentially covering the southeast and south Asia. Sensitivity analysis and simulation have been made for both the UV/VIS and MIR sensors. Overview of user requirement and the sensitivity analysis for each species will be presented in this talk.

  2. Sensor Web Interoperability Testbed Results Incorporating Earth Observation Satellites

    NASA Technical Reports Server (NTRS)

    Frye, Stuart; Mandl, Daniel J.; Alameh, Nadine; Bambacus, Myra; Cappelaere, Pat; Falke, Stefan; Derezinski, Linda; Zhao, Piesheng

    2007-01-01

    This paper describes an Earth Observation Sensor Web scenario based on the Open Geospatial Consortium s Sensor Web Enablement and Web Services interoperability standards. The scenario demonstrates the application of standards in describing, discovering, accessing and tasking satellites and groundbased sensor installations in a sequence of analysis activities that deliver information required by decision makers in response to national, regional or local emergencies.

  3. Globally Gridded Satellite (GridSat) Observations for Climate Studies

    NASA Technical Reports Server (NTRS)

    Knapp, Kenneth R.; Ansari, Steve; Bain, Caroline L.; Bourassa, Mark A.; Dickinson, Michael J.; Funk, Chris; Helms, Chip N.; Hennon, Christopher C.; Holmes, Christopher D.; Huffman, George J.; Kossin, James P.; Lee, Hai-Tien; Loew, Alexander; Magnusdottir, Gudrun

    2012-01-01

    Geostationary satellites have provided routine, high temporal resolution Earth observations since the 1970s. Despite the long period of record, use of these data in climate studies has been limited for numerous reasons, among them: there is no central archive of geostationary data for all international satellites, full temporal and spatial resolution data are voluminous, and diverse calibration and navigation formats encumber the uniform processing needed for multi-satellite climate studies. The International Satellite Cloud Climatology Project set the stage for overcoming these issues by archiving a subset of the full resolution geostationary data at approx.10 km resolution at 3 hourly intervals since 1983. Recent efforts at NOAA s National Climatic Data Center to provide convenient access to these data include remapping the data to a standard map projection, recalibrating the data to optimize temporal homogeneity, extending the record of observations back to 1980, and reformatting the data for broad public distribution. The Gridded Satellite (GridSat) dataset includes observations from the visible, infrared window, and infrared water vapor channels. Data are stored in the netCDF format using standards that permit a wide variety of tools and libraries to quickly and easily process the data. A novel data layering approach, together with appropriate satellite and file metadata, allows users to access GridSat data at varying levels of complexity based on their needs. The result is a climate data record already in use by the meteorological community. Examples include reanalysis of tropical cyclones, studies of global precipitation, and detection and tracking of the intertropical convergence zone.

  4. Permanent GNSS Observations at Agh-Ust Satellite Observatory

    NASA Astrophysics Data System (ADS)

    Kudrys, Jacek

    2016-06-01

    GPS satellite observations at the Faculty of Mining Surveying and Environmental Engineering AGH-UST are conducted since the early 90s of the last century. In 2001, efforts have been made on getting permanently functioning GPS station. At present, observatory is EPN operational center for two GNSS stations KRAW and KRA1. Moreover, KRA1 station is one of fundamental control points in polish horizontal network. The article gives the history and scope of the research carried out in the satellite observatory AGH-UST during the period 2001 - 2015.

  5. SLR system improvement for GIOVE-A satellite observation

    NASA Astrophysics Data System (ADS)

    Zhao, You; Fan, Cunbo; Han, Xingwei; Yang, Dingjiang; Chen, Nianjiang; Xue, Feng; Geng, Lin

    2008-03-01

    Galileo system consists of 27 satellites distributed in three uniformly separated planes. At the end of 2005, one satellite, Galileo In-Orbit Validation Element-A (GIOVE-A), was launched as planned into an MEO with an altitude of 23,260 kilometers. Carrying a payload of rubidium clocks, signal-generation units, and a phase-array antenna of individual L-band elements. GIOVE-A started broadcasting on January 28, 2006, securing the frequencies allocated by the ITU for Galileo. Performance of the on-board atomic clocks, antenna infrastructure, and signal properties is evaluated through precise orbit determination, supported by Satellite Laser Ranging (SLR), an independent high-precision range measurement technique for orbit determination based on a global network of stations that measure the round-trip flight-time of ultra short laser pulses to satellites equipped with laser retro reflector arrays (LRAs). SLR provides instantaneous range measurements of millimeter-level precision which can be compiled to provide accurate orbits and to measure the on-board clock error. Given the importance of SLR data for the characterization of the GIOVE-A clocks, the Changchun SLR station in northeast China was selected among the Chinese stations contributing to the ILRS because it had demonstrated strong MEO satellite tracking; collocation with an existing International GPS Service station; and good weather conditions. This paper introduces the SLR system improvement for tracking GIOVE-A satellite in Changchun station. During the more than two months improvement, the new servo and encoder systems were installed, primary mirror, second mirror and some other mirrors have been cleaned and recoated, and the laser system was adjusted in order to improve the laser efficiency and output energy. The paper gives out the improvement results, and the GIOVE-A satellite observation results.

  6. Sensor system for Greenhouse Gas Observing Satellite (GOSAT)

    NASA Astrophysics Data System (ADS)

    Hamazaki, Takashi; Kuze, Akihiko; Kondo, Kayoko

    2004-11-01

    Global warming has become a very serious issue for human beings. In 1997, the Kyoto Protocol was adopted at the Third Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP3), making it mandatory for developed nations to reduce carbon dioxide emissions by six (6) to eight (8) per cent of their total emissions in 1990, and to meet this goal sometime between 2008 and 2012. The Greenhouse gases Observing SATellite (GOSAT) is design to monitor the global distribution of carbon dioxide (CO2) from orbit. GOSAT is a joint project of Japan Aerospace Exploration Agency (JAXA), the Ministry of Environment (MOE), and the National Institute for Environmental Studies (NIES). JAXA is responsible for the satellite and instrument development, MOE is involved in the instrument development, and NIES is responsible for the satellite data retrieval. The satellite is scheduled to be launched in 2008. In order to detect the CO2 variation of boundary layers, both the technique to measure the column density and the retrieval algorithm to remove cloud and aerosol contamination are investigated. Main mission sensor of the GOSAT is a Fourier Transform Spectrometer with high optical throughput, spectral resolution and wide spectral coverage, and a cloud-aerosol detecting imager attached to the satellite. The paper presents the mission sensor system of the GOSAT together with the results of performance demonstration with proto-type instrument aboard an aircraft.

  7. Fourier transform spectrometer for Greenhouse Gases Observing Satellite (GOSAT)

    NASA Astrophysics Data System (ADS)

    Hamazaki, Takashi; Kaneko, Yutaka; Kuze, Akihiko; Kondo, Kayoko

    2005-01-01

    Global warming has become a very serious issue for human beings. In 1997, the Kyoto Protocol was adopted at the Third Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP3), making it mandatory for developed nations to reduce carbon dioxide emissions by six (6) to eight (8) per cent of their total emissions in 1990, and to meet this goal sometime between 2008 and 2012. The Greenhouse gases Observing SATellite (GOSAT) is designed to monitor the global distribution of carbon dioxide (CO2) from the space. GOSAT is a joint project of Japan Aerospace Exploration Agency (JAXA), the Ministry of Environment (MOE), and the National Institute for Environmental Studies (NIES). JAXA is responsible for the satellite and instrument development, MOE is involved in the instrument development, and NIES is responsible for the satellite data retrieval. The satellite is scheduled to be launched in 2008. In order to detect the CO2 variation of boundary layers, both the technique to measure the column density and the retrieval algorithm to remove cloud and aerosol contamination are investigated. Main mission sensor of the GOSAT is a Fourier Transform Spectrometer with high optical throughput, spectral resolution and wide spectral coverage, and a cloud-aerosol detecting imager attached to the satellite. The paper presents the mission sensor system of the GOSAT together with the results of performance demonstration with proto-type instrument aboard an aircraft.

  8. Use of Earth Observing Satellites for Operational Hazard Support

    NASA Astrophysics Data System (ADS)

    Wood, H. M.; Lauritson, L.

    The National Oceanic and Atmospheric Administration (NOAA) relies on Earth observing satellite data to carry out its operational mission to monitor, predict, and assess changes in the Earth's atmosphere, land, and oceans. NOAA's National Environmental Satellite, Data, and Information Service (NESDIS) uses satellite data to help lessen the impacts of natural and man-made disasters due to tropical cyclones, flash floods, heavy snowstorms, volcanic ash clouds (for aviation safety), sea ice (for shipping safety), and harmful algal blooms. Communications systems on NOAA satellites are used to support search and rescue and to relay data from data collection platforms to a variety of users. NOAA's Geostationary (GOES) and Polar (POES) Operational Environmental Satellites are used in conjunction with other satellites to support NOAA's operational mission. While NOAA's National Hurricane Center is responsible for predicting tropical cyclones affecting the U.S. mainland, NESDIS continuously monitors the tropics world wide, relaying valuable satellite interpretations of tropical systems strength and position to users throughout the world. Text messages are sent every six hours for tropical cyclones in the Western Pacific, South Pacific, and Indian Oceans. To support the monitoring, prediction, and assessment of flash floods and winter storms, NESDIS sends out text messages alerting U.S. weather forecast offices whenever NOAA satellite imagery indicates the occurrence of heavy rain or snow. NESDIS also produces a 24-hour rainfall composite graphic image covering those areas affected by heavy precipitation. The International Civil Aviation Organization (ICAO) and other aviation concerns recognized the need to keep aviators informed of volcanic hazards. To that end, nine Volcanic Ash Advisory Centers (VAAC's) were created to monitor volcanic ash plumes within their assigned airspace. NESDIS hosts one of the VAAC's. Although the NESDIS VAAC's primary responsibility is the

  9. Satellite Observation Systems for Polar Climate Change Studies

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.

    2012-01-01

    The key observational tools for detecting large scale changes of various parameters in the polar regions have been satellite sensors. The sensors include passive and active satellite systems in the visible, infrared and microwave frequencies. The monitoring started with Tiros and Nimbus research satellites series in the 1970s but during the period, not much data was stored digitally because of limitations and cost of the needed storage systems. Continuous global data came about starting with the launch of ocean color, passive microwave, and thermal infrared sensors on board Nimbus-7 and Synthetic Aperture Radar, Radar Altimeter and Scatterometer on board SeaSat satellite both launched in 1978. The Nimbus-7 lasted longer than expected and provided about 9 years of useful data while SeaSat quit working after 3 months but provided very useful data that became the baseline for follow-up systems with similar capabilities. Over the years, many new sensors were launched, some from Japan Aeronautics and Space Agency (JAXA), some from the European Space Agency (ESA) and more recently, from RuSSia, China, Korea, Canada and India. For polar studies, among the most useful sensors has been the passive microwave sensor which provides day/night and almost all weather observation of the surface. The sensor provide sea surface temperature, precipitation, wind, water vapor and sea ice concentration data that have been very useful in monitoring the climate of the region. More than 30 years of such data are now available, starting with the Scanning Multichannel Microwave Radiometer (SMMR) on board the Nimbus-7, the Special Scanning Microwave/Imager (SSM/I) on board a Defense Meteorological Satellite Program (DMSP) and the Advanced Microwave Scanning Radiometer on board the EOS/ Aqua satellite. The techniques that have been developed to derive geophysical parameters from data provided by these and other sensors and associated instrumental and algorithm errors and validation techniques

  10. Whistler-triggered emissions observed by ISIS satellites

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Ondoh, T.

    1989-01-01

    A statistical examination has been conducted of the ducted and nonducted whistler-triggered emissions (WTEs) observed by the ISIS satellites in the 1979-1981 period. Most WTEs are observed with simultaneous lower hybrid resonance in the topside ionosphere. The VLF emissions triggered by ducted whistlers frequently occur at L of 2-3, while those triggered by nonducted whistlers occur in the wider latitudinal regions at L of 2.2-4.3.

  11. Influence of ground scattering on satellite auroral observations.

    PubMed

    Hays, P B; Anger, C D

    1978-06-15

    Satellite observations of the optical emission features in the aurora and nighttime airglow are usually contaminated by scattering from clouds and snow. It is shown here that this contamination can easily be removed when the emission layer is viewed against a surface of known albedo. The effect of the earth's curvature, parallax, and varying image angle are found to be significant but can be removed from the observation.

  12. Influence of ground scattering on satellite auroral observations

    NASA Technical Reports Server (NTRS)

    Hays, P. B.; Anger, C. D.

    1978-01-01

    Satellite observations of the optical emission features in the aurora and nighttime airglow are usually contaminated by scattering from clouds and snow. It is shown here that this contamination can easily be removed when the emission layer is viewed against a surface of known albedo. The effect of the earth's curvature, parallax, and varying image angle are found to be significant but can be removed from the observation.

  13. Remote Observing with the Keck Telescope Using the ACTS Satellite

    NASA Technical Reports Server (NTRS)

    Cohen, Judy; Shopbell, Patrick; Bergman, Larry

    1998-01-01

    As a technical demonstration project for the NASA Advanced Communications Technology Satellite (ACTS), we have implemented remote observing on the 10-meter Keck II telescope on Mauna Kea in Hawaii from the California Institute of Technology campus in Pasadena. The data connection consists of optical fiber networks in Hawaii and California, connecting the end-points to high data rate (HDR) ACTS satellite antennae at JPL in Pasadena and at the Tripler Army Medical Center in Honolulu. The terrestrial fiber networks run the asynchronous transfer mode (ATM) protocol at DS-3 (45 Mbit/sec) speeds, providing ample bandwidth to enable remote observing with a software environment identical to that used for on-site observing in Hawaii. This experiment has explored the data requirements of remote observing with a modern research telescope and large-format detector arrays. While the maximum burst data rates are lower than those required for many other applications (e.g., HDTV), the network reliability and data integrity requirements are critical. As we show in this report, the former issue particularly may be the greatest challenge for satellite networks for this class of application. We have also experimented with the portability of standard TCP/IP applications to satellite networks, demonstrating the need for alternative TCP congestion algorithms and minimization of bit error rates (BER). Reliability issues aside, we have demonstrated that true remote observing over high-speed networks provides several important advantages over standard observing paradigms. Technical advantages of the high-speed network access include more rapid download of data to a user's home institution and the opportunity for alternative communication facilities between members of an observing team, such as audio- and videoconferencing.

  14. Principle characteristics of the National Earth Observation Satellite. Project SPOT

    NASA Technical Reports Server (NTRS)

    Cazenave, M.

    1977-01-01

    A recent meeting of the Economic and Social Committee examined the programs and means currently being implemented by France in the field in the field of space research and industry which could bring about fast results. This was prompted by man's desire to insure rational resource management of his planet and by man's awareness of the definite contribution that space observation can make to this field of research. Through discussion, the Economic and Social Committee has approved the plan for creating an earth observation satellite. A detailed discussion of the principle characteristics of this earth observation satellite include the objectives, the orbit, characteristics and operations of the platform, maintenance, attitude measurement, the power available and many other characteristics.

  15. Observations of artificially produced scintillations using satellite transmissions

    NASA Technical Reports Server (NTRS)

    Pope, J. H.; Fritz, R. B.

    1974-01-01

    The ionospheric modification experiment, utilizing a high-powered transmitter, provides an opportunity to study ionospheric irregularities under relatively known conditions. The irregularities were studied by means of transionospheric signals from the polar-orbiting satellite ESSA 8 transmitting at 137 MHz. These observations show that scintillations occur when the satellite to ground station geometry is such that the ray from the satellite passes through the region in the ionosphere under modification. In general, a cut across the illuminated volume is obtained; thus an active region of about 100 km in diameter is indicated. For the most part, the artificial scintillations appear to be similar to those obtained from naturally occurring irregularities, but a systematic change from 3 to 1 sec in the fluctuation period is usually observed as the satellite traverses from the northern to the southern portions of the active region. The change in period appears to be produced by a systematic change in irregularity scale size from about 4 to about 1 km.

  16. Possible satellite-based observations of the 1997 Leonid meteoroids

    SciTech Connect

    Pongratz, M.B.; Carlos, R.C.; Cayton, T.

    1998-12-01

    The Block IIA GPS satellites are equipped with a sensor designed to detect electromagnetic transients. Several phenomena will produce triggers in this sensor. They include earth-based electromagnetic transients such as lightning and two space-based phenomena--deep dielectric discharge and meteoroid or hyper-velocity micro-gram particle impact (HMPI). Energetic electrons in the GPS environment cause the deep dielectric charging. HMPIs cause triggers through the transient electric fields generated by the ejecta plasma. During the 1997 Leonid passage the energetic particle fluxes were very low. In the presence of such low fluxes the typical median trigger rate is 20 per minute with a standard deviation of about 20 per minute. Between 0800 UT and 1200 UT on November 17, 1997, the sensor on a specially configured satellite observed trigger rates more than 10 sigma above the nominal median rate. Sensors on other Block IIA GPS satellites also observed excess triggers during November. Detection is enhanced when the sensor antenna is oriented into the Leonid radiant. While many questions persist the authors feel that it is likely that the excess events during the November interval were caused by the close approach of the satellites to the Leonid meteoroid path.

  17. A comparison of some observations of the Galilean satellites with Sampson's tables. [position error analysis

    NASA Technical Reports Server (NTRS)

    Arlot, J.-E.

    1975-01-01

    Two series of photographic observations of the Galilean satellites are analyzed to determine systematic errors in the observations and errors in Sampson's (1921) theory. Satellite-satellite as well as planet-satellite positions are used in comparing theory with observation. Ten unknown errors are identified, and results are presented for three determinations of the unknown longitude error.

  18. Observing outer planet satellites (except Titan) with JWST: Science justification and observational requirements

    USGS Publications Warehouse

    Kestay, Laszlo P.; Grundy, Will; Stansberry, John; Sivaramakrishnan, Anand; Thatte, Deepashri; Gudipati, Murthy; Tsang, Constantine; Greenbaum, Alexandra; McGruder, Chima

    2016-01-01

    The James Webb Space Telescope (JWST) will allow observations with a unique combination of spectral, spatial, and temporal resolution for the study of outer planet satellites within our Solar System. We highlight the infrared spectroscopy of icy moons and temporal changes on geologically active satellites as two particularly valuable avenues of scientific inquiry. While some care must be taken to avoid saturation issues, JWST has observation modes that should provide excellent infrared data for such studies.

  19. Assimilating Satellite SST Observations into a Diurnal Cycle Model

    NASA Astrophysics Data System (ADS)

    Pimentel, S.; Haines, K.; Nichols, N. K.

    2006-12-01

    The wealth of satellite sea surface temperature (SST) data now available opens the possibility of large improvements in SST estimation. However the use of such data is not straight forward; a major difficulty in assimilating satellite observations is that they represent a near surface temperature, whereas in ocean models the top level represents the temperature at a greater depth. During the day, under favourable conditions of clear skies and calm winds, the near surface temperature is often seen to have a diurnal cycle that is picked up in satellite observations. Current ocean models do not have the vertical or temporal resolution to adequately represent this daytime warming. The usual approach is to discard daytime observations as they are considered diurnally `corrupted'. A new assimilation technique is developed here that assimilates observations into a diurnal cycle model. The diurnal cycle of SSTs are modelled using a 1-D mixed layer model with fine near surface resolution and 6 hourly forcing from NWP analyses. The accuracy of the SST estimates are hampered by uncertainties in the forcing data. The extent of diurnal SST warming at a particular location and time is predominately governed by a non-linear response to cloud cover and sea surface wind speeds which greatly affect the air-sea fluxes. The method proposed here combines infrared and microwave SST satellite observations in order to derive corrections to the cloud cover and wind speed values over the day. By adjusting the forcing, SST estimation and air-sea fluxes should be improved and are at least more consistent with each other. This new technique for assimilating SST data can be considered a tool for producing more accurate diurnal warming estimates.

  20. Observation of global electromagnetic resonances by low- orbiting satellites

    NASA Astrophysics Data System (ADS)

    Surkov, V. V.

    2016-02-01

    Penetration of Schumann resonances energy from the Earth-ionosphere resonance cavity into the circumterrestrial space is examined. This study focuses on estimates of Alfvén wave amplitude and spectra in the frequency range of 7-50 Hz which can be observed by low-orbiting satellites. Differences in Schumann resonances observation conditions between the nighttime and sunlit sides of the ionosphere are analyzed. Particular emphasis has been placed on the ionospheric Alfvén resonator (IAR) excited by both global thunderstorm activity and individual lightning discharges. IAR spectra in the frequency range of 0.5-10 Hz are calculated for ionospheric altitudes. The calculated spectral amplitudes of IAR and Schumann resonances are compatible with C/NOFS satellite observations. To explain a shift of IAR resonant frequencies observed during C/NOFS satellite passage through terminator region, the IAR model is developed in which an interference of Alfvén waves reflected from the ionospheric E-layer and the IAR upper boundary is taken into account.

  1. The alignment between satellites and central galaxies: theory versus observations

    NASA Astrophysics Data System (ADS)

    Kang, X.; van den Bosch, Frank C.; Yang, Xiaohu; Mao, Shude; Mo, H. J.; Li, Cheng; Jing, Y. P.

    2007-07-01

    Recent studies have shown that the distribution of satellite galaxies is preferentially aligned with the major axis of their central galaxy. The strength of this alignment has been found to depend strongly on the colours of the satellite and central galaxies, and only weakly on the mass of the halo in which the galaxies reside. In this paper we study whether these alignment signals, and their dependence on galaxy and halo properties, can be reproduced in a hierarchical structure formation model of a ΛCDM concordance cosmology. To that extent we use a large N-body simulation which we populate with galaxies following a semi-analytical model for galaxy formation. We find that if the orientation of the central galaxy is perfectly aligned with that of its dark matter halo, then the predicted central-satellite alignment signal is much stronger than observed. If, however, the minor axis of a central galaxy is perfectly aligned with the angular momentum vector of its dark matter halo, we can accurately reproduce the observed alignment strength as a function of halo mass and galaxy colour. Although this suggests that the orientation of central galaxies is governed by the angular momentum of their dark matter haloes, we emphasize that any other scenario in which the minor axes of central galaxy and halo are misaligned by ~40° (on average) will match the data equally well. Finally, we show that dependence of the alignment strength on the colour of the central galaxy is most likely an artefact due to interlopers in the group catalogue. The dependence on the colour of the satellite galaxies, on the other hand, is real and owes to the fact that red satellites are associated with subhaloes that were more massive at their time of accretion.

  2. Astrometric observations and comparison with theory of Saturn's satellites from Bordeaux Observatory, 1984

    NASA Astrophysics Data System (ADS)

    Dourneau, G.; Le Campion, J. F.; Dulou, M. R.

    1989-08-01

    The astrometric observations of Saturn's satellites reported in this paper have been reduced from the SAO catalog. Observed positions of the satellites are given both in absolute topocentric astrometric coordinates and in differential coordinates by using a reference satellite. Residuals derived from comparison between observed and computed positions of the satellites are also reported. A discussion shows that Iapetus, which presents the highest residuals, needs, more than all other observed satellites, an improvement of its theory of motion.

  3. Satellite microwave observations of a storm complex: A comparative analysis

    NASA Technical Reports Server (NTRS)

    Martin, D. W.

    1985-01-01

    The hypothesis that cold events correspond to a particular stage in a class of thunderstorms was tested. That class is a storms class which updrafts are: (1) strong, broad and moist, and (2) extend well above the freezing level. Condition (1) implies strong mesoscale forcing. Condition (2) implies a tall updraft or a relatively low freezing level. Such storms should have big, intense radar echoes and cold, fast-growing anvils. The thunderstorm events were analyzed by radar, rain gauge and GOES infrared observations. Radar was the starting point for detection and definition of the hypothesized thunderstorms. The radar signature is compared to the signature of the storm in rain gauge observations, satellite infrared images and satellite microwave images.

  4. Large Scale Surface Radiation Budget from Satellite Observation

    NASA Technical Reports Server (NTRS)

    Pinker, R. T.

    1995-01-01

    During the current reporting period, the focus of our work was on preparing and testing an improved version of our Surface Radiation Budget algorithm for processing the ISCCP D1 data routinely at the SRB Satellite Data Analysis Center (SDAC) at NASA Langley Research Center. The major issues addressed are related to gap filling and to testing whether observations made from ERBE could be used to improve current procedures of converting narrowband observations, as available from ISCCP, into broadband observations at the TOA. The criteria for selecting the optimal version are to be based on results of intercomparison with ground truth.

  5. Is Ecosystem-Atmosphere Observation in Long-Term Networks actually Science?

    NASA Astrophysics Data System (ADS)

    Schmid, H. P. E.

    2015-12-01

    Science uses observations to build knowledge by testable explanations and predictions. The "scientific method" requires controlled systematic observation to examine questions, hypotheses and predictions. Thus, enquiry along the scientific method responds to questions of the type "what if …?" In contrast, long-term observation programs follow a different strategy: we commonly take great care to minimize our influence on the environment of our measurements, with the aim to maximize their external validity. We observe what we think are key variables for ecosystem-atmosphere exchange and ask questions such as "what happens next?" or "how did this happen?" This apparent deviation from the scientific method begs the question whether any explanations we come up with for the phenomena we observe are actually contributing to testable knowledge, or whether their value remains purely anecdotal. Here, we present examples to argue that, under certain conditions, data from long-term observations and observation networks can have equivalent or even higher scientific validity than controlled experiments. Internal validity is particularly enhanced if observations are combined with modeling. Long-term observations of ecosystem-atmosphere fluxes identify trends and temporal scales of variability. Observation networks reveal spatial patterns and variations, and long-term observation networks combine both aspects. A necessary condition for such observations to gain validity beyond the anecdotal is the requirement that the data are comparable: a comparison of two measured values, separated in time or space, must inform us objectively whether (e.g.) one value is larger than the other. In turn, a necessary condition for the comparability of data is the compatibility of the sensors and procedures used to generate them. Compatibility ensures that we compare "apples to apples": that measurements conducted in identical conditions give the same values (within suitable uncertainty intervals

  6. Satellite observations and instrumentation for imaging energetic neutral atoms

    NASA Astrophysics Data System (ADS)

    Voss, Henry D.; Mobilia, Joseph; Collin, Henry L.; Imhof, William L.

    1992-06-01

    Direct measurements of energetic neutral atoms (ENA) and ions have been obtained with the cooled solid state detectors on the low altitude (220 km) three-axis stabilized S81-1/SEEP satellite and on the spinning 400 km X 5.5 Re CRRES satellite. During magnetic storms ENA and ion precipitation (E > 10 keV) is evident over the equatorial region from the LE spectrometer on the SEEP payload (ONR 804). The spinning motion of the CRRES satellite allows for simple mapping of the magnetosphere using the IMS-HI (ONR 307-8-3) neutral spectrometer. This instrument covers the energy range from 20 to 1000 keV and uses a 7 kG magnetic field to screen out protons less than about 50 MeV. ENA and the resulting low- altitude ion belt have been observed with the IMS-HI instrument. Recently, an advanced spectrometer (SEPS) has been developed to image electrons, ions, and neutrals on the despun platform of the POLAR satellite (approximately 1.8 X 9 Re) for launch in the mid-90's as part of the NASA ISTP/GGS program. For this instrument a 256 element solid state pixel array has been developed that interfaces to 256 amplifier strings using a custom 16 channel microcircuit chip. In addition, this instrument features a motor controlled iris wheel and anticoincidence electronics.

  7. Observations of the mutual phenomena of Saturnian satellites in 1980

    NASA Astrophysics Data System (ADS)

    Soma, M.; Nakamura, T.

    1982-06-01

    Sinclair's (1977) theory is used in a preliminary orbital analysis of five mutual phenomena of the Saturnian satellites in 1980. Midtimes and light losses (normalized to unity) of the events determined from the observed light curves are given, together with calculations made with the orbital elements obtained. In order to check the present computer calculations, results have been compared with the predictions of Aksnes and Franklin (1978), in which substantially the same orbital elements are used.

  8. Ongoing &new project in observation and sciences using micro satellite

    NASA Astrophysics Data System (ADS)

    Deligny, B.

    2004-11-01

    : This paper present the evolution studded and under development on the MYRIADE product line, where Alcatel and CNES has a partnership. These evolutions are proposed to fulfil the need of new missions on several domains such as science and earth observation in several orbits, increasing the energy for the payload, new orbit control strategy. These missions are succinctly described, the impacts on the satellite definition are mentioned and the solutions adopted are described.

  9. Analysis of UV Satellite and Ground Observed data for Sardinia

    NASA Astrophysics Data System (ADS)

    Cervone, Guido; Manca, Germana; Johnson, Kathleen

    Ultraviolet (UV) radiation in the 280 to 400 nanometers range has been found to be one of the primary cause for skin cancer. The correlation between UV radiation and skin cancer prevention is of global concern. Satellite observations from Nimbus7 (1978-1993), EarthProbe (1996-2004) and OMI/AURA (2004-present) provide long term UV time-series that can be used to study and compute the risk associated with exposure to harmful radiation. Additionally, several ground installations exist to acquire UV radiation data that can be paired with satellite observations. The current work presents the data mining analysis of UV time series from 1978 to present for the Italian region of Sardinia. Satellite observations are paired with ground measurements to provide historical averages of UV radiation, and daily maps of current exposure. A Geographical Information System (GIS) is used to fuse UV data with ground characteristics. The use of GIS is fundamental to calculate the real value of UV on the ground. It is known that the incidence of solar radiation, and consequently of UV, is modified by topography and surface features. Topography plays a important rule, because it is a major factor that determines the spatial variability of insulation and UV being a part of direct insulation. variation in elevation orientation (slope and aspect), and shadow cast by topographical features, determine the UV insulation in a given area or point.

  10. Chemistry-Transport Modeling of the Satellite Observed Distribution of Tropical Tropospheric Ozone

    NASA Technical Reports Server (NTRS)

    Peters, Wouter; Krol, Maarten; Dentener, Frank; Thompson, Anne M.; Leloeveld, Jos; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    We have compared the 14-year record of satellite derived tropical tropospheric ozone columns (TTOC) from the NIMBUS-7 Total Ozone Mapping Spectrometer (TOMS) to TTOC calculated by a chemistry-transport model (CTM). An objective measure of error, based on the zonal distribution of TTOC in the tropics, is applied to perform this comparison systematically. In addition, the sensitivity of the model to several key processes in the tropics is quantified to select directions for future improvements. The comparisons indicate a widespread, systematic (20%) discrepancy over the tropical Atlantic Ocean, which maximizes during austral Spring. Although independent evidence from ozonesondes shows that some of the disagreement is due to satellite over-estimate of TTOC, the Atlantic mismatch is largely due to a misrepresentation of seasonally recurring processes in the model. Only minor differences between the model and observations over the Pacific occur, mostly due to interannual variability not captured by the model. Although chemical processes determine the TTOC extent, dynamical processes dominate the TTOC distribution, as the use of actual meteorology pertaining to the year of observations always leads to a better agreement with TTOC observations than using a random year or a climatology. The modeled TTOC is remarkably insensitive to many model parameters due to efficient feedbacks in the ozone budget. Nevertheless, the simulations would profit from an improved biomass burning calendar, as well as from an increase in NOX abundances in free tropospheric biomass burning plumes. The model showed the largest response to lightning NOX emissions, but systematic improvements could not be found. The use of multi-year satellite derived tropospheric data to systematically test and improve a CTM is a promising new addition to existing methods of model validation, and is a first step to integrating tropospheric satellite observations into global ozone modeling studies. Conversely

  11. Observing system simulations for small satellite formations estimating bidirectional reflectance

    NASA Astrophysics Data System (ADS)

    Nag, Sreeja; Gatebe, Charles K.; Weck, Olivier de

    2015-12-01

    The bidirectional reflectance distribution function (BRDF) gives the reflectance of a target as a function of illumination geometry and viewing geometry, hence carries information about the anisotropy of the surface. BRDF is needed in remote sensing for the correction of view and illumination angle effects (for example in image standardization and mosaicing), for deriving albedo, for land cover classification, for cloud detection, for atmospheric correction, and other applications. However, current spaceborne instruments provide sparse angular sampling of BRDF and airborne instruments are limited in the spatial and temporal coverage. To fill the gaps in angular coverage within spatial, spectral and temporal requirements, we propose a new measurement technique: use of small satellites in formation flight, each satellite with a VNIR (visible and near infrared) imaging spectrometer, to make multi-spectral, near-simultaneous measurements of every ground spot in the swath at multiple angles. This paper describes an observing system simulation experiment (OSSE) to evaluate the proposed concept and select the optimal formation architecture that minimizes BRDF uncertainties. The variables of the OSSE are identified; number of satellites, measurement spread in the view zenith and relative azimuth with respect to solar plane, solar zenith angle, BRDF models and wavelength of reflection. Analyzing the sensitivity of BRDF estimation errors to the variables allow simplification of the OSSE, to enable its use to rapidly evaluate formation architectures. A 6-satellite formation is shown to produce lower BRDF estimation errors, purely in terms of angular sampling as evaluated by the OSSE, than a single spacecraft with 9 forward-aft sensors. We demonstrate the ability to use OSSEs to design small satellite formations as complements to flagship mission data. The formations can fill angular sampling gaps and enable better BRDF products than currently possible.

  12. Observing System Simulations for Small Satellite Formations Estimating Bidirectional Reflectance

    NASA Technical Reports Server (NTRS)

    Nag, Sreeja; Gatebe, Charles K.; de Weck, Olivier

    2015-01-01

    The bidirectional reflectance distribution function (BRDF) gives the reflectance of a target as a function of illumination geometry and viewing geometry, hence carries information about the anisotropy of the surface. BRDF is needed in remote sensing for the correction of view and illumination angle effects (for example in image standardization and mosaicing), for deriving albedo, for land cover classification, for cloud detection, for atmospheric correction, and other applications. However, current spaceborne instruments provide sparse angular sampling of BRDF and airborne instruments are limited in the spatial and temporal coverage. To fill the gaps in angular coverage within spatial, spectral and temporal requirements, we propose a new measurement technique: Use of small satellites in formation flight, each satellite with a VNIR (visible and near infrared) imaging spectrometer, to make multi-spectral, near-simultaneous measurements of every ground spot in the swath at multiple angles. This paper describes an observing system simulation experiment (OSSE) to evaluate the proposed concept and select the optimal formation architecture that minimizes BRDF uncertainties. The variables of the OSSE are identified; number of satellites, measurement spread in the view zenith and relative azimuth with respect to solar plane, solar zenith angle, BRDF models and wavelength of reflection. Analyzing the sensitivity of BRDF estimation errors to the variables allow simplification of the OSSE, to enable its use to rapidly evaluate formation architectures. A 6-satellite formation is shown to produce lower BRDF estimation errors, purely in terms of angular sampling as evaluated by the OSSE, than a single spacecraft with 9 forward-aft sensors. We demonstrate the ability to use OSSEs to design small satellite formations as complements to flagship mission data. The formations can fill angular sampling gaps and enable better BRDF products than currently possible.

  13. Observation of blue satellite bands and photoassociation at ultracold temperatures

    SciTech Connect

    Pichler, Marin; Qi Jianbing; Stwalley, William C.; Beuc, Robert; Pichler, Goran

    2006-02-15

    We have observed atomic line self-broadening of Cs near 7P{sub 3/2} and 7P{sub 1/2} atomic lines at ultracold temperatures using a magneto-optical trap and resonant ionization detection. We have observed blue satellite band features at detunings of 560 and 800 MHz, respectively, as well as sharp hyperfine-split photoassociative spectra on the red wings of each line and also on the blue wings. Possible explanations of these features are discussed.

  14. Precise Orbit Determination of GPS Satellites Using Phase Observables

    NASA Astrophysics Data System (ADS)

    Jee, Myung-Kook; Choi, Kyu-Hong; Park, Pil-Ho

    1997-12-01

    The accuracy of user position by GPS is heavily dependent upon the accuracy of satellite position which is usually transmitted to GPS users in radio signals. The real-time satellite position information directly obtained from broadcast ephimerides has the accuracy of 3 x 10 meters which is very unsatisfactory to measure 100km baseline to the accuracy of less than a few mili-meters. There are globally at present seven orbit analysis centers capable of generating precise GPS ephimerides and their orbit quality is of the order of about 10cm. Therefore, precise orbit model and phase processing technique were reviewed and consequently precise GPS ephimerides were produced after processing the phase observables of 28 global GPS stations for 1 day. Initial 6 orbit parameters and 2 solar radiation coefficients were estimated using batch least square algorithm and the final results were compared with the orbit of IGS, the International GPS Service for Geodynamics.

  15. A Comparison of Techniques for Scheduling Earth-Observing Satellites

    NASA Technical Reports Server (NTRS)

    Globus, Al; Crawford, James; Lohn, Jason; Pryor, Anna

    2004-01-01

    Scheduling observations by coordinated fleets of Earth Observing Satellites (EOS) involves large search spaces, complex constraints and poorly understood bottlenecks, conditions where evolutionary and related algorithms are often effective. However, there are many such algorithms and the best one to use is not clear. Here we compare multiple variants of the genetic algorithm: stochastic hill climbing, simulated annealing, squeaky wheel optimization and iterated sampling on ten realistically-sized EOS scheduling problems. Schedules are represented by a permutation (non-temperal ordering) of the observation requests. A simple deterministic scheduler assigns times and resources to each observation request in the order indicated by the permutation, discarding those that violate the constraints created by previously scheduled observations. Simulated annealing performs best. Random mutation outperform a more 'intelligent' mutator. Furthermore, the best mutator, by a small margin, was a novel approach we call temperature dependent random sampling that makes large changes in the early stages of evolution and smaller changes towards the end of search.

  16. Co-ordination of satellite and data programs: The committee on earth observation satellites' approach

    NASA Astrophysics Data System (ADS)

    Embleton, B. J. J.; Kingwell, J.

    1997-01-01

    Every year, an average of eight new civilian remote sensing satellite missions are launched. Cumulatively, over 250 such missions, each with a cost equivalent in current value to between US 100 million to US 1000 million, have been sponsored by space agencies in perhaps two dozen countries. These missions produce data and information products which are vital for informed decision making all over the world, on matters relating to natural resource exploitation, health and safety, sustainable national development, infrastructure planning, and a host of other applications. By contributing to better scientific understanding of global changes in the atmosphere, land surface, oceans and ice caps, these silently orbiting sentinels in the sky make it possible for governments and industries to make wiser environmental policy decisions and support the economic development needs of humanity. The international Committee on Earth Observation Satellites (CEOS) is the premier world body for co-ordinating and planning civilian satellite missions for Earth observation. Through its technical working groups and special task teams, it endeavours to: • maximise the international benefits from Earth observation satellites; and • harmonise practice in calibration, validation, data management and information systems for Earth observation. CEOS encompasses not only space agencies (data providers), but also the great international scientific and operational programs which rely on Earth science data from space. The user organisations affiliated with CEOS, together with the mission operators, attempt to reconcile user needs with the complex set of considerations — including national interests, cost, schedule — which affect the undertaking of space missions. Without such an internationally co-ordinated consensual approach, there is a much greater risk of waste through duplication, and of missed opportunity, or through the absence of measurements of some vital physical or biological

  17. Fast Emission Estimates in China Constrained by Satellite Observations (Invited)

    NASA Astrophysics Data System (ADS)

    Mijling, B.; van der A, R.

    2013-12-01

    Emission inventories of air pollutants are crucial information for policy makers and form important input data for air quality models. Unfortunately, bottom-up emission inventories, compiled from large quantities of statistical data, are easily outdated for an emerging economy such as China, where rapid economic growth changes emissions accordingly. Alternatively, top-down emission estimates from satellite observations of air constituents have important advantages of being spatial consistent, having high temporal resolution, and enabling emission updates shortly after the satellite data become available. Constraining emissions from concentration measurements is, however, computationally challenging. Within the GlobEmission project of the European Space Agency (ESA) a new algorithm has been developed, specifically designed for fast daily emission estimates of short-lived atmospheric species on a mesoscopic scale (0.25 × 0.25 degree) from satellite observations of column concentrations. The algorithm needs only one forward model run from a chemical transport model to calculate the sensitivity of concentration to emission, using trajectory analysis to account for transport away from the source. By using a Kalman filter in the inverse step, optimal use of the a priori knowledge and the newly observed data is made. We apply the algorithm for NOx emission estimates in East China, using the CHIMERE model together with tropospheric NO2 column retrievals of the OMI and GOME-2 satellite instruments. The observations are used to construct a monthly emission time series, which reveal important emission trends such as the emission reduction measures during the Beijing Olympic Games, and the impact and recovery from the global economic crisis. The algorithm is also able to detect emerging sources (e.g. new power plants) and improve emission information for areas where proxy data are not or badly known (e.g. shipping emissions). The new emission estimates result in a better

  18. Comparing soil moisture memory in satellite observations and models

    NASA Astrophysics Data System (ADS)

    Stacke, Tobias; Hagemann, Stefan; Loew, Alexander

    2013-04-01

    A major obstacle to a correct parametrization of soil processes in large scale global land surface models is the lack of long term soil moisture observations for large parts of the globe. Currently, a compilation of soil moisture data derived from a range of satellites is released by the ESA Climate Change Initiative (ECV_SM). Comprising the period from 1978 until 2010, it provides the opportunity to compute climatological relevant statistics on a quasi-global scale and to compare these to the output of climate models. Our study is focused on the investigation of soil moisture memory in satellite observations and models. As a proxy for memory we compute the autocorrelation length (ACL) of the available satellite data and the uppermost soil layer of the models. Additional to the ECV_SM data, AMSR-E soil moisture is used as observational estimate. Simulated soil moisture fields are taken from ERA-Interim reanalysis and generated with the land surface model JSBACH, which was driven with quasi-observational meteorological forcing data. The satellite data show ACLs between one week and one month for the greater part of the land surface while the models simulate a longer memory of up to two months. Some pattern are similar in models and observations, e.g. a longer memory in the Sahel Zone and the Arabian Peninsula, but the models are not able to reproduce regions with a very short ACL of just a few days. If the long term seasonality is subtracted from the data the memory is strongly shortened, indicating the importance of seasonal variations for the memory in most regions. Furthermore, we analyze the change of soil moisture memory in the different soil layers of the models to investigate to which extent the surface soil moisture includes information about the whole soil column. A first analysis reveals that the ACL is increasing for deeper layers. However, its increase is stronger in the soil moisture anomaly than in its absolute values and the first even exceeds the

  19. Satellite Observations of Desert Dust-induced Himalayan Snow Darkening

    NASA Technical Reports Server (NTRS)

    Gautam, Ritesh; Hsu, N. Christina; Lau, William K.-M.; Yasunari, Teppei J.

    2013-01-01

    The optically thick aerosol layer along the southern edge of the Himalaya has been subject of several recent investigations relating to its radiative impacts on the South Asian summer monsoon and regional climate forcing. Prior to the onset of summer monsoon, mineral dust from southwest Asian deserts is transported over the Himalayan foothills on an annual basis. Episodic dust plumes are also advected over the Himalaya, visible as dust-laden snow surface in satellite imagery, particularly in western Himalaya. We examined spectral surface reflectance retrieved from spaceborne MODIS observations that show characteristic reduction in the visible wavelengths (0.47 nm) over western Himalaya, associated with dust-induced solar absorption. Case studies as well as seasonal variations of reflectance indicate a significant gradient across the visible (0.47 nm) to near-infrared (0.86 nm) spectrum (VIS-NIR), during premonsoon period. Enhanced absorption at shorter visible wavelengths and the resulting VIS-NIR gradient is consistent with model calculations of snow reflectance with dust impurity. While the role of black carbon in snow cannot be ruled out, our satellite-based analysis suggests the observed spectral reflectance gradient dominated by dust-induced solar absorption during premonsoon season. From an observational viewpoint, this study underscores the importance of mineral dust deposition toward darkening of the western Himalayan snow cover, with potential implications to accelerated seasonal snowmelt and regional snow albedo feedbacks.

  20. Assessment of Global Annual Atmospheric Energy Balance from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Lin, Bing; Stackhouse, Paul; Minnis, Patrick; Wielicki, Bruce A.; Hu, Yongxiang; Sun, Wenbo; Fan, Tai-Fang (Alice); Hinkelman, Laura

    2008-01-01

    Global atmospheric energy balance is one of the fundamental processes for the earth's climate system. This study uses currently available satellite data sets of radiative energy at the top of atmosphere (TOA) and surface and latent and sensible heat over oceans for the year 2000 to assess the global annual energy budget. Over land, surface radiation data are used to constrain assimilated results and to force the radiation, turbulent heat, and heat storage into balance due to a lack of observation-based turbulent heat flux estimations. Global annual means of the TOA net radiation obtained from both direct measurements and calculations are close to zero. The net radiative energy fluxes into the surface and the surface latent heat transported into the atmosphere are about 113 and 86 Watts per square meter, respectively. The estimated atmospheric and surface heat imbalances are about -8 9 Watts per square meter, values that are within the uncertainties of surface radiation and sea surface turbulent flux estimates and likely systematic biases in the analyzed observations. The potential significant additional absorption of solar radiation within the atmosphere suggested by previous studies does not appear to be required to balance the energy budget the spurious heat imbalances in the current data are much smaller (about half) than those obtained previously and debated at about a decade ago. Progress in surface radiation and oceanic turbulent heat flux estimations from satellite measurements significantly reduces the bias errors in the observed global energy budgets of the climate system.

  1. Long-term observations of tropospheric NO2 from satellite

    NASA Astrophysics Data System (ADS)

    Richter, Andreas; Hilboll, Andreas; Noguchi, Katsuyuki; Leitao, Joana; Burrows, John P.

    Nitrogen oxides (NOx = NO + NO2 ) are key species in atmospheric chemistry. Together with volatile organic compounds they determine the amount of ozone present in the troposphere. Through the formation of nitric acid they are involved in acid rain formation and in addition they contribute to radiative forcing both directly and indirectly. As nitrogen dioxide adversely affects human health it is also regulated by environmental laws. While ground-based networks provide long-term data of surface concentrations of nitrogen oxides at high temporal resolution in many countries, truly global observations can only be performed from space. By using the Differential Optical Absorption Spectroscopy (DOAS) method on spectrally resolved UV/vis measurements of scattered sunlight, column amounts of NO2 can be determined from nadir satellite observations. With additional assumptions on stratospheric NO2 and the radiative transfer, the tropospheric NO2 amounts can be retrieved. In this work, satellite observations of NO2 from several sensors (GOME, SCIAMACHY, OMI, and GOME-2) are used to study the long-term evolution of tropospheric NO2 amounts on a global scale. A particular focus is on the comparison of results retrieved from the different sensors in times of overlapping measurements and the degree of consistency achieved in regions of both large and small pollution signals. The effects of sampling statistics, time of overpass and spatial resolution are discussed as well as the influence of clouds.

  2. Divergence of actual and reference evapotranspiration observations for irrigated sugarcane with windy tropical conditions

    NASA Astrophysics Data System (ADS)

    Anderson, R. G.; Wang, D.; Tirado-Corbalá, R.; Zhang, H.; Ayars, J. E.

    2015-01-01

    Standardized reference evapotranspiration (ET) and ecosystem-specific vegetation coefficients are frequently used to estimate actual ET. However, equations for calculating reference ET have not been well validated in tropical environments. We measured ET (ETEC) using eddy covariance (EC) towers at two irrigated sugarcane fields on the leeward (dry) side of Maui, Hawaii, USA in contrasting climates. We calculated reference ET at the fields using the short (ET0) and tall (ETr) vegetation versions of the American Society for Civil Engineers (ASCE) equation. The ASCE equations were compared to the Priestley-Taylor ET (ETPT) and ETEC. Reference ET from the ASCE approaches exceeded ETEC during the mid-period (when vegetation coefficients suggest ETEC should exceed reference ET). At the windier tower site, cumulative ETr exceeded ETEC by 854 mm over the course of the mid-period (267 days). At the less windy site, mid-period ETr still exceeded ETEC, but the difference was smaller (443 mm). At both sites, ETPT approximated mid-period ETEC more closely than the ASCE equations ((ETPT-ETEC) < 170 mm). Analysis of applied water and precipitation, soil moisture, leaf stomatal resistance, and canopy cover suggest that the lower observed ETEC was not the result of water stress or reduced vegetation cover. Use of a custom-calibrated bulk canopy resistance improved the reference ET estimate and reduced seasonal ET discrepancy relative to ETPT and ETEC in the less windy field and had mixed performance in the windier field. These divergences suggest that modifications to reference ET equations may be warranted in some tropical regions.

  3. Recent state of the Aral sea from regular satellite observations.

    NASA Astrophysics Data System (ADS)

    Stanichny, S.; Davidov, A.; Djenidi, S.; Horstmann, U.; Stanichnaya, R.; Soloviev, D.

    The Aral Sea disaster is one of the most significant examples of ecological catastrophe caused by mismanagement of water resources. Aral sea level dropped on 22 meters for the last 35 years. The sea separated in to two independent parts , the Large Sea(Southern) and the Small Sea (Northern), loosing more than 90% of its original water masses. After the collapse of the former Soviet Union, satellite retrieved data became the main source of information on this perishing system. Regular observations from AVHRR, SeaWiFS, MODIS and ASTER satellite sensors were used for our investigations. Sea surface temperature (SST) data of the AVHRR sensor and digital bottom map topography were used for sea level drop calculations. The Sea level defined as the digital map isobate corresponds quite well to the satellite derived coastline for the Eastern part of the Large Sea with a bottom slope of ˜ 0.00015. For the period 1989-2002 the sea level of the Large Sea dropped on 9.2 meters. However in 2003 the sea level remained stable. This stabilisation was due to an increase of water output of the rivers Amu--Darya and Syr-Darya in 2003. High resolution ASTER data showed that the main amount of Syr-Darya waters is discharged into the Large Sea. The dried bottom area now covers more than 45000 km2. On the base of AVHRR-SST data the temperature regime for different parts of the Aral Sea was calculated for the years 2002-2003. The annual amplitude of the SST variation reaches 37° C for the open waters. The observed minimum freezing point was -7° C due to very high salinity. Estimations from satellite retrieved freezing points show an increase of salinity up to 10% in the Eastern part of the Large Sea. It is almost paradox that on satellite images the ice appears warmer than the water. Strong variations of the water temperature (up to 5° C) within a few days could be observed from April to August and could be related to wind induced mixing. SeaWiFS ocean colour data were used for the

  4. Alaskan mountain glacial melting observed by satellite gravimetry

    NASA Astrophysics Data System (ADS)

    Chen, J. L.; Tapley, B. D.; Wilson, C. R.

    2006-08-01

    We use satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) as an indication of mass change to study potential long-term mountain glacial melting in southern Alaska and West Canada. The first 3.5 yr of GRACE monthly gravity data, spanning April 2002-November 2005, show a prominent glacial melting trend in the mountain regions around the Gulf of Alaska (GOA). GRACE-observed surface mass changes correlate remarkably well with available mass balance data at Gulkana and Wolverine, two benchmark glaciers of the U.S. Geological Survey (USGS), although the GRACE signals are smaller in magnitude. In addition, terrestrial water storage (TWS) changes estimated from an advanced land surface model show significant mass loss in this region during the same period. After correcting for the leakage errors and removing TWS contributions using model estimates, we conclude that GRACE-observed glacial melting in the GOA mountain region is equivalent to ˜ - 101 ± 22 km 3/yr, which agrees quite well with the assessment of ˜ - 96 ± 35 km 3/yr based on airborne laser altimetry data, and is consistent with an earlier estimate based on the first 2 yr of GRACE data. This study demonstrates the significant potentials of satellite gravity measurements for monitoring mountain glacial melting and regional climate change.

  5. Eclipses of the inner satellites of Jupiter observed in 2015

    NASA Astrophysics Data System (ADS)

    Saquet, E.; Emelyanov, N.; Colas, F.; Arlot, J.-E.; Robert, V.; Christophe, B.; Dechambre, O.

    2016-06-01

    Aims: During the 2014-2015 campaign of mutual events, we recorded ground-based photometric observations of eclipses of Amalthea (JV) and, for the first time, Thebe (JXIV) by the Galilean moons. We focused on estimating whether the positioning accuracy of the inner satellites determined with photometry is sufficient for dynamical studies. Methods: We observed two eclipses of Amalthea and one of Thebe with the 1 m telescope at Pic du Midi Observatory using an IR filter and a mask placed over the planetary image to avoid blooming features. A third observation of Amalthea was taken at Saint-Sulpice Observatory with a 60 cm telescope using a methane filter (890 nm) and a deep absorption band to decrease the contrast between the planet and the satellites. After background removal, we computed a differential aperture photometry to obtain the light flux, and followed with an astrometric reduction. Results: We provide astrometric results with an external precision of 53 mas for the eclipse of Thebe, and 20 mas for that of Amalthea. These observation accuracies largely override standard astrometric measurements. The (O - C)s for the eclipse of Thebe are 75 mas on the X-axis and 120 mas on the Y-axis. The (O - C)s for the total eclipses of Amalthea are 95 mas and 22 mas, along the orbit, for two of the three events. Taking into account the ratio of (O - C) to precision of the astrometric results, we show a significant discrepancy with the theory established by Avdyushev and Ban'shikova in 2008, and the JPL JUP 310 ephemeris. Three of the four eclipse observations where recorded at the 1 m telescope of Pic du Midi Observatory (S2P), the other at Saint-Sulpice Observatory.

  6. Prospects for satellite and space debris observations with Pi of the Sky

    NASA Astrophysics Data System (ADS)

    Ćwiek, A.; Batsch, T.; Majcher, A.; Mankiewicz, L.; Wrochna, G.; ZadroŻny, A.; Żarnecki, A. F.

    2015-09-01

    Pi of the Sky is a system of wide field-of-view robotic telescopes designed for observations of short timescale astrophysical phenomena, especially for prompt optical GRB emission. The apparatus designed for autonomous operation follows the predefined observing strategy and adopts to the actual running conditions, monitoring a large part of the sky with time resolution of the order of 1 - 10 seconds and range 12m-13m. Observation strategy and system design was successfully tested with a prototype detector in Chile and starting 2013 the final Pi of the Sky detector system in operation at the INTA El Arenosillo Test Centre in Spain. For the analysis of the data from a wide field-of-view system a set of dedicated algorithms have been developed, which allowed us to reduce photometry uncertainty for bright stars to the level of 0.015m- 0.02m. Design of the Pi of the Sky telescopes allows also for measurements of near-Earth objects as comets, asteroids, satellites and space debris. Precise determination of the orbit parameters of the geostationary satellites is possible when using a parallax measured with simultaneous observations from Spain and Chile. Dedicated tests have been performed recently to verify system capabilities for observation of objects on lower orbits, moving at higher speeds. First results are discussed in this contribution.

  7. LCROSS: Lunar CRater Observation and Sensing Satellite Project

    NASA Technical Reports Server (NTRS)

    Marmie, John

    2010-01-01

    This slide presentation reviews the success of the Lunar Crater Observation and Sensing Satellite (LCROSS) project. The LCROSS mission science goals was to: (1) Confirm the presence or absence of water ice in a permanently shadowed region on the Moon (2) Identify the form/state of hydrogen observed by at the lunar poles (3) Quantify, if present, the amount of water in the lunar regolith, with respect to hydrogen concentrations (4) Characterize the lunar regolith within a permanently shadowed crater on the Moon. The mission confirmed the presence of water ice on the moon by impacting a part of the spent Centaur upper stage into the Cabeus crater.. The presentation includes pictures of the development of the spacecraft, testing, launch, impact site, impact and a section of what the author called "Lunacy" which showed joking cartoons.

  8. Satellite microwave observations of the Utah Great Salt Lake Desert

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.; Dellwig, L. F.; Schmugge, T. J.

    1975-01-01

    Microwave data acquired over the Great Salt Lake Desert by sensors aboard Skylab and Nimbus 5 indicate that microwave emission and backscatter were strongly influenced by contributions from subsurface layers of sediment saturated with brine. This phenomenon was observed by Skylab's S-194 radiometer operating at 1.4 GHz, S-193 RADSCAT (Radiometer-Scatterometer) operating at 13.9 GHz and the Nimbus 5 ESMR (Electrically Scanning Microwave Radiometer) operating at 19.35 GHz. The availability of ESMR data over an 18 month period allowed an investigation of temporal variations. Aircraft 1.4 GHz radiometer data acquired two days after one of the Skylab passes confirm the satellites observations. Data from the ESMR revealed similar responses over the Bolivian deserts, which have geologic features similar to those of the Utah desert.

  9. Satellite Observation Highlights of the 2010 Russian Wildfires

    NASA Technical Reports Server (NTRS)

    Witte, Jacquelyn C.; Douglass, Anne R.; Duncan, Bryan N.; daSilva, Arlindo; Torres, Omar

    2010-01-01

    From late-July through mid-August 2010, wildfires raged in western Russia. The resulting thick smoke and biomass burning products were transported over the highly populated Moscow city and surrounding regions, seriously impairing visibility and affecting human health. We demonstrate the uniqueness of the 2010 Russian wildfires by using satellite observations from NASA's Earth Observing System (EOS) platforms. Over Moscow and the region of major fire activity to the southeast, we calculate unprecedented increases in the MODIS fire count record of 178 %, an order of magnitude increase in the MODIS fire radiative power (308%) and OMI absorbing aerosols (255%), and a 58% increase in AIRS total carbon monoxide (CO). The exceptionally high levels of CO are shown to be of comparable strength to the 2006 El Nino wildfires over Indonesia. Both events record CO values exceeding 30x10(exp 7) molec/ square cm.

  10. Subtropical Gyre Variability Observed by Ocean Color Satellites

    NASA Technical Reports Server (NTRS)

    McClain, Charles R.; Signorini, Sergio R.; Christian, James R.

    2002-01-01

    The subtropical gyres of the world are extensive, coherent regions that occupy about 40% of the surface of the earth. Once thought to be homogeneous and static habitats, there is increasing evidence that mid-latitude gyres exhibit substantial physical and biological variability on a variety of time scales. While biological productivity within these oligotrophic regions may be relatively small, their immense size makes their total contribution significant. Global distributions of dynamic height derived from satellite altimeter data, and chlorophyll concentration derived from satellite ocean color data, show that the dynamic center of the gyres, the region of maximum dynamic height where the thermocline is deepest, does not coincide with the region of minimum chlorophyll concentration. The physical and biological processes by which this distribution of ocean properties is maintained, and the spatial and temporal scales of variability associated with these processes, are analyzed using global surface chlorophyll-a concentrations, sea surface height, sea surface temperature and surface winds from operational satellite and meteorological sources, and hydrographic data from climatologies and individual surveys. Seasonal and interannual variability in the areal extent of the subtropical gyres are examined using 8 months (November 1996 - June 1997) of OCTS and nearly 5 years (September 1997 - June 02) of SeaWiFS ocean color data and are interpreted in the context of climate variability and measured changes in other ocean properties (i.e., wind forcing, surface currents, Ekman pumping, and vertical mixing). The North Pacific and North Atlantic gyres are observed to be shrinking over this period, while the South Pacific, South Atlantic, and South Indian Ocean gyres appear to be expanding.

  11. Satellite-based Observation of Arctic River Dynamics

    NASA Astrophysics Data System (ADS)

    Overeem, I.; Brakenridge, R.; Hudson, B.

