3. WEST APPROACH AND GUARDRAIL LOOKING SOUTHEAST, IDOT BRIDGE INSPECTION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. WEST APPROACH AND GUARDRAIL LOOKING SOUTHEAST, IDOT BRIDGE INSPECTION TEAM IN BACKGROUND. - Illinois Central Railroad Overpass, Spanning Illinois Central Railroad at U.S. Highway 20, Ackley, Hardin County, IA

LANDSAT-D band 6 data evaluation

NASA Technical Reports Server (NTRS)

1982-01-01

A filter, fabricated to match the spectral response of the LANDSAT band 6 sensors, was received and the combined system response function computed. The half power points for the aircraft system are 10.5 micrometer and 11.55 micrometer compared to the 10.4 and 11.6 micrometer values for the satellite. These discrepancies are considered acceptable; their effect on the apparent temperature observed at the satellite is being evaluated. The filter was installed in the infrared line scanner and the line scanner was installed in the aircraft and field checked. A daytime underflight of the satellite is scheduled for the next clear overpass and the feasibility of a nightime overpass is being discussed with NASA. The LOWTRAN 5 computer code was obtained from the Air Force Geophysical Laboratory and is being implemented for use on this effort.

Performance testing of HPC on Sunshine Bridge.

DOT National Transportation Integrated Search

2009-09-01

The deck of the Sunshine Bridge overpass, located westbound on Interstate 40 (I-40) near Winslow, Arizona, was : replaced on August 24, 2005. The original deteriorated concrete deck was replaced using high performance : concrete (HPC), reinforced wit...

Pronghorn and Mule Deer Use of Underpasses and Overpasses Along US Highway 191, Wyoming

DOT National Transportation Integrated Search

2015-09-01

The seasonal migrations of ungulates are increasingly threatened by various forms of anthropogenic disturbance, including roads, fences, and other infrastructure. While roadway impacts (i.e., wildlifevehicle collisions and landscape permeability) ...

Evaluation of the suitability of Skylab data for the purpose of petroleum exploration

NASA Technical Reports Server (NTRS)

Collins, R. J. (Principal Investigator); Petzel, G.; Everett, J. R.

1975-01-01

The author has identified the following significant results. Comparisons of the various photographic bands of Skylab imagery indicate that, overall, standard color (particularly S190B) is the most valuable for geological purposes. Detailed examination of all bands indicates that as with ERTS imagery each band contains useful information that is unique to it. The results of geological interpretations based on ERTS and Skylab imagery are strikingly similar. It appears that more information can be extracted from a single Skylab overpass than a single ERTS overpass, but that with repeated passes the lower resolution ERTS imagery may yield information comparable to that contained in S190B imagery. Comparison of Skylab photography to high altitude aircraft photography suggests that there are distinct advantages to using Skylab imagery for regional geologic interpretations. This is primarily because of the synoptic view provided by the space acquired imagery allows and encourages integration of regional geologic features.

Deer Creek Dam, Hydroelectric Powerplant, 868 feet/291 degrees from intersection ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Deer Creek Dam, Hydroelectric Powerplant, 868 feet/291 degrees from intersection of dam complex access road with U.S. Highway 189, 1,340 feet/352 degrees from the dam spillway overpass, Charleston, Wasatch County, UT

Luminaire vibration suppression study : final report.

DOT National Transportation Integrated Search

1974-03-01

This study was initiated to find solutions to problems of inadequate lamp life in luminaires located on the state's bridges and overpasses. Since the problem was known to be caused by excess traffic vibration reaching the bulbs, an investigation of t...

State Highway 9 wildlife crossings monitoring – annual report year 1.

DOT National Transportation Integrated Search

2017-02-02

This research evaluates the effectiveness of the SH 9 Colorado River South Wildlife & Safety Improvement Project, including two wildlife overpasses, and five wildlife underpasses connected with 10.4 miles of wildlife exclusion fencing in Grand County...

Interaction between drilled shaft and mechanically stabilized earth (MSE) wall : technical report.

DOT National Transportation Integrated Search

2017-04-01

Drilled shafts are being constructed within the reinforced zone of mechanically stabilized earth (MSE) walls especially in the case of overpass bridges where the drilled shafts carry the bridge deck or traffic signs. The interaction between the drill...

Implementation of heat-straightening repairs for Louisiana bridges.

DOT National Transportation Integrated Search

1998-12-01

The goal of this study was to implement the latest heat-straightening repair technology on a Louisiana Bridge. The bridge chosen was an overpass just east of Lake Charles crossing 1-10. Working with both state and district personnel, the bridge was r...

Initial Results from CASSIOPE/ePOP Satellite Overpasses above HAARP in 2014

NASA Astrophysics Data System (ADS)

Siefring, C. L.; Bernhardt, P. A.; Briczinski, S. J., Jr.; James, H. G.; Yau, A. W.; Knudsen, D. J.

2015-12-01

The High Frequency Active Auroral Research Program (HAARP) facility was operated in conjunction with overpasses of the enhanced Polar Outflow Probe (ePOP) instruments on the Canadian CASSIOPE satellite. During these overpasses HAARP was operated in several different heating modes and regimes as diagnosed by the characteristics of Stimulated Electromagnetic Emissions (SEE) using ground-based receivers while simultaneously ePOP monitored in-situ HF and VLF signals, looked for ion and electron heating, and provided VHF and UHF signals for propagation effects studies. The e-POP suite of instruments and particularly the ePOP Radio Receiver Instrument (RRI) offer a unique combination diagnostics appropriate for studying the non-linear plasma effects generated high-power HF waves in the ionosphere. In this presentation, the initial results from ePOP observations from two separate 2014 measurement campaigns at HAARP (April 16 to April 29 and May 25 to June 9) will be discussed. Several innovative experiments were performed during the campaign. Experiments explored a wide range of ionospheric effects. These include: 1) Penetration of HF pump waves into the ionosphere via large and small scale irregularities, 2) effects of gyro-harmonic heating and artificial ionization layers, 3) effects of HAARP beam shape with O- and X-mode transmissions, 4) coupling of Lower Hybrid modes into Whistler waves, 5) D/E-region VLF generation in the ionosphere using VLF modulation of the HF pump 6) scattering of VHF and UHF signals and 7) scattering and non-linear modulation of a 9.5 MHz probe wave propagating through the region of the ionosphere modified by HAARP. This work supported by the Naval Research Laboratory Base Program.

Global Survey of Precipitation Properties Observed during Tropical Cyclogenesis and Their Differences Compared to Nondeveloping Disturbances

NASA Astrophysics Data System (ADS)

Zawislak, J.

2017-12-01

This study contributes to a global survey of the precipitation properties of developing and nondeveloping tropical disturbances, with a focus on distinguishing properties of those disturbances that develop into tropical cyclones (TCs) from those that do not develop. Precipitation properties are quantified using a unique accumulation of overpasses of pre-genesis TCs and nondeveloping disturbances from multiple satellite-borne passive microwave imagers. The overpasses are a subset of a broader Tropical Cyclone - Passive Microwave (TC-PMW) dataset that encompasses all stages of the TC life cycle. The TC-PMW consists of 14 years (2003-2016) of overpasses of pre-genesis and nondeveloping disturbances globally (the North Atlantic, East Pacific, Central Pacific, West Pacific, northern Indian Ocean, and Southern Hemisphere oceanic basins). Nondeveloping disturbances are defined as those disturbances that do not exceed an "invest" classification by the operational centers (NHC, CPHC, and JTWC). Overall, this study will offer a detailed analysis of the precipitation properties (i.e., areal coverage of rainfall and deep convection, depth, or intensity, of convection, proximity of precipitation to the center) multiple days before genesis. These analyses offer an opportunity to determine whether the properties of precipitation at, and just prior to, genesis are unique compared to previous days of the pre-genesis stage. By evaluating these properties over the robust sample provided by the TC-PMW dataset, results may lend support to the hypothesis that genesis is more closely tied to the fractional coverage of precipitation near the center rather than to any uniquely "intense" convection. The study will also investigate whether there are significant differences among the basins in the properties of precipitation involved in tropical cyclogenesis.

77 FR 47922 - BNSF Railway Company-Trackage Rights Exemption-Northern Lines Railway, Inc.

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-10

... includes: (a) Track 204 between 33rd Avenue North and Rice Junction, Minn.; and (b) Track 203 between milepost 0.0, at Rice Junction, and milepost 5.71, just west of the Highway I-94 overpass (the Lines). \\1...

MSE wall void repair effect on corrosion of reinforcement - phase 2 : specialty fill materials, [summary].

DOT National Transportation Integrated Search

2015-06-01

Ramps leading, for example, to overpasses or bridges are usually constructed using : mechanically stabilized earth (MSE) walls, earthworks retained by concrete walls. Because : MSE walls are reinforced with steel embedded in the fill, their fill is c...

Hurricane Isaac

Atmospheric Science Data Center

2014-05-15

... scale. At the time of the overpass, MISR recorded low-level wind speeds of up to 75 miles per hour (65 knots) from cloud motion observed ... moist air at low levels in the atmosphere, convert it into energy in the form of wind and rain, and then eject cool, dry air at high ...

Pavement/sub-grade condition assessment I-65 approximate milepost 97.5 (transition from asphalt) to 102.5 (KY 313 overpass).

DOT National Transportation Integrated Search

2005-06-01

In efforts to perform an assessment of both the existing pavement and the underlying subgrade conditions, the Kentucky Transportation Center employed the use of three types of equipment/infrastructure analyzers: drill truck for taking field cores; fa...

74. East elevation of elevated Mainline structure (Section F6) looking ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

74. East elevation of elevated Mainline structure (Section F-6) looking West - along the Arborway toward the masonry bridge carrying the former New Haven R.R. tracks over the Arborway. Arborway overpass is at upper right. - Boston Elevated Railway, Elevated Mainline, Washington Street, Boston, Suffolk County, MA

2. GRADIENT INTO A STREET IN SUPPLY CENTER, FROM SIDEWALK ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. GRADIENT INTO A STREET IN SUPPLY CENTER, FROM SIDEWALK ON SOUTHERN SIDE OF BRIDGE AT A POINT EAST OF 4TH STREET, LOOKING WEST, WITH MONUMENT AT END OF A STREET. - Oakland Naval Supply Center, Maritime Street Overpass, Connecting Seventh Street & Third Street, Oakland, Alameda County, CA

OVERVIEW OF BRIDGES WITH OR&L BRIDGE IN CENTER, WAIKELE CANAL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OVERVIEW OF BRIDGES WITH OR&L BRIDGE IN CENTER, WAIKELE CANAL BRIDGE IN BACKGROUND. SHOWING THE EARTHEN INCLINE THAT RAISES FARRINGTON HIGHWAY OVER THE FORMER OR&L TRACKS. VIEW FACING SOUTHWEST. - Waikele Canal Bridge and Highway Overpass, Farrington Highway and Waikele Stream, Waipahu, Honolulu County, HI

78 FR 55337 - Buy America Waiver Notification

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-10

... components for construction of Monon Trail Bridge over SR 25 in Indiana. DATES: The effective date of the... bridge components for construction of Monon Trail Bridge over SR 25 in Indiana. The Indiana Department of Transportation (INDOT) requested this waiver for an overpass to carry the Monon High Bridge Trail across the new...

The impact of acquisition times on the accuracy of microwave soil moisture retrievals over the contiguous U.S.

USDA-ARS?s Scientific Manuscript database

Satellite-derived soil moisture products have become an important data source for the study of land surface processes and related applications. For satellites with sun-synchronous orbits, these products are typically derived separately for ascending and descending overpasses with different local acq...

Long-Term Comparisons of OMI Surface UV Irradiances to a NILU_UV Multi-Filter Radiometer in Thessaloniki, Greece

NASA Astrophysics Data System (ADS)

Zempila, Melina Maria; Koukouli, Maria Elissavet; Bais, Alkiviadis; Arola, Antii; Fountoulakis, Ilias; Kouremeti, Natalia; Kazadzis, Stelios; Balis, Dimitrios

2016-08-01

The evaluation of the surface UV irradiances, derived from the Ozone Monitoring Instrument (OMI) onboard the AURA satellite, with those extracted from a Norwegian Institute for Air Research UV multi-filter actinometer (NILU-UV) situated in the Laboratory of Atmospheric Physics (LAP) in the Aristotle University of Thessaloniki (40.69°N, 22.96°E) is presented in this study.The NILU-UV data have been compared with the OMI/Aura overpass and local noon irradiances at 305, 310, 324 and 380 nm for a 10 year period over Thessaloniki between 2005 and 2014.The OMI irradiances were found to overestimate the NILU-UV observations in Thessaloniki between 4.5% and 13.5% for the 305nm wavelength and between 1.5% and 10.0% for the 310nm case. For the 324nm and 380nm, the satellite-deduced local-noon time comparisons showed a satellite under-estimation of 3.75% and 4.15% respectively whereas the overpass-time comparisons range between -1.55% and -1.90% for the same wavelengths.

Jaguar (Panthera onca Linnaeus, 1758) roadkill in Brazilian Atlantic Forest and implications for species conservation.

PubMed

Srbek-Araujo, A C; Mendes, S L; Chiarello, A G

2015-08-01

We report the roadkill of a jaguar in one of the longest highways in Brazil (BR-101), in the stretch where this road crosses one of the most important Atlantic Forest remnants in the country: the Linhares-Sooretama block. The jaguar population present in this area represents the very last in entire Espírito Santo state. There is an approved project to the lines duplication of the entire BR-101 Highway and the company responsible by the work has already started the first activities in the state. However, there is no environmental impact assessment already done neither planning for the implementation of measures to avoid or reduce the roadkill risk in the region. Thus, to minimize the impacts associated with the BR-101, we do not recommend its lines duplication along the 15 km stretch traversing the Linhares-Sooretama block. In addition, alternatively, we suggest the deviation of the current route of the BR-101 Highway or the construction of overpasses to fauna in the most critical points, interspersing these overpasses with electronic speed monitoring devices and warning and educational plates.

Preliminary evaluation of the airborne imaging spectrometer for vegetation analysis in the Klamath National Forest of northeastern California

NASA Technical Reports Server (NTRS)

Strahler, A. H.; Woodcock, C. E.; Avila, F. X.

1985-01-01

The experiences and results associated with a project entitled Preliminary Evaluation of the Airborne Imaging Spectrometer for Vegetation Analysis is documented. The primary goal of the project was to provide ground truth, manual interpretation, and computer processing of data from an experimental flight of the Airborne Infrared Spectrometer (AIS) to determine the extent to which high spectral resolution remote sensing could differentiate among plant species, and especially species of conifers, for a naturally vegetated test site. Through the course of the research, JPL acquired AIS imagery of the test areas in the Klamath National Forest, northeastern California, on two overflights of both the Dock Well and Grass Lake transects. Over the next year or so, three generations of data was also received: first overflight, second overflight, and reprocessed second overflight. Two field visits were made: one trip immediately following the first overflight to note snow conditions and temporally-related vegetation states at the time of the sensor overpass; and a second trip about six weeks later, following acquisition of prints of the images from the first AIS overpass.

Monitoring physical and chemical parameters of Delaware Bay waters with an ERTS-1 data collection platform

NASA Technical Reports Server (NTRS)

Klemas, V. (Principal Investigator); Wethe, C.

1975-01-01

The author has identified the following significant results. Results of the analysis of data collected during the summer of 1974 demonstrate that the ERTS Data Collection Platform (DCP) is quite responsive to changing water parameters and that this information can be successfully transmitted under all weather conditions. The monitoring of on-site probe outputs reveals a rapid response to changing water temperature, salinity, and turbidity conditions on incoming tides as the tidal salt wedge passes the probe location. The changes in water properties were corroborated by simultaneously sampling the water for subsequent laboratory analysis. Fluctuations observed in the values of salinity, conductivity, temperature and water depth over short time intervals were extremely small. Due to the nature of the probe, 10% to 20% fluctuations were observed in the turbidity values. The use of the average of the values observed during an overpass provided acceptable results. Good quality data was obtained from the satellite on each overpass regardless of weather conditions. Continued use of the DCP will help provide an indication of the accuracy of the probes and transmission system during long term use.

Evaluation and comparison of ERTS measurements of major crops and soil associations for selected sites in the central United States

NASA Technical Reports Server (NTRS)

Baumgardner, M. F. (Principal Investigator)

1973-01-01

The author has identified the following significant results. The most significant result was the use of the temporal overlay technique where the computer was used to overlay ERTS-1 data from three different dates (9 Oct., 14 Nov., 2 Dec.). The registration of MSS digital data from different dates was estimated to be accurate within one half resolution element. The temporal overlay capability provides a significant advance in machine-processing of MSS data. It is no longer essential to go through the tedious exercise of locating ground observation sites on the digital data from each ERTS-1 overpass. Once the address of a ground observation site has been located on a digital tape from any ERTS-1 overpass, the overlay technique can be used to locate the same address on a digital tape of MSS data from any other ERTS-1 pass over the same area. The temporal overlay technique also adds a valuable dimension for identifying and mapping changes in vegetation, water, and other dynamic surface features.

The Relationship of Temporal Variations in SMAP Vegetation Optical Depth to Plant Hydraulic Behavior

NASA Astrophysics Data System (ADS)

Konings, A. G.

2016-12-01

The soil emissions measured by L-band radiometers such as that on the NASA Soil Moisture Active/Passive mission are modulated by vegetation cover as quantified by the soil scattering albedo and the vegetation optical depth (VOD). The VOD is linearly proportional to the total vegetation water content, which is dependent on both the biomass and relative water content of the plant. Biomass is expected to vary more slowly than water content. Variations in vegetation water content are highly informative as they are directly indicative of the degree of hydraulic stress (or lack thereof) experienced by the plant. However, robust retrievals are needed in order for SMAP VOD observations to be useful. This is complicated by the fact that multiple unknowns (soil moisture, VOD, and albedo) need to be determined from two highly correlated polarizations. This presentation will discuss the application to SMAP of a recently developed timeseries algorithm for VOD and albedo retrieval - the Multi-Temporal Dual Channel Algorithm MTDCA, and its interpretation for plant hydraulic applications. The MT-DCA is based on the assumption that, for consecutive overpasses at a given time of day, VOD varies more slowly than soil moisture. A two-overpass moving average can then be used to determine variations in VOD that are less sensitive to high-frequency noise than classical dual-channel algorithms. Seasonal variations of SMAP VOD are presented and compared to expected patterns based on rainfall and radiation seasonality. Taking advantage of the large diurnal variation (relative to the seasonal variation) of canopy water potention, diurnal variations (between 6AM and 6PM observations) of SMAP VOD are then used to calculate global variations in ecosystem-scale isohydricity - the degree of stomatal closure and xylem conductivity loss in response to water stress. Lastly, the effect of satellite sensing frequency and overpass time on water content across canopies of different height will be discussed.

Cross-calibration of the Oceansat-2 Ocean Colour Monitor (OCM) with Terra and Aqua MODIS

NASA Astrophysics Data System (ADS)

Angal, Amit; Brinkmann, Jake; Kumar, A. Senthil; Xiong, Xiaoxiong

2016-05-01

The Ocean Colour Monitor (OCM) sensor on-board the Oceansat-2 spacecraft has been operational since its launch in September, 2009. The Oceansat 2 OCM primary design goal is to provide continuity to Oceansat-1 OCM to obtain information regarding various ocean-colour variables. OCM acquires Earth scene measurements in eight multi-spectral bands in the range from 402 to 885 nm. The MODIS sensor on the Terra and Aqua spacecraft has been successfully operating for over a decade collecting measurements of the earth's land, ocean surface and atmosphere. The MODIS spectral bands, designed for land and ocean applications, cover the spectral range from 412 to 869 nm. This study focuses on comparing the radiometric calibration stability of OCM using near-simultaneous TOA measurements with Terra and Aqua MODIS acquired over the Libya 4 target. Same-day scene-pairs from all three sensors (OCM, Terra and Aqua MODIS) between August, 2014 and September, 2015 were chosen for this analysis. On a given day, the OCM overpass is approximately an hour after the Terra overpass and an hour before the Aqua overpass. Due to the orbital differences between Terra and Aqua, MODIS images the Libya 4 site at different scan-angles on a given day. Some of the high-gain ocean bands for MODIS tend to saturate while viewing the bright Libya 4 target, but bands 8-10 (412 nm - 486 nm) provide an unsaturated response and are used for comparison with the spectrally similar OCM bands. All the standard corrections such as bidirectional reflectance factor (BRDF), relative spectral response mismatch, and impact for atmospheric water-vapor are applied to obtain the reflectance differences between OCM and the two MODIS instruments. Furthermore, OCM is used as a transfer radiometer to obtain the calibration differences between Terra and Aqua MODIS reflective solar bands.

Cross-Calibration of the Oceansat-2 Ocean Colour Monitor (OCM) with Terra and Aqua MODIS

NASA Technical Reports Server (NTRS)

Angal, Amit; Brinkmann, Jake; Kumar, A. Senthil; Xiong, Xiaoxiong

2016-01-01

The Ocean Colour Monitor (OCM) sensor on-board the Oceansat-2 spacecraft has been operational since its launch in September, 2009. The Oceansat 2 OCM primary design goal is to provide continuity to Oceansat-1 OCM to obtain information regarding various ocean-colour variables. OCM acquires Earth scene measurements in eight multi-spectral bands in the range from 402 to 885 nm. The MODIS sensor on the Terra and Aqua spacecraft has been successfully operating for over a decade collecting measurements of the earth's land, ocean surface and atmosphere. The MODIS spectral bands, designed for land and ocean applications, cover the spectral range from 412 to 869 nm. This study focuses on comparing the radiometric calibration stability of OCM using near-simultaneous TOA measurements with Terra and Aqua MODIS acquired over the Libya 4 target. Same-day scene-pairs from all three sensors (OCM, Terra and Aqua MODIS) between August, 2014 and September, 2015 were chosen for this analysis. On a given day, the OCM overpass is approximately an hour after the Terra overpass and an hour before the Aqua overpass. Due to the orbital differences between Terra and Aqua, MODIS images the Libya 4 site at different scan-angles on a given day. Some of the high-gain ocean bands for MODIS tend to saturate while viewing the bright Libya 4 target, but bands 8-10 (412 nm - 486 nm) provide an unsaturated response and are used for comparison with the spectrally similar OCM bands. All the standard corrections such as bidirectional reflectance factor (BRDF), relative spectral response mismatch, and impact for atmospheric water-vapor are applied to obtain the reflectance differences between OCM and the two MODIS instruments. Furthermore, OCM is used as a transfer radiometer to obtain the calibration differences between Terra and Aqua MODIS reflective solar bands.

OVERVIEW OF BRIDGES WITH WAIKELE CANAL BRIDGE IN CENTER, OR&L ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OVERVIEW OF BRIDGES WITH WAIKELE CANAL BRIDGE IN CENTER, OR&L BRIDGE IN BACKGROUND. SHOWING THE EARTHEN INCLINE THAT RAISES FARRINGTON HIGHWAY OVER THE FORMER OR&L TRACKS. NOTE THE 1963 WESTBOUND BRIDGE IN THE FOREGROUND. VIEW FACING EAST. - Waikele Canal Bridge and Highway Overpass, Farrington Highway and Waikele Stream, Waipahu, Honolulu County, HI

OBLIQUE VIEW SHOING THE OR&L BRIDGE IN THE FOREGROUND. NOTE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OBLIQUE VIEW SHOING THE OR&L BRIDGE IN THE FOREGROUND. NOTE THE ARC-PLAN END STACHION AND THE RELATIONSHIP BETWEEN THE OR&L BRIDGE AND THE WAIKELE CANAL BRIDGE, WHICH CAN BE SEEN IN THE BACKGROUND. VIEW FACING WEST. - Waikele Canal Bridge and Highway Overpass, Farrington Highway and Waikele Stream, Waipahu, Honolulu County, HI

23 CFR Appendix to Subpart B of... - Horizontal and Vertical Clearance Provisions for Overpass and Underpass Structures

Code of Federal Regulations, 2010 CFR

2010-04-01

... maintenance road or by evidence of future need for such equipment. All piers should be placed at least 2.8... up to 2.5 meters as may be necessary for off-track maintenance equipment, provided adequate... road crossings for this purpose. Where not feasible, an additional structure width of 2.5 meters may be...

Evaluating multiple causes of persistent low microwave backscatter from Amazon forests after the 2005 drought

Treesearch

Steve Frolking; Stephen Hagen; Bobby Braswell; Tom Milliman; Christina Herrick; Seth Peterson; Dar Roberts; Michael Keller; Michael Palace; Krishna Prasad Vadrevu

2017-01-01

Amazonia has experienced large-scale regional droughts that affect forest productivity and biomass stocks. Space-borne remote sensing provides basin-wide data on impacts of meteorological anomalies, an important complement to relatively limited ground observations across the Amazon’s vast and remote humid tropical forests. Morning overpass QuikScat Ku-band microwave...

Reassessment of the temperature-emissivity separation from multispectral thermal infrared data: Introducing the impact of vegetation canopy by simulating the cavity effect with the SAIL-Thermique model

USDA-ARS?s Scientific Manuscript database

We investigated the use of multispectral thermal imagery to retrieve land surface emissivity and temperature. Conversely to concurrent methods, the temperature emissivity separation (TES) method simply requires single overpass without any ancillary information. This is possible since TES makes use o...

Application of ERTS-1-data to the protection and management of New Jersey's coastal environment

NASA Technical Reports Server (NTRS)

Yunghans, R. S.; Feinberg, E. B.; Mairs, R. L. (Principal Investigator); Woodward, D.; Thibault, D. A.; Macomber, R. T.

1973-01-01

The author has identified the following significant results. New Jersey's planned, regionalized network of sewage disposal facilities has been plotted on an ERTS-1 mosaic and circulation parameters for each of the planned outfall locations have been analyzed using the ERTS-1 imagery and comparative aircraft photography. Work is continuing on the circulation and dispersion of barge-dumped wastes in the New York Bight area. One of the largest remote sensing experiments ever attempted in this country was completed on April 7, 1973 during the ERTS-1 overpass. The test area included the northern portion of New Jersey and the Raritan Bay - New York Harbor area. Three NASA aircraft, two helicopters, nine surface vessels, 40 ground team personnel, and numerous oceanographic, radiometric, and meteorological equipment were deployed in an effort to characterize the surface and near-surface circulation dynamics in this 600 square mile area, during an entire tidal cycle. The analyses of these data in concert with all previous ERTS-1 overpasses will provide information that can lead to a better and more rational use of the nearshore marine environment. The data will be utilized to plan future outfall locations, regulating offshore disposal of wastes, etc.

MaROS: Web Visualization of Mars Orbiting and Landed Assets

NASA Technical Reports Server (NTRS)

Wallick, Michael N.; Allard, Daniel A.; Gladden, Roy E.; Hy, Franklin H.

2011-01-01

Mars Relay operations currently involve several e-mails and phone calls between lander and orbiter teams in order to settle on an agreed time for performing a communication pass between the landed asset (i.e. rover or lander) and orbiter, then back to Earth. This new application aims to reduce this complexity by presenting a visualization of the overpass time ranges and elevation angle, as well as other information. The user is able to select a specific overflight opportunity to receive further information about that particular pass. This software presents a unified view of the potential communication passes available between orbiting and landed assets on Mars. Each asset is presented to the user in a graphical view showing overpass opportunities, elevation angle, requested and acknowledged communication windows, forward and back latencies, warnings, conflicts, relative planetary times, ACE Schedules, and DSN information. This software is unique in that it is the first of its kind to visually display the information regarding communication opportunities between landed and orbiting Mars assets. The software is written using ActionScript/FLEX, a Web language, meaning that this information may be accessed over the Internet from anywhere in the world.

Multipurpose Spectroradiometer for Satellite Instrument Calibration and Zenith Sky Remote Sensing Measurements

NASA Technical Reports Server (NTRS)

Heath, Donald F.; Ahmad, Zia

2001-01-01

In the early 1990s a series of surface-based direct sun and zenith sky measurements of total column ozone were made with SBUV/2 flight models and the SSBUV Space Shuttle instrument in Boulder, Colorado which were compared with NOAA Dobson Instrument direct sun observations and TOMS instrument overpass observations of column ozone. These early measurements led to the investigation of the accuracy of derived total column ozone amounts and aerosol optical depths from zenith sky observations. Following the development and availability of radiometrically stable IAD narrow band interference filter and nitrided silicon photodiodes a simple compact multifilter spectroradiometer was developed which can be used as a calibration transfer standard spectroradiometer (CTSS) or as a surface based instrument remote sensing instruments for measurements of total column ozone and aerosol optical depths. The total column ozone derived from zenith sky observations agrees with Dobson direct sun AD double wavelength pair measurements and with TOMS overpass ozone amounts within uncertainties of about 1%. When used as a calibration transfer standard spectroradiometer the multifilter spectroradiometer appears to be capable of establishing instrument radiometric calibration uncertainties of the order of 1% or less relative to national standards laboratory radiometric standards.