    2015-12-01

    One of the indicators of a warming Arctic region is an intensification of the hydrological cycle, with increasing permafrost and glacial melt and possibly more precipitation resulting in higher river runoff. Indeed, a significant increase of nearly 10% in annual river flux has been observed in 13 major rivers throughout the entire Arctic region over the last 30 years. However, direct measurements are extremely sparse for 100's of smaller-scale tundra river systems, as well as for proglacial rivers around the Greenland Ice Sheet margin. Observations at in-situ gauging stations are hampered by seasonal ice coverage, break-up and freeze-up dynamics, unstable banks, and difficult access. To overcome such difficulties, we develop remote-sensing based river discharge measurement techniques using a variety of satellite sensors, including reflectance in the near-infrared band of MODIS, LANDSAT, and brightness temperature from the passive microwave sensors AMSR-E and AMSR-2. We use varying inundation of the river channel and floodplain throughout a season to quantify the changing Arctic river flux. A new approach to detect river ice break up in spring has been developed, and is now undergoing validation. To calibrate the remote sensing signal to daily river discharge, we employ either in-situ short observation records, or a numerical distributed hydrological model driven by daily reanalysis climate data. Quantitative reconstructions of meltwater fluxes in rivers along the Greenland Ice Sheet margin obtained so far show a dampened response of these rivers to Greenland Ice Sheet melt. Techniques are now deployed to map river dynamics along the Chukchi Sea and Beaufort Sea coasts, and show shifts in break-up dynamics and flooding patterns. Once calibrated, satellite-based reconstructions have the potential to lengthen short observational records to a ~15 year timespan.

  12. Actual and prescribed energy and protein intakes for very low birth weight infants: An observational study

    NASA Astrophysics Data System (ADS)

    Allevato, Anthony J.

    Objectives: To determine (1) whether prescribed and delivered energy and protein intakes during the first two weeks of life met Ziegler's estimated requirements for Very Low Birth Weight (VLBW) infants, (2) if actual energy during the first week of life correlated with time to regain birth weight and reach full enteral nutrition (EN) defined as 100 kcal/kg/day, (3) if growth velocity from time to reach full EN to 36 weeks' postmenstrual age (PMA) met Ziegler's estimated fetal growth velocity (16 g/kg/day), and (4) growth outcomes at 36 weeks' PMA. Study design: Observational study of feeding, early nutrition and early growth of 40 VLBW infants <30 weeks GA at birth in three newborn intensive care units NICUs. Results: During the first week of life, the percentages of prescribed and delivered energy (69% [65 kcal/kg/day]) and protein (89% [3.1 g/kg/day]) were significantly less than theoretical estimated requirements. Delivered intakes were 15% less than prescribed because of numerous interruptions in delivery and medical complications. During the second week, the delivered intakes of energy (90% [86 kcal/kg/day]) and protein (102% [3.5 g/kg/day]) improved although the differences between prescribed and delivered were consistently 15%. Energy but not protein intake during the first week was significantly related to time to reach full EN. Neither energy nor protein intake significantly correlated with days to return to birth weight. The average growth velocity from the age that full EN was attained to 36 weeks' PMA (15 g/kg/day) was significantly less than the theoretical estimated fetal growth velocity (16 g/kg/day) (p<0.03). A difference of 1 g/kg/day represents a total deficit of 42 - 54 grams over the course of a month. At 36 weeks' PMA, 53% of the VLBW infants had extrauterine growth restriction, or EUGR (<10th percentile) on the Fenton growth grid and 34% had EUGR on the Lubchenco growth grid. Conclusions: The delivered nutrient intakes were consistently less

  13. An Examination of Intertidal Temperatures Through Remotely Sensed Satellite Observations

    NASA Astrophysics Data System (ADS)

    Lakshmi, V.

    2010-12-01

    MODIS Aqua and Terra satellites produce both land surface temperatures and sea surface temperatures using calibrated algorithms. In this study, the land surface temperatures were retrieved during clear-sky (non-cloudy) conditions at a 1 km2 resolution (overpass time at 10:30 am) whereas the sea surface temperatures are also retrieved during clear-sky conditions at approximately 4 km resolution (overpass time at 1:30 pm). The purpose of this research was to examine remotely sensed sea surface (SST), intertidal (IST), and land surface temperatures (LST), in conjunction with observed in situ mussel body temperatures, as well as associated weather and tidal data. In Strawberry Hill, Oregon, it was determined that intertidal surface temperatures are similar to but distinctly different from land surface temperatures although influenced by sea surface temperatures. The air temperature and differential heating throughout the day, as well as location in relation to the shore, can greatly influence the remotely sensed surface temperatures. Therefore, remotely sensed satellite data is a very useful tool in examining intertidal temperatures for regional climatic changes over long time periods and may eventually help researchers forecast expected climate changes and help determine associated biological implications.

  14. International Collaboration in Satellite Observations for Disaster Management

    NASA Technical Reports Server (NTRS)

    Duda, Kenneth A.; Abrams, Michael

    2012-01-01

    When lives are threatened or lost due to catastrophic disasters, and when massive financial impacts are experienced, international emergency response teams rapidly mobilize to provide urgently required support. Satellite observations of affected areas often provide essential insight into the magnitude and details of the impacts. The large cost and high complexity of developing and operating satellite flight and ground systems encourages international collaboration in acquiring imagery for such significant global events in order to speed delivery of critical information to help those affected, and optimize spectral, spatial, and temporal coverage of the areas of interest. The International Charter-Space and Major Disasters was established to enable such collaboration in sensor tasking during times of crisis and is often activated in response to calls for assistance from authorized users. Insight is provided from a U.S. perspective into sensor support for Charter activations and other disaster events through a description of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), which has been used to support emergency situations for over a decade through its expedited tasking and near real-time data delivery capabilities. Examples of successes achieved and challenges encountered in international collaboration to develop related systems and fulfill tasking requests suggest operational considerations for new missions as well as areas for future enhancements.

  15. Observation of suspended sediments in Mobile Bay, Alabama from satellite

    USGS Publications Warehouse

    Stumpf, Richard P.

    1991-01-01

    As part of a comprehensive geologic study of coastal Alabama and Mississippi, the U.S. Geological Survey is investigating coastal sediment transport in Mobile Bay and the adjacent shelf. Satellite imagery from the NOAA AVHRR is being used to provide data on the variability of spatial patterns in the near-surface suspended sediment concentration. This imagery is processed using atmospheric corrections to remove haze and Rayleigh radiance in order to obtain water reflectances; the reflectances are than converted to approximate sediment concentrations using standard relationships between water reflectance and in situ sediment concentrations. A series of images from early 1990 shows rapid changes in sediment concentrations in response to high river flow of the Alabama-Tombigbee river system. During these times, suspended sediment tends to flow out Mobile Bay without mixing into the eastern lobe of the Bay (Bon Secour Bay). The sediment concentration field also appears to be disturbed by the main ship channel. The sediment plume extends more than 60 km offshore after the peak flow event. One wind event in December 1989 was identified as increasing sediment concentration in the Bay. It is not believed that such an event has been previously observed from satellite.

  16. Arctic Sea ice studies with passive microwave satellite observations

    NASA Technical Reports Server (NTRS)

    Cavalieri, D. J.

    1988-01-01

    The objectives of this research are: (1) to improve sea ice concentration determinations from passive microwave space observations; (2) to study the role of Arctic polynyas in the production of sea ice and the associated salinization of Arctic shelf water; and (3) to study large scale sea ice variability in the polar oceans. The strategy is to analyze existing data sets and data acquired from both the DMSP SSM/I and recently completed aircraft underflights. Special attention will be given the high resolution 85.5 GHz SSM/I channels for application to thin ice algorithms and processes studies. Analysis of aircraft and satellite data sets is expected to provide a basis for determining the potential of the SSM/I high frequency channels for improving sea ice algorithms and for investigating oceanic processes. Improved sea ice algorithms will aid the study of Arctic coastal polynyas which in turn will provide a better understanding of the role of these polynyas in maintaining the Arctic watermass structure. Analysis of satellite and archived meteorological data sets will provide improved estimates of annual, seasonal and shorter-term sea ice variability.

  17. Earth observing satellite: Understanding the Earth as a system

    NASA Technical Reports Server (NTRS)

    Soffen, Gerald

    1990-01-01

    There is now a plan for global studies which include two very large efforts. One is the International Geosphere/Biosphere Program (IGBP) sponsored by the International Council of Scientific Unions. The other initiative is Mission to Planet Earth, an unbrella program for doing three kinds of space missions. The major one is the Earth Observation Satellite (EOS). EOS is large polar orbiting satellites with heavy payloads. Two will be placed in orbit by NASA, one by the Japanese and one or two by ESA. The overall mission measurement objectives of EOS are summarized: (1) the global distribution of energy input to and energy output from the Earth; (2) the structure, state variables, composition, and dynamics of the atmosphere from the ground to the mesopause; (3) the physical and biological structure, state, composition, and dynamics of the land surface, including terrestrial and inland water ecosystems; (4) the rates, important sources and sinks, and key components and processes of the Earth's biogeochemical cycles; (5) the circulation, surface temperature, wind stress, sea state, and the biological activity of the oceans; (6) the extent, type, state, elevation, roughness, and dynamics of glaciers, ice sheets, snow and sea ice, and the liquid equivalent of snow in the global cryosphere; (7) the global rates, amounts, and distribution of precipitation; and (8) the dynamic motions of the Earth (geophysics) as a whole, including both rotational dynamics and the kinematic motions of the tectonic plates.

  18. Antartic sea ice, 1973 - 1976: Satellite passive-microwave observations

    NASA Technical Reports Server (NTRS)

    Zwally, H. J.; Comiso, J. C.; Parkinson, C. L.; Campbell, W. J.; Carsey, F. D.; Gloersen, P.

    1983-01-01

    Data from the Electrically Scanning Microwave Radiometer (ESMR) on the Nimbus 5 satellite are used to determine the extent and distribution of Antarctic sea ice. The characteristics of the southern ocean, the mathematical formulas used to obtain quantitative sea ice concentrations, the general characteristics of the seasonal sea ice growth/decay cycle and regional differences, and the observed seasonal growth/decay cycle for individual years and interannual variations of the ice cover are discussed. The sea ice data from the ESMR are presented in the form of color-coded maps of the Antarctic and the southern oceans. The maps show brightness temperatures and concentrations of pack ice averaged for each month, 4-year monthly averages, and month-to-month changes. Graphs summarizing the results, such as areas of sea ice as a function of time in the various sectors of the southern ocean are included. The images demonstrate that satellite microwave data provide unique information on large-scale sea ice conditions for determining climatic conditions in polar regions and possible global climatic changes.

  19. Satellite Observations of Solar Irradiance and Sun-Climate Impacts

    NASA Technical Reports Server (NTRS)

    Cahalan, R.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Solar activity is now near its maximum, with events such as the 2001 "Bastille Day Event", a Coronal Mass Ejection which merited a full session at AGO'S annual meeting - and two major sunspot groupings earlier this year, with associated variations in TSI (Total Solar Irradiance). We discuss recent satellite measurements of TSI by ACRIM 2 and 3 And Virgo, and new precision observations of TSI and SSI (Solar Spectral Irradiance) expected from the SORCE mission, planned to launch in fall 2002. SSG has been added to TSI as a required EOS and NPOESS measurement because different spectral components provide energy inputs to different components of the climate system - UV into upper atmosphere and ozone, IR into lower atmosphere and clouds, and Visible into the biosphere. Succeeding satellite missions being planned for 2006 and 2010 will continue to monitor both TSI and SSI. We summarize current ideas about the potential impact of solar variability on Earth's climate on time scales from days to decades to centuries.

  20. Satellite Observations of Solar Irradiance and Sun-Climate Impacts

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Solar activity is now near its maximum, with events such as the 2001 "Bastille Day Event", a Coronal Mass Ejection which merited a full session at AGUs annual meeting - and two major sunspot groupings earlier this year, with associated variations in TSI (Total Solar Irradiance). We discuss recent satellite measurements of TSI by ACRIM 2 and 3 and Virgo, and new precision observations of TSI and SSI (Solar Spectral Irradiance) expected from the SORCE mission, planned to launch in fall 2002. SSI has been added to TSI as a required EOS and NPOESS measurement because different spectral components provide energy inputs to different components of the climate system - UV into upper atmosphere and ozone, IR into lower atmosphere and clouds, and Visible into the biosphere. Succeeding satellite missions being planned for 2006 and 2010 will continue to monitor both TSI and SSI. We summarize current ideas about the potential impact of solar variability on Earth's climate on time scales from days to decades to centuries.

  1. Divergence of actual and reference evapotranspiration observations for irrigated sugarcane with windy tropical conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Standardized reference evapotranspiration (ET) and ecosystem-specific vegetation coefficients are frequently used to estimate actual ET. However, equations for calculating reference ET have not been well validated in more humid environments. We measured ET (ETEC) using Eddy Covariance (EC) towers a...

  2. Actual and Prescribed Energy and Protein Intakes for Very Low Birth Weight Infants: An Observational Study

    ERIC Educational Resources Information Center

    Abel, Deborah Marie

    2012-01-01

    Objectives: To determine (1) whether prescribed and delivered energy and protein intakes during the first two weeks of life met Ziegler's estimated requirements for Very Low Birth Weight (VLBW) infants, (2) if actual energy during the first week of life correlated with time to regain birth weight and reach full enteral nutrition (EN) defined as…

  3. Obs4MIPS: Satellite Observations for CMIP6 Model Evaluation

    NASA Astrophysics Data System (ADS)

    Ferraro, R.; Waliser, D. E.; Gleckler, P. J.; Taylor, K. E.; Eyring, V.

    2014-12-01

    This poster will review the current status of the obs4MIPs project, whose purpose is to provide a limited collection of well-established and documented datasets for comparison with Earth system models (https://www.earthsystemcog.org/projects/obs4mips/). These datasets have been reformatted to correspond with the CMIP5 model output requirements, and include technical documentation specifically targeted for their use in model otput evaluation. There are currently over 50 datasets containing observations that directly correspond to CMIP5 model output variables. We will review the results and recommendations from the recent obs4MIPs - CMIP6 planning meeting, which gathered over 50 experts in satellite observations and CMIP modeling, to assess the needed observations to support the next round of CMIP experiments. The recommendations address key issues regarding the inclusion of higher frequency datasets (both observations and model output), the need for error and bias characterization, the inclusion of reanalysis, and support for observation simulators. An update on the governance for the obs4MIPs project and recent usage statistics will also be presented.

  4. Sea Ice and Ice Temperature Variability as Observed by Microwave and Infrared Satellite Data

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Recent reports of a retreating and thinning sea ice cover in the Arctic have pointed to a strong suggestion of significant warming in the polar regions. It is especially important to understand what these reports mean in light of the observed global warning and because the polar regions are expected to be most sensitive to changes in climate. To gain insight into this phenomenon, co-registered ice concentrations and surface temperatures derived from two decades of satellite microwave and infrared data have been processed and analyzed. While observations from meteorological stations indicate consistent surface warming in both regions during the last fifty years, the last 20 years of the same data set show warming in the Arctic but a slight cooling in the Antarctic. These results are consistent with the retreat in the Arctic ice cover and the advance in the Antarctic ice cover as revealed by historical satellite passive microwave data. Surface temperatures derived from satellite infrared data are shown to be consistent within 3 K with surface temperature data from the limited number of stations. While not as accurate, the former provides spatially detailed changes over the twenty year period. In the Arctic, for example, much of the warming occurred in the Beaufort Sea and the North American region in 1998 while slight cooling actually happened in parts of the Laptev Sea and Northern Siberia during the same time period. Big warming anomalies are also observed during the last five years but a periodic cycle of about ten years is apparent suggesting a possible influence of the North Atlantic Oscillation. In the Antarctic, large interannual and seasonal changes are also observed in the circumpolar ice cover with regional changes showing good coherence with surface temperature anomalies. However, a mode 3 is observed to be more dominant than the mode 2 wave reported in the literature. Some of these spatial and temporal changes appear to be influenced by the Antarctic

  5. Status and trends of small satellite missions for Earth observation

    NASA Astrophysics Data System (ADS)

    Sandau, Rainer

    2010-01-01

    Small satellites for remote sensing—how is a small satellite characterized, what is the basis for it, what are the trends, and what the application areas. The paper gives some insights in related facts and trends. The requirements concerning spatial, spectral and time resolution for the manifold application areas indicate the wide range of potential application for small satellites. Most of them can be covered using small satellites because of their already proven high performance capabilities in terms of spatial and spectral resolution. The implementation of satellite constellations to increase the time resolution and ground coverage is a unique feature of small, low-cost satellites. One payload example (BIRD) is given to show the potential of small satellites to give even better results compared to the existing fleet of larger satellites. More examples are given for small satellite constellations and formations in order to show how small satellites can be used to improve time resolution and ground coverage as well as to solve tasks which a single satellite is unable to solve.

  6. Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites

    NASA Technical Reports Server (NTRS)

    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.

  7. Unusual satellite data: A black hole?. [International Ultraviolet Explorer observations

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Data obtained by the NASA-launched European Space Agency's International Ultraviolet Explorer satellite suggests the possibility of a massive black hole at the center of some globular clusters (star groups) in our galaxy. Six of these clusters, three of them X-ray sources, were closely examined. Onboard short wavelength UV instrumentation penetrated the background denseness of the clusters 15,000 light years away where radiation, probably from a group of 10 to 20 bright blue stars orbiting the core, was observed. The stars may well be orbiting a massive black hole the size of 1,000 solar systems. The existence of the black hole is uncertain. The dynamics of the stars must be studied first to determine how they rotate in relation to the center of the million-star cluster. This may better indicate what provides the necessary gravitational pull that holds them in orbit.

  8. Interactive analysis of a large aperture Earth observations satellite

    NASA Technical Reports Server (NTRS)

    Wright, R. L.; Deryder, D. D.; Ferebee, M. J., Jr.; Smith, J. C.

    1983-01-01

    A system level design and analysis has been conducted on an Earth Observation Satellite (EOS) system using the Interactive Design and Evaluation of Advanced Spacecraft (IDEAS) computer-aided design and analysis program. The IDEAS program consists of about 40 user-friendly technical modules and an interactive graphics display. The reflector support system and feed mast of the EOS spacecraft are constructed with box-truss structural concept, a lattice configuration which can be packaged for delivery in a single Shuttle flight and deployed in orbit. The deployed spacecraft consists of a 120-m by 60-m parabolic focal axis. The spacecraft was modeled for structural, thermal, and control systems analysis and structural elements were designed. On-orbit dynamic and thermal loading analyses were conducted; spacecraft weights and developmental and first unit costs were determined.

  9. Planet/magnetosphere/satellite couplings: Observations from the moon

    NASA Astrophysics Data System (ADS)

    Prange, Renee

    1994-06-01

    The general characteristics of planetary magnetospheres depend upon a few key parameters, such as the magnetic dipole strength, the planetary rotation rate, and the strength of the internal plasma sources (satellites, rings, ionosphere). The present knowledge of the acceleration and of the large scale circulation of plasma in these magnetospheres is still rather poor. Plasma and energetic particle losses occur largely through precipitation into the atmosphere along magnetic field lines, giving rise to the planetary aurorae. These losses can be initiated by various kinds of magnetospheric processes, and, if clearly understood, could give major insights into the physics of the global magnetospheric system. After a brief comparative review of the planetary magnetospheres, it will be shown how our understanding of their dynamics could benefit from increased instrumental performances in terms of remote sensing in the X rays, UV to IR, and radio wavelength range, and what breakthroughs could be expected from lunar based observations.

  10. A web-based tool that combines satellite and weather station observations to support irrigation scheduling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract: The Satellite Irrigation Management Support (SIMS) project combines NASA's Terrestrial Observation and Prediction System (TOPS), Landsat and MODIS satellite imagery, and reference evapotranspiration from surface weather station networks to map daily crop irrigation demand in California in ...

  11. Ground and satellite observations of auroral fragmentation into patches

    NASA Astrophysics Data System (ADS)

    Shiokawa, Kazuo; Nishi, Katsuki

    2016-07-01

    We review characteristic auroral fragmentation which is the process by which uniform aurora is broken into several fragments to form auroral patches, based on the all-sky camera observations at Tromsoe, Norway and THEMIS chain in Canada. The auroral fragmentation occurs as finger-like structures developing predominantly in meridional direction with speeds of several tens m/s and scale sizes of several tens kilometers without any shearing motion. These features suggest that pressure-driven instability in the balance between the earthward magnetic-tension force and the tailward pressure gradient force in the magnetosphere is the main driving force of the auroral fragmentation. Thus, these observations indicate that auroral fragmentation associated with pressure-driven instability is a process that creates auroral patches. Auroral fragmentation is seen from midnight to dawn local time and usually appears at the beginning of the substorm recovery phase, near the low latitude boundary of the auroral region. One example of plasma and magnetic field observations by the THEMIS satellite in the conjugate magnetosphere shows diamagnetic anti-phase variations of magnetic and plasma pressures with time scales of several to tens minutes associated with the auroral fragmentation. This observation also supports the idea of pressure-driven instability to cause the auroral fragmentation into patches.

  12. Earth observations satellite data policy: Process and outcome

    SciTech Connect

    Shaffer, L.R.

    1994-12-31

    The National Aeronautics and Space Administration (NASA) develops, launches, and operates satellites to observe and monitor the Earth and its environment. This study categorizes each program based on the relationship between NASA and external organizations. A program can be an autonomous mission undertaken for NASA`s own constituency, or it can involve a client agency or a partner. These relationships affect how data policy decisions are made and implemented, and how the valuable output of NASA`s Earth observations satellites is managed. The process in NASA for determining which programs will be approved is very informal. Ideas and concepts surface and reach the consciousness of NASA management; if sufficient support is achieved, a proposal can move to the feasibility study phase and from there become an approved and funded mission. The handling of data can be an important consideration in generating political support for program approval. Autonomous programs tend to have decisions made at lower levels and documented informally or not at all. Data policy is part of routine implementation of programs and does not generally rise to the visibility of the agency head or congressional staff or the Executive Office of the President. Responsibility for data management for autonomous missions is retained at NASA centers. Client programs involve higher level decision makers, and are the subject of political interest because they cross agency boundaries. The data policy process includes presidential statements on data access. As part of the client relationship, NASA often provides resources to the client for data handling and analysis, and shares these responsibilities. Data policy for partner programs is the result of bargaining between the partners, either foreign government agencies or private companies.

  13. Observing convection with satellite, radar, and lightning measurements

    NASA Astrophysics Data System (ADS)

    Hamann, Ulrich; Nisi, Luca; Clementi, Lorenzo; Ventura, Jordi Figueras i.; Gabella, Marco; Hering, Alessandro M.; Sideris, Ioannis; Trefalt, Simona; Germann, Urs

    2015-04-01

    Heavy precipitation, hail, and wind gusts are the fundamental meteorological hazards associated with strong convection and thunderstorms. The thread is particularly severe in mountainous areas, e.g. it is estimated that on average between 50% and 80% of all weather-related damage in Switzerland is caused by strong thunderstorms (Hilker et al., 2010). Intense atmospheric convection is governed by processes that range from the synoptic to the microphysical scale and are considered to be one of the most challenging and difficult weather phenomena to predict. Even though numerical weather prediction models have some skills to predict convection, in general the exact location of the convective initialization and its propagation cannot be forecasted by these models with sufficient precision. Hence, there is a strong interest to improve the short-term forecast by using statistical, object oriented and/or heuristic nowcasting methods. MeteoSwiss has developed several operational nowcasting systems for this purpose such as TRT (Hering, 2008) and COALITION (Nisi, 2014). In this contribution we analyze the typical development of convection using measurements of the Swiss C-band Dual Polarization Doppler weather radar network, the MSG SEVIRI satellite, and the Météorage lighting network. The observations are complemented with the analysis and forecasts of the COSMO model. Special attention is given to the typical evolutionary stages like the pre-convective environment, convective initiation, cloud top glaciation, start, maximum, and end of precipitation and lightning activity. The pre-convective environment is examined using instability indices derived from SEVIRI observations and the COSMO forecasts. During the early development satellite observations are used to observe the rise of the cloud top, the growth of the cloud droplet or crystals, and the glaciation of the cloud top. SEVIRI brightness temperatures, channel differences, and temporal trends as suggested by

  14. [Contradiction and intention of actual situation and statistical observation on home custody of mental patients].

    PubMed

    Kanekawa, Hideo

    2012-01-01

    Actual Situation and Statistical Observation on Home Custody of Mental Patients (1918) by Kure and Kashida has diverse content but contains many contradictions. This book is a record of investigations performed by 15 psychiatrists regarding home custody of mental patients in 15 prefectures between 1910 and 1916. The book is written in archaic Japanese and contains a mixture of old Kanji characters and Katakana, so few people have read the entire book in recent years. We thoroughly read the book over 2 years, and presented the results of our investigation and analysis. The contents were initially published in Tokyo Journal of Medical Sciences as a series of 4 articles, and published as a book in 1918. The Department of the Interior distributed 100 copies of the book to relevant personnel. Until its dissolution in 1947, the Department of the Interior included the Police Department and had a great deal of authority. The Health and Welfare Ministry became independent from the Department of the Interior in 1938. Therefore, mental institutions were under the supervision of the police force for many years. At the time, an important task for police officers was to search for infectious disease patients and to seclude and restrain them. Thus, home custody for mental patients was also supervised under the direction of the Police Department. This book is a record of an external investigation performed by psychiatrists on home custody supervised by the police. When investigating the conditions, one of the psychiatrists obtained a copy of "Documents for mental patients under confinement" at the local police station. The contents of these documents included records of hearings by the police, as well as applications for confinement submitted by family members, as well as detailed specifications and drawings of the confinement room. With a local photographer, they traveled deep into the mountains to investigate the conditions under which mental patients were living. The book

  15. Satellites

    SciTech Connect

    Burns, J.A.; Matthews, M.S.

    1986-01-01

    The present work is based on a conference: Natural Satellites, Colloquium 77 of the IAU, held at Cornell University from July 5 to 9, 1983. Attention is given to the background and origins of satellites, protosatellite swarms, the tectonics of icy satellites, the physical characteristics of satellite surfaces, and the interactions of planetary magnetospheres with icy satellite surfaces. Other topics include the surface composition of natural satellites, the cratering of planetary satellites, the moon, Io, and Europa. Consideration is also given to Ganymede and Callisto, the satellites of Saturn, small satellites, satellites of Uranus and Neptune, and the Pluto-Charon system.

  16. Combined Use of CO and CO2 Satellite Observations

    NASA Astrophysics Data System (ADS)

    Krol, M. C.; Basu, S.; Guerlet, S.; Clerbaux, C.; Houweling, S.

    2013-12-01

    CO2 satellite observations from GOSAT may inform about biosphere-atmosphere exchange of CO2. Here we address the specific question whether we can separate CO2 contributions from biomass burning and the respiration/assimilation exchange. To this end, we first employ IASI CO observations to constrain the biomass burning process. We then translate the CO emissions into CO2 biomass burning emissions using emission factors. Finally, we determine to CO2 exchange flux using the biomass burning CO2 emissions as a prior. All source inversions are done using the TM5-4DVAR system, which allows a 1x1 degree resolution zoom over regions of interest. We focus on regions that experienced drought and fire-related CO anomalies, such as the widespread drought around Moscow in 2010. We show that fire CO2 emissions can only partially explain the observed CO2 anomalies. The remaining anomaly are therefore attributed to reduced net CO2 uptake by the biosphere.

  17. EUV observation from the Earth-orbiting satellite, EXCEED

    NASA Astrophysics Data System (ADS)

    Yoshioka, K.; Murakami, G.; Yoshikawa, I.; Ueno, M.; Uemizu, K.; Yamazaki, A.

    2010-01-01

    An Earth-orbiting small satellite “EXtreme ultraviolet spectrosCope for ExosphEric Dynamics” (EXCEED) which will be launched in 2012 is under development. The mission will carry out spectroscopic and imaging observation of EUV (Extreme Ultraviolet: 60-145 nm) emissions from tenuous plasmas around the planets (Venus, Mars, Mercury, and Jupiter). It is essential for EUV observation to put on an observing site outside the Earth’s atmosphere to avoid the absorption. It is also essential that the detection efficiency must be very high in order to catch the faint signals from those targets. In this mission, we employ cesium iodide coated microchannel plate as a 2 dimensional photon counting devise which shows 1.5-50 times higher quantum detection efficiency comparing with the bared one. We coat the surface of the grating and entrance mirror with silicon carbides by the chemical vapor deposition method in order to archive the high diffraction efficiency and reflectivity. The whole spectrometer is shielded by the 2 mm thick stainless steel to prevent the contamination caused by the high energy electrons from the inner radiation belt. In this paper, we will introduce the mission overview, its instrument, and their performance.

  18. Parameterization of oceanic whitecap fraction based on satellite observations

    NASA Astrophysics Data System (ADS)

    Albert, M. F. M. A.; Anguelova, M. D.; Manders, A. M. M.; Schaap, M.; de Leeuw, G.

    2015-08-01

    In this study the utility of satellite-based whitecap fraction (W) values for the prediction of sea spray aerosol (SSA) emission rates is explored. More specifically, the study is aimed at improving the accuracy of the sea spray source function (SSSF) derived by using the whitecap method through the reduction of the uncertainties in the parameterization of W by better accounting for its natural variability. The starting point is a dataset containing W data, together with matching environmental and statistical data, for 2006. Whitecap fraction W was estimated from observations of the ocean surface brightness temperature TB by satellite-borne radiometers at two frequencies (10 and 37 GHz). A global scale assessment of the data set to evaluate the wind speed dependence of W revealed a quadratic correlation between W and U10, as well as a relatively larger spread in the 37 GHz data set. The latter could be attributed to secondary factors affecting W in addition to U10. To better visualize these secondary factors, a regional scale assessment over different seasons was performed. This assessment indicates that the influence of secondary factors on W is for the largest part imbedded in the exponent of the wind speed dependence. Hence no further improvement can be expected by looking at effects of other factors on the variation in W explicitly. From the regional analysis, a new globally applicable quadratic W(U10) parameterization was derived. An intrinsic correlation between W and U10 that could have been introduced while estimating W from TB was determined, evaluated and presumed to lie within the error margins of the newly derived W(U10) parameterization. The satellite-based parameterization was compared to parameterizations from other studies and was applied in a SSSF to estimate the global SSA emission rate. The thus obtained SSA production for 2006 of 4.1 × 1012 kg is within previously reported estimates. While recent studies that account for parameters other than U

  19. Wave energy resource assessment based on satellite observations around Indonesia

    NASA Astrophysics Data System (ADS)

    Ribal, Agustinus; Zieger, Stefan

    2016-06-01

    A preliminary assessment of wave energy resource around Indonesian's ocean has been carried out by means of analyzing satellite observations. The wave energy flux or wave power can be approximated using parameterized sea states. Wave power scales with significant wave height, characteristic wave period and water depth. In this approach, the significant wave heights were obtained from ENVISAT (Environmental Satellite) data which have been calibrated. However, as the characteristic wave period is rarely specified and therefore must be estimated from other variables when information about the wave spectra is unknown. Here, the characteristic wave period was calculated with an empirical model that utilizes altimeter estimates of wave height and backscatter coefficient originally proposed. For the Indonesian region, wave power energy is calculated over two periods of one year each and was compared with the results from global hindcast carried out with a recent release of wave model WAVEWATCH III. We found that, the most promising wave power energy regions around the Indonesian archipelago are located in the south of Java island and the south west of Sumatera island. In these locations, about 20 - 30 kW/m (90th percentile: 30-50 kW/m, 99th percentile: 40-60 kW/m) wave power energy on average has been found around south of Java island during 2010. Similar results have been found during 2011 at the same locations. Some small areas which are located around north of Irian Jaya (West Papua) are also very promising and need further investigation to determine its capacity as a wave energy resource.

  20. Satellite microwave observations of soil moisture variations. [by the microwave radiometer on the Nimbus 5 satellite

    NASA Technical Reports Server (NTRS)

    Schmugge, T. J.; Rango, A.; Neff, R.

    1975-01-01

    The electrically scanning microwave radiometer (ESMR) on the Nimbus 5 satellite was used to observe microwave emissions from vegetated and soil surfaces over an Illinois-Indiana study area, the Mississippi Valley, and the Great Salt Lake Desert in Utah. Analysis of microwave brightness temperatures (T sub B) and antecedent rainfall over these areas provided a way to monitor variations of near-surface soil moisture. Because vegetation absorbs microwave emission from the soil at the 1.55 cm wavelength of ESMR, relative soil moisture measurements can only be obtained over bare or sparsely vegetated soil. In general T sub B increased during rainfree periods as evaporation of water and drying of the surface soil occurs, and drops in T sub B are experienced after significant rainfall events wet the soil. Microwave observations from space are limited to coarse resolutions (10-25 km), but it may be possible in regions with sparse vegetation cover to estimate soil moisture conditions on a watershed or agricultural district basis, particularly since daily observations can be obtained.

  1. Whistler emissions in the magnetosphere - satellite observations and numerical modeling

    NASA Astrophysics Data System (ADS)

    Chum, J.; Jiricek, F.; Shklyar, D. R.

    The investigation of ionospheric and magnetospheric wave phenomena related to lightning strokes began from classical research by Eckersley (Nature, Lond., 135, 104, 1935) and Storey (Phil. Trans. Roy. Soc. Lond., A246, 908, 113-141, 1953) among others, and it has continued up to the present. VLF spectrograms from the MAGION 4 and MAGION 5 satellites contain most of the known types of VLF emissions, as well as some new ones not discussed previously. A partial list of the observed emissions involving nonducted propagation includes: magnetospherically reflected (MR) whistlers (and their subclass, Nu whistlers) predicted by Kimura (Radio Sci., 1, 3, 269-283, 1966) and then found by Smith and Angerami in the spectrograms of wave data from OGO 1 and 3 (J. Geophys. Res., 73, 1, 1-20, 1968); lower hybrid resonance (LHR) noise bands; LHR whistlers and LHR spherics; and oblique noise bands above the local LHR frequency. Recently, a new line of investigation was initiated by numerical modeling of VLF spectrograms of nonducted emissions caused by lightning. For such emissions, as observed by a satellite in the magnetosphere, the spectrograms depend on several factors: the properties of the source, the geomagnetic field structure and the cold plasma distribution which jointly influence the wave propagation, and the resonant interactions of the waves with energetic particles. Therefore, numerical modeling of spectrograms and comparing them with real ones may serve as an indirect tool for investigating the factors mentioned above and any other processes that affect the spectrograms. This tool is especially effective when the source of the emission is known, in particular with lightning-induced emissions. The main features of our numerical method for modeling spectrograms include: a) representation of the wave field as the sum of wave packets treatable by geometrical optics; b) construction of a frequency-time plot based on the notion of a group front; c) calculation of the

  2. Lunar Crustal Modeling of Mare Orientale from Clementine Satellite Observations

    NASA Astrophysics Data System (ADS)

    von Frese, R. R. B.; Tan, L.; Potts, L. V.; Merry, C. J.; Bossler, J. D.

    1996-03-01

    Clementine satellite gravity and altimetry observations were analyzed in lunar spherical coordinates for density variations that may be related to the crustal features and evolution of Mare Orientale. The analysis considered 2-degree gridded free-air gravity anomaly and LIDAR topographic estimates for a 68-degree by 68-degree region of the moon centered roughly on Mare Orientale. At this scale of coverage, the gravity anomalies appear to be dominated almost completely by crustal density variations related to surface topography, crustal isostasy, mantle topography, and meteorite impact. The topography of the study region includes over 11 km of relief, the gravity effect of which we modeled in lunar spherical coordinates by Gauss-Legendre quadrature integration assuming a topographic density of 2.8 g/cc. We observed substantial positive and negative correlations between the free-air and topographic gravity anomalies that seriously limit the utility of simple Bouguer gravity anomalies for lunar subsurface studies. Using the wavenumber correlation spectrum between the free-air and topographic gravity anomalies, we designed correlation filters to extract the the correlative anomalies in the two data sets.

  3. Satellite Observations of Antarctic Sea Ice Thickness and Volume

    NASA Technical Reports Server (NTRS)

    Kurtz, Nathan; Markus, Thorsten

    2012-01-01

    We utilize satellite laser altimetry data from ICESat combined with passive microwave measurements to analyze basin-wide changes in Antarctic sea ice thickness and volume over a 5 year period from 2003-2008. Sea ice thickness exhibits a small negative trend while area increases in the summer and fall balanced losses in thickness leading to small overall volume changes. Using a five year time-series, we show that only small ice thickness changes of less than -0.03 m/yr and volume changes of -266 cu km/yr and 160 cu km/yr occurred for the spring and summer periods, respectively. The calculated thickness and volume trends are small compared to the observational time period and interannual variability which masks the determination of long-term trend or cyclical variability in the sea ice cover. These results are in stark contrast to the much greater observed losses in Arctic sea ice volume and illustrate the different hemispheric changes of the polar sea ice covers in recent years.

  4. Monitoring of Observation Errors from Satellite Ozone Instruments in Assimilation

    NASA Technical Reports Server (NTRS)

    Stajner, Ivanka; Winslow, Nathan; Rood, Richard B.; Pawson, Steven

    2002-01-01

    Ozone distributions derived from the Solar Backscatter UltraViolet/2 (SBUV/2) instruments and the Earth Probe Total Ozone Mapping Spectrometer (EP TOMS) have been assimilated in near-real time at the NASA/Goddard Data Assimilation Office since January 2000. Observed-minus-forecast (O-F) residuals are the differences between the incoming ozone data and the co-located short-term model forecast. They are routinely produced and monitored in the assimilation process. Using examples from the NOAA-14 and NOAA-16 SBUV/2 and the EP-TOMS instruments, it is demonstrated that the monitoring of time series of O-F residual statistics is an effective method of identifying time-dependent changes in the observation-error characteristics of ozone. In addition, the data assimilation system was used to assist the validation of updated calibration coefficients for the NOAA-14 SBUV/2 instrument. This assimilation-based monitoring work will be extended to ozone data from instruments on new satellites: Envisat EOS, Aqua, and EOS Aura.

  5. Time Resolved Atmospheric Carbon Satellite Observations from Geostationary Orbit

    NASA Astrophysics Data System (ADS)

    Edwards, David; Worden, Helen

    This presentation describes proposed satellite carbon measurements from CHRONOS (Commercially Hosted spectroRadiometer Observations and New Opportunities for Science). The primary goal of this mission is to measure the atmospheric pollutants carbon monoxide (CO) and methane (CH4) from geostationary orbit, with hourly observations of North America at high spatial resolution. Carbon monoxide is produced by combustion processes such as urban activity and wildfires, and serves as a proxy for other combustion pollutants that are not easily measured. Both CO and CH4 are chemical precursors of tropospheric ozone pollution. Methane has diverse anthropogenic sources ranging from fossil fuel production, animal husbandry, agriculture and waste management. The impact of gas exploration in the Western States of the USA and oil extraction from the Canadian tar sands will be particular foci of the mission, as will the poorly-quantified natural CH4 emissions from wetlands and thawing permafrost. In addition to characterizing pollutant sources, improved understanding of the domestic CH4 budget is a priority for policy decisions related to short-lived climate forcers. A primary motivation for targeting CO is its value as a tracer of atmospheric pollution. The CHRONOS measurements will provide insight into local and long-range transport across the North American continent, as well as the processes governing the entrainment and venting of pollution in and out of the planetary boundary layer. As a result of significantly improved characterization of diurnal changes in atmospheric composition, CHRONOS observations will find direct societal applications for air quality regulation and forecasting. We present a quantification of this expected improvement in the prediction of near-surface concentrations when CHRONOS measurements are used in Observation System Simulation Experiments (OSSEs). If CHRONOS and the planned NASA Earth Venture TEMPO (Tropospheric Emissions: Monitoring of Pollution

  6. ECC Ozonesonde Reliability, Observations, and Comparisons with Satellite Ozone Instruments

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.; Northam, E. T.; Ross, E. D.; Schauer, A. G.; Gerlach, John C. (Technical Monitor)

    2001-01-01

    Electrochemical Concentration Cell (ECC) ozone instruments depend on the quality of care exercised in their pre-flight preparation. The ozone-measuring project conducted at Goddard Space Flight Center's Wallops Flight Facility uses a number of mechanisms designed to inspect the ECC for anomalies that may interfere with the reception of valid ozone profiles. Complete electronic testing of the instrument, individually and when coupled to its radiosonde has led to exceptional monitoring of ozone for detecting long-term atmospheric changes. A number of factors are considered when preparing an ECC instrument for flight. These basically are specific calibrations of pump efficiency, volumetric flow rate, temperature of the air entering the pump, and background current. The concentration of the potassium iodide solution is also important. Wallops is the only site using a UV photometer (Dasibi) to compare ECC ozone output at various concentrations of ozone that allows adjustment to be made to offsets that may appear in the balloon-borne instrument prior to release. All of the above procedures allow identification of potential problems before release of the ECC instrument. Procedures followed at Wallops also are employed in Brazil, and Ascension Island where NASA has cooperative agreements in place to obtain ozonesondes data. All ECC instruments are prepared 3-4 weeks prior to the day of observation. We will briefly describe the instrumental tests employed. These tests have included simultaneous dual observations to compare the effect of different solution concentrations, comparison of sensors of different manufacturers, and comparisons with surface- and space-based instrumentation such as the Dobson Spectrophotometer and satellites. Vertical profiles of ozone from Arctic, mid-latitudes, and Antarctica will be discussed. Although not unusual, the data reveals ozone structure that correlate well with typical atmospheric temperatures and possibly relative humidity. Finally

  7. A Critical Review of the Time Series of Total Solar Irradiance Satellite Observations

    NASA Astrophysics Data System (ADS)

    Willson, R. C.

    2006-12-01

    PMOD composite approach uses a different subset of the satellite TSI database, the ERBS/ERBE ACRIM gap ratio and modifies published Nimbus7/ERB and ACRIM1 results, based on degradation assumptions derived from linear regression TSI proxy models. There are a number of differences between the ACRIM and PMOD composites but the most important is the trend during solar cycles 21 - 23. The absence of a trend in the PMOD composite and any composite based on the ERBS/ERBE ACRIM gap ratio has been shown to be an artifact of uncorrected degradation of ERBE results during the gap. The ERBS/ERBE database was significantly affected by uncorrected degradation throughout its observational lifetime and provides a less precise ACRIM gap ratio than the Nimbus7/ERB results. TSI proxy models are not competitive in precision or accuracy with even the lowest quality satellite TSI observations. Their use in constructing the PMOD composite convolutes the relatively high uncertainty of the model with the observational data and is less likely to represent the best interpretation of the extant TSI observational database. The PMOD composite used modified published Nimbus7/ERB and ACRIM1 data. The ACRIM1 modifications were based on erroneous assumptions regarding degradation of the experiment. No effort was made to verify these assumptions using actual ACRIM1 data. The resulting PMOD composite provides better agreement with TSI proxy model predictions during the maximum of solar cycle 21 but does not provide the best representation of the actual TSI. The ACRIM TSI composite time series is the most accurate representation of the extant TSI satellite measurement database. It doesn't rely on imprecise proxy modeling or modifications of published observational results.

  8. Observational capabilities of solar satellite "Coronas-Photon"

    NASA Astrophysics Data System (ADS)

    Kotov, Yu.

    Coronas-Photon mission is the third satellite of the Russian Coronas program on solar activity observation The main goal of the Coronas-Photon is the study of solar hard electromagnetic radiation in the wide energy range from UV up to high energy gamma-radiation sim 2000MeV Scientific payload for solar radiation observation consists of three type of instruments 1 monitors Natalya-2M Konus-RF RT-2 Penguin-M BRM Phoka Sphin-X Sokol for spectral and timing measurements of full solar disk radiation with timing in flare burst mode up to one msec Instruments Natalya-2M Konus-RF RT-2 will cover the wide energy range of hard X-rays and soft Gamma rays 15keV to 2000MeV and will together constitute the largest area detectors ever used for solar observations Detectors of gamma-ray monitors are based on structured inorganic scintillators with energy resolution sim 5 for nuclear gamma-line band to 35 for GeV-band PSD analysis is used for gamma neutron separation for solar neutron registration T 30MeV Penguin-M has capability to measure linear polarization of hard X-rays using azimuth are measured by Compton scattering asymmetry in case of polarization of an incident flux For X-ray and EUV monitors the scintillation phoswich detectors gas proportional counter CZT assembly and Filter-covered Si-diodes are used 2 Telescope-spectrometer TESIS for imaging solar spectroscopy in X-rays with angular resolution up to 1 in three spectral lines and RT-2 CZT assembly of CZT

  9. Analyses of Global Monthly Precipitation Using Gauge Observations, Satellite Estimates, and Numerical Model Predictions.

    NASA Astrophysics Data System (ADS)

    Xie, Pingping; Arkin, Phillip A.

    1996-04-01

    An algorithm is developed to construct global gridded fields of monthly precipitation by merging estimates from five sources of information with different characteristics, including gauge-based monthly analyses from the Global Precipitation Climatology Centre, three types of satellite estimates [the infrared-based GOES Precipitation Index, the microwave (MW) scattering-based Grody, and the MW emission-based Chang estimates], and predictions produced by the operational forecast model of the European Centre for Medium-Range Weather Forecasts. A two-step strategy is used to: 1) reduce the random error found in the individual sources and 2) reduce the bias of the combined analysis. First, the three satellite-based estimates and the model predictions are combined linearly based on a maximum likelihood estimate, in which the weighting coefficients are inversely proportional to the squares of the individual random errors determined by comparison with gauge observations and subjective assumptions. This combined analysis is then blended with an analysis based on gauge observations using a method that presumes that the bias of the gauge-based field is small where sufficient gauges are available and that the gradient of the precipitation field is best represented by the combination of satellite estimates and model predictions elsewhere. The algorithm is applied to produce monthly precipitation analyses for an 18-month period from July 1987 to December 1988. Results showed substantial improvements of the merged analysis relative to the individual sources in describing the global precipitation field. The large-scale spatial patterns, both in the Tropics and the extratropics, are well represented with reasonable amplitudes. Both the random error and the bias have been reduced compared to the individual data sources, and the merged analysis appears to be of reasonable quality everywhere. However, the actual quality of the merged analysis depends strongly on our uncertain and

  10. Making Data Visible: Satellite Observations of Arctic Change (SOAC)

    NASA Astrophysics Data System (ADS)

    Beitler, J.; Tanner, S.; Barrett, A. P.; Savoie, M. H.; Wilcox, H.; Hoyer, T.; Beam, K.

    2014-12-01

    A new Web site, Satellite Observations of Arctic Change (SOAC, http://nsidc.org/soac), was developed to open up NASA Earth science data that show changes taking place in the Arctic over time to a broader range of users. The site was designed to be used by decision makers, teachers, non-specialist scientists, and the motivated public without the need for technical tools or expertise in manipulating data. The data are displayed on interactive maps, allowing users to explore how and where conditions in the Arctic have changed from the 1970s to the present. Users may animate a time series, zoom in or out, and view a bar graph of anomalies over time. Supporting pages provide brief scientific discussion and background to help users understand the data and the significance of the changes. Links to the source data and documentation are also included. Initial data products for SOAC include anomalies associated with near-surface air temperature; water vapor; sea ice concentration; snow cover; and several others. The potential for use and for inclusion of more data will be discussed.

  11. First Satellite Observations of Lower Tropospheric Ammonia and Methanol

    NASA Technical Reports Server (NTRS)

    Beer, Reinhard; Shephard, Mark W.; Kulawik, Susan S.; Clough, Shepard A.; Eldering, Annmarie; Bowman, Kevin W.; Sander, Stanley P.; Fisher, Brendan M.; Payne, Vivienne H.; Luo, Mingzhao; Osterman, Gregory B.; Worden, John R.

    2008-01-01

    The Tropospheric Emission Spectrometer (TES) on the EOS Aura satellite makes global measurements of infrared radiances which are used to derive profiles of species such as O3, CO, H2O, HDO and CH4 as routine standard products. In addition, TES has a variety of special modes that provide denser spatial mapping over a limited geographical area. A continuous-coverage mode (called ''transect'', about 460 km long) has now been used to detect additional molecules indicative of regional air pollution. On 10 July 2007 at about 05:37 UTC (13:24 LMST) TES conducted such a transect observation over the Beijing area in northeast China. Examination of the residual spectral radiances following the retrieval of the TES standard products revealed surprisingly strong features attributable to enhanced concentrations of ammonia (NH3) and methanol (CH3OH), well above the normal background levels. This is the first time that these molecules have been detected in space-based nadir viewing measurements that penetrate into the lower atmosphere.

  12. Remote sensing satellite formation for bistatic synthetic aperture radar observation

    NASA Astrophysics Data System (ADS)

    D'Errico, Marco; Moccia, Antonio

    2001-12-01

    In recent years the Italian Space Agency has been proceeding to the definition and launch of small missions. In this ambit, the BISSAT mission was proposed and selected along with five other missions for a competitive Phase A study. BISSAT mission concept consists in flying a passive SAR on board a small satellite, which observes the area illuminated by an active SAR, operating on an already existing large platform. Several scientific applications of bistatic measurements can be envisaged: improvement of image classification and pattern recognition, derivation of medium-resolution digital elevation models, velocity measurements, measurements of sea-wave spectra. BISSAT payload is developed on the basis of the X-band SAR of the COSMO/SkyMed mission, while BISSAT bus is based on an upgrade of MITA. Orbit design has been performed, leading to the same orbit parameters apart from the ascending node right ascension (5.24 degree(s) shift) and the time of the passage on the ascending node (1.17s shift). A minimum distance at the passage of the orbit crossing point of about 42 km (5.7s) is computed. To maintain adequate swath overlap along the orbit, attitude maneuver or antenna electronic steering must be envisaged and traded-off taking into account radar performance and cost of hardware upgrade.

  13. Sensitivity of Northern Hemispheric Tropospheric Ozone To Anthropogenic Emissions as Observed by Satellite Observations

    NASA Astrophysics Data System (ADS)

    Jiang, Z.; Worden, J. R.; Payne, V.; Bowman, K. W.; Kuai, L.; Jones, D. B. A.; Henze, D. K.

    2015-12-01

    Atmospheric composition is rapidly changing in response to changes in industrialization, land-use, and climate. Tropospheric ozone is at the nexus of atmospheric chemistry, air-quality, and climate as it is not only the third most important greenhouse gas and a primary air pollutant, but also affects carbon dioxide by damaging plants and the lifetime of atmospheric methane by influencing the oxidative capacity of the atmosphere. Observed trends in free-tropospheric ozone as observed by ozone-sondes and more recently by satellite measurements from the Aura TES and IASI instruments do not agree with models that are driven by observed changes in ozone pre-cursor emissions. As a consequence, estimates of ozone radiative forcing and the future trajectory of tropospheric ozone concentrations are highly uncertain. In this study, we explore the use of satellite observations of ozone and its pre-cursors for constraining the sensitivity of Northern hemispheric tropospheric ozone to anthropogenic emissions. New measurements of peroxyacetyl nitrate (PAN) from the Aura TES instrument suggest that one explanation for the model/data mismatch in trends is reduced ventilation of reactive nitrogen into the free-troposphere over Asia. Ultimately, continued well validated observation of ozone and its pre-cursors from IASI, AIRS, CRIS, and Trop-OMI will be needed to solve this critical scientific question.

  14. NASDA's earth observation satellite data archive policy for the earth observation data and information system (EOIS)

    NASA Technical Reports Server (NTRS)

    Sobue, Shin-ichi; Yoshida, Fumiyoshi; Ochiai, Osamu

    1996-01-01

    NASDA's new Advanced Earth Observing Satellite (ADEOS) is scheduled for launch in August, 1996. ADEOS carries 8 sensors to observe earth environmental phenomena and sends their data to NASDA, NASA, and other foreign ground stations around the world. The downlink data bit rate for ADEOS is 126 MB/s and the total volume of data is about 100 GB per day. To archive and manage such a large quantity of data with high reliability and easy accessibility it was necessary to develop a new mass storage system with a catalogue information database using advanced database management technology. The data will be archived and maintained in the Master Data Storage Subsystem (MDSS) which is one subsystem in NASDA's new Earth Observation data and Information System (EOIS). The MDSS is based on a SONY ID1 digital tape robotics system. This paper provides an overview of the EOIS system, with a focus on the Master Data Storage Subsystem and the NASDA Earth Observation Center (EOC) archive policy for earth observation satellite data.

  15. Wind-driven marine phytoplank blooms: Satellite observation and analysis

    NASA Astrophysics Data System (ADS)

    Tang, DanLing

    2016-07-01

    Algal bloom is defined as a rapid increase or accumulation in biomass in an aquatic system. It not only can increase the primary production but also could result in negative ecological consequence, e.g.,Harmful Algal Blooms (HABs). According to the classic theory for the formation of algal blooms "critical depth" and "eutrophication", oligotrophic sea area is usually difficult to form a large area of algal blooms, and actuallythe traditional observation is only sporadic capture to the existence of algal blooms.Taking full advantage of multiple data of satellite remote sensing , this study introduces "Wind-driven algal blooms in open oceans: observation and mechanisms" It explained except classic coastal Ekman transport, the wind through a variety of mechanisms affecting the formation of algal blooms. Proposed a conceptual model of "Strong wind -upwelling-nutrient-phytoplankton blooms" in Western South China Sea (SCS) to assess role of wind-induced advection transport in phytoplankton bloom formation. It illustrates the nutrient resources that support long-term offshore phytoplankton blooms in the western SCS; (2)Proposal of the theory that "typhoons cause vertical mixing, induce phytoplankton blooms", and quantify their important contribution to marine primary production; Proposal a new ecological index for typhoon. Proposed remote sensing inversion models. (3)Finding of the spatial and temporaldistributions pattern of harmful algal bloom (HAB)and species variations of HAB in the South Yellow Sea and East China Sea, and in the Pearl River estuary, and their oceanic dynamic mechanisms related with monsoon; The project developed new techniques and generated new knowledge, which significantly improved understanding of the formation mechanisms of algal blooms. The proposed "wind-pump" mechanism integrates theoretical system combined "ocean dynamics, development of algal blooms, and impact on primary production", which will benefit fisheries management. These

  16. An observational philosophy for GEOS-C satellite altimetry

    NASA Technical Reports Server (NTRS)

    Weiffenbach, G. C.

    1972-01-01

    The parameters necessary for obtaining a 10 cm accuracy for GEOS-C satellite altimetry are outlined. These data include oceanographic parameters, instrument calibration, pulse propagation, sea surface effects, and optimum design.

  17. MISR Satellite Observations of Aerosol Types Affecting Human Health

    NASA Astrophysics Data System (ADS)

    Kalashnikova, O. V.; Franklin, M.; Garay, M. J.; Diner, D. J.

    2015-12-01

    Ground-based observations of pollutants and concentrations of particulate matter (PM), that includes small particles designated PM2.5 and dust-dominated PM10, are the gold standard in studies of environmental impacts on human health. However, because monitoring stations are costly, they typically provide only limited spatial coverage, especially in rural and remote areas. We will demonstrate how data from the Multi-angle Imaging SpectroRadiometer (MISR) instrument that has been flying on NASA's Terra Earth Observing System satellite since early 2000 can be used to provide estimates of surface PM types. The current MISR operational aerosol retrieval uses a combination of multi-spectral and multi-angle data to retrieve aerosol optical depth (AOD) and particle property information (including dust AOD) globally at 17.6 km spatial resolution. Using the same algorithm with data collected in all 36-channels at 275 m resolution (Local Mode), which is available over greater Los Angeles area, and also was activated during 2013 DISCOVER-AQ California field campaign, high-resolution 4.4 km aerosol retrievals were performed in addition to the standard 17.6 km retrievals. The 4.4 km spatial resolution of the PM information data is fine enough to be able to resolve local differences in PM loading that may be important for understanding regional health effects of pollution in the region. In particular, we demonstrate that MISR high-resolution AOD retrievals are in better agreement with ground-based aerosol observations and reveal more details about the aerosol spatial variability compared to the MISR standard 17.6 km product. Then we will discuss techniques and show examples of the application of high-resolution MISR data to provide estimates of surface PM for the greater Los Angeles area in 2008 and for California San Joaquin Valley during the 2013 DISCOVER-AQ field campaign. Finally, we will discuss future NASA instruments that will provide new information allowing for better

  18. Observations of land-atmosphere interactions using satellite data

    NASA Astrophysics Data System (ADS)

    Green, Julia; Gentine, Pierre; Konings, Alexandra; Alemohammad, Hamed; Kolassa, Jana

    2016-04-01

    Observations of land-atmosphere interactions using satellite data Julia Green (1), Pierre Gentine (1), Alexandra Konings (1,2), Seyed Hamed Alemohammad (3), Jana Kolassa (4) (1) Columbia University, Earth and Environmental Engineering, NY, NY, USA, (2) Stanford University, Environmental Earth System Science, Stanford, CA, USA, (3) Massachusetts Institute of Technology, Civil and Environmental Engineering, Cambridge, MA, USA, (4) National Aeronautics and Space Administration/Goddard Space Flight Center, Greenbelt, MD, USA. Previous studies of global land-atmosphere hotspots have often relied solely on data from global models with the consequence that they are sensitive to model error. On the other hand, by only analyzing observations, it can be difficult to distinguish causality from mere correlation. In this study, we present a general framework for investigating land-atmosphere interactions using Granger Causality analysis applied to remote sensing data. Based on the near linear relationship between chlorophyll sun induced fluorescence (SIF) and photosynthesis (and thus its relationship with transpiration), we use the GOME-2 fluorescence direct measurements to quantify the surface fluxes between the land and atmosphere. By using SIF data to represent the flux, we bypass the need to use soil moisture data from FLUXNET (limited spatially and temporally) or remote sensing (limited by spatial resolution, canopy interference, measurement depth, and radio frequency interference) thus eliminating additional uncertainty. The Granger Causality analysis allows for the determination of the strength of the two-way causal relationship between SIF and several climatic variables: precipitation, radiation and temperature. We determine that warm regions transitioning from water to energy limitation exhibit strong feedbacks between the land surface and atmosphere due to their high sensitivity to climate and weather variability. Tropical rainforest regions show low magnitudes of

  19. Satellite observations of air-sea interaction over the Kuroshio

    NASA Astrophysics Data System (ADS)

    Xie, S.; Nonaka, M.; Hafner, J.; Liu, W. T.

    2002-12-01

    Satellite microwave measurements are analyzed, revealing robust co-variability in sea surface temperature (SST) and wind speed over the Kuroshio and its Extension (KE). Ocean hydrodynamic instabilities cause the KE to meander and result into large SST variations. Increased (reduced) wind speeds are found to be associated with warm (cold) SST anomalies. This positive SST-wind correlation in KE is confirmed by in-situ buoy measurements and is consistent with a vertical shear adjustment mechanism. Namely, an increase in SST reduces the static stability of the near-surface atmosphere, intensifying the vertical turbulence mixing and bringing fast-moving air from aloft to the sea surface. South of Japan, the Kuroshio is known to vary between nearshore and offshore paths. Both paths seem semi-permanent and can persist months to years. As the Kuroshio shifts its path, coherent wind changes are detected. In particular, winds are high south of Tokyo when the Kuroshio takes the nearshore path while they are greatly reduced when this warm current leaves the coast in the offshore path. Further upstream in the East China Sea, on the warmer flank of the Kuroshio Front, there are a zone of high wind speed and a band of raining cloud due to the region's unstable atmospheric stratification near the surface. Surface wind convergence is roughly collocated with the Kuroshio Current. By increasing the baroclinicity and condensational heating, the Kuroshio Front aids the growth of the so-called Taiwan cyclone, an important winter weather phenomenon for Japan. The positive SST-wind correlation over the strong Kuroshio Current and its extension is opposite to the negative one often observed in regions of weak currents such as south of the Aleutian low that is considered to be indicative of atmosphere-to-ocean forcing.

  20. Observation of Wetland Dynamics with Global Navigation Satellite Signals Reflectometry

    NASA Astrophysics Data System (ADS)

    Zuffada, C.; Shah, R.; Nghiem, S. V.; Cardellach, E.; Chew, C. C.

    2015-12-01

    Wetland dynamics is crucial to changes in both atmospheric methane and terrestrial water storage. The Intergovernmental Panel on Climate Change's Fifth Assessment Report (IPCC AR5) highlights the role of wetlands as a key driver of methane (CH4) emission, which is more than one order of magnitude stronger than carbon dioxide as a greenhouse gas in the centennial time scale. Among the multitude of methane emission sources (hydrates, livestock, rice cultivation, freshwaters, landfills and waste, fossil fuels, biomass burning, termites, geological sources, and soil oxidation), wetlands constitute the largest contributor with the widest uncertainty range of 177-284 Tg(CH4) yr-1 according to the IPCC estimate. Wetlands are highly susceptible to climate change that might lead to wetland collapse. Such wetland destruction would decrease the terrestrial water storage capacity and thus contribute to sea level rise, consequently exacerbating coastal flooding problems. For both methane change and water storage change, wetland dynamics is a crucial factor with the largest uncertainty. Nevertheless, a complete and consistent map of global wetlands still needs to be obtained as the Ramsar Convention calls for a wetlands inventory and impact assessment. We develop a new method for observations of wetland change using Global Navigation Satellite Signals Reflectometry (GNSS-R) signatures for global wetland mapping in synergy with the existing capability, not only as a static inventory but also as a temporal dataset, to advance the capability for monitoring the dynamics of wetland extent relevant to addressing the science issues of CH4 emission change and terrestrial water storage change. We will demonstrate the capability of the new GNSS-R method over a rice field in the Ebro Delta wetland in Spain.

  1. Retrieval of Aerosol Absorption Properties from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Torres, Omar; Bhartia, Pawan K.; Jethva, H.; Ahn, Chang-Woo

    2012-01-01

    The Angstrom Absorption Exponent (AAE) is a parameter commonly used to characterize the wavelength-dependence of aerosol absorption optical depth (AAOD). It is closely related to aerosol composition. Black carbon (BC) containing aerosols yield AAE values near unity whereas Organic carbon (OC) aerosol particles are associated with values larger than 2. Even larger AAE values have been reported for desert dust aerosol particles. Knowledge of spectral AAOD is necessary for the calculation of direct radiative forcing effect of aerosols and for inferring aerosol composition. We have developed a satellitebased method of determining the spectral AAOD of absorbing aerosols. The technique uses multi-spectral measurements of upwelling radiation from scenes where absorbing aerosols lie above clouds as indicated by the UV Aerosol Index. For those conditions, the satellite measurement can be explained, using an approximations of Beer's Law (BL), as the upwelling reflectance at the cloud top attenuated by the absorption effects of the overlying aerosol layer. The upwelling reflectance at the cloud-top in an aerosol-free atmospheric column is mainly a function of cloud optical depth (COD). In the proposed method of AAE derivation, the first step is determining COD which is retrieved using a previously developed color-ratio based approach. In the second step, corrections for molecular scattering effects are applied to both the observed ad the calculated cloud reflectance terms, and the spectral AAOD is then derived by an inversion of the BL approximation. The proposed technique will be discussed in detail and application results making use of OMI multi-spectral measurements in the UV-Vis. will be presented.

  2. Lunar occultation of Saturn. IV - Astrometric results from observations of the satellites

    NASA Technical Reports Server (NTRS)

    Dunham, D. W.; Elliot, J. L.

    1978-01-01

    The method of determining local lunar limb slopes, and the consequent time scale needed for diameter studies, from accurate occultation timings at two nearby telescopes is described. Results for photoelectric observations made at Mauna Kea Observatory during the occultation of Saturn's satellites on March 30, 1974, are discussed. Analysis of all observations of occultations of Saturn's satellites during 1974 indicates possible errors in the ephemerides of Saturn and its satellites.

  3. Satellite observations of transient radio impulses from thunderstorms

    SciTech Connect

    Argo, P.E.; Kirkland, M.; Jacobson, A.; Massey, R.; Suszynsky, D.; Eack, K.; Fitzgerald, T.J.; Smith, D.

    1999-06-01

    Transient radio emissions from thunderstorms detected by satellites were first reported in 1995. The nature and source of these emissions remained a mystery until the launch of the FORTE satellite in 1997. FORTE, with its more sophisticated triggering and larger memory capacity showed that these emissions were connected to major thunderstorm systems. The analysis reported here, connecting FORTE RF events with ground based lightning location data from the National Lightning Detection Network (NLDN), shows that localized regions within thunderstorms are responsible for the creation of the satellite detected rf signals. These regions are connected with the areas of strong radar returns from the NEXRAD Doppler radar system, indicating that they are from regions of intense convection. The authors will also show data from several storms detected in the extended Caribbean, in which the height profile of the source regions can be determined. Although as a single low earth orbit satellite FORTE cannot provide global coverage of thunderstorm/lightning events, follow-on satellite constellations should be able to provide detailed information on global lightning in near real-time.

  4. Ionospheric electron density irregularities observed by satellite-to-satellite, dual-frequency, low-low Doppler tracking link

    NASA Technical Reports Server (NTRS)

    Estes, R. D.; Grossi, M. D.

    1984-01-01

    A low-low, satellite-to-satellite, dual-frequency, Doppler tracking experiment was performed. The data are analyzed here for irregularities in electron density at the altitude of 212 km. The differential Doppler data with the relative motion term removed are integrated to obtain a representation of the electron density variation along the satellite path. Well-known large-scale features such as the equatorial geomagnetic anomaly and day/night ionization level differences are clearly observed in the integrated data. The larger crest of the morning geomagnetic anomaly is seen to occur in the southern (winter) hemisphere in agreement with previous observations. In addition, a sharp peak in the electron density at the day-to-night transition point is observed in two consecutive revolutions. This effect may be due to the previously postulated atmospheric shock wave generated by supersonic motion of the terminator.

  5. Modeling Prairie Pothole Lakes: Linking Satellite Observation and Calibration (Invited)

    NASA Astrophysics Data System (ADS)

    Schwartz, F. W.; Liu, G.; Zhang, B.; Yu, Z.

    2009-12-01

    This paper examines the response of a complex lake wetland system to variations in climate. The focus is on the lakes and wetlands of the Missouri Coteau, which is part of the larger Prairie Pothole Region of the Central Plains of North America. Information on lake size was enumerated from satellite images, and yielded power law relationships for different hydrological conditions. More traditional lake-stage data were made available to us from the USGS Cottonwood Lake Study Site in North Dakota. A Probabilistic Hydrologic Model (PHM) was developed to simulate lake complexes comprised of tens-of-thousands or more individual closed-basin lakes and wetlands. What is new about this model is a calibration scheme that utilizes remotely-sensed data on lake area as well as stage data for individual lakes. Some ¼ million individual data points are used within a Genetic Algorithm to calibrate the model by comparing the simulated results with observed lake area-frequency power law relationships derived from Landsat images and water depths from seven individual lakes and wetlands. The simulated lake behaviors show good agreement with the observations under average, dry, and wet climatic conditions. The calibrated model is used to examine the impact of climate variability on a large lake complex in ND, in particular, the “Dust Bowl Drought” 1930s. This most famous drought of the 20th Century devastated the agricultural economy of the Great Plains with health and social impacts lingering for years afterwards. Interestingly, the drought of 1930s is unremarkable in relation to others of greater intensity and frequency before AD 1200 in the Great Plains. Major droughts and deluges have the ability to create marked variability of the power law function (e.g. up to one and a half orders of magnitude variability from the extreme Dust Bowl Drought to the extreme 1993-2001 deluge). This new probabilistic modeling approach provides a novel tool to examine the response of the

  6. Satellite Observations of NO2 Trend over Romania

    PubMed Central

    Voiculescu, Mirela; Georgescu, Lucian

    2013-01-01

    Satellite-based measurements of atmospheric trace gases loading give a realistic image of atmospheric pollution at global, regional, and urban level. The aim of this paper is to investigate the trend of atmospheric NO2 content over Romania for the period 1996–2010 for several regions which are generally characterized by different pollutant loadings, resulting from GOME-1, SCIAMACHY, OMI, and GOME-2 instruments. Satellite results are then compared with ground-based in situ measurements made in industrial and relatively clean areas of one major city in Romania. This twofold approach will help in estimating whether the trend of NO2 obtained by means of data satellite retrievals can be connected with the evolution of national industry and transportation. PMID:24453819

  7. Small Satellite Constellations: The Future for Operational Earth Observation

    NASA Technical Reports Server (NTRS)

    Stephens, J. Paul

    2007-01-01

    Nanosat, microsat and minisat are low-cost, rapid-response small-satellites built from advanced terrestrial technology. SSTL delivers the benefits of affordable access to space through low-cost, rapid response, small satellites designed and built with state-of-the-art COTS technologies by: a) reducing the cost of entry into space; b) Achieving more missions within fixed budgets; c) making constellations and formation flying financially viable; d) responding rapidly from initial concept to orbital operation; and e) bringing the latest industrial COTS component advances to space. Growth has been stimulated in constellations for high temporal revisit&persistent monitoring and military responsive space assets.

  8. ECMWF's Global Snow Analysis: Assessment and Revision Based on Satellite Observations.

    NASA Astrophysics Data System (ADS)

    Drusch, Matthias; Vasiljevic, Drasko; Viterbo, Pedro

    2004-09-01

    Snow water equivalent and snow extent are key parameters for the earth's energy and water budget. In this study, the current operational snow-depth analysis (2D spatial Cressman interpolation) at the European Centre for Medium-Range Weather Forecasts (ECMWF), which relies on real-time observations of snow depth, the short-range forecast, and snow-depth climatic data, is presented. The operational product is compared with satellite-derived snow cover. It is found that the total area of grid boxes affected by snow is approximately 10% larger in the analysis than in the National Oceanic and Atmospheric Administration National Environmental Satellite, Data, and Information Service (NOAA/NESDIS) snow-extent product. The differences are persistent in time and space and cover the entire Northern Hemisphere. They comprise areas with intermittent and/or patchy snow cover, for example, the Tibetan Plateau, the edges of snow fields, and areas with a low density of observations, which are difficult to capture in the current operational analysis. A modified snow analysis is presented, in which the operational NESDIS snow product is incorporated. The current analysis and the revised analysis are compared with high-resolution snow-cover datasets derived from the Moderate-Resolution Imaging Spectroradiometer (MODIS) and independent ground-based snow-depth observations from the Meteorological Service of Canada. Using the NOAA/NESDIS snow-extent dataset in the operational analysis leads to a more realistic description of the actual snow extent.


  9. Observed Foreshock Ions which are Actually Behind the Martian Bow Shock

    NASA Astrophysics Data System (ADS)

    Frahm, Rudy A.; Yamauchi, Masatoshi; Winningham, J. David; Lundin, Rickard; Sharber, James R.; Nilsson, Hans; Coates, Andrew J.; Mukherjee, Joey

    2016-04-01

    The Mars Express (MEx) Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) experiment contains ion and electron instruments for conducting plasma measurements. On January 23, 2012, during in-bound travel of MEx in the southern hemisphere of Mars traveling from its dawn side toward periapsis at dusk, the plasma instruments measured foreshock-like ion beams extending from outside the bow shock and into the magnetosphere, continuing to a distance of about a proton gyroradius from the bow shock. These ion beams were mostly protons, were observed to have energies greater than solar wind protons, and were not gyrating, in agreement with reflections of the solar wind proton beam. Furthermore, in the foreshock region, the ion energy gradually decreased toward the magnetosheath, in agreement with an acceleration by an outward-directed electric field in the bow shock. The observations also suggest that this electric field exists even inside the magnetosheath, within the distance of a proton gyroradius from the bow shock.

  10. Outline of the survey on the development of earth observation satellites

    NASA Technical Reports Server (NTRS)

    1977-01-01

    An independent earth observation system with land and sea satellites to be developed by Japan is described. Visible and infrared radiometers, microwave radiometers, microwave scattermeters, synthetic aperture radar, and laser sensors are among the instrumentation discussed. Triaxial attitude control, basic technology common to sea and land observation satellites as well as land data analytical technology developed for U.S. LANDSAT data are reviewed.

  11. On the geometric analysis and adjustment of optical satellite observations. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Tsimis, E.

    1972-01-01

    Satellite geodesy methods were catagorized into three divisions: geometric, dynamic, and mixed. These catagories furnish the basis for distinction between geometric and dynamic satellite geodesy. The dual adjustment, geometric analysis, and Cartesian coodinate determination are examined for two observing stations. Similar illustrations are given when more than two observing stations are used.

  12. Satellites around Massive Galaxies Since z ~ 2: Confronting the Millennium Simulation with Observations

    NASA Astrophysics Data System (ADS)

    Quilis, Vicent; Trujillo, Ignacio

    2012-06-01

    Minor merging has been postulated as the most likely evolutionary path to produce the increase in size and mass observed in the massive galaxies since z ~ 2. In this Letter, we directly test this hypothesis, comparing the population of satellites around massive galaxies in cosmological simulations versus the observations. We use state-of-the-art, publically available, Millennium I and II simulations, and the associated semi-analytical galaxy catalogs to explore the time evolution of the fraction of massive galaxies that have satellites, the number of satellites per galaxy, the projected distance at which the satellites locate from the host galaxy, and the mass ratio between the host galaxies and their satellites. The three virtual galaxy catalogs considered here overproduce the fraction of galaxies with satellites by a factor ranging between 1.5 and 6 depending on the epoch, whereas the mean projected distance and ratio of the satellite mass over host mass are in closer agreement with data. The larger pull of satellites in the semi-analytical samples could suggest that the size evolution found in previous hydrodynamical simulations is an artifact due to the larger number of infalling satellites compared to the real universe. These results advise us to revise the physical ingredients implemented in the semi-analytical models in order to reconcile the observed and computed fraction of galaxies with satellites, and eventually, it would leave some room for other mechanisms explaining the galaxy size growth not related to the minor merging.

  13. Observations of Reflected Ions and Plasma Turbulence for Satellite Potentials Greater Than the Ion Ram Energy

    NASA Technical Reports Server (NTRS)

    Wright, K. H., Jr.; Stone, N. H.; Sorensen, J.; Winningham, J. D.; Gurgiolo, C.

    1997-01-01

    During the TSS-1R mission, the behavior of the ions flowing from the forward hemisphere of the Tethered Satellite System (TSS) satellite was examined as the potential on the satellite was changed from below to above 5 Volts. The ram energy of the ambient atomic oxygen ions is about 5 eV. For satellite potentials less than 5 V, no ions were observed on the ram side of the satellite. When the satellite potential was raised above 5 V, ions were observed to be flowing from the forward region of the satellite. In the region sampled, the ion flux was a few percent of the ambient with energies of about 5 eV. The temperature of the outflowing ions was observed to be enhanced, relative to the ambient ionosphere, and had a maximum in a plane containing the center of the satellite and normal to the geomagnetic field. The net current to the probe package became much more noisy for satellite potentials above 5 V as compared with satellite potentials below 5 V indicating a more disturbed plasma environment.

  14. SATELLITES AROUND MASSIVE GALAXIES SINCE z {approx} 2: CONFRONTING THE MILLENNIUM SIMULATION WITH OBSERVATIONS

    SciTech Connect

    Quilis, Vicent; Trujillo, Ignacio

    2012-06-20

    Minor merging has been postulated as the most likely evolutionary path to produce the increase in size and mass observed in the massive galaxies since z {approx} 2. In this Letter, we directly test this hypothesis, comparing the population of satellites around massive galaxies in cosmological simulations versus the observations. We use state-of-the-art, publically available, Millennium I and II simulations, and the associated semi-analytical galaxy catalogs to explore the time evolution of the fraction of massive galaxies that have satellites, the number of satellites per galaxy, the projected distance at which the satellites locate from the host galaxy, and the mass ratio between the host galaxies and their satellites. The three virtual galaxy catalogs considered here overproduce the fraction of galaxies with satellites by a factor ranging between 1.5 and 6 depending on the epoch, whereas the mean projected distance and ratio of the satellite mass over host mass are in closer agreement with data. The larger pull of satellites in the semi-analytical samples could suggest that the size evolution found in previous hydrodynamical simulations is an artifact due to the larger number of infalling satellites compared to the real universe. These results advise us to revise the physical ingredients implemented in the semi-analytical models in order to reconcile the observed and computed fraction of galaxies with satellites, and eventually, it would leave some room for other mechanisms explaining the galaxy size growth not related to the minor merging.

  15. The Martian satellites - 100 years on. [Phobos and Deimos observational history

    NASA Technical Reports Server (NTRS)

    Hunt, G. E.; Michael, W. H., Jr.; Pascu, D.; Veverka, J.; Wilkins, G. A.; Woolfson, M.

    1978-01-01

    Studies of Phobos and Deimos, the two satellites of Mars, may provide the best observations yet of the material populating the asteroid belt. Viking observations of Phobos showing crater chains and striations are analyzed, and Mariner-9 photometry exhibiting the albedo of the satellite is discussed. A mass determination for Phobos results in a value of 1.1 times 10 to the 19th power g; the mean density of the satellite is set at about 2 g per cu cm, a value suggesting formation of the satellite from material in the asteroid belt.

  16. ASPECTS OF ARCTIC SEA ICE OBSERVABLE BY SEQUENTIAL PASSIVE MICROWAVE OBSERVATIONS FROM THE NIMBUS-5 SATELLITE.

    USGS Publications Warehouse

    Campbell, William J.; Gloersen, Per; Zwally, H. Jay; ,

    1984-01-01

    Observations made from 1972 to 1976 with the Electrically Scanning Microwave Radiometer on board the Nimbus-5 satellite provide sequential synoptic information of the Arctic sea ice cover. This four-year data set was used to construct a fairly continuous series of three-day average 19-GHz passive microwave images which has become a valuable source of polar information, yielding many anticipated and unanticipated discoveries of the sea ice canopy observed in its entirety through the clouds and during the polar night. Short-term, seasonal, and annual variations of key sea ice parameters, such as ice edge position, ice types, mixtures of ice types, ice concentrations, and snow melt on the ice, are presented for various parts of the Arctic.

  17. Global Flood and Landslide Detection and Prediction Using Satellite Observations

    NASA Astrophysics Data System (ADS)

    Adler, R.; Yilmaz, K.; Hong, Y.; Kirschbaum, D.; Pierce, H.; Policelli, F.

    2009-04-01

    A global flood and landslide detection/prediction system is now running in real-time using satellite multi-satellite rainfall analysis in combination with hydrological models and algorithms to estimate key flood and landslide parameters (http://trmm.gsfc.nasa.gov/publications_dir/potential_flood_hydro.html). The system also uses satellite-based land surface information such as digital elevation information from the NASA SRTM (Shuttle Radar Terrain Mission) and vegetation information from MODIS in he model and algorithm calculations. Progress in using the TRMM Multi-satellite Precipitation Analysis (TMPA) as input to these flood and landslide forecasts is outlined, with case studies as well as validation in terms of flood/landslide events. Examples shown include the major flood in Burma in spring of 2008 and examples of floods and landslide events associated with tropical cyclones. The flood determination algorithm consists of three major components: 1) multi-satellite precipitation estimation; 2) characterization of land surface including digital elevation information and other surface information, topography-derived hydrologic parameters such as flow direction, flow accumulation, basin, and river network etc.; 3) a hydrological model to infiltrate rainfall and route overland runoff. Results of calculated water depth over a threshold are then displayed about six hours after real-time. Time-history of inundations are also calculated and displayed. Validation analysis indicates good results for flood detection and evolution, but with limitations in the current routing calculations. Global numerical weather prediction rainfall forecasts are being used experimentally to extend the period of utility of the flood information. In terms of landslides, the satellite rainfall information is combined with a global landslide susceptibility map, derived from a combination of global surface characteristics (digital elevation topography, slope, soil types, soil texture, and land

  18. Gas Flaring Volume Estimates with Multiple Satellite Observations

    NASA Astrophysics Data System (ADS)

    Ziskin, D. C.; Elvidge, C.; Baugh, K.; Ghosh, T.; Hsu, F. C.

    2010-12-01

    Flammable gases (primarily methane) are a common bi-product associated with oil wells. Where there is no infrastructure to use the gas or bring it to market, the gases are typically flared off. This practice is more common at remote sites, such as an offshore drilling platform. The Defense Meteorological Satellite Program (DMSP) is a series of satellites with a low-light imager called the Operational Linescan System (OLS). The OLS, which detects the flares at night, has been a valuable tool in the estimation of flared gas volume [Elvidge et al, 2009]. The use of the Moderate Resolution Imaging Spectroradiometer (MODIS) fire product has been processed to create products suitable for an independent estimate of gas flaring on land. We are presenting the MODIS flare product, the results of our MODIS gas flare volume analysis, and independent validation of the published DMSP estimates. Elvidge, C. D., Ziskin, D., Baugh, K. E., Tuttle, B. T., Ghosh, T., Pack, D. W., Erwin, E. H., Zhizhin, M., 2009, "A Fifteen Year Record of Global Natural Gas Flaring Derived from Satellite Data", Energies, 2 (3), 595-622

  19. Observations of Reflected Ions and Plasma Turbulence for Satellite Potentials Greater than the Ion Ram Energy

    NASA Technical Reports Server (NTRS)

    Wright, K. H., Jr.; Stone, N. H.; Sorensen, J.; Winningham, J. D.; Gurgiolo, C.

    1998-01-01

    During the TSS-1R mission, the behavior of the ions flowing from the forward hemisphere of the Tethered Satellite System (TSS) satellite was examined as the potential of the satellite was changed from below to above 5 V. The ram energy of the ambient atomic oxygen ions is approximately 5 eV. For satellite potentials less than 5 V, no ions were observed on the ram side of the satellite. When the satellite potential was raised greater than 5 V, ions were observed to be flowing from the forward region of the satellite. In the region sampled, the ion flux was a few percent of the ambient with energies of approximately 5 eV. The temperature of the out-flowing ions was observed to be enhanced, relative to the ambient ionosphere. The net current to the probe package became much more noisy for satellite potentials greater than 5 V as compared with satellite potentials less than 5 V, indicating a more disturbed plasma environment.

  20. Research on earth observing satellite segmenting and scheduling problem for area targets

    NASA Astrophysics Data System (ADS)

    He, Renjie; Ruan, Qiming

    2005-10-01

    The mission of an Earth Observing Satellite (EOS) is to acquire images of specified areas on the Earth surface, in response to observation requests from customers for strategic, environmental, commercial, agricultural, and civil analysis and research. A target imaged can have one out of two shapes: a spot and a large polygonal area. A spot can be covered by a single scene of satellite sensor, while a polygonal area may require cutting-up into several contiguous strips to be completely imaged. Because of the orbit restriction, satellite can only view target during specific windows of opportunity when flying over the target. Furthermore, the satellite can only be tasked during such access time windows. Hence a scheduling method of satellite observing tasks has to be taken into account for utilizing satellite sensor efficiently. This paper intends to solve a specific segmenting and scheduling problem for area targets, which concerned with an optical observing satellite equipped with line array CCD sensor. In the paper, based on the analysis of characters of satellite sensor and observed area target, a new method of segmenting area target is given. And on the basis of segmenting results of area target, a scheduling model for multi area targets is proposed. In the paper end, experimental results and analysis are also presented.

  1. Present status and future plans of the Japanese earth observation satellite program

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Kiyoshi; Arai, Kohei; Igarashi, Tamotsu

    Japan is now operating 3 earth observation satellites, i. e. MOS-1 (Marine Observation Satellite-1, Momo-1 in Japanese), EGS (Experimental Geodetic Satellite, Ajisai in Japanese) and GMS (Geostationary Meteorological Satellite, Himawari in Japanese). MOS-1 has 3 different sensors, MESSR (Multispectral Electronic Self Scanning Radiometer), VTIR (Visible and Thermal Infrared Radiometer) and MSR (Microwave Scanning Radiometer) in addition to DCS (Data Collection System). GMS has two sensors, VISSR (Visible and IR Spin Scan Radiometer) and SEM (Solar Environmental Monitor). EGS is equipped with reflecting mirrors of the sun light and laser reflecters. For the future earth observation satellites, ERS-1 (Earth Resources Satellite-1), MOS-1b, ADEOS (Advanced Earth Observing Satellite) are under development. Two sensors, AMSR (Advanced Microwave Scanning Radiometer) and ITIR (Intermediate Thermal IR Radiometer) for NASA's polar platform are initial stage of development. Study and planning are made for future earth observation satellites including Japanese polor platform, TRMM, etc.). The study for the second generation GMS has been made by the Committee on the Function of Future GMS under the request of Japan Meteorological Agency in FY 1987.

  2. Understanding the relationship between actual and potential evapotranspirations from long- term water balance analysis and flux observation

    NASA Astrophysics Data System (ADS)

    Yang, D.; Yang, H.; Sun, F.

    2007-12-01

    potential evaporations are plotted against the time (year) during the same period. This means that complementary idea cannot provide universally correct predictions on the trend of actual evaporation only from the potential one. In this research, we examine the coupled water-energy balance based on Budyko hypothesis and proposed a conceptual model for predicting the inter-annual variability of annual water balance, and the change trends of water balances due to climate changes. The wet environment evaporation was defined as the boundary condition in the Bouchet hypothesis and introduced into complementary relationship (CR), which combined the actual evaporation with potential evaporation in an equation. However, the CR was derived in a closed system where no horizontal energy advection existed. The effect of the horizontal advection on the CR in a real open system was also analyzed in this study. Using the long-term water balance analysis in the 108 study catchments and flux observation at 7 sites in Asia monsoon region, the regional and seasonal variability of the complementary relationship was examined. Key Words: climate change, evapotranspiration, water balance, flux observation, Budyko hypothesis, Bouchet hypothesis

  3. An analysis of satellite state vector observability using SST tracking data

    NASA Technical Reports Server (NTRS)

    Englar, T. S., Jr.; Hammond, C. L.

    1976-01-01

    Observability of satellite state vectors, using only SST tracking data was investigated by covariance analysis under a variety of satellite and station configurations. These results indicate very precarious observability in most short arc cases. The consequences of this are large variances on many state components, such as the downrange component of the relay satellite position. To illustrate the impact of observability problems, an example is given of two distinct satellite orbit pairs generating essentially the same data arc. The physical bases for unobservability are outlined and related to proposed TDRSS configurations. Results are relevant to any mission depending upon TDRSS to determine satellite state. The required mathematical analysis and the software used is described.

  4. Astrometric observations of Saturn's satellites from McDonald Observatory, 1972. [using reference stars

    NASA Technical Reports Server (NTRS)

    Abbot, R. I.; Mulholland, J. D.; Shelus, P. J.

    1974-01-01

    Observations of Saturn's satellites were reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey (PSS) plates. This involved the use of 39 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two plate measurement and reduction techniques on the satellite measurements demonstrate the existence of a serious background gradient effect and the utility of microdensitometry to eliminate this error source in positional determinations of close satellites.

  5. Satellite observed global vegetation dynamics and its relations with biosphere-atmosphere carbon exchange

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.; Fung, I. Y.

    1989-01-01

    Satellite observations of visible and near-infrared reflectances and brightness temperatures at 37 GHz frequency are studied to quantify spatial and temporal variations of land-surface vegetation. These satellite data are further correlated with the temporal variations of the atmospheric CO2 concentration and the terrestrial primary productivity.

  6. The influence of regional surface soil moisture anomalies on forest fires in Siberia observed from satellites

    NASA Astrophysics Data System (ADS)

    Bartsch, A.; Balzter, H.; George, C.

    2009-10-01

    Forest fires are frequent in the Siberian taiga and are predicted to increase in frequency as a result of increased fire risk under drought conditions, and prolonged fire seasons caused by climate change. There is, however, some uncertainty as to the extent to which drought influences forest fire frequency at a regional scale. Here, we present an analysis of satellite derived soil moisture anomaly data from ERS-1/2 (ERS: Earth Resources Satellite) scatterometer data and burned area maps from MODIS/AVHRR/ATSR (Moderate Resolution Imaging Spectroradiometer/Advanced Very High Resolution Radiometer/Along-Track Scanning Radiometer) over Central Siberia for the years 1992-2000. The purpose of this study is to investigate the relationship of remotely sensed soil moisture deviations from the long-term mean and fire within the boreal biome on a sub-continental scale. Results show that wet surface soil moisture conditions limit the extent of burned area. They can prevent the outbreak of fires but the magnitude of a negative (dry) deviation does not determine the maximum size of fire affected areas. It is known from the literature, however, that an ignition is more likely to occur under low surface wetness conditions, such as those that we observed during July and August in both permafrost and non-permafrost regions. Although the burned area under drier conditions in July is lowest over non-permafrost, the actual number of fires is as high as over continuous permafrost. Approximately 80% of all events occurred under such conditions during that month. The fire size was below 50 km2 under moist conditions. Larger burned areas have in general not been detected when the surface wetness deviation exceeded +5%.

  7. Online Resource for Earth-Observing Satellite Sensor Calibration

    NASA Technical Reports Server (NTRS)

    McCorkel, J.; Czapla-Myers, J.; Thome, K.; Wenny, B.

    2015-01-01

    The Radiometric Calibration Test Site (RadCaTS) at Railroad Valley Playa, Nevada is being developed by the University of Arizona to enable improved accuracy and consistency for airborne and satellite sensor calibration. Primary instrumentation at the site consists of ground-viewing radiometers, a sun photometer, and a meteorological station. Measurements made by these instruments are used to calculate surface reflectance, atmospheric properties and a prediction for top-of-atmosphere reflectance and radiance. This work will leverage research for RadCaTS, and describe the requirements for an online database, associated data formats and quality control, and processing levels.

  8. Satellite observations of smoke from oil fires in kuwait.

    PubMed

    Limaye, S S; Suomi, V E; Velden, C; Tripoli, G

    1991-06-14

    Extensive dark smoke clouds associated with burning oil wells in Kuwait have been seen in data from weather satellites since early February 1991. The smoke is dispersed over a wide area. Variable and strong low level winds have held most of the smoke plume below 3 to 5 kilometers within a few hundred kilometers of the source. Thin veils of smoke have been detected in METEOSAT data as far away as 2000 kilometers east of Kuwait, over southwestern Pakistan at heights between 6 and 7 kilometers. The occasional presence of convective clouds over the fires indicates that some scavenging of the smoke is taking place.

  9. Wind waves in tropical cyclones: satellite altimeter observations and modeling

    NASA Astrophysics Data System (ADS)

    Golubkin, Pavel; Kudryavtsev, Vladimir; Chapron, Bertrand

    2016-04-01

    Results of investigation of wind-wave generation by tropical cyclones using satellite altimeter data are presented. Tropical cyclones are generally relatively small rapidly moving low pressure systems that are capable of generating severe wave conditions. Translation of a tropical cyclone leads to a prolonged period of time surface waves in the right sector remain under high wind forcing conditions. This effect has been termed extended fetch, trapped fetch or group velocity quasi-resonance. A tropical cyclone wave field is thus likely more asymmetrical than the corresponding wind field: wind waves in the tropical cyclone right sector are more developed with larger heights than waves in the left one. A dataset of satellite altimeter intersections of the Western Pacific tropical cyclones was created for 2010-2013. Data from four missions were considered, i.e., Jason-1, Jason-2, CryoSat-2, SARAL/AltiKa. Measurements in the rear-left and front-right sectors of tropical cyclones were examined for the presence of significant wave asymmetry. An analytical model is then derived to efficiently describe the wave energy distribution in a moving tropical cyclone. The model essentially builds on a generalization of the self-similar wave growth model and the assumption of a strongly dominant single spectral mode in a given quadrant of the storm. The model provides a criterion to anticipate wave enhancement with the generation of trapped abnormal waves. If forced during a sufficient timescale interval, also defined from this generalized self-similar wave growth model, waves can be trapped and large amplification of the wave energy will occur in the front-right storm quadrant. Remarkably, the group velocity and corresponding wavelength of outrunning wave systems will become wind speed independent and solely relate to the translating velocity. The resulting significant wave height also only weakly depends on wind speed, and more strongly on the translation velocity. Satellite

  10. Recent observations with the Soviet Union's GLONASS navigation satellites

    NASA Astrophysics Data System (ADS)

    Dale, S. A.; Daly, P.

    An evaluation is made of the Soviet Global Orbiting Navigation Satellite System, 'GLONASS', which is currently preoperational and exhibits parallels with the Navstar GPS. Attention is given to the GLONASS orbital features and RF signal characteristics and channelization. Although GLONASS carries a C/A code at L1 and a P code at both L1 and L2, as Navstar does, additional features take the form of spectral lines at the P-code nulls and, in some cases, a carrier at the L2 center frequency. Code length and rate, being only about half those of Navstar, indicate a rather inferior jamming margin and half the pseudorange resolution.

  11. Some 'lost' observations from McDonald Observatory of the faint outer satellites of Jupiter

    NASA Astrophysics Data System (ADS)

    Shelus, Peter J.; Whipple, Arthur L.; Benedict, G. F.; Mulholland, J. D.

    1992-08-01

    Attention is given to a number of photographic exposures of the faint outer satellites of Jupiter that were taken with the 2.1-m Otto Struve reflector at McDonald Observatory in the late 1970s and early 1980s. The plates, together with the relevant observing logs, were measured and reduced. Observed positions and corrected and deleted observations of Jovian satellites are presented.

  12. NASA Perspectives on Earth Observations from Satellite or 50 Years of Meteorological Satellite Experiments-The NASA Perspective

    NASA Technical Reports Server (NTRS)

    Einaudi, Franco

    2010-01-01

    The NASA was established in 1959. From those very eady days to the present NASA has been intimately involved with NOAA and the scientific community in the development and operation of satellite and sensor experiments. The early efforts included experiments on the TIROS and geostationary Applications Technology Satellites (ATS) series. In the latter case the spin-scan cameras conceived by Verner Suomi, along with the TIROS cameras, opened new vistas at what could be done in meteorological studies with the daily, nearly global, synoptic views from space-borne sensors As the years passed and the Nimbus series of satellites came into being in the 1960's, more quantitative observations with longer-lifetime, increasingly capable, better calibrated instruments came into being. NASA, in collaboration with and in support of NOAA, implemented operational systems that we now know as the Polar Operational Environmental Satellite (POES) series and the Geostationary Operational Environmental Satellite (GOES) series that provided dependable, continuous, dedicated satellite observations for use by the weather and atmospheric science communities. Through the 1970's, 1980's, and 1990's improved, well-calibrated instruments with more spectral bands extending into the thermal and the microwave portions of the electromagnetic spectrum were provided to obtain accurate soundings of the atmosphere, atmospheric chemistry constituents such as ozone, global sea surface temperature, snow and ice extent, vegetation dynamics, etc. In the 1990's and up to the present the NASA/Earth Observing System (EOS) has been developed, implemented, and operated over many years to provide a very comprehensive suite of observations of the atmosphere, as well as land and ocean parameters. The future looks bright wherein the development of new systems, broadly described by the National Academy of Science Decadal Study, is now underway. NASA, along with collaborations with NOAA, other agencies, and the

  13. Spatial evaluation of volcanic ash forecasts using satellite observations

    NASA Astrophysics Data System (ADS)

    Harvey, N. J.; Dacre, H. F.

    2015-09-01

    The decision to close airspace in the event of a volcanic eruption is based on hazard maps of predicted ash extent. These are produced using output from volcanic ash transport and dispersion (VATD) models. In this paper an objective metric to evaluate the spatial accuracy of VATD simulations relative to satellite retrievals of volcanic ash is presented. The metric is based on the fractions skill score (FSS). This measure of skill provides more information than traditional point-by-point metrics, such as success index and Pearson correlation coefficient, as it takes into the account spatial scale over which skill is being assessed. The FSS determines the scale over which a simulation has skill and can differentiate between a "near miss" and a forecast that is badly misplaced. The idealised scenarios presented show that even simulations with considerable displacement errors have useful skill when evaluated over neighbourhood scales of 200-700 km2. This method could be used to compare forecasts produced by different VATDs or using different model parameters, assess the impact of assimilating satellite retrieved ash data and evaluate VATD forecasts over a long time period.

  14. Spatial evaluation of volcanic ash forecasts using satellite observations

    NASA Astrophysics Data System (ADS)

    Harvey, N. J.; Dacre, H. F.

    2016-01-01

    The decision to close airspace in the event of a volcanic eruption is based on hazard maps of predicted ash extent. These are produced using output from volcanic ash transport and dispersion (VATD) models. In this paper the fractions skill score has been used for the first time to evaluate the spatial accuracy of VATD simulations relative to satellite retrievals of volcanic ash. This objective measure of skill provides more information than traditional point-by-point metrics, such as success index and Pearson correlation coefficient, as it takes into the account spatial scale over which skill is being assessed. The FSS determines the scale over which a simulation has skill and can differentiate between a "near miss" and a forecast that is badly misplaced. The idealized scenarios presented show that even simulations with considerable displacement errors have useful skill when evaluated over neighbourhood scales of 200-700 (km)2. This method could be used to compare forecasts produced by different VATDs or using different model parameters, assess the impact of assimilating satellite-retrieved ash data and evaluate VATD forecasts over a long time period.

  15. Evaluation of Long-Term Cloud-Resolving Model Simulations Using Satellite Radiance Observations and Multi-Frequency Satellite Simulators

    NASA Technical Reports Server (NTRS)

    Matsui, Toshihisa; Zeng, Xiping; Tao, Wei-Kuo; Masunaga, Hirohiko; Olson, William S.; Lang, Stephen

    2008-01-01

    This paper proposes a methodology known as the Tropical Rainfall Measuring Mission (TRMM) Triple-Sensor Three-step Evaluation Framework (T3EF) for the systematic evaluation of precipitating cloud types and microphysics in a cloud-resolving model (CRM). T3EF utilizes multi-frequency satellite simulators and novel statistics of multi-frequency radiance and backscattering signals observed from the TRMM satellite. Specifically, T3EF compares CRM and satellite observations in the form of combined probability distributions of precipitation radar (PR) reflectivity, polarization-corrected microwave brightness temperature (Tb), and infrared Tb to evaluate the candidate CRM. T3EF is used to evaluate the Goddard Cumulus Ensemble (GCE) model for cases involving the South China Sea Monsoon Experiment (SCSMEX) and Kwajalein Experiment (KWAJEX). This evaluation reveals that the GCE properly captures the satellite-measured frequencies of different precipitating cloud types in the SCSMEX case but underestimates the frequencies of deep convective and deep stratiform types in the KWAJEX case. Moreover, the GCE tends to simulate excessively large and abundant frozen condensates in deep convective clouds as inferred from the overestimated GCE-simulated radar reflectivities and microwave Tb depressions. Unveiling the detailed errors in the GCE s performance provides the best direction for model improvements.

  16. An EOF Iteration Approach for Obtaining Homogeneous Radiative Fluxes from Satellites Observations

    NASA Technical Reports Server (NTRS)

    Zhang, Banglin; Pinker, Rachel T.; Stackhouse, Paul W., Jr.

    2007-01-01

    Conventional observations of climate parameters are sparse in space and/or in time and the representativeness of such information needs to be optimized. Observations from satellites provide improved spatial coverage than point observations however they pose new challenges for obtaining homogeneous coverage. Surface radiative fluxes, the forcing functions of the hydrologic cycle and biogeophysical processes, are now becoming available from global scale satellite observations. They are derived from independent satellite platforms and sensors that differ in temporal and spatial resolution and in the size of the footprint from which information is derived. Data gaps, degraded spatial resolution near boundaries of geostationary satellites, and different viewing geometries in areas of satellite overlap, could result in biased estimates of radiative fluxes. In this study, discussed will be issues related to the sources of inhomogeneity in surface radiative fluxes as derived from satellites; development of an approach to obtain homogeneous data sets; and application of the methodology to the widely used International Satellite Cloud Climatology Project (ISCCP) data that currently serve as a source of information for deriving estimates of surface and top of the atmosphere radiative fluxes. Introduced is an Empirical Orthogonal Function (EOF) iteration scheme for homogenizing the fluxes. The scheme is evaluated in several ways including comparison of the inferred radiative fluxes against ground observations, both before and after the EOF approach is applied. On the average, the latter reduces the rms error by about 2-3 W/m2.

  17. A preliminary global oceanic cloud climatology from satellite albedo observations

    NASA Technical Reports Server (NTRS)

    Hughes, N. A.; Henderson-Sellers, A.

    1983-01-01

    A predictive relationship is developed between over-ocean cloud system albedo and the cloud amount present, using as a data base ERB satellite microwave readings at 0.5-0.7 micron and the USAF three-dimensional nephanalysis archive. The ERB data provided global coverage at a resolution of 2.5 x 2.5 deg during the 1974-78 period. Regression analyses were performed on the amounts and albedos for several years of data for one month in order to detect seasonal variations. A logarithmic relationship was found between the cloud system albedo and cloud amount over the oceans, with negligible seasonal variance. The analysis is noted to apply only where low surface albedos are encountered, and further work to extend the study to continental vegetated areas is indicated.

  18. Genesis of tropical cyclone Nargis revealed by multiple satellite observations

    NASA Astrophysics Data System (ADS)

    Kikuchi, Kazuyoshi; Wang, Bin; Fudeyasu, Hironori

    2009-03-01

    Tropical cyclone (TC) Nargis recently battered Myanmar on May 2 2008 is one of the most deadly tropical storms in history. Nargis was initiated by an abnormally strong intraseasonal westerly event associated with Madden-Julian oscillation (MJO) in the eastern Indian Ocean. An incipient cyclonic disturbance emerged as an emanation of Rossby wave-induced vortex when the intraseasonal convective anomaly reached the Maritime Continent. The northeastward movement of MJO convection facilitated further development of the disturbance. The incipient disturbance became a tropical disturbance (TD) with a central warm-core structure on April 26. The further development from the TD to TC formation on April 28 is characterized by two distinctive stages: a radial contraction followed by a rapid intensification. The processes responsible for contraction and rapid intensification are discussed by diagnosis of multiple satellite data. This proposed new scenario is instrumental for understanding how a major TC develops in the northern Indian Ocean.

  19. Fuel models and fire potential from satellite and surface observations

    USGS Publications Warehouse

    Burgan, R.E.; Klaver, R.W.; Klarer, J.M.

    1998-01-01

    A national 1-km resolution fire danger fuel model map was derived through use of previously mapped land cover classes and ecoregions, and extensive ground sample data, then refined through review by fire managers familiar with various portions of the U.S. The fuel model map will be used in the next generation fire danger rating system for the U.S., but it also made possible immediate development of a satellite and ground based fire potential index map. The inputs and algorithm of the fire potential index are presented, along with a case study of the correlation between the fire potential index and fire occurrence in California and Nevada. Application of the fire potential index in the Mediterranean ecosystems of Spain, Chile, and Mexico will be tested.

  20. Non-Stationary Internal Tides Observed with Satellite Altimetry

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Zaron, E. D.

    2011-01-01

    Temporal variability of the internal tide is inferred from a 17-year combined record of Topex/Poseidon and Jason satellite altimeters. A global sampling of along-track sea-surface height wavenumber spectra finds that non-stationary variance is generally 25% or less of the average variance at wavenumbers characteristic of mode-l tidal internal waves. With some exceptions the non-stationary variance does not exceed 0.25 sq cm. The mode-2 signal, where detectable, contains a larger fraction of non-stationary variance, typically 50% or more. Temporal subsetting of the data reveals interannual variability barely significant compared with tidal estimation error from 3-year records. Comparison of summer vs. winter conditions shows only one region of noteworthy seasonal changes, the northern South China Sea. Implications for the anticipated SWOT altimeter mission are briefly discussed.

  1. Satellite Altimeter Observations of Black Sea Level Variations

    NASA Technical Reports Server (NTRS)

    Korotaev, G. K.; Saenko, O. A.; Koblinsky, C. J.

    1998-01-01

    Satellite altimeter data from TOPEX/POSEIDON and ERS-1 are used to examine seasonal and mesoscale variability of the Black Sea level. Consistent processing procedures of the altimeter measurements make it possible to determine the dynamical Black Sea level with an rms accuracy about 3 cm. It is shown that the Black Sea circulation intensifies in the winter-spring seasons and attenuates in summer-autumn. The seasonal variability of sea level is accompanied by a radiation of Rossby waves from the eastern coast of the basin. Mesoscale oscillations of the dynamical sea level are found to vary spatially and temporarily. Usually, strong eddy intensity is associated with instabilities of the Rim Current. Away from this circulation feature, in the deep basin, mesoscale variability is much smaller. Mesoscale variability has a strong seasonal signal, which is out of phase with the strength of the Rim Current.

  2. Application of high resolution satellite observations to monitor urban ecosystems

    NASA Astrophysics Data System (ADS)

    Gorokhova, I. N.

    2011-02-01

    Topographic identification and mapping were carried out for different key plots in Moscow according to satellite images using geoinformation technologies; a complex ecological map was constructed for the key plots. The main advantage of this project is using the remote information for obtaining quick-look data on the ecosystem's state. The following ecological parameters were determined during the mapping: the percentage of forest area, the canopy's density, and the sites of forest uprooting in forests-parks; the recreational load on the soil cover in the forests, valleys of small rivers, and public gardens; the areas of disturbances of the herbaceous cover and soil overcompaction in lawns; the vertical and lateral structure of line plantings in community landscapes; and the disturbances in the land use in the territory of water-control areas of small rivers.

  3. A QUANTITATIVE EXPLANATION OF THE OBSERVED POPULATION OF MILKY WAY SATELLITE GALAXIES

    SciTech Connect

    Koposov, Sergey E.; Rix, Hans-Walter; Maccio, Andrea V.; Yoo, Jaiyul; Weinberg, David H.; Escude, Jordi Miralda

    2009-05-10

    We revisit the well known discrepancy between the observed number of Milky Way (MW) dwarf satellite companions and the predicted population of cold dark matter (CDM) subhalos, in light of the dozen new low-luminosity satellites found in imaging data from the Sloan Digital Sky Survey (SDSS) and our recent calibration of the SDSS satellite detection efficiency, which implies a total satellite population far larger than these dozen discoveries. We combine a detailed dynamical model for the CDM subhalo population with simple, physically motivated prescriptions for assigning a stellar content to each subhalo, then apply observational selection effects and compare to the current observational census. Reconciling the observed satellite population with CDM predictions still requires strong mass-dependent suppression of star formation in low-mass subhalos: models in which the stellar mass is a constant fraction F {sub *}({omega} {sub b}/{omega} {sub m}) of the subhalo mass M {sub sat} at the time it becomes a satellite fail for any choice of F {sub *}. However, previously advocated models that invoke suppression of gas accretion after reionization in halos with circular velocity V {sub circ} {<=} V {sub crit} {approx} 35 km s{sup -1} can reproduce the observed satellite counts for -15 {<=} M{sub V} {<=} 0. Successful models require F {sub *} {approx} 10{sup -3} in halos with V {sub circ}>V {sub crit} and strong suppression of star formation before reionization in halos with V {sub circ} {approx}< 10 km s{sup -1}; models without pre-reionization suppression predict far too many satellites with -5 {<=} M{sub V} {<=} 0. In this successful model, the dominant fraction of stars formed after reionization at all luminosities. Models that match the satellite luminosity distribution also match the observed heliocentric radius distribution, and they reproduce the observed characteristic stellar velocity dispersion {sigma}{sub *} {approx} 5-10 km s{sup -1} of the SDSS dwarfs given the

  4. Characterization of Spectral Absorption Properties of Aerosols Using Satellite Observations

    NASA Technical Reports Server (NTRS)

    Torres, O.; Jethva, H.; Bhartia, P. K.; Ahn, C.

    2012-01-01

    The wavelength-dependence of aerosol absorption optical depth (AAOD) is generally represented in terms of the Angstrom Absorption Exponent (AAE), a parameter that describes the dependence of AAOD with wavelength. The AAE parameter is closely related to aerosol composition. Black carbon (BC) containing aerosols yield AAE values near unity whereas Organic carbon (OC) aerosol particles are associated with values larger than 2. Even larger AAE values have been reported for desert dust aerosol particles. Knowledge of spectral AAOD is necessary for the calculation of direct radiative forcing effect of aerosols and for inferring aerosol composition. We have developed a satellitebased method of determining the spectral AAOD of absorbing aerosols. The technique uses high spectral resolution measurements of upwelling radiation from scenes where absorbing aerosols lie above clouds as indicated by the UV Aerosol Index. For those conditions, the satellite measured reflectance (rho lambda) is approximately given by Beer's law rho lambda = rho (sub 0 lambda) e (exp -mtau (sub abs lambda)) where rho(sub 0 lambda) is the cloud reflectance, m is the geometric slant path and tau (sub abs lambda) is the spectral AAOD. The rho (sub 0 lambda) term is determined by means of radiative transfer calculations using as input the cloud optical depth derived as described in Torres et al. [JAS, 2012] that accounts for the effects of aerosol absorption. In the second step, corrections for molecular and aerosol scattering effects are applied to the cloud reflectance term, and the spectral AAOD is then derived by inverting the equation above. The proposed technique will be discussed in detail and application results will be presented. The technique can be easily applied to hyper-spectral satellite measurements that include UV such as OMI, GOME and SCIAMACHY, or to multi-spectral visible measurements by other sensors provided that the aerosol-above-cloud events are easily identified.

  5. Tropospheric Emission Spectrometer (TES) for the Earth Observing System (EOS) CHEM Satellite

    NASA Technical Reports Server (NTRS)

    Beer, R.; Glavich, T.; Rider, D.

    2000-01-01

    The Tropospheric Emission Spectrometer (TES) is an imaging infrared Fourier transform spectrometer scheduled to be launched into polar sun-synchronous orbit on the Earth Observing System (EOS) CHEM satellite in December 2002.

  6. Astrometry of the main satellites of Uranus: 18 years of observations

    NASA Astrophysics Data System (ADS)

    Camargo, J. I. B.; Magalhães, F. P.; Vieira-Martins, R.; Assafin, M.; Braga-Ribas, F.; Dias-Oliveira, A.; Benedetti-Rossi, G.; Gomes-Júnior, A. R.; Andrei, A. H.; da Silva Neto, D. N.

    2015-10-01

    Context. We contribute to developing dynamical models of the motions of Uranus' main satellites. Aims: We determine accurate positions of the main satellites of Uranus: Miranda, Ariel, Umbriel, Titania, and Oberon. Positions of Uranus, as derived from those of these satellites, are also determined. The observational period spans from 1992 to 2011. All runs were made at the Pico dos Dias Observatory, Brazil. Methods: We used the software called Platform for Reduction of Astronomical Images Automatically (PRAIA) to perform a digital coronography to minimise the influence of the scattered light of Uranus on the astrometric measurements and to determine accurate positions of the main satellites. The positions of Uranus were then indirectly determined by computing the mean differences between the observed and ephemeris positions of these satellites. A series of numerical filters was applied to filter out spurious data. These filters are mostly based on (a) the comparison between the positions of Oberon with those of the other satellites and on (b) the offsets as given by the differences between the observed and ephemeris positions of all satellites. Results: We have, for the overall offsets of the five satellites, -29 mas (±63 mas) in right ascension and -27 mas (±46 mas) in declination. For the overall difference between the offsets of Oberon and those of the other satellites, we have +3 mas (±30 mas) in right ascension and -2 mas (±28 mas) in declination. Ephemeris positions for the satellites were determined from DE432+ura111. Comparisons using other modern ephemerides for the solar system - INPOP13c - and for the motion of the satellites - NOE-7-2013 - were also made. They confirm that the largest contribution to the offsets we find comes from the motion of the barycenter of the Uranus system around the barycenter of the solar system, as given by the planetary ephemerides. For the period from 1992 to 2011, our final catalogues contain 584 observed positions of

  7. Simultaneous ground- and satellite-based observation of MF/HF auroral radio emissions

    NASA Astrophysics Data System (ADS)

    Sato, Yuka; Kumamoto, Atsushi; Katoh, Yuto; Shinbori, Atsuki; Kadokura, Akira; Ogawa, Yasunobu

    2016-05-01

    We report on the first simultaneous measurements of medium-high frequency (MF/HF) auroral radio emissions (above 1 MHz) by ground- and satellite-based instruments. Observational data were obtained by the ground-based passive receivers in Iceland and Svalbard, and by the Plasma Waves and Sounder experiment (PWS) mounted on the Akebono satellite. We observed two simultaneous appearance events, during which the frequencies of the auroral roar and MF bursts detected at ground level were different from those of the terrestrial hectometric radiation (THR) observed by the Akebono satellite passing over the ground-based stations. This frequency difference confirms that auroral roar and THR are generated at different altitudes across the F peak. We did not observe any simultaneous observations that indicated an identical generation region of auroral roar and THR. In most cases, MF/HF auroral radio emissions were observed only by the ground-based detector, or by the satellite-based detector, even when the satellite was passing directly over the ground-based stations. A higher detection rate was observed from space than from ground level. This can primarily be explained in terms of the idea that the Akebono satellite can detect THR emissions coming from a wider region, and because a considerable portion of auroral radio emissions generated in the bottomside F region are masked by ionospheric absorption and screening in the D/E regions associated with ionization which results from auroral electrons and solar UV radiation.

  8. Galileo satellite antenna modeling

    NASA Astrophysics Data System (ADS)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  9. Comparison of Satellite Observations of Nitrogen Dioxide to Surface Monitor Nitrogen Dioxide Concentration

    NASA Technical Reports Server (NTRS)

    Kleb, Mary M.; Pippin, Margaret R.; Pierce, R. Bradley; Neil, Doreen O.; Lingenfelser, Gretchen; Szykman, James J.

    2006-01-01

    Nitrogen dioxide is one of the U. S. EPA s criteria pollutants, and one of the main ingredients needed for the production of ground-level ozone. Both ozone and nitrogen dioxide cause severe public health problems. Existing satellites have begun to produce observational data sets for nitrogen dioxide. Under NASAs Earth Science Applications Program, we examined the relationship between satellite observations and surface monitor observations of this air pollutant to examine if the satellite data can be used to facilitate a more capable and integrated observing network. This report provides a comparison of satellite tropospheric column nitrogen dioxide to surface monitor nitrogen dioxide concentration for the period from September 1996 through August 1997 at more than 300 individual locations in the continental US. We found that the spatial resolution and observation time of the satellite did not capture the variability of this pollutant as measured at ground level. The tools and processes developed to conduct this study will be applied to the analysis of advanced satellite observations. One advanced instrument has significantly better spatial resolution than the measurements studied here and operates with an afternoon overpass time, providing a more representative distribution for once-per-day sampling of this photochemically active atmospheric constituent.

  10. Spatiotemporal variability of methane over the Amazon from satellite observations

    NASA Astrophysics Data System (ADS)

    Ribeiro, Igor Oliveira; de Souza, Rodrigo Augusto Ferreira; Andreoli, Rita Valéria; Kayano, Mary Toshie; Costa, Patrícia dos Santos

    2016-07-01

    The spatiotemporal variability of the greenhouse gas methane (CH4) in the atmosphere over the Amazon is studied using data from the space-borne measurements of the Atmospheric Infrared Sounder on board NASA's AQUA satellite for the period 2003-12. The results show a pronounced variability of this gas over the Amazon Basin lowlands region, where wetland areas occur. CH4 has a well-defined seasonal behavior, with a progressive increase of its concentration during the dry season, followed by a decrease during the wet season. Concerning this variability, the present study indicates the important role of ENSO in modulating the variability of CH4 emissions over the northern Amazon, where this association seems to be mostly linked to changes in flooded areas in response to ENSO-related precipitation changes. In this region, a CH4 decrease (increase) is due to the El Niño-related (La Niña-related) dryness (wetness). On the other hand, an increase (decrease) in the biomass burning over the southeastern Amazon during very dry (wet) years explains the increase (decrease) in CH4 emissions in this region. The present analysis identifies the two main areas of the Amazon, its northern and southeastern sectors, with remarkable interannual variations of CH4. This result might be useful for future monitoring of the variations in the concentration of CH4, the second-most important greenhouse gas, in this area.

  11. Accessing Recent Trend of Land Surface Temperature from Satellite Observations

    NASA Astrophysics Data System (ADS)

    Shen, S.; Leptoukh, G. G.; Romanov, P.

    2011-12-01

    Land surface temperature (LST) is an important element to measure the state of the terrestrial ecosystems and to study the surface energy budgets. In support of the land cover/land use change related international program MAIRS (Monsoon Asia Integrated Regional Study), we have collected the global monthly LST measured by MODIS since the beginning of the missions. The MODIS LST time series have ~11 years of data from Terra since 2000 and ~9 years of data from Aqua since 2002, which makes possible to study the recent climate, such as trend and variability. In this study, monthly climatology from two satellite platforms are calculated and compared. The spatial patterns of LST trends are accessed, focusing on the Asian Monsoon region. Furthermore, the MODIS LST trends are compared with the skin temperature trend from the NASA's atmospheric assimilation model, MERRA (MODERN ERA RETROSPECTIVE-ANALYSIS FOR RESEARCH AND APPLICATIONS), which has longer data record since 1979. The calculated climatology and anomaly of MODIS LST will be integrated into the online visualization system, Giovanni, at NASA GES DISC for easy access and use by scientists and general public.

  12. Observations of the Natural Planetary Satellites for Dynamical and Physical Purpose

    NASA Astrophysics Data System (ADS)

    Arlot, J. E.; Thuillot, W.; Fienga, A.; Bec-Borsenberger, A.; Baron, N.; Berthier, J.; Colas, F.; Descamps, P.

    1999-12-01

    At the Institut de mecanique celeste-Bureau des longitudes, we started several programs of observation of the natural planetary satellites. First, we took the opportunity of the transit of the Earth and the Sun in the equatorial plane of Jupiter to observe the mutual phenomena of the Galilean satellites. These observations provide astrometric data of high accuracy useful for dynamical studies of the motions of the satellites and photometric data allowing to characterize the surfaces of the satellites. A campaign was organized leading to 400 light curves made throughout the world in about 40 countries. Second, we started astrometric CCD observations of the faint satellites of Jupiter JVI to JXIII and of the satellite of Saturn Phoebe (SIX) for dynamical purpose at Observatoire de Haute Provence using the 120cm-telescope. PPM, Hipparcos and USNO A.2 catalogue were used for calibration in order to get absolute J2000 R.A. and declination of these objects. In August and December, 1998, CCD observations provided 43 absolute positions of JVI, 23 of JVII, 53 of JVIII, 35 of JIX, 29 of JX, 27 of JXI, 18 of JXII, 16 of JXIII and 135 of SIX (Phoebe). A campaign will also take place in 1999.

  13. The results of the 2015 campaign of observation of mutual events of the Jovian satellites

    NASA Astrophysics Data System (ADS)

    Arlot, J. E.; Saquet, E.; Emelianov, N.

    2015-10-01

    From September 2014 to June 2015 mutual events of the Galilean satellites occurred around the Jovian equinox occurring on February 6, 2015. The observations of these events provide very accurate information on the relative astrometry of the satellites. Previous campaign of observations have shown the high interest of such observations now performed mainly by amateur astronomers: the Galilean satellites are bright and the magnitude drop during these events is easily observable. The 2014- 2015 campaign is especially favorable because of the maximum of events which will occur during the opposition between the Sun and Jupiter. More, eclipses of Thebe and Amalthea by the Galileans have been observed. Note that the positive declination of Jupiter made the observations easier in the Northern hemisphere where, unfortunately, the meteorological conditions were bad.

  14. Measurement of the Earth-Observer-1 Satellite X-Band Phased Array

    NASA Technical Reports Server (NTRS)

    Perko, Kenneth; Dod, Louis; Demas, John

    2003-01-01

    The recent launch and successful orbiting of the EO-1 Satellite has provided an opportunity to validate the performance of a newly developed X-Band transmit-only phased array aboard the satellite. This paper will compare results of planar near-field testing before and after spacecraft installation as well as on-orbit pattern characterization. The transmit-only array is used as a high data rate antenna for relaying scientific data from the satellite to earth stations. The antenna contains distributed solid-state amplifiers behind each antenna element that cannot be monitored except for radiation pattern measurements. A unique portable planar near-field scanner allows both radiation pattern measurements and also diagnostics of array aperture distribution before and after environmental testing over the ground-integration and prelaunch testing of the satellite. The antenna beam scanning software was confirmed from actual pattern measurements of the scanned beam positions during the spacecraft assembly testing. The scanned radiation patterns on-orbit were compared to the near-field patterns made before launch to confirm the antenna performance. The near-field measurement scanner has provided a versatile testing method for satellite high gain data-link antennas.