Understanding intersatellite biases of microwave humidity sounders using global simultaneous nadir overpasses

NASA Astrophysics Data System (ADS)

John, Viju O.; Holl, Gerrit; Buehler, Stefan A.; Candy, Brett; Saunders, Roger W.; Parker, David E.

2012-01-01

Simultaneous nadir overpasses (SNOs) of polar-orbiting satellites are most frequent in polar areas but can occur at any latitude when the equatorial crossing times of the satellites become close owing to orbital drift. We use global SNOs of polar orbiting satellites to evaluate the intercalibration of microwave humidity sounders from the more frequent high-latitude SNOs. We have found based on sensitivity analyses that optimal distance and time thresholds for defining collocations are pixel centers less than 5 km apart and time differences less than 300 s. These stringent collocation criteria reduce the impact of highly variable surface or atmospheric conditions on the estimated biases. Uncertainties in the estimated biases are dominated by the combined radiometric noise of the instrument pair. The effects of frequency changes between different versions of the humidity sounders depend on the amount of water vapor in the atmosphere. There are significant scene radiance and thus latitude dependencies in the estimated biases and this has to taken into account while intercalibrating microwave humidity sounders. Therefore the results obtained using polar SNOs will not be representative for moist regions, necessitating the use of global collocations for reliable intercalibration.

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.

Ground-Based Lidar Measurements During the CALIPSO and Twilight Zone (CATZ) Campaign

NASA Technical Reports Server (NTRS)

Berkoff, Timothy; Qian, Li; Kleidman, Richard; Stewart, Sebastian; Welton, Ellsworth; Li, Zhu; Holbem, Brent

2008-01-01

The CALIPSO and Twilight Zone (CATZ) field campaign was carried out between June 26th and August 29th of 2007 in the multi-state Maryland-Virginia-Pennsylvania region of the U.S. to study aerosol properties and cloud-aerosol interactions during overpasses of the CALIPSO satellite. Field work was conducted on selected days when CALIPSO ground tracks occurred in the region. Ground-based measurements included data from multiple Cimel sunphotometers that were placed at intervals along a segment of the CALIPSO ground-track. These measurements provided sky radiance and AOD measurements to enable joints inversions and comparisons with CALIPSO retrievals. As part of this activity, four ground-based lidars provided backscatter measurements (at 523 nm) in the region. Lidars at University of Maryland Baltimore County (Catonsville, MD) and Goddard Space Flight Center (Greenbelt, MD) provided continuous data during the campaign, while two micro-pulse lidar (MPL) systems were temporarily stationed at various field locations directly on CALIPSO ground-tracks. As a result, thirteen on-track ground-based lidar observations were obtained from eight different locations in the region. In some cases, nighttime CALIPSO coincident measurements were also obtained. In most studies reported to date, ground-based lidar validation efforts for CALIPSO rely on systems that are at fixed locations some distance away from the satellite ground-track. The CATZ ground-based lidar data provide an opportunity to examine vertical structure properties of aerosols and clouds both on and off-track simultaneously during a CALIPSO overpass. A table of available ground-based lidar measurements during this campaign will be presented, along with example backscatter imagery for a number of coincident cases with CALIPSO. Results indicate that even for a ground-based measurements directly on-track, comparisons can still pose a challenge due to the differing spatio-temporal properties of the ground and satellite observations. The multiple-lidar data during the CATZ campaign is expected to provide additional information on regional aerosol and cloud dynamics for give overpass, and enable a more realistic assessment of ground-to-satellite correlations. Future work is anticipated to finalize calibrated lidar backscatter profiles and utilization of wind trajectory information to further enable comparisons to CALIPS data.

Vicarious Calibration of sUAS Microbolometer Temperature Imagery for Estimation of Radiometric Land Surface Temperature.

PubMed

Torres-Rua, Alfonso

2017-06-26

In recent years, the availability of lightweight microbolometer thermal cameras compatible with small unmanned aerial systems (sUAS) has allowed their use in diverse scientific and management activities that require sub-meter pixel resolution. Nevertheless, as with sensors already used in temperature remote sensing (e.g., Landsat satellites), a radiance atmospheric correction is necessary to estimate land surface temperature. This is because atmospheric conditions at any sUAS flight elevation will have an adverse impact on the image accuracy, derived calculations, and study replicability using the microbolometer technology. This study presents a vicarious calibration methodology (sUAS-specific, time-specific, flight-specific, and sensor-specific) for sUAS temperature imagery traceable back to NIST-standards and current atmospheric correction methods. For this methodology, a three-year data collection campaign with a sUAS called "AggieAir", developed at Utah State University, was performed for vineyards near Lodi, California, for flights conducted at different times (early morning, Landsat overpass, and mid-afternoon") and seasonal conditions. From the results of this study, it was found that, despite the spectral response of microbolometer cameras (7.0 to 14.0 μm), it was possible to account for the effects of atmospheric and sUAS operational conditions, regardless of time and weather, to acquire accurate surface temperature data. In addition, it was found that the main atmospheric correction parameters (transmissivity and atmospheric radiance) significantly varied over the course of a day. These parameters fluctuated the most in early morning and partially stabilized in Landsat overpass and in mid-afternoon times. In terms of accuracy, estimated atmospheric correction parameters presented adequate statistics (confidence bounds under ±0.1 for transmissivity and ±1.2 W/m²/sr/um for atmospheric radiance, with a range of RMSE below 1.0 W/m²/sr/um) for all sUAS flights. Differences in estimated temperatures between original thermal image and the vicarious calibration procedure reported here were estimated from -5 °C to 10 °C for early morning, and from 0 to 20 °C for Landsat overpass and mid-afternoon times.

Vicarious Calibration of sUAS Microbolometer Temperature Imagery for Estimation of Radiometric Land Surface Temperature

PubMed Central

2017-01-01

In recent years, the availability of lightweight microbolometer thermal cameras compatible with small unmanned aerial systems (sUAS) has allowed their use in diverse scientific and management activities that require sub-meter pixel resolution. Nevertheless, as with sensors already used in temperature remote sensing (e.g., Landsat satellites), a radiance atmospheric correction is necessary to estimate land surface temperature. This is because atmospheric conditions at any sUAS flight elevation will have an adverse impact on the image accuracy, derived calculations, and study replicability using the microbolometer technology. This study presents a vicarious calibration methodology (sUAS-specific, time-specific, flight-specific, and sensor-specific) for sUAS temperature imagery traceable back to NIST-standards and current atmospheric correction methods. For this methodology, a three-year data collection campaign with a sUAS called “AggieAir”, developed at Utah State University, was performed for vineyards near Lodi, California, for flights conducted at different times (early morning, Landsat overpass, and mid-afternoon”) and seasonal conditions. From the results of this study, it was found that, despite the spectral response of microbolometer cameras (7.0 to 14.0 μm), it was possible to account for the effects of atmospheric and sUAS operational conditions, regardless of time and weather, to acquire accurate surface temperature data. In addition, it was found that the main atmospheric correction parameters (transmissivity and atmospheric radiance) significantly varied over the course of a day. These parameters fluctuated the most in early morning and partially stabilized in Landsat overpass and in mid-afternoon times. In terms of accuracy, estimated atmospheric correction parameters presented adequate statistics (confidence bounds under ±0.1 for transmissivity and ±1.2 W/m2/sr/um for atmospheric radiance, with a range of RMSE below 1.0 W/m2/sr/um) for all sUAS flights. Differences in estimated temperatures between original thermal image and the vicarious calibration procedure reported here were estimated from −5 °C to 10 °C for early morning, and from 0 to 20 °C for Landsat overpass and mid-afternoon times. PMID:28672864

Relationships between Electrical and Radar Characteristics of Thunderstorms Observed During ACES

NASA Technical Reports Server (NTRS)

Buechler, Dennis E.; Mach, Douglas M.; Blakeslee, Richard J.

2003-01-01

The Altus Cumulus Electrification Study (ACES) took place near Key West, Florida during August 2002. A high altitude, remotely piloted aircraft obtained optical pulse and electric field data over a number of thunderstorms during the study period. Measurements of the vertical electric field and cross sections of radar reflectivity along the flight track are shown for 2 overpasses of a thunderstorm that occurred on 10 August 2002.

JPRS Report, East Europe.

DTIC Science & Technology

1990-01-24

surfacing, the loadbearing capacity and dimensions of differences in height above sea level. Tablets or steel of bridges and overpasses, ammunition depots...here," says Lucjan Szafran- ests, names of localities and hamlets, and the adminis- ski, a master operator of offset presses. "A bridge must trative...still provisionally shaped in West Germany , and that CSSR factories are quite by the nomenclatura’s candidates, as he puts it. competitive in

Results from two years of ozone data taken with a new, ground-based microwave instrument: An overview

NASA Technical Reports Server (NTRS)

Parrish, A.; Connor, B. J.; Tsou, J. J.; Mcdermid, I. S.; Chu, W. P.; Siskind, D. E.

1994-01-01

An overview of two years of data obtained with a ground-based microwave instrument is given. Intercomparisons with data obtained by the co-located JPL lidar and by SAGE 2 during near overpasses of the site are discussed, as are comparisons with mesospheric data taken earlier by SME and LIMS. Observations of diurnal variations of mesospheric ozone are shown.

Application of LANDSAT-2 to the management of Delaware's marine and wetland resources

NASA Technical Reports Server (NTRS)

Klemas, V. (Principal Investigator); Bartlett, D.; Philpot, W.; Davis, G.

1977-01-01

The author has identified the following significant results. The problem of remote sensing of suspended matter in water was analyzed in terms of the single scattering albedo, and a semiempirical relationship between satellite radiance measurements and the concentration of suspended matter in the water was developed. The relationship was tested using data from the 7 July 1973 LANDSAT overpass of Delaware Bay with good results.

Final Environmental Assessment for the First Air Force Air Operations Center, First Air Force Headquarters/Air Force Forces Center, and Highway 98 Overpass at Tyndall Air Force Base, Florida

DTIC Science & Technology

2004-01-01

to contact Sandra Veazey at (850) 595-8300 for additional information on asbestos issues. The Florida Department of Transportation (FDOT) supports...The notification form for the Department can be found at the following web address:. The Air Force is advised to contact Sandra Veazey at (850) 595

Monitoring the dispersion of ocean waste disposal plumes from ERTS-1 and Skylab. [Delaware coastal waters

NASA Technical Reports Server (NTRS)

Klemas, V. (Principal Investigator); Davis, G.; Myers, T.

1974-01-01

The author has identified the following significant results. About forty miles off the Delaware coast is located the disposal site for waste discharged from a plant processing titanium dioxide. The discharge is a greenish-brown; 15-20% acid liquid which consists primarily of iron chlorides and sulfates. The barge which transports this waste has a 1,000,000 gallon capacity and makes approximately three trips to the disposal site per week. ERTS-1 MSS digital tapes are being used to study the dispersion patterns and drift velocities of the iron-acid plume. Careful examination of ERTS-1 imagery disclosed a fishhook-shaped plume about 40 miles east of Cape Henlopen caused by a barge disposing acid wastes. The plume shows up more strongly in the green band than in the red band. Since some acids have a strong green component during dumping and turn slowly more brownish-reddish with age, the ratio of radiance signatures between the green and red bands may give an indication of how long before the satellite overpass the acid was dumped. Enlarged enhancements of the acid waste plumes, prepared from the ERTS-1 MSS digital tapes aided considerably in studies of the dispersion of the waste plume. Currently acid dumps are being coordinated with ERTS-1 overpasses.

The 27-28 October 1986 FIRE Cirrus case study - Retrieval of cloud particle sizes and optical depths from comparative analyses of aircraft and satellite-based infrared measurements

NASA Technical Reports Server (NTRS)

Hammer, Philip D.; Valero, Francisco P. J.; Kinne, Stefan

1991-01-01

Infrared radiance measurements were acquired from a narrow-field nadir-viewing radiometer based on the NASA ER-2 aircraft during a coincident Landsat 5 overpass on October 28, 1986 as part of the FIRE Cirrus IFO in the vicinity of Lake Michigan. The spectral bandpasses are 9.90-10.87 microns for the ER-2-based radiometer and 10.40-12.50 microns for the Landsat thematic mapper band. After adjusting for spatial and temporal differences, a comparative study using data from these two instruments is undertaken in order to retrieve cirrus cloud ice-crystal sizes and optical depths. Retrieval is achieved by analysis of measurement correlations between the two spectral bands and comparison to multistream radiative transfer model calculations. The results indicate that the equivalent sphere radii of the cirrus ice crystals were typically less than 30 microns. Such particles were too small to be measured by the available in situ instrumentation. Cloud optical depths at a reference wavelength of 11.4 microns ranged from 0.3 to 2.0 for this case study. Supplemental results in support of this study are described using radiation measurements from the King Air aircraft, which was also in near coincidence with the Landsat overpass.

Spaceborne Microwave Remote Sensing of Seasonal Freeze-Thaw Processes in the Terrestrial High Latitudes: Relationships with Land-Atmosphere CO2 exchange

NASA Technical Reports Server (NTRS)

McDonald, Kyle C.; Kimball, John S.; Zhao, Maosheng; Njoku, Eni; Zimmermann, Reiner; Running, Steven W.

2004-01-01

Landscape transitions between seasonally frozen and thawed conditions occur each year over roughly 50 million square kilometers of Earth's Northern Hemisphere. These relatively abrupt transitions represent the closest analog to a biospheric and hydrologic on/off switch existing in nature, affecting surface meteorological conditions, ecological trace gas dynamics, energy exchange and hydrologic activity profoundly. We utilize time series satellite-borne microwave remote sensing measurements from the Special Sensor Microwave Imager (SSM/I) to examine spatial and temporal variability in seasonal freeze/thaw cycles for the pan-Arctic basin and Alaska. Regional measurements of spring thaw timing are derived using daily brightness temperature measurements from the 19 GHz, horizontally polarized channel, separately for overpasses with 6 AM and 6 PM equatorial crossing times. Spatial and temporal patterns in regional freeze/thaw dynamics show distinct differences between North America and Eurasia, and boreal forest and Arctic tundra biomes. Annual anomalies in the timing of thawing in spring also correspond closely to seasonal atmospheric CO2 concentration anomalies derived from NOAA CMDL arctic and subarctic monitoring stations. Classification differences between AM and PM overpass data average approximately 5 days for the region, though both appear to be effective surrogates for monitoring annual growing seasons at high latitudes.

Spaceborne microwave remote sensing of seasonal freeze-thaw processes in theterrestrial high l atitudes : relationships with land-atmosphere CO2 exchange

NASA Technical Reports Server (NTRS)

McDonald, Kyle C.; Kimball, John S.; Zhao, Maosheng; Njoku, Eni; Zimmermann, Reiner; Running, Steven W.

2004-01-01

Landscape transitions between seasonally frozen and thawed conditions occur each year over roughly 50 million square kilometers of Earth's Northern Hemisphere. These relatively abrupt transitions represent the closest analog to a biospheric and hydrologic on/off switch existing in nature, affecting surface meteorological conditions, ecological trace gas dynamics, energy exchange and hydrologic activity profoundly. We utilize time series satellite-borne microwave remote sensing measurements from the Special Sensor Microwave Imager (SSM/I) to examine spatial and temporal variability in seasonal freeze/thaw cycles for the pan-Arctic basin and Alaska. Regional measurements of spring thaw timing are derived using daily brightness temperature measurements from the 19 GHz, horizontally polarized channel, separately for overpasses with 6 AM and 6 PM equatorial crossing times. Spatial and temporal patterns in regional freeze/thaw dynamics show distinct differences between North America and Eurasia, and boreal forest and Arctic tundra biomes. Annual anomalies in the timing of thawing in spring also correspond closely to seasonal atmospheric CO2 concentration anomalies derived from NOAA CMDL arctic and subarctic monitoring stations. Classification differences between AM and PM overpass data average approximately 5 days for the region, though both appear to be effective surrogates for monitoring annual growing seasons at high latitudes.

Can MODIS detect trends in aerosol optical depth over land?

NASA Astrophysics Data System (ADS)

Fan, Xuehua; Xia, Xiang'ao; Chen, Hongbin

2018-02-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard NASA's Aqua satellite has been collecting valuable data about the Earth system for more than 14 years, and one of the benefits of this is that it has made it possible to detect the long-term variation in aerosol loading across the globe. However, the long-term aerosol optical depth (AOD) trends derived from MODIS need careful validation and assessment, especially over land. Using AOD products with at least 70 months' worth of measurements collected during 2002-15 at 53 Aerosol Robotic Network (AERONET) sites over land, Mann-Kendall (MK) trends in AOD were derived and taken as the ground truth data for evaluating the corresponding results from MODIS onboard Aqua. The results showed that the AERONET AOD trends over all sites in Europe and North America, as well as most sites in Africa and Asia, can be reproduced by MODIS/Aqua. However, disagreement in AOD trends between MODIS and AERONET was found at a few sites in Australia and South America. The AOD trends calculated from AERONET instantaneous data at the MODIS overpass times were consistent with those from AERONET daily data, which suggests that the AOD trends derived from satellite measurements of 1-2 overpasses may be representative of those from daily measurements.

The Sentinel-2 MSI Can Increase the Temporal Resolution of 30m Satellite-Derived LAI Estimates

NASA Astrophysics Data System (ADS)

Dungan, J. L.; Li, S.; Ganguly, S.; Wang, W.; Nemani, R. R.; Ju, J.; Claverie, M.; Masek, J. G.

2016-12-01

The successful launch of the European Space Agency (ESA) Sentinel-2A (S2-A) on 23 June 2015 with its MultiSpectral Instrument (MSI) provides an important means to augment Earth-observation capabilities following the legacy of Landsat. After the three-month satellite commissioning campaign, the MSI onboard S-2A is performing very well (ESA, 2015). By 3 December 2015, the sensor data records have achieved provisional maturity status and have been accessed in level-1C Top-Of-Atmosphere (TOA) reflectance by the remote sensing community worldwide. Near-nadir observations by the MSI onboard S-2A and the Operational Land Imager (OLI) onboard Landsat 8 were collected during Simultaneous Nadir Overpasses as well as nearly coincident overpasses. This paper presents a processing chain using harmonized S-2A MSI and Landsat 8 OLI sensors to obtain increased temporal resolution in Leaf Area Index (LAI) estimates using the red-edge band B8A of MSI to replace the NIR band B08. Results demonstrate that LAI estimates from the MSI and OLI are comparable, and, given sufficient preprocessing for atmospheric correction and geometric rectification, can be used interchangeably to improve the frequency with which low LAI canopies can be monitored.

Meteorological and associated data collected over agricultural fields in Pinal County, Arizona, 1989 and 1990

USGS Publications Warehouse

Owen-Joyce, Sandra J.; Brown, Paul W.

1995-01-01

Data were collected at temporary meteorological stations installed in agricultural fields in Pinal County, Arizona, to evaluate the spatial and temporal variability of point data and to examine how station location affects ground-based meteorological data and the resulting values of evapotranspiration calculated using remotely sensed multispectral data from satellites. Time-specific data were collected to correspond with satellite overpasses from April to October 1989, and June 27-28, 1990. Meteorological data consisting of air temperature, relative humidity, wind speed, solar radiation, and net radiation were collected at each station during all periods of the project. Supplementary measurements of soil temperature, soil heat flux density, and surface or canopy temperature were obtained at some locations during certain periods of the project. Additional data include information on data-collection periods, station positions, instrumentation, sensor heights, and field dimensions. Other data, which correspond to the extensive field measurements made in con- junction with satellite overpasses in 1989 and 1990, include crop type, canopy cover, canopy height, irrigation, cultivation, and orientation of rows. Field boundaries and crop types were mapped in a 2- to 3-square-kilometer area surrounding each meteorological station. Field data are presented in tabular and graphic form. Meteorological and supplementary data are available, upon request, in digital form.

Movements of the First Satellite-Tagged Cuvier’s and Blainville’s Beaked Whales in Hawaii

DTIC Science & Technology

2008-10-06

satellite tagging 6 Data acquisition and processing PTT transmissions are received by a series of NOAA Polar Orbiting Environmental Satellites... polar orbiting path of the satellites means that there are fewer overpasses as you get closer to the equator. In Hawai‘i in 2008 for example, the...between consecutive locations, and rate and bearings among consecutive movement vectors). The Douglas filter incorporates several user-defined variables

Finding of No Significant Impact: First Air Force Air Operations Center, First Air Force Headquarters/Air Force Forces Center, and Highway 98 Overpass at Tyndall Air Force Base, Florida

DTIC Science & Technology

2004-11-10

found at the following web address: <http://dep.state.fl.us/air/forms/asbestos.htm#asbestos>. The Air Force is advised to contact Sandra Veazey at...advised to contact Sandra Veazey at (850) 595·8300 for additional information on asbestos issues. http://tlhora6.dep.state.fl.us/clearinghouse/agency

First Responders Immersive Training Simulation Environment (FRITSE): Scenario Development and Support

DTIC Science & Technology

2014-07-30

consisted of three stages: a deliberate derailment of a train containing either methanol (flammable) or ammonia (caustic) cars at an overpass where...event would be the deliberate release of chemical agent from a van parked near the train derailment and the tertiary event would be a giant fertilizer ...political targets is highest. The derailment would cause a major leak of either caustic ( ammonia ) or highly flammable (methanol) material from derailed

Machine Learning Algorithms for Automated Satellite Snow and Sea Ice Detection

NASA Astrophysics Data System (ADS)

Bonev, George

The continuous mapping of snow and ice cover, particularly in the arctic and poles, are critical to understanding the earth and atmospheric science. Much of the world's sea ice and snow covers the most inhospitable places, making measurements from satellite-based remote sensors essential. Despite the wealth of data from these instruments many challenges remain. For instance, remote sensing instruments reside on-board different satellites and observe the earth at different portions of the electromagnetic spectrum with different spatial footprints. Integrating and fusing this information to make estimates of the surface is a subject of active research. In response to these challenges, this dissertation will present two algorithms that utilize methods from statistics and machine learning, with the goal of improving on the quality and accuracy of current snow and sea ice detection products. The first algorithm aims at implementing snow detection using optical/infrared instrument data. The novelty in this approach is that the classifier is trained using ground station measurements of snow depth that are collocated with the reflectance observed at the satellite. Several classification methods are compared using this training data to identify the one yielding the highest accuracy and optimal space/time complexity. The algorithm is then evaluated against the current operational NASA snow product and it is found that it produces comparable and in some cases superior accuracy results. The second algorithm presents a fully automated approach to sea ice detection that integrates data obtained from passive microwave and optical/infrared satellite instruments. For a particular region of interest the algorithm generates sea ice maps of each individual satellite overpass and then aggregates them to a daily composite level, maximizing the amount of high resolution information available. The algorithm is evaluated at both, the individual satellite overpass level, and at the daily composite level. Results show that at the single overpass level for clear-sky regions, the developed multi-sensor algorithm performs with accuracy similar to that of the optical/infrared products, with the advantage of being able to also classify partially cloud-obscured regions with the help of passive microwave data. At the daily composite level, results show that the algorithm's performance with respect to total ice extent is in line with other daily products, with the novelty of being fully automated and having higher resolution.

Chapter A. The Loma Prieta, California, Earthquake of October 17, 1989 - Strong Ground Motion

USGS Publications Warehouse

Borcherdt, Roger D.

1994-01-01

Strong ground motion generated by the Loma Prieta, Calif., earthquake (MS~7.1) of October 17, 1989, resulted in at least 63 deaths, more than 3,757 injuries, and damage estimated to exceed $5.9 billion. Strong ground motion severely damaged critical lifelines (freeway overpasses, bridges, and pipelines), caused severe damage to poorly constructed buildings, and induced a significant number of ground failures associated with liquefaction and landsliding. It also caused a significant proportion of the damage and loss of life at distances as far as 100 km from the epicenter. Consequently, understanding the characteristics of the strong ground motion associated with the earthquake is fundamental to understanding the earthquake's devastating impact on society. The papers assembled in this chapter address this problem. Damage to vulnerable structures from the earthquake varied substantially with the distance from the causative fault and the type of underlying geologic deposits. Most of the damage and loss of life occurred in areas underlain by 'soft soil'. Quantifying these effects is important for understanding the tragic concentrations of damage in such areas as Santa Cruz and the Marina and Embarcadero Districts of San Francisco, and the failures of the San Francisco-Oakland Bay Bridge and the Interstate Highway 880 overpass. Most importantly, understanding these effects is a necessary prerequisite for improving mitigation measures for larger earthquakes likely to occur much closer to densely urbanized areas in the San Francisco Bay region. The earthquake generated an especially important data set for understanding variations in the severity of strong ground motion. Instrumental strong-motion recordings were obtained at 131 sites located from about 6 to 175 km from the rupture zone. This set of recordings, the largest yet collected for an event of this size, was obtained from sites on various geologic deposits, including a unique set on 'soft soil' deposits (artificial fill and bay mud). These exceptional ground-motion data are used by the authors of the papers in this chapter to infer radiation characteristics of the earthquake source, identify dominant propagation characteristics of the Earth?s crust, quantify amplification characteristics of near-surface geologic deposits, develop general amplification factors for site-dependent building-code provisions, and revise earthquake-hazard assessments for the San Francisco Bay region. Interpretations of additional data recorded in well-instrumented buildings, dams, and freeway overpasses are provided in other chapters of this report.

Midday values of gross CO2 flux and light use efficiency during satellite overpasses can be used to directly estimate eight-day mean flux

Treesearch

Daniel A. Sims; Abdullah F. Rahman; Vicente D. Cordova; Dennis D. Baldocchi; Lawrence B. Flanagan; Allen H. Goldstein; David Y. Hollinger; Laurent Misson; Russell K. Monson; Hans P. Schmid; Steven C. Wofsy; Liukang Xu

2005-01-01

Most satellites provide, at best, a single daily snapshot of vegetation and, at worst, these snapshots may be separated by periods of many days when the ground was obscured by cloud cover. Since vegetation carbon exchange can be very dynamic on diurnal and day-to-day timescales, the limited temporal resolution of satellite data is a potential limitation in the use of...

Stratospheric Aerosol and Gas Experiments 1 and 2: Comparisons with ozonesondes

NASA Technical Reports Server (NTRS)

Veiga, Robert E.; Cunnold, Derek M.; Chu, William P.; McCormick, M. Patrick

1995-01-01

Ozone profiles measured by the Stratospheric Aerosol and Gas Experiments (SAGE) 1 and 2 are compared with ozonesonde profiles at 24 stations over the period extending from 1979 through 1991. Ozonesonde/satellite differences at 21 stations with SAGE 2 overpasses were computed down to 11.5 km in midlatitudes, to 15.5 km in the lower latitudes, and for nine stations with SAGE 1 overpasses down to 15.5 km. The set of individual satellite and ozonesonde profile comparisons most closely colocated in time and space shows mean absolute differences relative to the satellite measurement of 6 +/- 2% for SAGE 2 and 8 +/- 3% for SAGE 1. The ensemble of ozonesonde/satellite differences, when averaged over all altitudes, shows that for SAGE 2, 70% were less than 5%, whereas for SAGE 1, 50% were less than 5%. The best agreement occurred in the altitude region near the ozone density maximum where almost all the relative differences were less than 5%. Most of the statistically significant differences occurred below the ozone maximum down to the tropopause in the region of steepest ozone gradients and typically ranged between 0 and -20%. Correlations between ozone and aerosol extinction in the northern midlatitudes indicate that aerosols had no discernible impact on the ozonesonde/satellite differences and on the SAGE 2 ozone retrieval for the levels of extinction encountered in the lower stratosphere during 1984 to mid-1991.

NASA CYGNSS Ocean Wind Observations in the 2017 Atlantic Hurricane Season

NASA Astrophysics Data System (ADS)

Ruf, C. S.; Balasubramaniam, R.; Mayers, D.; McKague, D. S.

2017-12-01

The CYGNSS constellation of eight satellites was successfully launched on 15 December 2016 into a low inclination (tropical) Earth orbit to measure ocean surface wind speed in the inner core of tropical cyclones with better than 12 hour refresh rates. Each satellite carries a four-channel bi-static radar receiver that measures GPS signals scattered by the ocean, from which ocean surface roughness, near surface wind speed, and air-sea latent heat flux are estimated. The measurements are unique in several respects, most notably in their ability to penetrate through all levels of precipitation, made possible by the low frequency at which GPS operates, and in the frequent sampling of tropical cyclone intensification, made possible by the large number of satellites. Level 2 science data products have been developed for near surface (10 m referenced) ocean wind speed, ocean surface roughness (mean square slope) and latent heat flux. Level 3 gridded versions of the L2 products have also been developed. A set of Level 4 products have also been developed specifically for direct tropical cyclone overpasses. These include the storm intensity (peak sustained winds) and size (radius of maximum winds), its extent (34, 50 and 64 knot wind radii), and its integrated kinetic energy. Results of measurements made during the 2017 Atlantic hurricane season, including frequent overpasses of Hurricanes Harvey, Irma and Maria, will be presented.

EO-1 Data Quality and Sensor Stability with Changing Orbital Precession at the End of a 16 Year Mission

NASA Technical Reports Server (NTRS)

Franks, Shannon; Neigh, Christopher S. R.; Campbell, Petya K.; Sun, Guoqing; Yao, Tian; Zhang, Qingyuan; Huemmrich, Karl F.; Middleton, Elizabeth M.; Ungar, Stephen G.; Frye, Stuart W.

2017-01-01

The Earth Observing One (EO-1) satellite has completed 16 years of Earth observations in early 2017. What started as a technology mission to test various new advancements turned into a science and application mission that extended many years beyond the satellites planned life expectancy. EO-1s primary instruments are spectral imagers: Hyperion, the only civilian full spectrum spectrometer (430-2400 nm) in orbit; and the Advanced Land Imager (ALI), the prototype for Landsat-8s pushbroom imaging technology. Both Hyperion and ALI instruments have continued to perform well, but in February 2011 the satellite ran out of the fuel necessary to maintain orbit, which initiated a change in precession rate that led to increasingly earlier equatorial crossing times during its last five years. The change from EO-1s original orbit, when it was formation flying with Landsat-7 at a 10:01am equatorial overpass time, to earlier overpass times results in image acquisitions with increasing solar zenith angles (SZAs). In this study, we take several approaches to characterize data quality as SZAs increased. Our results show that for both EO-1 sensors, atmospherically corrected reflectance products are within 5 to 10 of mean pre-drift products. No marked trend in decreasing quality in ALI or Hyperion is apparent through 2016, and these data remain a high quality resource through the end of the mission.

NPP VIIRS and Aqua MODIS RSB Comparison Using Observations from Simultaneous Nadir Overpasses (SNO)

NASA Technical Reports Server (NTRS)

Xiong, X.; Wu, A.

2012-01-01

Suomi NPP (National Polar-orbiting Partnership) satellite (http://npp.gsfc.nasa.gov/viirs.html) began to daily collect global data following its successful launch on October 28, 2011. The Visible Infrared Imaging Radiometer Suite (VIIRS) is a key NPP sensor. Similar to the design of the OLS, SeaWiFS and MODIS instruments, VIIRS has on-board calibration components including a solar diffuser (SD) and a solar diffuser stability monitor (SDSM) for the reflective solar bands (RSB), a V-groove blackbody for the thermal emissive bands (TEB), and a space view (SV) port for background subtraction. Immediately after the VIIRS nadir door s opening on November 21, 2011, anomalously large degradation in the SD response was identified in the near-IR wavelength region, which was unexpected as decreases in the SD reflectance usually occur gradually in the blue (0.4 m) wavelength region based on past experience. In this study, we use a well-calibrated Aqua MODIS as reference to track and evaluate VIIRS RSB stability and performance. Reflectances observed by both sensors from simultaneous nadir overpasses (SNO) are used to determine VIIRS to MODIS reflectance ratios for their spectral matching bands. Results of this study provide an immediate post-launch assessment, independent validation of the anomalous degradation observed in SD measurements at near-IR wavelengths and initial analysis of calibration stability and consistency.

Discharge estimation in ungauged basins through variational data assimilation : The potential of the SWOT mission.

NASA Astrophysics Data System (ADS)

Oubanas, H.; Gejadze, I.; Malaterre, P. O.; Durand, M. T.; Wei, R.; Frasson, R. P. M.; Domeneghetti, A.

2017-12-01

This work investigates the estimation of river discharge from simulated observations of the forthcoming Surface Water and Ocean Topography (SWOT) mission, to be launched in 2021, using a variant of the standard variational data assimilation method `4D-Var'. The hydrology SWOT simulator, developed at the Jet Propulsion Laboratory (JPL) has been used to simulate the expected performance of the KaRIn instrument onboard the satellite, producing synthetic SWOT observations of height and width, at each satellite overpass. SWOT data products were synthesized at the spatial scale of 200 m along the river centerline. Using a 1.5D full Saint-Venant hydraulic model, variational data assimilation simultaneously estimates the inflow discharge, river bathymetry and bed roughness. The proposed method has been designed for an application to fully ungauged basins; therefore, the prior information is derived from the SWOT observations only and the globally available ancillary information. Two reaches of the Po and Sacramento Rivers of about 130 km and 150 km, respectively, have been considered in this study. Discharge was successfully recovered at the overpass time with a relative-root-mean-square error of 16% and 12.3% for the Po and Sacramento Rivers, respectively. The estimates of the bed level and the roughness coefficient demonstrate a local improvement; however they may not provide reliable global information of the river bathymetry and roughness.

Remote sensing applications to hydrologic modeling in the southern Sierra Nevada and portions of the San Joaquin Valley, volume 1. [including geographic description of the Fergana area of the U.S.S.R.

NASA Technical Reports Server (NTRS)

Dozier, J.; Estes, J. E.; Simonett, D. S. (Principal Investigator); Davis, R.; Frew, J.; Gold, C.; Keith, S.; Marks, D.

1978-01-01

The author has identified the following significant results. Characteristics of LANDSAT MSS imagery present problems in using satellite radiation measurements to estimate the shortwave albedo of an alpine snow cover. Every 15 minute USGS quadrangle contains over 100,000 pixels which poses a computation problem if each pixel is to be evaluated individually. The sampling interval may be sufficiently great to mask some effects of terrain and vegetation on reflectance. Three frames of LANDSAT imagery are needed for complete coverage of the study area, yet less than one third of the area coverage from each frame covers an area of interest. Because of distortions inherent in the imagery, information regarding spacecraft altitude, attitude, and position must be statistically derived with respect to ground control points in the image whose geodetic locations are known. An inspection of shade points indicates that up to one third of the most heavily snow covered areas may saturate in bands 4 through 6. LANDSAT's 9 day repeat cycle is not optimum for snow cover reflectance modeling because the most pronounced changes in albedo occur most nearly following a new snowfall. Such a snowfall, occurring between overpasses, is inadequately represented by extrapolation from the previous overpasses.

Radiometric Cross-calibration of KOMPSAT-3A with Landsat-8

NASA Astrophysics Data System (ADS)

Shin, D. Y.; Ahn, H. Y.; Lee, S. G.; Choi, C. U.; Kim, J. S.

2016-06-01

In this study, Cross calibration was conducted at the Libya 4 PICS site on 2015 using Landsat-8 and KOMPSAT-3A. Ideally a cross calibration should be calculated for each individual scene pair because on any given date the TOA spectral profile is influenced by sun and satellite view geometry and the atmospheric conditions. However, using the near-simultaneous images minimizes this effect because the sensors are viewing the same atmosphere. For the cross calibration, the calibration coefficient was calculated by comparing the at sensor spectral radiance for the same location calculated using the Landsat-8 calibration parameters in metadata and the DN of KOMPSAT-3A for the regions of interest (ROI). Cross calibration can be conducted because the satellite sensors used for overpass have a similar bandwidth. However, not all satellites have the same color filter transmittance and sensor reactivity, even though the purpose is to observe the visible bands. Therefore, the differences in the RSR should be corrected. For the cross-calibration, a calibration coefficient was calculated using the TOA radiance and KOMPSAT-3 DN of the Landsat-8 OLI overpassed at the Libya 4 Site, As a result, the accuracy of the calibration coefficient at the site was assumed to be ± 1.0%. In terms of the results, the radiometric calibration coefficients suggested here are thought to be useful for maintaining the optical quality of the KOMPSAT-3A.

Urban spaces adopted by the performing arts

NASA Astrophysics Data System (ADS)

Case, Alexander U.

2004-05-01

No celebration of acoustics in New York City would be complete without mention of the countless alternative spaces used for the perfor- mance of music, dance, and other art forms. New York's countless train stations, parks, alleys, and overpasses provide popular venues for artists to make sound. Lincoln Center and Carnegie get all the glory, but it's the streets and train stations that do all the work. This work surveys some of these alternative performance spaces and their acoustic contribution to the performance.

Reducing losses from earthquakes through personal preparedness

USGS Publications Warehouse

Kockelman, W.J.

1985-01-01

A prerequisite to personal preparedness is familiarity with and concern about the other hazard-reduction phases. Strengthening the structure of the home, storing water, and showing family members how to shut off utility-supply lines are only a part of personal preparedness. Equally important are other phases such as picking up children from an evacuated school, securing heavy objects at the work palce as well as in the home, and retrofitting the commuter-highway overpasses needed to reunite a family. 

GOES Satellite Observations for the FIRE/SRB Wisconsin Experiment Region from October 11 Through November 2, 1986

NASA Technical Reports Server (NTRS)

Whitlock, Charles H.; T R. acraitch, Eric J.

1987-01-01

A map, concise tables, and satellite images are presented which show ground-site locations, GOES visible/infrared instrument counts above each site, and cloud spatial distribution for the experiment region from 11 October through 2 November 1986. The cloud images are presented near times of the afternoon NOAA-9 satellite overpasses in order to provide a qualitative aid in the interpretation of TOVS, AVHRR, and heat budget data during the FIRE/SRB experiment.

A summary of the test procedures and operational details of a Delaware River and an ocean dumping pollution monitoring experiment conducted 28 August 1975

NASA Technical Reports Server (NTRS)

Hypes, W. D.; Ohlhorst, C. W.

1977-01-01

Two remote sensor evaluation experiments are discussed. One experiment was conducted at the DuPont acid-dump site off the Delaware coast. The second was conducted at an organic waste outfall in the Delaware River. The operational objective of obtaining simultaneous sea truth sampling with remote sensors overpasses was met. Descriptions of the test sites, sensors, sensor platforms, flight lines, sea truth data collected, and operational chronology are presented.

A summary of the test procedures and operational details of an ocean dumping pollution monitoring experiment conducted 7 October 1976

NASA Technical Reports Server (NTRS)

Hypes, W. D.; Wallace, J. W.; Gurganus, E. A.

1977-01-01

A remote sensor experiment was conducted at a sewage sludge dump site off the Delaware/Maryland coast. Two aircraft serving as remote sensor platforms flew over the dump site during a sludge dump. One aircraft carried a multispectral scanner and the other aircraft carried a rapid scanning spectrometer. Data from sea-truth stations were collected concurrent with overpasses of the aircraft. All sensors were operational and produced good digital data.

Expected Performance of the Upcoming Surface Water and Ocean Topography Mission Measurements of River Height, Width, and Slope

NASA Astrophysics Data System (ADS)

Wei, R.; Frasson, R. P. M.; Williams, B. A.; Rodriguez, E.; Pavelsky, T.; Altenau, E. H.; Durand, M. T.

2017-12-01

The upcoming Surface Water and Ocean Topography (SWOT) mission will measure river widths and water surface elevations of rivers wider than 100 m. In preparation for the SWOT mission, the Jet Propulsion Laboratory built the SWOT hydrology simulator with the intent of generating synthetic SWOT overpasses over rivers with realistic error characteristics. These synthetic overpasses can be used to guide the design of processing methods and data products, as well as develop data assimilation techniques that will incorporate the future SWOT data into hydraulic and hydrologic models as soon as the satellite becomes operational. SWOT simulator uses as inputs water depth, river bathymetry, and the surrounding terrain digital elevation model to create simulated interferograms of the study area. Next, the simulator emulates the anticipated processing of SWOT data by attempting to geolocate and classify the radar returns. The resulting cloud of points include information on water surface elevation, pixel area, and surface classification (land vs water). Finally, we process the pixel clouds by grouping pixels into equally spaced nodes located at the river centerline. This study applies the SWOT simulator to six different rivers: Sacramento River, Tanana River, Saint Lawrence River, Platte River, Po River, and Amazon River. This collection of rivers covers a range of size, slope, and planform complexity with the intent of evaluating the impact of river width, slope, planform complexity, and surrounding topography on the anticipated SWOT height, width, and slope error characteristics.

EO-1 data quality and sensor stability with changing orbital precession at the end of a 16 year mission

PubMed Central

Franks, Shannon; Neigh, Christopher S.R.; Campbell, Petya K.; Sun, Guoqing; Yao, Tian; Zhang, Qingyuan; Huemmrich, Karl F.; Middleton, Elizabeth M.; Ungar, Stephen G.; Frye, Stuart W.

2018-01-01

The Earth Observing One (EO-1) satellite has completed 16 years of Earth observations in early 2017. What started as a technology mission to test various new advancements turned into a science and application mission that extended many years beyond the satellite’s planned life expectancy. EO-1’s primary instruments are spectral imagers: Hyperion, the only civilian full spectrum spectrometer (430–2400 nm) in orbit; and the Advanced Land Imager (ALI), the prototype for Landsat-8’s pushbroom imaging technology. Both Hyperion and ALI instruments have continued to perform well, but in February 2011 the satellite ran out of the fuel necessary to maintain orbit, which initiated a change in precession rate that led to increasingly earlier equatorial crossing times during its last five years. The change from EO-1’s original orbit, when it was formation flying with Landsat-7 at a 10:01am equatorial overpass time, to earlier overpass times results in image acquisitions with increasing solar zenith angles (SZAs). In this study, we take several approaches to characterize data quality as SZAs increased. Our results show that for both EO-1 sensors, atmospherically corrected reflectance products are within 5 to 10% of mean pre-drift products. No marked trend in decreasing quality in ALI or Hyperion is apparent through 2016, and these data remain a high quality resource through the end of the mission. PMID:29651338

[Around biological evolution. Reflections of a physicist].

PubMed

Sanchez-Palencia, Evariste

2016-01-01

This text is the written version of a talk at the Société de Biologie on February 17, 2016. It contains reflections of a non-biologist scientist on general problems of biological evolution, including the kind of causality involved, the ideas emerging from it, in particular the constructive and structuring character of phenomena such as predation, the role of stability and attractors. This leads to a larger reflection on dialectics, the general framework of evolving processes, which overpasses formal logic and instantaneousness. © Société de Biologie, 2016.

Multidate mapping of mosquito habitat. [Nebraska, South Dakota

NASA Technical Reports Server (NTRS)

Woodzick, T. L.; Maxwell, E. L.

1977-01-01

LANDSAT data from three overpasses formed the data base for a multidate classification of 15 ground cover categories in the margins of Lewis and Clark Lake, a fresh water impoundment between South Dakota and Nebraska. When scaled to match topographic maps of the area, the ground cover classification maps were used as a general indicator of potential mosquito-breeding habitat by distinguishing productive wetlands areas from nonproductive nonwetlands areas. The 12 channel multidate classification was found to have an accuracy 23% higher than the average of the three single date 4 channel classifications.

Ground-based determination of atmospheric radiance for correction of ERTS-1 data

NASA Technical Reports Server (NTRS)

Peacock, K.

1974-01-01

A technique is described for estimating the atmospheric radiance observed by a downward sensor (ERTS) using ground-based measurements. A formula is obtained for the sky radiance at the time of the ERTS overpass from the radiometric measurement of the sky radiance made at a particular solar zenith angle and air mass. A graph illustrates ground-based sky radiance measurements as a function of the scattering angle for a range of solar air masses. Typical values for sky radiance at a solar zenith angle of 48 degrees are given.

Preliminary evaluation of the airborne imaging spectrometer for vegetation analysis

NASA Technical Reports Server (NTRS)

Strahler, A. H.; Woodcock, C. E.

1984-01-01

The primary goal of the project was to provide ground truth and manual interpretation of data from an experimental flight of the Airborne Infrared Spectrometer (AIS) for a naturally vegetated test site. Two field visits were made; one trip to note snow conditions and temporally related vegetation states at the time of the sensor overpass, and a second trip following acquisition of prints of the AIS images for field interpretation. Unfortunately, the ability to interpret the imagery was limited by the quality of the imagery due to the experimental nature of the sensor.

Reduced solar-induced chlorophyll fluorescence from GOME-2 during Amazon drought caused by dataset artifacts.

PubMed

Zhang, Yao; Joiner, Joana; Gentine, Pierre; Zhou, Sha

2018-06-01

Recently, Yang et al. () reported a decrease in solar-induced chlorophyll fluorescence (SIF) during 2015/2016 El Niño event albeit the increase in enhanced vegetation index (EVI). They interpreted the reduced SIF as a signal of reduced ecosystem photosynthesis. However, we argue that the reduced SIF during 2015/2016 is caused by a decreasing trend of SIF due to sensor degradation and the satellite overpass time is critical for drought impact assessment. © 2018 John Wiley & Sons Ltd.

Design of the compact high-resolution imaging spectrometer (CHRIS), and future developments

NASA Astrophysics Data System (ADS)

Cutter, Mike; Lobb, Dan

2017-11-01

The CHRIS instrument was launched on ESA's PROBA platform in October 2001, and is providing hyperspectral images of selected ground areas at 17m ground sampling distance, in the spectral range 415nm to 1050nm. Platform agility allows image sets to be taken at multiple view angles in each overpass. The design of the instrument is briefly outlined, including design of optics, structures, detection and in-flight calibration system. Lessons learnt from construction and operation of the experimental system, and possible design directions for future hyperspectral systems, are discussed.

Combined VSWIR/TIR Products Overview: Issues and Examples

NASA Technical Reports Server (NTRS)

Knox, Robert G.

2010-01-01

The presentation provides a summary of VSWIR data collected at 19-day intervals for most areas. TIR data was collected both day and night on a 5-day cycle (more frequently at higher latitudes), the TIR swath is four times as wide as VSWIR, and the 5-day orbit repeat is approximate. Topics include nested swath geometry for reference point design and coverage simulations for sample FLUXNET tower sites. Other points examined include variation in latitude for revisit frequency, overpass times, and TIR overlap geometry and timing between VSWIR data collections.

Discharge Estimation in Ungauged Basins Through Variational Data Assimilation: The Potential of the SWOT Mission

NASA Astrophysics Data System (ADS)

Oubanas, H.; Gejadze, I.; Malaterre, P.-O.; Durand, M.; Wei, R.; Frasson, R. P. M.; Domeneghetti, A.

2018-03-01

Space-borne instruments can measure river water surface elevation, slope, and width. Remote sensing of river discharge in ungauged basins is far more challenging, however. This work investigates the estimation of river discharge from simulated observations of the forthcoming Surface Water and Ocean Topography (SWOT) satellite mission using a variant of the classical variational data assimilation method "4D-Var." The variational assimilation scheme simultaneously estimates discharge, river bathymetry, and bed roughness in the context of a 1.5 D full Saint-Venant hydraulic model. Algorithms and procedures are developed to apply the method to fully ungauged basins. The method was tested on the Po and Sacramento Rivers. The SWOT hydrology simulator was used to produce synthetic SWOT observations at each overpass time by simulating the interaction of SWOT radar measurements with the river water surface and nearby land surface topography at a scale of approximately 1 m, thus accounting for layover, thermal noise, and other effects. SWOT data products were synthesized by vectorizing the simulated radar returns, leading to height and width estimates at 200 m increments along the river centerlines. The ingestion of simulated SWOT data generally led to local improvements on prior bathymetry and roughness estimates which allowed the prediction of river discharge at the overpass times with relative root mean squared errors of 12.1% and 11.2% for the Po and Sacramento Rivers, respectively. Nevertheless, equifinality issues that arise from the simultaneous estimation of bed elevation and roughness may prevent their use for different applications, other than discharge estimation through the presented framework.

Ground-based intercomparisons of SBUV/2 flight instruments the world standard Dobson spectrophotometer 83 and overpass observations from Nimbus-7 TOMS and NOAA-11 SBUV/2

NASA Technical Reports Server (NTRS)

Heath, D. F.; Ahmad, Z.; Torres, O.; Evans, R. D.; Grass, R. D.; Komhyr, W. A.; Nelson, W.

1994-01-01

Total ozone data obtained during summers at Mauna Loa Observatory, Hawaii, with Dobson Spectrophotometer 83 are routinely compared with overpass total ozone data from the Total Ozone Mapping Spectrometer (TOMS) and the Solar Backscatter Ultraviolet (SBUV) spectrometer launched aboard the Nimbus 7 satellite in 1978. Results from the TOMS/Dobson instrument comparisons through 1990 have been presented by McPeters and Komhyr (1991). Dobson spectrophotometer 83 was established as the standard instrument for the U.S.A. Dobson instrument station network in 1962. In 1980, the instrument was designated by the World Meteorological Organization (WMO) as the Standard Dobson Spectrophotometer for the World. Long-term ozone measurement precision of the instrument has been maintained at plus or minus 0.5 percent (Komhyr et al., 1989). On an absolute scale, the ozone measurement accuracy of the instrument is estimated to plus or minus 3 percent. In early April, 1990, comparison of total ozone and vertical distribution (Umkehr) observations were made for the first time with Dobson spectrophotometer 8.3. The work was conducted at the NOAA Climate Monitoring and Diagnostics Laboratory (CMDL) in Boulder, Colorado, and at the research and instrument manufacturing facility of the Ball Aerospace System Division located about 2 km east of Boulder. (The SBUV-2 S/N-2 instrument, built by Ball Aerospace Systems Division, is scheduled for launch aboard the NOAA-13 satellite). We present results of the comparisons which include ozone vertical distribution data obtained with a balloon-borne electrochemical concentration cell (ECC) ozonesonde (Komhyr, 1969).

AATSR land surface temperature product algorithm verification over a WATERMED site

NASA Astrophysics Data System (ADS)

Noyes, E. J.; Sòria, G.; Sobrino, J. A.; Remedios, J. J.; Llewellyn-Jones, D. T.; Corlett, G. K.

A new operational Land Surface Temperature (LST) product generated from data acquired by the Advanced Along-Track Scanning Radiometer (AATSR) provides the opportunity to measure LST on a global scale with a spatial resolution of 1 km2. The target accuracy of the product, which utilises nadir data from the AATSR thermal channels at 11 and 12 μm, is 2.5 K for daytime retrievals and 1.0 K at night. We present the results of an experiment where the performance of the algorithm has been assessed for one daytime and one night time overpass occurring over the WATERMED field site near Marrakech, Morocco, on 05 March 2003. Top of atmosphere (TOA) brightness temperatures (BTs) are simulated for 12 pixels from each overpass using a radiative transfer model, with the LST product and independent emissivity values and atmospheric data as inputs. We have estimated the error in the LST product over this biome for this set of conditions by applying the operational AATSR LST retrieval algorithm to the modelled BTs and comparing the results with the original AATSR LSTs input into the model. An average bias of -1.00 K (standard deviation 0.07 K) for the daytime data, and -1.74 K (standard deviation 0.02 K) for the night time data is obtained, which indicates that the algorithm is yielding an LST that is too cold under these conditions. While these results are within specification for daytime retrievals, this suggests that the target accuracy of 1.0 K at night is not being met within this biome.

GPM observations of a tropical-like hailstorm over the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Cinzia Marra, Anna; Panegrossi, Giulia; Casella, Daniele; Sanò, Paolo; Dietrich, Stefano; Baldini, Luca; Petracca, Marco; Porcù, Federico

2016-04-01

In the last years tropical-like precipitation systems, i.e., with large horizontal extent, tropical cyclone features (i.e., Medicanes), or characterized by very deep and intense convection, have become more and more frequent also at mid-latitudes. On September 05, 2015 a violent hailstorm hit the Gulf and the city of Naples in Italy. The storm was caused by a southward plunge of the jet stream that carved into Western Europe, sending an upper disturbance into the Italian peninsula. That instability, associated with high Sea Surface Temperature (SST), and low-level convergence, stirred up an impressive severe thunderstorm with intense lightning activity and strong winds, that started developing around 0600 UTC over the Thyrrenian Sea off the coast of Naples, and reached maturity by 0637 UTC, hitting the coast around 0900 UTC, moving inland afterwards, until its complete dissipation around 1200 UTC. The storm dropped 5-8 cm diameter hailstones along its path over the sea, and in Pozzuoli, near Naples. Meteosat Second Generation (MSG) SEVIRI VIS/IR images show the extremely rapid development of the thunderstorm, with cloud-top temperatures (at 10.8 μm) dropping from 270 K at 0657 UTC to the extremely low value of 205 K at 0637 UTC (65 K in 40 minutes). The occurrence of a very well defined convective overshooting top is evidenced by the VIS images. Sounding at Pratica di Mare station (180 km NE of Naples) at 0000 UTC shows the tropopause height at about 13.5 km and the typical "loaded gun" features providing a strong capping inversion inhibiting the premature release of the convective instability: moist air in the boundary layer, due to the low-level southerly flow, with warm and dry air aloft. The LINET ground-based lightning detection network registered over 37000 strokes between 0500 and 1200 UTC. During its mature phase, at 0845 UTC, the hailstorm was captured by one overpass of Global Precipitation Measurement (GPM) satellite launched in February 2014. The GPM Core Observatory (GPM-CO), equipped with the GPM Microwave Imager (GMI), the most advanced multichannel conical-scanning microwave radiometer available, and with the Ka/Ku band Dual-frequency Precipitation Radar (DPR), provides unique measurements of extremely rare, tropical-like features of the storm. Close-in-time observations of the hailstorm are also available from the AMSU/MHS radiometers (MetOp-A overpass at 0834 UTC and MetOp-B overpass at 0929 UTC). DPR shows vertical extension of more than 16 km a.s.l. and with tropical-like reflectivity values (40dBZ top height at 14 km and 20 dBZ top height at 16 km, sign of strong updraft, supporting large ice hydrometeors), confirming the presence of a deep overshooting above the 13.5 km tropopause. GMI observations show strong brightness temperature (TB) depressions, with the 37GHz, 89GHz, and 166GHz as low as 97K, 67K, and 87K, respectively, similar in both V and H channels (sign of round shaped ice hydrometeors). Such low values of TB are extremely unusual ad mid latitudes, and can be measured only thanks to the high-resolution capability of GMI. The analysis of the TB differences in the three AMSU/MHS 183 GHz water vapor channels, usually applied to tropical convective clouds, confirms the presence of convective overshooting. Around the time of the GMI (and AMSU/MHS) overpass (between 08:30 and 09:00 UTC), the LINET registered about 5000 lightning strokes (3500 intracloud), another indication of the severity of the storm. In this study GPM observations will be thoroughly analyzed and discussed, along with the analysis of other spaceborne and ground-based measurements, providing observational evidence of the severity and rarity of this type of storm at mid-latitudes.

Houston area multicrop inspection trips. [Wharton County, Texas

NASA Technical Reports Server (NTRS)

Dunham, E. W. (Principal Investigator)

1980-01-01

The phenology of crops such as corn, cotton, soybeans, sorghum, sunflowers, and rice and their observed signatures on LANDSAT imagery was studied. This was accomplished by photographing the various crops in segments 275 and 276 located in Wharton County, Texas and comparing those photographs with LANDSAT imagery of the same dates. These comparisons gave insight as to why a particular crop growth stage appeared as a definite signature on LANDSAT and how the percentage of ground cover of various crops affected the signatures on LANDSAT imagery. Numerous crop growth stages could not be directly compared due to cloud cover during several LANDSAT overpasses.

ROCOZ-A (improved rocket launched ozone sensor) for middle atmosphere ozone measurements

NASA Technical Reports Server (NTRS)

Lee, H. S.; Parsons, C. L.

1987-01-01

An improved interference filter based ultraviolet photometer (ROCOZ-A) for measuring stratospheric ozone is discussed. The payload is launched aboard a Super-Loki to a typical apogee of 70 km. The instrument measures the solar ultraviolet irradiance as it descends on a parachute. The total cumulative ozone is then calculated based on the Beer-Lambert law. The cumulative ozone precision measured in this way is 2.0% to 2.5% over an altitude range of 20 and 55 km. Results of the intercomparison with the SBUV overpass data and ROCOZ-A data are also discussed.

Distribution and concentration of suspended matter in Delaware Bay

NASA Technical Reports Server (NTRS)

Klemas, V. (Principal Investigator); Philpot, W.

1977-01-01

The author has identified the following significant results. The problem of remote sensing of suspended matter in water was analyzed in terms of the single-scattering albedo, and a semiempirical relationship between satellite radiance measurements and the concentration of suspended matter in the water was developed. The relationship was tested using data from the 7 July 1973 LANDSAT overpass of Delaware Bay with good results. Suspended sediment concentration maps for the entire Delaware Bay were prepared using radiance values extracted from LANDSAT MSS imagery and correlating them with ground truth samples collected from boats and helicopter.

NASA CloudSat Looks Hurricane Nichole in the Eye

NASA Image and Video Library

2016-10-14

NASA's CloudSat satellite completed an eye overpass of Hurricane Nicole on Oct. 12, 2016, at 10:55 a.m. PDT (17:55 UTC) as the storm was moving toward Bermuda. At the time the system had sustained winds of 109 miles per hour (95 knots), with a minimum pressure of 962 millibars. CloudSat viewed the system just as it was going through a period of intensification (from 98 miles per hour, or 85 knots, to 121 miles per hour (105 knots) during a 12-hour period. http://photojournal.jpl.nasa.gov/catalog/PIA21098

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sokaras, D.; Andrianis, M.; Lagoyannis, A.

The cascade L-shell x-ray emission as an incident polarized and unpolarized monochromatic radiation overpass the 1s ionization threshold is investigated for the metallic Fe by means of moderate resolution, quantitative x-ray spectrometry. A full ab initio theoretical investigation of the L-shell x-ray emission processes is performed based on a detailed straightforward construction of the cascade decay trees within the Pauli-Fock approximation. The agreement obtained between experiments and the presented theory is indicated and discussed with respect to the accuracy of advanced atomic models as well as its significance for the characterization capabilities of x-ray fluorescence (XRF) analysis.