  15. Variability of Arctic Sea Ice as Determined from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    1999-01-01

    The compiled, quality-controlled satellite multichannel passive-microwave record of polar sea ice now spans over 18 years, from November 1978 through December 1996, and is revealing considerable information about the Arctic sea ice cover and its variability. The information includes data on ice concentrations (percent areal coverages of ice), ice extents, ice melt, ice velocities, the seasonal cycle of the ice, the interannual variability of the ice, the frequency of ice coverage, and the length of the sea ice season. The data reveal marked regional and interannual variabilities, as well as some statistically significant trends. For the north polar ice cover as a whole, maximum ice extents varied over a range of 14,700,000 - 15,900,000 sq km, while individual regions experienced much greater percent variations, for instance, with the Greenland Sea having a range of 740,000 - 1,110,000 sq km in its yearly maximum ice coverage. In spite of the large variations from year to year and region to region, overall the Arctic ice extents showed a statistically significant, 2.80% / decade negative trend over the 18.2-year period. Ice season lengths, which vary from only a few weeks near the ice margins to the full year in the large region of perennial ice coverage, also experienced interannual variability, along with spatially coherent overall trends. Linear least squares trends show the sea ice season to have lengthened in much of the Bering Sea, Baffin Bay, the Davis Strait, and the Labrador Sea, but to have shortened over a much larger area, including the Sea of Okhotsk, the Greenland Sea, the Barents Sea, and the southeastern Arctic.

  16. SatelliteDL - An IDL Toolkit for the Analysis of Satellite Earth Observations - GOES, MODIS, VIIRS and CERES

    NASA Astrophysics Data System (ADS)

    Fillmore, D. W.; Galloy, M. D.; Kindig, D.

    2013-12-01

    SatelliteDL is an IDL toolkit for the analysis of satellite Earth observations from a diverse set of platforms and sensors. The design features an abstraction layer that allows for easy inclusion of new datasets in a modular way. The core function of the toolkit is the spatial and temporal alignment of satellite swath and geostationary data. IDL has a powerful suite of statistical and visualization tools that can be used in conjunction with SatelliteDL. Our overarching objective is to create utilities that automate the mundane aspects of satellite data analysis, are extensible and maintainable, and do not place limitations on the analysis itself. Toward this end we have constructed SatelliteDL to include (1) HTML and LaTeX API document generation, (2) a unit test framework, (3) automatic message and error logs, (4) HTML and LaTeX plot and table generation, and (5) several real world examples with bundled datasets available for download. For ease of use, datasets, variables and optional workflows may be specified in a flexible format configuration file. Configuration statements may specify, for example, a region and date range, and the creation of images, plots and statistical summary tables for a long list of variables. SatelliteDL enforces data provenance; all data should be traceable and reproducible. The output NetCDF file metadata holds a complete history of the original datasets and their transformations, and a method exists to reconstruct a configuration file from this information. Release 0.1.0 of SatelliteDL is anticipated for the 2013 Fall AGU conference. It will distribute with ingest methods for GOES, MODIS, VIIRS and CERES radiance data (L1) as well as select 2D atmosphere products (L2) such as aerosol and cloud (MODIS and VIIRS) and radiant flux (CERES). Future releases will provide ingest methods for ocean and land surface products, gridded and time averaged datasets (L3 Daily, Monthly and Yearly), and support for 3D products such as temperature and

  17. Assessing the impact of end-member selection on the accuracy of satellite-based spatial variability models for actual evapotranspiration estimation

    NASA Astrophysics Data System (ADS)

    Long, Di; Singh, Vijay P.

    2013-05-01

    This study examines the impact of end-member (i.e., hot and cold extremes) selection on the performance and mechanisms of error propagation in satellite-based spatial variability models for estimating actual evapotranspiration, using the triangle, surface energy balance algorithm for land (SEBAL), and mapping evapotranspiration with high resolution and internalized calibration (METRIC) models. These models were applied to the soil moisture-atmosphere coupling experiment site in central Iowa on two Landsat Thematic Mapper/Enhanced Thematic Mapper Plus acquisition dates in 2002. Evaporative fraction (EF, defined as the ratio of latent heat flux to availability energy) estimates from the three models at field and watershed scales were examined using varying end-members. Results show that the end-members fundamentally determine the magnitudes of EF retrievals at both field and watershed scales. The hot and cold extremes exercise a similar impact on the discrepancy between the EF estimates and the ground-based measurements, i.e., given a hot (cold) extreme, the EF estimates tend to increase with increasing temperature of cold (hot) extreme, and decrease with decreasing temperature of cold (hot) extreme. The coefficient of determination between the EF estimates and the ground-based measurements depends principally on the capability of remotely sensed surface temperature (Ts) to capture EF (i.e., depending on the correlation between Ts and EF measurements), being slightly influenced by the end-members. Varying the end-members does not substantially affect the standard deviation and skewness of the EF frequency distributions from the same model at the watershed scale. However, different models generate markedly different EF frequency distributions due to differing model physics, especially the limiting edges of EF defined in the remotely sensed vegetation fraction (fc) and Ts space. In general, the end-members cannot be properly determined because (1) they do not

  18. The Galilean Satellites of Jupiter from 1610 TO 1985 - Observations and Movements

    NASA Astrophysics Data System (ADS)

    Morando, B.

    As soon as the Galilean Satellites were discovered in 1610, they have been extensively observed in order to establish tables of their motions. Visual eclipse observations were replaced by photographic observations in the XIXth century but mutual events give the best accuracy. The most important theories were Laplace's and Sampson's. New approaches will soon lead to better ephemerides.

  19. Spatiotemporal Characteristics of High-m ULF Waves Observed by ST-5 Satellites

    NASA Astrophysics Data System (ADS)

    Leinweber, H. K.; Chi, P. J.; Le, G.

    2013-12-01

    The ultra-low-frequency (ULF) waves in the inner magnetosphere with small azimuthal scale lengths, high azimuthal wavenumbers (m) have important implications in identifying the condition of wave-particle interactions. These high-m waves are invisible to ground magnetometers due to ionospheric screening, and the estimation of m using multi-satellite observations is often difficult because of the stringent requirements in satellite separation. Le et al. [2011] discovered that the Pc 2-3 waves frequently observed by the ST-5 satellites at low altitudes should be Doppler shifted Pc 5 waves with high m values. Following their first study on the high-m waves observed by ST-5, we further the analysis by estimating the wave frequency in the Earth's frame with satellite measurements and by examining how this frequency varies with L-value. The analysis is aided by the string-of-pearls configuration of the ST-5 satellites. We also compare the wave frequencies inferred from ST-5 observations with field line resonance frequencies detected by ground-based magnetometers located near the footpoints of ST-5 satellites.

  20. Magnitude Standardization Procedure for OWL-Net Optical Observations of LEO Satellites

    NASA Astrophysics Data System (ADS)

    Roh, Dong-Goo; Choi, Jin; Jo, Jung Hyun; Yim, Hong-Suh; Park, Sun-Youp; Park, Maru; Choi, Young-Jun; Bae, Young-Ho; Park, Young-Sik; Jang, Hyun-Jung; Cho, Sungki; Kim, Ji-Hye; Park, Jang-Hyun

    2015-12-01

    As a governmentally approved domestic entity for Space Situational Awareness, Korea Astronomy and Space Science Institute (KASI) is developing and operating an optical telescopes system, Optical Wide-field PatroL (OWL) Network. During the test phase of this system, it is necessary to determine the range of brightness of the observable satellites. We have defined standard magnitude for Low Earth Orbit (LEO) satellites to calibrate their luminosity in terms of standard parameters such as distance, phase angle, and angular rate. In this work, we report the optical brightness range of five LEO Satellites using OWL-Net.

  1. Determination of the orbit of the CHAMP satellite based on the laser observations

    NASA Astrophysics Data System (ADS)

    Lejba, P.

    This work presents the results of orbit determination of the CHAMP satellite from observations of 14 the best SLR stations for year 2002 All computations were based on the Earth combined gravity field model EIGEN-CG01C Reigber et al 2005 In computations was taken the orbital programme GEODYN-II created and accesibled by NASA The got RMS value of the orbit of the CHAMP satellite is better than 30 cm The obtained results show that the orbit of the CHAMP satellite is highly perturbed by the Earth s gravity field and by the atmosphere of the Earth

  2. Climate-active Trace Gases from ACE Satellite Observations

    NASA Astrophysics Data System (ADS)

    Bernath, P. F.; Brown, A.; Harrison, J.; Chipperfield, M.; Boone, C.; Wilson, C.; Walker, K. A.

    2011-12-01

    ACE (also known as SCISAT) is making a comprehensive set of simultaneous measurements of more than 30 trace gases, thin clouds, aerosols and temperature by solar occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) gives ACE coverage of tropical, mid-latitudes and polar regions. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4400 cm-1) is measuring the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. Launched by NASA in August 2003 for a nominal two-year mission, ACE performance remains excellent after 8 years in orbit. Volume mixing ratio (VMR) profiles of sixteen halogenated trace gases are routinely retrieved from ACE-FTS atmospheric spectra: CCl4, CF4, CCl3F (CFC-11), CCl2F2 (CFC-12), C2Cl3F3 (CFC-113), CH3Cl, ClONO2, COF2, COCl2, COClF, CHF2Cl (HCFC-22), CH3CCl2F (HCFC-141b), CH3CClF2 (HCFC-142b), HCl, HF and SF6. ACE also provides VMR profiles for CH4, N2O and OCS; HCFC-23 (CHF3) is a recent research product. ACE-FTS measurements were compared to surface measurements made by the AGAGE network and output from the SLIMCAT three-dimensional (3-D) chemical transport model, which is constrained by similar surface data. ACE-FTS measurements of CFCs (and HCl) show declining trends which agree with both AGAGE and SLIMCAT values. The concentrations of HCFCs are increasing with ACE-FTS, SLIMCAT and AGAGE all showing positive trends. These results illustrate the success of the Montreal Protocol in reducing ozone depleting substances. The replacement of CFCs with HCFCs has led to an increase in the VMR of HF in the stratosphere. As chlorine containing compounds continue to be phased out and replaced by fluorine-containing molecules, it is likely that total atmospheric fluorine will continue increasing in the near future. These species are all powerful greenhouse gases. ACE provides near global VMR

  3. Refractive aiming corrections for satellite observation of stars

    SciTech Connect

    Vittitoe, C.N.; Schmidt, R.L.

    1997-03-01

    Standard references describe how apparent zenith angles differ from true zenith angles for observers on the Earth. In fact, correction formulae are available for aiming Earth-based sensors at stars; some corrections give variations as a function of observer altitude. Such corrections have not been available for observers in space. This report develops formulae appropriate for proper aiming from space-based sensors toward the relatively few stars that are near the Earth`s limb at any given time. These formulae correct for refractive effects and may be critical for steerable space-borne sensors with fields of view less than one degree, tasked to observe starlight passing near the Earth`s surface. Ray tracing in the U.S. Standard Atmosphere, 1976 including H{sub 2}O effects, is used to determine relations between the refracted tangent height, the apparent tangent height resulting from observation at the sensor, and the angle through which the detected rays have deviated. Analytic fits of the ray deviation as a function of apparent tangent height allows quick determination of corrections needed for a space-borne sensor. Using those results that apply in the plane of incidence and using the necessary coordinate rotations, alterations in the star`s apparent right ascension and declination are evaluated to improve the aim. Examples illustrate that alterations can be larger than one degree, with effects lasting up to a few minutes.

  4. Estimation of Auroral Environment by Electrostatic Full-particle Simulations Modeling of REIMEI Satellite Observations

    NASA Astrophysics Data System (ADS)

    Ueda, Hiroko O.; Okada, Masaki; Usui, Hideyuki; Muranaka, Takanobu; Shinohara, Iku

    A full particle-in-cell (PIC) plasma simulator with higher accuracy as well as reasonable performance for studying spacecraft-plasma interactions has been developed. It is applied to estimate characteristics of the onboard current monitors (CRM) for a small scientific satellite REIMEI in the polar orbit, because calibration is required for the observation data. Basic characteristics in typical plasma environments including effects of the satellite geometry are demonstrated.

  5. A comparison of type III solar radio burst theories using satellite radio observations and particle measurements.

    NASA Technical Reports Server (NTRS)

    Evans, L. G.; Fainberg, J.; Stone, R. G.

    1971-01-01

    The required electron density to excite a type III solar burst can be predicted from different theories, using the low frequency radio observations of the RAE-1 satellite. Electron flux measurements by satellite in the vicinity of 1 AU then give an independent means of comparing these predicted exciter electron densities to the measured density. On this basis, one theory predicts the electron density in closest agreement with the measured values.

  6. Satellite observations of upper stratospheric and mesospheric OH: The HOxdilemma

    NASA Astrophysics Data System (ADS)

    Conway, Robert R.; Summers, Michael E.; Stevens, Michael H.; Cardon, Joel G.; Preusse, Peter; Offermann, Dirk

    2000-09-01

    We report the first observations of the vertical distribution of hydroxyl (OH) from the upper stratosphere to the mesopause. The Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) made these measurements in August 1997. The data confirm the results from the earlier November 1994 MAHRSI mission that were confined to altitudes above 50 km, namely that mesospheric OH densities are 25 to 35% lower than predicted by standard photochemical theory. However, the new observations show that below 50 km the OH density increases rapidly and at 43 km altitude it is larger than that expected from standard theory. This represents a serious dilemma for our understanding of odd-hydrogen chemistry because the same key reactions are thought to dominate OH/HO2 partitioning in both regions. We show that neither standard photochemical theory nor any previously proposed changes are adequate to explain the OH observations in both the upper stratosphere and mesosphere.

  7. Multiple satellite observations of leakage of particles from the magnetosphere

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.; Mcentire, R. W.

    1988-01-01

    The properties of four potential sources for energetic ions and electrons in the magnetosheath are considered: upstream Fermi acceleration and shock drift acceleration of incident solar wind particles at the bow shock, acceleration of magnetosheath ions through merging at the magnetopause, and escape from the magnetosphere. A review of previous observations suggests that the magnetosphere is the dominant source of the magnetosheath energetic particle population. Despite recent work to the contrary, it is questioned whether energetic particle observations alone provide any evidence for merging at the dayside magnetopause.

  8. Comparison of cloud properties observed from in situ and satellite measurements

    NASA Astrophysics Data System (ADS)

    Noble, S. R.; Hudson, J. G.

    2013-12-01

    Climate is influenced by clouds reflecting radiation. Adjustments in cloud properties occur with changes to the cloud environment such as changes in aerosol or vertical velocity. These adjustments change the cloud radiative forcing. Three ways exist to study cloud properties: in situ observations, satellite observations, and modeling of cloud properties. Data sets from in situ measurements in field campaigns such as Physics of Stratocumulus Top (POST) (Hudson et al. 2010; Hudson and Noble 2013) provide good resolution of local cloud properties but are not extensive over time or globally. Satellites provide data coverage on a global scale and over long times but at infrequent periods locally. Uncertainties arise between these two methods when attempting to understand cloud properties and effects on radiative forcing. To understand these uncertainties, we compared MODIS data to vertical cloud pass data from the POST field campaign. Data from 9 in situ slant passes were compared to data from 9 satellite passes on 8 days. Figure 1 shows these comparisons of effective radius (re) (black) and cloud optical depth (COD) (red). COD from the satellite passes compares well with in situ data near the 1:1 line. The correlation coefficient (R) for COD is 0.95 with a slope (k) of 1.05. However, re is not near the 1:1 line and shows a steep k of 2.36, which suggests an over-prediction by the satellite observations, while R is only 0.57. Satellite re compared better to maximum in situ re which yielded a flatter k of 1.44 but an R of 0.59. Maximum re occurred a few meters below stratus cloud top that may suggest larger droplets dominate over cloud thickness in satellite observations. The satellite also over-predicts liquid water path (LWP, not shown) with a k of 1.42 and an R of 0.90. Because satellite re is over-predicting, calculations of environmental precursors become more difficult. However, COD is more related to albedo and observations compare well, which appears to validate

  9. Observations of the Galilean satellites of Jupiter with Pulkovo Normal Astrograph during 2009-2011

    NASA Astrophysics Data System (ADS)

    Narizhnaya, N. V.

    2015-11-01

    The paper presents the results of observations of Jupiter and its Galilean moons, performed with the Normal Astrograph ( D/ F=0.33 m/3.5 m, CCD S2C, FOV 18' × 16') at Pulkovo observatory during 2009-2011. We obtained 140 positions of the Galilean satellites and 42 calculated positions of Jupiter in the system of UCAC4 (ICRS, J2000.0) catalogue. The equatorial coordinates of satellites have been compared to eight most current theories of planetary and satellite motion. The average residuals between the observed and calculated coordinates (O-C) using the selected theories of motion do not exceed 0.08″. The behavior and magnitudes of the (O-C) residuals in the positions of Ganymede and Callisto satellites show that the theory of their motion was elaborated worse than in the case of Io and Europa satellites. Distribution of the (O-C) residuals for Callisto differs from a normal distribution. Comparison of the calculated equatorial coordinates of Jupiter, based on the observed positions of satellites and their theoretical Jovi-centric coordinates calculated using the INPOP10 theory of planetary motion revealed satisfactory results. The average residuals are, respectively, (O-C)α = 0.040″ and (O-C)δ =-0.053″ assuming the normal distribution law.

  10. Opportunities for Coordinated Observations of CO2 with the Orbiting Carbon Observatory (OCO) and Greenhouse Gases Observing Satellite (GOSAT)

    NASA Technical Reports Server (NTRS)

    Crisp, David

    2008-01-01

    The Orbiting Carbon Observatory (OCO) and the Greenhouse Gases Observing Satellite (GOSAT) are the first two satellites designed to make global measurements of atmospheric carbon dioxide (CO2) with the precision and sampling needed identify and monitor surface sources and sinks of this important greenhouse gas. Because the operational phases of the OCO and GOSAT missions overlap in time, there are numerous opportunities for comparing and combining the data from these two satellites to improve our understanding of the natural processes and human activities that control the atmospheric CO2 and it variability over time. Opportunities for cross-calibration, cross-validation, and coordinated observations that are currently under consideration are summarized here.

  11. Obs4MIPS: Satellite Observations for Model Evaluation

    NASA Astrophysics Data System (ADS)

    Ferraro, R.; Waliser, D. E.; Gleckler, P. J.

    2015-12-01

    This poster will review the current status of the obs4MIPs project, whose purpose is to provide a limited collection of well-established and documented datasets for comparison with Earth system models (https://www.earthsystemcog.org/projects/obs4mips/). These datasets have been reformatted to correspond with the CMIP5 model output requirements, and include technical documentation specifically targeted for their use in model output evaluation. There are currently over 50 datasets containing observations that directly correspond to CMIP5 model output variables. We will review recent additions to the obs4MIPs collection, and provide updated download statistics. We will also provide an update on changes to submission and documentation guidelines, the work of the WCRP Data Advisory Council (WDAC) Observations for Model Evaluation Task Team, and engagement with the CMIP6 MIP experiments.

  12. Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.; Hashimoto, Kozo; Boardsen, Scott A.; Garcia, Leonard N.; Green, James L.; Matsumoto, Hiroshi; Reinisch, Bodo W.

    2010-01-01

    We report IMAGE and Geotail simultaneous observations of a terrestrial myriametric radio burst (TMRB) detected on August 19, 2001. The TMRB was confined in time (0830-1006 UT) and frequency (12-50 kHz), suggesting a fan beam-like emission pattern from a single discrete source. Analysis and comparisons with existing TMR radiations strongly suggest that the TMRB is a distinct emission perhaps resulting from dayside magnetic reconnection instigated by northward interplanetary field condition.

  13. A satellite observation test bed for cloud parameterization development

    NASA Astrophysics Data System (ADS)

    Lebsock, M. D.; Suselj, K.

    2015-12-01

    We present an observational test-bed of cloud and precipitation properties derived from CloudSat, CALIPSO, and the the A-Train. The focus of the test-bed is on marine boundary layer clouds including stratocumulus and cumulus and the transition between these cloud regimes. Test-bed properties include the cloud cover and three dimensional cloud fraction along with the cloud water path and precipitation water content, and associated radiative fluxes. We also include the subgrid scale distribution of cloud and precipitation, and radiaitive quantities, which must be diagnosed by a model parameterization. The test-bed further includes meterological variables from the Modern Era Retrospective-analysis for Research and Applications (MERRA). MERRA variables provide the initialization and forcing datasets to run a parameterization in Single Column Model (SCM) mode. We show comparisons of an Eddy-Diffusivity/Mass-FLux (EDMF) parameterization coupled to micorphsycis and macrophysics packages run in SCM mode with observed clouds. Comparsions are performed regionally in areas of climatological subsidence as well stratified by dynamical and thermodynamical variables. Comparisons demonstrate the ability of the EDMF model to capture the observed transitions between subtropical stratocumulus and cumulus cloud regimes.

  14. Satellite observations of stratospheric hydrogen fluoride and comparisons with SLIMCAT calculations

    NASA Astrophysics Data System (ADS)

    Harrison, J. J.; Chipperfield, M. P.; Boone, C. D.; Dhomse, S. S.; Bernath, P. F.; Froidevaux, L.; Anderson, J.; Russell, J., III

    2015-12-01

    The vast majority of emissions of fluorine-containing molecules are anthropogenic in nature, e.g. chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). Many of these fluorine-containing species deplete stratospheric ozone, and are regulated by the Montreal Protocol. Once in the atmosphere they slowly degrade, ultimately leading to the formation of HF, the dominant reservoir of stratospheric fluorine due to its extreme stability. Monitoring the growth of stratospheric HF is therefore an important marker for the success of the Montreal Protocol. We report the comparison of global distributions and trends of HF measured in the Earth's atmosphere by the satellite remote-sensing instruments ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer), which has been recording atmospheric spectra since 2004, and HALOE (HALogen Occultation Experiment), which recorded atmospheric spectra between 1991 and 2005, with the output of SLIMCAT, a state-of-the-art three-dimensional chemical transport model. In general the agreement between observation and model is good, although the ACE-FTS measurements are biased high by ∼ 10 % relative to HALOE. The observed global HF trends reveal a substantial slowing down in the rate of increase of HF since the 1990s: 4.97 ± 0.12 % year-1 (1991-1997; HALOE), 1.12 ± 0.08 % year-1 (1998-2005; HALOE), and 0.52 ± 0.03 % year-1 (2004-2012; ACE-FTS). In comparison, SLIMCAT calculates trends of 4.01, 1.10, and 0.48 % year-1, respectively, for the same periods; the agreement is very good for all but the earlier of the two HALOE periods. Furthermore, the observations reveal variations in the HF trends with latitude and altitude, for example between 2004 and 2012 HF actually decreased in the Southern Hemisphere below ∼ 35 km. SLIMCAT calculations broadly agree with these observations, most notably between 2004 and 2012. Such variations are attributed to variability in stratospheric dynamics

  15. Satellite observations of stratospheric hydrogen fluoride and comparisons with SLIMCAT calculations

    NASA Astrophysics Data System (ADS)

    Harrison, Jeremy J.; Chipperfield, Martyn P.; Boone, Christopher D.; Dhomse, Sandip S.; Bernath, Peter F.; Froidevaux, Lucien; Anderson, John; Russell, James, III

    2016-08-01

    The vast majority of emissions of fluorine-containing molecules are anthropogenic in nature, e.g. chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). Many of these fluorine-containing species deplete stratospheric ozone and are regulated by the Montreal Protocol. Once in the atmosphere they slowly degrade, ultimately leading to the formation of hydrogen fluoride (HF), the dominant reservoir of stratospheric fluorine due to its extreme stability. Monitoring the growth of stratospheric HF is therefore an important marker for the success of the Montreal Protocol. We report the comparison of global distributions and trends of HF measured in the Earth's atmosphere by the satellite remote-sensing instruments ACE-FTS (Atmospheric Chemistry Experiment Fourier transform spectrometer), which has been recording atmospheric spectra since 2004, and HALOE (HALogen Occultation Experiment), which recorded atmospheric spectra between 1991 and 2005, with the output of SLIMCAT, a state-of-the-art three-dimensional chemical transport model. In general the agreement between observation and model is good, although the ACE-FTS measurements are biased high by ˜ 10 % relative to HALOE. The observed global HF trends reveal a substantial slowing down in the rate of increase of HF since the 1990s: 4.97 ± 0.12 % year-1 (1991-1997; HALOE), 1.12 ± 0.08 % year-1 (1998-2005; HALOE), and 0.52 ± 0.03 % year-1 (2004-2012; ACE-FTS). In comparison, SLIMCAT calculates trends of 4.01, 1.10, and 0.48 % year-1, respectively, for the same periods; the agreement is very good for all but the earlier of the two HALOE periods. Furthermore, the observations reveal variations in the HF trends with latitude and altitude; for example, between 2004 and 2012 HF actually decreased in the Southern Hemisphere below ˜ 35 km. An additional SLIMCAT simulation with repeating meteorology for the year 2000 produces much cleaner trends in HF with minimal variations with latitude

  16. Satellite Observations of New Volcanic Island in Tonga

    NASA Technical Reports Server (NTRS)

    Vaughan, R. Greg; Abrams, Michael J.; Hook, Simon J.; Pieri, David C.

    2007-01-01

    A rising volcanic plume from an unknown source was observed on 9-11 August 2006 in the Vava'u Island group in the northernmost islands of Tonga [Matangi News Online, 2006]. On 12 August, the crew on board the yacht Maiken, sailing west from Vava'u to Fiji, encountered 'a vast, many miles wide, belt of densely packed pumice' floating on the water (F. Fransson personal communication, 2006). Later, the crew sailed south and discovered that the source of the pumice was a newly erupting submarine volcano near Home Reef (18.991 deg S, 174.767 deg W).

  17. CME-Associated Radio Bursts from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Gopalswamy, Nat

    2012-01-01

    Coronal mass ejections (CMEs) are closely associated with various types of radio bursts from the Sun. All radio bursts are due to nonthermal electrons, which are accelerated during the eruption of CMEs. Radio bursts at frequencies below about 15 MHz are of particular interest because they are associated with energetic CMEs that contribute to severe space weather. The low-frequency bursts need to be observed primarily from space because of the ionospheric cutoff. The main CME-related radio bursts are associated are: type III bursts due to accelerated electrons propagating along open magnetic field lines, type II bursts due to electrons accelerated in shocks, and type IV bursts due to electrons trapped in post-eruption arcades behind CMEs. This paper presents a summary of results obtained during solar cycle 23 primarily using the white-light coronagraphic observations from the Solar Heliospheric Observatory (SOHO) and the WAVES experiment on board Wind. Particular emphasis will be placed on what we can learn about particle acceleration in the coronal and interplanetary medium by analyzing the CMEs and the associated radio bursts.

  18. Real Time Monitoring of Flooding from Microwave Satellite Observations

    NASA Technical Reports Server (NTRS)

    Galantowicz, John F.; Frey, Herb (Technical Monitor)

    2002-01-01

    We have developed a new method for making high-resolution flood extent maps (e.g., at the 30-100 m scale of digital elevation models) in real-time from low-resolution (20-70 km) passive microwave observations. The method builds a "flood-potential" database from elevations and historic flood imagery and uses it to create a flood-extent map consistent with the observed open water fraction. Microwave radiometric measurements are useful for flood monitoring because they sense surface water in clear-or-cloudy conditions and can provide more timely data (e.g., compared to radars) from relatively wide swath widths and an increasing number of available platforms (DMSP, ADEOS-II, Terra, NPOESS, GPM). The chief disadvantages for flood mapping are the radiometers' low resolution and the need for local calibration of the relationship between radiances and open-water fraction. We present our method for transforming microwave sensor-scale open water fraction estimates into high-resolution flood extent maps and describe 30-day flood map sequences generated during a retrospective study of the 1993 Great Midwest Flood. We discuss the method's potential improvement through as yet unimplemented algorithm enhancements and expected advancements in microwave radiometry (e.g., improved resolution and atmospheric correction).

  19. VLBI observations of GNSS satellites on the baseline Hobart-Ceduna

    NASA Astrophysics Data System (ADS)

    Hellerschmied, Andreas; Böhm, Johannes; Kwak, Younghee; McCallum, Jamie; Plank, Lucia

    2016-04-01

    Observations of satellites of Global Navigation Satellite Systems (GNSS) with the geodetic Very Long Baseline Interferometry (VLBI) technique open a variety of new possibilities and promote the integration of these techniques within the framework of GGOS, the Global Geodetic Observing System of the IAG. Such observations provide possibilities to directly connect the dynamic GNSS and the kinematic VLBI reference frame, which may result in improved future ITRF realizations. In our research we are trying to apply observation strategies, which are commonly used in geodetic VLBI, i.e. the main observables are group delay values derived from direct observations and the subsequent correlations of GNSS satellite signals. However, data acquisition schemes for VLBI satellite observations are still at an experimental stage. Further research is required to establish an operational process chain, similar to that applied for natural radio sources, such as quasars, which are observed generally. In 2015 we successfully carried out several experiments on the Australian baseline Ceduna-Hobart. During these sessions, with a few hours duration each, GNSS satellites (GLONASS and GPS) were observed in the L1 and L2 band along with natural radio sources for calibrations. All experiments were based on schedule files created with the satellite scheduling module in the Vienna VLBI Software (VieVS). The recorded data were successfully correlated with the DiFX correlator software in combination with a suitable input model for near field targets. A preliminary analysis of the group delay measurements derived with the AIPS software suite was carried out with VieVS. Using this workflow we can achieve a measurement precision of the group delays down to a few picoseconds (5-30, depending on the satellite) over a 5 minutes track. Nevertheless, our results also show a residual signal of a few nanoseconds, which might be caused by the ionosphere or insufficient orbit modelling in the present state of

  20. Applications of neural network methods to the processing of earth observation satellite data.

    PubMed

    Loyola, Diego G

    2006-03-01

    The new generation of earth observation satellites carries advanced sensors that will gather very precise data for studying the Earth system and global climate. This paper shows that neural network methods can be successfully used for solving forward and inverse remote sensing problems, providing both accurate and fast solutions. Two examples of multi-neural network systems for the determination of cloud properties and for the retrieval of total columns of ozone using satellite data are presented. The developed algorithms based on multi-neural network are currently being used for the operational processing of European atmospheric satellite sensors and will play a key role in related satellite missions planed for the near future.

  1. Astrometric observations of the faint satellites of Jupiter during the 1975 - 1976 opposition

    NASA Technical Reports Server (NTRS)

    Mulholland, J. D.; Shelus, P. J.; Benedict, G. F.

    1979-01-01

    The series of astrometric observations of the satellites of the trans-martian planets re-established at the McDonald Observatory in 1972 is continued. The positions deduced from photographic observations of the jovian system obtained during the 1975-76 opposition are presented together with the discovery positions of four asteroids found on these plates.

  2. Satellite Observations: Oil Spills Impact on Phytoplankton in Bohai Sea

    NASA Astrophysics Data System (ADS)

    Zhou, Li; Tang, Danling; Wang, Sufen; Pan, Gang

    2014-11-01

    This study discussed ecological responses to the Penglai oil spills in the Bohai Sea, occurring on June 4, 2011, using MODIS Chlorophyll-a data. After time intervals of 20 days, 12 months and 14 months, phytoplankton blooms appeared at three locations in the surrounding and distant regions of the oil spills in the Bohai Sea. A bloom with high Chlorophyll-a (13.66 mg m-3) spread over an area of 800 km2 on June 18-25, 2011, about 56 km northeast from the location of the oil spills. A pronounced increase in the monthly Chlorophyll-a concentration (6.40 mg m-3) indicating phytoplankton bloom was observed in the Bohai Sea in June 2012. Phytoplankton blooms depend on the amount and composition of oil, toxicity of petroleum hydrocarbons, micro-organisms, and sea ice. The oil spills impact phytoplankton for a long duration, which impacts the marine ecosystem.

  3. Land surface water cycles observed with satellite sensors

    NASA Technical Reports Server (NTRS)

    Nghiem, Son V.; Njoku, E. G.; Brakenridge, G. R.; Kim, Y.

    2005-01-01

    Acceleration of the global water cycle may lead to increased global precipitation, faster evaporation and a consequent exacerbation of hydrologic extreme. In the U.S. national assessment of the potential consequences of climate variability and change, two GCMs (CGCM1 and HadCM2) show a large increase in precipitation in the future over the southwestern U.S. particularly during winter (Felzer and Heard, 1999). Increased precipitation potentially has important impacts on agricultural and water use in the southeast U.S. (Hatch et al., 1999) and in the central Great Plains (Nielsen, 1997). A hurricane model predicts a 40% precipitation increase for severe hurricanes affecting southeastern Florida, which provokes substantially greater flooding that could negate most of the benefits of present water-management practices in this basin (Gutowski et al., 1994). Thus, it is important to observe the hydroclimate on a continuous longterm basis to address the question of increased precipitation in the enhanced water cycle.

  4. Surface moisture and satellite microwave observations in semiarid southern Africa

    SciTech Connect

    Owe, M.; Chang, A.T.C. ); Van de Griend, A.A. )

    1992-03-01

    Nimbus 7 scanning multichannel microwave radiometer 6.6-GHz passive microwave data were studied in relation to large-scale soil moisture estimates over a 3-year period in southeastern Bostwana. An extensive data base of weekly surface soil moisture measurements was used with meteorological data to estimate pixel average soil moisture on a daily basis. The influence of the vegetation canopy on the surface emissivity was studied by partitioning the data set into classes on the basis of the normalized difference vegetation index. After correcting for the vegetation optical depth, a correlation of r = 0.84 was established between the normalized brightness temperature observations and surface soil moisture for the 3-year period.

  5. Stereoscopic observations of hurricanes and tornadic thunderstorms from geosynchronous satellites

    NASA Technical Reports Server (NTRS)

    Mack, R.; Hasler, A. F.; Rodgers, E. B.

    1982-01-01

    Results are presented which show the application of GOES stereoscopy to the investigation of hurricanes and tornadic thunderstorms. Stereo cloud top height contour maps were constructed to observe the structural evolution of two hurricanes, Frederic on September 12, 1979 and Allen on August 8, 1980, and a tornadic thunderstorm complex over Oklahoma on May 2-3, 1979. Stereo height contours of Hurricane Allen reveal a very intense and symmetric storm with a circular shaped central dense overcast with an average height of 16.5 km. Contours of Hurricane Frederic reveal a preferred region for convection with an explosive exhaust tower attaining a maximum height of 17.8 km. Also presented is a technique for estimating tropical cyclone intensity using GOES stereo height and IR temperature information. Results indicate vertical motions ranging from 4.4 m/s for a moderate storm to 7.7 m/s for an intense storm.

  6. Monitoring water quality from LANDSAT. [satellite observation of Virginia

    NASA Technical Reports Server (NTRS)

    Barker, J. L.

    1975-01-01

    Water quality monitoring possibilities from LANDSAT were demonstrated both for direct readings of reflectances from the water and indirect monitoring of changes in use of land surrounding Swift Creek Reservoir in a joint project with the Virginia State Water Control Board and NASA. Film products were shown to have insufficient resolution and all work was done by digitally processing computer compatible tapes. Land cover maps of the 18,000 hectare Swift Creek Reservoir watershed, prepared for two dates in 1974, are shown. A significant decrease in the pine cover was observed in a 740 hectare construction site within the watershed. A measure of the accuracy of classification was obtained by comparing the LANDSAT results with visual classification at five sites on a U-2 photograph. Such changes in land cover can alert personnel to watch for potential changes in water quality.

  7. Using Active Satellite Observations to Characterize Uncertatinty in Long Term Satellite Cloud Liquid Water Path Climatologies

    NASA Astrophysics Data System (ADS)

    Lebsock, M. D.

    2014-12-01

    Bias between the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) version 2 and the Moderate Resolution Imaging Spectroradiometer (MODIS) collection 5.1 cloud liquid water path (Wc)products are explored with the aid of coincident active observations from the CloudSat radar and the CALIPSO lidar. In terms of detection, the active observations provide precise separation of cloudy from clear sky and precipitating from nonprecipitating clouds. In addition, they offer a unique quantification of precipitation water path (Wp) in warm clouds. They also provide an independent quantification of Wc that isbased on an accurate surface reference technique, which is an independent arbiter between the two passive approaches. The results herein establish the potential for CloudSat and CALIPSO to provide an independent assessment of bias between the conventional passive remote sensing methods from reflected solar and emitted microwave radiation. After applying a common data filter to the observations to account for sampling biases, AMSR-E is biased high relative to MODIS in the global mean by 26.4gm2. The RMS difference in the regional patterns is 32.4gm2, which highlights a large geographical dependence in the bias which is related to the tropical transitions from stratocumulus to cumulus cloud regimes. The contributions of four potential sources for this bias are investigated by exploiting the active observations: (1)bias in MODIS related to solar zenith angle dependence accounts for 2.3gm2, (2) bias in MODIS due to undersampling of cloud edges accounts for 4.2gm2, (3) a wind speed and water vapor-dependent "clear-sky bias" in the AMSR-E retrieval accounts for 6.3gm2, and (4) evidence suggests that much of the remaining 18gm2 bias is related to the assumed partitioning of the observed emission signal between cloud and precipitation water in the AMSR-E retrieval. This is most evident through the correlations between the regional mean patterns of Wp and the Wc bias within the

  8. Estimation of gross primary production capacity from global satellite observations

    NASA Astrophysics Data System (ADS)

    Muramatsu, Kanako; Thanyapraneedkul, Juthasinee; Furumi, Shinobu; Soyama, Noriko; Daigo, Motomasa

    2012-10-01

    To estimate gross primary production (GPP), the process of photosynthesis was considered as two separate phases: capacity and reduction. The reduction phase is influenced by environmental conditions such as soil moisture and weather conditions such as vapor pressure differences. For a particular leaf, photosynthetic capacity mainly depends on the amount of chlorophyll and the RuBisCO enzyme. The chlorophyll content can be estimated by the color of the leaf, and leaf color can be detected by optical sensors. We used the chlorophyll content of leaves to estimate the level of GPP. A previously developed framework for GPP capacity estimation employs a chlorophyll index. The index is based on the linear relationship between the chlorophyll content of a leaf and the maximum photosynthesis at PAR =2000 (μmolm -2s-1) on a light-response curve under low stress conditions. As a first step, this study examined the global distribution of the index and found that regions with high chlorophyll index values in winter corresponded to tropical rainforest areas. The seasonal changes in the chlorophyll index differed from those shown by the normalized difference vegetation index. Next, the capacity of GPP was estimated from the light-response curve using the index. Most regions exhibited a higher GPP capacity than that estimated from Moderate Resolution Imaging Spectroradiometer (MODIS) observations, except in areas of tropical rainforest, where the GPP capacity and the MODIS GPP estimates were almost identical.

  9. Regional Satellite Observations for Dryland Degradation Studies (Invited)

    NASA Astrophysics Data System (ADS)

    Prince, S. D.

    2009-12-01

    The lack of global scale maps of degraded drylands remains a significant obstacle to identification, prevention and mitigation of desertification. To fill this gap, maps are needed that have some or all of the following characteristics. i Use quantitative variables that have defined biogeophysical meaning. ii Identify areas that are currently in a state of desertification as well as showing areas having higher risk of degradation. iii Provide a synopsis of the condition of land over a number of years, not only a single point in time. iv Repeatable, using consistent observations and an explicit methodology, with a clear link to methods for monitoring and change detection. v Flexible enough to allow adaptation to regional needs while not compromising the ability to compare regions on the basis of consistent criteria. vi At a scale adequate to identify the normal spatial scales of desertification - sub-national, but greater than individual land holdings. vii Down-scalable to allow the specific factors and processes responsible for degradation in a specific location to be identified. viii Can be used as state variables in household-scale studies. ix Up-scalable to allow impacts on processes such as climate change that are relevant at a coarse spatial resolution. x Presented in a data base with appropriate additional maps, such as topography, land use, soil properties, and rainfall, to allow interpretation. xi Can be validated and have information on potential error. xii Not reliant on a single data source nor on a single institution.

  10. Multiple Satellite Observations of Cloud Cover in Extratropical Cyclones

    NASA Technical Reports Server (NTRS)

    Naud, Catherine M.; Booth, James F.; Posselt, Derek J.; van den Heever, Susan C.

    2013-01-01

    Using cloud observations from NASA Moderate Resolution Imaging Spectroradiometer, Multiangle Imaging Spectroradiometer, and CloudSat-CALIPSO, composites of cloud fraction in southern and northern hemisphere extratropical cyclones are obtained for cold and warm seasons between 2006 and 2010, to assess differences between these three data sets, and between summer and winter cyclones. In both hemispheres and seasons, over the open ocean, the cyclone-centered cloud fraction composites agree within 5% across the three data sets, but behind the cold fronts, or over sea ice and land, the differences are much larger. To supplement the data set comparison and learn more about the cyclones, we also examine the differences in cloud fraction between cold and warm season for each data set. The difference in cloud fraction between cold and warm season southern hemisphere cyclones is small for all three data sets, but of the same order of magnitude as the differences between the data sets. The cold-warm season contrast in northern hemisphere cyclone cloud fractions is similar for all three data sets: in the warm sector, the cold season cloud fractions are lower close to the low, but larger on the equator edge than their warm season counterparts. This seasonal contrast in cloud fraction within the cyclones warm sector seems to be related to the seasonal differences in moisture flux within the cyclones. Our analysis suggests that the three different data sets can all be used confidently when studying the warm sector and warm frontal zone of extratropical cyclones but caution should be exerted when studying clouds in the cold sector.

  11. Constraining the low-cloud optical depth feedback at middle and high latitudes using satellite observations

    DOE PAGES

    Terai, C. R.; Klein, S. A.; Zelinka, M. D.

    2016-08-26

    The increase in cloud optical depth with warming at middle and high latitudes is a robust cloud feedback response found across all climate models. This study builds on results that suggest the optical depth response to temperature is timescale invariant for low-level clouds. The timescale invariance allows one to use satellite observations to constrain the models' optical depth feedbacks. Three passive-sensor satellite retrievals are compared against simulations from eight models from the Atmosphere Model Intercomparison Project (AMIP) of the 5th Coupled Model Intercomparison Project (CMIP5). This study confirms that the low-cloud optical depth response is timescale invariant in the AMIPmore » simulations, generally at latitudes higher than 40°. Compared to satellite estimates, most models overestimate the increase in optical depth with warming at the monthly and interannual timescales. Many models also do not capture the increase in optical depth with estimated inversion strength that is found in all three satellite observations and in previous studies. The discrepancy between models and satellites exists in both hemispheres and in most months of the year. A simple replacement of the models' optical depth sensitivities with the satellites' sensitivities reduces the negative shortwave cloud feedback by at least 50% in the 40°–70°S latitude band and by at least 65% in the 40°–70°N latitude band. Furthermore, based on this analysis of satellite observations, we conclude that the low-cloud optical depth feedback at middle and high latitudes is likely too negative in climate models.« less

  12. Tropospheric Aerosol Climate Forcing in Clear-Sky Satellite Observations over the Oceans.

    PubMed

    Haywood; Ramaswamy; Soden

    1999-02-26

    Tropospheric aerosols affect the radiative forcing of Earth's climate, but their variable concentrations complicate an understanding of their global influence. Model-based estimates of aerosol distributions helped reveal spatial patterns indicative of the presence of tropospheric aerosols in the satellite-observed clear-sky solar radiation budget over the world's oceans. The results show that, although geographical signatures due to both natural and anthropogenic aerosols are manifest in the satellite observations, the naturally occurring sea-salt is the leading aerosol contributor to the global-mean clear-sky radiation balance over oceans. PMID:10037595

  13. Estimation of evaporation over the upper Blue Nile basin by combining observations from satellites and river flow gauges

    NASA Astrophysics Data System (ADS)

    Allam, Mariam M.; Jain Figueroa, Anjuli; McLaughlin, Dennis B.; Eltahir, Elfatih A. B.

    2016-02-01

    Reliable estimates of regional evapotranspiration are necessary to improve water resources management and planning. However, direct measurements of evaporation are expensive and difficult to obtain. Some of the difficulties are illustrated in a comparison of several satellite-based estimates of evapotranspiration for the Upper Blue Nile (UBN) basin in Ethiopia. These estimates disagree both temporally and spatially. All the available data products underestimate evapotranspiration leading to basin-scale mass balance errors on the order of 35 percent of the mean annual rainfall. This paper presents a methodology that combines satellite observations of rainfall, terrestrial water storage as well as river-flow gauge measurements to estimate actual evapotranspiration over the UBN basin. The estimates derived from these inputs are constrained using a one-layer soil water balance and routing model. Our results describe physically consistent long-term spatial and temporal distributions of key hydrologic variables, including rainfall, evapotranspiration, and river-flow. We estimate an annual evapotranspiration over the UBN basin of about 2.55 mm per day. Spatial and temporal evapotranspiration trends are revealed by dividing the basin into smaller subbasins. The methodology described here is applicable to other basins with limited observational coverage that are facing similar future challenges of water scarcity and climate change.

  14. Using Satellite Observations to Infer the Relationship Between Cold Pools and Subsequent Convection Development

    NASA Technical Reports Server (NTRS)

    Elsaesser, Gregory

    2015-01-01

    Cold pools are increasingly being recognized as important players in the evolution of both shallow and deep convection; hence, the incorporation of cold pool processes into a number of recently developed convective parameterizations. Unfortunately, observations serving to inform cold pool parameterization development are limited to select field programs and limited radar domains. However, a number of recent studies have noted that cold pools are often associated with arcs-lines of shallow clouds traversing 10 100 km in visible satellite imagery. Boundary layer thermodynamic perturbations are plausible at such scales, coincident with such mesoscale features. Atmospheric signatures of features at these spatial scales are potentially observable from satellites. In this presentation, we discuss recent work that uses multi-sensor, high-resolution satellite products for observing mesoscale wind vector fluctuations and boundary layer temperature depressions attributed to cold pools produced by antecedent convection. The relationship to subsequent convection as well as convective system longevity is discussed. As improvements in satellite technology occur and efforts to reduce noise in high-resolution orbital products progress, satellite pixel level (10 km) thermodynamic and dynamic (e.g. mesoscale convergence) parameters can increasingly serve as useful benchmarks for constraining convective parameterization development, including for regimes where organized convection contributes substantially to the cloud and rainfall climatology.

  15. Neural Networks Technique for Filling Gaps in Satellite Measurements: Application to Ocean Color Observations.

    PubMed

    Krasnopolsky, Vladimir; Nadiga, Sudhir; Mehra, Avichal; Bayler, Eric; Behringer, David

    2016-01-01

    A neural network (NN) technique to fill gaps in satellite data is introduced, linking satellite-derived fields of interest with other satellites and in situ physical observations. Satellite-derived "ocean color" (OC) data are used in this study because OC variability is primarily driven by biological processes related and correlated in complex, nonlinear relationships with the physical processes of the upper ocean. Specifically, ocean color chlorophyll-a fields from NOAA's operational Visible Imaging Infrared Radiometer Suite (VIIRS) are used, as well as NOAA and NASA ocean surface and upper-ocean observations employed--signatures of upper-ocean dynamics. An NN transfer function is trained, using global data for two years (2012 and 2013), and tested on independent data for 2014. To reduce the impact of noise in the data and to calculate a stable NN Jacobian for sensitivity studies, an ensemble of NNs with different weights is constructed and compared with a single NN. The impact of the NN training period on the NN's generalization ability is evaluated. The NN technique provides an accurate and computationally cheap method for filling in gaps in satellite ocean color observation fields and time series.

  16. Field observations of the relation between satellite and sea radiances in coastal waters

    NASA Astrophysics Data System (ADS)

    Aas, Eyvind; Sørensen, Kai

    1995-08-01

    Estimates of the different contributions to the satellite radiance above the outer Oslofjord are presented. The contribution from the sea is of the order of 10% of the total signal, and the part due to reflection from the sea surface constitutes 10-20%. The presence of land may increase the satellite radiance up to 4-9%, but such effects, which are probably reduced to 1/e at a distance of 1 km from the coast, cannot be detected in the present measurements. In situ observations of the marine radiance are corrected for shadings by ship and instrument and for varying solar altitude. The average correction for the self-shading effect of the marine instrument becomes 30-50% in these waters. The linear relations between satellite and sea radiances are determined with correlation coefficients of better than 0.95. The observed minimum value of the satellite radiance (or darkest pixel) is not a satisfactory approximation for the atmospheric correction. It is concluded that, in coastal waters and at the present stage, satellite observations have to be combined with field measurements to obtain reliable results.

  17. Neural Networks Technique for Filling Gaps in Satellite Measurements: Application to Ocean Color Observations

    PubMed Central

    Nadiga, Sudhir; Mehra, Avichal; Bayler, Eric; Behringer, David

    2016-01-01

    A neural network (NN) technique to fill gaps in satellite data is introduced, linking satellite-derived fields of interest with other satellites and in situ physical observations. Satellite-derived “ocean color” (OC) data are used in this study because OC variability is primarily driven by biological processes related and correlated in complex, nonlinear relationships with the physical processes of the upper ocean. Specifically, ocean color chlorophyll-a fields from NOAA's operational Visible Imaging Infrared Radiometer Suite (VIIRS) are used, as well as NOAA and NASA ocean surface and upper-ocean observations employed—signatures of upper-ocean dynamics. An NN transfer function is trained, using global data for two years (2012 and 2013), and tested on independent data for 2014. To reduce the impact of noise in the data and to calculate a stable NN Jacobian for sensitivity studies, an ensemble of NNs with different weights is constructed and compared with a single NN. The impact of the NN training period on the NN's generalization ability is evaluated. The NN technique provides an accurate and computationally cheap method for filling in gaps in satellite ocean color observation fields and time series. PMID:26819586

  18. Snow Water Equivalent estimation based on satellite observation

    NASA Astrophysics Data System (ADS)

    Macchiavello, G.; Pesce, F.; Boni, G.; Gabellani, S.

    2009-09-01

    forest canopy density. Finally, the SWE has to be calculated for the snow covered areas, detected by means of a previously developed decision tree classifier able to classify snow cover by self selecting rules in a statistically optimum way. The advantages introduced from this work are many. Firstly, applying a suitable method with data features, it is possible to automatically obtain snow cover description with high frequency. Moreover, the advantages of the modularity in the proposed approach allows to improve the three factors estimation in an independent way. Limitations lie into clouds problem that affects results by obscuring the observed territory, that is bounded by fusing temporal and spatial information. Then the spatial resolution of data, satisfactory with the scale of hydrological models, mismatch with the available in situ point information, causing difficulties for a method validation or calibration. However this working flow results computationally cost-effectiveness, robust to the radiometric noise of the original data, provides spatially extended and frequent information.

  19. Analysis of L5 phase variations in GPS IIF satellites by the raw observation PPP approach

    NASA Astrophysics Data System (ADS)

    Liu, Sha; Becker, Matthias

    2015-04-01

    GPS modernization along with Glonass modernization and the emerging Galileo and Compass system has been highly anticipated by every GNSS user since several years. The third civilian L5 signal transmitted by the modernized GPS satellites brings us to the GNSS multi-frequency era. The first GPS IIF satellite was launched in May 2010, until now there are eight block IIF satellites in service and the remaining four IIF satellites are planned to be launched by 2016. The introduction of the third frequency to GPS and the usage of advanced atomic clocks not only provide the users more possibilities but also enable higher positioning accuracy. Nevertheless phase variations are found on the new L5 observation of GPS SVN62. Further investigations suggest that the variations of this satellite are strongly dependent on the satellite inner temperature variation caused by sun illumination. Besides achieving precise positioning accuracy, PPP is also frequently used as a tool to analyze and evaluate various GNSS errors, for instance, tropospheric delays and receiver clock errors. Other than with differential GNSS, it is possible to separate different errors and to identify the error sources with PPP. Conventional PPP is based on the ionosphere-free linear combination, in order to eliminate the first-order ionospheric delays. However only dual frequencies can be used to build ionosphere-free linear combination, which leads to the waste of the information on the third frequency. Furthermore, the frequency dependent errors can not be separated and traced. A new PPP approach that avoids using any linear combination is proposed recently, which is called the raw observation PPP. One advantage of the raw observation PPP approach is that data of all frequencies and all GNSS systems can be jointly used. In addition, the frequency dependent errors are possible to be separated, identified and analyzed. In this paper the raw observation PPP is utilized to analyze the phase variations on L5

  20. Who launched what, when and why; trends in global land-cover observation capacity from civilian earth observation satellites

    NASA Astrophysics Data System (ADS)

    Belward, Alan S.; Skøien, Jon O.

    2015-05-01

    This paper presents a compendium of satellites under civilian and/or commercial control with the potential to gather global land-cover observations. From this we show that a growing number of sovereign states are acquiring capacity for space based land-cover observations and show how geopolitical patterns of ownership are changing. We discuss how the number of satellites flying at any time has progressed as a function of increased launch rates and mission longevity, and how the spatial resolutions of the data they collect has evolved. The first such satellite was launched by the USA in 1972. Since then government and/or private entities in 33 other sovereign states and geopolitical groups have chosen to finance such missions and 197 individual satellites with a global land-cover observing capacity have been successfully launched. Of these 98 were still operating at the end of 2013. Since the 1970s the number of such missions failing within 3 years of launch has dropped from around 60% to less than 20%, the average operational life of a mission has almost tripled, increasing from 3.3 years in the 1970s to 8.6 years (and still lengthening), the average number of satellites launched per-year/per-decade has increased from 2 to 12 and spatial resolution increased from around 80 m to less than 1 m multispectral and less than half a meter for panchromatic; synthetic aperture radar resolution has also fallen, from 25 m in the 1970s to 1 m post 2007. More people in more countries have access to data from global land-cover observing spaceborne missions at a greater range of spatial resolutions than ever before. We provide a compendium of such missions, analyze the changes and shows how innovation, the need for secure data-supply, national pride, falling costs and technological advances may underpin the trends we document.

  1. Low-power magnetometer observation with satellite data transmission at unmanned site in Antarctica

    NASA Astrophysics Data System (ADS)

    Yamagishi, H.; Kadokura, A.

    2012-12-01

    We will report technical experiences from 6 years of unmanned low power magnetometer observation in Antarctica with daily data transmission via Iridium satellite telephone link. One of the difficulties of unmanned observation in Antarctica is dark winter months in which power supply from solar panel can not be expected. One solution for this difficulty is to minimize the power consumption (as small as ~1 W) to manage the observation in winter months with limited amount of batteries (~400Ah). Another difficulty is to collect data from the observation site. It is quite expensive and laborious to send a party to the observation site to obtain the data in Antarctica. Although cost for satellite communication is expensive, it is much more economical to collect data via satellite data link by installing a telephone terminal into the observation system. It seems that power consumption of a satellite phone (~10 W) does not fit to the low power system. However, as long as the observed data is not too large (<1 Mbyte per day), turn on period of the satellite phone is short (<1 hour per day) and the daily average of total power consumption lies within the available power of ~1 W. We have developed low-power magnetometer system with Iridium satellite phone data link. Basic design of the low-power system is similar to that developed by British Antarctic Survey (intermittent operation of magnetometer and GPS). However, we have made some improvements; reduced power consumption (0.2 W) at high sampling rate (1Hz) and increased sensitivity (0.2nT), so that geomagnetic pulsation study can be possible. In our observation system, satellite data transfer is only made in sunlit season with the total power consumption of 1 W (0.8W for Iridium phone and 0.2W for others). During dark winter months, observed data are stored in CF memory with diminished power consumption of 0.2W. When the sun comes in spring, the stored data are transmitted along with the daily observed data. It takes nearly

  2. Astrometry of natural satellites: improving the dynamics of Mars, Jupiter and Saturn with old observations

    NASA Astrophysics Data System (ADS)

    Robert, Vincent; Pascu, Dan; Lainey, Valéry; Arlot, Jean-Eudes

    2014-11-01

    A new astrometric reduction of old photographic plates, benefiting from modern technologies such as sub-micrometric scanners associated with a reduction using accurate catalogues (UCAC at the present time and GAIA in a near future), provides improved knowledge of the orbital motion of planetary satellites.In the framework of an international collaboration first, and in the FP7 ESPaCE european project afterward, U.S. Naval Observatory plates were digitized with the new generation DAMIAN scanning machine of the Royal Observatory of Belgium. The procedure was applied to a few hundred photographic plates of the Martian satellites covering the years 1967-1997, of the Galilean satellites covering the years 1967-1998, and of the major Saturnian satellites covering the years 1974-1998. We provide results with an accuracy better than 60 mas in (RA,Dec) positions of the Martian satellites, better than 70 mas in (RA,Dec) positions of the Galilean moons, and better than 100 mas in (RA,Dec) positions of the major Saturnian moons. Since the positions of the planets may be deduced from the observed (RA,Dec) positions of their satellites, we can also assess the accuracy of the ephemerides of Mars, Jupiter and Saturn.

  3. Multi-technique combination of space geodesy observations: Impact of the Jason-2 satellite on the GPS satellite orbits estimation

    NASA Astrophysics Data System (ADS)

    Zoulida, Myriam; Pollet, Arnaud; Coulot, David; Perosanz, Félix; Loyer, Sylvain; Biancale, Richard; Rebischung, Paul

    2016-10-01

    In order to improve the Precise Orbit Determination (POD) of the GPS constellation and the Jason-2 Low Earth Orbiter (LEO), we carry out a simultaneous estimation of GPS satellite orbits along with Jason-2 orbits, using GINS software. Along with GPS station observations, we use Jason-2 GPS, SLR and DORIS observations, over a data span of 6 months (28/05/2011-03/12/2011). We use the Geophysical Data Records-D (GDR-D) orbit estimation standards for the Jason-2 satellite. A GPS-only solution is computed as well, where only the GPS station observations are used. It appears that adding the LEO GPS observations results in an increase of about 0.7% of ambiguities fixed, with respect to the GPS-only solution. The resulting GPS orbits from both solutions are of equivalent quality, agreeing with each other at about 7 mm on Root Mean Square (RMS). Comparisons of the resulting GPS orbits to the International GNSS Service (IGS) final orbits show the same level of agreement for both the GPS-only orbits, at 1.38 cm in RMS, and the GPS + Jason2 orbits at 1.33 cm in RMS. We also compare the resulting Jason-2 orbits with the 3-technique Segment Sol multi-missions d'ALTimétrie, d'orbitographie et de localisation précise (SSALTO) POD products. The orbits show good agreement, with 2.02 cm of orbit differences global RMS, and 0.98 cm of orbit differences RMS on the radial component.

  4. Remote observing with the Keck Telescope from California using NASA's ACTS satellite

    NASA Astrophysics Data System (ADS)

    Shopbell, Patrick L.; Cohen, Judith G.; Bergman, Larry A.

    1997-09-01

    As a technical demonstration project for the NASA Advanced Communications Technology Satellite (ACTS), we have implemented remote observing on the 10-meter Keck II telescope on Mauna Kea in Hawaii from the California Institute of Technology campus in Pasadena. The data connection consists of ATM networks in Hawaii and California, running at OC-1 speeds (51 Mbit/sec) through optical fiber, and high data rate (HDR) satellite antennae at JPL in Pasadena and at the Tripler Army Medical Center in Honolulu. The ACTS network provides sufficient bandwidth to enable true remote observing, with a software environment identical to that used for on-site observing. In this paper, we demonstrate that while the satellite link introduces a number of difficulties and decreases overall reliability of the system, remote observing is not only feasible, but provides several important advantages over standard observing paradigms. Benefits include involving more members of observing teams while decreasing expenses, enhancing real-time data analysis of observations by persons not subject to altitude-related conditions, and providing facilities, expertise, and personnel not normally available at the observing site. Although the current bandwidth of the public Internet is insufficient for true remote observing, we nevertheless anticipate a growing role for remote observing techniques, particularly as high-speed terrestrial networking paradigms, such as ATM, become more commonly available.