Sulfur Dioxide Emissions from Congo Volcanoes

NASA Technical Reports Server (NTRS)

2002-01-01

The Earth Probe Total Ozone Mapping Spectrometer (TOMS) detected a sulfur dioxide cloud associated with the January 2002 eruption of Nyiragongo as it flew over the region at around 11 a.m. local time (0900 UTC) on January 17. The sensor detected no significant amounts of ash in the eruption cloud. At the time of the TOMS overpass the cloud extended up to roughly 200 km (124 miles) northwest of Nyiragongo and was still attached to the volcano. This observation is consistent with nearly coincident MODIS imagery which shows an opaque cloud of gas and steam in the same location. The TOMS measurements show that the amount of sulfur dioxide in the Nyiragongo's plume range from about 10 to 30 kilotons. Please note that TOMS mass retrievals are dependent on the altitude of the cloud and may be adjusted as more information becomes available. Since the cloud may still have been developing at the time of the TOMS overpass, the final sulfur dioxide burden may have been greater. Wind trajectory data (courtesy of Leslie Lait, SSAI) suggest that part of the cloud may have reached at least mid- to upper-tropospheric altitudes of up to 12 km (7 miles), but scientists suspect no significant stratospheric injection of sulfur dioxide as a result of this eruption since the gas was not visible over the Democratic Republic of the Congo region in subsequent TOMS data acquired on January 18. Production of sulfur dioxide without a significant ash cloud is commonly observed during effusive eruptions such as the Nyiragongo event. Although dense low-level ash may be produced during such eruptions, these particulates usually fall out fairly quickly and elude detection by satellite. The size of the January 17 Nyiragongo cloud and the estimated sulfur dioxide tonnage are fairly modest, and at least an order of magnitude smaller than values typically measured by TOMS during eruptions of nearby Nyamuragira during its frequent outbursts (e.g., on February 6, 2001). Sulfur dioxide column amounts (measured in Dobson Units) are much higher in the more extensive Nyamuragira cloud, which contained roughly 420 kilotons of sulfur dioxide. Although several factors could affect the size of the observed cloud in each case-such as the delay between the onset of the eruption and the TOMS overpass, and the volume of lava emitted and the lava composition-the TOMS data suggest that the Nyiragongo magma may have been largely degassed before eruption. One possible mechanism by which this could be achieved is the cyclic degassing of magma in the subaerial lava lakes that have been intermittently present in Nyiragongo's summit crater over the past few decades. Images courtesy Simon Cairn, TOMS Volcanic Emissions Group, Joint Center for Earth Systems Technology, University of Maryland-Baltimore County

Physical Validation of TRMM TMI and PR Monthly Rain Products Over Oklahoma

NASA Technical Reports Server (NTRS)

Fisher, Brad L.

2004-01-01

The Tropical Rainfall Measuring Mission (TRMM) provides monthly rainfall estimates using data collected by the TRMM satellite. These estimates cover a substantial fraction of the earth's surface. The physical validation of TRMM estimates involves corroborating the accuracy of spaceborne estimates of areal rainfall by inferring errors and biases from ground-based rain estimates. The TRMM error budget consists of two major sources of error: retrieval and sampling. Sampling errors are intrinsic to the process of estimating monthly rainfall and occur because the satellite extrapolates monthly rainfall from a small subset of measurements collected only during satellite overpasses. Retrieval errors, on the other hand, are related to the process of collecting measurements while the satellite is overhead. One of the big challenges confronting the TRMM validation effort is how to best estimate these two main components of the TRMM error budget, which are not easily decoupled. This four-year study computed bulk sampling and retrieval errors for the TRMM microwave imager (TMI) and the precipitation radar (PR) by applying a technique that sub-samples gauge data at TRMM overpass times. Gridded monthly rain estimates are then computed from the monthly bulk statistics of the collected samples, providing a sensor-dependent gauge rain estimate that is assumed to include a TRMM equivalent sampling error. The sub-sampled gauge rain estimates are then used in conjunction with the monthly satellite and gauge (without sub- sampling) estimates to decouple retrieval and sampling errors. The computed mean sampling errors for the TMI and PR were 5.9% and 7.796, respectively, in good agreement with theoretical predictions. The PR year-to-year retrieval biases exceeded corresponding TMI biases, but it was found that these differences were partially due to negative TMI biases during cold months and positive TMI biases during warm months.

Validation of TES ammonia observations at the single pixel scale in the San Joaquin Valley during DISCOVER-AQ

NASA Astrophysics Data System (ADS)

Sun, Kang; Cady-Pereira, Karen; Miller, David J.; Tao, Lei; Zondlo, Mark A.; Nowak, John B.; Neuman, J. A.; Mikoviny, Tomas; Müller, Markus; Wisthaler, Armin; Scarino, Amy J.; Hostetler, Chris A.

2015-05-01

Ammonia measurements from a vehicle-based, mobile open-path sensor and those from aircraft were compared with Tropospheric Emission Spectrometer (TES) NH3 columns at the pixel scale during the NASA Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality field experiment. Spatial and temporal mismatches were reduced by having the mobile laboratory sample in the same areas as the TES footprints. To examine how large heterogeneities in the NH3 surface mixing ratios may affect validation, a detailed spatial survey was performed within a single TES footprint around the overpass time. The TES total NH3 column above a single footprint showed excellent agreement with the in situ total column constructed from surface measurements with a difference of 2% (within the combined measurement uncertainties). The comparison was then extended to a TES transect of nine footprints where aircraft data (5-80 ppbv) were available in a narrow spatiotemporal window (<10 km, <1 h). The TES total NH3 columns above the nine footprints agreed to within 6% of the in situ total columns derived from the aircraft-based measurements. Finally, to examine how TES captures surface spatial gradients at the interpixel scale, ground-based, mobile measurements were performed directly underneath a TES transect, covering nine footprints within ±1.5 h of the overpass. The TES total columns were strongly correlated (R2 = 0.82) with the median NH3 mixing ratios measured at the surface. These results provide the first in situ validation of the TES total NH3 column product, and the methodology is applicable to other satellite observations of short-lived species at the pixel scale.

A Vertical Census of Precipitation Characteristics using Ground-based Dual-polarimetric Radar Data

NASA Astrophysics Data System (ADS)

Wolff, D. B.; Petersen, W. A.; Marks, D. A.; Pippitt, J. L.; Tokay, A.; Gatlin, P. N.

2017-12-01

Characterization of the vertical structure/variability of precipitation and resultant microphysics is critical in providing physical validation of space-based precipitation retrievals. In support of NASAs Global Precipitation Measurement (GPM) mission Ground Validation (GV) program, NASA has invested in a state-of-art dual-polarimetric radar known as NPOL. NPOL is routinely deployed on the Delmarva Peninsula in support of NASAs GPM Precipitation Research Facility (PRF). NPOL has also served as the backbone of several GPM field campaigns in Oklahoma, Iowa, South Carolina and most recently in the Olympic Mountains in Washington state. When precipitation is present, NPOL obtains very high-resolution vertical profiles of radar observations (e.g. reflectivity (ZH) and differential reflectivity (ZDR)), from which important particle size distribution parameters are retrieved such as the mass-weight mean diameter (Dm) and the intercept parameter (Nw). These data are then averaged horizontally to match the nadir resolution of the dual-frequency radar (DPR; 5 km) on board the GPM satellite. The GPM DPR, Combined, and radiometer algorithms (such as GPROF) rely on functional relationships built from assumed parametric relationships and/or retrieved parameter profiles and spatial distributions of particle size (PSD), water content, and hydrometeor phase within a given sample volume. Thus, the NPOL-retrieved profiles provide an excellent tool for characterization of the vertical profile structure and variability during GPM overpasses. In this study, we will use many such overpass comparisons to quantify an estimate of the true sub-IFOV variability as a function of hydrometeor and rain type (convective or stratiform). This presentation will discuss the development of a relational database to help provide a census of the vertical structure of precipitation via analysis and correlation of reflectivity, differential reflectivity, mean-weight drop diameter and the normalized intercept parameter of the gamma drop size distribution.

Validation of Ground-based Optical Estimates of Auroral Electron Precipitation Energy Deposition

NASA Astrophysics Data System (ADS)

Hampton, D. L.; Grubbs, G. A., II; Conde, M.; Lynch, K. A.; Michell, R.; Zettergren, M. D.; Samara, M.; Ahrns, M. J.

2017-12-01

One of the major energy inputs into the high latitude ionosphere and mesosphere is auroral electron precipitation. Not only does the kinetic energy get deposited, the ensuing ionization in the E and F-region ionosphere modulates parallel and horizontal currents that can dissipate in the form of Joule heating. Global models to simulate these interactions typically use electron precipitation models that produce a poor representation of the spatial and temporal complexity of auroral activity as observed from the ground. This is largely due to these precipitation models being based on averages of multiple satellite overpasses separated by periods much longer than typical auroral feature durations. With the development of regional and continental observing networks (e.g. THEMIS ASI), the possibility of ground-based optical observations producing quantitative estimates of energy deposition with temporal and spatial scales comparable to those known to be exhibited in auroral activity become a real possibility. Like empirical precipitation models based on satellite overpasses such optics-based estimates are subject to assumptions and uncertainties, and therefore require validation. Three recent sounding rocket missions offer such an opportunity. The MICA (2012), GREECE (2014) and Isinglass (2017) missions involved detailed ground based observations of auroral arcs simultaneously with extensive on-board instrumentation. These have afforded an opportunity to examine the results of three optical methods of determining auroral electron energy flux, namely 1) ratio of auroral emissions, 2) green line temperature vs. emission altitude, and 3) parametric estimates using white-light images. We present comparisons from all three methods for all three missions and summarize the temporal and spatial scales and coverage over which each is valid.

Assessing the potential of Sun-Induced Fluorescence and the Canopy Scattering Coefficient to track large-scale vegetation dynamics in Amazon forests

NASA Astrophysics Data System (ADS)

Köhler, P.; Guanter, L.; Kobayashi, H.; Walther, S.

2016-12-01

Two new remote sensing vegetation parameters derived from spaceborne spectrometers and simulated with a three dimensional radiative transfer model have been evaluated in terms of their prospects and drawbacks for the monitoring of dense vegetation canopies: (i) sun-induced chlorophyll fluorescence (SIF), a unique signal emitted by photosynthetically active vegetation and (ii) the canopy scattering coefficient (CSC), a vegetation parameter derived along with the directional area scattering factor (DASF) and expected to be particularly sensitive to leaf optical properties. Here, we present the first global data set of DASF/CSC and examine the potential of CSC and SIF for providing complementary information on the controversially discussed vegetation seasonality in the Amazon rainforest. A comparison between near-infrared SIF derived from the Global Ozone Monitoring Experiment-2 (GOME-2) instrument and the Orbiting Carbon Observatory-2 (OCO-2) (overpass time in the morning and noon, respectively) reveals the response of SIF to instantaneous photosynthetically active radiation (PAR) and the response of SIF to changing pigment concentrations ('green-up'). The observed seasonality of SIF largely depends on the satellite overpass time which is due to changing temporal trajectories of (instantaneous) PAR with daytime. Therefore, GOME-2 SIF reaches its seasonal maximum in October and around February, while OCO-2 SIF peaks in February and November. We further examine anisotropic reflectance characteristics with the finding that the hot spot effect significantly impacts observed GOME-2 SIF values. On the contrary, our sensitivity analysis suggests that CSC is highly independent of sun-sensor geometry as well as atmospheric effects. The slight annual variability of CSC shows a seasonal cycle attributable to variations in leaf area and/or the amount of precipitation, rather supporting the 'green-up' hypothesis for periods of less intense precipitation.

Comparison of ground and satellite based measurements of the fraction of photosynthetically active radiation intercepted by tall-grass prairie

NASA Technical Reports Server (NTRS)

Demetriades-Shah, T. H.; Kanemasu, E. T.; Flitcroft, I.; Su, H.

1991-01-01

The fraction, of photosynthetically active radiation intercepted by vegetation, F(sub ipar) is an important parameter for modeling the interactions between the land-surface and atmosphere and for estimating vegetation biomass productivity. This study was; therefore, an integral part of FIFE. The specific purpose of this experiment was to find out how well definitive measurements of F(sub ipar) on the ground relate to near-ground and satellite based spectral reflectance measurements. Concurrent measurements of F(sub ipar) and ground, helicopter, and satellite based reflectance measurements were taken at thirteen tall-grass prairie sites within the FIFE experimental area. The sites were subjected to various combinations of burning and grazing managements. The ground and helicopter based reflectance measurements were taken on the same day or few days from the time of the overpass of LANDSAT and SPOT satellites. Ground-based reflectance measurements and sun photometer readings taken at the times of the satellite overpasses were used to correct for atmospheric attenuation. Hand-held radiometer spectral indices were strongly correlated with helicopter and satellite based values (r=0.94 for helicopter, 0.93 for LANDSAT Thematic Mapper, and 0.86 for SPOT). However, the ground, helicopter, and satellite based normalized difference spectral vegetation indices showed low sensitivity to changes in F(sub ipar). Reflectance measurements were only moderately well correlated with measurements of F(sub ipar) (r=0.82 for hand-held radiometer, 0.84 for helicopter measurements, and 0.75 for the LANDSAT Thematic Mapper and SPOT). Improved spectral indices which can compensate for site differences are needed in order to monitor F(sub ipar) more reliably.

Contrails and Climate Change: An Investigation of the Role of Aviation-Induced-Cloudiness on the Ireland Climate Using AATSR Imagery

NASA Astrophysics Data System (ADS)

Whelan, Gillian M.; Cawkwell, Fiona; Mannstein, Hermann; Minnis, Patrick

2010-12-01

Contrails, or 'condensation trails', produced in the wake of jet aircraft have been found to have a small but significant global net climate-warming effect [1]. When atmospheric conditions are favorable (i.e. when ambient atmospheric humidity is high and temperature is below a threshold value of typically less than -40oC), contrails can persist for several hours, grow to become several kilometers long and can also trigger additional cirrus- cloud formation as they spread - which can further impact climate! Due to Ireland's proximity to the North Atlantic Flight Corridor, large volumes of high-altitude overflights cross Ireland daily. Contrails are essentially artificial-linear-ice-clouds at a lower temperature than the surrounding atmosphere and so are visible in 1 Km satellite imagery at the 11 and 12 μm wavelengths; but are better detected in the temperature difference image between these two thermal channels. An automated Contrail Detection Algorithm (CDA) is applied to AATSR thermal imagery over Ireland, and the percentage contrail-coverage of each scene determined. Preliminary results, based on 2008 morning and evening AATSR overpasses show a similar annual average contrail-coverage when present of 0.25% and 0.19% respectively, even though air-traffic density is typically several times higher during the morning overpasses. Cases of excessive contrail-coverage, of up to 2.06% have been observed in combination with extensive cirrus-coverage over Ireland. Results from meteorological data indicate more highly favorable atmospheric conditions for contrail formation and persistence in 00h00 and 06h00 radiosonde ascents; which corresponds to a night-time peak in high-altitude flights over Ireland. Furthermore, exceptionally thick contrail-susceptible-atmospheric layers are found in conjunction with cases of excessive satellite-derived- contrail-coverage.

Validation of Improved Broadband Shortwave and Longwave Fluxes Derived From GOES

NASA Technical Reports Server (NTRS)

Khaiyer, Mandana M.; Nordeen, Michele L.; Palikonda, Rabindra; Yi, Yuhong; Minnis, Patrick; Doelling, David R.

2009-01-01

Broadband (BB) shortwave (SW) and longwave (LW) fluxes at TOA (Top of Atmosphere) are crucial parameters in the study of climate and can be monitored over large portions of the Earth's surface using satellites. The VISST (Visible Infrared Solar Split-Window Technique) satellite retrieval algorithm facilitates derivation of these parameters from the Geostationery Operational Environmental Satellites (GOES). However, only narrowband (NB) fluxes are available from GOES, so this derivation requires use of narrowband-to-broadband (NB-BB) conversion coefficients. The accuracy of these coefficients affects the validity of the derived broadband (BB) fluxes. Most recently, NB-BB fits were re-derived using the NB fluxes from VISST/GOES data with BB fluxes observed by the CERES (Clouds and the Earth's Radiant Energy Budget) instrument aboard Terra, a sun-synchronous polar-orbiting satellite that crosses the equator at 10:30 LT. Subsequent comparison with ARM's (Atmospheric Radiation Measurement) BBHRP (Broadband Heating Rate Profile) BB fluxes revealed that while the derived broadband fluxes agreed well with CERES near the Terra overpass times, the accuracy of both LW and SW fluxes decreased farther away from the overpass times. Terra's orbit hampers the ability of the NB-BB fits to capture diurnal variability. To account for this in the LW, seasonal NB-BB fits are derived separately for day and night. Information from hourly SW BB fluxes from the Meteosat-8 Geostationary Earth Radiation Budget (GERB) is employed to include samples over the complete solar zenith angle (SZA) range sampled by Terra. The BB fluxes derived from these improved NB-BB fits are compared to BB fluxes computed with a radiative transfer model.

Comparison of ground and satellite based measurements of the fraction of photosynthetically active radiation intercepted by tall-grass prairie

NASA Technical Reports Server (NTRS)

Demetriades-Shah, T. H.; Kanemasu, E. T.; Flitcroft, I. D.; Su, H.

1992-01-01

The fraction of photosynthetically active radiation intercepted by vegetation, F(sub ipar) is an important parameter for modeling the interactions between the land-surface and atmosphere and for estimating vegetation biomass productivity. This study was, therefore, an integral part of FIFE. The specific purpose of this experiment was to find out how well definitive measurements of F(sub ipar) on the ground relate to near-ground and satellite based spectral reflectance measurements. Concurrent measurements of F(sub ipar) and ground, helicopter, and satellite based reflectance measurements were taken at thirteen tall-grass prairie sites within the FIFE experimental area. The sites were subjected to various combinations of burning and grazing managements. The ground and helicopter based reflectance measurements were taken on the same day or few days from the time of the overpass of LANDSAT and SPOT satellites. Ground-based reflectance measurements and sun photometer readings taken at the times of the satellite overpasses were used to correct for atmospheric attenuation. Hand-held radiometer spectral indices were strongly correlated with helicopter and satellite based values (r = 0.94 for helicopter, 0.93 for LANDSAT Thematic Mapper, and 0.86 for SPOT). However, the ground, helicopter, and satellite based normalized difference spectral vegetation indices showed low sensitivity to changes in F(sub ipar). Reflectance measurements were only moderately well correlated with measurements of F(sub ipar) (r = 0.82 for hand-held radiometer, 0.84 for helicopter measurements, and 0.75 for the LANDSAT Thematic Mapper and SPOT). Improved spectral indices which can compensate for site differences are needed in order to monitor F(sub ipar) more reliably.

Unmanned aerial system nadir reflectance and MODIS nadir BRDF-adjusted surface reflectances intercompared over Greenland

NASA Astrophysics Data System (ADS)

Faulkner Burkhart, John; Kylling, Arve; Schaaf, Crystal B.; Wang, Zhuosen; Bogren, Wiley; Storvold, Rune; Solbø, Stian; Pedersen, Christina A.; Gerland, Sebastian

2017-07-01

Albedo is a fundamental parameter in earth sciences, and many analyses utilize the Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF)/albedo (MCD43) algorithms. While derivative albedo products have been evaluated over Greenland, we present a novel, direct comparison with nadir surface reflectance collected from an unmanned aerial system (UAS). The UAS was flown from Summit, Greenland, on 210 km transects coincident with the MODIS sensor overpass on board the Aqua and Terra satellites on 5 and 6 August 2010. Clear-sky acquisitions were available from the overpasses within 2 h of the UAS flights. The UAS was equipped with upward- and downward-looking spectrometers (300-920 nm) with a spectral resolution of 10 nm, allowing for direct integration into the MODIS bands 1, 3, and 4. The data provide a unique opportunity to directly compare UAS nadir reflectance with the MODIS nadir BRDF-adjusted surface reflectance (NBAR) products. The data show UAS measurements are slightly higher than the MODIS NBARs for all bands but agree within their stated uncertainties. Differences in variability are observed as expected due to different footprints of the platforms. The UAS data demonstrate potentially large sub-pixel variability of MODIS reflectance products and the potential to explore this variability using the UAS as a platform. It is also found that, even at the low elevations flown typically by a UAS, reflectance measurements may be influenced by haze if present at and/or below the flight altitude of the UAS. This impact could explain some differences between data from the two platforms and should be considered in any use of airborne platforms.

Ground truth data for test sites (SL-4). [thermal radiation brightness temperature and solar radiation measurments

NASA Technical Reports Server (NTRS)

1974-01-01

Field measurements performed simultaneous with Skylab overpass in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. Wavelength region covered include: solar radiation (400 to 1300 nanometer), and thermal radiation (8 to 14 micrometer). Measurements consisted of general conditions and near surface meteorology, atmospheric temperature and humidity vs altitude, the thermal brightness temperature, total and diffuse solar radiation, direct solar radiation (subsequently analyzed for optical depth/transmittance), and target reflectivity/radiance. The particular instruments used are discussed along with analyses performed. Detailed instrument operation, calibrations, techniques, and errors are given.

Seasonal vegetation differences from ERTS imagery

NASA Technical Reports Server (NTRS)

Ashley, M. D.; Rea, J.

1975-01-01

Knowledge of the times when crop and forest vegetation experience seasonally related changes in development is important in understanding growth and yield relationships. This article describes how densitometry of earth resources technology satellite (ERTS-1) multispectral scanner (MSS) imagery can be used to identify such phenological events. Adjustments for instrument calibration, aperture size, gray-scale differences between overpasses, and normalization of changing solar elevation are considered in detail. Seasonal vegetation differences can be identified by densitometry of band 5 (0.6-0.7 microns) and band 7 (0.8-1.1 microns) MSS imagery. Band-to-band ratios of the densities depicted the changes more graphically than the individual band readings.

Variability of wetland reflectance and its effect on automatic categorization of satellite imagery

NASA Technical Reports Server (NTRS)

Klemas, V. (Principal Investigator); Bartlett, D.

1977-01-01

The author has identified the following significant results. Land cover categorization of data from the same overpass in four test wetland areas was carried out using a four category classification system. The tests indicate that training data based on in situ reflectance measurements and atmospheric correction of LANDSAT data can produce comparable accuracy of categorization to that achieved using more than four wetlands cover categories (salt marsh cordgrass, salt hay, unvegetated, and water tidal flat) produced overall classification accuracies of 85% by conventional and relative radiance training and 81% by use of in situ measurements. Overall mapping accuracies were 76% and 72% respectively.

Cross-frontal cold jets near Iceland: In-water, satellite infrared, and Geosat altimeter data

NASA Astrophysics Data System (ADS)

Scott, John C.; McDowall, Anne L.

1990-10-01

This paper reports detailed in-water observations and satellite infrared images which are approximately coincident with a single Geosat altimeter track across the Iceland-Faeroes Frontal Zone. The ARE thermistor chain covered the upper 300 m of the ocean along the track, and the first two of a long sequence of NOAA satellite infrared images were obtained, all within 24 hours of the Geosat overpass. The data are interpreted as showing cold cross-frontal jets related to the formation of cold eddies south of the main frontal boundary. Implications for the use of altimetry for ocean monitoring are considered.

The Water Vapor Variability - Satellite/Sondes (WAVES) Field Campaigns

NASA Technical Reports Server (NTRS)

Whiteman, D. N.; Adam, M.; Barnet, C.; Bojkov, B.; Delgado, R.; Demoz, B.; Fitzgibbon, J.; Forno, R.; Herman, R.; Hoff, E.;

Remote sensing operations (multispectral scanner and photographic) in the New York Bight, 22 September 1975

NASA Technical Reports Server (NTRS)

Johnson, R. W.; Hall, J. B., Jr.

1977-01-01

Ocean dumping of waste materials is a significant environmental concern in the New York Bight. One of these waste materials, sewage sludge, was monitored in an experiment conducted in the New York Bight on September 22, 1975. Remote sensing over controlled sewage sludge dumping included an 11-band multispectral scanner, fiver multispectral cameras and one mapping camera. Concurrent in situ water samples were taken and acoustical measurements were made of the sewage sludge plumes. Data were obtained for sewage sludge plumes resulting from line (moving barge) and spot (stationary barge) dumps. Multiple aircraft overpasses were made to evaluate temporal effects on the plume signature.

SR 85 and 77th Special Forces Way West McWhorter Rd Overpass Environmental Assessment

DTIC Science & Technology

2010-06-04

Evaluation criteria were developed and used to evaluate the potential impacts of the interchange alternatives. The evaluation matrix is in a chart...Land Use 6.8 ac taken 17.25 ac taken 34.80 ac taken 27.87 ac taken 35.25 ac taken Safety Stoplight has increased the potential for high speed...change in land  use  in  the easement. The Air Force would conduct further analysis for  potential  land  use  impacts –  Environmental Baseline Study or

Using Roving Cloud Observations from the S'COOL Project to Engage Citizen Scientists

NASA Astrophysics Data System (ADS)

Lewis, P. M.; Oostra, D.; Moore, S. W.; Rogerson, T. M.; Crecelius, S. A.; Chambers, L. H.

2011-12-01

Students' Clouds Observations On-Line (S'COOL) is a hands-on project, which supports NASA research on the Earth's climate. Through their observations, participants are engaged in identifying cloud-types and levels and sending that information to NASA. The two main groups of S'COOL observers are permanent locations such as regularly participating classrooms, and non-permanent locations or Rovers. These non-permanent locations can be a field trip, vacation, or just an occasional observation from a backyard. S'COOL welcomes participation from any interested observers, especially from places where official weather observations are few and far between. This program is offered to citizen scientists all over the world. They are participating in climate research by reporting cloud types and levels within +/- 15 minutes of a satellite overpass and sending that information back to NASA. When a participant's cloud observation coincides with a satellite overpass, the project sends them an email with a MODIS image of the overpass location, and a comparison of the satellite's cloud data results next to their ground-based report. This allows for the students and citizen scientists to participate in ground-truthing the CERES satellite data, to determine the level of agreement/disagreement. A new tool slated for future use in cloud identification, developed by the S'COOL team, is a mobile application. The application is entitled "Cloud Identification for Students" or "CITRUS". The mobile application utilizes a cloud dichotomous key with images to help with cloud identification. Also included in the application is a link to the project's cloud-reporting page to help with data submission in the field. One of the project's recent and most unique roving observers is a solo ocean rower who has traversed many of the world's ocean basins alone in a rowboat. While rowing across the oceans, she has recently been making cloud observations, which she sends back to us for analysis. In doing so, she is contributing difficult-to-collect ground-based data from points over the ocean, where there are typically no human inhabitants. As a result of the cloud reporting, we are able to better validate satellite data that give us a more complete picture of clouds in the atmosphere and their interactions with other parts of the integrated global Earth system. After making the cloud observations, students and citizen scientists are able to analyze the report they get back from NASA, improving their observation/data collection skills while keeping track of cloud patterns as they participate. Through the use of mobile technology, it will be possible to observe and immediately report the observation, allowing for a faster turn around on satellite reports and ground-truth data analysis. This paper will provide an analysis of the non-permanent observations made by the roving observers. These observations will give us an insight to their usefulness, as well as future steps for the program.

Satellite Calibration With LED Detectors at Mud Lake

NASA Technical Reports Server (NTRS)

Hiller, Jonathan D.

2005-01-01

Earth-monitoring instruments in orbit must be routinely calibrated in order to accurately analyze the data obtained. By comparing radiometric measurements taken on the ground in conjunction with a satellite overpass, calibration curves are derived for an orbiting instrument. A permanent, automated facility is planned for Mud Lake, Nevada (a large, homogeneous, dry lakebed) for this purpose. Because some orbiting instruments have low resolution (250 meters per pixel), inexpensive radiometers using LEDs as sensors are being developed to array widely over the lakebed. LEDs are ideal because they are inexpensive, reliable, and sense over a narrow bandwidth. By obtaining and averaging widespread data, errors are reduced and long-term surface changes can be more accurately observed.

Interpretation of surface-water circulation, Aransas Pass, Texas, using Landsat imagery

NASA Technical Reports Server (NTRS)

Finley, R. J.; Baumgardner, R. W., Jr.

1980-01-01

The development of plumes of turbid surface water in the vicinity of Aransas Pass, Texas has been analyzed using Landsat imagery. The shape and extent of plumes present in the Gulf of Mexico is dependent on the wind regime and astronomical tide prior to and at the time of satellite overpass. The best developed plumes are evident when brisk northerly winds resuspend bay-bottom muds and flow through Aransas Pass is increased by wind stress. Seaward diversion of nearshore waters by the inlet jetties was also observed. A knowledge of surface-water circulation through Aransas Pass under various wind conditions is potentially valuable for monitoring suspended and surface pollutants

Consistent Measurement and Physical Character of the DSD: Disdrometer to Satellite

NASA Technical Reports Server (NTRS)

Petersen, Walt; Thurai, Merhala; Gatlin, Patrick; Tokay, Ali; Morris, Bob; Wolff, David; Pippitt, Jason; Marks, David; Berendes, Todd

2017-01-01

Objective: Validate GPM (Global Precipitation Measurement) Drop Size Distribution Retrievals: Drop size distributions (DSD) are critical to GPM DPR (Dual-frequency Precipitation Radar)-based rainfall retrievals; NASA GPM Science Requirements stipulate that the GPM Core observatory radar estimation of D (sub m) (mean diameter) shall be within plus or minus 0.5 millimeters of GV (Ground Validation); GV translates disdrometer measurements to polarimetric radar-based DSD and precipitation type retrievals (e.g., convective vs. stratiform (C/S)) for coincident match-up to GPM core overpasses; How well do we meet the requirement across product versions, rain types (e.g., C/S partitioning), and rain rates (heavy, light) and is behavior physically and internally consistent?

Fire Fighting from High Altitude

NASA Technical Reports Server (NTRS)

Cobleigh, Brent; Ambrosia, Vince

2007-01-01

A viewgraph presentation on high altitude fire fighting is shown. The topics include: 1) Yellowstone Fire - 1988; 2) 2006 Western States Fire Mission Over-View; 3) AMS-Wildfire Scanner; 4) October 24-25 Mission: Yosemite NP and NF; 5) October 24-25 Mission MODIS Overpass; 6) October 24-25 Mission Highlights; 7) October 28-29 Mission Esperanza Fire, California; 8) Response to the Esperanza Fire in Southern California -- Timeline Oct 27-29 2006; 9) October 28-29 Mission Esperanza Fire Altair Flight Routing; 10) October 28-29 Mission Esperanza Fire Altair Over-Flights; 11) October 28-29 Mission Highlights; 12) Results from the Esperanza Fire Response; 13) 2007 Western States Fire Mission; and 14) Western States UAS Fire Mission 2007

The spatial-temporal ambiguity in auroral modeling

NASA Technical Reports Server (NTRS)

Rees, M. H.; Roble, R. G.; Kopp, J.; Abreu, V. J.; Rusch, D. W.; Brace, L. H.; Brinton, H. C.; Hoffman, R. A.; Heelis, R. A.; Kayser, D. C.

1980-01-01

The paper examines the time-dependent models of the aurora which show that various ionospheric parameters respond to the onset of auroral ionization with different time histories. A pass of the Atmosphere Explorer C satellite over Poker Flat, Alaska, and ground based photometric and photographic observations have been used to resolve the time-space ambiguity of a specific auroral event. The density of the O(+), NO(+), O2(+), and N2(+) ions, the electron density, and the electron temperature observed at 280 km altitude in a 50 km wide segment of an auroral arc are predicted by the model if particle precipitation into the region commenced about 11 min prior to the overpass.

The 1990 conterminous U. S. AVHRR data set

USGS Publications Warehouse

Eidenshink, Jeffery C.

1992-01-01

The U.S. Geological Survey, using NOAA-ll Advanced Very High Resolution Radiometer (AVHRR) 1-km data, has produced a time series of 19 biweekly maximum normalized difference vegetation index (NDV!) composites of the conterminous United States for the 1990 growing season. Each biweekly composite included data from approximately 20 calibrated and georegistered daily overpasses. The output is a data set which includes all five calibrated AVHRR channels, NOV! values, three satellite/solar viewing angles, and date of observation pointer for each biweekly composite. The data set is intended for assessing seasonal variations in vegetation condition and provides a foundation for studying long-term changes in vegetation resulting from human interactions or global climate alterations.

Applicability of ERTS-1 imagery to the study of suspended sediment and aquatic fronts

NASA Technical Reports Server (NTRS)

Klemas, V.; Srna, R.; Treasure, W.; Otley, M.

1973-01-01

Imagery from three successful ERTS-1 passes over the Delaware Bay and Atlantic Coastal Region have been evaluated to determine visibility of aquatic features. Data gathered from ground truth teams before and during the overflights, in conjunction with aerial photographs taken at various altitudes, were used to interpret the imagery. The overpasses took place on August 16, October 10, 1972, and January 26, 1973, with cloud cover ranging from about zero to twenty percent. (I.D. Nos. 1024-15073, 1079-15133, and 1187-15140). Visual inspection, density slicing and multispectral analysis of the imagery revealed strong suspended sediment patterns and several distinct types of aquatic interfaces or frontal systems.

A comparative study of infrared radiance measurements by an ER-2 based radiometer and the LANDSAT 5 Thematic Mapper (TM-6)

NASA Technical Reports Server (NTRS)

Hammer, Philip D.; Valero, Francisco P. J.; Kinne, Stefan

1990-01-01

Infrared radiance measurements were acquired from a radiometer on the NASA ER-2 during a coincident LANDSAT 5 overpass on 28 Oct. 1986 as part of the FIRE Cirrus IFO in the vicinity of Lake Michigan. A comparative study is made to infer microphysical properties of the cirrus cloud field. Radiances are derived from the image by convolving the ER-2 radiometer's effective field of view along the flight path. A multistream radiative transfer model is used to account for the differences in spectral bandwidths, 10.40 to 12.50 microns for the LANDSAT band and 9.90 to 10.87 microns for the radiometer.

Surface freezing of water.

PubMed

Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

2016-01-01

Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

Seasat: - JASIN workshop report. Volume 1: Findings and conclusions

NASA Technical Reports Server (NTRS)

1980-01-01

Data acquired from the Joint Air-Sea Interaction (JASIN) Experiment and Seasat data from overpasses that covered the JASIN area were compared and evaluated. The JASIN data were used as a high quality withheld data set. The Seasat data were prepared for each instrument: the Seasat-A Satellite Scatterometer (SASS), the Scanning Multichannel microwave radiometer (SMMR), and the synthetic aperture radar (SAR). The following results demonstrate the performance of Seasat: it was possible to identify mesoscale systems with the SASS as well as fronts; the SMMR provided accurate water vapor content of the atmosphere; the SAR showed evidence of helical rolls in the marine boundary layer; a SASS anomaly could be traced back to thunderstorm activity.

Demographic connectivity for ursid populations at wildlife crossing structures in Banff National Park.

PubMed

Sawaya, Michael A; Clevenger, Anthony P; Kalinowski, Steven T

2013-08-01

Wildlife crossing structures are one solution to mitigating the fragmentation of wildlife populations caused by roads, but their effectiveness in providing connectivity has only been superficially evaluated. Hundreds of grizzly (Ursus arctos) and black bear (Ursus americanus) passages through under and overpasses have been recorded in Banff National Park, Alberta, Canada. However, the ability of crossing structures to allow individual and population-level movements across road networks remains unknown. In April 2006, we initiated a 3-year investigation into whether crossing structures provide demographic connectivity for grizzly and black bears in Banff National Park. We collected hair with multiple noninvasive methods to obtain genetic samples from grizzly and black bears around the Bow Valley. Our objectives were to determine the number of male and female grizzly and black bears that use crossing structures; examine spatial and temporal patterns of crossings; and estimate the proportions of grizzly and black bear populations in the Bow Valley that use crossing structures. Fifteen grizzly (7 female, 8 male) and 17 black bears (8 female, 9 male) used wildlife crossing structures. The number of individuals detected at wildlife crossing structures was highly correlated with the number of passages in space and time. Grizzly bears used open crossing structures (e.g., overpasses) more often than constricted crossings (e.g., culverts). Peak use of crossing structures for both bear species occurred in July, when high rates of foraging activity coincide with mating season. We compared the number of bears that used crossings with estimates of population abundance from a related study and determined that substantial percentages of grizzly (15.0% in 2006, 19.8% in 2008) and black bear (17.6% in 2006, 11.0% in 2008) populations used crossing structures. On the basis of our results, we concluded wildlife crossing structures provide demographic connectivity for bear populations in Banff National Park. © 2013 Society for Conservation Biology.

Mapping the Spectral and Biochemical Characteristics of Riparian Vegetation and Soils

NASA Astrophysics Data System (ADS)

Balaji Bhaskar, M. S.

2016-12-01

Salt cedar (Tamarix ramosissima), an invasive plant species, has successfully invaded large extents of several riparian zones along the western United States and northern Mexico. Mapping the distribution and abundance of Tamarix over these large areas through a, multi-seasonal, cost-effective monitoring approach using satellite remote sensing is very essential. Hence, the objectives of this study are: 1) to identify the spectral characteristics of the major riparian, agricultural vegetation types and soils in the Lower Colorado River (LCR) region; and 2) to determine the biochemical characteristics of the vegetation and soils. Ground truth surveys were conducted at 79 locations where the spectral reflectance measurements of vegetation, type of plant species, plant heights, soil samples and GPS co-ordinates were recorded. All the sampling was designed to coincide with the satellite overpass period. From the LANDSAT TM image, dark-object-subtracted (DOS) digital number (DN) values of six LANDSAT single bands (1-5 and 7) were extracted and all the spectral ratios and vegetative indices were calculated. The NDVI, R1,5 and R1,7 were identified as the best ratios to distinguish the major vegetation types. The LANDSAT TM color-composite spectral ratio image (NDVI, R1,5 and R1,7 as GBR) can clearly identify and map the areas infested with Tamarix. The salt cedar infested riparian soils showed high concentrations of Ca, Mg and Na concentrations compared to other soils and the spectral reflectance of soils with high Na concentrations were significantly higher in the 350-2500 nm spectral range compared to other soils. The Leaf Area Index (LAI) data shows that the salt cedar has higher LAI compared to other riparian vegetation. The spectral and satellite image analysis shows that the selected spectral ratios can be applied to multiple satellite overpasses for monitoring the seasonal progression of the riparian growth over time. Extending the image analysis over wider areas of western United States can improve the understanding of the riparian dynamics in this region.

A comparison between CloudSat and aircraft data for a multilayer, mixed phase cloud system during the Canadian CloudSat-CALIPSO Validation Project

NASA Astrophysics Data System (ADS)

Barker, H. W.; Korolev, A. V.; Hudak, D. R.; Strapp, J. W.; Strawbridge, K. B.; Wolde, M.

2008-04-01

Reflectivities recorded by the W-band Cloud Profiling Radar (CPR) aboard NASA's CloudSat satellite and some of CloudSat's retrieval products are compared to Ka-band radar reflectivities and in situ cloud properties gathered by instrumentation on the NRC's Convair-580 aircraft. On 20 February 2007, the Convair flew several transects along a 60 nautical mile stretch of CloudSat's afternoon ground track over southern Quebec. On one of the transects it was well within CloudSat's radar's footprint while in situ sampling a mixed phase boundary layer cloud. A cirrus cloud was also sampled before and after overpass. Air temperature and humidity profiles from ECMWF reanalyses, as employed in CloudSat's retrieval stream, agree very well with those measured by the Convair. The boundary layer cloud was clearly visible, to the eye and lidar, and dominated the region's solar radiation budget. It was, however, often below or near the Ka-band's distance-dependent minimum detectable signal. In situ samples at overpass revealed it to be composed primarily of small, supercooled droplets at the south end and increasingly intermixed with ice northward. Convair and CloudSat CPR reflectivities for the low cloud agree well, but while CloudSat properly ascribed it as overcast, mixed phase, and mostly liquid near the south end, its estimates of liquid water content LWC (and visible extinction coefficient κ) and droplet effective radii are too small and large, respectively. The cirrus consisted largely of irregular crystals with typical effective radii ˜150 μm. While both CPR reflectivities agree nicely, CloudSat's estimates of crystal number concentrations are too large by a factor of 5. Nevertheless, distributions of ice water content and κ deduced from in situ data agree quite well with values retrieved from CloudSat algorithms.

Multitemporal cross-calibration of the Terra MODIS and Landsat 7 ETM+ reflective solar bands

USGS Publications Warehouse

Angal, Amit; Xiong, Xiaoxiong; Wu, Aisheng; Chander, Gyanesh; Choi, Taeyoung

2013-01-01

In recent years, there has been a significant increase in the use of remotely sensed data to address global issues. With the open data policy, the data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Enhanced Thematic Mapper Plus (ETM+) sensors have become a critical component of numerous applications. These two sensors have been operational for more than a decade, providing a rich archive of multispectral imagery for analysis of mutitemporal remote sensing data. This paper focuses on evaluating the radiometric calibration agreement between MODIS and ETM+ using the near-simultaneous and cloud-free image pairs over an African pseudo-invariant calibration site, Libya 4. To account for the combined uncertainties in the top-of-atmosphere (TOA) reflectance due to surface and atmospheric bidirectional reflectance distribution function (BRDF), a semiempirical BRDF model was adopted to normalize the TOA reflectance to the same illumination and viewing geometry. In addition, the spectra from the Earth Observing-1 (EO-1) Hyperion were used to compute spectral corrections between the corresponding MODIS and ETM+ spectral bands. As EO-1 Hyperion scenes were not available for all MODIS and ETM+ data pairs, MODerate resolution atmospheric TRANsmission (MODTRAN) 5.0 simulations were also used to adjust for differences due to the presence or lack of absorption features in some of the bands. A MODIS split-window algorithm provides the atmospheric water vapor column abundance during the overpasses for the MODTRAN simulations. Additionally, the column atmospheric water vapor content during the overpass was retrieved using the MODIS precipitable water vapor product. After performing these adjustments, the radiometric cross-calibration of the two sensors was consistent to within 7%. Some drifts in the response of the bands are evident, with MODIS band 3 being the largest of about 6% over 10 years, a change that will be corrected in Collection 6 MODIS processing.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khangaonkar, Tarang P.; Breithaupt, Stephen A.; Kristanovich, Felix C.

A hydrodynamic and hydrologic modeling analysis was conducted to evaluate the feasibility of restoring natural estuarine functions and tidal marine wetlands habitat in the Chinook River estuary, located near the mouth of the Columbia River in Washington. The reduction in salmonid populations is attributable primarily to the construction of a Highway 101 overpass across the mouth of the Chinook River in the early 1920s with a tide gate under the overpass. This construction, which was designed to eliminate tidal action in the estuary, has impeded the upstream passage of salmonids. The goal of the Chinook River Restoration Project is tomore » restore tidal functions through the estuary, by removing the tide gate at the mouth of the river, filling drainage ditches, restoring tidal swales, and reforesting riparian areas. The hydrologic model (HEC-HMS) was used to compute Chinook River and tributary inflows for use as input to the hydrodynamic model at the project area boundary. The hydrodynamic model (RMA-10) was used to generate information on water levels, velocities, salinity, and inundation during both normal tides and 100-year storm conditions under existing conditions and under the restoration alternatives. The RMA-10 model was extended well upstream of the normal tidal flats into the watershed domain to correctly simulate flooding and drainage with tidal effects included, using the wetting and drying schemes. The major conclusion of the hydrologic and hydrodynamic modeling study was that restoration of the tidal functions in the Chinook River estuary would be feasible through opening or removal of the tide gate. Implementation of the preferred alternative (removal of the tide gate, restoration of the channel under Hwy 101 to a 200-foot width, and construction of an internal levee inside the project area) would provide the required restorations benefits (inundation, habitat, velocities, and salinity penetration, etc.) and meet flood protection requirements. The alternative design included design of storage such that relatively little difference in the drainage or inundation upstream of Chinook River Valley Road would occur as a result of the proposed restoration activities.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khangaonkar, Tarang P.; Breithaupt, Stephen A.; Kristanovich, Felix C.

A hydrodynamic and hydrologic modeling analysis was conducted to evaluate the feasibility of restoring natural estuarine functions and tidal marine wetlands habitat in the Chinook River estuary, located near the mouth of the Columbia River in Washington. The reduction in salmonid populations is attributable primarily to the construction of a Highway 101 overpass across the mouth of the Chinook River in the early 1920s with a tide gate under the overpass. This construction, which was designed to eliminate tidal action in the estuary, has impeded the upstream passage of salmonids. The goal of the Chinook River Restoration Project is tomore » restore tidal functions through the estuary, by removing the tide gate at the mouth of the river, filling drainage ditches, restoring tidal swales, and reforesting riparian areas. The hydrologic model (HEC-HMS) was used to compute Chinook River and tributary inflows for use as input to the hydrodynamic model at the project area boundary. The hydrodynamic model (RMA-10) was used to generate information on water levels, velocities, salinity, and inundation during both normal tides and 100-year storm conditions under existing conditions and under the restoration alternatives. The RMA-10 model was extended well upstream of the normal tidal flats into the watershed domain to correctly simulate flooding anddrainage with tidal effects included, using the wetting and drying schemes. The major conclusion of the hydrologic and hydrodynamic modeling study was that restoration of the tidal functions in the Chinook River estuary would be feasible through opening or removal of the tide gate. Implementation of the preferred alternative (removal of the tide gate, restoration of the channel under Hwy 101 to a 200-foot width, and construction of an internal levee inside the project area) would provide the required restorations benefits (inundation, habitat, velocities, and salinity penetration, etc.) and meet flood protection requirements. The alternative design included design of storage such that relatively little difference in the drainage or inundation upstream of Chinook River Valley Road would occur as a result of the proposed restoration activities.« less

Daytime variation of aerosol optical depth in North China and its impact on aerosol direct radiative effects

NASA Astrophysics Data System (ADS)

Song, Jingjing; Xia, Xiangao; Che, Huizheng; Wang, Jun; Zhang, Xiaoling; Li, Xiaojing

2018-06-01

Daytime cycles of aerosol optical depth (AOD) and Angstrom exponent (AE) climatology were analyzed based on long-term (5-15 years) measurements at 18 stations of the China Aerosol Remote Sensing Network (CARSNET) in North China. AOD in Northwest China (NWC) exhibits a daytime trend with negative departures in the early morning and later afternoon while positive departures at midday. Daytime AOD relative departure in different sites and seasons varies from -30.26% to 30.28%. AE in NWC shows an opposite pattern to daytime variation of AOD. Daytime variation of AE is negligible in North China Plain (NCP), AOD increases steadily throughout the day. This trend is consistent and repeatable in four seasons. Such pronounced variability in AOD and AE should be taken accounted for in the estimation of diurnal aerosol direct radiative effects (ADRE), as suggested by the radiative transfer model simulations. The replacement of the observed daytime variation of AOD and AE by daytime mean values in NWC results in ADRE differences of 0.31 Wm-2 at the surface and 0.05 Wm-2 at the top of the atmosphere (TOA). ADRE in NWC will be underestimated by -0.47 Wm-2 and -0.25 Wm-2 at the surface and TOA, respectively, if instantaneous AOD and AE during the overpass time of Terra and Aqua are taken as the daytime mean values. The annual mean ADRE at the surface and TOA will be underestimated by -0.17 Wm-2 and -0.03 Wm-2 if daytime variations of AOD and AE are replaced by daytime mean values in NCP. ADRE will be underestimated by -0.07 Wm-2 at the surface and -0.06 Wm-2 at the TOA if instantaneous AOD and AE during the overpass time of Terra and Aqua other than daytime variation of AOD and AE are used in the calculations.

Assessment of the relationship between chlorophyll fluorescence and photosynthesis across scales from measurements and simulations

NASA Astrophysics Data System (ADS)

Zhang, Y.; Guanter, L.; Berry, J. A.; Tol, C. V. D.

2016-12-01

Solar-induced chlorophyll fluorescence (SIF) is a novel optical tool for assessment of terrestrial photosynthesis (GPP). Recent work have shown the strong link between GPP and satellite retrievals of SIF at broad scales. However, critical gaps remain between short term small-scale mechanistic understanding and seasonal global observations. In this presentation, we provide a model-based analysis of the relationship between SIF and GPP across scales for diverse vegetation types and a range of meteorological conditions, with the ultimate focus on reproducing the environmental conditions during remote sensing measurements. The coupled fluorescence-photosynthesis model SCOPE is used to simulate GPP and SIF at the both leaf and canopy levels for 13 flux sites. Analyses were conducted to investigate the effects of temporal scaling, canopy structure, overpass time, and spectral domain on the relationship between SIF and GPP. The simulated SIF is highly non-linear with GPP at the leaf level and instantaneous time scale and tends to linearize when scaling to the canopy level and daily to seasonal scales. These relationships are consistent across a wide range of vegetation types. The relationship between SIF and GPP is primarily driven by absorbed photosynthetically active radiation (APAR), especially at the seasonal scale, although the photosynthetic efficiency also contributes to strengthen the link between them. The linearization of their relationship from leaf to canopy and averaging over time is because the overall conditions of the canopy fall within the range of the linear responses of GPP and SIF to light and the photosynthetic capacity. Our results further show that the top-of-canopy relationships between simulated SIF and GPP have similar linearity regardless of whether we used the morning or midday satellite overpass times. These findings are confirmed by field measurements. In addition, the simulated red SIF at 685 nm has a similar relationship with GPP as that of far-red SIF at 740 nm at the canopy level.

Multitemporal Cross-Calibration of the Terra MODIS and Landsat 7 ETM+ Reflective Solar Bands

NASA Technical Reports Server (NTRS)

Angal, Amit; Xiong, Xiaoxiong; Wu, Aisheng; Changler, Gyanesh; Choi, Taeyoyung

2013-01-01

In recent years, there has been a significant increase in the use of remotely sensed data to address global issues. With the open data policy, the data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Enhanced Thematic Mapper Plus (ETM+) sensors have become a critical component of numerous applications. These two sensors have been operational for more than a decade, providing a rich archive of multispectral imagery for analysis of mutitemporal remote sensing data. This paper focuses on evaluating the radiometric calibration agreement between MODIS and ETM+ using the near-simultaneous and cloud-free image pairs over an African pseudo-invariant calibration site, Libya 4. To account for the combined uncertainties in the top-of-atmosphere (TOA) reflectance due to surface and atmospheric bidirectional reflectance distribution function (BRDF), a semiempirical BRDF model was adopted to normalize the TOA reflectance to the same illumination and viewing geometry. In addition, the spectra from the Earth Observing-1 (EO-1) Hyperion were used to compute spectral corrections between the corresponding MODIS and ETM+ spectral bands. As EO-1 Hyperion scenes were not available for all MODIS and ETM+ data pairs, MODerate resolution atmospheric TRANsmission (MODTRAN) 5.0 simulations were also used to adjust for differences due to the presence or lack of absorption features in some of the bands. A MODIS split-window algorithm provides the atmospheric water vapor column abundance during the overpasses for the MODTRAN simulations. Additionally, the column atmospheric water vapor content during the overpass was retrieved using the MODIS precipitable water vapor product. After performing these adjustments, the radiometric cross-calibration of the two sensors was consistent to within 7%. Some drifts in the response of the bands are evident, with MODIS band 3 being the largest of about 6% over 10 years, a change that will be corrected in Collection 6 MODIS processing.

Near Real Time MISR Wind Observations for Numerical Weather Prediction

NASA Astrophysics Data System (ADS)

Mueller, K. J.; Protack, S.; Rheingans, B. E.; Hansen, E. G.; Jovanovic, V. M.; Baker, N.; Liu, J.; Val, S.

2014-12-01

The Multi-angle Imaging SpectroRadiometer (MISR) project, in association with the NASA Langley Atmospheric Science Data Center (ASDC), has this year adapted its original production software to generate near-real time (NRT) cloud-motion winds as well as radiance imagery from all nine MISR cameras. These products are made publicly available at the ASDC with a latency of less than 3 hours. Launched aboard the sun-synchronous Terra platform in 1999, the MISR instrument continues to acquire near-global, 275 m resolution, multi-angle imagery. During a single 7 minute overpass of any given area, MISR retrieves the stereoscopic height and horizontal motion of clouds from the multi-angle data, yielding meso-scale near-instantaneous wind vectors. The ongoing 15-year record of MISR height-resolved winds at 17.6 km resolution has been validated against independent data sources. Low-level winds dominate the sampling, and agree to within ±3 ms-1 of collocated GOES and other observations. Low-level wind observations are of particular interest to weather forecasting, where there is a dearth of observations suitable for assimilation, in part due to reliability concerns associated with winds whose heights are assigned by the infrared brightness temperature technique. MISR cloud heights, on the other hand, are generated from stereophotogrammetric pattern matching of visible radiances. MISR winds also address data gaps in the latitude bands between geostationary satellite coverage and polar orbiting instruments that obtain winds from multiple overpasses (e.g. MODIS). Observational impact studies conducted by the Naval Research Laboratory (NRL) and by the German Weather Service (Deutscher Wetterdienst) have both demonstrated forecast improvements when assimilating MISR winds. An impact assessment using the GEOS-5 system is currently in progress. To benefit air quality forecasts, the MISR project is currently investigating the feasibility of generating near-real time aerosol products.

DisPATCh as a tool to evaluate coarse-scale remotely sensed soil moisture using localized in situ measurements: Application to SMOS and AMSR-E data in Southeastern Australia

NASA Astrophysics Data System (ADS)

Malbéteau, Yoann; Merlin, Olivier; Molero, Beatriz; Rüdiger, Christoph; Bacon, Stephan

2016-03-01

Validating coarse-scale satellite soil moisture data still represents a big challenge, notably due to the large mismatch existing between the spatial resolution (> 10 km) of microwave radiometers and the representativeness scale (several m) of localized in situ measurements. This study aims to examine the potential of DisPATCh (Disaggregation based on Physical and Theoretical scale Change) for validating SMOS (Soil Moisture and Ocean Salinity) and AMSR-E (Advanced Microwave Scanning Radiometer-Earth observation system) level-3 soil moisture products. The ∽40-50 km resolution SMOS and AMSR-E data are disaggregated at 1 km resolution over the Murrumbidgee catchment in Southeastern Australia during a one year period in 2010-2011, and the satellite products are compared with the in situ measurements of 38 stations distributed within the study area. It is found that disaggregation improves the mean difference, correlation coefficient and slope of the linear regression between satellite and in situ data in 77%, 92% and 94% of cases, respectively. Nevertheless, the downscaling efficiency is lower in winter than during the hotter months when DisPATCh performance is optimal. Consistently, better results are obtained in the semi-arid than in a temperate zone of the catchment. In the semi-arid Yanco region, disaggregation in summer increases the correlation coefficient from 0.63 to 0.78 and from 0.42 to 0.71 for SMOS and AMSR-E in morning overpasses and from 0.37 to 0.63 and from 0.47 to 0.73 for SMOS and AMSR-E in afternoon overpasses, respectively. DisPATCh has strong potential in low vegetated semi-arid areas where it can be used as a tool to evaluate coarse-scale remotely sensed soil moisture by explicitly representing the sub-pixel variability.

FIRE extended time/limited area observations at Palisades, New York

NASA Technical Reports Server (NTRS)

Robinson, David A.; Kukla, George; Frei, Alan

1990-01-01

Downwelling shortwave and longwave irradiation are being continuously monitored at Palisades, New York as part of the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE) Extended Time/Limited Area Initiative. In addition, fisheye (180 degree) sky photographs are taken at the times of NOAA 9 and LANDSAT satellite overpasses on select days, particularly when cirrus clouds are present. Measurements of incoming shortwave (0.28 to 2.80 microns) hemispheric and diffuse, hemispheric near infrared (0.7 to 2.80 microns), and downwelling hemispheric infrared (4.0 to 50.0 microns) irradiation have been made from a rooftop location on the grounds of the Lamont-Doherty Geological Observatory since December 1986. The three Eppley Precision Spectral Pyranometers and the Eppley Pyrgeometer used to measure these variables were calibrated with Colorado State University instruments at Madison, Wisconsin as part of the FIRE Intensive Laboratory. Pyrgeometer output contains an adjustment for body temperature but not for dome temperature. Data are transmitted to a Campbell CR-21 Digital Recorder, where one minute averages of ten second samples are stored and subsequently dumped to a cassette recorder. Using a Campbell C-20 Cassette Interface, these data are transferred to an Apple Macintosh computer for analysis and for archiving on floppy disks. In addition to the raw irradiances collected, variables derived from these data are generated and stored. These include: the ratio of near infrared irradiation to visible irradiation and the fraction of the full shortwave irradiation which is diffuse; and will soon include: shortwave transmissivity and optical depth in the shortwave. Sky photographs are taken with an Olympus OM2-N 35 mm camera and are timed to be coincident with overpassing NOAA and LANDSAT satellites. Palisades is within the field of view of the NOAA 9 daily in the middle to late afternoon. The satellite viewing angle is within 45 degrees of nadir over Palisades on approximately half of the passes.

Space-Based Remote Imaging Spectroscopy of the Aliso Canyon CH4 Superemitter

NASA Technical Reports Server (NTRS)

Thompson, D. R.; Thorpe, A. K.; Frankenberg, C.; Green, R. O.; Duren, R.; Guanter, L.; Hollstein, A.; Middleton, E.; Ong, L.; Ungar, S.