  5. Observing the earth radiation budget from satellites - Past, present, and a look to the future

    NASA Technical Reports Server (NTRS)

    House, F. B.

    1985-01-01

    Satellite measurements of the radiative exchange between the planet earth and space have been the objective of many experiments since the beginning of the space age in the late 1950's. The on-going mission of the Earth Radiation Budget (ERB) experiments has been and will be to consider flight hardware, data handling and scientific analysis methods in a single design strategy. Research and development on observational data has produced an analysis model of errors associated with ERB measurement systems on polar satellites. Results show that the variability of reflected solar radiation from changing meteorology dominates measurement uncertainties. As an application, model calculations demonstrate that measurement requirements for the verification of climate models may be satisfied with observations from one polar satellite, provided there is information on diurnal variations of the radiation budget from the ERBE mission.

  6. Evaluation of satellite soil moisture products over Norway using ground-based observations

    NASA Astrophysics Data System (ADS)

    Griesfeller, A.; Lahoz, W. A.; Jeu, R. A. M. de; Dorigo, W.; Haugen, L. E.; Svendby, T. M.; Wagner, W.

    2016-03-01

    In this study we evaluate satellite soil moisture products from the advanced SCATterometer (ASCAT) and the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) over Norway using ground-based observations from the Norwegian water resources and energy directorate. The ASCAT data are produced using the change detection approach of Wagner et al. (1999), and the AMSR-E data are produced using the VUA-NASA algorithm (Owe et al., 2001, 2008). Although satellite and ground-based soil moisture data for Norway have been available for several years, hitherto, such an evaluation has not been performed. This is partly because satellite measurements of soil moisture over Norway are complicated owing to the presence of snow, ice, water bodies, orography, rocks, and a very high coastline-to-area ratio. This work extends the European areas over which satellite soil moisture is validated to the Nordic regions. Owing to the challenging conditions for soil moisture measurements over Norway, the work described in this paper provides a stringent test of the capabilities of satellite sensors to measure soil moisture remotely. We show that the satellite and in situ data agree well, with averaged correlation (R) values of 0.72 and 0.68 for ASCAT descending and ascending data vs in situ data, and 0.64 and 0.52 for AMSR-E descending and ascending data vs in situ data for the summer/autumn season (1 June-15 October), over a period of 3 years (2009-2011). This level of agreement indicates that, generally, the ASCAT and AMSR-E soil moisture products over Norway have high quality, and would be useful for various applications, including land surface monitoring, weather forecasting, hydrological modelling, and climate studies. The increasing emphasis on coupled approaches to study the earth system, including the interactions between the land surface and the atmosphere, will benefit from the availability of validated and improved soil moisture satellite datasets, including those

  7. PHEMU 2003 campaign: observations of the mutual phenomena of the Galilean satellites in Romania

    NASA Astrophysics Data System (ADS)

    Arlot, J.-E.; Chis, G.-D.; Farkas, L.; Moldovan, D.; Nedelcu, A.; Popescu, P.; Sorescu, S.; Stavinschi, M.; Serbanescu, L.; Tudose, V.; Turcu, V.

    2005-08-01

    We present CCD, photoelectric, and video observations of selected mutual phenomena of the Galilean satellites. The campaign was carried out in Bucharest and Cluj-Napoca as part of the PHEMU2003 international effort. Five different optical systems were used for data acquisition. Here we report the observational results obtained in acceptable meteorological conditions for twenty mutual phenomena, nine eclipses, and eleven occultations. A preliminary analysis of the observations estimates the accuracy of the data.

  8. Satellite observations support to disaster monitoring: the operational use of COSMO-SkyMed constellation

    NASA Astrophysics Data System (ADS)

    Candela, Laura; Cardaci, Chiara; Coletta, Alessandro; Corina, Angela; Di Bucci, Daniela; Giuliani, Roberta; Pagliara, Paola; Zoffoli, Simona; Boni, Giorgio

    2013-04-01

    The aim of this work is to show some experiences recently made by ASI and DPC, with the collaboration of Italian research institutes and academies, in using satellite observations to monitor different steps of emergency management in Italy: the 2012 Emilia earthquakes and the 2012 seismic sequence in the Mt. Pollino area, the volcano Stromboli eruption, the floods occurred in Tuscany and Lazio. The effectiveness of the satellite observations contribution to the disaster management is to day in phase of demonstration, and the encouraging results obtained up to now rely not only on the maturity of the data processing and interpretation techniques (more exploited), but also on the coordination in accessing and programming satellites systems. During the past year, COSMO-SkyMed has been successfully used to acquire, in very short times, high quality images of disaster areas. When the emergency evolution made it necessary, after the set up the monitoring service went on several months. Our experience confirmed how important is the availability of consistent series of satellite data, acquired on disaster prone areas in order to enable and facilitate post-disaster activities. Moreover, some results have been made possible thanks to science oriented initiatives sponsored by ASI and to the long-lasting cooperation among DPC and the national research institutions. In general, to meet civil protection needs after a disaster, typical activities based on earth observation techniques, as rapid mapping, recovery and first evaluation of damage, require the following observation capabilities: • medium-to-high spatial resolution • high revisit time, coupled with large spatial and spectral coverage • night/daylight and all-weather observations • capability of very short response time and frequent revisit opportunities for the study area • availability of a good reference archive • access and provision of satellite data for operational purposes, based on well defined rules

  9. High resolution earth observation satellites and services in the next decade a European perspective

    NASA Astrophysics Data System (ADS)

    Schreier, Gunter; Dech, Stefan

    2005-07-01

    Projects to use very high resolution optical satellite sensor data started in the late 90s and are believed to be the major driver for the commercialisation of earth observation. The global political security situation and updated legislative frameworks created new opportunities for high resolution, dual use satellite systems. In addition to new optical sensors, very high resolution synthetic aperture radars will become in the next few years an important component in the imaging satellite fleet. The paper will review the development in this domain so far, and give perspectives on future emerging markets and opportunities. With dual-use satellite initiatives and new political frameworks agreed between the European Commission and the European Space Agency (ESA), the European market becomes very attractive for both service suppliers and customers. The political focus on "Global Monitoring for Environment and Security" (GMES) and the "European Defence and Security Policy" drive and amplify this demand which ranges from low resolution climate monitoring to very high resolution reconnaissance tasks. In order to create an operational and sustainable GMES in Europe by 2007, the European infrastructure need to be adapted and extended. This includes the ESA SENTINEL and OXYGEN programmes, aiming for a fleet of earth observation satellites and an open and operational earth observation ground segment. The harmonisation of national and regional geographic information is driven by the European Commission's INSPIRE programme. The necessary satellite capacity to complement existing systems in the delivery of space based data required for GMES is currently under definition. Embedded in a market with global competition and in the global political framework of a Global Earth Observation System of Systems, European companies, agencies and research institutions are now contributing to this joint undertaking. The paper addresses the chances, risks and options for the future.

  10. Role of light satellites in the high-resolution Earth observation domain

    NASA Astrophysics Data System (ADS)

    Fishman, Moshe

    1999-12-01

    Current 'classic' applications using and exploring space based earth imagery are exclusive, narrow niche tailored, expensive and hardly accessible. On the other side new, inexpensive and widely used 'consumable' applications will be only developed concurrently to the availability of appropriate imagery allowing that process. A part of these applications can be imagined today, like WWW based 'virtual tourism' or news media, but the history of technological, cultural and entertainment evolution teaches us that most of future applications are unpredictable -- they emerge together with the platforms enabling their appearance. The only thing, which can be ultimately stated, is that the definitive condition for such applications is the availability of the proper imagery platform providing low cost, high resolution, large area, quick response, simple accessibility and quick dissemination of the raw picture. This platform is a constellation of Earth Observation satellites. Up to 1995 the Space Based High Resolution Earth Observation Domain was dominated by heavy, super-expensive and very inflexible birds. The launch of Israeli OFEQ-3 Satellite by MBT Division of Israel Aircraft Industries (IAI) marked the entrance to new era of light, smart and cheap Low Earth Orbited Imaging satellites. The Earth Resource Observation System (EROS) initiated by West Indian Space, is based on OFEQ class Satellites design and it is capable to gather visual data of Earth Surface both at high resolution and large image capacity. The main attributes, derived from its compact design, low weight and sophisticated logic and which convert the EROS Satellite to valuable and productive system, are discussed. The major advantages of Light Satellites in High Resolution Earth Observation Domain are presented and WIS guidelines featuring the next generation of LEO Imaging Systems are included.

  11. Determining volcanic SO2 plume heights in satellite observations using meteorological wind fields

    NASA Astrophysics Data System (ADS)

    Keicher, Viktoria; Hörmann, Christoph; Sihler, Holger; Platt, Ulrich; Wagner, Thomas

    2016-04-01

    Satellite observations nowadays provide the global monitoring of volcanic plumes via sulphur dioxide (SO2) that is injected into the Earth's atmosphere. In turn, SO2 may lead to the formation of sulphate aerosols that can influence climate via direct and indirect radiative effects. The retrieval of SO2 requires an accurate plume height estimate in order to constrain total amounts for such events. One of the main difficulties for the retrieval is the typically unknown atmospheric profile resulting from unknown initial conditions (individual explosions over an extended time period leading to different gas layer altitudes and influencing the atmospheric transport pattern). In recent years, satellite observations helped to improve global SO2 estimates, but still large uncertainties exist. Passive satellite remote sensing using measurements in the UV/vis spectral range for example offers the opportunity to observe the location of a plume in two dimensions, but information about the corresponding height is sparse. Furthermore, information about these plume profiles is not only interesting in itself (e.g. to assess the radiative effect of volcanic plumes). It is also important for the quantitative interpretation of satellite observations. Here, we present first results for a newly developed approach using the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) in combination with data for different volcanic SO2 plumes as observed by the second generation Global Ozone Monitoring Instrument (GOME-2). The main plume information that can be retrieved by the satellite (i.e. plume location and observation time) are used as initial input parameters in order to estimate the plume's profile at the time of the measurements. For selected case studies we use these trajectories to further estimate values the eruption time and height. The correspondingly modelled values can also be used to verify the results when they are compared to direct local observations and

  12. Effective Utilization of Satellite Observations for Assessing Transnational Impact of Disasters

    NASA Astrophysics Data System (ADS)

    Alozie, J. E.; Anuforom, A. C.

    2014-12-01

    General meteorological observations sources for the surface, upper air and outer space are conducted using different technological equipment and instruments that meet international standards prescribed and approved by the United Nations organizations such as the International Civil Aviation Organization (ICAO) and the World Meteorological Organization (WMO). Satellite weather observations are critical for effective monitoring of the developments, propagations and disseminations of cold clouds and their expected adverse weather conditions as they move across national and transnational boundaries. The Nigerian Meteorological Agency (NiMet) which is the national weather service provider for Nigeria, utilizes an array of satellite products obtained from mainly the European Meteorological Satellite (EUMETSAT) for its routine weather and climate monitoring and forecasts. Overtime, NiMet has used weather workstations such as MSG, SYNERGIE and now PUMA for accessing satellite products such as RGB, Infra-red, Water vapour and the Multi-sensor Precipitation Estimate (MPE) obtained at near real-time periods. The satellite imageries find extensive applications in the delivery of early warning of raising of severe weather conditions such as dust storm and dust haze during the harmattan season (November - February); and thunderstorm accompanied by severe lightning and destructive strong winds. The paper will showcase some special cases of the tracking of squall lines and issuance of weather alerts through the media. The good result is that there was limited damage to infrastructure and no loss of life from the flash floods caused by the heavy rainfall from the squally thunderstorm.

  13. Characterizing Open Ocean Ecosystems Using Satellite Observations: Beyond the Remote Assessment of Chlorophyll

    NASA Astrophysics Data System (ADS)

    Siegel, D. A.

    2009-05-01

    Satellite observations have brought a new vantage for characterizing open ocean ecosystems on local to global spatial scales and from intraseasonal to interannual time scales. These satellite observations are most often used to assess the time/space distribution of the chlorophyll concentration, the primary photosynthetic pigment found in all phytoplankton. However, there are additional optically active constituents regulating the color of the open ocean besides chlorophyll. Here, we use novel satellite retrieval algorithms to partition the ocean color spectrum into three primary optically active constituents - the phytoplankton chlorophyll concentration (Chl), the absorption due to chromophoric dissolved organic matter (CDOM) and the particulate backscatter coefficient (BBP). We assess the variability and co-variability of these three optical properties on regional to global scales and evaluate the potential processes controlling these variations. We conclude that the chlorophyll concentration is the worst of the three primary bio-optical properties for characterizing ocean ecosystems. This is because of the extreme plastic nature of cellular chlorophyll concentrations in response to light and nutrient conditions and the difficulty in separating light absorption in phytoplankton Chl concentrations from CDOM. I suggest that future satellite missions consider the primary optically active constituents in the open ocean and provide a path for their robust determination. In this way we can maximize the scientific returns from our satellite infrastructure investments.

  14. JAXA's G-Portal Approach to Global Observation Satellite Big Data

    NASA Astrophysics Data System (ADS)

    Ikehata, Y.

    2015-12-01

    JAXA released "G-Portal" as a portal web site for search and deliver data of Earth observation satellite in February 2013. G-Portal handles ten satellites data; GPM, TRMM, Aqua, ADEOS-II, ALOS(search only), ALOS-2 (search only), MOS-1, MOS-1b, ERS-1 and JERS-1. G-Portal provides over 5.17 million products and the number of catalogues is over 14 million. Currently, G-Portal receives processed satellites data without any time lag and users can search and download in a timely manner. In the future, G-Portal will not be able to respond same as now because data size and varietieswill increase. (Observational data and variety of satellites will grow significantly) Satellites which will be scheduled to launch in the coming years will create 660,000 products and distribute 7.6TB in a day. Even in such a situation, G-Portal must provide same performance to user for searching and distribution. This paper will provide how the G-Portal will evolve to support the Big data

  15. Solar irradiance observed on the FY-3 satellites - instrument overview and primary observation results of in-orbit experiments

    NASA Astrophysics Data System (ADS)

    Wang, H.; Fang, W.; Li, H.

    2015-12-01

    Solar driving mechanism for Earth climate has been a controversial problem for centuries. Data of Solar Irradiance (SI) is required by the investigations of the solar driving mechanism, including Total Solar Irradiance (TSI) and Spectral Solar Irradiance (SSI). SI observations with short term accuracy and long term precision are essential to separate solar forcing from human-induced factors. TSI and SSI have been measured on Chinese FY-3 satellites, including FY-3A, FY-3B and FY-3C. FY-3A satellite launched in May, 2008 is the first satellite. FY-3B satellite launched in November, 2010 is the second satellite and FY-3C satellite launched in September, 2013 is the third satellite. SSI has been measured by SBUS (Solar Backscatter Ultraviolet Sounder) in the ultraviolet spectrum in the FY-3 mission. When a solar diffuser plate is deployed to reflect the incoming sunlight, SI is measured at 12 discrete, 1.1 nm wide wavelength bands between 250 nm and 340 nm. The SSI measurements are performed using a double monochromator operated in a stepped wavelength scan mode. SBUS collects SSI weekly at 12 discrete wave-lengths near polar area. Moreover, SSI is measured by SBUS every month covering 160-400 nm continuous spectral region. SSI has been recorded in SBUS missions since the ascending phase of Solar Cycle 24. Approximately the same variation tendencies of SSI were detected by SBUS in specific spectrum compared with data from SOLSTICE/SORCE. TSI have been recorded by Total Solar Irradiance Monitors (TSIM) in FY-3 missions. The sun was measured by TSIM/FY-3A and TSIM/FY-3B in a scanning manner. TSI data quality is improved by TSIM/FY-3C which has a pointing system. TSIM/FY-3C measures the sun with nearly zero solar pointing errors. TSI variations detected by TSIM/FY-3C are nearly the same with VIRGO/SOHO and TIM/SORCE. The TSIM experiments have observed the sun for about 7 years. A slowly increasing TSI trend has been detected by TSIMs in the Solar Cycle 24. We present the

  16. Astrometric CCD observations of the inner Jovian satellites in 1999-2000

    NASA Astrophysics Data System (ADS)

    Kulyk, I.; Jockers, K.; Karpov, N.; Sergeev, A.

    2002-02-01

    This paper presents the results of observations of the inner Jovian satellites Thebe, Amalthea, Adrastea and Metis made in October-November 1999 and in November 2000. We provide Delta alpha and Delta delta of Thebe and Amalthea with respect to the Galilean satellites, while the positions of Adrastea and Metis are referred to either the Galilean moons or to Thebe or to Amalthea. All observed positions are compared with theoretical ones. Residual statistics show an inner accuracy of our observations in the range from about 0.1 to 0.9 arcsec. The dependence of the differences of the observed and calculated positions on the orbital longitude is presented for our observations of Adrastea and Metis.

  17. The PHESAT95 catalogue of observations of the mutual events of the Saturnian satellites

    NASA Astrophysics Data System (ADS)

    Thuillot, W.; Arlot, J.-E.; Ruatti, C.; Berthier, J.; Blanco, C.; Colas, F.; Czech, W.; Damani, M.; D'Ambrosio, V.; Descamps, P.; Dourneau, G.; Emelianov, N.; Foglia, S.; Helmer, G.; Irsmambetova, T. R.; James, N.; Laques, P.; Lecacheux, J.; Le Campion, J.-F.; Ledoux, C.; Le Floch, J.-C.; Oprescu, G.; Rapaport, M.; Riccioli, R.; Starosta, B.; Tejfel, V. G.; Trunkovsky, E. M.; Viateau, B.; Veiga, C. H.; Vu, D. T.

    2001-05-01

    In 1994-1996 the Sun and the Earth passed through the equatorial plane of Saturn and therefore through the orbital planes of its main satellites. During this period, phenomena involving seven of these satellites were observed. Light curves of eclipses by Saturn and of mutual eclipses and occultations were recorded by the observers of the international campaign PHESAT95 organized by the Institut de mécanique céleste, Paris, France. Herein, we report 66 observations of 43 mutual events from 16 sites. For each observation, information is given about the telescope, the receptor, the site and the observational conditions. This paper gathers together all these data and gives a first estimate of the precision providing accurate astrometric data useful for the development of dynamical models.

  18. Satellite observation and mapping of wintertime ozone variability in the lower stratosphere

    NASA Technical Reports Server (NTRS)

    Geller, M. A.; Chi, Yuechen; Rood, R. B.; Douglass, A. R.; Kaye, J. A.; Allen, D. J.

    1993-01-01

    Comparison is made between 30 mbar ozone fields that are generated by a transport chemistry model utilizing the winds from the Goddard Space Flight Center stratospheric data assimilation system (STRATAN), observations from the LIMS instrument on Nimbus-7, and the ozone fields that result from 'flying' a mathematical simulation of LIMS observations through the transport chemistry model ozone fields. The modeled ozone fields were found to resemble the LIMS observations, but the model fields show much more temporal and spatial structure than do the LIMS observations. The 'satellite mapped' model results resemble the LIMS observations much more closely. These results are very consistent with the earlier discussions of satellite space-time sampling by Salby.

  19. Assimilation of Coarse-Scale Satellite Soil Moisture Observations into a Fine-Scale Hydrologic Model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has been demonstrated that passive microwave observations from space are capable of mapping surface soil moisture over the globe. Currently, the Advanced Microwave Scanning Radiometer (AMSR-E) onboard NASA’s Aqua satellite is providing moisture content in the top 1~2 cm of the soil column, and fu...

  20. Assimilation of coarse-scale satellite soil moisture observations into a fine-scale hydrologic model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has been demonstrated that passive microwave observations from space are capable of mapping surface soil moisture over the globe. Currently, the Advanced Microwave Scanning Radiometer (AMSR-E) onboard NASA’s Aqua satellite is providing moisture content in the top 1~2 cm of the soil column, and f...

  1. Satellite scheduling considering maximum observation coverage time and minimum orbital transfer fuel cost

    NASA Astrophysics Data System (ADS)

    Zhu, Kai-Jian; Li, Jun-Feng; Baoyin, He-Xi

    2010-01-01

    In case of an emergency like the Wenchuan earthquake, it is impossible to observe a given target on earth by immediately launching new satellites. There is an urgent need for efficient satellite scheduling within a limited time period, so we must find a way to reasonably utilize the existing satellites to rapidly image the affected area during a short time period. Generally, the main consideration in orbit design is satellite coverage with the subsatellite nadir point as a standard of reference. Two factors must be taken into consideration simultaneously in orbit design, i.e., the maximum observation coverage time and the minimum orbital transfer fuel cost. The local time of visiting the given observation sites must satisfy the solar radiation requirement. When calculating the operational orbit elements as optimal parameters to be evaluated, we obtain the minimum objective function by comparing the results derived from the primer vector theory with those derived from the Hohmann transfer because the operational orbit for observing the disaster area with impulse maneuvers is considered in this paper. The primer vector theory is utilized to optimize the transfer trajectory with three impulses and the Hohmann transfer is utilized for coplanar and small inclination of non-coplanar cases. Finally, we applied this method in a simulation of the rescue mission at Wenchuan city. The results of optimizing orbit design with a hybrid PSO and DE algorithm show that the primer vector and Hohmann transfer theory proved to be effective methods for multi-object orbit optimization.

  2. Spectroscopic observations of the Uranus' satellite Miranda in Near-IR

    NASA Astrophysics Data System (ADS)

    Gourgeot, F.; Dumas, C.; Merlin, F.; Vernazza, P.; Alvarez-Candal, A.

    2013-09-01

    We present new Near-IR spectra of the Uranus' icy satellite Miranda. This body is probably the most remarkable of all satellites of Uranus, displaying series of surface features such as faults, craters and largescale upwelling, remnant of a geologically very active past. The observations were performed first at the Palomar Observatory with the PHARO instrument (Palomar High Angular Resolution Observer) and then at the Mauna Kea Observatory with SpeX instrument based on the IRTF (Infra-Red Telescope Facility). Water ice is clearly visible in K-band (large 2.0 μm absorption band) and crystalline water ice (at 1.65 μm) seems to cover the most part of the satellite's surface. We focused the study in H band on the 1.42-1.72 μm range at observations dates corresponding to the leading and trailing hemispheres of Miranda. Contrary to the other outer Uranus' moons (Grundy et al. 2006), we did not found any significative differences between both hemispheres in this spectral range. We also studied the possible presence of volatiles like ammonia hydrate and do not exclude the possible presence of a tiny 2.22 μm band yet observed by Bauer et al. 2002. No significant features of carbon dioxide were identified on any spectra. We performed spectral models, based on bi-hemispherical reflectance theory (Hapke 1993) in order to obtain more details on the chemical compounds possibly present on the surface of this Uranian satellite.

  3. Observations of the global structure of the stratosphere and mesosphere with sounding rockets and with remote sensing techniques from satellites

    NASA Technical Reports Server (NTRS)

    Heath, D. F.; Hilsenrath, E.; Krueger, A. J.; Nordberg, W.; Prabhakara, C.; Theon, J. S.

    1972-01-01

    Brief descriptions are given of the techniques involved in determining the global structure of the mesosphere and stratosphere based on sounding rocket observations and satellite remotely sensed measurements.

  4. Astrometric observations of planets, minor planets, and satellites - 1976-1980

    NASA Astrophysics Data System (ADS)

    Klemola, A. R.

    1981-07-01

    Equatorial coordinates for Uranus, Neptune, several minor planets, and the Jovian satellites were measured between 1976 and 1980. All observations were made with the yellow lens of the 0.51 m Carnegie double astrograph for the purpose of refining the predictions of stellar occultations. After 1977 the astrometric reduction program for equatorial coordinates included the option for precorrection of measurements for higher order terms, and other than Jupiter II, positions of Jovian satellites for 1980 December 09.56840 and 12.56285 were made by means of manual and automatic machine measurements.

  5. Assessing the impact of satellite-based observations in sea surface temperature trends

    NASA Astrophysics Data System (ADS)

    Huang, Boyin; Liu, Chunying; Banzon, Viva F.; Zhang, Huai-Min; Karl, Thomas R.; Lawrimore, Jay H.; Vose, Russell S.

    2016-04-01

    Global trends of sea surface temperature (SST) are assessed for the existing and new experimental SST analyses that incorporate advanced very high resolution radiometer (AVHRR) observations from NOAA polar-orbiting satellites. These analyses show that globally and annually averaged SST trends over the 21st century (2000-2015) are similar to the trends for the full satellite record period (1982-2015), regardless of whether AVHRR data are included in the analyses. It is shown that appropriate bias correction is an important step to remove discontinuities of AVHRR data for consistent time series and trend analysis.

  6. Candidate configuration trade study, Stellar-inertial Measurement Systems (SIMS) for an Earth Observation Satellite (EOS)

    NASA Technical Reports Server (NTRS)

    Ogletree, G.; Coccoli, J.; Mckern, R.; Smith, M.; White, R.

    1972-01-01

    The results of analytical and simulation studies of the stellar-inertial measurement system (SIMS) for an earth observation satellite are presented. Subsystem design analyses and sensor design trades are reported. Three candidate systems are considered: (1) structure-mounted gyros with structure-mounted star mapper, (2) structure-mounted gyros with gimbaled star tracker, and (3) gimbaled gyros with structure-mounted star mapper. The purpose of the study is to facilitate the decisions pertaining to gimbaled versus structure-mounted gyros and star sensors, and combinations of systems suitable for the EOS satellite.

  7. Scaling Issues Between Plot and Satellite Radiobrightness Observations of Arctic Tundra

    NASA Technical Reports Server (NTRS)

    Kim, Edward J.; England, Anthony W.; Judge, Jasmeet; Zukor, Dorothy J. (Technical Monitor)

    2000-01-01

    Data from generation of satellite microwave radiometer will allow the detection of seasonal to decadal changes in the arctic hydrology cycle as expressed in temporal and spatial patterns of moisture stored in soil and snow This nw capability will require calibrated Land Surface Process/Radiobrightness (LSP/R) model for the principal terrains found in the circumpolar Arctic. These LSP/R models can than be used in weak constraint. Dimensional Data Assimilation (DDA)of the daily satellite observation to estimate temperature and moisture profiles within the permafrost in active layer.

  8. Real-time, Quasi-Global, Multi-Satellite Precipitation Analysis Using TRMM and other Satellite Observations

    NASA Technical Reports Server (NTRS)

    Adler, Robert F.; Huffman, George; Curtis, Scott; Bolvin, David; Nelkin, Eric

    2003-01-01

    A TRMM-based 3-hr analyses that use TRMM observations to calibrate polar-orbit microwave observations from SSM/I (and other satellites) and geosynchronous IR observations and merges the various calibrated observations into a final, 3-hr resolution map is described. This TRMM standard product will be available for the entire TRMM period (January 1998-present) in 2003 as part of Version 6 of the TRMM products. A real-time version of this merged product is being produced and is available at 0.25" latitude-longitude resolution over the latitude range from 50 N-500S. Examples will be shown, including its use in monitoring flood conditions and in relating weather-scale patterns to climate-scale patterns. Plans to incorporate the TRMM data and 3-hourly analysis into the Global Precipitation Climatology Project (GPCP) products are outlined. The outcome in the near future should be an improved global analysis and climatology on monthly scales for the 23 year period and finer time scale analyses for more recent periods, including 3-hourly analyses over the globe. These technique developments are potential prototypes for analyses with the Global Precipitation Measurement (GPM) mission.

  9. Estimates of surface ultraviolet radiation over north America using Geostationary Operational Environmental Satellites observations

    NASA Astrophysics Data System (ADS)

    Gadhavi, H.; Pinker, R. T.; Laszlo, I.

    2008-11-01

    Information on ultraviolet (UV) radiative fluxes is needed for public safety, understanding biodiversity, and for chemical transport modeling. Space-based observations can provide homogeneous and systematic estimates of the UV flux over large regions. In the past, UV flux estimates have been made from polar orbiting satellites; such estimates lack information on diurnal variability that can result in significant errors in UV dose (diurnally integrated UV flux). An algorithm has been developed to estimate diurnally varying spectral UV flux at the surface based on information from geostationary satellites (cloud amount, surface albedo and aerosols) and from polar orbiting satellites (ozone). Algorithm evaluation is done by comparison with ground-based observations made between January 1998 and December 2000 over eighteen stations of the United States Department of Agriculture (USDA)'s UV monitoring network. A good agreement between ground-based observations and satellite estimates is found with a mean bias (satellite - ground) of +3.5% for all-sky (cloudy + clear) cases. A negative mean bias of the same magnitude is found for clear-sky cases. Root mean square (RMS) differences are 25% and 14% for all-sky and clear-sky cases, respectively. Using simulations, it is shown that when only one observation near noontime is used to estimate UV dose, errors in the range of -61% to 48% can result, depending on cloud conditions. The RMS difference is 9% and it increases to 13% when off-noon hour (±2 hrs) observations are used to estimate the UV flux over Queenstown, MD.

  10. Bias adjustment of satellite-based precipitation estimation using gauge observations: A case study in Chile

    NASA Astrophysics Data System (ADS)

    Yang, Zhongwen; Hsu, Kuolin; Sorooshian, Soroosh; Xu, Xinyi; Braithwaite, Dan; Verbist, Koen M. J.

    2016-04-01

    Satellite-based precipitation estimates (SPEs) are promising alternative precipitation data for climatic and hydrological applications, especially for regions where ground-based observations are limited. However, existing satellite-based rainfall estimations are subject to systematic biases. This study aims to adjust the biases in the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Cloud Classification System (PERSIANN-CCS) rainfall data over Chile, using gauge observations as reference. A novel bias adjustment framework, termed QM-GW, is proposed based on the nonparametric quantile mapping approach and a Gaussian weighting interpolation scheme. The PERSIANN-CCS precipitation estimates (daily, 0.04°×0.04°) over Chile are adjusted for the period of 2009-2014. The historical data (satellite and gauge) for 2009-2013 are used to calibrate the methodology; nonparametric cumulative distribution functions of satellite and gauge observations are estimated at every 1°×1° box region. One year (2014) of gauge data was used for validation. The results show that the biases of the PERSIANN-CCS precipitation data are effectively reduced. The spatial patterns of adjusted satellite rainfall show high consistency to the gauge observations, with reduced root-mean-square errors and mean biases. The systematic biases of the PERSIANN-CCS precipitation time series, at both monthly and daily scales, are removed. The extended validation also verifies that the proposed approach can be applied to adjust SPEs into the future, without further need for ground-based measurements. This study serves as a valuable reference for the bias adjustment of existing SPEs using gauge observations worldwide.

  11. Satellite-borne study of seismic phenomena by low frequency magnetic field observations

    NASA Astrophysics Data System (ADS)

    Schwingenschuh, Konrad; Magnes, Werner; Xuhui, Shen; Wang, Jindong; Pollinger, Andreas; Hagen, Christian; Prattes, Gustav; Eichelberger, Hans-Ulrich; Wolbang, Daniel; Boudjada, Mohammed Y.; Besser, Bruno P.; Rozhnoi, Alexander A.; Zhang, Tielong

    2015-04-01

    A combined scalar-vector magnetic field experiment will be flown on the upcoming CSES mission (China Seismo-Electromagnetic Satellite). Magnetic field data from DC to 30 Hz will be measured with an accuracy of about 10 pT. A fluxgate instrument will provide the 3 magnetic field components and a new type of an optically pumped magnetometer [see Pollinger, 2010] will measure the magnitude of the ambient magnetic field. The satellite will operate in a Sun synchronous polar orbit at an altitude of about 500 km and with an inclination of 97°. We present a model of magnetic field fluctuations in the upper ionosphere based on previous satellite observations and on a model of the lithospheric-atmospheric-ionospheric coupling. Pollinger et al., CDSM-a new scalar magnetometer, EGU General Assembly 2010

  12. Use of dust storm observations on satellite images to identify areas vulnerable to severe wind erosion

    USGS Publications Warehouse

    Breed, C.S.; McCauley, J.F.

    1986-01-01

    Blowing dust is symptomatic of severe wind erosion and deterioration of soils in areas undergoing dessication and/or devegetation. Dust plumes on satellite images can commonly be traced to sources in marginally arable semiarid areas where protective lag gravels or vegetation have been removed and soils are dry, as demonstrated for the Portales Valley, New Mexico. Images from Landsat and manned orbiters such as Skylab and the Space Shuttle are useful for illustrating the regional relations of airborne dust plumes to source areas. Geostationary satellites such as GOES are useful in tracking the time-histories of episodic dust storms. These events sometimes go unrecognized by weather observers and are the precursors of long-term land degradation trends. In areas where soil maps and meteorological data are inadequate, satellite images provide a means for identifying problem areas where measures are needed to control or mitigate wind erosion. ?? 1986 D. Reidel Publishing Company.

  13. A collection of Galilean satellite eclipse observations, 1652-1983. I

    NASA Technical Reports Server (NTRS)

    Lieske, J. H.

    1986-01-01

    The most complete collection of extant Galilean satellite eclipse observations since 1652 has been assembled. Since many of the old data exist only in manuscript form or in archaic forms (e.g., apparent time, local time, sidereal time, Julian calendar, etc.), they have been reduced to a modern proleptic Universal Time (UT) system (where the day begins at midnight) on the Gregorian calendar. Many of the data had been presumed to be lost for more than a century and since they are very valuable for discussion of long-term effects on the satellites, they are presented here for present as well as future generations of astronomers. The data are invaluable for long-term studies of Galilean satellite motion and for the determination of physical parameters.

  14. Seismic, satellite, and site observations of internal solitary waves in the NE South China Sea.

    PubMed

    Tang, Qunshu; Wang, Caixia; Wang, Dongxiao; Pawlowicz, Rich

    2014-01-01

    Internal solitary waves (ISWs) in the NE South China Sea (SCS) are tidally generated at the Luzon Strait. Their propagation, evolution, and dissipation processes involve numerous issues still poorly understood. Here, a novel method of seismic oceanography capable of capturing oceanic finescale structures is used to study ISWs in the slope region of the NE SCS. Near-simultaneous observations of two ISWs were acquired using seismic and satellite imaging, and water column measurements. The vertical and horizontal length scales of the seismic observed ISWs are around 50 m and 1-2 km, respectively. Wave phase speeds calculated from seismic observations, satellite images, and water column data are consistent with each other. Observed waveforms and vertical velocities also correspond well with those estimated using KdV theory. These results suggest that the seismic method, a new option to oceanographers, can be further applied to resolve other important issues related to ISWs. PMID:24948180

  15. Seismic, satellite, and site observations of internal solitary waves in the NE South China Sea.

    PubMed

    Tang, Qunshu; Wang, Caixia; Wang, Dongxiao; Pawlowicz, Rich

    2014-06-20

    Internal solitary waves (ISWs) in the NE South China Sea (SCS) are tidally generated at the Luzon Strait. Their propagation, evolution, and dissipation processes involve numerous issues still poorly understood. Here, a novel method of seismic oceanography capable of capturing oceanic finescale structures is used to study ISWs in the slope region of the NE SCS. Near-simultaneous observations of two ISWs were acquired using seismic and satellite imaging, and water column measurements. The vertical and horizontal length scales of the seismic observed ISWs are around 50 m and 1-2 km, respectively. Wave phase speeds calculated from seismic observations, satellite images, and water column data are consistent with each other. Observed waveforms and vertical velocities also correspond well with those estimated using KdV theory. These results suggest that the seismic method, a new option to oceanographers, can be further applied to resolve other important issues related to ISWs.

  16. Seismic, satellite, and site observations of internal solitary waves in the NE South China Sea

    PubMed Central

    Tang, Qunshu; Wang, Caixia; Wang, Dongxiao; Pawlowicz, Rich

    2014-01-01

    Internal solitary waves (ISWs) in the NE South China Sea (SCS) are tidally generated at the Luzon Strait. Their propagation, evolution, and dissipation processes involve numerous issues still poorly understood. Here, a novel method of seismic oceanography capable of capturing oceanic finescale structures is used to study ISWs in the slope region of the NE SCS. Near-simultaneous observations of two ISWs were acquired using seismic and satellite imaging, and water column measurements. The vertical and horizontal length scales of the seismic observed ISWs are around 50 m and 1–2 km, respectively. Wave phase speeds calculated from seismic observations, satellite images, and water column data are consistent with each other. Observed waveforms and vertical velocities also correspond well with those estimated using KdV theory. These results suggest that the seismic method, a new option to oceanographers, can be further applied to resolve other important issues related to ISWs. PMID:24948180

  17. Astrometric observations of satellites of Uranus using a 26-inch refractor in 2007-2011

    NASA Astrophysics Data System (ADS)

    Roshchina, E. A.; Izmailov, I. S.; Kiseleva, T. P.

    2015-05-01

    This paper reports CCD observations of Uranus and its main satellites using a 26-inch refractor at the Pulkovo Observatory in 2007-2011. These are 2450 CCD frames with images of Uranus and its four main satellites, i.e., Ariel, Umbriel, Titania, and Oberon. The field of view of the FLI Proline 9000 CCD camera is 12' × 12', which allows us to obtain stars and perform astrometric reduction by Turner's method to determine the satellites' equatorial coordinates. UCAC2 is used as a reference catalogue. The equatorial coordinates are compared with the GUST 06 theory. The average accuracy of normal places is 0.030″-0.040″ in right ascension and declination. The positions of the satellites and their theoretical uranocentric coordinates by GUST 06 are used to calculate the equatorial coordinates of Uranus. The positions of Uranus are compared with the INPOP10 planetary theory. The paper also presents the satellites' differential coordinates relative to one another.

  18. Ice surface temperatures: seasonal cycle and daily variability from in-situ and satellite observations

    NASA Astrophysics Data System (ADS)

    Madsen, Kristine S.; Dybkjær, Gorm; Høyer, Jacob L.; Nielsen-Englyst, Pia; Rasmussen, Till A. S.; Tonboe, Rasmus T.

    2016-04-01

    Surface temperature is an important parameter for understanding the climate system, including the Polar Regions. Yet, in-situ temperature measurements over ice- and snow covered regions are sparse and unevenly distributed, and atmospheric circulation models estimating surface temperature may have large biases. To change this picture, we will analyse the seasonal cycle and daily variability of in-situ and satellite observations, and give an example of how to utilize the data in a sea ice model. We have compiled a data set of in-situ surface and 2 m air temperature observations over land ice, snow, sea ice, and from the marginal ice zone. 2523 time series of varying length from 14 data providers, with a total of more than 13 million observations, have been quality controlled and gathered in a uniform format. An overview of this data set will be presented. In addition, IST satellite observations have been processed from the Metop/AVHRR sensor and a merged analysis product has been constructed based upon the Metop/AVHRR, IASI and Modis IST observations. The satellite and in-situ observations of IST are analysed in parallel, to characterize the IST variability on diurnal and seasonal scales and its spatial patterns. The in-situ data are used to estimate sampling effects within the satellite observations and the good coverage of the satellite observations are used to complete the geographical variability. As an example of the application of satellite IST data, results will be shown from a coupled HYCOM-CICE ocean and sea ice model run, where the IST products have been ingested. The impact of using IST in models will be assessed. This work is a part of the EUSTACE project under Horizon 2020, where the ice surface temperatures form an important piece of the puzzle of creating an observationally based record of surface temperatures for all corners of the Earth, and of the ESA GlobTemperature project which aims at applying surface temperatures in models in order to

  19. A Geostationary Satellite Constellation for Observing Global Air Quality: Status of the CEOS Activity

    NASA Astrophysics Data System (ADS)

    Al-Saadi, J. A.; Zehner, C.

    2011-12-01

    Several countries and space agencies are currently planning to launch geostationary satellites in the 2017-2022 time frame to obtain atmospheric composition measurements for characterizing anthropogenic and natural distributions of tropospheric ozone, aerosols, and their precursors, which are important factors in understanding air quality and climate change. While a single geostationary satellite can view only a portion of the globe, it is possible for a minimum of three geostationary satellites, positioned to view Europe/Middle East/Africa, Asia/Australasia, and the Americas, to collectively provide near-global coverage. Harmonizing the planned geostationary missions to be contemporaneous and have common observing capabilities and data distribution protocols would synergistically enable critically needed understanding of the interactions between regional and global atmospheric composition and of the implications for air quality and climate. Such activities would directly address societal benefit areas of the Global Earth Observation System of Systems (GEOSS), including Health, Energy, Climate, Disasters, and Ecosystems, and are responsive to the requirements of each mission to provide advanced user services and societal benefits. Over the past 2 years, the Atmospheric Composition Constellation (ACC) of the Committee on Earth Observation Satellites (CEOS) has developed a white paper describing such collaboration and the benefits to be derived from it. The resulting ACC recommendations were endorsed by CEOS in May 2011. Here we will present an update on collaborative activities and next steps. This presentation is envisioned to serve as an introduction to the oral sessions associated with Session A.25.

  20. The Role of Satellite Earth Observation Data in Monitoring and Verifying International Environmental Treaties

    NASA Technical Reports Server (NTRS)

    Johnston, Shaida

    2004-01-01

    The term verification implies compliance verification in the language of treaty negotiation and implementation, particularly in the fields of disarmament and arms control. The term monitoring on the other hand, in both environmental and arms control treaties, has a much broader interpretation which allows for use of supporting data sources that are not necessarily acceptable or adequate for direct verification. There are many ways that satellite Earth observation (EO) data can support international environmental agreements, from national forest inventories to use in geographic information system (GIs) tools. Though only a few references to satellite EO data and their use exist in the treaties themselves, an expanding list of applications can be considered in support of multilateral environmental agreements (MEAs). This paper explores the current uses of satellite Earth observation data which support monitoring activities of major environmental treaties and draws conclusions about future missions and their data use. The scope of the study includes all phases of environmental treaty fulfillment - development, monitoring, and enforcement - and includes a multinational perspective on the use of satellite Earth observation data for treaty support.

  1. Heavy precipitation retrieval from combined satellite observations and ground-based lightning measurements

    NASA Astrophysics Data System (ADS)

    Mugnai, A.; Dietrich, S.; Casella, D.; di Paola, F.; Formenton, M.; Sanò, P.

    2010-09-01

    We have developed a series of algorithms for the retrieval of precipitation (especially, heavy precipitation) over the Mediterranean area using satellite observations from the available microwave (MW) radiometers onboard low Earth orbit (LEO) satellites and from the visible-infrared (VIS-IR) SEVIRI radiometer onboard the European geosynchronous (GEO) satellite Meteosat Second Generation (MSG), in conjunction with lightning data from ground-based networks - such as ZEUS and LINET. These are: • A new approach for precipitation retrieval from space (which we call the Cloud Dynamics and Radiation Database approach, CDRD) that incorporates lightning and environmental/dynamical information in addition to the upwelling microwave brightness temperatures (TB’s) so as to reduce the retrieval uncertainty and improve the retrieval performance; • A new combined MW-IR technique for producing frequent precipitation retrievals from space (which we call PM-GCD technique), that uses passive-microwave (PM) retrievals in conjunction with lightning information and the Global Convection Detection (GCD) technique to discriminate deep convective clouds within the GEO observations; • A new morphing approach (which we call the Lightning-based Precipitation Evolving Technique, L-PET) that uses the available lightning measurements for propagating the rainfall estimates from satellite-borne MW radiometers to a much higher time resolution than the MW observations. We will present and discuss our combined MW/IR/lightning precipitation algorithms and analyses with special reference to some case studies over the western Mediterranean.

  2. Establishing the Antarctic Dome C community reference standard site towards consistent measurements from Earth observation satellites

    USGS Publications Warehouse

    Cao, C.; Uprety, S.; Xiong, J.; Wu, A.; Jing, P.; Smith, D.; Chander, G.; Fox, N.; Ungar, S.

    2010-01-01

    Establishing satellite measurement consistency by using common desert sites has become increasingly more important not only for climate change detection but also for quantitative retrievals of geophysical variables in satellite applications. Using the Antarctic Dome C site (75°06′S, 123°21′E, elevation 3.2 km) for satellite radiometric calibration and validation (Cal/Val) is of great interest owing to its unique location and characteristics. The site surface is covered with uniformly distributed permanent snow, and the atmospheric effect is small and relatively constant. In this study, the long-term stability and spectral characteristics of this site are evaluated using well-calibrated satellite instruments such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Preliminary results show that despite a few limitations, the site in general is stable in the long term, the bidirectional reflectance distribution function (BRDF) model works well, and the site is most suitable for the Cal/Val of reflective solar bands in the 0.4–1.0 µm range. It was found that for the past decade, the reflectivity change of the site is within 1.35% at 0.64 µm, and interannual variability is within 2%. The site is able to resolve calibration biases between instruments at a level of ~1%. The usefulness of the site is demonstrated by comparing observations from seven satellite instruments involving four space agencies, including OrbView-2–SeaWiFS, Terra–Aqua MODIS, Earth Observing 1 (EO-1) – Hyperion, Meteorological Operational satellite programme (MetOp) – Advanced Very High Resolution Radiometer (AVHRR), Envisat Medium Resolution Imaging Spectrometer (MERIS) – dvanced Along-Track Scanning Radiometer (AATSR), and Landsat 7 Enhanced Thematic Mapper Plus (ETM+). Dome C is a promising candidate site for climate quality calibration of satellite radiometers towards more consistent satellite measurements, as part

  3. Astrometric positions for 18 irregular satellites of giant planets from 23 years of observations

    NASA Astrophysics Data System (ADS)

    Gomes-Júnior, A. R.; Assafin, M.; Vieira-Martins, R.; Arlot, J.-E.; Camargo, J. I. B.; Braga-Ribas, F.; da Silva Neto, D. N.; Andrei, A. H.; Dias-Oliveira, A.; Morgado, B. E.; Benedetti-Rossi, G.; Duchemin, Y.; Desmars, J.; Lainey, V.; Thuillot, W.

    2015-08-01

    Context. The irregular satellites of the giant planets are believed to have been captured during the evolution of the solar system. Knowing their physical parameters, such as size, density, and albedo is important for constraining where they came from and how they were captured. The best way to obtain these parameters are observations in situ by spacecrafts or from stellar occultations by the objects. Both techniques demand that the orbits are well known. Aims: We aimed to obtain good astrometric positions of irregular satellites to improve their orbits and ephemeris. Methods: We identified and reduced observations of several irregular satellites from three databases containing more than 8000 images obtained between 1992 and 2014 at three sites (Observatório do Pico dos Dias, Observatoire de Haute-Provence, and European Southern Observatory - La Silla). We used the software Platform for Reduction of Astronomical Images Automatically (PRAIA) to make the astrometric reduction of the CCD frames. The UCAC4 catalog represented the International Celestial Reference System in the reductions. Identification of the satellites in the frames was done through their ephemerides as determined from the SPICE/NAIF kernels. Some procedures were followed to overcome missing or incomplete information (coordinates, date), mostly for the older images. Results: We managed to obtain more than 6000 positions for 18 irregular satellites: 12 of Jupiter, 4 of Saturn, 1 of Uranus (Sycorax), and 1 of Neptune (Nereid). For some satellites the number of obtained positions is more than 50% of what was used in earlier orbital numerical integrations. Conclusions: Comparison of our positions with recent JPL ephemeris suggests there are systematic errors in the orbits for some of the irregular satellites. The most evident case was an error in the inclination of Carme. Position tables are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http

  4. A Bayesian kriging approach for blending satellite and ground precipitation observations

    USGS Publications Warehouse

    Verdin, Andrew P.; Rajagopalan, Balaji; Kleiber, William; Funk, Christopher C.

    2015-01-01

    Drought and flood management practices require accurate estimates of precipitation. Gauge observations, however, are often sparse in regions with complicated terrain, clustered in valleys, and of poor quality. Consequently, the spatial extent of wet events is poorly represented. Satellite-derived precipitation data are an attractive alternative, though they tend to underestimate the magnitude of wet events due to their dependency on retrieval algorithms and the indirect relationship between satellite infrared observations and precipitation intensities. Here we offer a Bayesian kriging approach for blending precipitation gauge data and the Climate Hazards Group Infrared Precipitation satellite-derived precipitation estimates for Central America, Colombia, and Venezuela. First, the gauge observations are modeled as a linear function of satellite-derived estimates and any number of other variables—for this research we include elevation. Prior distributions are defined for all model parameters and the posterior distributions are obtained simultaneously via Markov chain Monte Carlo sampling. The posterior distributions of these parameters are required for spatial estimation, and thus are obtained prior to implementing the spatial kriging model. This functional framework is applied to model parameters obtained by sampling from the posterior distributions, and the residuals of the linear model are subject to a spatial kriging model. Consequently, the posterior distributions and uncertainties of the blended precipitation estimates are obtained. We demonstrate this method by applying it to pentadal and monthly total precipitation fields during 2009. The model's performance and its inherent ability to capture wet events are investigated. We show that this blending method significantly improves upon the satellite-derived estimates and is also competitive in its ability to represent wet events. This procedure also provides a means to estimate a full conditional distribution

  5. A Bayesian kriging approach for blending satellite and ground precipitation observations

    NASA Astrophysics Data System (ADS)

    Verdin, Andrew; Rajagopalan, Balaji; Kleiber, William; Funk, Chris

    2015-02-01

    Drought and flood management practices require accurate estimates of precipitation. Gauge observations, however, are often sparse in regions with complicated terrain, clustered in valleys, and of poor quality. Consequently, the spatial extent of wet events is poorly represented. Satellite-derived precipitation data are an attractive alternative, though they tend to underestimate the magnitude of wet events due to their dependency on retrieval algorithms and the indirect relationship between satellite infrared observations and precipitation intensities. Here we offer a Bayesian kriging approach for blending precipitation gauge data and the Climate Hazards Group Infrared Precipitation satellite-derived precipitation estimates for Central America, Colombia, and Venezuela. First, the gauge observations are modeled as a linear function of satellite-derived estimates and any number of other variables—for this research we include elevation. Prior distributions are defined for all model parameters and the posterior distributions are obtained simultaneously via Markov chain Monte Carlo sampling. The posterior distributions of these parameters are required for spatial estimation, and thus are obtained prior to implementing the spatial kriging model. This functional framework is applied to model parameters obtained by sampling from the posterior distributions, and the residuals of the linear model are subject to a spatial kriging model. Consequently, the posterior distributions and uncertainties of the blended precipitation estimates are obtained. We demonstrate this method by applying it to pentadal and monthly total precipitation fields during 2009. The model's performance and its inherent ability to capture wet events are investigated. We show that this blending method significantly improves upon the satellite-derived estimates and is also competitive in its ability to represent wet events. This procedure also provides a means to estimate a full conditional distribution

  6. An analysis of the upper atmospheric wind observed by LOGACS. [satellite Low-G Accelerometer Calibration System

    NASA Technical Reports Server (NTRS)

    Wu, S. T.; Matsushita, S.; Devries, L. L.

    1974-01-01

    Wind velocities at 140 to 200 km altitude were observed by a low-g accelerometer calibration system (LOGACS) flown on an Agena satellite during a geomagnetic storm. An interesting wind reversal observed by the satellite at auroral latitudes is satisfactorily explained by the neutral air motion caused by the E x B drift deduced from the ground-based geomagnetic data recorded at stations near the meridian of the satellite orbit.

  7. Current Sounding Capability From Satellite Meteorological Observation With Ultraspectral Infrared Instruments

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Liu, Xu; Larar, Allen M.

    2008-01-01

    Ultraspectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. The intent of the measurement of tropospheric thermodynamic state and trace abundances is the initialization of climate models and the monitoring of air quality. The NPOESS Airborne Sounder Testbed-Interferometer (NAST-I), designed to support the development of future satellite temperature and moisture sounders, aboard high altitude aircraft has been collecting data throughout many field campaigns. An advanced retrieval algorithm developed with NAST-I is now applied to satellite data collected with the Atmospheric InfraRed Sounder (AIRS) on the Aqua satellite launched on 4 May 2002 and the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite launched on October 19, 2006. These instruments possess an ultra-spectral resolution, for example, both IASI and NAST-I have 0.25 cm-1 and a spectral coverage from 645 to 2760 cm-1. The retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. The physical inversion scheme has been developed, dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders, to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A fast radiative transfer model, which applies to the clouded atmosphere, is used for atmospheric profile and cloud parameter retrieval. A one-dimensional (1-d) variational multi-variable inversion solution is used to improve an iterative background state defined by an eigenvector-regression-retrieval. The solution is iterated in order to account for non-linearity in the 1-d variational solution. It is shown that relatively accurate temperature and moisture retrievals can be achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to

  8. Detailed Analysis of Indian Summer Monsoon Rainfall Processes with Modern/High-Quality Satellite Observations

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Kuo, Kwo-Sen; Mehta, Amita V.; Yang, Song

    2007-01-01

    We examine, in detail, Indian Summer Monsoon rainfall processes using modernhigh quality satellite precipitation measurements. The focus here is on measurements derived from three NASA cloud and precipitation satellite missionslinstruments (TRMM/PR&TMI, AQUNAMSRE, and CLOUDSATICPR), and a fourth TRMM Project-generated multi-satellite precipitation measurement dataset (viz., TRMM standard algorithm 3b42) -- all from a period beginning in 1998 up to the present. It is emphasized that the 3b42 algorithm blends passive microwave (PMW) radiometer-based precipitation estimates from LEO satellites with infi-ared (IR) precipitation estimates from a world network of CEO satellites (representing -15% of the complete space-time coverage) All of these observations are first cross-calibrated to precipitation estimates taken from standard TRMM combined PR-TMI algorithm 2b31, and second adjusted at the large scale based on monthly-averaged rain-gage measurements. The blended approach takes advantage of direct estimates of precipitation from the PMW radiometerequipped LEO satellites -- but which suffer fi-om sampling limitations -- in combination with less accurate IR estimates from the optical-infrared imaging cameras on GEO satellites -- but which provide continuous diurnal sampling. The advantages of the current technologies are evident in the continuity and coverage properties inherent to the resultant precipitation datasets that have been an outgrowth of these stable measuring and retrieval technologies. There is a wealth of information contained in the current satellite measurements of precipitation regarding the salient precipitation properties of the Indian Summer Monsoon. Using different datasets obtained from the measuring systems noted above, we have analyzed the observations cast in the form of: (1) spatially distributed means and variances over the hierarchy of relevant time scales (hourly I diurnally, daily, monthly, seasonally I intra-seasonally, and inter

  9. Integrating Satellite, Radar and Surface Observation with Time and Space Matching

    NASA Astrophysics Data System (ADS)

    Ho, Y.; Weber, J.

    2015-12-01

    The Integrated Data Viewer (IDV) from Unidata is a Java™-based software framework for analyzing and visualizing geoscience data. It brings together the ability to display and work with satellite imagery, gridded data, surface observations, balloon soundings, NWS WSR-88D Level II and Level III RADAR data, and NOAA National Profiler Network data, all within a unified interface. Applying time and space matching on the satellite, radar and surface observation datasets will automatically synchronize the display from different data sources and spatially subset to match the display area in the view window. These features allow the IDV users to effectively integrate these observations and provide 3 dimensional views of the weather system to better understand the underlying dynamics and physics of weather phenomena.

  10. A Model Assessment of Satellite Observed Trends in Polar Sea Ice Extents

    NASA Technical Reports Server (NTRS)

    Vinnikov, Konstantin Y.; Cavalieri, Donald J.; Parkinson, Claire L.

    2005-01-01

    For more than three decades now, satellite passive microwave observations have been used to monitor polar sea ice. Here we utilize sea ice extent trends determined from primarily satellite data for both the Northern and Southern Hemispheres for the period 1972(73)-2004 and compare them with results from simulations by eleven climate models. In the Northern Hemisphere, observations show a statistically significant decrease of sea ice extent and an acceleration of sea ice retreat during the past three decades. However, from the modeled natural variability of sea ice extents in control simulations, we conclude that the acceleration is not statistically significant and should not be extrapolated into the future. Observations and model simulations show that the time scale of climate variability in sea ice extent in the Southern Hemisphere is much larger than in the Northern Hemisphere and that the Southern Hemisphere sea ice extent trends are not statistically significant.

  11. Investigation of Interpolation for Solar Irradiation in Non-Observed Point Based on Satellite Images

    NASA Astrophysics Data System (ADS)

    Shinoda, Yukio; Fujisawa, Sei; Seki, Tomomichi

    Penetrating the Photovoltaic Power Generation System (PV) on an enormous scale over a next decade has some crucial problems which affect on, for example, power grid stabilization and operation including existing power stations for electric power utilities. It would be therefore important for future operation to estimate power output generated by PV in advance. We focus on interpolation using observed solar irradiation (SI) and brightness of pixel on a satellite visible image for estimating SI even in non-observed point. Our results by single regression analysis between observed SI and brightness on a satellite image as cloudiness show that a shift of highest determination coefficient on each hour would represent solar movement and this higher determination coefficient would indicate a position which SI and cloud would cross. Finally assessment of error in this interpolation shows enough accuracy at least in daytime period, which is important for electricity utilities.

  12. The study of the effect of solar eclipses on the ionosphere based on satellite beacon observations

    NASA Astrophysics Data System (ADS)

    Cohen, E. A.

    1984-06-01

    The ionospheric effect of a solar eclipse was first noticed in 1927 during an English eclipse. In studies of the effects of solar eclipses on the ionosphere by ionosondes during the next 30 years, the obtained results were difficult to interpret. Results obtained after the introduction of additional techniques indicate that the redistribution of ionization due to temperature changes is important, as is recombination. More recently, a more detailed study of the eclipse effects throughout the ionosphere was made possible as a result of the addition of the satellite beacon observations. The present investigation provides a review of the study of eclipse effects on the ionosphere based on satellite beacon observations. Attention is given to early observations, and total and partial solar eclipses over North America, Africa, Australia, and India.

  13. Analytic Perturbation Method for Estimating Ground Flash Fraction from Satellite Lightning Observations

    NASA Technical Reports Server (NTRS)

    Koshak, William; Solakiewicz, Richard

    2013-01-01

    An analytic perturbation method is introduced for estimating the lightning ground flash fraction in a set of N lightning flashes observed by a satellite lightning mapper. The value of N is large, typically in the thousands, and the observations consist of the maximum optical group area produced by each flash. The method is tested using simulated observations that are based on Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) data. National Lightning Detection NetworkTM (NLDN) data is used to determine the flash-type (ground or cloud) of the satellite-observed flashes, and provides the ground flash fraction truth for the simulation runs. It is found that the mean ground flash fraction retrieval errors are below 0.04 across the full range 0-1 under certain simulation conditions. In general, it is demonstrated that the retrieval errors depend on many factors (i.e., the number, N, of satellite observations, the magnitude of random and systematic measurement errors, and the number of samples used to form certain climate distributions employed in the model).