2016-01-01

The Aliso Canyon gas storage facility near Porter Ranch, California, produced a large accidental CH4 release from October 2015 to February 2016. The Hyperion imaging spectrometer on board the EO-1 satellite successfully detected this event, achieving the first orbital attribution of CH4 to a single anthropogenic superemitter. Hyperion measured shortwave infrared signatures of CH4 near 2.3 microns at 0.01 micron spectral resolution and 30 meter spatial resolution. It detected the plume on three overpasses, mapping its magnitude and morphology. These orbital observations were consistent with measurements by airborne instruments. We evaluate Hyperion instrument performance, draw implications for future orbital instruments, and extrapolate the potential for a global survey of CH4 superemitters.

Observing the Earth from Afar with NASA's Worldview

NASA Technical Reports Server (NTRS)

Wong, Min Minnie; Boller, Ryan; Baynes, Kathleen; King, Benjamin; Rice, Zachary

2017-01-01

NASA's Worldview interactive web map application delivers global, near real-time imagery from NASA's fleet of Earth Observing System (EOS) satellites. Within hours of satellite overpass, discover where the latest wildfires, severe storms, volcanic eruptions, dust and haze, ice shelves calving as well as many other events are occurring around the world. Near real-time imagery is made available in Worldview through the Land, Atmosphere Near real-time Capability for EOS (LANCE) via the Global Imagery Browse Services (GIBS). This poster will explore new near real-time imagery available in Worldview, the current ways in which the imagery is used in research, the news and social media and future improvements to Worldview that will enhance the availability and viewing of NASA EOS imagery.

Zones of coastal hypoxia revealed by satellite scanning have implications for strategic fishing

NASA Technical Reports Server (NTRS)

Leming, T. D.; Stuntz, W. E.

1984-01-01

Little is known about the spatial and temporal scales of hypoxic bottom water areas that occur along the inner continental shelf of Texas and Louisiana. Because hypoxia appears to be related to surface chlorophyll and temperature, which can both be measured with the Coastal Zone Color Scanner aboard the Nimbus 7 satellite, an attempt has been made to determine whether conditions favorable for the formation of hypoxia could be detected and monitored from space. A linear discriminant function has identified areas of bottom water hypoxia detected by research vessels up to 10 days after satellite overpass, and predicted hypoxic areas without resort to research vessel data. Such space mapping may be of consequence for marine resource management and exploitation.

Observing the Earth from afar with NASA's Worldview

NASA Astrophysics Data System (ADS)

Wong, M. M.; Boller, R. A.; King, B. A.; Baynes, K.; Rice, Z.

2017-12-01

NASA's Worldview interactive web map application delivers global, near real-time imagery from NASA's fleet of Earth Observing System (EOS) satellites. Within hours of satellite overpass, discover where the latest wildfires, severe storms, volcanic eruptions, dust and haze, ice shelves calving as well as many other events are occurring around the world. Near real-time imagery is made available in Worldview through the Land Atmosphere Near real-time Capability for EOS (LANCE) via the Global Imagery Browse Services (GIBS). This poster will explore new near real-time imagery available in Worldview, the current ways in which the imagery is used in research, the news and social media and future improvements to Worldview that will enhance the availability and viewing of NASA EOS imagery.

Bigfoot Field Manual

NASA Astrophysics Data System (ADS)

Campbell, J. L.; Burrows, S.; Gower, S. T.; Cohen, W. B.

1999-09-01

The BigFoot Project is funded by the Earth Science Enterprise to collect and organize data to be used in the EOS Validation Program. The data collected by the BigFoot Project are unique in being ground-based observations coincident with satellite overpasses. In addition to collecting data, the BigFoot project will develop and test new algorithms for scaling point measurements to the same spatial scales as the EOS satellite products. This BigFoot Field Manual Mill be used to achieve completeness and consistency of data collected at four initial BigFoot sites and at future sites that may collect similar validation data. Therefore, validation datasets submitted to the ORNL DAAC that have been compiled in a manner consistent with the field manual will be especially valuable in the validation program.

Surface Temperature Assimilation in Land Surface Models

NASA Technical Reports Server (NTRS)

Lakshmi, Venkataraman

1997-01-01

This paper examines the utilization of surface temperature as a variable to be assimilated in offline land surface hydrological models. Comparisons between the model computed and satellite observed surface temperatures have been carried out. The assimilation of surface temperature is carried out twice a day (corresponding to the AM and PM overpass of the NOAA10) over the Red- Arkansas basin in the Southwestern United States (31 deg 50 min N - 36 deg N, 94 deg 30 min W - 104 deg 30 min W) for a period of one year (August 1987 to July 1988). The effect of assimilation is to reduce the difference between the surface soil moisture computed for the precipitation and/or shortwave radiation perturbed case and the unperturbed case compared to no assimilation.

Surface Temperature Assimilation in Land Surface Models

NASA Technical Reports Server (NTRS)

Lakshmi, Venkataraman

1999-01-01

This paper examines the utilization of surface temperature as a variable to be assimilated in offline land surface hydrological models. Comparisons between the model computed and satellite observed surface temperatures have been carried out. The assimilation of surface temperature is carried out twice a day (corresponding to the AM and PM overpass of the NOAA10) over the Red-Arkansas basin in the Southwestern United States (31 degs 50 sec N - 36 degrees N, 94 degrees 30 seconds W - 104 degrees 3 seconds W) for a period of one year (August 1987 to July 1988). The effect of assimilation is to reduce the difference between the surface soil moisture computed for the precipitation and/or shortwave radiation perturbed case and the unperturbed case compared to no assimilation.

Let Our Powers Combine! Harnessing NASA's Earth Observatory Natural Event Tracker (EONET) in Worldview

NASA Technical Reports Server (NTRS)

Wong, Min Minnie; Ward, Kevin; Boller, Ryan; Gunnoe, Taylor; Baynes, Kathleen; King, Benjamin

2016-01-01

Constellations of NASA Earth Observing System (EOS) satellites orbit the earth to collect images and data about the planet in near real-time. Within hours of satellite overpass, you can discover where the latest wildfires, severe storms, volcanic eruptions, and dust and haze events are occurring using NASA's Worldview web application. By harnessing a repository of curated natural event metadata from NASA Earth Observatory's Natural Event Tracker (EONET), Worldview has moved natural event discovery to the forefront and allows users to select events-of-interest from a curated list, zooms to the area, and adds the most relevant imagery layers for that type of natural event. This poster will highlight NASA Worldviews new natural event feed functionality.

Evaluation of ERTS MSS digital data for monitoring water in the lower Chesapeake Bay area

NASA Technical Reports Server (NTRS)

Bowker, D. E.; Witte, W. G.

1975-01-01

Water samples collected during the ERTS overpasses of the lower Chesapeake Bay area have been analyzed for chlorophyll, particles, and sediment. Five ERTS images were sufficiently cloud free that a correlation analysis of radiance values from the MSS bands with the water parameters could be performed. A low correlation was established for chlorophyll, except during algal blooms, when band 6 was responsive. There was a fair to good correlation with particles for combinations of band 5, particularly bands (5 minus 6). Sediment correlations were excellent for band 5 or combinations of band 5 with bands 4 and 6. It was evident that such factors as the atmosphere, tide, and different water masses were tending to confuse the data.

Ground truth data for test sites (SL-3). [solar radiation and thermal radiation brightness temperature measurements

NASA Technical Reports Server (NTRS)

1974-01-01

Field measurements performed simultaneously with Skylab overpasses in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. The solar radiation region from 400 to 1300 nanometers and the thermal radiation region from 8 to 14 micrometer region were investigated. The measurements of direct solar radiation were analyzed for atmospheric optical depth; the total and reflected solar radiation were analyzed for target reflectivity. These analyses were used in conjunction with a radiative transfer computer program in order to calculate the amount and spectral distribution of solar radiation at the apertures of the EREP sensors. The instrumentation and techniques employed, calibrations and analyses performed, and results obtained are discussed.

Evaluation of solar angle variation over digital processing of LANDSAT imagery. [Brazil

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Novo, E. M. L. M.

1984-01-01

The effects of the seasonal variation of illumination over digital processing of LANDSAT images are evaluated. Original images are transformed by means of digital filtering to enhance their spatial features. The resulting images are used to obtain an unsupervised classification of relief units. After defining relief classes, which are supposed to be spectrally different, topographic variables (declivity, altitude, relief range and slope length) are used to identify the true relief units existing on the ground. The samples are also clustered by means of an unsupervised classification option. The results obtained for each LANDSAT overpass are compared. Digital processing is highly affected by illumination geometry. There is no correspondence between relief units as defined by spectral features and those resulting from topographic features.

UARS MILS O3 soundings compared with lidar measurements using the conservative coordinates reconstruction technique

NASA Technical Reports Server (NTRS)

Redaelli, G.; Lait, L. R.; Schoeberl, M.; Newman, P. A.; Visconti, G.; D'Altorio, A.; Masci, F.; Rizi, V.; Froidevaux, L.; Waters, J. W.

1994-01-01

A technique based on conservative properties of certain meteorological fields is used to compare ozone measurements from the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) with soundings from a lidar system operated at midlatitudes by the University of L'Aquila, Italy. A few typical cases are analyzed in connection with the position of the vortex relative to the observing station, and it is shown that in general lidar observations taken within the vortex compare well with the UARS data, regardless of whether they are coincident with a satellite overpass. It is shown that such analysis may be useful for comparing measurements of the same quantity taken at different sites using different measurement techniques.

Towards Validation of SMAP: SMAPEX-4 & -5

NASA Technical Reports Server (NTRS)

Ye, Nan; Walker, Jeffrey; Wu, Xiaoling; Jackson, Thomas; Renzullo, Luigi; Merlin, Olivier; Rudiger, Christoph; Entekhabi, Dara; DeJeu, Richard; Kim, Edward

2016-01-01

The L-band (1 - 2 GHz) microwave remote sensing has been widely acknowledged as the most promising method to monitor regional to global soil moisture. Consequently, the Soil Moisture Active Passive (SMAP) satellite applied this technique to provide global soil moisture every 2 to 3 days. To verify the performance of SMAP, the fourth and fifth campaign of SMAP Experiments (SMAPEx-4 -5) were carried out at the beginning of the SMAP operational phase in the Murrumbidgee River catchment, southeast Australia. The airborne radar and radiometer observations together with ground sampling on soil moisture, vegetation water content, and surface roughness were collected in coincidence with SMAP overpasses. The SMAPEx-4 and -5 data sets will benefit to SMAP post-launch calibration andvalidation under Australian land surface conditions.

Soil, water, and vegetation conditions in South Texas

NASA Technical Reports Server (NTRS)

Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J.; Everitt, J. H.; Gerbermann, A. H. (Principal Investigator)

1976-01-01

The author has identified the following significant results. Reflectance measurements with a field spectroradiometer on nine dates (between December 9 and April 8) during the growing season of two wheat varieties, Milam and Penjamo, showed that the reflectance curves had the characteristic shape of vegetated surfaces by 4 weeks after the emergence. Green light (0.55 micron) reflectance was maximal and between water absorption bands (1.65 and 2.2 microns) reflectance was minimal when green vegetation development was greatest. Computer classification was accomplished for 81,000 hectare coastal rangeland area for October 13 and December 10, 1975, overpass dates. A hard freeze occurred between these two dates and many of the deciduous woody species defoliated so that more light penetrated to the herbaceous understory in December than in October.

Passive microwave (SSM/I) satellite predictions of valley glacier hydrology, Matanuska Glacier, Alaska

USGS Publications Warehouse

Kopczynski, S.E.; Ramage, J.; Lawson, D.; Goetz, S.; Evenson, E.; Denner, J.; Larson, G.

2008-01-01

We advance an approach to use satellite passive microwave observations to track valley glacier snowmelt and predict timing of spring snowmelt-induced floods at the terminus. Using 37 V GHz brightness temperatures (Tb) from the Special Sensor Microwave hnager (SSM/I), we monitor snowmelt onset when both Tb and the difference between the ascending and descending overpasses exceed fixed thresholds established for Matanuska Glacier. Melt is confirmed by ground-measured air temperature and snow-wetness, while glacier hydrologic responses are monitored by a stream gauge, suspended-sediment sensors and terminus ice velocity measurements. Accumulation area snowmelt timing is correlated (R2 = 0.61) to timing of the annual snowmelt flood peak and can be predicted within ??5 days. Copyright 2008 by the American Geophysical Union.

Dryland pasture and crop conditions as seen by HCMM. [Washita River watershed

NASA Technical Reports Server (NTRS)

Harlan, J. C. (Principal Investigator); Rosenthal, W. D.; Blanchard, B. J.

1981-01-01

The antecedent precipitation index (API) was related to surface temperatures as measured from the NASA C-130 and HCMM thermal data. Significant results from the aircraft flight in May 1978, include: (1) canopy temperature were measured accurately remotely; (2) pasture surface temperatures were related to pasture and wheat soil moisture conditions; (3) no relationship was developed with that data set between wheat yield and thermal infrared data due to a lack of moisture stress during the measurement period; and (4) lake surface temperatures were useful in normalizing the thermal IR data. Results from HCMM also suggested a relationship between thermal IR data and antecedent precipitation index. While HCMM was adequate in detecting relative soil moisture differences, the overpass timing was infrequent and prevented detailed analysis of the API/thermal relationship.

Skylab program earth resources experiment package: Ground truth data for test sites (SL-2)

NASA Technical Reports Server (NTRS)

1975-01-01

Field measurements were performed at selected ground sites in order to provide comparative calibration measurements of sensors for the Earth Resources Experiment Package. Specifically, the solar radiation (400 to 1300 namometers) and thermal radiation (8-14 micrometers) were measured. Sites employed for the thermal measurements consisted of warm and cold water lakes. The thermal brightness temperature of the lake water, the temperature and humidity profile above the lake, and near surface meteorology (wind speed, pressure, etc.) were measured near the time of overpass. Sites employed for the solar radiation measurements were two desert type sites. Ground measurements consisted of: (1) direct solar radiation - optical depth; (2) diffuse solar radiation; (3) total solar radiation, (4) target directional (normal) reflectance; (5) target hemispherical reflectance; and (6) near surface meteorology.

Comparison of spectral ultraviolet irradiance measured from satellite and ground-based instrument at Nakhon Pathom province

NASA Astrophysics Data System (ADS)

Sriwongsa, J.; Buntoung, S.

2017-09-01

In this study, comparisons of spectral ultraviolet irradiance at 305, 310, 324 and 380 nm at the overpass time retrieved from OMI/AURA satellite with that from ground-based measurements were performed at Nakhon Pathom (13.82°N,100.04°E), Thailand. The analyzed data period comprised from 1 January 2010 to 31 December 2015. The comparison results clearly showed the overestimation of satellite data with root mean square difference (RMSD) between 22.9 and 48.9%, and mean bias difference (MBD) between 5.3 and 39.8% for all sky conditions, and reduced to 10.6-40.5% and 0.18-34.9% for clear sky conditions. Further results showed that the differences between the two datasets depend on atmospheric aerosol loads and clouds.

Influence of Observed Diurnal Cycles of Aerosol Optical Depth on Aerosol Direct Radiative Effect

NASA Technical Reports Server (NTRS)

Arola, A.; Eck, T. F.; Huttunen, J.; Lehtinen, K. E. J.; Lindfors, A. V.; Myhre, G.; Smirinov, A.; Tripathi, S. N.; Yu, H.

2013-01-01

The diurnal variability of aerosol optical depth (AOD) can be significant, depending on location and dominant aerosol type. However, these diurnal cycles have rarely been taken into account in measurement-based estimates of aerosol direct radiative forcing (ADRF) or aerosol direct radiative effect (ADRE). The objective of our study was to estimate the influence of diurnal aerosol variability at the top of the atmosphere ADRE estimates. By including all the possible AERONET sites, we wanted to assess the influence on global ADRE estimates. While focusing also in more detail on some selected sites of strongest impact, our goal was to also see the possible impact regionally.We calculated ADRE with different assumptions about the daily AOD variability: taking the observed daily AOD cycle into account and assuming diurnally constant AOD. Moreover, we estimated the corresponding differences in ADREs, if the single AOD value for the daily mean was taken from the the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra or Aqua overpass times, instead of accounting for the true observed daily variability. The mean impact of diurnal AOD variability on 24 h ADRE estimates, averaged over all AERONET sites, was rather small and it was relatively small even for the cases when AOD was chosen to correspond to the Terra or Aqua overpass time. This was true on average over all AERONET sites, while clearly there can be much stronger impact in individual sites. Examples of some selected sites demonstrated that the strongest observed AOD variability (the strongest morning afternoon contrast) does not typically result in a significant impact on 24 h ADRE. In those cases, the morning and afternoon AOD patterns are opposite and thus the impact on 24 h ADRE, when integrated over all solar zenith angles, is reduced. The most significant effect on daily ADRE was induced by AOD cycles with either maximum or minimum AOD close to local noon. In these cases, the impact on 24 h ADRE was typically around 0.1-0.2W/sq m (both positive and negative) in absolute values, 5-10% in relative ones.

A Well-Calibrated Ocean Algorithm for Special Sensor Microwave/Imager

NASA Technical Reports Server (NTRS)

Wentz, Frank J.

1997-01-01

I describe an algorithm for retrieving geophysical parameters over the ocean from special sensor microwave/imager (SSM/I) observations. This algorithm is based on a model for the brightness temperature T(sub B) of the ocean and intervening atmosphere. The retrieved parameters are the near-surface wind speed W, the columnar water vapor V, the columnar cloud liquid water L, and the line-of-sight wind W(sub LS). I restrict my analysis to ocean scenes free of rain, and when the algorithm detects rain, the retrievals are discarded. The model and algorithm are precisely calibrated using a very large in situ database containing 37,650 SSM/I overpasses of buoys and 35,108 overpasses of radiosonde sites. A detailed error analysis indicates that the T(sub B) model rms accuracy is between 0.5 and 1 K and that the rms retrieval accuracies for wind, vapor, and cloud are 0.9 m/s, 1.2 mm, and 0.025 mm, respectively. The error in specifying the cloud temperature will introduce an additional 10% error in the cloud water retrieval. The spatial resolution for these accuracies is 50 km. The systematic errors in the retrievals are smaller than the rms errors, being about 0.3 m/s, 0.6 mm, and 0.005 mm for W, V, and L, respectively. The one exception is the systematic error in wind speed of -1.0 m/s that occurs for observations within +/-20 deg of upwind. The inclusion of the line-of-sight wind W(sub LS) in the retrieval significantly reduces the error in wind speed due to wind direction variations. The wind error for upwind observations is reduced from -3.0 to -1.0 m/s. Finally, I find a small signal in the 19-GHz, horizontal polarization (h(sub pol) T(sub B) residual DeltaT(sub BH) that is related to the effective air pressure of the water vapor profile. This information may be of some use in specifying the vertical distribution of water vapor.

Subvisual-thin cirrus lidar dataset for satellite verification and climatological research

NASA Technical Reports Server (NTRS)

Sassen, Kenneth; Cho, Byung S.

1992-01-01

A polarization (0.694 microns wavelength) lidar dataset for subvisual and thin (bluish-colored) cirrus clouds is drawn from project FIRE (First ISCCP Regional Experiment) extended time observations. The clouds are characterized by their day-night visual appearance; base, top, and optical midcloud heights and temperatures; measured physical and estimated optical cloud thicknesses; integrated linear depolarization ratios; and derived k/2 eta ratios. A subset of the data supporting 30 NOAA polar-orbiting satellite overpasses is given in tabular form to provide investigators with the means to test cloud retrieval algorithms and establish the limits of cirrus detectability from satellite measurements under various conditions. Climatologically, subvisual-thin cirrus appear to be higher, colder, and more strongly depolarizing than previously reported multilatitude cirrus, although similar k/2 eta that decrease with height and temperature are found.

First aircraft test results of a compact, low cost hyperspectral imager for earth observation from space

NASA Astrophysics Data System (ADS)

de Goeij, B. T. G.; Otter, G. C. J.; van Wakeren, J. M. O.; Veefkind, J. P.; Vlemmix, T.; Ge, X.; Levelt, P. F.; Dirks, B. P. F.; Toet, P. M.; van der Wal, L. F.; Jansen, R.

2017-09-01

In recent years TNO has investigated and developed different innovative opto-mechanical designs to realize advanced spectrometers for space applications in a more compact and cost-effective manner. This offers multiple advantages: a compact instrument can be flown on a much smaller platform or as add-on on a larger platform; a low-cost instrument opens up the possibility to fly multiple instruments in a satellite constellation, improving both global coverage and temporal sampling (e.g. multiple overpasses per day to study diurnal processes); in this way a constellation of low-cost instruments may provide added value to the larger scientific and operational satellite missions (e.g. the Copernicus Sentinel missions); a small, lightweight spectrometer can easily be mounted on a small aircraft or high-altitude UAV (offering high spatial resolution).

Characterization of AIRS temperature and water vapor measurement capability using correlative observations

NASA Technical Reports Server (NTRS)

Fetzer, Eric J.; Eldering, Annmarie; Lee, Sung-Yung

2005-01-01

In this presentation we address several fundamental issues in the measurement of temperature and water vapor by AIRS: accuracy, precision, vertical resolution and biases as a function of cloud amount. We use two correlative data sources. First we compare AIRS total water vapor with that from the Advanced microwave Sounding Radiometer for EOS (AMSR-E) instrument, also onboard the Aqua spacecraft. AMSRE uses a mature methodology with a heritage including the operational Special Sensor Microwave Imager (SSM/I) instruments. AIRS and AMSR-E observations are collocated and simultaneous, providing a very large data set for comparison: about 200,000 over-ocean matches daily. We show small cloud-dependent biases between AIRS and AMSR-E total water vapor for several oceanic regions. Our second correlative data source is several hundred dedicated radiosondes launched during AIRS overpasses.

Summary of water- and sediment-quality data for Anacostia River well sites sampled in July-August 2002

USGS Publications Warehouse

Miller, Cherie V.; Klohe, Cheryl A.

2003-01-01

This data report is a summary of chemical analyses conducted by the U.S. Geological Survey on ground water and sediment in the tidal Anacostia River watershed, Washington, D.C. during July-August 2002. Cores were drilled and wells were established at three shoreline sites: two wells at the New York Avenue overpass, two wells at the Kenilworth Aquatic Gardens, and one well at Anacostia Park. Additionally, two cores were collected by hoverprobe in mudflats on the river: one by Benning Road and one in the mouth of Beaverdam Creek. Chemical analyses included volatile organic compounds, semi-volatile organic compounds or polyaromatic hydrocarbons, organochlorine pesticides, aroclors and total polychlorinated biphenyls, metals, nutrients, biochemical and chemical oxygen demands, total phenols, total cyanide, oil and grease, and total suspended and dissolved solids in aqueous phases.

Analysis of direct solar ultraviolet irradiance measurements in the French Alps. Retrieval of turbidity and ozone column amount.

PubMed

Lenoble, Jacqueline; de la Casinière, Alain; Cabot, Thierry

2004-05-20

Direct ultraviolet spectral solar irradiance is regularly obtained by the difference between global and diffuse irradiances at the French Alpine station of Briançon; the data of years 2001 and 2002 are analyzed in this paper. Comparison with modeled values is used for cloud screening, and an average UV-A aerosol optical depth is used as an index of turbidity; it is found to be around 0.05 for the clear winter days and around 0.2 in summer. Langley plots are used to verify the instrument calibration; they confirm the expected uncertainty smaller than 5%. The ozone total column amount is estimated with an uncertainty between -3 and Dobson units; comparisons with TOMS (Total Ozone Mapping Spectrometer) overpass values shows agreement within the expected uncertainties of both instruments.

The equivalence of three techniques for estimating ground reflectance from LANDSAT digital count data

NASA Technical Reports Server (NTRS)

Richardson, A. J. (Principal Investigator)

1983-01-01

The equivalence of three separate investigations that related LANDSAT digital count (DC) to ground measured reflectance (R) was demonstrated. One investigator related DC data to the cosZ, where Z is the solar zenith angle, for surfaces of constant R. The second investigator corrected the DC data to the solar zenith angle of 39 degrees before relating to surface R. Both of these investigators used LANDSAT 1 and 2 data from overpass dates 1972 through 1977. A third investigator calculated the relation between DC and R based on atmospheric radiative transfer theory. The equation coefficients obtained from these three investigators for all four LANDSAT MSS bands were shown to be equivalent although differences in ground reflectance measurement procedures have created coefficient variations among the three investigations. These relations should be useful for testing atmospheric radiative transfer theory.

Self-consolidating concretes containing waste PET bottles as sand replacement

NASA Astrophysics Data System (ADS)

Khalid, Faisal Sheikh; Azmi, Nurul Bazilah; Mazenan, Puteri Natasya; Shahidan, Shahiron; Othman, Nor hazurina; Guntor, Nickholas Anting Anak

2018-02-01

This study evaluates the effect of self-consolidating concrete (SCC) containing waste polyethylene terephthalate (PET) granules on the fresh, mechanical and water absorption properties. Fine aggregates were replaced from 0% to 8% by PET granules. The fresh properties of SCC containing PET granules were determined using slump flow and V-funnel flow time tests. The compressive and splitting tensile strength were evaluated. The results indicated that utilization of waste PET granules in production of SCC could be an effective way for recycling purpose. The maximum amount of PET replacement should be limited to 5%. Exceeding 5% of PET content may result in an increase of V-funnel flow time to overpass the limiting value, decrease in strength. The production of high performance SCC containing 5% PET granules satisfies all the requirements for SCC with satisfactory outputs.

Secondary Aerosol Formation over the ESCOMPTE Area: Results from airborne Aerosol and Trace Gas Measurements

NASA Astrophysics Data System (ADS)

van Dingenen, R.; Martins-Dos Santos, S.; Putaud, J. P.; Allet, C.; Bretton, E.; Perros, P.

2003-04-01

From June 10th to July 14th 2001, the ESCOMPTE campaign took place in the Marseille-Berre area in Southern France. The goal of the campaign was to produce a high quality 3-D data base from emissions, transport and air composition measurements during urban photochemical pollution episodes at the meso-scale. The CAATER AEROPLUM project was embedded within this international field campaign. AEROPLUM aimed at mapping size distributions of aerosols and photo-oxidants in the mixed layer over the ESCOMPTE domain, using the ARAT Fokker 27 as measurement platform. Aircraft sub-micrometer aerosol measurements are validated during overpasses against ground-based measurements, carried out with similar instrumentation. We will present and discuss data during periods of seabreeze, transporting coastal industrial and urban pollution land-inwards. This leads to intense photochemical activity, evidenced by elevated O_3 concentrations and aerosol levels.

Low-Altitude Satellite Measurements of Pulsating Auroral Electrons

NASA Technical Reports Server (NTRS)

Samara, M.; Michell, R. G.; Redmon, R. J.

2015-01-01

We present observations from the Defense Meteorological Satellite Program and Reimei satellites, where common-volume high-resolution ground-based auroral imaging data are available. These satellite overpasses of ground-based all-sky imagers reveal the specific features of the electron populations responsible for different types of pulsating aurora modulations. The energies causing the pulsating aurora mostly range from 3 keV to 20 keV but can at times extend up to 30 keV. The secondary, low-energy electrons (<1 keV) are diminished from the precipitating distribution when there are strong temporal variations in auroral intensity. There are often persistent spatial structures present inside regions of pulsating aurora, and in these regions there are secondary electrons in the precipitating populations. The reduction of secondary electrons is consistent with the strongly temporally varying pulsating aurora being associated with field-aligned currents and hence parallel potential drops of up to 1 kV.

Multipath induced errors in meteorological Doppler/interferometer location systems

NASA Technical Reports Server (NTRS)

Wallace, R. G.

1984-01-01

One application of an RF interferometer aboard a low-orbiting spacecraft to determine the location of ground-based transmitters is in tracking high-altitude balloons for meteorological studies. A source of error in this application is reflection of the signal from the sea surface. Through propagating and signal analysis, the magnitude of the reflection-induced error in both Doppler frequency measurements and interferometer phase measurements was estimated. The theory of diffuse scattering from random surfaces was applied to obtain the power spectral density of the reflected signal. The processing of the combined direct and reflected signals was then analyzed to find the statistics of the measurement error. It was found that the error varies greatly during the satellite overpass and attains its maximum value at closest approach. The maximum values of interferometer phase error and Doppler frequency error found for the system configuration considered were comparable to thermal noise-induced error.

Satellite Sounder Data Assimilation for Improving Alaska Region Weather Forecast

NASA Technical Reports Server (NTRS)

Zhu, Jiang; Stevens, E.; Zavodsky, B. T.; Zhang, X.; Heinrichs, T.; Broderson, D.

2014-01-01

Data assimilation has been demonstrated very useful in improving both global and regional numerical weather prediction. Alaska has very coarser surface observation sites. On the other hand, it gets much more satellite overpass than lower 48 states. How to utilize satellite data to improve numerical prediction is one of hot topics among weather forecast community in Alaska. The Geographic Information Network of Alaska (GINA) at University of Alaska is conducting study on satellite data assimilation for WRF model. AIRS/CRIS sounder profile data are used to assimilate the initial condition for the customized regional WRF model (GINA-WRF model). Normalized standard deviation, RMSE, and correlation statistic analysis methods are applied to analyze one case of 48 hours forecasts and one month of 24-hour forecasts in order to evaluate the improvement of regional numerical model from Data assimilation. The final goal of the research is to provide improved real-time short-time forecast for Alaska regions.