  14. Fast emission estimates in China and South Africa constrained by satellite observations

    NASA Astrophysics Data System (ADS)

    Mijling, Bas; van der A, Ronald

    2013-04-01

    Emission inventories of air pollutants are crucial information for policy makers and form important input data for air quality models. Unfortunately, bottom-up emission inventories, compiled from large quantities of statistical data, are easily outdated for emerging economies such as China and South Africa, where rapid economic growth change emissions accordingly. Alternatively, top-down emission estimates from satellite observations of air constituents have important advantages of being spatial consistent, having high temporal resolution, and enabling emission updates shortly after the satellite data become available. However, constraining emissions from observations of concentrations is computationally challenging. Within the GlobEmission project (part of the Data User Element programme of ESA) a new algorithm has been developed, specifically designed for fast daily emission estimates of short-lived atmospheric species on a mesoscopic scale (0.25 × 0.25 degree) from satellite observations of column concentrations. The algorithm needs only one forward model run from a chemical transport model to calculate the sensitivity of concentration to emission, using trajectory analysis to account for transport away from the source. By using a Kalman filter in the inverse step, optimal use of the a priori knowledge and the newly observed data is made. We apply the algorithm for NOx emission estimates in East China and South Africa, using the CHIMERE chemical transport model together with tropospheric NO2 column retrievals of the OMI and GOME-2 satellite instruments. The observations are used to construct a monthly emission time series, which reveal important emission trends such as the emission reduction measures during the Beijing Olympic Games, and the impact and recovery from the global economic crisis. The algorithm is also able to detect emerging sources (e.g. new power plants) and improve emission information for areas where proxy data are not or badly known (e

  15. Comparing regional modeling (CHIMERE) and satellite observations of aerosols (PARASOL): Methodology and case study over Mexico

    NASA Astrophysics Data System (ADS)

    Stromatas, Stavros

    2010-05-01

    S. Stromatas (1), S. Turquety (1), H. Chepfer (1), L. Menut (1), B. Bessagnet (2), JC Pere (2), D. Tanré (3) . (1) Laboratoire de Météorologie Dynamique, CNRS/IPSL, École Polytechnique, 91128 Palaiseau Cedex, France, (2) INERIS, Institut National de l'Environnement Industriel et des Risques, Parc technologique ALATA, 60550 Verneuil en Halatte, FRANCE, (3) Laboratoire d'Optique Atmosphérique/CNRS Univ. des Sciences et Tech. de Lille, 59650 - Villeneuve d'Ascq, France. Atmospheric suspended particles (aerosols) have significant radiative and environmental impacts, affecting human health, visibility and climate. Therefore, they are regulated by air quality standards worldwide, and monitored by regional observation networks. Satellite observations vastly improve the horizontal and temporal coverage, providing daily distributions. Aerosols are currently estimated using aerosol optical depth (AOD) retrievals, a quantitative measure of the extinction of solar radiation by aerosol scattering and absorption between the point of observation and the top of the atmosphere. Even though remarkable progresses in aerosol modeling by chemistry-transport models (CTM) and measurement experiments have been made in recent years, there is still a significant divergence between the modeled and observed results. However, AOD retrievals from satellites remains a highly challenging task mostly because it depends on a variety of different parameters such as cloud contamination, surface reflectance contributions and a priori assumptions on aerosol types, each one of them incorporating its own difficulties. Therefore, comparisons between CTM and observations are often difficult to interpret. In this presentation, we will discuss comparisons between regional modeling (CHIMERE CTM) over Mexico and satellite observations obtained by the POLDER instrument embarked on PARASOL micro-satellite. After a comparison of the model AOD with the retrieved L2 AOD, we will present an alternative

  16. Satellite Phenology Observations Inform Peak Season of Allergenic Grass Pollen Aerobiology across Two Continents

    NASA Astrophysics Data System (ADS)

    Huete, A. R.; Devadas, R.; Davies, J.

    2015-12-01

    Pollen exposure and prevalence of allergenic diseases have increased in many parts of the world during the last 30 years, with exposure to aeroallergen grass pollen expected to intensify with climate change, raising increased concerns for allergic diseases. The primary contributing factors to higher allergenic plant species presence are thought to be climate change, land conversion, and biotic mixing of species. Conventional methods for monitoring airborne pollen are hampered by a lack of sampling sites and heavily rely on meteorology with less attention to land cover updates and monitoring of key allergenic species phenology stages. Satellite remote sensing offers an alternative method to overcome the restrictive coverage afforded by in situ pollen networks by virtue of its synoptic coverage and repeatability of measurements that enable timely updates of land cover and land use information and monitoring landscape dynamics and interactions with human activity and climate. In this study, we assessed the potential of satellite observations of urban/peri-urban environments to directly inform landscape conditions conducive to pollen emissions. We found satellite measurements of grass cover phenological evolution to be highly correlated with in situ aerobiological grass pollen concentrations in five urban centres located across two hemispheres (Australia and France). Satellite greenness data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were found to be strongly synchronous with grass pollen aerobiology in both temperate grass dominated sites (France and Melbourne), as well as in Sydney, where multiple pollen peaks coincided with the presence of subtropical grasses. Employing general additive models (GAM), the satellite phenology data provided strong predictive capabilities to inform airborne pollen levels and forecast periods of grass pollen emissions at all five sites. Satellite phenology offer promising opportunities of improving public health risk

  17. Stereographic Observations from Geosynchronous Satellites: An Important New Tool for the Atmospheric Sciences.

    NASA Astrophysics Data System (ADS)

    Hasler, A. F.

    1981-02-01

    The capability of making stereographic observations of clouds and their temporal changes from two simultaneously scanning geosynchronous satellites is a new basic meteorological analysis tool with a broad spectrum of applications. Stereo height measurements, because of their higher horizontal resolution and dependence on only straightforward geometric relationships, represent a big improvement over previously used infrared-based techniques. Verification using high altitude mountain lakes indicates that stereo cloud height accuracies of ±0.1-0.2 km are possible near reference points of known elevation. The smallest cloud features observed by the present operational geosynchronous satellites (GOES), which have spatial and temporal resolution of 1.0 km and 3 min, can be measured with height accuracies of ±0.5 km. Absolute stereo height accuracy, far from landmarks, is also about ±0.5 km if accurate navigation solutions are available for both satellites. Computer remapping of digital image pairs allows the display and height measurement on time sequences of stereo images using an interactive information processing system. Rapid time sequencing of the series of stereo image pairs gives an effective 4-dimensional representation of cloud dynamics. Several interactive techniques have been developed for point measurements of cloud height and cloud height contouring. The stereo observations have been applied to meteorological problems, including: cloud top height contours of intense convective clouds in hurricanes and severe thunderstorms; cloud top and cloud base height estimates for satellite cloud-wind altitude assignment; atmospheric temperature profiles from the combination of stereo heights and infrared cloud top temperatures; determination of cloud emissivity: and finally, comparisons are made between stereo-observed, tropopause-penetrating thunderstorm tops with altitudes up to 17 km and severe weather observations from radar and surface reports. Present stereo

  18. NASA Satellite Observations: A Unique Asset for the Study of the Environment and Implications for Public Health

    NASA Technical Reports Server (NTRS)

    Estes Sue M.

    2010-01-01

    This slide presentation highlights how satellite observation systems are assets for studying the environment in relation to public health. It includes information on current and future satellite observation systems, NASA's public health and safety research, surveillance projects, and NASA's public health partners.

  19. Sentinel-2: next generation satellites for optical land observation from space

    NASA Astrophysics Data System (ADS)

    Lautenschläger, G.; Gessner, R.; Gockel, W.; Haas, C.; Schweickert, G.; Bursch, S.; Welsch, M.; Sontag, H.

    2013-10-01

    The first Sentinel-2 satellites, which constitute the next generation of operational Earth observation satellites for optical land monitoring from space, are undergoing completion in the facilities at Astrium ready for launch end 2014. Sentinel-2 will feature a major breakthrough in the area of optical land observation since it will for the first time enable continuous and systematic acquisition of all land surfaces world-wide with the Multi-Spectral Instrument (MSI), thus providing the basis for a truly operational service. Flying in the same orbital plane and spaced at 180°, the constellation of two satellites, designed for an in-orbit nominal operational lifetime of 7 years each, will acquire all land surfaces in only 5 days at the equator. In order to support emergency operations, the satellites can further be operated in an extended observation mode allowing to image any point on Earth even on a daily basis. MSI acquires images in 13 spectral channels from Visible-to-Near Infrared (VNIR) to Short Wave Infrared (SWIR) with a swath of almost 300 km on ground and a spatial resolution up to 10 m. The data ensure continuity to the existing data sets produced by the series of Landsat and SPOT satellites, and will further provide detailed spectral information to enable derivation of biophysical or geophysical products. Excellent geometric image quality performances are achieved with geolocation better than 16 m, thanks to an innovative instrument design in conjunction with a high-performance satellite AOCS subsystem centered around a 2-band GPS receiver, high-performance star trackers and a fiberoptic gyro. To cope with the high data volume on-board, data are compressed using a state-of-the-art wavelet compression scheme. Thanks to a powerful mission data handling system built around a newly developed very large solid-state mass memory based on flash technology, on-board compression losses will be kept to a minimum. The Sentinel-2 satellite design features a highly

  20. Observations on the Reliability of Rubidium Frequency Standards on Block 2/2A GPS Satellites

    NASA Technical Reports Server (NTRS)

    Dieter, Gary L.

    1996-01-01

    Currently, the block 2/2A Global Positioning System (GPS) satellites are equipped with two rubidium frequency standards. These frequency standards were originally intended to serve as the back-ups to two cesium frequency standards. As the constellation ages, the master Control Station is forced to initialize and increasing number or rubidium frequency standards. Unfortunately the operational use of these frequency standards has not lived up to initial expectations. Although the performance of these rubidium frequency standards has met and even exceeded GPS requirements, their reliability has not. The number of unscheduled outage times and the short operational lifetimes of the rubidium frequency standards compare poorly to the track record of the cesium frequency standards. Only a small number of rubidium frequency standards have actually been made operational. Of these, a large percentage have exhibited poor reliability. If this trend continues, it is unlikely that the rubidium frequency standards will help contribute to the navigation payload meeting program specification.

  1. Observations and Analysis of Mutual Events between the Uranus Main Satellites

    NASA Astrophysics Data System (ADS)

    Assafin, M.; Vieira-Martins, R.; Braga-Ribas, F.; Camargo, J. I. B.; da Silva Neto, D. N.; Andrei, A. H.

    2009-04-01

    Every 42 years, the Earth and the Sun pass through the plane of the orbits of the main satellites of Uranus. In these occasions, mutual occultations and eclipses between these bodies can be seen from the Earth. The current Uranus equinox from 2007 to 2009 offers a precious opportunity to observe these events. Here, we present the analysis of five occultations and two eclipses observed from Brazil during 2007. For the reduction of the CCD images, we developed a digital coronagraphic method that removed the planet's scattered light around the satellites. A simple geometric model of the occultation/eclipse was used to fit the observed light curves. Dynamical quantities such as the impact parameter, the relative speed, and the central time of the event were then obtained with precisions of 7.6 km, 0.18 km s-1, and 2.9 s, respectively. These results can be further used to improve the parameters of the dynamical theories of the main Uranus satellites. Based on observations made at Laboratório Nacional de Astrofísica (LNA), Itajubá-MG, Brazil.

  2. Evaluation of GOCE satellite gravimetry using BGI ground gravity observations over Africa, Asia and South America

    NASA Astrophysics Data System (ADS)

    Rexer, M. J.; Hirt, C.; Bonvalot, S.; Bruinsma, S.; Pail, R.; Kuhn, M.

    2013-12-01

    Launched in 2009, GOCE ('Gravity and Steady-state Ocean Circulation Explorer') satellite's gravity gradiometer gathered gravity observations which resulted in unprecedented global models of the Earth's gravity field at spatial scales up to 80 km. In remote regions and countries with sparsely distributed ground gravity observations the largest benefit through homogeneous GOCE observations is to be expected. This study deals with the evaluation of GOCE satellite data in those rather poorly surveyed areas with ground gravity data sets provided by the Bureau Gravimétrique International (BGI). We evaluate up-to-date GOCE gravity models at over 60,000 stations over parts of Africa, South America, Central and South-East Asia, and are able to give absolute accuracy estimates for GOCE models in respective areas and quantify the improvement due to GOCE with respect to current global gravity models containing terrestrial information (e.g. EGM2008). Our analysis is based on the spectral enhancement method (Hirt et al, 2011) where satellite data is augmented with terrestrial and forward-modelled gravity from topography prior to the comparisons with observed ground gravity.

  3. Statistical study of propagation characteristics of Pc1 pearl structures using conjugate ground-satellite observations

    NASA Astrophysics Data System (ADS)

    Jun, C. W.; Shiokawa, K.; Takahashi, K.; Paulson, K. W.; Schofield, I.; Connors, M. G.; Poddelskiy, I.; Shevtsov, B.; Kletzing, C.; Wygant, J. R.

    2015-12-01

    We investigated statistical characteristics of pearl structures (amplitude modulation) of Pc1 pulsations using conjugate observations with the ground induction magnetometers located at Athabasca (ATH, L = 4.3) in Canada and Magadan (MGD, L = 2.7) in Russia and the Van Allen Probes (RBSP-A and B) satellites located in the inner magnetosphere for a 1-year period (August 2012 to August 2013). We consider a ground magnetometer and a satellite to be conjugate when the satellite footprint is located within 1000 km of the ground magnetometer. From a survey of data acquired during the conjunction periods, we found 42 pearl Pc1events. These events were classified into four categories: structured Pc1 waves observed at both locations (9 events), structured Pc1 waves observed only on the ground (22 events) or in space (0 events), and unstructured Pc1 waves at both locations (11 events). We describe the spatial and temporal distributions of Pc1 pearl structures and their dependence on geomagnetic conditions. We also compare the frequency, the power ratio between space and ground, and the polarization among the four categories of events. In addition, we verified the similarity of Pc1 pearl structures between ground and space observations in order to investigate propagation and polarization characteristics of Pc1 pearl structures from the magnetosphere to the ionosphere.

  4. Cassini VIMS observations of the Galilean satellites including the VIMS calibration procedure

    USGS Publications Warehouse

    McCord, T.B.; Coradini, A.; Hibbitts, C.A.; Capaccioni, F.; Hansen, G.B.; Filacchione, G.; Clark, R.N.; Cerroni, P.; Brown, R.H.; Baines, K.H.; Bellucci, G.; Bibring, J.-P.; Buratti, B.J.; Bussoletti, E.; Combes, M.; Cruikshank, D.P.; Drossart, P.; Formisano, V.; Jaumann, R.; Langevin, Y.; Matson, D.L.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, C.

    2004-01-01

    The Visual and Infrared Mapping Spectrometer (VIMS) observed the Galilean satellites during the Cassini spacecraft's 2000/2001 flyby of Jupiter, providing compositional and thermal information about their surfaces. The Cassini spacecraft approached the jovian system no closer than about 126 Jupiter radii, about 9 million kilometers, at a phase angle of < 90 ??, resulting in only sub-pixel observations by VIMS of the Galilean satellites. Nevertheless, most of the spectral features discovered by the Near Infrared Mapping Spectrometer (NIMS) aboard the Galileo spacecraft during more than four years of observations have been identified in the VIMS data analyzed so far, including a possible 13C absorption. In addition, VIMS made observations in the visible part of the spectrum and at several new phase angles for all the Galilean satellites and the calculated phase functions are presented. In the process of analyzing these data, the VIMS radiometric and spectral calibrations were better determined in preparation for entry into the Saturn system. Treatment of these data is presented as an example of the VIMS data reduction, calibration and analysis process and a detailed explanation is given of the calibration process applied to the Jupiter data. ?? 2004 Elsevier Inc. All rights reserved.

  5. Evaluating Clouds, Aerosols, and their Interactions in Three Global Climate Models using COSP and Satellite Observations

    SciTech Connect

    Ban-Weiss, George; Jin, Ling; Bauer, S.; Bennartz, Ralph; Liu, Xiaohong; Zhang, Kai; Ming, Yi; Guo, Huan; Jiang, Jonathan

    2014-09-23

    Accurately representing aerosol-cloud interactions in global climate models is challenging. As parameterizations evolve, it is important to evaluate their performance with appropriate use of observations. In this work we compare aerosols, clouds, and their interactions in three climate models (AM3, CAM5, ModelE) to MODIS satellite observations. Modeled cloud properties were diagnosed using the CFMIP Observations Simulator Package (COSP). Cloud droplet number concentrations (N) were derived using the same algorithm for both satellite-simulated model values and observations. We find that aerosol optical depth tau simulated by models is similar to observations. For N, AM3 and CAM5 capture the observed spatial pattern of higher values in near-coast versus remote ocean regions, though modeled values in general are higher than observed. In contrast, ModelE simulates lower N in most near-coast versus remote regions. Aerosol- cloud interactions were computed as the sensitivity of N to tau for marine liquid clouds off the coasts of South Africa and Eastern Asia where aerosol pollution varies in time. AM3 and CAM5 are in most cases more sensitive than observations, while the sensitivity for ModelE is statistically insignificant. This widely used sensitivity could be subject to misinterpretation due to the confounding influence of meteorology on both aerosols and clouds. A simple framework for assessing the N – tau sensitivity at constant meteorology illustrates that observed sensitivity can change from positive to statistically insignificant when including the confounding influence of relative humidity. Satellite simulated values of N were compared to standard model output and found to be higher with a bias of 83 cm-3.

  6. Improving volcanic sulfur dioxide cloud dispersal forecasts by progressive assimilation of satellite observations

    NASA Astrophysics Data System (ADS)

    Boichu, Marie; Clarisse, Lieven; Khvorostyanov, Dmitry; Clerbaux, Cathy

    2014-04-01

    Forecasting the dispersal of volcanic clouds during an eruption is of primary importance, especially for ensuring aviation safety. As volcanic emissions are characterized by rapid variations of emission rate and height, the (generally) high level of uncertainty in the emission parameters represents a critical issue that limits the robustness of volcanic cloud dispersal forecasts. An inverse modeling scheme, combining satellite observations of the volcanic cloud with a regional chemistry-transport model, allows reconstructing this source term at high temporal resolution. We demonstrate here how a progressive assimilation of freshly acquired satellite observations, via such an inverse modeling procedure, allows for delivering robust sulfur dioxide (SO2) cloud dispersal forecasts during the eruption. This approach provides a computationally cheap estimate of the expected location and mass loading of volcanic clouds, including the identification of SO2-rich parts.

  7. Momentum Flux Estimates for South Georgia Island Mountain Waves in the Stratosphere Observed via Satellite

    NASA Technical Reports Server (NTRS)

    Alexander, M. Joan; Eckermann, Stephen D.; Broutman, Dave; Ma, Jun

    2009-01-01

    We show high-resolution satellite observations of mountain wave events in the stratosphere above South Georgia Island in the remote southern Atlantic Ocean and compute the wave momentum fluxes for these events. The fluxes are large, and they imply important drag forces on the circulation. Small island orography is generally neglected in mountain wave parameterizations used in global climate models because limited model resolution treats the grid cell containing the island as ocean rather than land. Our results show that satellite observations can be used to quantitatively constrain mountain wave momentum fluxes, and they suggest that mountain waves from island topography may be an important missing source of drag on the atmospheric circulation.

  8. Climate Model Diagnostic and Evaluation: With a Focus on Satellite Observations

    NASA Technical Reports Server (NTRS)

    Waliser, Duane

    2011-01-01

    Each year, we host a summer school that brings together the next generation of climate scientists - about 30 graduate students and postdocs from around the world - to engage with premier climate scientists from the Jet Propulsion Laboratory and elsewhere. Our yearly summer school focuses on topics on the leading edge of climate science research. Our inaugural summer school, held in 2011, was on the topic of "Using Satellite Observations to Advance Climate Models," and enabled students to explore how satellite observations can be used to evaluate and improve climate models. Speakers included climate experts from both NASA and the National Oceanic and Atmospheric Administration (NOAA), who provided updates on climate model diagnostics and evaluation and remote sensing of the planet. Details of the next summer school will be posted here in due course.

  9. Satellite observations of mesoscale features in lower Cook Inlet and Shelikof Strait, Gulf of Alaska

    NASA Technical Reports Server (NTRS)

    Schumacher, James D.; Barber, Willard E.; Holt, Benjamin; Liu, Antony K.

    1991-01-01

    The Seasat satellite launched in Summer 1978 carried a synthetic aperture radar (SAR). Although Seasat failed after 105 days in orbit, it provided observations that demonstrate the potential to examine and monitor upper oceanic processes. Seasat made five passes over lower Cook Inlet and Shelikof Strait, Alaska, during Summer 1978. SAR images from the passes show oceanographic features, including a meander in a front, a pair of mesoscale eddies, and internal waves. These features are compared with contemporary and representative images from a satellite-borne Advanced Very High Resolution Radiometer (AVHRR) and Coastal Zone Color Scanner (CZCS), with water property data, and with current observations from moored instruments. The results indicate that SAR data can be used to monitor mesoscale oceanographic features.

  10. Observations of power line harmonic radiation by the low-altitude AUREOL 3 satellite

    SciTech Connect

    Parrot, M.

    1994-03-01

    This paper presents observations of very low frequency radiation in the lower part of the ionosphere from a polar orbiting satellite at low latitudes. It was able to record several observation of low frequency radiation which is very close to a harmonic of the 50 Hz line frequency. The frequency is observed to drift in time, from 1 to 8 Hz/sec. They are not sure how to account for this apparent non-linear coupling of these very low frequency waves into the ionosphere.

  11. The global distribution of observed cloudiness - A contribution to the ISCCP. [International Satellite Cloud Climatology Project

    NASA Technical Reports Server (NTRS)

    London, Julius; Hahn, Carole J.; Warren, Stephen G.

    1989-01-01

    Satellite-inferred overall global cloud patterns generally corroborate those derived from ground-based observations. Both show significant differences of cloudiness between the two hemispheres and over extended land as compared with ocean areas. However, the averaged latitudinal values of surface-based observed cloud amounts are about 10 percent higher than those derived from Nimbus-7 observations. The largest difference (10-20 percent) is in the subtropics of each hemisphere and at subpolar and polar latitudes during the summer. The difference in reported average global total cloud amounts is about 10 percent.

  12. Hemispheric differences in PMC altitudes observed by the AIM satellite for the 2007/2008 seasons

    NASA Astrophysics Data System (ADS)

    Russell, J. M.; Bailey, S. M.; Gordley, L. L.; Hervig, M. E.; Stevens, M. H.; Thomas, G. E.; Rong, P.

    2008-05-01

    The Aeronomy of Ice in the Mesosphere (AIM) mission was launched from Vandenberg Air Force Base in California at 1:26:03 PDT on April 25, 2007 becoming the first satellite mission dedicated to the study of noctilucent clouds. A Pegasus XL rocket launched the satellite into a near perfect 600 km sun synchronous circular orbit providing an ideal injection for conducting AIM science studies. This paper focuses on hemispheric differences in polar mesospheric cloud (PMC) altitudes observed by the Solar Occultation For Ice Experiment (SOFIE) for the 2007 northern hemisphere season and the 2007/2008 southern hemisphere season. Results show PMC peak altitude differences of 1 km to 3 km depending on time in the season which is larger than previous ground-based and satellite results (~1 km). SOFIE data show that altitude differences are dependent on time within the season and that the differences are correlated with mesopause height. Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature data measured from the TIMED satellite over the 2003 to 2007 period show that hemispheric differences in the summer mesopause height were unusually large for part of the 2007 PMC season, consistent with the 3 km height difference in PMCs during that time.

  13. Micropulsations in the morning sector. II - Satellite observations of 10to 45-s waves at synchronous orbit, ATS 1

    NASA Technical Reports Server (NTRS)

    Arthur, C. W.; Mcpherron, R. L.

    1975-01-01

    A study of 13 wave events having 10- to 45-s periods and observed by ATS 1 in the morning sector reveals that these events, which have been called band-limited pulsations and are thought to be related to Pi 1, appear actually to be Pc 3. Digital power-spectral and coherency analysis was used to determine the characteristics of the wave activity. The average peak frequency of the events (about 0.04 Hz) and their generally narrow-band nature correspond closely with the characteristics of Pc 3. The local-time distribution of the events (peaking at 0900 LT) and their less than complete association with substorms also correspond more closely with Pc 3 characteristics. The orientation of the major axis of the polarization ellipse for these events was predominantly azimuthal, which agrees more closely with the east-west polarization of Pi 1 observed on the ground. However, some examples of radial orientation were observed in the satellite data.

  14. Astrometric observations of the faint satellites of Jupiter and minor planets, 1974-1977

    NASA Technical Reports Server (NTRS)

    Benedict, G. R.; Shelus, P. J.; Mulholland, J. D.

    1978-01-01

    Precise positions of the faint satellites VI-XII of Jupiter during the 1974 opposition, and for Jupiter XIII during the 1976-1977 and 1977-1978 oppositions, have been obtained from plates taken with the 2.1-m Otto Struve reflector of the McDonald Observatory by the use of a new quasi-automatic plate measurement and reduction procedure on a PDS microdensitometer. Observations of selected asteroids, including two of 1977 UB (Chiron) are given also.

  15. Arctic and Antarctic Sea Ice, 1978-1987: Satellite Passive-Microwave Observations and Analysis

    NASA Technical Reports Server (NTRS)

    Gloersen, Per; Campbell, William J.; Cavalieri, Donald J.; Comiso, Josefino C.; Parkinson, Claire L.; Zwally, H. Jay

    1992-01-01

    This book contains a description and analysis of the spatial and temporal variations in the Arctic and Antarctic sea ice covers from October 26, 1978 through August 20, 1987. It is based on data collected by the Scanning Multichannel Microwave Radiometer (SMMR) onboard the NASA Nimbus 7 satellite. The 8.8-year period, together with the 4 years of the Nimbus 5 Electrically Scanning Microwave Radiometer (ESMR) observations presented in two earlier volumes, comprises a sea ice record spanning almost 15 years.

  16. Introducing gravitational resonances from simple observations of Jupiter’s Galilean satellites

    NASA Astrophysics Data System (ADS)

    Ordonez-Etxeberria, I.; Sánchez-Lavega, A.; del Rio-Gaztelurrutia, T.

    2016-11-01

    We introduce a simple observation methodology to measure the orbital longitudes and mean motions of Jupiter Galilean satellites in order to verify the Laplace resonance phenomenon between Io, Europa and Ganymede (an orbital period commensurability 1:2:4 and an equation that relates their orbital longitudes). We complement the study with measurements of the quasi-commensurability 7:3 between the periods of Ganymede and Callisto, in order to further discuss gravitational resonances.

  17. Arctic Sea ice, 1973-1976: Satellite passive-microwave observations

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Comiso, Josefino C.; Zwally, H. Jay; Cavalieri, Donald J.; Gloersen, Per; Campbell, William J.

    1987-01-01

    The Arctic region plays a key role in the climate of the earth. The sea ice cover affects the radiative balance of the earth and radically changes the fluxes of heat between the atmosphere and the ocean. The observations of the Arctic made by the Electrically Scanning Microwave Radiometer (ESMR) on board the Nimbus 5 research satellite are summarized for the period 1973 through 1976.

  18. The degree of observability's analysis for satellite-to-user Orbiter Tracking System

    NASA Astrophysics Data System (ADS)

    Hu, X.

    1985-10-01

    Tracking schemes of the High Altitude Satellite to Low-Altitude User Orbiter Tracking (SOT) system are objectively appraised using the Degree of Observability (DOB) index. An extended Kalman filtering algorithm applicable to the SOT system for estimating the state of the user orbiter is given. A DOB method for analyzing the effects of various tracking schemes on the SOT system orbit determination accuracy is presented.

  19. Preparing for Routine Satellite Global Volcano Deformation Observations: The Volcano Deformation Database Task Force

    NASA Astrophysics Data System (ADS)

    Pritchard, M. E.; Jay, J.; Andrews, B. J.; Cooper, J.; Henderson, S. T.; Delgado, F.; Biggs, J.; Ebmeier, S. K.

    2014-12-01

    Satellite Interferometric Synthetic Aperture Radar (InSAR) has greatly expanded the number volcanoes that can be monitored for ground deformation - the number of known deforming volcanoes has increased almost five-fold since 1997 (to more than 213 volcanoes in 2014). However, from 1992-2014, there are still gaps in global volcano surveillance and only a fraction of the 1400 subaerial Holocene volcanoes have frequent observations in this time period. Starting in 2014, near global observations of volcano deformation should begin with the Sentinel satellites from the European Space Agency, ALOS-2 from the Japanese Space Agency, and eventually NISAR from the Indian Space Agency and NASA. With more frequent observations, more volcano deformation episodes are sure to be observed, but evaluating the significance of the observed deformation is not always straightforward -- how can we determine if deformation will lead to eruption? To answer this question, an international task force has been formed to create an inventory of volcano deformation events as part of the Global Volcano Model (http://globalvolcanomodel.org/gvm-task-forces/volcano-deformation-database/). We present the first results from our global study focusing on volcanoes that have few or no previous studies. In some cases, there is a lack of SAR data (for example, volcanoes of the South Sandwich Islands). For others, observations either show an absence of deformation or possible deformation that requires more data to be verified. An example of a deforming volcano that has few past studies is Pagan, an island in the Marianas Arc comprised of 2 stratovolcanoes within calderas. Our new InSAR measurements from both the ALOS and Envisat satellites show deformation near the 1981 May VEI 4 lava flow eruption on North Pagan at 2-3 cm/year between 2004-2010. Another example of a newly observed volcano is Karthala volcano in the Comoros. InSAR observations between 2004-2010 span four eruptions, only one of which is

  20. Ozone column content variability at the Kishinev site from satellite retrievals and ground observations

    NASA Astrophysics Data System (ADS)

    Aculinin, Alexandr; Smicov, Vladimir

    2010-05-01

    It is analyzed variability of the total ozone content (TOC) in column of atmosphere by using ozone retrievals from satellite platform and from direct ground observations at the Kishinev site, Moldova (47.00N; 28.56E). Direct ground observations of the TOC are regular carried out by Atmospheric Research Group (ARG), Institute of Applied Physics at the ground-based solar radiation monitoring station, Kishinev site, by using of hand-held ozonemeter MICROTOPS II. TOC measurements started since 2003. Data of ozone observations are presented at the research group web-site http://arg.phys.asm.md. Satellite TOC dataset at specific coordinates of Kishinev site was derived by using linear interpolation of the parent gridded databases from TOMS (1979-2004) and OMI (2005-2008) observations. It was established that relative difference of TOC between periods from 1979 to 1983 and from 2004 to 2008 was -5.16 %. Data were processed by applying of 5-year averaging "window". For a period from 1979 to 2008 statistical estimation of linear trend of the TOC was -2.08% per decade. Climatic norm of TOC for this period was equal to 335 DU. Variation of ozone column content at Kishinev site shows it seasonal character with maximum of the order of ~378 DU (in March and April) and with minimum of the order of ~289 DU (in October). The largest and lowest range of oscillations of monthly means of the TOC retrieved for Kishinev site from TOMS and OMI observations in the course of the period from 1979 to 2008 were ~ 102 DU (in February) and ~29 DU (in October). Extremely low and high values of the TOC ever registered for Kishinev site from TOMS and OMI observations were ~ 209 DU (on December 1, 1999) and ~ 532 DU (on March 3, 1988). It was shown that ARG ground observations give overestimated TOC values in comparison with the TOMS and OMI observations from satellite platforms. Relative differences or biases (in %) between satellite and ARG ground observations of the TOC at Kishinev site were

  1. Characterization of smoke aerosols over the Indochina Peninsula from multi-platform satellite observations

    NASA Astrophysics Data System (ADS)

    Jeong, M. J.; Hsu, N. Y. C.; Lee, J.; Sayer, A. M.; Bettenhausen, C.; Huang, J.

    2015-12-01

    Multi-faceted near-simultaneous observations from the sensors aboard multiple satellite platforms, so called the A-Train, are utilized to characterize the spatial distributions and the optical properties of smoke aerosols over the Indochina Peninsula. Observations from the A-Train sensors, especially, MODerate resolution Imaging Spectroradiometer (MODIS), Ozone Monitoring Instrument (OMI), and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), are synthesized to retrieve single-scattering albedo (SSA) and effective aerosol layer height (ALH) of BBS aerosols in the region. The retrieval algorithm extracts the absorption and height information about smoke aerosols, which is lumped into ultraviolet spectra at the top of the atmosphere, by taking the most reliable information contents that each satellite measurement can deliver. The results of retrieved SSA and ALH showed reasonable agreements with in-situ measurements, AEROsol Robotic NETwork (AERONET) data, and lidar-based observations. The uncertainty and sensitivity of the retrieval algorithm are also presented. The retrieved quantities are then used together with other satellite datasets to characterize the three-dimensional distributions of smoke aerosols over the Indochina Peninsular during the boreal spring time. Given the frequent horizontal collocations of smoke and clouds in the region, implication of smoke vertical distributions for long-range transports is also discussed. The results of this study are anticipated to advance our understanding on the climatic impacts of the smoke aerosols in the region.

  2. Stereographic observations from geosynchronous satellites - An important new tool for the atmospheric sciences

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.

    1981-01-01

    Observations of cloud geometry using scan-synchronized stereo geostationary satellites having images with horizontal spatial resolution of approximately 0.5 km, and temporal resolution of up to 3 min are presented. The stereo does not require a cloud with known emissivity to be in equilibrium with an atmosphere with a known vertical temperature profile. It is shown that absolute accuracies of about 0.5 km are possible. Qualitative and quantitative representations of atmospheric dynamics were shown by remapping, display, and stereo image analysis on an interactive computer/imaging system. Applications of stereo observations include: (1) cloud top height contours of severe thunderstorms and hurricanes, (2) cloud top and base height estimates for cloud-wind height assignment, (3) cloud growth measurements for severe thunderstorm over-shooting towers, (4) atmospheric temperature from stereo heights and infrared cloud top temperatures, and (5) cloud emissivity estimation. Recommendations are given for future improvements in stereo observations, including a third GOES satellite, operational scan synchronization of all GOES satellites and better resolution sensors.

  3. Combining Satellite Microwave Radiometer and Radar Observations to Estimate Atmospheric Latent Heating Profiles

    NASA Technical Reports Server (NTRS)

    Grecu, Mircea; Olson, William S.; Shie, Chung-Lin; L'Ecuyer, Tristan S.; Tao, Wei-Kuo

    2009-01-01

    In this study, satellite passive microwave sensor observations from the TRMM Microwave Imager (TMI) are utilized to make estimates of latent + eddy sensible heating rates (Q1-QR) in regions of precipitation. The TMI heating algorithm (TRAIN) is calibrated, or "trained" using relatively accurate estimates of heating based upon spaceborne Precipitation Radar (PR) observations collocated with the TMI observations over a one-month period. The heating estimation technique is based upon a previously described Bayesian methodology, but with improvements in supporting cloud-resolving model simulations, an adjustment of precipitation echo tops to compensate for model biases, and a separate scaling of convective and stratiform heating components that leads to an approximate balance between estimated vertically-integrated condensation and surface precipitation. Estimates of Q1-QR from TMI compare favorably with the PR training estimates and show only modest sensitivity to the cloud-resolving model simulations of heating used to construct the training data. Moreover, the net condensation in the corresponding annual mean satellite latent heating profile is within a few percent of the annual mean surface precipitation rate over the tropical and subtropical oceans where the algorithm is applied. Comparisons of Q1 produced by combining TMI Q1-QR with independently derived estimates of QR show reasonable agreement with rawinsonde-based analyses of Q1 from two field campaigns, although the satellite estimates exhibit heating profile structure with sharper and more intense heating peaks than the rawinsonde estimates. 2

  4. Classification of Clouds and Deep Convection from GEOS-5 Using Satellite Observations

    NASA Technical Reports Server (NTRS)

    Putman, William; Suarez, Max

    2010-01-01

    With the increased resolution of global atmospheric models and the push toward global cloud resolving models, the resemblance of model output to satellite observations has become strikingly similar. As we progress with our adaptation of the Goddard Earth Observing System Model, Version 5 (GEOS-5) as a high resolution cloud system resolving model, evaluation of cloud properties and deep convection require in-depth analysis beyond a visual comparison. Outgoing long-wave radiation (OLR) provides a sufficient comparison with infrared (IR) satellite imagery to isolate areas of deep convection. We have adopted a binning technique to generate a series of histograms for OLR which classify the presence and fraction of clear sky versus deep convection in the tropics that can be compared with a similar analyses of IR imagery from composite Geostationary Operational Environmental Satellite (GOES) observations. We will present initial results that have been used to evaluate the amount of deep convective parameterization required within the model as we move toward cloud system resolving resolutions of 10- to 1-km globally.

  5. Identification of weak autoionizing resonances observed through fluorescence from the satellite states of Ar{sup +}

    SciTech Connect

    McLaughlin, K.W.; Yenen, O.; Samson, J.A.R.

    1997-04-01

    Photoionization accompanied by excitation of the residual ionic state violates an independent electron model since, according to QED, photons interact only with individual electrons. By allowing measurements at a threshold event with high resolution, the observation of the fluorescence from the decay of these excited states (satellite states) is a sensitive method in the study of electron-electron interactions, providing complementary information to photoelectron spectroscopy. In the measurements reported here, an atomic beam of argon has been photoionized with 34 to 39 eV synchrotron radiation at beamline 9.0.1 of the Advanced Light Source. This energy range encompasses the 3p{sup 4} [{sup 3}P] 4p {sup 4}P, {sup 2}P, and {sup 2}D as well as the [{sup 1}D]4p {sup 2}F satellite states of Ar{sup +}. By observing the fine-structure resolved fluorescence from these satellite states, new Rydberg series and extensions of previously known series have been resolved with an energy resolution of 3 meV. With the high photon flux available from the high resolution monochromator of beamline 9.0.1, even the weakly excited [{sup 3}P] 4p ({sup 2}S) ns,d autoionizing structure has been observed for the first time.

  6. Can we observe and study the Mediterranean outflow and meddies from satellite remote sensing?

    NASA Astrophysics Data System (ADS)

    Yan, Xiao-Hai; Jo, Young-Heon; Liu, W. Timothy; He, Ming-Xia

    2004-02-01

    Previous studies of the Mediterranean outflow and meddies (O&M) were limited by poor spatial and temporal resolution of the conventional observations. Little is known about meddies formation and transport, and the spatial and temporal variation of its trajectories. Generally speaking, most of the satellite observations are confined to the ocean's surface or its surface layer, while meddies were located, on an average, at a depth of 1000m. We developed a new remote sensing method to observe and study the O&M through unique approaches in satellite multi-sensor data integration analyses. Satellite altimeter, scatterometer, SST and XBT data were used to detect and calculate the trajectories and the relative transport of the O&M. We found that more northwestward meddies occurred in the spring and more southward meddies occurred in the fall than previously thought. Since the O&M play a significant role in carrying salty water from the Mediterranean into the Atlantic and contribute to the North Atlantic Deep Water (NADW) formation, such new knowledge about their trajectories, transport and life histories is important to understand their mixing and interaction with the North Atlantic water, adn hence, to lead to a better understanding of the global ocean circulation and the global change.

  7. OBSERVATIONS AND ANALYSIS OF MUTUAL EVENTS BETWEEN THE URANUS MAIN SATELLITES

    SciTech Connect

    Assafin, M.; Vieira-Martins, R.; Braga-Ribas, F.; Camargo, J. I. B.; Da Silva Neto, D. N.; Andrei, A. H. E-mail: rvm@on.br

    2009-04-15

    Every 42 years, the Earth and the Sun pass through the plane of the orbits of the main satellites of Uranus. In these occasions, mutual occultations and eclipses between these bodies can be seen from the Earth. The current Uranus equinox from 2007 to 2009 offers a precious opportunity to observe these events. Here, we present the analysis of five occultations and two eclipses observed from Brazil during 2007. For the reduction of the CCD images, we developed a digital coronagraphic method that removed the planet's scattered light around the satellites. A simple geometric model of the occultation/eclipse was used to fit the observed light curves. Dynamical quantities such as the impact parameter, the relative speed, and the central time of the event were then obtained with precisions of 7.6 km, 0.18 km s{sup -1}, and 2.9 s, respectively. These results can be further used to improve the parameters of the dynamical theories of the main Uranus satellites.

  8. The ECLAIRs micro-satellite mission for gamma-ray burst multi-wavelength observations

    NASA Astrophysics Data System (ADS)

    Schanne, S.; Atteia, J.-L.; Barret, D.; Basa, S.; Boer, M.; Casse, F.; Cordier, B.; Daigne, F.; Klotz, A.; Limousin, O.; Manchanda, R.; Mandrou, P.; Mereghetti, S.; Mochkovitch, R.; Paltani, S.; Paul, J.; Petitjean, P.; Pons, R.; Ricker, G.; Skinner, G.

    2006-11-01

    Gamma-ray bursts (GRB)—at least those with a duration longer than a few seconds—are the most energetic events in the Universe and occur at cosmological distances. The ECLAIRs micro-satellite, to be launched in 2009, will provide multi-wavelength observations of GRB, to study their astrophysics and to use them as cosmological probes. Furthermore, in 2009 ECLAIRs is expected to be the only space-borne instrument capable of providing a GRB trigger in near real-time with sufficient localization accuracy for GRB follow-up observations with the powerful ground-based spectroscopic telescopes available by then. A “Phase A study” of the ECLAIRs project has recently been launched by the French Space Agency CNES, aiming at a detailed mission design and selection for flight in 2006. The ECLAIRs mission is based on a CNES micro-satellite of the “Myriade” family and dedicated ground-based optical telescopes. The satellite payload combines a 2 sr field-of-view coded aperture mask gamma-camera using 6400 CdTe pixels for GRB detection and localization with 10 arcmin precision in the 4 50 keV energy band, together with a soft X-ray camera for onboard position refinement to 1 arcmin. The ground-based optical robotic telescopes will detect the GRB prompt/early afterglow emission and localize the event to arcsec accuracy, for spectroscopic follow-up observations.

  9. Comparison of Satellite Observations of Aerosol Optical Depth to Surface Monitor Fine Particle Concentration

    NASA Technical Reports Server (NTRS)

    Kleb, Mary M.; AlSaadi, Jassim A.; Neil, Doreen O.; Pierce, Robert B.; Pippin, Margartet R.; Roell, Marilee M.; Kittaka, Chieko; Szykman, James J.

    2004-01-01

    Under NASA's Earth Science Applications Program, the Infusing satellite Data into Environmental Applications (IDEA) project examined the relationship between satellite observations and surface monitors of air pollutants to facilitate a more capable and integrated observing network. This report provides a comparison of satellite aerosol optical depth to surface monitor fine particle concentration observations for the month of September 2003 at more than 300 individual locations in the continental US. During September 2003, IDEA provided prototype, near real-time data-fusion products to the Environmental Protection Agency (EPA) directed toward improving the accuracy of EPA s next-day Air Quality Index (AQI) forecasts. Researchers from NASA Langley Research Center and EPA used data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument combined with EPA ground network data to create a NASA-data-enhanced Forecast Tool. Air quality forecasters used this tool to prepare their forecasts of particle pollution, or particulate matter less than 2.5 microns in diameter (PM2.5), for the next-day AQI. The archived data provide a rich resource for further studies and analysis. The IDEA project uses data sets and models developed for tropospheric chemistry research to assist federal, state, and local agencies in making decisions concerning air quality management to protect public health.

  10. Long-Term Trends Worldwide in Ambient NO2 Concentrations Inferred from Satellite Observations

    PubMed Central

    Geddes, Jeffrey A.; Martin, Randall V.; Boys, Brian L.; van Donkelaar, Aaron

    2015-01-01

    Background Air pollution is associated with morbidity and premature mortality. Satellite remote sensing provides globally consistent decadal-scale observations of ambient nitrogen dioxide (NO2) pollution. Objective We determined global population-weighted annual mean NO2 concentrations from 1996 through 2012. Methods We used observations of NO2 tropospheric column densities from three satellite instruments in combination with chemical transport modeling to produce a global 17-year record of ground-level NO2 at 0.1° × 0.1° resolution. We calculated linear trends in population-weighted annual mean NO2 (PWMNO2) concentrations in different regions around the world. Results We found that PWMNO2 in high-income North America (Canada and the United States) decreased more steeply than in any other region, having declined at a rate of –4.7%/year [95% confidence interval (CI): –5.3, –4.1]. PWMNO2 decreased in western Europe at a rate of –2.5%/year (95% CI: –3.0, –2.1). The highest PWMNO2 occurred in high-income Asia Pacific (predominantly Japan and South Korea) in 1996, with a subsequent decrease of –2.1%/year (95% CI: –2.7, –1.5). In contrast, PWMNO2 almost tripled in East Asia (China, North Korea, and Taiwan) at a rate of 6.7%/year (95% CI: 6.0, 7.3). The satellite-derived estimates of trends in ground-level NO2 were consistent with regional trends inferred from data obtained from ground-station monitoring networks in North America (within 0.7%/year) and Europe (within 0.3%/year). Our rankings of regional average NO2 and long-term trends differed from the satellite-derived estimates of fine particulate matter reported elsewhere, demonstrating the utility of both indicators to describe changing pollutant mixtures. Conclusions Long-term trends in satellite-derived ambient NO2 provide new information about changing global exposure to ambient air pollution. Our estimates are publicly available at http://fizz.phys.dal.ca/~atmos/martin/?page_id=232. Citation

  11. Paddy field mapping and yield estimation by satellite imagery and in situ observations

    NASA Astrophysics Data System (ADS)

    Oyoshi, K.; Sobue, S.

    2011-12-01

    Since Asian countries are responsible for approximately 90% of the world rice production and consumptions, rice is the most significant cereal crop in Asia. In order to ensure food security and take mitigation strategies or policies to manage food shortages, timely and accurate statistics of rice production are essential. It is time and cost consuming work to create accurate statistics of rice production by ground-based measurements. Hence, satellite remote sensing is expected to contribute food security through the systematic collection of food security related information such as crop growth or yield estimation. In 2011, Japan Aerospace Exploration Agency (JAXA) is collaborating with GISTDA (Geo-Informatics and Space Technology Development Agency, Thailand) in research projects of rice yield estimation by integrating satellite imagery and in situ data. Thailand is one of the largest rice production countries and the largest rice exporting country, therefore rice related statistics are imperative for food security and economy in the country. However, satellite observation by optical sensor in tropics including Thailand is highly limited, because the area is frequently covered by cloud. In contrast, Japanese microwave sensor, namely Phased-Array L-Band Synthetic Aperture Radar (PALSAR) on board Advanced Land Observing Satellite (ALOS) is suitable for monitoring cloudy area such as Southeast Asia, because PALSAR can penetrate clouds and collect land-surface information even if the area is covered by cloud. In this study, rice crop yield over Khon Kaen, northeast part of Thailand was estimated by combining satellite imagery and in-situ observation. This study consists of mainly two parts, paddy field mapping and yield estimation by numerical crop model. First, paddy field areas were detected by integrating PALSAR and AVNIR-2 data. PALSAR imagery has much speckle noise and the border of each landcover is ambiguous compared to that of optical sensor. To overcome this

  12. POD experiments using real and simulated time-sharing observations for GEO satellites in C-band transfer ranging system

    NASA Astrophysics Data System (ADS)

    Fen, Cao; XuHai, Yang; ZhiGang, Li; ChuGang, Feng

    2016-08-01

    The normal consecutive observing model in Chinese Area Positioning System (CAPS) can only supply observations of one GEO satellite in 1 day from one station. However, this can't satisfy the project need for observing many GEO satellites in 1 day. In order to obtain observations of several GEO satellites in 1 day like GPS/GLONASS/Galileo/BeiDou, the time-sharing observing model for GEO satellites in CAPS needs research. The principle of time-sharing observing model is illuminated with subsequent Precise Orbit Determination (POD) experiments using simulated time-sharing observations in 2005 and the real time-sharing observations in 2015. From time-sharing simulation experiments before 2014, the time-sharing observing 6 GEO satellites every 2 h has nearly the same orbit precision with the consecutive observing model. From POD experiments using the real time-sharing observations, POD precision for ZX12# and Yatai7# are about 3.234 m and 2.570 m, respectively, which indicates the time-sharing observing model is appropriate for CBTR system and can realize observing many GEO satellites in 1 day.

  13. Observational detection of eclipses of J5 Amalthea by the Galilean satellites

    NASA Astrophysics Data System (ADS)

    Christou, A. A.; Lewis, F.; Roche, P.; Hidas, M. G.; Brown, T. M.

    2010-11-01

    Aims: We carried out observations of the small jovian satellite Amalthea (J5) as it was being eclipsed by the Galilean satellites near the 2009 equinox of Jupiter in order to apply the technique of mutual event photometry to the astrometric determination of this satellite's position. Methods: The observations were carried out during the period 06/2009-09/2009 from the island of Maui, Hawaii and Siding Spring, Australia with the 2m Faulkes Telescopes North and South respectively. We observed in the near-infrared part of the spectrum using a PanStarrs-Z filter with Jupiter near the edge of the field in order to mitigate against the glare from the planet. Frames were acquired at rates > 1/min during eclipse times predicted using recent JPL ephemerides for the satellites. Following subtraction of the sky background from these frames, differential aperture photometry was carried out on Amalthea and a nearby field star. Results: We have obtained three lightcurves which show a clear drop in the flux from Amalthea, indicating that an eclipse took place as predicted. These were model-fitted to yield best estimates of the time of maximum flux drop and the impact parameter. These are consistent with Amalthea's ephemeris but indicate that Amalthea is slightly ahead of, and closer to Jupiter than, its predicted position by approximately half the ephemeris uncertainty in these directions. We argue that a ground-based campaign of higher-cadence photometry accurate at the 5% level or better during the next season of eclipses in 2014-15 should yield positions to within 0.05 arcsec and affect a corresponding improvement in Amalthea's ephemeris.

  14. Satellite observations of the QBO wave driving by Kelvin waves and gravity waves

    NASA Astrophysics Data System (ADS)

    Ern, Manfred; Preusse, Peter; Kalisch, Silvio; Riese, Martin

    2014-05-01

    The quasi-biennial oscillation (QBO) of the zonal wind in the tropical stratosphere is an important process in atmospheric dynamics influencing a wide range of altitudes and latitudes. Effects of the QBO are found also in the mesosphere and in the extra-tropics. The QBO even has influence on the surface weather and climate, for example during winter in the northern hemisphere at midlatitudes. Still, climate models have large difficulties in reproducing a realistic QBO. One reason for this deficiency are uncertainties in the wave driving by planetary waves and, in particular, gravity waves that are usually too small-scale to be resolved in global models. Different global equatorial wave modes (e.g., Kelvin waves) have been identified by longitude-time 2D spectral analysis in Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite temperature data, as well as ECMWF temperatures. We find good agreement between SABER satellite observations and ECMWF wave variances in both QBO-related temporal variations and their magnitude. Slow phase speed waves are strongly modulated by the QBO, higher phase speed waves are almost unaffected by the QBO, and ultra-fast equatorial waves can even reach the MLT region. Momentum fluxes and zonal wind drag due to Kelvin waves are derived, and the relative contribution of Kelvin waves to the QBO wind reversal from westward to eastward wind is estimated to be about 30% of the total wave driving. This is in good agreement with the general assumption that gravity waves (GWs) are probably more important for the QBO driving than global-scale waves. This is further supported by SABER and High Resolution Dynamics Limb Sounder (HIRDLS) satellite observations of gravity wave drag in the equatorial region. These observations are compared with the drag still missing in the ECMWF ERA Interim (ERAI) tropical momentum budget after considering zonal wind tendency, Coriolis force, advection terms and drag of resolved global

  15. Coupling rainfall observations and satellite soil moisture for predicting event soil loss in Central Italy

    NASA Astrophysics Data System (ADS)

    Todisco, Francesca; Brocca, Luca; Termite, Loris Francesco; Wagner, Wolfgang

    2015-04-01

    The accuracy of water soil loss prediction depends on the ability of the model to account for effects of the physical phenomena causing the output and the accuracy by which the parameters have been determined. The process based models require considerable effort to obtain appropriate parameter values and their failure to produce better results than achieved using the USLE/RUSLE model, encourages the use of the USLE/RUSLE model in roles of which it was not designed. In particular it is widely used in watershed models even at the event temporal scale. At hillslope scale, spatial variability in soil and vegetation result in spatial variations in soil moisture and consequently in runoff within the area for which soil loss estimation is required, so the modeling approach required to produce those estimates needs to be sensitive to those spatial variations in runoff. Some models include explicit consideration of runoff in determining the erosive stresses but this increases the uncertainty of the prediction due to the difficulty in parameterising the models also because the direct measures of surface runoff are rare. The same remarks are effective also for the USLE/RUSLE models including direct consideration of runoff in the erosivity factor (i.e. USLE-M by Kinnell and Risse, 1998, and USLE-MM by Bagarello et al., 2008). Moreover actually most of the rainfall-runoff models are based on the knowledge of the pre-event soil moisture that is a fundamental variable in the rainfall-runoff transformation. In addiction soil moisture is a readily available datum being possible to have easily direct pre-event measures of soil moisture using in situ sensors or satellite observations at larger spatial scale; it is also possible to derive the antecedent water content with soil moisture simulation models. The attempt made in the study is to use the pre-event soil moisture to account for the spatial variation in runoff within the area for which the soil loss estimates are required. More

  16. Determination of the plasmapause boundary using ground magnetometer field line resonances, satellite observations, and modeling

    NASA Astrophysics Data System (ADS)

    Zesta, E.; Boudouridis, A.; Jorgensen, A. M.; Yizengaw, E.; Chi, P. J.; Moldwin, M.; Carranza, T.; Mann, I. R.; Johnston, W. R.; Wilson, G. R.

    2012-12-01

    The plasmapause boundary layer (PBL) separates the cold and dense plasmaspheric plasma from the more tenuous and hot plasma sheet plasma and organizes the spatial distribution of ULF and VLF waves that can contribute to acceleration or loss processes of radiation belt particles through wave-particle interactions. The PBL has been traditionally determined by in situ observations and can be given by empirical models. Recent work has shown that a mid-latitude chain of well-spaced ground magnetometers can also determine the PBL boundary location. Spectral properties, like the cross-phase reversal between two stations closely aligned in latitude, have been shown to indicate the presence of a sharp PBL. We show here an example of such a PBL identification during the moderate storm of Nov 9-12, 2006. We combine observations from the SAMBA (South American Meridional B-field Array), MEASURE (Magnetometers along the Eastern Atlantic Seaboard for Undergraduate Research and Education), McMAC (Mid-continent Magnetoseismic Chain), and CARISMA ground magnetometer chains covering L values from L=2 to L=5 to statistically determine how commonly the PBL is determined from ground magnetometers. In our initial study we examine observations from June to December, 2006. We compare our PBL determinations with the determination of the same boundary from the Defense Meteorological Satellite Program (DMSP) satellites, based on the H+ density observations, which have been shown to accurately identify the PBL from a low-Earth orbiting satellite. We also compare our PBL identification with those determined from a global GPS TEC map and GPS TEC tomography technique used by a chain of ground GPS receivers. Finally, we compare our observations with results from the Dynamic Global Core Plasma Model (DGCPM), as well as existing empirical models based on in situ observations.

  17. Review: advances in in situ and satellite phenological observations in Japan.

    PubMed

    Nagai, Shin; Nasahara, Kenlo Nishida; Inoue, Tomoharu; Saitoh, Taku M; Suzuki, Rikie

    2016-04-01

    To accurately evaluate the responses of spatial and temporal variation of ecosystem functioning (evapotranspiration and photosynthesis) and services (regulating and cultural services) to the rapid changes caused by global warming, we depend on long-term, continuous, near-surface, and satellite remote sensing of phenology over wide areas. Here, we review such phenological studies in Japan and discuss our current knowledge, problems, and future developments. In contrast with North America and Europe, Japan has been able to evaluate plant phenology along vertical and horizontal gradients within a narrow area because of the country's high topographic relief. Phenological observation networks that support scientific studies and outreach activities have used near-surface tools such as digital cameras and spectral radiometers. Differences in phenology among ecosystems and tree species have been detected by analyzing the seasonal variation of red, green, and blue digital numbers (RGB values) extracted from phenological images, as well as spectral reflectance and vegetation indices. The relationships between seasonal variations in RGB-derived indices or spectral characteristics and the ecological and CO2 flux measurement data have been well validated. In contrast, insufficient satellite remote-sensing observations have been conducted because of the coarse spatial resolution of previous datasets, which could not detect the heterogeneous plant phenology that results from Japan's complex topography and vegetation. To improve Japanese phenological observations, multidisciplinary analysis and evaluation will be needed to link traditional phenological observations with "index trees," near-surface and satellite remote-sensing observations, "citizen science" (observations by citizens), and results published on the Internet.

  18. Review: advances in in situ and satellite phenological observations in Japan

    NASA Astrophysics Data System (ADS)

    Nagai, Shin; Nasahara, Kenlo Nishida; Inoue, Tomoharu; Saitoh, Taku M.; Suzuki, Rikie

    2016-04-01

    To accurately evaluate the responses of spatial and temporal variation of ecosystem functioning (evapotranspiration and photosynthesis) and services (regulating and cultural services) to the rapid changes caused by global warming, we depend on long-term, continuous, near-surface, and satellite remote sensing of phenology over wide areas. Here, we review such phenological studies in Japan and discuss our current knowledge, problems, and future developments. In contrast with North America and Europe, Japan has been able to evaluate plant phenology along vertical and horizontal gradients within a narrow area because of the country's high topographic relief. Phenological observation networks that support scientific studies and outreach activities have used near-surface tools such as digital cameras and spectral radiometers. Differences in phenology among ecosystems and tree species have been detected by analyzing the seasonal variation of red, green, and blue digital numbers (RGB values) extracted from phenological images, as well as spectral reflectance and vegetation indices. The relationships between seasonal variations in RGB-derived indices or spectral characteristics and the ecological and CO2 flux measurement data have been well validated. In contrast, insufficient satellite remote-sensing observations have been conducted because of the coarse spatial resolution of previous datasets, which could not detect the heterogeneous plant phenology that results from Japan's complex topography and vegetation. To improve Japanese phenological observations, multidisciplinary analysis and evaluation will be needed to link traditional phenological observations with "index trees," near-surface and satellite remote-sensing observations, "citizen science" (observations by citizens), and results published on the Internet.

  19. Assimilating multi-sensor satellite observations for initializing hydrologic and agricultural forecasts

    NASA Astrophysics Data System (ADS)

    Andreadis, Konstantinos; Das, Narendra; Granger, Stephanie; Han, Eunjin; Ines, Amor; Stampoulis, Dimitrios

    2015-04-01

    The application of data assimilation techniques in hydrologic studies has been gaining traction in the last 10-15 years. Most of these studies have focused on a single water cycle component, while few studies have examined methods of assimilating multiple observations from different sensors and of different hydrologic variables. The latter is challenging since any potential disparities in the observations could lead to suboptimal estimates after assimilation. The optimal estimates of hydrologic states, such as soil moisture, can be used as initial conditions for hydrologic forecasting systems. A multi-sensor and multivariate data assimilation forecast system has been developed at JPL (RHEAS, Regional Hydrologic Extremes Assessment System) with an initial focus on forecasting drought characteristics. The core of RHEAS is the VIC hydrology model, which has been widely used for many water resources applications. Apart from hydrologic forecasts, RHEAS can produce agricultural forecasts by coupling VIC with the DSSAT crop growth model. The modeling system is supported by a spatial database component, which provides access to multiple in-situ and satellite observations and allows data to be delivered to users through web-GIS or mobile application interfaces. The satellite observations, which include soil moisture, water storage, evapotranspiration, and snow cover, are assimilated into the VIC model to update the initial state of seasonal hydrologic and crop growth forecasts. We demonstrate the value of ingesting satellite observations by performing a series of hindcast experiments over both the United States (California and Upper Colorado basins) and Kenya (Nzoia basin). In-situ measurements along with a simulation with the best available datasets are used as the benchmark to evaluate the hindcasts against. The impact of each observation type or sensor is quantified, allowing for evaluating their relative contribution to improving the forecast skill. Particular case

  20. Assimilating multi-sensor satellite observations for initializing hydrologic and agricultural forecasts

    NASA Astrophysics Data System (ADS)

    Andreadis, K.; Stampoulis, D.; Das, N. N.; Granger, S. L.; Ines, A.; Han, E.