Performance of Hydrophobisation Techniques in Case of Reinforced Concrete Structures

NASA Astrophysics Data System (ADS)

Błaszczyński, Tomasz; Osesek, Mateusz; Gwozdowski, Błażej; Ilski, Mirosław

2017-10-01

Concrete is, unchangeably, one of the most frequently applied building materials, also in the case of bridges, overpasses or viaducts. Along with the aging of such structures, the degradation of concrete, which may accelerate the corrosion of reinforcing steel and drastically decrease the load-bearing capacity of the structure, becomes an important issue. The paper analyzes the possibilities of using deep hydrophobisation in repairing reinforced concrete engineering structures. The benefits of properly securing reinforced concrete structures from the damaging effects of UV radiation, the influence of harmful gases, or progression of chlorine induced corrosion have been presented, especially in regards to bridge structures. The need to calculate the costs of carrying out investments along with the expected costs of maintaining such structures, as well as the high share of costs connected with logistics, has also been indicated in the total costs of repair works.

KSC-2014-1988

NASA Image and Video Library

2014-03-20

VANDENBERG AIR FORCE BASE, Calif. – The Delta first-stage booster for NASA's Orbiting Carbon Observatory-2 mission, or OCO-2, negotiates an overpass behind its escort vehicles as it makes its way through the roads on Vandenberg Air Force Base in California on its transfer from the Building 836 hangar to the Horizontal Processing Facility at Space Launch Complex 2. OCO-2 is scheduled to launch aboard a United Launch Alliance Delta II rocket on July 1, 2014. The observatory will collect precise global measurements of carbon dioxide in the Earth's atmosphere and provide scientists with a better idea of the chemical compound's impacts on climate change. Scientists will analyze this data to improve our understanding of the natural processes and human activities that regulate the abundance and distribution of this important atmospheric gas. To learn more about OCO-2, visit http://oco.jpl.nasa.gov. Photo credit: NASA/D. Liberotti, 30th Space Wing, VAFB

Wakes from submerged obstacles in an open channel flow

NASA Astrophysics Data System (ADS)

Smith, Geoffrey B.; Marmorino, George; Dong, Charles; Miller, W. D.; Mied, Richard

2015-11-01

Wakes from several submerged obstacles are examined via airborne remote sensing. The primary focus will be bathymetric features in the tidal Potomac river south of Washington, DC, but others may be included as well. In the Potomac the water depth is nominally 10 m with an obstacle height of 8 m, or 80% of the depth. Infrared imagery of the water surface reveals thermal structure suitable both for interpretation of the coherent structures and for estimating surface currents. A novel image processing technique is used to generate two independent scenes with a known time offset from a single overpass from the infrared imagery, suitable for velocity estimation. Color imagery of the suspended sediment also shows suitable texture. Both the `mountain wave' regime and a traditional turbulent wake are observed, depending on flow conditions. Results are validated with in-situ ADCP transects. A computational model is used to further interpret the results.

Development and testing of a rural credit supervision system at the level of counties and rural properties utilizing remote sensing techniqes

NASA Technical Reports Server (NTRS)

Batista, G. T. (Principal Investigator); Delima, A. M.; Tardin, A. T.; Rudorff, B. F. T.; Mendonca, F. J.; Dosanjosferreirapinto, S.; Chen, S. C.; Duarte, V.

1984-01-01

Remote sensing techniques for supporting the rural credit supervision system were developed and tested. The test area comprised the counties of Aracatuba and Guararapes, located in the State of Sao Paulo. Aerial photography, LANDSAT images and topographic charts were used. Aerial photographs were extremely useful for the out lining of properties boundaries with financing of sugarcane plantations by the Banco do Brasil S.A.. The percentage of correctly interpreted sugarcane on LANDSAT images, considering the 85 analyzed properties, was of 63.12%. The occurrence of atypical conditions such as excessive raining, sugarcane in bloom, and wind damaged sugarcane and sugarcane not harvested due to planning failures verified during the period the images were obtained, were some of the contributing factors associated with a low interpretation performance. An alternative approach was developed using several LANDSAT overpasses and auxiliary field data, which resulted in 91.77 percent correct.

Water color and circulation southern Chesapeake Bay, part 1

NASA Technical Reports Server (NTRS)

Nichols, M. M.; Gordon, H. H.

1975-01-01

Satellite imagery from two EREP passes over the Rappahannock Estuary of the Chesapeake region is analyzed to chart colored water types, to delineate color boundaries and define circulatory patterns. Surface observations from boats and helicopters concurrent with Skylab overpass define the distributions of suspended sediment, transparency, temperature, salinity, phytoplankton, color of suspended material and optical ratio. Important features recorded by the imagery are a large-scale turbidity maximum and massive red tide blooms. Water movement is revealed by small-scale mixing patterns and tidal plumes of apparent sediment-laden water. The color patterns broadly reflect the bottom topography and the seaward gradient of suspended material between the river and the bay. Analyses of red, green and natural color photos by microdensitometry demonstrate the utility of charting water color types of potential use for managing estuarine water quality. The Skylab imagery is superior to aerial photography and surface observations for charting water color.

Radiometric gains of satellite sensors of reflected solar radiation - Results from NASA ER-2 aircraft measurements

NASA Technical Reports Server (NTRS)

Abel, Peter; Galimore, Reginald; Cooper, John

1992-01-01

A method for using congruent aircraft-satellite observations to calibrate a satellite sensor is presented. A calibrated spectroradiometer at an altitude of 19 km above White Sands, NM, is oriented to view White Sands at the satellite overpass time along the same view vector as the satellite sensor. Collected data are transformed into corresponding estimates of sensor band radiance at the satellite (derived from the aircraft measurements), and average count (from the sensor measurements). These are both averaged across the footprint of the spectroradiometer. Results are presented for the evolution of NOAA-11 Advanced Very High Resolution Radiometer (AVHRR) (Bands 1 and 2) gain between November 1988 and October 1990, and for GOES-6 and GOES-7 VISSR/VAS visible bands during the same period. Estimates of uncertainty in the results are presented, as well as ideas for their reduction in future flights.

Comparison of C5 and C6 Aqua-MODIS Dark Target Aerosol Validation

NASA Technical Reports Server (NTRS)

Munchak, Leigh A.; Levy, Robert C.; Mattoo, Shana

2014-01-01

We compare C5 and C6 validation to compare the C6 10 km aerosol product against the well validated and trusted aerosol product on global and regional scales. Only the 10 km aerosol product is evaluated in this study, validation of the new C6 3 km aerosol product still needs to be performed. Not all of the time series has processed yet for C5 or C6, and the years processed for the 2 products is not exactly the same (this work is preliminary!). To reduce the impact of outlier observations, MODIS is spatially averaged within 27.5 km of the AERONET site, and AERONET is temporatally averaged within 30 minutes of the MODIS overpass time. Only high quality (QA = 3 over land, QA greater than 0 over ocean) pixels are included in the mean.

Sentinel-3A Views Ocean Variability More Accurately at Finer Resolution

NASA Astrophysics Data System (ADS)

Heslop, E. E.; Sánchez-Román, A.; Pascual, A.; Rodríguez, D.; Reeve, K. A.; Faugère, Y.; Raynal, M.

2017-12-01

This is the first multiplatform evaluation involving data from the new Sentinel-3A altimeter. An experiment was undertaken in the Algerian Basin, employing an ocean glider and a ship mission, along the same track and synchronous with an overpass of the Sentinel-3A mission. This provided three independent views of the ocean velocity field, along a section that encompassed three different oceanographic regimes. The results demonstrate the capacity of Sentinel-3A to retrieve fine-scale oceanographic features ( 20 km). The intercomparison with in situ platforms showed a significant improvement, order 30% in resolution and 42% in velocity accuracy using a synthetic aperture radar mode with respect to lower-resolution mode of conventional altimetry. In addition, the three-platform view provided valuable insight into the variability of evolving oceanographic features, in an area of the Mediterranean that remains chronically under sampled.

Convective climatology over the southwest U.S. and Mexico from passive microwave and infrared data

NASA Technical Reports Server (NTRS)

Negri, Andrew J.; Howard, Kenneth W.; Keehn, Peter R.; Maddox, Robert A.; Adler, Robert F.

1992-01-01

Passive microwave data from the Special Sensor Microwave Imager (SSM/I) were used to estimate the amount of rainfall in the June-August season for the regions of the southwest U.S. and Mexico, and the results are compared to rain-gauge observations and to IR climatologies of Maddox et al. (1992), using both the hourly IR data and IR data sampled at the time of the overpass of the SSM/I. A comparison of the microwave climatology with monthly rainfall measured by the climatological gage network over several states of western Mexico resulted in a 0.63 correlation and a large (482 mm) bias, due to sampling and the incongruity of rain gages and satellite estimates. A comparison between the IR and microwave data showed that the IR tended toward higher percentages along the coast compared to the microwave.

Microvascular Guidance: A Challenge to Support the Development of Vascularised Tissue Engineering Construct

PubMed Central

Sukmana, Irza

2012-01-01

The guidance of endothelial cell organization into a capillary network has been a long-standing challenge in tissue engineering. Some research efforts have been made to develop methods to promote capillary networks inside engineered tissue constructs. Capillary and vascular networks that would mimic blood microvessel function can be used to subsequently facilitate oxygen and nutrient transfer as well as waste removal. Vascularization of engineering tissue construct is one of the most favorable strategies to overpass nutrient and oxygen supply limitation, which is often the major hurdle in developing thick and complex tissue and artificial organ. This paper addresses recent advances and future challenges in developing three-dimensional culture systems to promote tissue construct vascularization allowing mimicking blood microvessel development and function encountered in vivo. Bioreactors systems that have been used to create fully vascularized functional tissue constructs will also be outlined. PMID:22623881

Bigfoot Field Manual, Version 2.1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, J.L.; Burrows, S.; Gower, S.T.

1999-09-01

The BigFoot Project is funded by the Earth Science Enterprise to collect and organize data to be used in the National Aeronautics and Space Administration's Earth Observing System (EOS) Validation Program. The data collected by the BigFoot Project are unique in being ground-based observations coincident with satellite overpasses. In addition to collecting data, the BigFoot project will develop and test new algorithms for scaling point measurements to the same spatial scales as the EOS satellite products. This BigFoot Field Manual will be used to achieve completeness and consistency of data collected at four initial BigFoot sites and at future sitesmore » that may collect similar validation data. Therefore, validation datasets submitted to the Oak Ridge National Laboratory Distributed Active Archive Center that have been compiled in a manner consistent with the field manual will be especially valuable in the validation program.« less

Spectroradiometric calibration of the Thematic Mapper and Multispectral Scanner system

NASA Technical Reports Server (NTRS)

Slater, P. N.; Palmer, J. M. (Principal Investigator)

1984-01-01

Radiometric measurements were taken on the morning of the LANDSAT 5 Thematic Mapper overpass. The sky was cloud free and the sites were dry. Barnes multiband radiometer data were collected for a 4 x 4 pixel area and two fractional pixel areas of slightly higher and lower reflectances than the larger area. Helicopter color photography was obtained of all the ground areas. This photography will allow a detailed reflectance map of the 4 x 4 pixel are to be made and registered to the TM imagery to an accuracy of better than half a pixel. Spectropolarimeter data were also collected of the 4 x 4 pixel area from the helicopter. In addition, ground based solar radiometer data were collected to provide spectral extinction optical thickness valves. The radiative transfer theory used in the development of the Herman code which was used in predicting the TM entrance pupil spectral radiances from the ground based measurements is described.

Use of GLOBE Observations to Derive a Landsat 8 Split Window Algorithm for Urban Heat Island

NASA Astrophysics Data System (ADS)

Fagerstrom, L.; Czajkowski, K. P.

2017-12-01

Surface temperature has been studied to investigate the warming of urban climates, also known as urban heat islands, which can impact urban planning, public health, pollution levels, and energy consumption. However, the full potential of remotely sensed images is limited when analyzing land surface temperature due to the daunting task of correcting for atmospheric effects. Landsat 8 has two thermal infrared sensors. With two bands in the infrared region, a split window algorithm (SWA), can be applied to correct for atmospheric effects. This project used in situ surface temperature measurements from NASA's ground observation program, the Global Learning and Observations to Benefit the Environment (GLOBE), to derive the correcting coefficients for use in the SWA. The GLOBE database provided land surface temperature data that coincided with Landsat 8 overpasses. The land surface temperature derived from Landsat 8 SWA can be used to analyze for urban heat island effect.

Laser line scanning for fluorescence reflectance imaging: a phantom study and in vivo validation of the enhancement of contrast and resolution.

PubMed

Fantoni, Frédéric; Hervé, Lionel; Poher, Vincent; Gioux, Sylvain; Mars, Jérôme I; Dinten, Jean-Marc

2014-01-01

Intraoperative fluorescence imaging in reflectance geometry is an attractive imaging modality to noninvasively monitor fluorescence-targeted tumors. In some situations, this kind of imaging suffers from poor resolution due to the diffusive nature of photons in tissue. The objective of the proposed technique is to tackle this limitation. It relies on the scanning of the medium with a laser line illumination and the acquisition of images at each position of excitation. The detection scheme proposed takes advantage of the stack of images acquired to enhance the resolution and the contrast of the final image. The experimental protocol is described to fully understand why we overpass the classical limits and validate the scheme on tissue-like phantoms and in vivo with a preliminary testing. The results are compared with those obtained with a classical wide-field illumination.

Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions. [Lower Rio Grande Valley Test Site: Weslaco, Texas; Falco Reservoir and the Gulf of Mexico

NASA Technical Reports Server (NTRS)

Wiegand, C. L.; Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J. (Principal Investigator)

1980-01-01

The author has identified the following significant results. HCMM day/night coverage 12 hours apart cannot be obtained at 26 deg N latitude; nor have any pairs 36 hours apart been obtained. A day-IR scene and a night scene for two different dates were analyzed. A profile across the test site for the same latitude shows that the two profiles are near mirror images of each other over land surfaces and that the temperature of two large water bodies, Falcon Reservoir and the Gulf of Mexico, are nearly identical on two dates. During the time interval between overpasses, the vegetative cover remained static due to winter dormancy. The data suggest that day/night temperature differences measured weeks apart may yield meaningful information about the contrast between daytime maximum and nighttime minimum temperatures for a given site.

Trapping fresh sea breeze in desert? Health status of Camanchaca, Atacama's fog.

PubMed

Bonnail, Estefanía; Cunha Lima, Ricardo; Martínez Turrieta, Gladys

2018-05-24

Water fog composition was investigated at a fog harvesting installation in the coast of Atacama (North Chile). Chañaral is historically affected by mining contamination discharges. Hydro-chemical characterization of fog water from top of the mountain (where capture installation is located) and at the bottom of the mountain (after vertical transportation where an aquaponic system is located) revealed many compositional differences that compromise the use of water. High acidity and high concentrations in Cu and As in water collected on top of the mountain were found; meanwhile, acidity and Cu decreased, and As levels overpassed the drinking water standards after the vertical transportation. Collected data was assessed according to national and international regulatory standards, neutralization factors (NF), sodium adsorption ratio (SAR), and ion ratios to determine origin of contamination and suitability of destined for human consumption, irrigation, or aquaculture purposes.

NASA/Cousteau ocean bathymetry experiment. Remote bathymetry using high gain LANDSAT data

NASA Technical Reports Server (NTRS)

Polcyn, F. C.

1976-01-01

Satellite remote bathymetry was varified to 22 m depths where water clarity was defined by alpha = .058 1/m and bottom reflection, r(b), was 26%. High gain band 4 and band 5 CCT data from LANDSAT 1 was used for a test site in the Bahama Islands and near Florida. Near Florida where alpha = .11 1/m and r(b) = 20%, depths to 10 m were verified. Depth accuracies within 10% rms were achieved. Position accuracies within one LANDSAT pixel were obtained by reference to the Transit navigation satellites. The Calypso and the Beayondan, two ships, were at anchor on each of the seven days during LANDSAT 1 and 2 overpasses: LORAN C position information was used when the ships were underway making depth transects. Results are expected to be useful for updating charts showing shoals hazardous to navigation or in monitoring changes in nearshore topography.

Using electric current to surpass the microstructure breakup limit

PubMed Central

Qin, Rongshan

2017-01-01

The elongated droplets and grains can break up into smaller ones. This process is driven by the interfacial free energy minimization, which gives rise to a breakup limit. We demonstrated in this work that the breakup limit can be overpassed drastically by using electric current to interfere. Electric current free energy is dependent on the microstructure configuration. The breakup causes the electric current free energy to reduce in some cases. This compensates the increment of interfacial free energy during breaking up and enables the processing to achieve finer microstructure. With engineering practical electric current parameters, our calculation revealed a significant increment of the obtainable number of particles, showing electric current a powerful microstructure refinement technology. The calculation is validated by our experiments on the breakup of Fe3C-plates in Fe matrix. Furthermore, there is a parameter range that electric current can drive spherical particles to split into smaller ones. PMID:28120919

Comparison of Water Vapor Measurements by Airborne Sun Photometer and Near-Coincident in Situ and Satellite Sensors during INTEX/ITCT 2004

NASA Technical Reports Server (NTRS)

Livingston, J.; Schmid, B.; Redemann, J.; Russell, P. B.; Ramirez, S. A.; Eilers, J.; Gore, W.; Howard, S.; Pommier, J.; Fetzer, E. J.;

Retrieval of aerosol optical and micro-physical properties with 2D-MAX-DOAS

NASA Astrophysics Data System (ADS)

Ortega, Ivan; Coburn, Sean; Hostetler, Chris; Ferrare, Rich; Hair, Johnathan; Kassianov, Evgueni; Barnard, James; Berg, Larry; Schmid, Beat; Tomlinson, Jason; Hodges, Gary; Lantz, Kathy; Wagner, Thomas; Volkamer, Rainer

2015-04-01

Recent retrievals of 2 dimensional (2D) Multi-AXis Differential Optical Absorption Spectroscopy (2D-MAX-DOAS) have highlighted its importance in order to infer diurnal horizontal in-homogeneities around the measurement site. In this work, we expand the capabilities of 2D measurements in order to estimate simultaneously aerosol optical and micro-physical properties. Specifically, we present a retrieval method to obtain: (1) aerosol optical thickness (AOT) in the boundary layer (BL) and free troposphere (FT) and (2) the effective complex refractive index and the effective radius of the aerosol column size distribution. The retrieval method to obtain AOT is based on an iterative comparison of measured normalized radiances, oxygen collision pair (O4), and absolute Raman Scattering Probability (RSP) with the forward model calculations derived with the radiative transfer model McArtim based on defined aerosol extinction profiles. Once the aerosol load is determined we use multiple scattering phase functions and single scattering albedo (SSA) obtained with Mie calculations which then constrain the RTM to forward model solar almucantar normalized radiances. The simulated almucantar normalized radiances are then compared to the measured normalized radiances. The best-fit, determined by minimizing the root mean square, retrieves the complex refractive index, and effective radius. We apply the retrieval approach described above to measurements carried out during the 2012 intensive operation period of the Two Column Aerosol Project (TCAP) held on Cape Cod, MA, USA. Results are presented for two ideal case studies with both large and small aerosol loading and similar air mass outflow from the northeast coast of the US over the West Atlantic Ocean. The aerosol optical properties are compared with several independent instruments, including the NASA Langley airborne High Spectral Resolution Lidar (HSRL-2) for highly resolved extinction profiles during the overpasses, and with the co-located Multi Filter Rotating Shadow band Radiometer (MFRSR), and the Cimel Sun photometer for aerosol load at several wavelengths. To test aerosol horizontal homogeneity we use quantitatively analysis of asymmetry of solar azimuth normalized radiances and RSP. The aerosol column microphysical properties will be compared with merged size distribution of several in-situ instruments from airborne measurements during overpasses of the DoE-G1 aircraft around the ground measurement site.

Towards global Landsat burned area mapping: revisit time and availability of cloud free observations

NASA Astrophysics Data System (ADS)

Melchiorre, A.; Boschetti, L.

2016-12-01

Global, daily coarse resolution satellite data have been extensively used for systematic burned area mapping (Giglio et al. 2013; Mouillot et al. 2014). The adoption of similar approaches for producing moderate resolution (10 - 30 m) global burned area products would lead to very significant improvements for the wide variety of fire information users. It would meet a demand for accurate burned area perimeters needed for fire management, post-fire assessment and environmental restoration, and would lead to more accurate and precise atmospheric emission estimations, especially over heterogeneous areas (Mouillot et al. 2014; Randerson et al. 2012; van der Werf et al. 2010). The increased spatial resolution clearly benefits mapping accuracy: the reduction of mixed pixels directly translates in increased spectral separation compared to coarse resolution data. As a tradeoff, the lower temporal resolution (e.g. 16 days for Landsat), could potentially cause large omission errors in ecosystems with fast post-fire recovery. The spectral signal due to the fire effects is non-permanent, can be detected for a period ranging from a few weeks in savannas and grasslands, to over a year in forest ecosystems (Roy et al. 2010). Additionally, clouds, smoke, and other optically thick aerosols limit the number of available observations (Roy et al. 2008; Smith and Wooster 2005), exacerbating the issues related to mapping burned areas globally with moderate resolution sensors. This study presents a global analysis of the effect of cloud cover on Landsat data availability over burned areas, by analyzing the MODIS data record of burned area (MCD45) and cloud detections (MOD35), and combining it with the Landsat acquisition calendar and viewing geometry. For each pixel classified as burned in the MCD45 product, the MOD35 data are used to determine how many cloud free observations would have been available on Landsat overpass days, within the period of observability of the burned area spectral signal in the specific ecosystem. If a burned area pixel is covered by clouds on all the post-fire Landsat overpass days, we assume that it would not be detected in a hypothetical Landsat global burned area product. The resulting maps of expected omission errors are combined for the full 15-year MODIS dataset, and summarized by ecoregion and landcover class.

Lava discharge rate and effusive pattern at Piton de la Fournaise from MODIS data

NASA Astrophysics Data System (ADS)

Coppola, D.; Piscopo, D.; Staudacher, T.; Cigolini, C.

2009-07-01

We analysed the effusive activity of 15 eruptions of Piton de la Fournaise by using the data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) during 2003-2007 period. Thermal anomalies were detected by adjusting the values of the Normalised Thermal Index (NTI) threshold [Wright, R.L., Flynn, H., Garbeil, A.J.L., Harris Pilger, E., 2002. Automated volcanic eruption detection using MODIS. Remote Sens. Environ. 82: 135-155.] in accord to the seasonal and topographic variations of the background temperature at Piton de la Fournaise. Each satellite overpass, has been classified according to the presence of clouds and the satellite viewing geometry. The analyzed data indicate that at Piton de la Fournaise only 10% of MODIS overpasses occurred in optimal conditions (clear sky and satellite zenith < 40°). However this classification allowed us to use the 4 μm radiance to estimate time average of lava discharge rates (TADR) for most of the analysed eruptions. These data has been used to compare the inferred effusive pattern with the real time seismic amplitude data (RSAM) recorded during the same events. We found that summit eruptions, characterised by a lower discharge rate (< 2 m 3s - 1 ), induce a separation of the gas phase which translate into a decoupling between TADR and RSAM. This regime coupled with the low magma ascent rate and the typical steady effusion of these eruptions imply a very low pressurization of the shallower reservoir which is consistent with a direct overflow of the magma supplied from depth. Conversely, the distal eruptions show a TADR linearly correlated with the RSAM thus indicating a more homogeneous degassing regime and the absence of gas accumulation process within the shallow reservoir. The high initial TADR (> 20 m 3 s - 1 ) and the following vanishing phase indicate that distal eruptions are triggered when a critical overpressure is reached (>5 MPa). This last seems to be increased during the whole analysed period up to the onset of the April 2007 which led to the collaps of the Dolomieu crater. Finally we propose that the recent activity of PdF may result from a persistent loading of the shallow reservoir with a magma supply rate which increased from 1135 kg s - 1 to 4310 kg s - 1 during the period between 2003 and 2007.

Satellite-Derived NO2 as an Indicator of Urban Air Quality and Emissions

NASA Astrophysics Data System (ADS)

Holloway, T.; Penn, E.; Harkey, M.

2016-12-01

Nitrogen dioxide (NO2) is the satellite-derived constituent with the most direct connection to fossil fuel emissions. At present the Ozone Monitoring Instrument aboard the NASA Aura satellite offers the highest resolution NO2retrievals, and new missions under development (TropOMI, TEMPO, GEMS, Sentinel-4) offer the potential for improved data in coming years. We present results applying satellite-derived NO2data to characterize air quality and emissions in U.S. cities. We highlight research findings geared toward increasing the relevance of satellite data to evaluate urban-scale air quality issues. This work reflects activities under the NASA Air Quality Applied Sciences Team (AQAST), and emerging work under the NASA Health and Air Quality Applied Sciences Team (H-AQAST). Among our results is a characterization of the diurnal cycle of nitrogen oxides using ground-based observations and satellite data. In situ monitoring from the U.S. EPA Air Quality System (AQS) shows that most locations have two daily peaks in NO2 (morning and evening) and a single daily peak in NO (morning). Spaced-based observations from the ESA Global Ozone Monitoring Experiment-2 (GOME-2), with a mid-morning overpass, and the NASA OMI, with an early afternoon overpass, support a complementary analysis for characterizing diurnal variability in NO2. Both ground-based monitors and satellite data show a reduction in the amplitude of the diurnal NO2 cycle. In the Western U.S., satellite data showed evidence of higher NO2 in urban centers in the afternoon (OMI) and higher NO2 in suburban areas in the morning (GOME-2), consistent with diurnal traffic patterns associated with commuting. Some power plants in the Western U.S. showed an increase in NO2in the afternoon, consistent with peak power demand associated with building air conditioning use. We extend this city-focused analysis satellite-derived HCHO:NO2 ratios as an indicator of ozone production regime, comparing modeled and measured ratios across major U.S. cities. Past studies have used the ratio of OMI HCHO to OMI NO2 to characterize whether ozone production in a particular location is NOx-limited or VOC-limited. We consider how this satellite-based ratio informs urban ozone chemistry across major U.S. cities.

Global Near Real-Time MODIS and Landsat Flood Mapping and Product Delivery

NASA Astrophysics Data System (ADS)

Policelli, F. S.; Slayback, D. A.; Tokay, M. M.; Brakenridge, G. R.

2014-12-01

Flooding is the most destructive, frequent, and costly natural disaster faced by modern society, and is increasing in frequency and damage (deaths, displacements, and financial costs) as populations increase and climate change generates more extreme weather events. When major flooding events occur, the disaster management community needs frequently updated and easily accessible information to better understand the extent of flooding and coordinate response efforts. With funding from NASA's Applied Sciences program, we developed and are now operating a near real-time global flood mapping system to help provide flood extent information within 24-48 hours of events. The principal element of the system applies a water detection algorithm to MODIS imagery, which is processed by the LANCE (Land Atmosphere Near real-time Capability for EOS) system at NASA Goddard within a few hours of satellite overpass. Using imagery from both the Terra (10:30 AM local time overpass) and Aqua (1:30 PM) platforms allows the system to deliver an initial daily assessment of flood extent by late afternoon, and more robust assessments after accumulating cloud-free imagery over several days. Cloud cover is the primary limitation in detecting surface water from MODIS imagery. Other issues include the relatively coarse scale of the MODIS imagery (250 meters) for some events, the difficulty of detecting flood waters in areas with continuous canopy cover, confusion of shadow (cloud or terrain) with water, and accurately identifying detected water as flood as opposed to normal water extent. We are working on improvements to address these limitations. We have also begun delivery of near real time water maps at 30 m resolution from Landsat imagery. Although Landsat is not available daily globally, but only every 8 days if imagery from both operating platforms (Landsat 7 and 8) is accessed, it can provide useful higher resolution data on water extent when a clear acquisition coincides with an active flood event. These data products are provided in various formats on our website, and also via live OGC (Open Geospatial Consortium) services, and ArcGIS Online accessible web maps, allowing easy access from a variety of platforms, from desktop GIS software to web browsers on mobile phones. https://oas.gsfc.nasa.gov/floodmap

Detecting volcanic sulfur dioxide plumes in the Northern Hemisphere using the Brewer spectrophotometers, other networks, and satellite observations

NASA Astrophysics Data System (ADS)

Zerefos, Christos S.; Eleftheratos, Kostas; Kapsomenakis, John; Solomos, Stavros; Inness, Antje; Balis, Dimitris; Redondas, Alberto; Eskes, Henk; Allaart, Marc; Amiridis, Vassilis; Dahlback, Arne; De Bock, Veerle; Diémoz, Henri; Engelmann, Ronny; Eriksen, Paul; Fioletov, Vitali; Gröbner, Julian; Heikkilä, Anu; Petropavlovskikh, Irina; Jarosławski, Janusz; Josefsson, Weine; Karppinen, Tomi; Köhler, Ulf; Meleti, Charoula; Repapis, Christos; Rimmer, John; Savinykh, Vladimir; Shirotov, Vadim; Siani, Anna Maria; Smedley, Andrew R. D.; Stanek, Martin; Stübi, René

2017-01-01

This study examines the adequacy of the existing Brewer network to supplement other networks from the ground and space to detect SO2 plumes of volcanic origin. It was found that large volcanic eruptions of the last decade in the Northern Hemisphere have a positive columnar SO2 signal seen by the Brewer instruments located under the plume. It is shown that a few days after the eruption the Brewer instrument is capable of detecting significant columnar SO2 increases, exceeding on average 2 DU relative to an unperturbed pre-volcanic 10-day baseline, with a mean close to 0 and σ = 0.46, as calculated from the 32 Brewer stations under study. Intercomparisons with independent measurements from the ground and space as well as theoretical calculations corroborate the capability of the Brewer network to detect volcanic plumes. For instance, the comparison with OMI (Ozone Monitoring Instrument) and GOME-2 (Global Ozone Monitoring Experiment-2) SO2 space-borne retrievals shows statistically significant agreement between the Brewer network data and the collocated satellite overpasses in the case of the Kasatochi eruption. Unfortunately, due to sparsity of satellite data, the significant positive departures seen in the Brewer and other ground networks following the Eyjafjallajökull, Bárðarbunga and Nabro eruptions could not be statistically confirmed by the data from satellite overpasses. A model exercise from the MACC (Monitoring Atmospheric Composition and Climate) project shows that the large increases in SO2 over Europe following the Bárðarbunga eruption in Iceland were not caused by local pollution sources or ship emissions but were clearly linked to the volcanic eruption. Sulfur dioxide positive departures in Europe following Bárðarbunga could be traced by other networks from the free troposphere down to the surface (AirBase (European air quality database) and EARLINET (European Aerosol Research Lidar Network)). We propose that by combining Brewer data with that from other networks and satellites, a useful tool aided by trajectory analyses and modelling could be created which can also be used to forecast high SO2 values both at ground level and in air flight corridors following future eruptions.