    2015-12-01

    The application of data assimilation techniques in hydrologic studies has been gaining traction in the last 10-15 years. Most of these studies have focused on a single water cycle component, while few studies have examined methods of assimilating multiple observations from different sensors and of different hydrologic variables. The latter is challenging since any potential disparities in the observations could lead to suboptimal estimates after assimilation. The optimal estimates of hydrologic states, such as soil moisture, can be used as initial conditions for hydrologic forecasting systems. A multi-sensor and multivariate data assimilation forecast system has been developed at JPL (RHEAS, Regional Hydrologic Extremes Assessment System) with an initial focus on forecasting drought characteristics. The core of RHEAS is the VIC hydrology model, which has been widely used for many water resources applications. Apart from hydrologic forecasts, RHEAS can produce agricultural forecasts by coupling VIC with the DSSAT crop growth model. The modeling system is supported by a spatial database component, which provides access to multiple in-situ and satellite observations and allows data to be delivered to users through web-GIS or mobile application interfaces. The satellite observations, which include soil moisture, water storage, evapotranspiration, and snow cover, are assimilated into the VIC model to update the initial state of seasonal hydrologic and crop growth forecasts. We demonstrate the value of ingesting satellite observations by performing a series of hindcast experiments over both the United States (California and Upper Colorado basins) and Kenya (Nzoia basin). In-situ measurements along with a simulation with the best available datasets are used as the benchmark to evaluate the hindcasts against. The impact of each observation type or sensor is quantified, allowing for evaluating their relative contribution to improving the forecast skill. Particular case

  1. Review: advances in in situ and satellite phenological observations in Japan.

    PubMed

    Nagai, Shin; Nasahara, Kenlo Nishida; Inoue, Tomoharu; Saitoh, Taku M; Suzuki, Rikie

    2016-04-01

    To accurately evaluate the responses of spatial and temporal variation of ecosystem functioning (evapotranspiration and photosynthesis) and services (regulating and cultural services) to the rapid changes caused by global warming, we depend on long-term, continuous, near-surface, and satellite remote sensing of phenology over wide areas. Here, we review such phenological studies in Japan and discuss our current knowledge, problems, and future developments. In contrast with North America and Europe, Japan has been able to evaluate plant phenology along vertical and horizontal gradients within a narrow area because of the country's high topographic relief. Phenological observation networks that support scientific studies and outreach activities have used near-surface tools such as digital cameras and spectral radiometers. Differences in phenology among ecosystems and tree species have been detected by analyzing the seasonal variation of red, green, and blue digital numbers (RGB values) extracted from phenological images, as well as spectral reflectance and vegetation indices. The relationships between seasonal variations in RGB-derived indices or spectral characteristics and the ecological and CO2 flux measurement data have been well validated. In contrast, insufficient satellite remote-sensing observations have been conducted because of the coarse spatial resolution of previous datasets, which could not detect the heterogeneous plant phenology that results from Japan's complex topography and vegetation. To improve Japanese phenological observations, multidisciplinary analysis and evaluation will be needed to link traditional phenological observations with "index trees," near-surface and satellite remote-sensing observations, "citizen science" (observations by citizens), and results published on the Internet. PMID:26307639

  2. Coupling rainfall observations and satellite soil moisture for predicting event soil loss in Central Italy

    NASA Astrophysics Data System (ADS)

    Todisco, Francesca; Brocca, Luca; Termite, Loris Francesco; Wagner, Wolfgang

    2015-04-01

    The accuracy of water soil loss prediction depends on the ability of the model to account for effects of the physical phenomena causing the output and the accuracy by which the parameters have been determined. The process based models require considerable effort to obtain appropriate parameter values and their failure to produce better results than achieved using the USLE/RUSLE model, encourages the use of the USLE/RUSLE model in roles of which it was not designed. In particular it is widely used in watershed models even at the event temporal scale. At hillslope scale, spatial variability in soil and vegetation result in spatial variations in soil moisture and consequently in runoff within the area for which soil loss estimation is required, so the modeling approach required to produce those estimates needs to be sensitive to those spatial variations in runoff. Some models include explicit consideration of runoff in determining the erosive stresses but this increases the uncertainty of the prediction due to the difficulty in parameterising the models also because the direct measures of surface runoff are rare. The same remarks are effective also for the USLE/RUSLE models including direct consideration of runoff in the erosivity factor (i.e. USLE-M by Kinnell and Risse, 1998, and USLE-MM by Bagarello et al., 2008). Moreover actually most of the rainfall-runoff models are based on the knowledge of the pre-event soil moisture that is a fundamental variable in the rainfall-runoff transformation. In addiction soil moisture is a readily available datum being possible to have easily direct pre-event measures of soil moisture using in situ sensors or satellite observations at larger spatial scale; it is also possible to derive the antecedent water content with soil moisture simulation models. The attempt made in the study is to use the pre-event soil moisture to account for the spatial variation in runoff within the area for which the soil loss estimates are required. More

  3. Minimum Number of Observation Points for LEO Satellite Orbit Estimation by OWL Network

    NASA Astrophysics Data System (ADS)

    Park, Maru; Jo, Jung Hyun; Cho, Sungki; Choi, Jin; Kim, Chun-Hwey; Park, Jang-Hyun; Yim, Hong-Suh; Choi, Young-Jun; Moon, Hong-Kyu; Bae, Young-Ho; Park, Sun-Youp; Kim, Ji-Hye; Roh, Dong-Goo; Jang, Hyun-Jung; Park, Young-Sik; Jeong, Min-Ji

    2015-12-01

    By using the Optical Wide-field Patrol (OWL) network developed by the Korea Astronomy and Space Science Institute (KASI) we generated the right ascension and declination angle data from optical observation of Low Earth Orbit (LEO) satellites. We performed an analysis to verify the optimum number of observations needed per arc for successful estimation of orbit. The currently functioning OWL observatories are located in Daejeon (South Korea), Songino (Mongolia), and Oukaïmeden (Morocco). The Daejeon Observatory is functioning as a test bed. In this study, the observed targets were Gravity Probe B, COSMOS 1455, COSMOS 1726, COSMOS 2428, SEASAT 1, ATV-5, and CryoSat-2 (all in LEO). These satellites were observed from the test bed and the Songino Observatory of the OWL network during 21 nights in 2014 and 2015. After we estimated the orbit from systematically selected sets of observation points (20, 50, 100, and 150) for each pass, we compared the difference between the orbit estimates for each case, and the Two Line Element set (TLE) from the Joint Space Operation Center (JSpOC). Then, we determined the average of the difference and selected the optimal observation points by comparing the average values.

  4. Comparison of radiances observed from satellite and aircraft with calculations by using two atmospheric transmittance models.

    PubMed

    Murty, D G; Smith, W L; Woolf, H M; Hayden, C M

    1993-03-20

    An evaluation of two different atmospheric transmittance models is performed by using radiance data from the high-resolution infraRed Sounder (HIRS) instrument onboard the National Oceanic and Atmospheric Administration's NOAA-9 satellite and the airborne high-resolution interferometer sounder (HIS) instrument. Synthetic radiances have been derived from collocated radiosondes by using the television infrared observation satellite (TIROS) operational vertical sounder (TOVS) operational transmittance model and the fast atmospheric signature code (FASCOD2) line-by-line transmittance model for comparison with the two independent instrument observations. Radiance observations in various spectral channels from the HIRS and HIS instruments along with the synthetic radiances derived from the FASCOD2 and operational TOVS transmittance models are used for the performance evaluation. The results of the comparison reveal a significant discrepancy between 707 and 717 cm(-l) in the radiance calculation for both models. Exce llent agreement is observed between observation and calculation for the lower tropospheric long-wave temperature sounding channels. Serious problems are noted with the modeling of water vapor in the operational TOVS transmittance model. In addition, poor performance by FASCOD2 is revealed for the short-wavelength N(2)O-CO(2) HIRS spectral channels. In general the operational TOVS transmittance model is found to be only slightly inferior to the FASCOD2 model. Regarding the performance of the instruments, observations from the NOAA-9 HIRS and the aircraft HIS are comparable in terms of their agreement with theoretical computations.

  5. Satellite observations and modeling of oil spill trajectories in the Bohai Sea.

    PubMed

    Xu, Qing; Li, Xiaofeng; Wei, Yongliang; Tang, Zeyan; Cheng, Yongcun; Pichel, William G

    2013-06-15

    On June 4 and 17, 2011, separate oil spill accidents occurred at two oil platforms in the Bohai Sea, China. The oil spills were subsequently observed on different types of satellite images including SAR (Synthetic Aperture Radar), Chinese HJ-1-B CCD and NASA MODIS. To illustrate the fate of the oil spills, we performed two numerical simulations to simulate the trajectories of the oil spills with the GNOME (General NOAA Operational Modeling Environment) model. For the first time, we drive the GNOME with currents obtained from an operational ocean model (NCOM, Navy Coastal Ocean Model) and surface winds from operational scatterometer measurements (ASCAT, the Advanced Scatterometer). Both data sets are freely and openly available. The initial oil spill location inputs to the model are based on the detected oil spill locations from the SAR images acquired on June 11 and 14. Three oil slicks are tracked simultaneously and our results show good agreement between model simulations and subsequent satellite observations in the semi-enclosed shallow sea. Moreover, GNOME simulation shows that the number of 'splots', which denotes the extent of spilled oil, is a vital factor for GNOME running stability when the number is less than 500. Therefore, oil spill area information obtained from satellite sensors, especially SAR, is an important factor for setting up the initial model conditions. PMID:23618498

  6. Satellite observations and modeling of oil spill trajectories in the Bohai Sea.

    PubMed

    Xu, Qing; Li, Xiaofeng; Wei, Yongliang; Tang, Zeyan; Cheng, Yongcun; Pichel, William G

    2013-06-15

    On June 4 and 17, 2011, separate oil spill accidents occurred at two oil platforms in the Bohai Sea, China. The oil spills were subsequently observed on different types of satellite images including SAR (Synthetic Aperture Radar), Chinese HJ-1-B CCD and NASA MODIS. To illustrate the fate of the oil spills, we performed two numerical simulations to simulate the trajectories of the oil spills with the GNOME (General NOAA Operational Modeling Environment) model. For the first time, we drive the GNOME with currents obtained from an operational ocean model (NCOM, Navy Coastal Ocean Model) and surface winds from operational scatterometer measurements (ASCAT, the Advanced Scatterometer). Both data sets are freely and openly available. The initial oil spill location inputs to the model are based on the detected oil spill locations from the SAR images acquired on June 11 and 14. Three oil slicks are tracked simultaneously and our results show good agreement between model simulations and subsequent satellite observations in the semi-enclosed shallow sea. Moreover, GNOME simulation shows that the number of 'splots', which denotes the extent of spilled oil, is a vital factor for GNOME running stability when the number is less than 500. Therefore, oil spill area information obtained from satellite sensors, especially SAR, is an important factor for setting up the initial model conditions.

  7. Advances in Assimilation of Satellite-Based Passive Microwave Observations for Soil-Moisture Estimation

    NASA Technical Reports Server (NTRS)

    De Lannoy, Gabrielle J. M.; Pauwels, Valentijn; Reichle, Rolf H.; Draper, Clara; Koster, Randy; Liu, Qing

    2012-01-01

    Satellite-based microwave measurements have long shown potential to provide global information about soil moisture. The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS, [1]) mission as well as the future National Aeronautics and Space Administration (NASA) Soil Moisture Active and Passive (SMAP, [2]) mission measure passive microwave emission at L-band frequencies, at a relatively coarse (40 km) spatial resolution. In addition, SMAP will measure active microwave signals at a higher spatial resolution (3 km). These new L-band missions have a greater sensing depth (of -5cm) compared with past and present C- and X-band microwave sensors. ESA currently also disseminates retrievals of SMOS surface soil moisture that are derived from SMOS brightness temperature observations and ancillary data. In this research, we address two major challenges with the assimilation of recent/future satellite-based microwave measurements: (i) assimilation of soil moisture retrievals versus brightness temperatures for surface and root-zone soil moisture estimation and (ii) scale-mismatches between satellite observations, models and in situ validation data.

  8. Solar Irradiance observation from Fengyun3 meteorological satellites: recent results and future plan

    NASA Astrophysics Data System (ADS)

    Qi, Jin; Zhang, Peng; Qiu, Hong; Fang, Wei

    2016-04-01

    The Solar Irradiance Monitors (SIM) on-board Fengyun3 (FY3) satellites have been observing Total Solar Irradiance since June 2008. With the lessons from the first two satellites, the SIM on FY3C has two significant improvements by adding sun tracing system and temperature control system, which is named after SIM-II. The SIM-II measurements are first really traceable to World Radiometric Reference and building an on-orbit aging model. TSI from FY3C/SIM-II has been evaluated by comparing with SORCE/TIM and RMIB composite data. The result shows a good consistency. Monitoring of strong solar activity during Oct. 2014, FY3C/SIM-II and SORCE/TIM showed the similar result about solar energy change. For the future plan, we would like to have cooperation with RMIB and PMOD on TSI observation from FY3 early-morning orbit satellite which is designed to launch in 2018. We also plan to develop a new ability to capture daily variance in solar spectral irradiance on the early-morning orbit.

  9. Satellite Observation of El Nino Effects on Amazon Forest Phenology and Productivity

    NASA Technical Reports Server (NTRS)

    Asner, Gregory P.; Townsend, Alan R.; Braswell, Bobby H.

    2000-01-01

    Climate variability may affect the functioning of Amazon moist tropical forests, and recent modeling analyses suggest that the carbon dynamics of the region vary interannually in response to precipitation and temperature anomalies. However, due to persistent orbital and atmospheric artifacts in the satellite record, remote sensing observations have not provided quantitative evidence that climate variation affects Amazon forest phenology or productivity, We developed a method to minimize and quantify non-biological artifacts in NOAA AVHRR satellite data, providing a record of estimated forest phenological variation from 1982-1993. The seasonal Normalized Difference Vegetation Index (NDVI) amplitude (a proxy for phenology) increased throughout much of the basin during El Nino periods when rainfall was anomalously low. Wetter La Nina episodes brought consistently smaller NDVI amplitudes. Using radiative transfer and terrestrial biogeochemical models driven by these satellite data, we estimate that canopy-energy absorption and net primary production of Amazon forests varied interannually by as much as 21% and 18%, respectively. These results provide large-scale observational evidence for interannual sensitivity to El Nino of plant phenology and carbon flux in Amazon forests.

  10. ULF wave observations in the topside ionosphere from the low-Earth orbit Swarm satellites

    NASA Astrophysics Data System (ADS)

    Balasis, Georgios; Daglis, Ioannis A.; Papadimitriou, Constantinos; Giannakis, Omiros

    2016-07-01

    The ongoing Swarm satellite mission provides an opportunity to a better knowledge of the near-Earth electromagnetic environment. Herein, we study the occurrence of ultra low frequency (ULF) wave events observed by the Swarm satellite mission for a period spanning twenty months after the constellation's final configuration. We present maps of the dependence of ULF wave power with magnetic latitude and magnetic local time (MLT) as well as geographic latitude and longitude from the three satellites at their different locations in the topside ionosphere. We derive daily and monthly variations of the Pc3 wave power (20-100 mHz) and show distributions for various wave properties of the detected events. Moreover, we include Swarm power maps of equatorial spread-F (ESF) signatures in the topside ionosphere revealing a global mirror fine structure along the magnetic equator for these instabilities. We also found an enhancement of ESF power in the region of South Atlantic Anomaly (SAA) in agreement with the recently discovered by Swarm enhancement of compressional Pc3 wave energy in SAA. By combining Swarm results with wave observations from magnetospheric missions and ground-based magnetometer arrays we offer a useful platform to monitor the wave evolution from the outer boundaries of Earth's magnetosphere through the topside ionosphere down to the surface.

  11. KAGLVis - On-line 3D Visualisation of Earth-observing-satellite Data

    NASA Astrophysics Data System (ADS)

    Szuba, Marek; Ameri, Parinaz; Grabowski, Udo; Maatouki, Ahmad; Meyer, Jörg

    2015-04-01

    One of the goals of the Large-Scale Data Management and Analysis project is to provide a high-performance framework facilitating management of data acquired by Earth-observing satellites such as Envisat. On the client-facing facet of this framework, we strive to provide visualisation and basic analysis tool which could be used by scientists with minimal to no knowledge of the underlying infrastructure. Our tool, KAGLVis, is a JavaScript client-server Web application which leverages modern Web technologies to provide three-dimensional visualisation of satellite observables on a wide range of client systems. It takes advantage of the WebGL API to employ locally available GPU power for 3D rendering; this approach has been demonstrated to perform well even on relatively weak hardware such as integrated graphics chipsets found in modern laptop computers and with some user-interface tuning could even be usable on embedded devices such as smartphones or tablets. Data is fetched from the database back-end using a ReST API and cached locally, both in memory and using HTML5 Web Storage, to minimise network use. Computations, calculation of cloud altitude from cloud-index measurements for instance, can depending on configuration be performed on either the client or the server side. Keywords: satellite data, Envisat, visualisation, 3D graphics, Web application, WebGL, MEAN stack.

  12. Data Dissemination System Status and Plan for Jaxa's Earth Observation Satellite Data

    NASA Astrophysics Data System (ADS)

    Fuda, M.; Miura, S.

    2012-12-01

    1. INTRODUCTION JAXA is Japan's national aerospace agency and responsible for research, technology development and the launch of satellites into orbit, and is involved in many more advanced missions, such as asteroid exploration and possible manned exploration of the Moon. Since 1978, JAXA started to disseminate earth observation data acquired by satellites to researchers and those data scene became more than two Million scenes in 2011. This paper focuses on the status and future plan for JAXA's Data Dissemination System for those data. 2. STATUS JAXA is Japan's national aerospace agency and responsible for research, technology development and the launch of satellites into orbit. In October 1978, JAXA opened the Earth Observation Center (EOC) and started to archive and disseminate earth observation data acquired by multiple satellites. 2.1. Target data Currently, the disseminated data includes "JAXA's satellite/sensor data" and "non-JAXA's satellite/sensor data", as shown in Table 2-1. In 2011, the total disseminated data scene became more than two Million scenes. 2.2. Data Dissemination Guideline The JAXA basic data dissemination guideline is a free for researchers and specific agencies. JAXA has two approaches for dissemination. One is that the data is distributed for specific agencies by Mission Operation Systems (MOS). Each project has its own MOS, for example, GCOM-W1 has a GCOM-W1 MOS. Another is that the data is disseminated for many researchers by Data Distribution Systems. Now JAXA has three Data Distribution systems, EOIS, AUIG and GCOM-W1DPSS. Table 2-1 : Disseminated earth observation data from JAXA's facility Satellite Sensor Processing Level ALOS AVNIR-2 Level 1 PRISM Level 1 PALSAR Level 1 TRMM PR Level 1, 2, 3 CMB Level 1, 2, 3 TMI Level 1, 2, 3 VIR Level 1, 2, 3 Aqua AMSR-E Level 1, 2, 3 ADEOS-II AMSR Level 1, 2, 3 GLI-1km Level 1, 2, 3 GLI-250m Level 1, 2, 3 JERS-1 OSW Level 0, 1, 2 OVN Level 0, 1, 2, 5 SAR Level 1, 2 ADEOS AVNIR Level 1 OCTS

  13. Some properties of trans-equatorial ion whistlers observed by Isis satellites during geomagnetic storms

    NASA Technical Reports Server (NTRS)

    Watanabe, S.; Ondoh, T.

    1986-01-01

    Several ion whistlers were observed by the polar orbiting satellites, Isis, during geomagnetic storms associated with large solar flares in 1982. It seems that the proton density ratio to the total ions deduced from the crossover frequency of the transequatorial ion whistlers observed at geomagnetic low latitudes during the main phase of the geomagnetic storm on July 14, 1982 was lower than the usual density ratio. An anomalous pattern seen on the time-compressed dynamic spectra of the ion whistlers on September 6, 1982 may suggest the existence of effects by the component He(3+) in a quite small amount.

  14. Cirrus cloud-temperature interactions over a tropical station, Gadanki from lidar and satellite observations

    SciTech Connect

    S, Motty G Satyanarayana, M. Krishnakumar, V. Dhaman, Reji k.

    2014-10-15

    The cirrus clouds play an important role in the radiation budget of the earth's atmospheric system and are important to characterize their vertical structure and optical properties. LIDAR measurements are obtained from the tropical station Gadanki (13.5{sup 0} N, 79.2{sup 0} E), India, and meteorological indicators derived from Radiosonde data. Most of the cirrus clouds are observed near to the tropopause, which substantiates the strength of the tropical convective processes. The height and temperature dependencies of cloud height, optical depth, and depolarization ratio were investigated. Cirrus observations made using CALIPSO satellite are compared with lidar data for systematic statistical study of cirrus climatology.

  15. Research in space physics at the University of Iowa. [astronomical observatories, spaceborne astronomy, satellite observation

    NASA Technical Reports Server (NTRS)

    Vanallen, J. A.

    1974-01-01

    Various research projects in space physics are summarized. Emphasis is placed on: (1) the study of energetic particles in outer space and their relationships to electric, magnetic, and electromagnetic fields associated with the earth, the sun, the moon, the planets, and interplanetary medium; (2) observational work on satellites of the earth and the moon, and planetary and interplanetary spacecraft; (3) phenomenological analysis and interpretation; (4) observational work by ground based radio-astronomical and optical techniques; and (5) theoretical problems in plasma physics. Specific fields of current investigations are summarized.

  16. Evaluation of sulfate aerosol optical depths over the North Atlantic and comparison with satellite observations

    SciTech Connect

    Berkowitz, C.M.; Ghan, S.J.; Benkovitz, C.M.; Wagener, R.; Nemesure, S.; Schwartz, S.E.

    1993-11-01

    It has been postulated that scattering of sunlight by aerosols can significantly reduce the amount of solar energy absorbed by the climate system. Aerosol measurement programs alone cannot provide all the information needed to evaluate the radiative forcing due to anthropogenic aerosols. Thus, comprehensive global-scale aerosol models, properly validated against surface-based and satellite measurements, are a fundamental tool for evaluating the impacts of aerosols on the planetary radiation balance. Analyzed meteorological fields from the European Centre for Medium-Range Weather Forecasts are used to drive a modified version of the PNL Global Chemistry Model, applied to the atmospheric sulfur cycle. The resulting sulfate fields are used to calculate aerosol optical depths, which in turn are compared to estimates of aerosol optical depth based on satellite observations.

  17. Coincident multispectral satellite observations of marine stratocumulus clouds near the Azores Islands

    SciTech Connect

    Miletta, J.; Katsaros, K.B.

    1994-12-31

    Marine stratocumulus clouds (MSC) have been the subject of much climate research because of their effect on the earth`s radiative energy budget. The radiative properties of MSC are determined primarily by their water content and spatial distribution. Satellite data provide an excellent opportunity to characterize these parameters. In this study, the authors use coincident observations from two sensors on the same Defense Meteorological Satellite Program (DMSP) platform: visible and infrared data are provided by the Operational Linescan System (OLS), and passive microwave data are provided by the Special Sensor Microwave Imager (SSMI). The OLS data facilitate the interpretation of the atmospheric parameters retrieved from the SSMI by putting them in a familiar context and allowing a subpixel analysis of the relatively large SSMI footprint. The objective is to explore the relationships between the SSMI-derived and the OLS-derived cloud parameters.

  18. Contrasting trends in light pollution across Europe based on satellite observed night time lights

    PubMed Central

    Bennie, Jonathan; Davies, Thomas W.; Duffy, James P.; Inger, Richard; Gaston, Kevin J.

    2014-01-01

    Since the 1970s nighttime satellite images of the Earth from space have provided a striking illustration of the extent of artificial light. Meanwhile, growing awareness of adverse impacts of artificial light at night on scientific astronomy, human health, ecological processes and aesthetic enjoyment of the night sky has led to recognition of light pollution as a significant global environmental issue. Links between economic activity, population growth and artificial light are well documented in rapidly developing regions. Applying a novel method to analysis of satellite images of European nighttime lights over 15 years, we show that while the continental trend is towards increasing brightness, some economically developed regions show more complex patterns with large areas decreasing in observed brightness over this period. This highlights that opportunities exist to constrain and even reduce the environmental impact of artificial light pollution while delivering cost and energy-saving benefits. PMID:24445659

  19. Contrasting trends in light pollution across Europe based on satellite observed night time lights

    NASA Astrophysics Data System (ADS)

    Bennie, Jonathan; Davies, Thomas W.; Duffy, James P.; Inger, Richard; Gaston, Kevin J.

    2014-01-01

    Since the 1970s nighttime satellite images of the Earth from space have provided a striking illustration of the extent of artificial light. Meanwhile, growing awareness of adverse impacts of artificial light at night on scientific astronomy, human health, ecological processes and aesthetic enjoyment of the night sky has led to recognition of light pollution as a significant global environmental issue. Links between economic activity, population growth and artificial light are well documented in rapidly developing regions. Applying a novel method to analysis of satellite images of European nighttime lights over 15 years, we show that while the continental trend is towards increasing brightness, some economically developed regions show more complex patterns with large areas decreasing in observed brightness over this period. This highlights that opportunities exist to constrain and even reduce the environmental impact of artificial light pollution while delivering cost and energy-saving benefits.

  20. Contrasting trends in light pollution across Europe based on satellite observed night time lights.

    PubMed

    Bennie, Jonathan; Davies, Thomas W; Duffy, James P; Inger, Richard; Gaston, Kevin J

    2014-01-21

    Since the 1970s nighttime satellite images of the Earth from space have provided a striking illustration of the extent of artificial light. Meanwhile, growing awareness of adverse impacts of artificial light at night on scientific astronomy, human health, ecological processes and aesthetic enjoyment of the night sky has led to recognition of light pollution as a significant global environmental issue. Links between economic activity, population growth and artificial light are well documented in rapidly developing regions. Applying a novel method to analysis of satellite images of European nighttime lights over 15 years, we show that while the continental trend is towards increasing brightness, some economically developed regions show more complex patterns with large areas decreasing in observed brightness over this period. This highlights that opportunities exist to constrain and even reduce the environmental impact of artificial light pollution while delivering cost and energy-saving benefits.

  1. Local cooling and warming effects of forests based on satellite observations.

    PubMed

    Li, Yan; Zhao, Maosheng; Motesharrei, Safa; Mu, Qiaozhen; Kalnay, Eugenia; Li, Shuangcheng

    2015-03-31

    The biophysical effects of forests on climate have been extensively studied with climate models. However, models cannot accurately reproduce local climate effects due to their coarse spatial resolution and uncertainties, and field observations are valuable but often insufficient due to their limited coverage. Here we present new evidence acquired from global satellite data to analyse the biophysical effects of forests on local climate. Results show that tropical forests have a strong cooling effect throughout the year; temperate forests show moderate cooling in summer and moderate warming in winter with net cooling annually; and boreal forests have strong warming in winter and moderate cooling in summer with net warming annually. The spatiotemporal cooling or warming effects are mainly driven by the two competing biophysical effects, evapotranspiration and albedo, which in turn are strongly influenced by rainfall and snow. Implications of our satellite-based study could be useful for informing local forestry policies.

  2. Wave observation in the marginal ice zone with the TerraSAR-X satellite

    NASA Astrophysics Data System (ADS)

    Gebhardt, Claus; Bidlot, Jean-Raymond; Gemmrich, Johannes; Lehner, Susanne; Pleskachevsky, Andrey; Rosenthal, Wolfgang

    2016-07-01

    This article investigates the penetration of ocean waves into the marginal ice zone (MIZ), observed by satellite, and likewise provides a basis for the future cross-validation of respective models. To this end, synthetic aperture radar images from the TerraSAR-X satellite (TS-X) and numerical simulations of the European Centre for Medium-Range Weather Forecasts (ECMWF) are used. The focus is an event of swell waves, developed during a storm passage in the Atlantic, penetrating deeply into the MIZ off the coast of Eastern Greenland in February 2013. The TS-X scene which is the basis for this investigation extends from the ice-free open ocean to solid ice. The variation of the peak wavelength is analysed and potential sources of variability are discussed. We find an increase in wavelength which is consistent with the spatial dispersion of deep water waves, even within the ice-covered region.

  3. Ozone Pollution, Transport and Variability: Examples from Satellite and In-Situ Observations

    NASA Technical Reports Server (NTRS)

    Thompson, Anne

    2003-01-01

    Regional and intercontinental transport of ozone has been observed from satellite, aircraft and sounding data. Over the past several years, we have developed new tropospheric ozone retrieval techniques from the TOMS (Total Ozone Mapping Spectrometer) satellite instrument that are of sufficient resolution to follow pollution episodes. The modified-residual technique uses Level 2 total ozone and was used to follow the 1997 fires in the wake of the El-Nino-related fires in southeast Asia and the Indonesian maritime continent. The TOMS-direct method ('TDOT' = TOMS Direct Ozone in the Troposphere) is a newer algorithm that uses TOMS radiances directly to extract tropospheric ozone. Ozonesonde data that have been taken in campaigns (e.g. TRACE-P) and more consistently in the SHADOZ (Southern Hemisphere Additional Ozonesondes) project, reveal layers of pollution traceable with trajectories. Examples will be shown of long-range transport and recirculation over Africa during SAFARI-2000.

  4. Local cooling and warming effects of forests based on satellite observations

    PubMed Central

    Li, Yan; Zhao, Maosheng; Motesharrei, Safa; Mu, Qiaozhen; Kalnay, Eugenia; Li, Shuangcheng

    2015-01-01

    The biophysical effects of forests on climate have been extensively studied with climate models. However, models cannot accurately reproduce local climate effects due to their coarse spatial resolution and uncertainties, and field observations are valuable but often insufficient due to their limited coverage. Here we present new evidence acquired from global satellite data to analyse the biophysical effects of forests on local climate. Results show that tropical forests have a strong cooling effect throughout the year; temperate forests show moderate cooling in summer and moderate warming in winter with net cooling annually; and boreal forests have strong warming in winter and moderate cooling in summer with net warming annually. The spatiotemporal cooling or warming effects are mainly driven by the two competing biophysical effects, evapotranspiration and albedo, which in turn are strongly influenced by rainfall and snow. Implications of our satellite-based study could be useful for informing local forestry policies. PMID:25824529

  5. Local cooling and warming effects of forests based on satellite observations.

    PubMed

    Li, Yan; Zhao, Maosheng; Motesharrei, Safa; Mu, Qiaozhen; Kalnay, Eugenia; Li, Shuangcheng

    2015-01-01

    The biophysical effects of forests on climate have been extensively studied with climate models. However, models cannot accurately reproduce local climate effects due to their coarse spatial resolution and uncertainties, and field observations are valuable but often insufficient due to their limited coverage. Here we present new evidence acquired from global satellite data to analyse the biophysical effects of forests on local climate. Results show that tropical forests have a strong cooling effect throughout the year; temperate forests show moderate cooling in summer and moderate warming in winter with net cooling annually; and boreal forests have strong warming in winter and moderate cooling in summer with net warming annually. The spatiotemporal cooling or warming effects are mainly driven by the two competing biophysical effects, evapotranspiration and albedo, which in turn are strongly influenced by rainfall and snow. Implications of our satellite-based study could be useful for informing local forestry policies. PMID:25824529

  6. Application of satellite data in observational and theoretical studies of the evolving structure of baroclinic waves

    NASA Technical Reports Server (NTRS)

    Saltzman, Barry

    1987-01-01

    A variety of observational and theoretical studies were performed which were designed to clarify the relationship between satellite measurements of cloud and radiation and the evolution of transient and stationary circulation in middle latitudes. Satellite outgoing longwave radiation data are used to: (1) estimate the generation of available potential energy due to infrared radiation, and (2) show the extent to which these data can provide the signature of high and low frequency weather phenomena including blocking. In a significant series of studies the nonlinear, energetical, and predictability properties of these blocking situations, and the ralationship of blocking to the planetary, scale longwave structure are described. These studies form the background for continuing efforts to describe and theoretically account for these low frequency planetary wave phenomena in terms of their bimodal properties.

  7. Evaluation of methods to derive green-up dates based on daily NDVI satellite observations

    NASA Astrophysics Data System (ADS)

    Doktor, Daniel

    2010-05-01

    Bridging the gap between satellite derived green-up dates and in situ phenological observations has been the purpose of many studies over the last decades. Despite substantial advancements in satellite technology and data quality checks there is as yet no universally accepted method for extracting phenological metrics based on satellite derived vegetation indices. Dependent on the respective method derived green-up dates can vary up to serveral weeks using identical data sets. Consequently, it is difficult to compare various studies and to accurately determine an increased vegetation length due to changing temperature patterns as observed by ground phenological networks. Here, I compared how the characteristic NDVI increase over temperate deciduous forests in Germany in spring relates to respective budburst events observed on the ground. MODIS Terra daily surface reflectances with a 250 m resolution (2000-2008) were gathered to compute daily NDVI values. As ground truth, observations of the extensive phenological network of the German Weather Service were used. About 1500 observations per year and species (Beech, Oak and Birch) were available evenly distributed all over Germany. Two filtering methods were tested to reduce the noisy raw data. The first method only keeps NDVI values which are classified as ‚ideal global quality' and applies on those a temporal moving window where values are removed which differ more than 20% of the mean. The second method uses an adaptation of the BISE (Best Index Slope Extraction) algorithm. Subsequently, three functions were fitted to the selected observations: a simple linear interpolation, a sigmoidal function and a double logistic sigmoidal function allowing to approximate two temporally separated green-up signals. The green-up date was then determined at halfway between minimum and maximum (linear interpolation) or at the inflexion point of the sigmoidal curve. A number of global threshold values (NDVI 0.4,0.5,0.6) and

  8. HST Observations of Saturnian Satellites during the 1995 Ring Plane Crossings

    NASA Astrophysics Data System (ADS)

    McGhee, Colleen A.; Nicholson, Philip D.; French, Richard G.; Hall, Katherine J.

    2001-08-01

    In May, August, and November 1995, Hubble Space Telescope (HST) observations during Saturn's ring-plane crossings allowed us to view saturnian satellites normally hidden to Earth-based observers in the glare of the rings. New measurements of Janus, Epimetheus, Prometheus, and Pandora have been combined to form revised orbital solutions using all three HST data sets. These measurements and orbit fits are presented, as well as similar fits for the brighter satellites Mimas, Tethys, Enceladus, Dione, and Rhea. Observations of the Lagrangian satellites Telesto, Calypso, and Helene are also reported. While most satellites were found to be close to their expected positions based on previous orbital solutions (Nicholson et al. 1992, Icarus100, 464-484; Jacobson 1996, Bull. Amer. Astron. Soc.28, 1185; and Harper and Taylor 1993, Astron. Astrophys. 268, 326-349). Prometheus lagged behind its predicted longitude by 18.85°±0.04°. A systematic drift in Pandora's longitude of -1.85° relative to the Voyager ephemeris was observed between May and November. The new data on the coorbital satellites Janus and Epimetheus have resulted in a revised mass for Janus, ˜6% smaller than the previous value (Jacobson 1995, Bull. Amer. Astron. Soc.27, 1202). Subtraction of light from the edge-on rings has led to additional detections of objects S/1995-S1 and S3 (Bosh and Rivkin 1995, Science272, 518-521) in the May data, and S/1995-S5, S6, S7 (Nicholson et al. 1995, Bull. Amer. Astron. Soc. 27, 1202) and S/1995-S9 (Roddier et al. 1996) in the August images. S1 is identified with Atlas but leads its predicted position by ˜25°. S3 has an orbit consistent with that of the narrow F ring, but S5, S6, S7, and S9 now appear to orbit ˜530-950 km interior to this ring. S7 and S9 may even be coorbital with Prometheus. An object in the May images, possibly corresponding to S7, is also found to lie very close to Prometheus' orbit (˜800 km interior to the F ring), but no convincing detections of

  9. Scheduling satellite imagery acquisition for sequential assimilation of water level observation into flood modelling

    NASA Astrophysics Data System (ADS)

    García-Pintado, Javier; Neal, Jeff C.; Mason, David C.; Dance, Sarah L.; Bates, Paul D.

    2013-04-01

    Satellite-based imagery has proved useful for obtaining information on water levels in flood events. Microwave frequencies are generally more useful for flood detection than visible-band sensors because of its all-weather day-night capability. Specifically, the future SWOT mission, with Ka-band interferometry, will be able to provide direct Water Level Observations (WLOs), and current and future Synthetic Aperture Radar (SAR) sensors can provide information of flood extent, which, when intersected with a Digital Elevation Model (DEM) of the floodplain, provides indirect WLOs. By either means, satellite-based WLOs can be assimilated into a hydrodynamic model to decrease forecast uncertainty and further to estimate river discharge into the flooded domain. Operational scenarios can even make a combined use of imagery from different uncoordinated missions to sequentially estimate river discharge. Thus, with an increasing number of operational satellites with WLO capability, information on the relationship between satellite first visit, revisit times, and forecast performance is required to optimise the operational scheduling of satellite imagery. By using an Ensemble Transform Kalman Filter (ETKF) and a synthetic analysis with the 2D hydrodynamic model LISFLOOD-FP based on a real flooding case affecting an urban area (summer 2007, Tewkesbury, Southwest UK), we evaluate the sensitivity of the forecast performance to visit parameters. As an example, we use different scenarios of revisit times and observational errors expected from the current COSMO-Skymed (CSK) constellation, with X-band SAR. We emulate a generic hydrologic-hydrodynamic modelling cascade by imposing a bias and spatiotemporal correlations to the inflow error ensemble into the hydrodynamic domain. First, in agreement with previous research, estimation and correction for this bias leads to a clear improvement in keeping the forecast on track. Second, imagery obtained early in the flood is shown to have a

  10. Mapping man-made CO2 emissions using satellite-observed nighttime lights

    NASA Astrophysics Data System (ADS)

    Oda, T.; Maksyutov, S. S.; Andres, R. J.; Elvidge, C.; Baugh, K.; Hsu, F. C.; Roman, M. O.

    2015-12-01

    The Open-Data Inventory for Anthropogenic Carbon dioxide (ODIAC) is a global high spatial resolution (1x1km) emission dataset for CO2 emissions from fossil fuel combustion. The original version of ODIAC was developed at the Japanese Greenhouse Gas Observing Satellite (GOSAT) project to prescribe their inverse model. ODIAC first introduced the combined use of satellite-observed nighttime light data and individual power plant emission/geolocation information to estimate the spatial extent of fossil fuel CO2. The ODIAC emission data has been widely used by the international carbon cycle research community and appeared in a number of publications in the literature. Since its original publication in 2011, we have made numerous modifications to the ODIAC emission model and the emission data have been updated on annual basis. We are switching from BP statistical data based emission estimates to estimates made by Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory. In recent versions of ODIAC data, the emission seasonality has been adopted from the CDIAC monthly emission dataset. The emissions from international bunkers, which are not included in the CDIAC gridded emission data, are estimated using the UN Energy Database and included with the spatial distributions. In the next version of ODIAC emission model, we will explore the use of satellite data collected by the NASA's Suomi National Polar-orbiting Partnership (NPP) satellite. We will estimate emission spatial distributions using global 500x500m nighttime lights data created from VIIRS data. We will also utilize a combustion detection algorithm Nightfire developed at NOAA National Geophysical Data Center to map gas flaring emissions. We also plan to expand our two emission sector emission distributing approach (power plant emission and non-point source emissions) by introducing a transportation emission sector which should improve emission distributions in urban and rural areas.

  11. Large-scale and Convective-scale Updraft Profiles from Satellite Observations

    NASA Astrophysics Data System (ADS)

    Masunaga, H.; Luo, Z. J.

    2015-12-01

    Among the crucial problems involved in the tropical energy budget are the thermodynamic effects of an ensemble of convective clouds on their environment and the large-scale influence imposed back on the convective-scale dynamics. Efforts to seek observational evidence for this problem, however, are challenged by limitations in the capability of measuring vertical motion across different horizontal scales. We have recently been exploring new analysis strategies in hopes to make this seemingly impossible possible, exploiting a suite of satellite instruments including the CloudSat and TRMM radars and Aqua AIRS. Since a complete vertical structure of in-cloud vertical velocity, wc, is unable to be reconstructed from satellite measurements alone, a single-column plume model is run with the environmental soundings from AIRS to obtain a set of synthetic wc profiles under a range of entrainment rates. The solutions are then narrowed down in a Bayesian manner so as to match the cloud-top vertical velocity and buoyancy estimates from A-Train infrared and radar measurements. The vertical profile of large-scale mean vertical motion, ω, is also evaluated from satellite observations in its own approach: ω as a function of pressure is determined so that it satisfies the horizontal divergence terms in the tropospheric water and thermal budget equations in which the remaining terms are constrained by satellite measurements. In this talk, the methodology is briefly outlined and the results are presented and discussed in light of outstanding issues in tropical dynamics. The wc and ω estimates above, although subject to intrinsic uncertainties yet to be verified, do not involve any closure assumption as required for cumulus parameterizations and would offer a useful test bed for climate models and reanalysis data as well as a unique opportunity to study the mechanism of tropical convection.

  12. Application of a Topological Metric for Assessing Numerical Ocean Models with Satellite Observations

    NASA Astrophysics Data System (ADS)

    Morey, S. L.; Dukhovskoy, D. S.; Hiester, H. R.; Garcia-Pineda, O. G.; MacDonald, I. R.

    2015-12-01

    Satellite-based sensors provide a vast amount of observational data over the world ocean. Active microwave radars measure changes in sea surface height and backscattering from surface waves. Data from passive radiometers sensing emissions in multiple spectral bands can directly measure surface temperature, be combined with other data sources to estimate salinity, or processed to derive estimates of optically significant quantities, such as concentrations of biochemical properties. Estimates of the hydrographic variables can be readily used for assimilation or assessment of hydrodynamic ocean models. Optical data, however, have been underutilized in ocean circulation modeling. Qualitative assessments of oceanic fronts and other features commonly associated with changes in optically significant quantities are often made through visual comparison. This project applies a topological approach, borrowed from the field of computer image recognition, to quantitatively evaluate ocean model simulations of features that are related to quantities inferred from satellite imagery. The Modified Hausdorff Distance (MHD) provides a measure of the similarity of two shapes. Examples of applications of the MHD to assess ocean circulation models are presented. The first application assesses several models' representation of the freshwater plume structure from the Mississippi River, which is associated with a significant expression of color, using a satellite-derived ocean color index. Even though the variables being compared (salinity and ocean color index) differ, the MHD allows contours of the fields to be compared topologically. The second application assesses simulations of surface oil transport driven by winds and ocean model currents using surface oil maps derived from synthetic aperture radar backscatter data. In this case, maps of time composited oil coverage are compared between the simulations and satellite observations.

  13. Earth Observation Convoy: Synergetic Observations with Satellites Flying in Formation with European Operational Missions - Possibilities for New Science

    NASA Astrophysics Data System (ADS)

    Regan, A.; Silvestrin, P.; Fernandez, D.; Leveque, N.; Eves, S.

    2012-04-01

    Over the next few years a number of new long-term operational Earth Observation (EO) satellites will be launched by Europe. These missions include the GMES (Global Monitoring for Environment and Security) Sentinel spacecraft and the EUMETSAT operated Metop satellite series. These missions will provide global, continuous and long-term European capability for systematic observation of a panoply of Earth system parameters. If additional cost-effective missions could be flown together with these operational missions then the possibilities for meeting new Earth science and application objectives could be far-reaching e.g. fulfilling observational gaps, multipoint measurement of Earth system phenomena, etc. Therefore, the European Space Agency (ESA) is funding three exploratory activities (known as the EO-Convoy studies). The aim of these studies is two fold: Firstly, to identify scientific and operational objectives and needs which would benefit from additional in-orbit support. Secondly, to identify and develop a number of cost-effective mission concepts that would meet these identified objectives and needs. Each EO Convoy study is dedicated to a specific theme: • Study 1: Ocean and Ice • Study 2: Land • Study 3: Atmosphere Each study is based on a comprehensive user needs analysis derived from Earth science analysis, applications and identification of novel data products. Based on this analysis a number of preliminary mission concepts are derived together with possible formation and constellation options. Up to three mission concepts per theme are then selected for detailed analysis including a roadmap for development. For the Ocean and Ice EO Convoy study the scientific analysis identified a number of areas where support measurements from additional satellites would prove valuable e.g. ocean topography and ocean currents, ocean colour, sea surface salinity, sea-ice drift and thickness, sea-ice melt on-set and duration, snow accumulation on ice sheets, freeze

  14. Assessment of satellite-based aerosol optical depth using continuous lidar observation

    NASA Astrophysics Data System (ADS)

    Lin, C. Q.; Li, C. C.; Lau, A. K. H.; Yuan, Z. B.; Lu, X. C.; Tse, K. T.; Fung, J. C. H.; Li, Y.; Yao, T.; Su, L.; Li, Z. Y.; Zhang, Y. Q.

    2016-09-01

    Due to a reliance on solar radiation, the aerosol optical depth (AOD) is observed only during the day by passive satellite-based instruments such as the MODerate resolution Imaging Spectroradiometer (MODIS). Research on urban air quality, atmospheric turbidity, and evolution of aerosols in the atmospheric boundary layer, however, requires 24-h measurement of aerosols. A lidar system is capable of detecting the vertical distribution of the aerosol extinction coefficient and calculating the AOD throughout the day, but routinely lidar observation is still quite limited and the results from MODIS and lidar sometimes are contradictory in China. In this study, long-term lidar observations from 2005 to 2009 over Hong Kong were analyzed with a focus on identification of the reasons for different seasonal variation in the AOD data obtained from MODIS and lidar. The lidar-retrieved AOD shows the lowest average level, but has the most significant diurnal variation during the summer. When considering only a 5-h period between 10:00 a.m. and 3:00 p.m. local time to match satellite passages, the average of the lidar-retrieved AOD doubles during the summer and exceeds that during the winter. This finding is consistent with the MODIS observation of a higher AOD during the summer and a lower AOD during the winter. The increase in the aerosol extinction coefficient in the upper level of the mixing layer makes the greatest contribution to the increase in the AOD at midday during the summer. These assessments suggest that large over-estimation may occur when long-term averages of AOD are estimated from passive satellite observations.

  15. Improving the Transition of Earth Satellite Observations from Research to Operations

    NASA Technical Reports Server (NTRS)

    Goodman, Steven J.; Lapenta, William M.; Jedlovec, Gary J.

    2004-01-01

    There are significant gaps between the observations, models, and decision support tools that make use of new data. These challenges include: 1) Decreasing the time to incorporate new satellite data into operational forecast assimilation systems, 2) Blending in-situ and satellite observing systems to produce the most accurate and comprehensive data products and assessments, 3) Accelerating the transition from research to applications through national test beds, field campaigns, and pilot demonstrations, and 4) Developing the partnerships and organizational structures to effectively transition new technology into operations. At the Short-term Prediction Research and Transition (SPORT) Center in Huntsville, Alabama, a NASA-NOAA-University collaboration has been developed to accelerate the infusion of NASA Earth science observations, data assimilation and modeling research into NWS forecast operations and decision-making. The SPoRT Center research focus is to improve forecasts through new observation capability and the regional prediction objectives of the US Weather Research Program dealing with 0-1 day forecast issues such as convective initiation and 24-hr quantitative precipitation forecasting. The near real-time availability of high-resolution experimental products of the atmosphere, land, and ocean from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Advanced Infrared Spectroradiometer (AIRS), and lightning mapping systems provide an opportunity for science and algorithm risk reduction, and for application assessment prior to planned observations from the next generation of operational low Earth orbiting and geostationary Earth orbiting satellites. This paper describes the process for the transition of experimental products into forecast operations, current products undergoing assessment by forecasters, and plans for the future. The SPoRT Web page is at (http://www.ghcc.msfc.nasa.gov/sport).

  16. Multi-satellite observations of energy transport during an intense geomagnetic storm

    NASA Astrophysics Data System (ADS)

    Yang, Jian; Ma, Yuduan; Duan, Aiying; Dunlop, M. W.

    2016-05-01

    Energy transport during a geomagnetic substorm is a very important process for solar wind-magnetosphere energy coupling and the energy cycle in the magnetotail. In this paper, we use magnetotail data from the five THEMIS probes and two Cluster satellites on the dayside to investigate the energy transport of one intense storm during the period from 08 March to 11 March 2008 at large spatial-temporal scales. Simultaneous observations of the five THEMIS probes indicate that there is a stronger and earlier duskward energy flux density in the near-Earth magnetotail than that in the mid-tail in the initial phase. Low energy particles inject earthward from the dusk flank. Stronger and more variable earthward energy flux density is observed in the mid-tail compared to that near Earth in the main phase; mainly caused by high-speed flow. Tailward energy flux was observed in the near-Earth and mid-tail regions during the recovery phase. Dayside data observed by two Cluster satellites show that the duskward energy flux may be related to stable solar wind input. Tailward energy flux on the dayside should experience some energy conversion process in the magnetotail before it can provide the earthward energy flux in the magnetotail for this intense storm. The strongest energy transport observed by the nightside probes occurs in the main phase. However, the strongest energy measured by the dayside satellites is in the recovery phase without intense activities, two hours later. Different features of the energy transport in the three phases of the storm may be closely related to the different physical processes such as the energy entry, westward drift, particle injection or other potential mechanisms.

  17. How do Biomass Burning Carbon Monixide Emissions from South America influence Satellite Observed Columns over Africa?

    NASA Astrophysics Data System (ADS)

    Krol, M. C.; van Leeuwen, T. T.; Aouizerats, B.; van der Werf, G.

    2015-12-01

    Large amounts of Carbon Monoxide (CO) are emitted during biomass burning events. These emissions severely perturb the atmospheric composition. For this reason, satellite observations of CO can help to constrain emissions from biomass burning. Other sources of CO, such as the production of CO from naturally emitted non-methane hydrocarbons, may interfere with CO from biomass burning and inverse modeling efforts to estimate biomass burning emissions have to account for these CO sources. The atmospheric lifetime of CO varies from weeks to months, depending on the availability of atmospheric OH for atmospheric oxidation of CO to carbon dioxide. This means that CO can be transported over relatively long distances. It also implies that satellite-observed CO does not necessarily originate from the underlying continent, but may be caused by distant emissions transported to the observation location. In this presentation we focus on biomass burning emissions from South America and Southern Africa during 2010. This year was particularly dry over South America with a large positive anomaly in biomass burning in the 2010 burning season (July-October). We will adress the question how CO plumes from South America biomass burning influence satellite observations from the Infrared Atmospheric Sounding Interferometer (IASI) instrument over Southern Africa. For this we employ the TM5 atmospheric chemistry model, with 1x1 degree zoom resolutions over Africa and South America. Also, we use the TM5-4DVAR code to estimate CO biomass burning emissions using IASI CO observations. The accompanying image shows IASI CO oberservations over Africa on August 27, 2010, compared to the columns simulated with TM5. Clear signs of intercontinental transport from South America are visible over the Southermost region.

  18. Combining satellite observations to develop a global soil moisture product for near-real-time applications

    NASA Astrophysics Data System (ADS)

    Enenkel, Markus; Reimer, Christoph; Dorigo, Wouter; Wagner, Wolfgang; Pfeil, Isabella; Parinussa, Robert; De Jeu, Richard

    2016-10-01

    The soil moisture dataset that is generated via the Climate Change Initiative (CCI) of the European Space Agency (ESA) (ESA CCI SM) is a popular research product. It is composed of observations from 10 different satellites and aims to exploit the individual strengths of active (radar) and passive (radiometer) sensors, thereby providing surface soil moisture estimates at a spatial resolution of 0.25°. However, the annual updating cycle limits the use of the ESA CCI SM dataset for operational applications. Therefore, this study proposes an adaptation of the ESA CCI product for daily global updates via satellite-derived near-real-time (NRT) soil moisture observations. In order to extend the ESA CCI SM dataset from 1978 to present we use NRT observations from the Advanced Scatterometer on-board the two MetOp satellites and the Advanced Microwave Scanning Radiometer 2 on-board GCOM-W. Since these NRT observations do not incorporate the latest algorithmic updates, parameter databases and intercalibration efforts, by nature they offer a lower quality than reprocessed offline datasets. In addition to adaptations of the ESA CCI SM processing chain for NRT datasets, the quality of the NRT datasets is a main source of uncertainty. Our findings indicate that, despite issues in arid regions, the new CCI NRT dataset shows a good correlation with ESA CCI SM. The average global correlation coefficient between CCI NRT and ESA CCI SM (Pearson's R) is 0.80. An initial validation with 40 in situ observations in France, Spain, Senegal and Kenya yields an average R of 0.58 and 0.49 for ESA CCI SM and CCI NRT, respectively. In summary, the CCI NRT product is nearly as accurate as the existing ESA CCI SM product and, therefore, of significant value for operational applications such as drought and flood forecasting, agricultural index insurance or weather forecasting.

  19. Comparison of Arabian plate motion using satellite laser ranging and GPS observations

    NASA Astrophysics Data System (ADS)

    Alothman, A. O.; Fernandes, R. M.; Schillak, S. R.

    2013-12-01

    Two different space based observations have been used to estimate the velocity of the Arabian plate motion. The first set of observations is using the Saudi Arabia Laser Ranging Observatory (SALRO - 7832), which is situated in the middle of Arabian tectonic plate. Satellite Laser Ranging (SLR) observations of about 20 global SLR stations to LAGEOS-1 and LAGEOS-2 satellites collected for 14 years (1996-2009) have been used to determine Riyadh SLR station positions. The NASA Godard's GEODYN-II orbital software has been used to perform orbit determination of these two satellites. The velocities of SALRO were computed in reference to the ITRF2008 terrestrial reference frame. The second set of observations consists of Global Positioning System (GPS) observations of 15 GPS stations acquired in campaign and continuous mode for the period 2003 to 2009 (having at least 3 years' data span). Multi-year processing of stations having at least 3 years' time span and excluding stations within the deformation zone of Red Sea Ridge, such that they are distributed evenly within the rigid (interior) part of the Arabian plate. The Bernese 5.0/ADNEQ2 and GIPSY/OASIS 6.1 software packages were used to compute the daily solutions of coordinate time series applying the Precise Point Positioning (PPP) strategy. The velocities were estimated with respect to ITRF2008 and four estimates of the angular velocities for the Arabian plate have been computed using different datasets: independent Bernese and GIPSY solutions, combination of the GPS solutions only, and including the SLR solution. We present direct comparison between all different solutions showing that the Arabian tectonic plate motion determined from Riyadh SLR data and GPS data are in a good agreement with recent estimates, in particular with the global geodetic model GEODVEL and the geophysical MORVEL model.

  20. The PHEMU97 catalogue of observations of the mutual phenomena of the Galilean satellites of Jupiter

    NASA Astrophysics Data System (ADS)

    Arlot, J.-E.; Thuillot, W.; Ruatti, C.; Akasawa, H.; Baroni, S.; Beisker, W.; Berthier, J.; Blanco, C.; Boonstra, J.; Bourgeois, J.; Bulder, H.; Casas, R.; Castano, J. G.; Colas, F.; Collins, D.; Cuypers, J.; Czech, W.; D'Ambrosio, V.; Denzau, H.; Descamps, P.; Dimitrescu, A.; Dinakarian, N.; Dourneau, G.; Emelyanov, N.; Enriquez, J. M.; Fernandez, J. M.; Fernandez-Barba, D.; Flatres, T.; Foglia, S.; Goncalves, M.; Guhl, K.; Helmer, G.; Hirose, T.; Irsmambetova, T. R.; Krobusek, B. A.; Lecacheux, J.; Le Campion, J.-F.; Lou, M.; Mallama, A.; Marchis, F.; Navarro, M. A. S.; Nelson, P.; Okura, N.; Park, J.; Pauwels, T.; Pluchino, S.; Priban, V.; Rapaport, M.; Sacré, J.-J.; Salvaggio, F.; Sanchez, M. A.; Sanchez-Bajo, F.; Stefanescu, G.; Tanga, P.; Tejfel, V. G.; Trisan, J. L.; Trunkovsky, E. M.; van Gestel, J.; Vandenbulcke, G.; Vasundhara, R.; Vass, G.; Vingerhoets, P.; Vu, D. T.; Wilds, R. T.

    2006-05-01

    In 1997 the Sun and the Earth passed through the equatorial plane of Jupiter and therefore through the orbital planes of its main satellites. During this period, mutual eclipses and occultations occurred and were observed. We investigate the precision of the catalogue to produce improved data for the development of dynamical models. Light curves of mutual eclipses and occultations were recorded by the observers of the international campaign PHEMU97 organized by the Institut de Mécanique Céleste, Paris, France. We made 275 observations of 148 mutual events from 42 sites. For each observation, information is given about the telescope, the receiver, the site and the observational conditions. This paper gathers together the data and gives a first estimate of the precision. The catalogue of these rare events represents a collection of improved accurate astrometric data useful for the development of dynamical models.

  1. EMIC waves observed by the low-altitude satellite DEMETER during the November 2004 magnetic storm

    NASA Astrophysics Data System (ADS)

    Píša, D.; Parrot, M.; Santolík, O.; Menietti, J. D.

    2015-07-01

    This paper presents an analysis of ULF (0-20 Hz) waves observed by the low-altitude satellite Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) during the magnetic storm of November 2004. Since these ULF waves are measured by both electric and magnetic antennas, they may be identified as electromagnetic ion cyclotron (EMIC) waves. While EMIC waves have been previously observed in the low-altitude ionosphere, this is the first time that they are observed for such extensive time periods and at such high frequencies. A common feature of these emissions is that their observation region in the low-altitude ionosphere extends continuously from the high-latitude southern trough in one side up to the high-latitude northern trough. The analysis of wave propagation points to the possible source region placed in the inner magnetosphere (L ˜ 2-3). Observed wave frequencies indicate that waves must be generated much farther from the Earth compared to the satellite orbit. Exceptionally high frequencies of about 10 Hz can be explained by the source region placed in the deep inner magnetosphere at L ˜ 2.5. We hypothesize that these waves are generated below the local helium gyrofrequency and propagate over a large range of wave normal angles to reach low altitudes at L ˜ 1.11. In order to investigate this scenario, a future study based on ray tracing simulations will be necessary.

  2. Study of sub-auroral radio emissions observed by ICE experiment onboard DEMETER satellite

    NASA Astrophysics Data System (ADS)

    Boudjada, M. Y.; Galopeau, P. H. M.; Mogilevski, M. M.; Sawas, S.; Blecki, J.; Berthelier, J. J.; Voller, W.

    2012-04-01

    We report on the terrestrial kilometric and hectometric radio emissions recorded by the DEMETER/ICE (Instrument Champ Electrique) experiment. This instrument measures the electric field components of electromagnetic and electrostatic waves in the frequency range from DC to 3.25 MHz. Despite the limited satellite invariant latitude (data acquisition below about 65°), specific events have been observed, close to the sub-auroral region, in the frequency range from 100 kHz to about 1 MHz. This range covers the well-known auroral kilometric radiation (AKR), the terrestrial kilometric continuum, and the sub-auroral terrestrial emission at higher frequency up to 3 MHz. The high spectral capability of the experiment leads us to distinguish between the bursty and the continuum emissions. Selected events have been found to principally occur in the late evening and early morning sectors of the magnetosphere (22 MLT - 02 MLT) but others have been observed on the dayside. Our first results are compared to previous radio observations performed on board INTERBALL-1 (Kuril'chik et al, Cosmic Research, 43, 2005) and GEOTAIL (Hashimoto et al., JGR, 104, 1999) satellites. We also discuss the common and different features of the Earth and Jovian radio emissions. We emphasis on the observational parameters: the occurrence probability, the emission beam and the spectral emission types. We show that the physical interpretation of the auroral phenomena needs a good knowledge of the geometric configuration of the source and observer and the reception system (antenna beam and receivers).

  3. Broadband VHF observations for lightning impulses from a small satellite SOHLA-1 (Maido 1)

    NASA Astrophysics Data System (ADS)

    Morimoto, T.; Kikuchi, H.; Ushio, T.; Kawasaki, Z.; Hidekazu, H.; Aoki, T.

    2009-12-01

    analog-to-digital converter (ADC) to record broadband VHF pulses in orbit. The waveforms of 100 EM pulses in VHF band emitted from a lightning flash are obtained. Three pairs of BMW with accurate synchronized 3-channel-ADC are needed to realize DITF. From the successful satellite observation like TRMM/LIS, the effectiveness and impact of satellite observations for lightning are obvious. The combination of optical and VHF lightning observations are complimentary each other. ISS/JEM is a candidate platform to realize the simplest DITF and synchronous observations with optical sensors. SOHLA-1 was launched by a HII-A rocket at January 23, 2009 and named Maido-1. Then BMW has worked well and recorded VHF EM waveforms. The development of Maido-1 and its observations results will be presented.

  4. Model Evaluation with Multi-wavelength Satellite Observations Using a Neural Network

    NASA Astrophysics Data System (ADS)

    Kolassa, Jana; Jimenez, Carlos; Aires, Filipe

    2013-04-01

    A methodology has been developed to evaluate fields of modelled parameters against a set of satellite observations. The method employs a Neural Network (NN) to construct a statistical model capturing the relationship between the satellite observations and the parameter from a land surface model, in this case the Soil Moisture (SM). This statistical model is then used to estimate the parameter of interest from the set of satellite observations. These estimates are compared to the modelled parameter in order to detect local deviations indicating a possible problem in the model or in the satellite observations. Several synthetic tests, during which an artificial error was added to the"true" soil moisture fields, showed that the methodology is able to correct the errors (Jimenez et al., submitted, 2012). This evaluation technique is very general and can be applied to any modelled parameter for which sensitive satellite observations are available. The use of NNs simplifies the evaluation of the model against satellite observations and is particularly well-suited to utilize the synergy from the observations at different wavelengths (Aires et al., 2005, 2012). In this study the proposed methodology has been applied to evaluate SM fields from a number of land surface models against a synergy of satellite observations from passive and active microwave, infrared and visible sensors. In an inter-comparison of the performance of several land surface models (ORCHIDEE (de Rosnay et al., 2002), HTESSEL (Balsamo et al., 2009), JULES (Best et al., 2011) ) it was found that the soil moisture fields from JULES, HTESSEL and ORCHIDEE are very consistent with the observations, but ORCHIDEE soil moisture shows larger local deviations close to some river basins (Kolassa et al., in press, 2012; Jimenez et al., submitted, 2012). Differences between all models and the observations could also be observed in the Eastern US and over mountainous regions, however, the errors here are more likely

  5. Improved Specification of Transboundary Air Pollution over the Gulf of Mexico Using Satellite Observations

    NASA Astrophysics Data System (ADS)

    Pour Biazar, A.; Khan, M. N.; Park, Y. H.; McNider, R. T.; Cameron, B.

    2010-12-01

    The assessment of potential environmental impact of oil and gas operations in the Gulf of Mexico (GoM) and in particular the onshore air quality impact of such operations is important to State and Federal regulatory agencies. In adapting sound policies for control strategies, it is crucial to assess the impact of local pollution versus transboundary air pollution, and in a region such as GoM with scarce monitoring capability over open waters such distinctions represents a challenge. Furthermore, GoM region can be impacted by the recirculation of pollution in the southeastern United States. The current study examines the efficacy of utilizing the newly available satellite observations of aerosols and trace gases in air quality impacts assessment for addressing these issues. In particular, ozone profiles from the Tropospheric Emission Spectrometer (TES) and Ozone Monitoring Instrument (OMI) onboard Aura and aerosol products from Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra and Aqua satellites were utilized in a modeling study during August 2006. The satellite observations were used in the specification of the background and lateral boundary and also once daily for the re-adjustment of the concentration fields. The results were then evaluated against ozonesonde and surface observations. The utilization of OMI ozone profiles significantly improved model performance in the free troposphere and the use of MODIS aerosol products substantially enhanced model prediction of aerosols in the boundary layer. Neither OMI nor TES provide adequate information in the boundary layer with respect to O3 and as a result they can only marginally impact ozone predictions in the boundary layer. The utilization of the satellite data for lateral boundary condition (BC) was helpful in the realization of transboundary transport of pollution. The hypothesis that the recirculation of pollution from Northeast Corridor can play a role over the Gulf of Mexico was tested and

  6. Committee on Earth Observation Satellites (CEOS) perspectives about the GEO Supersite initiative

    NASA Astrophysics Data System (ADS)

    Lengert, Wolfgang; Zoffoli, Simona; Giguere, Christine; Hoffmann, Joern; Lindsay, Francis; Seguin, Guy

    2014-05-01

    This presentation is outlining the effort of the Committee on Earth Observation Satellites (CEOS) using its global collaboration structure to support implementing the GEO priority action DI-01 Informing Risk Management and Disaster Reduction addressing the component: C2 Geohazards Monitoring, Alert, and Risk Assessment. A CEOS Supersites Coordination Team (SCT) has been established in order to make best use of the CEOS global satellite resources. For this, the CEOS SCT has taken a holistic view on the science data needs and availability of resources, considering the constraints and exploitation potentials of synergies. It is interfacing with the Supersites Science Advisory Group and the Principle Investigators to analyze how the satellite data associated with seismic and Global Navigation Satellite System (GNSS) data can support national authorities and policy makers in risk assessment and the development of mitigation strategies. CEOS SCT aims to support the establishment of a fully integrated approach to geohazards monitoring, based on collaboration among existing networks and international initiatives, using new instrumentation such as in-situ sensors, and aggregating space (radar, optical imagery) and ground-based (subsurface) observations. The three Supersites projects which are funded under the EC FP7 action, namely (i) FUTUREVOLC: A European volcanological supersite in Iceland: a monitoring system and network for the future Geohazards Monitoring, Alert, and Risk Assessment, (ii) MARsite: New Directions in Seismic Hazard assessment through Focused Earth Observation in the Marmara Supersite, (iii) MED-SUV: MEDiterranean Volcanoes and related seismic risks, have been examined as a vehicle to fulfill these ambitious objectives. FUTUREVOLC has already been granted CEOS support. This presentation will outline CEOS agreed process and criteria applied by the Supersites Coordination Team (SCT), for selecting these Supersites in the context of the GSNL initiative, as

  7. Application of Airborne Sea Ice Observations Towards Improving Satellite-based Products

    NASA Astrophysics Data System (ADS)

    Tschudi, M. A.; Baldwin, D.; Liu, Y.; Dworak, R.; Key, J.

    2015-12-01

    Recent airborne and satellite observations suggest large decreases in Arctic sea ice thickness in recent years, but uncertainty remains in terms of overall loss of ice mass versus redistribution of mass within the Arctic Basin. In general though, the combination of airborne and satellite observations tend to agree that some thinning of the ice cover has occurred. In addition to changes in ice thickness and mass, other related changes in properties are likely if the ice pack is undergoing fundamental changes such as a shift to a largely seasonal sea-ice cover. Therefore, it is imperative to utilize airborne and surface-based observations to evaluate satellite-based sea ice products and to improve algorithms that estimate sea ice properties. Sea ice surface properties derived from NASA's Operation IceBridge (OIB) airborne measurements are currently being used to evaluate and update Suomi-NPP VIIRS sea ice products. Estimates of ice thickness derived from the OIB observations may be used to establish a relationship between sea ice thickness and the age of the ice. Drifting buoys serve to improve errors in tracking the movement of ice parcels through Arctic waters. Future airborne measurements of spectral reflectance during the melt season will improve algorithms that estimate melt pond fraction. We present examples of airborne validation of VIIRS sea ice products, relationships between sea ice thickness estimated from OIB measurements and sea ice age, and demonstrate the need for future airborne high-resolution estimates of surface reflectance, particularly in melt ponds. OIB thickness estimates over one sea ice age cell (12.5 km box) are shown in the attached figure.

  8. Density and crosswind from GOCE - comparisons with other satellite data, ground-based observations and models

    NASA Astrophysics Data System (ADS)

    Doornbos, E.; Bruinsma, S.; Conde, M.; Forbes, J. M.

    2013-12-01

    Observations made by the European Space Agency (ESA) Gravity field and Ocean Circulation Explorer (GOCE) satellite have enabled the production of a spin-off product of high resolution and high accuracy data on thermosphere density, derived from aerodynamic analysis of acceleration measurements. In this regard, the mission follows in the footsteps of the earlier accelerometer-carrying gravity missions CHAMP and GRACE. The extremely high accuracy and redundancy of the six accelerometers carried by GOCE in its gravity gradiometer instrument has provided new insights on the performance and calibration of these instruments. Housekeeping data on the activation of the GOCE drag free control thruster, made available by ESA has made the production of the thermosphere data possible. The long duration low altitude of GOCE, enabled by its drag free control system, has ensured the presence of very large aerodynamic accelerations throughout its lifetime. This has been beneficial for the accurate derivation of data on the wind speed encountered by the satellite. We have compared the GOCE density observations with data from CHAMP and GRACE. The crosswind data has been compared with CHAMP observations, as well as ground-based observations, made using Scanning Doppler Imagers in Alaska. Models of the thermosphere can provide a bigger, global picture, required as a background in the interpretation of the local space- and ground-based measurements. The comparison of these different sources of information on thermosphere density and wind, each with their own strengths and weaknesses, can provide scientific insight, as well as inputs for further refinement of the processing algorithms and models that are part of the various techniques. Density and crosswind data derived from GOCE (dusk-dawn) and CHAMP (midnight-noon) satellite accelerometer data, superimposed over HWM07 modelled horizontal wind vectors.

  9. Satellite irrigation management support with the terrestrial observation and prediction system: A framework for integration of satellite & surface observations to support improvements in agricultural water resource management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In California and other regions vulnerable to water shortages, satellite-derived estimates of key hydrologic parameters can support agricultural producers and water managers in maximizing the benefits of available water supplies. The Satellite Irrigation Management Support (SIMS) project combines N...

  10. Observations in the thermal IR and visible of a retired satellite in the graveyard orbit, and comparisons to active satellites in GEO

    NASA Astrophysics Data System (ADS)

    Skinner, Mark A.; Russell, Ray W.; Kelecy, Tom; Gregory, Steve; Rudy, Richard J.; Kim, Daryl L.; Crawford, Kirk

    2014-12-01

    There exists a population of defunct satellites in the geo-stationary arc that potentially pose a hazard to current and future operational satellites. These drifting, non-station-kept objects have a variety of ages and sizes, and many are trapped in libration orbits around the Earth's two gravitational potential wells (the non-spherical nature of the Earth gives rise to two geo-potential wells or "stable points" that affect objects in geostationary and geosynchronous orbits), whereas others were boosted to higher altitudes into so-called "graveyard" orbits. We have observed several of the approximately 49 objects in libration orbits about the Western stable point (R. Choc, T. Flohrer, and B. Bastida, "Classification of Geosynchronous Objects," Issue 13, ESA/ESOC, February 2011), as well as objects in graveyard orbits. We have carried out an observational campaign utilizing The Aerospace Corporation's 3-13 μm Broadband Array Spectrograph System (BASS), as well as with several optical sensors to collect data on a representative sample of these objects at a variety of solar phase angles. Here we report on recent BASS observations of a retired satellite in the "graveyard" orbit, and compare them with data we had collected over six years ago, while the satellite was still active. Data are also presented on similar satellites that are still active. We describe our methods, the data collected, our results, and our future plans.

  11. Mutual phenomena of the Galilean satellites: an analysis of the 1991 observations from VBO

    NASA Astrophysics Data System (ADS)

    Vasundhara, R.

    1994-01-01

    Results of analysis of seventeen mutual events, of the Galilean satellites, observed at the Vainu Bappu Observatory (VBO) during the 1991 are presented. The light curves were fitted with theoretical models to derive the relative astrometric positions of the satellites. The dependence of te derived parameters on the various light scattering laws are investigated. Results of the analysis indicate that for Io fits using Minnaert's and Lommel-Seeliger's laws are comparable however the Lambert's law solution fails to give good fit at the centre and at the wings of the light curves. The mean value of the Minnaert's parameter for this satellite derived from the good quality occulation of light curves in the I band is 0.559 +/- 0.11. Analysis of occulation light curves of 201 events using model with albedo variations inferred from Voyager imagery lead to best fit. An average residual of -340 +/- 10 km in the position of Io along its track relative to Europa compared to the E-3 ephemiris is noticed.

  12. Upper-Tropospheric Winds Derived from Geostationary Satellite Water Vapor Observations

    NASA Technical Reports Server (NTRS)

    Velden, Christopher S.; Hayden, Christopher M.; Nieman, Steven J.; Menzel, W. Paul; Wanzong, Steven; Goerss, James S.

    1997-01-01

    The coverage and quality of remotely sensed upper-tropospheric moisture parameters have improved considerably with the deployment of a new generation of operational geostationary meteorological satellites: GOES-8/9 and GMS-5. The GOES-8/9 water vapor imaging capabilities have increased as a result of improved radiometric sensitivity and higher spatial resolution. The addition of a water vapor sensing channel on the latest GMS permits nearly global viewing of upper-tropospheric water vapor (when joined with GOES and Meteosat) and enhances the commonality of geostationary meteorological satellite observing capabilities. Upper-tropospheric motions derived from sequential water vapor imagery provided by these satellites can be objectively extracted by automated techniques. Wind fields can be deduced in both cloudy and cloud-free environments. In addition to the spatially coherent nature of these vector fields, the GOES-8/9 multispectral water vapor sensing capabilities allow for determination of wind fields over multiple tropospheric layers in cloud-free environments. This article provides an update on the latest efforts to extract water vapor motion displacements over meteorological scales ranging from subsynoptic to global. The potential applications of these data to impact operations, numerical assimilation and prediction, and research studies are discussed.

  13. Satellite-based observations of unexpected coastal changes due to the Saemangeum Dyke construction, Korea.

    PubMed

    Lee, Yoon-Kyung; Ryu, Joo-Hyung; Choi, Jong-Kuk; Lee, Seok; Woo, Han-Jun

    2015-08-15

    Spatial and temporal changes around an area of conventional coastal engineering can be easily observed from field surveys because of the clear cause-and-effect observable in the before and after stages of the project. However, it is more difficult to determine environmental changes in the vicinity of tidal flats and coastal areas that are a considerable distance from the project. To identify any unexpected environmental impacts of the construction of Saemangeum Dyke in the area, we examined morphological changes identified by satellite-based observations through a field survey on Gomso Bay tidal flats (15km from Saemangeum Dyke), and changes in the suspended sediment distribution identified by satellite-based observations through a hydrodynamic analysis in the Saemangeum and Gomso coastal area. We argue that hydrodynamic changes due to conventional coastal engineering can affect the sedimentation pattern in the vicinity of tidal flats. We suggest that the environmental impact assessment conducted before a conventional coastal engineering project should include a larger area than is currently considered.

  14. Estimation of Transpiration and Water Use Efficiency Using Satellite and Field Observations

    NASA Technical Reports Server (NTRS)

    Choudhury, Bhaskar J.; Quick, B. E.

    2003-01-01

    Structure and function of terrestrial plant communities bring about intimate relations between water, energy, and carbon exchange between land surface and atmosphere. Total evaporation, which is the sum of transpiration, soil evaporation and evaporation of intercepted water, couples water and energy balance equations. The rate of transpiration, which is the major fraction of total evaporation over most of the terrestrial land surface, is linked to the rate of carbon accumulation because functioning of stomata is optimized by both of these processes. Thus, quantifying the spatial and temporal variations of the transpiration efficiency (which is defined as the ratio of the rate of carbon accumulation and transpiration), and water use efficiency (defined as the ratio of the rate of carbon accumulation and total evaporation), and evaluation of modeling results against observations, are of significant importance in developing a better understanding of land surface processes. An approach has been developed for quantifying spatial and temporal variations of transpiration, and water-use efficiency based on biophysical process-based models, satellite and field observations. Calculations have been done using concurrent meteorological data derived from satellite observations and four dimensional data assimilation for four consecutive years (1987-1990) over an agricultural area in the Northern Great Plains of the US, and compared with field observations within and outside the study area. The paper provides substantive new information about interannual variation, particularly the effect of drought, on the efficiency values at a regional scale.

  15. Global assessment of ocean carbon export by combining satellite observations and food-web models

    NASA Astrophysics Data System (ADS)

    Siegel, D. A.; Buesseler, K. O.; Doney, S. C.; Sailley, S. F.; Behrenfeld, M. J.; Boyd, P. W.

    2014-03-01

    The export of organic carbon from the surface ocean by sinking particles is an important, yet highly uncertain, component of the global carbon cycle. Here we introduce a mechanistic assessment of the global ocean carbon export using satellite observations, including determinations of net primary production and the slope of the particle size spectrum, to drive a food-web model that estimates the production of sinking zooplankton feces and algal aggregates comprising the sinking particle flux at the base of the euphotic zone. The synthesis of observations and models reveals fundamentally different and ecologically consistent regional-scale patterns in export and export efficiency not found in previous global carbon export assessments. The model reproduces regional-scale particle export field observations and predicts a climatological mean global carbon export from the euphotic zone of ~6 Pg C yr-1. Global export estimates show small variation (typically < 10%) to factor of 2 changes in model parameter values. The model is also robust to the choices of the satellite data products used and enables interannual changes to be quantified. The present synthesis of observations and models provides a path for quantifying the ocean's biological pump.

  16. Observations of the auroral hectometric radio emission onboard the INTERBALL-1 satellite

    NASA Astrophysics Data System (ADS)

    Kuril'Chik, V. N.

    2007-06-01

    The results of five-year (1995 2000) continuous observations of the auroral radio emission (ARE) in the hectometric wavelength range on the high-apogee INTERBALL-1 satellite are presented. Short intense bursts of the auroral hectometric radio emission (AHR) were observed at frequencies of 1463 and 1501 kHz. The bursts were observed predominantly at times when the terrestrial magnetosphere was undisturbed (in the quiet Sun period), and their number decreased rapidly with increasing solar activity. The bursts demonstrated seasonal dependence in the Northern and Southern hemispheres (dominating in the autumn-winter period). Their appearance probably depends on the observation time (UT). A qualitative explanation of the AHR peculiarities is given.

  17. Vegetation coupling to global climate: Trajectories of vegetation change and phenology modeling from satellite observations

    NASA Astrophysics Data System (ADS)

    Fisher, Jeremy Isaac

    Important systematic shifts in ecosystem function are often masked by natural variability. The rich legacy of over two decades of continuous satellite observations provides an important database for distinguishing climatological and anthropogenic ecosystem changes. Examples from semi-arid Sudanian West Africa and New England (USA) illustrate the response of vegetation to climate and land-use. In Burkina Faso, West Africa, pastoral and agricultural practices compete for land area, while degradation may follow intensification. The Nouhao Valley is a natural experiment in which pastoral and agricultural land uses were allocated separate, coherent reserves. Trajectories of annual net primary productivity were derived from 18 years of coarse-grain (AVHRR) satellite data. Trends suggested that pastoral lands had responded rigorously to increasing rainfall after the 1980's droughts. A detailed analysis at Landsat resolution (30m) indicated that the increased vegetative cover was concentrated in the river basins of the pastoral region, implying a riparian wood expansion. In comparison, riparian cover was reduced in agricultural regions. We suggest that broad-scale patterns of increasing semi-arid West African greenness may be indicative of climate variability, whereas local losses may be anthropogenic in nature. The contiguous deciduous forests, ocean proximity, topography, and dense urban developments of New England provide an ideal landscape to examine influences of climate variability and the impact of urban development vegetation response. Spatial and temporal patterns of interannual climate variability were examined via green leaf phenology. Phenology, or seasonal growth and senescence, is driven by deficits of light, temperature, and water. In temperate environments, phenology variability is driven by interannual temperature and precipitation shifts. Average and interannual phenology analyses across southern New England were conducted at resolutions of 30m (Landsat

  18. Intercomparison of surface heat transfer in the Arctic for multiple reanalyses, satellite data and field observations

    NASA Astrophysics Data System (ADS)

    Repina, Irina; Mazilkina, Alexandra; Ivanov, Vladimir

    2015-04-01

    This study evaluated surface heat fluxes from reanalyses (ERAInterim, NCEP/NCAR, ASR) in the Arctic Ocean during summer and fall. Several types of surface conditions are compared: very new ice cover during a period of low temperature, ice-free conditions, ice with leads and melt ponds, pack ice and marginal ice zone. Meteorological and micrometeorological observations were used to validate the temperature profiles and surface heat fluxes in the major reanalyses. We use data from Nansen and Amundsen basins observation system (NABOS) project to evaluate the performance of reanalyses forin the Arctic Ocean. The NABOS field experiment was carried out in the central part of the Arctic and in the eastern Arctic seas during summer and fall period of 2004-2009 and 2013. Compared data arrays are independent and sufficiently detailed to perform trustworthy evaluations. With the explicit treatment of the ice concentration, ERA-Interim generally reproduces the surface heat transfer, while NCEP/NCAR, based on a 55% concentration threshold, shows obvious disagreement with the observations in highly ice-covered and ice-free situations. The spatial and temporal patterns of the resulting flux fields are investigated and compared with those derived from satellite observations such as HOAPS, from blended data such as AOFLUX (in the open water cases). A computation of the sensible heat flux at the surface is formulated on the basis of spatial variations of the surface temperature estimated from satellite data. Based on the comparison of field experiments data, satellite-derived data and reanalysis the causes of underestimation of the values of turbulent heat fluxes in the Arctic modern reanalysis are investigated. Obtained differences are related to the temperature and structural inhomogeneity of the surface and the development of space-organized convection fields. Reanalyses data are sometimes used to calculate the surface heat budgets over polynyas to estimate ice production in

  19. Airborne Observations and Satellite Validation: INTEX-A Experience and INTEX-B Plans

    NASA Technical Reports Server (NTRS)

    Crawford, James H.; Singh, Hanwant B.; Brune, William H.; Jacob, Daniel J.

    2005-01-01

    Intercontinental Chemical Transport Experiment (INTEX; http://cloudl.arc.nasa.gov) is an ongoing two-phase integrated atmospheric field experiment being performed over North America (NA). Its first phase (INTEX-A) was performed in the summer of 2004 and the second phase (INTEX-B) is planned for the early spring of 2006. The main goal of INTEX-NA is to understand the transport and transformation of gases and aerosols on transcontinental/intercontinental scales and to assess their impact on air quality and climate. Central to achieving this goal is the need to relate space-based observations with those from airborne and surface platforms. During INTEX-A, NASA s DC-8 was joined by some dozen other aircraft from a large number of European and North American partners to focus on the outflow of pollution from NA to the Atlantic. Several instances of Asian pollution over NA were also encountered. INTEX-A flight planning extensively relied on satellite observations and in turn Satellite validation (Terra, Aqua, and Envisat) was given high priority. Over 20 validation profiles were successfully carried out. DC-8 sampling of smoke from Alaskan fires and formaldehyde over forested regions, and simultaneous satellite observations of these provided excellent opportunities for the interplay of these platforms. The planning for INTEX-5 is currently underway, and a vast majority of "standard" and "research" products to be retrieved from Aura instruments will be measured during INTEX-B throughout the troposphere. INTEX-B will focus on the inflow of pollution from Asia to North America and validation of satellite observations with emphasis on Aura. Several national and international partners are expected to coordinate activities with INTEX-B, and we expect its scope to expand in the coming months. An important new development involves partnership with an NSF-sponsored campaign called MIRAGE (Megacity Impacts on Regional and Global Environments- Mexico City Pollution Outflow Field

  20. Evaluating lateral boundary conditions in MATCH using retrieved observations from satellites

    NASA Astrophysics Data System (ADS)

    Andersson, Emma; Kahnert, Michael; Simpson, David; Devasthale, Abhay

    2015-04-01

    The role of hemispheric transport has gained large attention in regional chemical transport models due to its impact on both climate, air quality and visibility. The hemispheric transport in regional models are represented by the lateral boundary conditions (LBCs), where the inflow boundary specifies the domain beyond the model region and the outflow region will impact the stability of the advective transport solution. This study focuses on evaluating and implement LBCs from global chemical transport models for two important atmospheric tracers: carbon monoxide (CO) and ozone (O3). LBCs are derived from the hemispheric European Monitoring and Evaluation Programme (EMEP) model and the Model for Ozone and Related chemical Tracers (MOZART-4) over the time periods 2006-2012 and 2011-2012 respectively. Evaluation is done with observational data retrieved from the satellite sensors Measurements Of the Pollution In The Troposphere (MOPITT) and the Ozone Monitoring Instrument (OMI). The implementation of the LBCs is done in the regional chemical transport model Multiple scale atmospheric transport and chemistry (MATCH), developed by the Swedish Meteorological and Hydrological Institute (SMHI). The MATCH model is mostly used in simulations of the air quality over Europe on both on regional and local scales. In this study the model the domain is set over Europe. The LBC evaluation is done for the tropospheric column by smoothing the LBCs using satellite averaging kernels and a priori information. By retrieving the average profile for each month and lateral boundary, possible biases and also what global model that might be better suited for the LBCs in MATCH. The implementation will show how these biases proliferate through the MATCH model, and it will possibly be compared to satellite retrieved data from the sensor Atmospheric InfraRed Sounder (AIRS) inboard the satellite Aqua.

  1. Status and Future of Global Flood and Landslide Nowcasts and Forecasts Using Satellite Precipitation Observations (Invited)

    NASA Astrophysics Data System (ADS)

    Adler, R. F.; Wu, H.; Kirschbaum, D. B.; Policelli, F.; Hong, Y.; Tian, Y.; Pierce, H.

    2010-12-01

    The advent of quasi-global, real-time precipitation analyses has lead to the reality of running global hydrological models and algorithms for the estimation of the occurrence of floods and rain-induced landslides. These calculations provide information useful to national and international agencies in understanding the intensity, timeline and impact on populations of these significant hazard events. The quality of such applied hydrological estimations should improve with time due to continuation and improvement of multi-satellite precipitation observations through the Global Precipitation Measurement (GPM) program and the further development of the models and algorithms. This talk will summarize the results from the NASA-based, real-time flood and landslide nowcasts and forecasts and describe directions for improving results going into the GPM era. Global flood and landslide estimation systems have been running in real-time at 0.25° latitude/longitude resolution using multi-satellite rainfall analyses for several years, with results available through the TRMM website (trmm.gsfc.nasa.gov). Published evaluations of the current system indicate useful skill in comparison with global event inventories. The evaluations indicate higher skill for larger rainfall systems (e.g., tropical cyclone landfall vs. flash flood). This result is reasonable considering the resolution of the rainfall information (0.25° and 3-hr) and the resolution of the current models/algorithms (0.25°). Improvements over the next few years will include 1) better precipitation analyses utilizing space-time interpolations that maintain accurate intensity distributions, 2) improved rain estimation for shallow, orographic rainfall systems and some types of monsoon rainfall, 3) higher resolution landslide algorithms with combined physical/empirical approaches, 4) higher resolution flood models with accurate routing and regional calibration, and 5) use of satellite soil moisture for more accurate pre

  2. Contribution of Tropical Cyclones to the North Pacific Climatological Rainfall as Observed from Satellites

    NASA Technical Reports Server (NTRS)

    Rodgers, Edward B.; Adler, Robert F.; Pierce, Harold F.

    1997-01-01

    Tropical cyclone monthly rainfall amounts are estimated from passive microwave satellite observations for an eleven year period. These satellite-derived rainfall amounts are used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the North Pacific Ocean total rainfall during June-November when tropical cyclones are most important. To estimate these tropical cyclone rainfall amounts, mean monthly rain rates are derived from passive microwave satellite observations within 444 km radius of the center of those North Pacific tropical cyclones that reached storm stage and greater. These rain rate observations are converted to monthly rainfall amounts and then compared to those for non-tropical cyclone systems. The main results of this study indicate that: 1) tropical cyclones contribute 7% of the rainfall to the entire domain of the North Pacific during the tropical cyclone season and 12%, 3%, and 4% when the study area is limited to, respectively, the western, central, and eastern third of the ocean; 2) the maxima in tropical cyclone rainfall are poleward (5 deg to 10 deg latitude depending on longitude) of the maxima in non-tropical cyclone rainfall; 3) tropical cyclones contribute a maximum of 30% northeast of the Philippine Islands and 40% of the lower Baja California coast; 4) in the western North Pacific, the tropical cyclone rainfall lags the total rainfall by approximately two months and shows seasonal latitudinal variation following the ITCZ; and 5) in general, tropical cyclone rainfall is enhanced during the El Nino years by warm SSTs in the eastern North Pacific and by the monsoon trough in the western and central North Pacific.

  3. The combination of satellite observation techniques for sequential ionosphere VTEC modeling

    NASA Astrophysics Data System (ADS)

    Erdogan, Eren; Limberger, Marco; Schmidt, Michael; Seitz, Florian; Dettmering, Denise; Börger, Klaus; Brandert, Sylvia; Görres, Barbara; Kersten, Wilhelm F.; Bothmer, Volker; Hinrichs, Johannes; Venzmer, Malte; Mrotzek, Niclas

    2016-04-01

    The project OPTIMAP is a joint initiative by the Bundeswehr GeoInformation Centre (BGIC), the German Space Situational Awareness Centre (GSSAC), the German Geodetic Research Institute of the Technical University of Munich (DGFI-TUM) and the Institute for Astrophysics at the University of Göttingen (IAG). The main goal is to develop an operational tool for ionospheric mapping and prediction (OPTIMAP). A key feature of the project is the combination of different satellite observation techniques to improve the spatio-temporal data coverage and the sensitivity for selected target parameters. In the current status, information about the vertical total electron content (VTEC) is derived from the dual frequency signal processing of four techniques: (1) Terrestrial observations of GPS and GLONASS ensure the high-resolution coverage of continental regions, (2) the satellite altimetry mission Jason-2 is taken into account to provide VTEC in nadir direction along the satellite tracks over the oceans, (3) GPS radio occultations to Formosat-3/COSMIC are exploited for the retrieval of electron density profiles that are integrated to obtain VTEC and (4) Jason-2 carrier-phase observations tracked by the on-board DORIS receiver are processed to determine the relative VTEC. All measurements are sequentially pre-processed in hourly batches serving as input data of a Kalman filter (KF) for modeling the global VTEC distribution. The KF runs in a predictor-corrector mode allowing for the sequential processing of the measurements where update steps are performed with one-minute sampling in the current configuration. The spatial VTEC distribution is represented by B-spline series expansions, i.e., the corresponding B-spline series coefficients together with additional technique-dependent unknowns such as Differential Code Biases and Intersystem Biases are estimated by the KF. As a preliminary solution, the prediction model to propagate the filter state through time is defined by a random

  4. Intraannual variability of tides in the thermosphere from model simulations and in situ satellite observations

    NASA Astrophysics Data System (ADS)

    Häusler, K.; Hagan, M. E.; Forbes, J. M.; Zhang, X.; Doornbos, E.; Bruinsma, S.; Lu, G.

    2015-01-01

    In this paper, we provide insights into limitations imposed by current satellite-based strategies to delineate tidal variability in the thermosphere, as well as the ability of a state-of-the-art model to replicate thermospheric tidal determinations. Toward this end, we conducted a year-long thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) simulation for 2009, which is characterized by low solar and geomagnetic activity. In order to account for tropospheric waves and tides propagating upward into the ˜30-400 km model domain, we used 3-hourly MERRA (Modern-Era Retrospective Analysis for Research and Application) reanalysis data. We focus on exospheric tidal temperatures, which are also compared with 72 day mean determinations from combined Challenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) satellite observations to assess the model's capability to capture the observed tidal signatures and to quantify the uncertainties associated with the satellite exospheric temperature determination technique. We found strong day-to-day tidal variability in TIME-GCM that is smoothed out when averaged over as few as ten days. TIME-GCM notably overestimates the 72 day mean eastward propagating tides observed by CHAMP/GRACE, while capturing many of the salient features of other tidal components. However, the CHAMP/GRACE tidal determination technique only provides a gross climatological representation, underestimates the majority of the tidal components in the climatological spectrum, and moreover fails to characterize the extreme variability that drives the dynamics and electrodynamics of the ionosphere-thermosphere system. A multisatellite mission that samples at least six local times simultaneously is needed to provide this quantification.

  5. Observations of gravity waves from satellite and implications for the wave driving of the SAO

    NASA Astrophysics Data System (ADS)

    Ern, Manfred; Preusse, Peter; Riese, Martin

    2015-04-01

    The dynamics at low latitudes in the stratosphere and lower mesosphere is governed by an interplay of the quasi-biennial oscillation (QBO) and the semiannual oscillation (SAO) of the zonal wind. It is known that tropical dynamics has significant influence on the atmosphere over a large range of altitudes and latitudes. For example, QBO and SAO effects are seen in the MLT region, and there is a significant influence of the QBO on surface weather and climate in the Northern Hemisphere during winter. Still, global models have large difficulties in simulating a realistic QBO and SAO. One main uncertainty is the wave driving of these oscillations, in particular the driving by gravity waves (GWs). We derive GW temperature variances, GW momentum fluxes and potential GW drag from over three years of High Resolution Dynamics Limb Sounder (HIRDLS) satellite data in the stratopause region. These observations are compared with the SAO driving due to planetary waves, as well as the zonal wind tendencies, both determined from the ECMWF ERA-Interim (ERAI) reanalysis. HIRDLS satellite observations and ERAI support the general assumption that, due to selective filtering of the GW spectrum by the QBO in the stratosphere, GWs mainly contribute to the SAO momentum budget during SAO eastward wind shear. However, during SAO westward wind shear the GW contribution is usually smaller, and the wave driving is dominated by planetary waves, probably of extratropical origin. Still, we find indications in both satellite observations and ERAI that sometimes GW drag is important also during SAO westward wind shear.

  6. Observing a Severe Dust Storm Event over China using Multiple Satellite Data

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Xue, Yong; Guang, Jie; Mei, Linlu

    2013-04-01

    A severe dust storm (SDS) event occurred from 19 to 21 March 2010 in China, originated in western China and Mongolia and propagated into eastern/southern China, affecting human's life in a large area. As reported by National Meteorological Center of CMA (China Meteorological Administration), 16 provinces (cities) of China were hit by the dust storm (Han et al., 2012). Satellites can provide global measurements of desert dust and have particular importance in remote areas where there is a lack of in situ measurements (Carboni et al., 2012). To observe a dust, it is necessary to estimate the spatial and temporal distributions of dust aerosols. An important metric in the characterisation of aerosol distribution is the aerosol optical depth (AOD) (Adhikary et al., 2008). Satellite aerosol retrievals have improved considerably in the last decade, and numerous satellite sensors and algorithms have been generated. Reliable retrievals of dust aerosol over land were made using POLarization and Directionality of the Earth's Reflectance instrument-POLDER (Deuze et al., 2001), Moderate Resolution Imaging Spectroradiometer-MODIS (Kaufman et al., 1997; Hsu et al., 2004), Multiangle Imaging Spectroradiometer-MISR (Martonchik et al., 1998), and Cloud-aerosol Lidar and infrared pathfinder satellite observations (CALIPSO). However, intercomparison exercises (Myhre et al., 2005) have revealed that discrepancies between satellite measurements are particularly large during events of heavy aerosol loading. The reason is that different AOD retrieval algorithms make use of different instrument characteristics to obtain retrievals over bright surfaces. For MISR, POLDER and MODIS instrument, the multi-angle approaches, the polarization measurements and single-view approaches were used to retrieval AOD respectively. Combining of multi-sensor AOD data can potentially create a more consistent, reliable and complete picture of the space-time evolution of dust storms (Ehlers, 1991). In order to

  7. Using satellite observations to quantify biomass burning emissions of NOx, and hydrocarbons in the Tropics

    NASA Technical Reports Server (NTRS)

    Jaegle, Lyatt

    2005-01-01

    This is the final report for "Using satellite observations to quantify biomass burning emissions of NOx and hydrocarbons in the Tropics", funded through the New Investigator Program between March 2001 and March 2005. This period includes a 1-year no-cost extension of the original award. This report summarizes our accomplishments during the duration of the grant. Section 2 focuses on the research component of this work, while section 3 describes the education component. The personnel supported under this project is given in section 4. Section 5 lists publications resulting from NASA support and section 6 provides a list of conferences and seminars where the results were presented.

  8. The High Visible Resolution (HVR) instrument of the spot ground observation satellite

    NASA Technical Reports Server (NTRS)

    Otrio, G.

    1980-01-01

    Two identical high resolution cameras, capable of attaining a track width of 116 km in an almost vertical line of sight from the two 60 km images of each instrument, will be carried on the initial mission of the space observation of Earth satellite (SPOT). Specifications for the instrument, including the telescope and CCD devices are summarized. The present status of development is described including the optical characteristics, structure and thermal control, detector assembly, electronic equipment, and calibration. SPOT mission objectives include the developments relating to soil use, the exploration of EART Earth resources, the discrimination of plant species, and cartography.

  9. Synergy of Satellite-Surface Observations for Studying the Properties of Absorbing Aerosols in Asia

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee

    2010-01-01

    Through interaction with clouds and alteration of the Earth's radiation budget, atmospheric aerosols significantly influence our weather and climate. Monsoon rainfalls, for example, sustain the livelihood of more than half of the world's population. Thus, understanding the mechanism that drives the water cycle and freshwater distribution is high-lighted as one of the major near-term goals in NASA's Earth Science Enterprise Strategy. Every cloud droplet/ice-crystal that serves as an essential element in portraying water cycle and distributing freshwater contains atmospheric aerosols at its core. In addition, the spatial and temporal variability of atmospheric aerosol properties is complex due to their dynamic nature. In fact, the predictability of the tropical climate system is much reduced during the boreal spring, which is associated with the peak season of biomass burning activities and regional/long-range transport of dust aerosols. Therefore, to accurately assess the impact of absorbing aerosols on regional-to-global climate requires not only modeling efforts but also continuous observations from satellites, aircraft, networks of ground-based instruments and dedicated field experiments. Since 1997 NASA has been successfully launching a series of satellites the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite

  10. The continuous spectrum of Markarian 421 during periods of X-ray satellite observations

    NASA Technical Reports Server (NTRS)

    Mufson, S. L.; Wood, K.; Mcnutt, D. P.; Yentis, D. J.; Meekins, J. F.; Byram, E. T.; Chubb, T. A.; Friedman, H.; Wisniewski, W. Z.

    1980-01-01

    New UBVRI photometry of Mrk 421 obtained during periods of X-ray satellite observations are presented. An X-ray light curve for 1977 November from the HEAO A-1 experiment is also given. The decomposition of the UBVR fluxes into a compact nonthermal component and an extended galactic component shows that there are coordinated variations in the optical nonthermal and X-ray emission. The data are consistent with the hypothesis that the mini-BL Lac object is emitting by the synchrontron-self-Compton process. The host galaxy of this composite source has properties like those of a giant elliptical.

  11. Comparing satellite- to ground-based automated and manual cloud coverage observations - a case study

    NASA Astrophysics Data System (ADS)

    Werkmeister, A.; Lockhoff, M.; Schrempf, M.; Tohsing, K.; Liley, B.; Seckmeyer, G.

    2015-05-01

    In this case study we compare cloud fractional cover measured by radiometers on polar satellites (AVHRR) and on one geostationary satellite (SEVIRI) to ground-based manual (SYNOP) and automated observations by a cloud camera (Hemispherical Sky Imager, HSI). These observations took place in Hannover, Germany, and in Lauder, New Zealand, over time frames of 3 and 2 months, respectively. Daily mean comparisons between satellite derivations and the ground-based HSI found the deviation to be 6 ± 14% for AVHRR and 8 ± 16% for SEVIRI, which can be considered satisfactory. AVHRR's instantaneous differences are smaller (2 ± 22%) than instantaneous SEVIRI cloud fraction estimates (8 ± 29%) when compared to HSI due to resolution and scenery effect issues. All spaceborne observations show a very good skill in detecting completely overcast skies (cloud cover ≥ 6 oktas) with probabilities between 92 and 94% and false alarm rates between 21 and 29% for AVHRR and SEVIRI in Hannover, Germany. In the case of a clear sky (cloud cover lower than 3 oktas) we find good skill with detection probabilities between 72 and 76%. We find poor skill, however, whenever broken clouds occur (probability of detection is 32% for AVHRR and 12% for SEVIRI in Hannover, Germany). In order to better understand these discrepancies we analyze the influence of algorithm features on the satellite-based data. We find that the differences between SEVIRI and HSI cloud fractional cover (CFC) decrease (from a bias of 8 to almost 0%) with decreasing number of spatially averaged pixels and decreasing index which determines the cloud coverage in each "cloud-contaminated" pixel of the binary map. We conclude that window size and index need to be adjusted in order to improve instantaneous SEVIRI and AVHRR estimates. Due to its automated operation and its spatial, temporal and spectral resolution, we recommend as well that more automated ground-based instruments in the form of cloud cameras should be installed

  12. Optimization of satellite coverage in observing cause and effect changes in the ionosphere, magnetosphere, and solar wind. Master's thesis

    SciTech Connect

    Loveless, M.J.

    1993-06-01

    Disturbances in the ionosphere sometimes cause adverse effects to communications systems, power grids, etc. on the earth. Currently, very little, if any, lead time is given to warn of an impending problem. If a forecast could be made of ionospheric occurrences, some lead time may be given to appropriate agencies and equipment may be saved. Most changes that occur in the ionosphere are a result of interaction of energy, currents, etc. between the magnetosphere and/or solar wind. Before a forecast can be made, however, improvement of ionospheric models currently in use need to be made. The models currently depict features in various regions of the ionosphere but not always where these features are actually observed. So an improvement to the model is needed to create an accurate baseline condition, or in other words an accurate depiction of the current ionosphere. Models could be improved by inputting real-time data from the ionosphere into the model. This data would come from satellites and/or ground-based stations.

  13. SatCam: A mobile application for coordinated ground/satellite observation of clouds and validation of satellite-derived cloud mask products.

    NASA Astrophysics Data System (ADS)

    Gumley, L.; Parker, D.; Flynn, B.; Holz, R.; Marais, W.

    2011-12-01

    SatCam is an application for iOS devices that allows users to collect observations of local cloud and surface conditions in coordination with an overpass of the Terra, Aqua, or NPP satellites. SatCam allows users to acquire images of sky conditions and ground conditions at their location anywhere in the world using the built-in iPhone or iPod Touch camera at the same time that the satellite is passing overhead and viewing their location. Immediately after the sky and ground observations are acquired, the application asks the user to rate the level of cloudiness in the sky (Completely Clear, Mostly Clear, Partly Cloudy, Overcast). For the ground observation, the user selects their assessment of the surface conditions (Urban, Green Vegetation, Brown Vegetation, Desert, Snow, Water). The sky condition and surface condition selections are stored along with the date, time, and geographic location for the images, and the images are uploaded to a central server. When the MODIS (Terra and Aqua) or VIIRS (NPP) imagery acquired over the user location becomes available, a MODIS or VIIRS true color image centered at the user's location is delivered back to the SatCam application on the user's iOS device. SSEC also proposes to develop a community driven SatCam website where users can share their observations and assessments of satellite cloud products in a collaborative environment. SSEC is developing a server side data analysis system to ingest the SatCam user observations, apply quality control, analyze the sky images for cloud cover, and collocate the observations with MODIS and VIIRS satellite products (e.g., cloud mask). For each observation that is collocated with a satellite observation, the server will determine whether the user scored a "hit", meaning their sky observation and sky assessment matched the automated cloud mask obtained from the satellite observation. The hit rate will be an objective assessment of the accuracy of the user's sky observations. Users with

  14. A Comparison of Theory and Observation of the Echo I Satellite

    NASA Technical Reports Server (NTRS)

    Bryant, R. W.

    1961-01-01

    Observations of the Echo I balloon satellite have been compared with a theory including the following perturbing effects: (1) solar radiation pressure; (2) lunar and solar gravitation; (3) second, third, and fourth harmonics of the earth's gravitational potential; and (4) atmospheric drag. With a set of orbital elements at the 26th day of the lifetime of the satellite, it was possible to match the observational data to 180 days with root mean square residuals as follows: Delta-a = 17.9 km, Delta-e = 0.0021, Delta-i = 0.0177 deg., Delta-omega = 1.1231 deg., Delta-Omega = 0.4821 deg., Delta-perigee height = 7.50 km. No differential correction has been applied as yet. Values of atmospheric density between 1500 and 930 km, assuming neutral drag effects only, have been inferred from the orbital data. The connection between solar activity and drag is also examined. As the Echo I perigee height continues to oscillate between 900 and 1500 km, more valuable orbital data will be obtained and atmospheric properties will be deduced. Further refinements in the mathematical model, especially in a time-dependent model atmosphere, should bring a substantial reduction in the residuals of the observations.

  15. Constraining cloud lifetime effects of aerosols using A-Train satellite observations

    SciTech Connect

    Wang, Minghuai; Ghan, Steven J.; Liu, Xiaohong; Ecuyer, Tristan L.; Zhang, Kai; Morrison, H.; Ovchinnikov, Mikhail; Easter, Richard C.; Marchand, Roger; Chand, Duli; Qian, Yun; Penner, Joyce E.

    2012-08-15

    Aerosol indirect effects have remained the largest uncertainty in estimates of the radiative forcing of past and future climate change. Observational constraints on cloud lifetime effects are particularly challenging since it is difficult to separate aerosol effects from meteorological influences. Here we use three global climate models, including a multi-scale aerosol-climate model PNNL-MMF, to show that the dependence of the probability of precipitation on aerosol loading, termed the precipitation frequency susceptibility (S{sub pop}), is a good measure of the liquid water path response to aerosol perturbation ({lambda}), as both Spop and {lambda} strongly depend on the magnitude of autoconversion, a model representation of precipitation formation via collisions among cloud droplets. This provides a method to use satellite observations to constrain cloud lifetime effects in global climate models. S{sub pop} in marine clouds estimated from CloudSat, MODIS and AMSR-E observations is substantially lower than that from global climate models and suggests a liquid water path increase of less than 5% from doubled cloud condensation nuclei concentrations. This implies a substantially smaller impact on shortwave cloud radiative forcing (SWCF) over ocean due to aerosol indirect effects than simulated by current global climate models (a reduction by one-third for one of the conventional aerosol-climate models). Further work is needed to quantify the uncertainties in satellite-derived estimates of S{sub pop} and to examine S{sub pop} in high-resolution models.

  16. Evaluating the Application of Multi-Satellite Observations in Hydrologic Modeling

    NASA Technical Reports Server (NTRS)

    Bolten, John

    2011-01-01

    When monitoring local or regional hydrosphere dynamics for applications such as agricultural productivity or drought and flooding events, it is necessary to have accurate, high-resolution estimates of terrestrial water and energy storages. Though in-situ observations provide reliable estimates of hydrologic states and fluxes, they are only capable of accurately capturing the dynamics at relatively discrete points in space and time, which makes them inadequate for characterizing the variability of the water budget across scales. In contrast, satellite-based remote sensing is ideal for providing observations of hydrological states and fluxes because it provides spatially-distributed observations at spatial and temporal scales required for regional land surface process modeling. Due to the continued progress in algorithm development and emerging satellite technology, we now have near-real time monitoring of several components of the water cycle including precipitation, soil moisture, lake and river height, terrestrial water storage, snow cover, and evapotranspiration. As these data become more readily available, their application to hydrologic modeling is becoming more common, however there remains little consensus on the most appropriate method for optimal integration and evaluation in regard to hydrological applications. Here we present two case studies operationally applying several remotely sensed products from AMSR-E, GRACE, and MODIS and discuss assimilation strategies, ease of integration and interpretation, and methods for quantifying the success of the application methodology.

  17. Constraining cloud lifetime effects of aerosols using A-Train satellite observations

    NASA Astrophysics Data System (ADS)

    Wang, Minghuai; Ghan, Steven; Liu, Xiaohong; L'Ecuyer, Tristan S.; Zhang, Kai; Morrison, Hugh; Ovchinnikov, Mikhail; Easter, Richard; Marchand, Roger; Chand, Duli; Qian, Yun; Penner, Joyce E.

    2012-08-01

    Aerosol indirect effects have remained the largest uncertainty in estimates of the radiative forcing of past and future climate change. Observational constraints on cloud lifetime effects are particularly challenging since it is difficult to separate aerosol effects from meteorological influences. Here we use three global climate models, including a multi-scale aerosol-climate model PNNL-MMF, to show that the dependence of the probability of precipitation on aerosol loading, termed the precipitation frequency susceptibility (Spop), is a good measure of the liquid water path response to aerosol perturbation (λ), as both Spop and λ strongly depend on the magnitude of autoconversion, a model representation of precipitation formation via collisions among cloud droplets. This provides a method to use satellite observations to constrain cloud lifetime effects in global climate models. Spop in marine clouds estimated from CloudSat, MODIS and AMSR-E observations is substantially lower than that from global climate models and suggests a liquid water path increase of less than 5% from doubled cloud condensation nuclei concentrations. This implies a substantially smaller impact on shortwave cloud radiative forcing over ocean due to aerosol indirect effects than simulated by current global climate models (a reduction by one-third for one of the conventional aerosol-climate models). Further work is needed to quantify the uncertainties in satellite-derived estimates of Spop and to examine Spop in high-resolution models.

  18. Emergency satellite observation and assessment of a glacier lake outburst flood in Bhutan

    NASA Astrophysics Data System (ADS)

    Nagai, Hiroto; Tadono, Takeo; Suzuki, Shinichi

    2016-04-01

    Following a glacial lake outburst flood (GLOF) on Jun. 28, 2015, in western Bhutan, the Japan Aerospace Exploration Agency performed an emergency observation on Jul. 2, 2015 using the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) onboard the Advanced Land Observing Satellite-2 (ALOS-2, "DAICHI-2"). Based on a dataset generated from the Advanced Land Observing Satellite (ALOS) imagery, "The Glacial Lake Inventory of Bhutan using ALOS Data", the glacier lake that potentially contributed to this GLOF were identified at 28°4'7.7"N, 89°34'50.0"E, in a headwater of the Mo Chu river basin, western Bhutan. A post-event lake outline was delineated manually using the acquired PALSAR-2 image. Pre-event outlines were delineated from previously acquired PALSAR-2 images (Apr. 23, 2015), Landsat 8 (Mar. 8, 2015), and ALOS (Dec. 22, 2010). The differences between these outlines reveal a remarkable expansion (+48.0%) from Mar. 8 to Apr. 23, 2015, followed by a remarkable shrinkage (‑52.9%) from Apr. 23 to Jul. 2, 2015. This result indicates the lake to be a highly likely source of the flood. Topographically, it is located at a glacier terminus, surrounded by a moraine. Differing backscatter patterns between successive PALSAR-2 images in a certain part of the moraine suggest that it underwent some collapse, possibly as a result of the GLOF. More detailed investigations, including field surveys, are necessary to fully reveal and understand this event.

  19. Utility of Satellite Magnetic Observations for Estimating Near-Surface Magnetic Anomalies

    NASA Technical Reports Server (NTRS)

    Kim, Hyung Rae; vonFrese, Ralph R. B.; Taylor, Patrick T.; Kim, Jeong Woo; Park, Chan Hong

    2003-01-01

    Regional to continental scale magnetic anomaly maps are becoming increasingly available from airborne, shipborne, and terrestrial surveys. Satellite data are commonly considered to fill the coverage gaps in regional compilations of these near-surface surveys. For the near-surface Antarctic magnetic anomaly map being produced by the Antarctic Digital Magnetic Anomaly Project (ADMAP), we show that near-surface magnetic anomaly estimation is greatly enhanced by the joint inversion of the near-surface data with the satellite observations relative to the conventional technique such as minimum curvature. Orsted observations are especially advantageous relative to the Magsat data that have order-of-magnitude greater measurement errors, albeit at much lower orbital altitudes. CHAMP is observing the geomagnetic field with the same measurement accuracy as the Orsted mission, but at the lower orbital altitudes covered by Magsat. Hence, additional significant improvement in predicting near-surface magnetic anomalies can result as these CHAMP data are available. Our analysis also suggests that considerable new insights on the magnetic properties of the lithosphere may be revealed by a further order-of-magnitude improvement in the accuracy of the magnetometer measurements at minimum orbital altitude.

  20. Effect of different spatial resolution of satellite image to observe the forest condition using satellite image and National Forest Inventory data

    NASA Astrophysics Data System (ADS)

    Kajisa, T.; Mizoue, N.; Yoshida, S.

    2010-12-01

    One of the most substantial needs in forest management planning is information about the condition of the forest. Strategic decisions concerning timber policies, decisions about timing and spatial extent of forest operations, and operational decisions such as work plans are all examples where accurate information of the forest conditions are required. Landsat has played the important role for land cover observation in the past, but, got a serious problem. Currently, many kinds of satellite image are available to monitor land cover. So, the utility of different types of satellite image have to be evaluated for land cover monitoring. On the other hands, in Japan, National Forest Inventory (NFI) has been conducted since 1999 with the aim of understanding the state and dynamics of various aspects in forests such as wood production and biodiversity throughout the country. However, few studies have been conducted to combine the satellite image and NFI data. Therefore, the objective of this study was to evaluate the effect of different spatial resolution of satellite image to observe the forest condition (forest/non-forest, forest types, forest stand volume) using satellite image and NFI data.

  1. Observation of satellite peaks and dips in the scattering of light in a double-pass geometry.

    PubMed

    Méndez, E R; Chaikina, E I; Escamilla, H M

    1999-06-01

    We report the experimental observation of enhanced backscattering and satellite peaks and dips in light scattered by a system that involves double passage of waves through a random-phase screen and a birefringent crystal.

  2. Spectral signatures of the ionospheric Alfvén resonator to be observed by low-Earth orbit satellite

    NASA Astrophysics Data System (ADS)

    Surkov, V. V.; Pilipenko, V. A.

    2016-03-01

    Interference of an incident and reflected Alfvén pulses propagating inside the ionospheric Alfvén resonator (IAR) is studied on the basis of a simple one-dimensional model. Particular emphasis has been placed on the analysis of spectral features of ultralow frequency (˜1-15 Hz) electric perturbations recently observed by Communications/Navigation Outage Forecasting System satellite. This "fingerprint" multiband spectral structure was observed when satellite descended in the terminator vicinity. Among factors affecting spectral structure the satellite position and distance from the IAR boundaries are most significant. It is concluded that the observed spectrograms exhibit modulation with "period" depending on propagation delay time of reflected Alfvén pulses in such a way that this effect can mask a spectral resonance structure resulted from excitation of IAR eigenmodes. The proposed interference effect is capable to produce a spectral pattern resembling a fingerprint which is compatible with the satellite observations.

  3. International Ultraviolet Explorer satellite observations of seven high-excitation planetary nebulae.

    PubMed

    Aller, L H; Keyes, C D

    1980-03-01

    Observations of seven high-excitation planetary nebulae secured with the International Ultraviolet Explorer (IUE) satellite were combined with extensive ground-based data to obtain electron densities, gas kinetic temperatures, and ionic concentrations. We then employed a network of theoretical model nebulae to estimate the factors by which observed ionic concentrations must be multiplied to obtain elemental abundances. Comparison with a large sample of nebulae for which extensive ground-based observations have been obtained shows nitrogen to be markedly enhanced in some of these objects. Possibly most, if not all, high-excitation nebulae evolve from stars that have higher masses than progenitors of nebulae of low-to-moderate excitation. PMID:16592781

  4. The use of satellite observations of the ocean surface in commercial fishing operations

    NASA Technical Reports Server (NTRS)

    Montgomery, D. R.

    1983-01-01

    Commercial fishermen are interested in the safety of their crews, boats, and gear, and in making the best catch for their time and money. Rising fuel costs, increased competition from foreign fisheries, improved knowledge about fish habits and the new 200 mile economic zone have all had an impact on the U.S. fishing industry. As a consequence, the modern fisherman, more than ever, requires reliable and timely information about the marine environment. This paper describes an experimental program to utilize satellite observations of the ocean surface, in conjunction with conventional observations and products, to prepare special fisheries aids charts for daily radio facsimile broadcasts to commercial fishermen. These special fisheries products aggregate a broad set of ocean observations, including ocean color structure, to depict oceanographic conditions of importance to commercial fishing tactics. Results to date have shown that improved safety at sea and decreased fuel costs can be achieved through the applied use of these special fisheries charts.

  5. MAPIR: An Airborne Polarmetric Imaging Radiometer in Support of Hydrologic Satellite Observations

    NASA Technical Reports Server (NTRS)

    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.

  6. Coherent Backscattering Effect in Saturnian vs. Uranian Satellites: Observations and Enhanced MSTM Modeling

    NASA Astrophysics Data System (ADS)

    Pitman, Karly M.; Kolokolova, Ludmilla; Verbiscer, Anne J.; Joseph, Emily C.; Mackowski, Daniel W.; Buratti, Bonnie J.; Momary, Thomas W.

    2014-11-01

    We continue our campaign to extract spectra and measure absorption band parameters from Cassini Visual & Infrared Mapping Spectrometer (VIMS) and ground-based near-infrared observations of saturnian and uranian icy satellites. We compare these spectra to numerical models to study the coherent backscattering effect (CBE; constructive interference of radiation) that should significantly alter the interpretation of spacecraft spectra obtained at solar phase angles α < 2 degrees. To quantify CBE, we extract VIMS spectra for different α from the same location on the icy satellite surface, ideally within +/- 1-2 degrees in subspacecraft latitude and longitude. Using 2013-2014 calibration updates for VIMS, we present groups of VIMS spectra (pairs or trios) for 3 saturnian moons that most closely fit these ideal criteria. We also show models of the light-scattering characteristics of icy surfaces using a new version of the Multiple Sphere T-Matrix (MSTM) code (Mackowski, D., 2014, in Proceedings of the Workshop “Scattering by aggregates (on surfaces)”, Bremen, Germany, 24 - 25. March 2014, p. 6-9). This code, called MSTM4, allows users to build large, thick slabs of dozens of thousands of spheres to model planetary regolith more accurately. The results clearly indicate the influence of CBE on the spectra and show significant dependence on the size of particles and their packing. To extend the low phase angle coverage of Cassini VIMS data and examine CBE on darker surfaces, we also compare to spectra of several uranian satellites (Titania, Oberon Ariel) acquired using Triplespec ( 3500) at Apache Point Observatory, New Mexico. Synthesizing such results will ultimately place limits on the size and packing fraction of icy satellite regolith particles and aid in interpretations of the structure, composition, and evolution of icy satellites.This work is supported by NASA’s Outer Planets Research program (NNX12AM76G; PI Pitman), Planetary Astronomy program (NNX09AD06G

  7. Observations of El Niño impacts using in situ GLOBE protocols and satellite data

    NASA Astrophysics Data System (ADS)

    Srinivasan, M. M.; Destaerke, D.

    2015-12-01

    The El Niño phenomenon is a periodic ocean condition that occurs every two to ten years in the central and east-central equatorial Pacific Ocean. It alters the normal patterns of ocean circulation, surface temperature, and evaporation, causing noticeable and often severe changes in weather conditions in many areas of the world. El Niño is the warm phase of the El Niño Southern Oscillation (ENSO), and usually reaches its peak between December and February time period. El Niño and its worldwide consequences are studied by the school network of the GLOBE Program (www.globe.gov) which brings together students, teachers, and scientists in support of student research and validation of international Earth science research projects. Since the start of the GLOBE Program over 20 years ago, GLOBE classrooms utilize carefully developed daily, weekly, or seasonally protocols such as maximum, minimum and current temperatures, rainfall, soil moisture, and others, to measure changes in the environment. The data collected by the students is entered in an online GLOBE database. In addition to the student-contributed data, automated stations also collect and send measurements to the GLOBE database.Students compare their data with global data acquired by satellites to help validate the satellite data. With a potentially historic-level El Niño event thought to be on the horizon--possibly one of the strongest in 50 years—we will propose an emphasis on measurements from GLOBE schools that will support studies and satellite observations of El Niño. We plan to provide the schools with additional satellite data sets such as ocean temperature measurements from Advanced Very High Resolution Radiometer (AVHRR), sea surface elevation measurements from Jason-2 and 3 (after it launches), and others to be identified. We wish to address and support the following educational objectives: - Demonstrate how El Niño affects local precipitation and temperature across the globe, - Link teachers

  8. The evolution of Earth Observation satellites in Europe and its impact on the performance of emergency response services

    NASA Astrophysics Data System (ADS)

    Denis, Gil; de Boissezon, Hélène; Hosford, Steven; Pasco, Xavier; Montfort, Bruno; Ranera, Franck

    2016-10-01

    The paper reviews the evolution of Earth Observation systems in Europe and Worldwide and analyses the potential impact of their performance in support of emergency response services. Earth Observation