Upper ocean fine-scale features in synthetic aperture radar imagery. Part I: Simultaneous satellite and in-situ measurements

NASA Astrophysics Data System (ADS)

Soloviev, A.; Maingot, C.; Matt, S.; Fenton, J.; Lehner, S.; Brusch, S.; Perrie, W. A.; Zhang, B.

2011-12-01

The new generation of synthetic aperture radar (SAR) satellites provides high resolution images that open new opportunities for identifying and studying fine features in the upper ocean. The problem is, however, that SAR images of the sea surface can be affected by atmospheric phenomena (rain cells, fronts, internal waves, etc.). Implementation of in-situ techniques in conjunction with SAR is instrumental for discerning the origin of features on the image. This work is aimed at the interpretation of natural and artificial features in SAR images. These features can include fresh water lenses, sharp frontal interfaces, internal wave signatures, as well as slicks of artificial and natural origin. We have conducted field experiments in the summer of 2008 and 2010 and in the spring of 2011 to collect in-situ measurements coordinated with overpasses of the TerraSAR-X, RADARSAT-2, ALOS PALSAR, and COSMO SkyMed satellites. The in-situ sensors deployed in the Straits of Florida included a vessel-mounted sonar and CTD system to record near-surface data on stratification and frontal boundaries, a bottom-mounted Nortek AWAC system to gather information on currents and directional wave spectra, an ADCP mooring at a 240 m isobath, and a meteorological station. A nearby NOAA NEXRAD Doppler radar station provided a record of rainfall in the area. Controlled releases of menhaden fish oil were performed from our vessel before several satellite overpasses in order to evaluate the effect of surface active materials on visibility of sea surface features in SAR imagery under different wind-wave conditions. We found evidence in the satellite images of rain cells, squall lines, internal waves of atmospheric and possibly oceanic origin, oceanic frontal interfaces and submesoscale eddies, as well as anthropogenic signatures of ships and their wakes, and near-shore surface slicks. The combination of satellite imagery and coordinated in-situ measurements was helpful in interpreting fine-scale features on the sea surface observed in the SAR images and, in some cases, linking them to thermohaline features in the upper ocean. Finally, we have been able to reproduce SAR signatures of freshwater plumes and sharp frontal interfaces interacting with wind stress, as well as internal waves by combining hydrodynamic simulations with a radar imaging algorithm. The modeling results are presented in a companion paper (Matt et al., 2011).

Balloon Borne Soundings of Water Vapor, Ozone and Temperature in the Upper Tropospheric and Lower Stratosphere as Part of the Second SAGE III Ozone Loss and Validation Experiment (SOLVE-2)

NASA Technical Reports Server (NTRS)

Voemel, Holger

2004-01-01

The main goal of our work was to provide in situ water vapor and ozone profiles in the upper troposphere and lower stratosphere as reference measurements for the validation of SAGE III water vapor and ozone retrievals. We used the NOAA/CMDL frost point hygrometer and ECC ozone sondes on small research balloons to provide continuous profiles between the surface and the mid stratosphere. The NOAA/CMDL frost point hygrometer is currently the only lightweight balloon borne instrument capable of measuring water vapor between the lower troposphere and middle stratosphere. The validation measurements were based in the arctic region of Scandinavia for northern hemisphere observations and in New Zealand for southern hemisphere observations and timed to coincide with overpasses of the SAGE III instrument. In addition to SAGE III validation we also tried to coordinate launches with other instruments and studied dehydration and transport processes in the Arctic stratospheric vortex.

Cross calibration of the Landsat-7 ETM+ and EO-1 ALI sensor

USGS Publications Warehouse

Chander, G.; Meyer, D.J.; Helder, D.L.

2004-01-01

As part of the Earth Observer 1 (EO-1) Mission, the Advanced Land Imager (ALI) demonstrates a potential technological direction for Landsat Data Continuity Missions. To evaluate ALI's capabilities in this role, a cross-calibration methodology has been developed using image pairs from the Landsat-7 (L7) Enhanced Thematic Mapper Plus (ETM+) and EO-1 (ALI) to verify the radiometric calibration of ALI with respect to the well-calibrated L7 ETM+ sensor. Results have been obtained using two different approaches. The first approach involves calibration of nearly simultaneous surface observations based on image statistics from areas observed simultaneously by the two sensors. The second approach uses vicarious calibration techniques to compare the predicted top-of-atmosphere radiance derived from ground reference data collected during the overpass to the measured radiance obtained from the sensor. The results indicate that the relative sensor chip assemblies gains agree with the ETM+ visible and near-infrared bands to within 2% and the shortwave infrared bands to within 4%.

Whichever way the wind blows, scientists and engineers try to find ways to protect people and property

NASA Astrophysics Data System (ADS)

Showstack, Randy

Timothy Marshall, a failure and damage consultant with the Haag Engineering Company in Dallas, Texas, possesses a passion for storm chasing. On the afternoon of May 3, 1999, with atmospheric conditions creating a potentially explosive situation, Marshall drove several hours north to central Oklahoma to spot tornadoes. A storm started blowing up near Lawton and moved parallel to Interstate 44, with Marshall ahead of it in his Chevy pickup. He parked on the Newcastle overpass bridge, videotaping the long-tracked twister for later study At 7:04 p.m. local time, with the vortex now just one mile away and moving straight toward him, it started appearing three-dimensional, debris and projectiles flying about, the tornado roaring like freight trains, wind howling, red mud raining down, and things “getting a little out of hand,” Marshall recalled. He drove out of its path, only to watch the tornado tear through the suburban streets and houses of Moore, on its way to Oklahoma City.

The ground-truth problem for satellite estimates of rain rate

NASA Technical Reports Server (NTRS)

North, Gerald R.; Valdes, Juan B.; Eunho, HA; Shen, Samuel S. P.

1994-01-01

In this paper a scheme is proposed to use a point raingage to compare contemporaneous measurements of rain rate from a single-field-of-view (FOV) estimate based on a satellite remote sensor such as a microwave radiometer. Even in the ideal case the measurements are different because one is at a point and the other is an area average over the field of view. Also the point gage will be located randomly inside the field of view on different overpasses. A space-time spectral formalism is combined with a simple stochastic rain field to find the mean-square deviations between the two systems. It is found that by combining about 60 visits of the satellite to the ground-truth site, the expected error can be reduced to about 10% of the standard deviation of the fluctuations of the systems alone. This seems to be a useful level of tolerance in terms of isolating and evaluating typical biases that might be contaminating retrieval algorithms.

Weather conditions associated with autumn migration by mule deer in Wyoming.

PubMed

Rittenhouse, Chadwick D; Mong, Tony W; Hart, Thomas

2015-01-01

Maintaining ecological integrity necessitates a proactive approach of identifying and acquiring lands to conserve unfragmented landscapes, as well as evaluating existing mitigation strategies to increase connectivity in fragmented landscapes. The increased use of highway underpasses and overpasses to restore connectivity for wildlife species offers clear conservation benefits, yet also presents a unique opportunity to understand how weather conditions may impact movement of wildlife species. We used remote camera observations (19,480) from an existing wildlife highway underpass in Wyoming and daily meteorological observations to quantify weather conditions associated with autumn migration of mule deer in 2009 and 2010. We identified minimal daily temperature and snow depth as proximate cues associated with mule deer migration to winter range. These weather cues were consistent across does and bucks, but differed slightly by year. Additionally, extreme early season snow depth or cold temperature events appear to be associated with onset of migration. This information will assist wildlife managers and transportation officials as they plan future projects to maintain and enhance migration routes for mule deer.

A Landsat study of water quality in Lake Okeechobee

NASA Technical Reports Server (NTRS)

Gervin, J. C.; Marshall, M. L.

1976-01-01

This paper uses multiple regression techniques to investigate the relationship between Landsat radiance values and water quality measurements. For a period of over one year, the Central and Southern Florida Flood Control District sampled the water of Lake Okeechobee for chlorophyll, carotenoids, turbidity, and various nutrients at the time of Landsat overpasses. Using an overlay map of the sampling stations, Landsat radiance values were measured from computer compatible tapes using a GE image 100 and averaging over a 22-acre area at each station. These radiance values in four bands were used to form a number of functions (powers, logarithms, exponentials, and ratios), which were then compared with the ground measurements using multiple linear regression techniques. Several dates were used to provide generality and to study possible seasonal variations. Individual correlations were presented for the various water quality parameters and best fit equations were examined for chlorophyll and turbidity. The results and their relationship to past hydrological research were discussed.

EAQUATE: An International Experiment for Hyper-Spectral Atmospheric Sounding Validation

NASA Technical Reports Server (NTRS)

Taylor, J. P.; Smith, W.; Cuomo, V.; Larar, A.; Zhou, D.; Serio, C.; Maestri, T.; Rizzi, R.; Newman, S.; Antonelli, P.;

Landsat-7 long-term acquisition plan radiometry - evolution over time

USGS Publications Warehouse

Markham, Brian L; Goward, Samuel; Arvidson, Terry; Barsi, Julia A.; Scaramuzza, Pat

2006-01-01

The Landsat-7 Enhanced Thematic Mapper Plus instrument has two selectable gains for each spectral band. In the acquisition plan, the gains were initially set to maximize the entropy in each scene. One unintended consequence of this strategy was that, at times, dense vegetation saturated band 4 and deserts saturated all bands. A revised strategy, based on a land-cover classification and sun angle thresholds, reduced saturation, but resulted in gain changes occurring within the same scene on multiple overpasses. As the gain changes cause some loss of data and difficulties for some ground processing systems, a procedure was devised to shift the gain changes to the nearest predicted cloudy scenes. The results are still not totally satisfactory as gain changes still impact some scenes and saturation still occurs, particularly in ephemerally snow-covered regions. A primary conclusion of our experience with variable gain on Landsat-7 is that such an approach should not be employed on future global monitoring missions.

Cloud fraction, layer, and direction of movement results from sky cameras during the FIRE IFO, Coffeyville, Kansas, experiment for the period Nov. 12 through Dec. 9, 1991

NASA Technical Reports Server (NTRS)

Purgold, Gerald C.; Wheeler, Robert J.; Whitlock, Charles H.

1992-01-01

Tables and figures are presented which show local site observations of cloud fractions, the number of cloud layers, direction of movement, and precipitation data collected during the FIRE (First ISCCP Regional Experiment) Phase 2 Cirrus Intensive Field Observations (IFO) conducted in Coffeyville, Kansas during November and December, 1991. Selected data are also presented at the times of the TIROS Operational Vertical Sounder (TOVS) satellite overpass. Several major scientific projects have used surface-based observations of clouds to compare directly with those being observed from satellites. Characterizing the physical properties of clouds is extremely useful in obtaining a more accurate analysis of the effect of clouds and their movements on weather and climate. It is the purpose of this paper to report data collected during the FIRE Phase 2 IFO experiment and to provide a brief history of such a surface-based system and the technical information required for recording local cloud parameters.

A day-to-day comparison study of Seasat scatterometer winds with winds observed from islands in the tropical Pacific

NASA Technical Reports Server (NTRS)

Davison, Jerry; Harrison, D. E.

1989-01-01

The winds derived from the Seasat-A Satellite Scatterometer (SASS) measurements have been the subject of great interest since the 1978 mission, because of the promise of radically improved wind observations over the world ocean. Due to the early end of the mission, only a few of the planned ground truth validation experiments could be made, and the subsequent lack of sufficient high quality independent wind data for comparison has limited the ability to resolve critical issues regarding the scatterometer's performance and the correct interpretation of its signal. Operational weather observations were made of ocean winds independent of Seasat mission plans during the Seasat mission period; the results are reported of a comparison study using such observations. Previous verification with in situ winds has been primarily in middle latitudes (GOASEX, JASIN, and NDBO buoys); winds observed from nine tropical Pacific islands are compared with nearly contemporaneous measurements taken by SASS during overpasses of the islands.

The use of ERTS-1 to more fully utilize and apply marine station data to the study and productivity along the eastern shelf waters of the United States

NASA Technical Reports Server (NTRS)

Marshall, H. G. (Principal Investigator); Bowker, D. E.; Witte, W. G.

1976-01-01

The author has identified the following significant results. Sea truth data were obtained during two ERTS overpasses in waters near the entrance of the Chesapeake Bay. Correlations were made between total phytoplankton and chlorophyll values in these waters to radiance detected by ERTS in an effort to map areas of similar productivity levels. Band 4 radiance had the highest correlation to all parameters with bands 5 and 6 showing decreasing correlations in each case. The radiance values were apparently influenced by one or more factors, most likely including the sediment content of the water. Data have shown that ERTS MSS is not suitable for monitoring chlorophyll in near-shore waters where sediment loads are high. It is suggested that in more seaward or pelagic locations, that ERTS MSS would be more efficient in monitoring surface chlorophyll values and establishing direct relationships to phytoplankton concentrations.

Transforming GIS data into functional road models for large-scale traffic simulation.

PubMed

Wilkie, David; Sewall, Jason; Lin, Ming C

2012-06-01

There exists a vast amount of geographic information system (GIS) data that model road networks around the world as polylines with attributes. In this form, the data are insufficient for applications such as simulation and 3D visualization-tools which will grow in power and demand as sensor data become more pervasive and as governments try to optimize their existing physical infrastructure. In this paper, we propose an efficient method for enhancing a road map from a GIS database to create a geometrically and topologically consistent 3D model to be used in real-time traffic simulation, interactive visualization of virtual worlds, and autonomous vehicle navigation. The resulting representation provides important road features for traffic simulations, including ramps, highways, overpasses, legal merge zones, and intersections with arbitrary states, and it is independent of the simulation methodologies. We test the 3D models of road networks generated by our algorithm on real-time traffic simulation using both macroscopic and microscopic techniques.

A Case Study on Sustainable Reuse of Abandoned Infrastructure at Seoul Station Overpass as Urban Park for the Design Strategies in Korea

NASA Astrophysics Data System (ADS)

Boo, Yeeun; Kwon, Young-Sang

2018-04-01

As the 21st century, known for knowledge information era, many industrial infrastructures built as part of the 20th century urban development have been devastated functionally and new alternatives for them have been demanded nowadays. This study aims to discuss the strategies used in the design proposals of the International Competition for ‘Seoullo 7017 Project’, which was recently completed in May 2017, based on the sustainability of the deteriorate infrastructure as urban park. Through the competition brief, each proposal is analysed against the competition brief and the more generic approaches on the adaptive reuse of infrastructure are proposed. By examining the case in Korea, it is expected to explore the possibilities for the sustainability of abandoned infrastructure through adapting reuse as urban park in Korea, to propose design strategies that can be applied to the future adaptive use of deteriorated infrastructure in Korea, and to provide broader academic base to related works.

HCMM energy budget data as a model input for assessing regions of high potential groundwater pollution

NASA Technical Reports Server (NTRS)

Moore, D. G. (Principal Investigator); Heilman, J.; Beutler, G.

1978-01-01

The author has identified the following significant results. In early April 1978, heavy spring runoff from snowmelt caused significant flooding along a portion of the Big Sioux River Basin in southeastern South Dakota. The flooded area was visible from surrounding areas on a May 15 HCMM IR test image. On May 15, the flood waters had receded but an area of anomalous residual high soil moisture remained. The high soil moisture area was not visible on a HCMM day visible test image of the same scene, or on LANDSAT imagery. To evaluate the effect of water table depth on surface temperatures, thermal scanner data collected on September 5 and 6, 1978 at approximate HCMM overpass times at an altitude of 3650 m were analyzed. Apparent surface temperatures measured by the scanner included emittance contributions from soil surface and the land cover. Results indicated that the shallow water tables produced a damping of the amplitude of the diurnal surface temperature wave.

California coast nearshore processes study

NASA Technical Reports Server (NTRS)

Pirie, D. M. (Principal Investigator); Steller, D. D.

1973-01-01

The author has identified the following significant results. Remote sensor aircraft flights took place simultaneously with ERTS-1 overpasses at the San Francisco, Monterey Bay, and Santa Barbara test cells. The cameras and scanners used were configured for detecting suspended sediment and for maximum water penetration. The Ektachrome/Wratten 12 photographs which were intentionally overexposed 1-1/2 stops were found to show the most extensive sediment transport detail. Minus blue/K 2 photographs illustrate nearshore underwater bottom detail including the head of the Mugu submarine canyon. The EMSIDE 9 channel scanner was employed to classify and differentiate suspended sediment, oil, kelp, and other materials found in the nearshore area. Processing of bulk ERTS-1 computer compatible tapes was utilized to enhance and analyze nearshore sediments. This technique was most successful in enhancing subtle nearshore features found to be faint or invisible on prints made from the supplied negatives. In addition to this continuing computer process, an effort was initiated to interface density values from the bulk tapes into contouring and mapping software.

Satellite detection of oil on the marine surface

NASA Technical Reports Server (NTRS)

Wilson, M. J.; Oneill, P. E.; Estes, J. E.

1981-01-01

The ability of two widely dissimilar spaceborne imaging sensors to detect surface oil accumulations in the marine environment has been evaluated using broadly different techniques. Digital Landsat multispectral scanner (MSS) data consisting of two visible and two near infrared channels has been processed to enhance contrast between areas of known oil coverage and background clean surface water. These enhanced images have then been compared to surface verification data gathered by aerial reconnaissance during the October 15, 1975, Landsat overpass. A similar evaluation of oil slick imaging potential has been made for digitally enhanced Seasat-A synthetic aperture radar (SAR) data from July 18, 1979. Due to the premature failure of this satellite, however, no concurrent surface verification data were collected. As a substitute, oil slick configuration information has been generated for the comparison using meteorological and oceanographic data. The test site utilized in both studies was the extensive area of natural seepage located off Coal Oil Point, adjacent to the University of California, Santa Barbara.

MIZEX, 1984, NASA CV-990 flight report

NASA Technical Reports Server (NTRS)

1985-01-01

During June/July 1984, the NASA CV-990 Airborne Laboratory was utilized in a mission to overly the Fram Strait/East Greenland Sea marginal ice zone (MIZ) during the main summer marginal ice zone experiment (MIZEX '84). The eight data flights were coordinated where possible with overpasses of the Nimbus-7 satellite, and with measurement of sea ice, open ocean, and atmospheric properties at the surface. The surface research teams were based on seven research vessels, some with helicopters: (1) M/V Kvitbjorn, (2) M/V Polarqueen; (3) M/S Haakon Mosby; (4) a M/S H.U. Sverdrup, all from Norway; (5) F/S Polarstern from the Federal Republic of Germany; and (6) the USNS Lynch from the USA. There were also coordinated flights with the NRL P3, NOAA P3, Canadian CV580, and the French B-17 during the overlap portions of their respective missions. Analysis of the real-time data acquired during the mission and uncalibrated data stored on tape has served to indicate the mission was over 90% successful.

Status of GeoTASO Trace Gas Data Analysis for the KORUS-AQ Campaign

NASA Astrophysics Data System (ADS)

Janz, S. J.; Nowlan, C. R.; Lamsal, L. N.; Kowalewski, M. G.; Judd, L. M.; Wang, J.

2017-12-01

The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) instrument measures spectrally resolved backscattered solar radiation at high spatial resolution. The instrument completed 30 sorties on board the NASA LaRC UC-12 aircraft during the KORUS-AQ deployment in May-June of 2016. GeoTASO collects spatially resolved spectra with sufficient sensitivity to retrieve column amounts of the trace gas molecules NO2, SO2, H2CO, O3, and C2H2O2 as well as aerosol products. Typical product retrievals are done in 250 m2 bins with multiple overpasses of key ground sites, allowing for detailed spatio-temporal analysis. Flight patterns consisted of both contiguous overlapping grid patterns to simulate satellite observational strategies in support of future geostationary satellite algorithm development, and "race-track" sampling to perform calibration and validation with the in-situ DC-8 platform as well as ground based assets. We will summarize the status of the radiance data set as well as ongoing analysis from our co-Investigators.

Satellite Monitoring of Long Term Changes in Intertidal Thermal Conditions

NASA Astrophysics Data System (ADS)

Purvis, C. L.; Lakshmi, V.; Helmuth, B.

2006-12-01

Documented trends of global climate change have implications for species dynamics, range boundaries and mortality rates. A generalized assumption about global warming is that species will shift poleward in response to the increased temperatures, thereby displacing pre-existing species at higher latitudes. However, studies such as those conducted along the rocky shorelines of the U.S. have shown that such a simplified ecosystem response is unrealistic. Habitat alterations due to climate change are greatly influenced by local conditions, resulting in a patchwork of varying responses to temperature changes all along the intertidal. In order to capture these spatially- and temporally-dependent dynamics, satellite observations of land and sea surface temperatures (LST and SST) have been assimilated for the Pacific coast from Vancouver Island to southern California. Images from three satellite sensors were included in the study: MODIS/Terra, MODIS/Aqua and ASTER/Terra. MODIS has a spatial resolution of 1km (LST) and 4km (SST), daily coverage and overpass times of 10:30am and 1:30pm. ASTER has a spatial resolution of 90m (LST), sporadic temporal coverage due to an on-demand status and a 10:30am crossing time. The remotely sensed data were statistically compared to nearly 10 years of in situ measurements of body temperature of the California mussel along the Pacific coast. This species is prevalent among the rocky intertidal areas, physiologically well studied in terms of heat response and situated in a thermally harsh environment which demonstrates strong responses to climate change. A regression was performed to account for noise such as tidal signals, changes in latitude among sites as well as seasonal fluctuations in body temperature. Comparisons show that while the satellite data are unable to capture many of the daily maximum body temperatures (due to overpass times), they do offer a fairly accurate method of capturing high temporal resolution temperatures over large areas. In addition, satellite measurements were utilized to investigate the spatial distribution of intertidal mussels in Humboldt Bay, CA. In situ measurements are not prevalent enough to explain the potentially heat-driven range of mussels in this critical habitat, and therefore remotely sensed data will be used to gather new insight into thermally-regulated range boundaries of this species. By incorporating satellite measurements into in-depth habitat studies, long term thermal variations due to climate change can be monitored over large regions and aid in capturing larger-scale impacts which cannot be accomplished by tedious, site-specific in situ studies.

Induced accumulation of Au, Ag and Cu in Brassica napus grown in a mine tailings with the inoculation of Aspergillus niger and the application of two chemical compounds.

PubMed

González-Valdez, Eduardo; Alarcón, Alejandro; Ferrera-Cerrato, Ronald; Vega-Carrillo, Héctor René; Maldonado-Vega, María; Salas-Luévano, Miguel Ángel; Argumedo-Delira, Rosalba

2018-06-15

This study evaluated the ability of Brassica napus for extracting gold (Au), silver (Ag) and copper (Cu) from a mine tailings, with the inoculation of two Aspergillus niger strains, and the application of ammonium thiocyanate (NH 4 SCN) or ammonium thiosulfate [(NH 4 ) 2 S 2 O 3 ]. After seven weeks of growth inoculated or non-inoculated plants were applied with 1 or 2 g kg -1 of either NH 4 SCN or (NH 4 ) 2 S 2 O 3 , respectively. Eight days after the application of the chemical compounds, plants were harvested for determining the total dry biomass, and the content of Au, Ag, and Cu in plant organs. Application of (NH 4 ) 2 S 2 O 3 or NH 4 SCN resulted in enhanced Au-accumulation in stems (447% and 507%, respectively), while either (NH 4 ) 2 S 2 O 3 +Aspergillus, or NH 4 SCN increased the Au-accumulation in roots (198.5% and 404%, respectively) when compared to the control. Treatments with (NH 4 ) 2 S 2 O 3 or (NH 4 ) 2 S 2 O 3 +Aspergillus significantly increased (P ≤ 0.001) the accumulation of Ag in leaves (677% and 1376%, respectively), while NH 4 SCN + Aspergillus, and (NH 4 ) 2 S 2 O 3 enhanced the accumulation in stems (7153% and 6717.5%). The Ag-accumulation in roots was stimulated by NH 4 SCN+ Aspergillus, and (NH 4 ) 2 S 2 O 3 + Aspergillus (132.5% and 178%, respectively), when compared to the control. The combination of NH 4 SCN+Aspergillus significantly enhanced the Cu-accumulation in leaves (228%); whereas NH 4 SCN+ Aspergillus, or (NH 4 ) 2 S 2 O 3 + Aspergillus resulted in greater accumulation of Cu in stems (1233.5% and 1580%, respectively) than the control. Results suggest that either NH 4 SCN or (NH 4 ) 2 S 2 O 3 (with or without Aspergillus) improved the accumulation of Au and Ag by B. napus. Accumulation of Au and Ag in plant organs overpassed the hyperaccumulation criterion (> 1 mg kg -1 of plant biomass); whereas Cu-accumulation in stems and roots also overpassed such criterion (> 1000 mg kg -1 ) by applying either NH 4 SCN or (NH 4 ) 2 S 2 O 3 + A. niger. Copyright © 2018 Elsevier Inc. All rights reserved.

Global, Daily, Near Real-Time Satellite-based Flood Monitoring and Product Dissemination

NASA Astrophysics Data System (ADS)

Slayback, D. A.; Policelli, F. S.; Brakenridge, G. R.; Tokay, M. M.; Smith, M. M.; Kettner, A. J.

2013-12-01

Flooding is the most destructive, frequent, and costly natural disaster faced by modern society, and is expected to increase in frequency and damage with climate change and population growth. Some of 2013's major floods have impacted the New York City region, the Midwest, Alberta, Australia, various parts of China, Thailand, Pakistan, and central Europe. The toll of these events, in financial costs, displacement of individuals, and deaths, is substantial and continues to rise as climate change generates more extreme weather events. When these events do occur, the disaster management community requires frequently updated and easily accessible information to better understand the extent of flooding and better coordinate response efforts. With funding from NASA's Applied Sciences program, we developed and are now operating a near real-time global flood mapping system to help provide critical flood extent information within 24-48 hours of events. The system applies a water detection algorithm to MODIS imagery received from the LANCE (Land Atmosphere Near real-time Capability for EOS) system at NASA Goddard within a few hours of satellite overpass. Using imagery from both the Terra (10:30 AM local time overpass) and Aqua (1:30 PM) platforms allows an initial daily assessment of flooding extent by late afternoon, and more robust assessments after accumulating cloud-free imagery over several days. Cloud cover is the primary limitation in detecting surface water from MODIS imagery. Other issues include the relatively coarse scale of the MODIS imagery (250 meters), the difficulty of detecting flood waters in areas with continuous canopy cover, confusion of shadow (cloud or terrain) with water, and accurately identifying detected water as flood as opposed to normal water extents. We have made progress on many of these issues, and are working to develop higher resolution flood detection using alternate sensors, including Landsat and various radar sensors. Although these provide better spatial resolution, this typically comes at the cost of being less timely. Since late 2011, this system has been providing daily flood maps of the global non-antarctic land surface. These data products are generated in raster and vector formats, and provided freely on our website. To better serve the disaster response community, we have recently begun providing the products via live OGC (Open Geospatial Consortium) services, allowing easy access in a variety of platforms (Google Earth, desktop GIS software, mobile phone apps). We are also working with the Pacific Disaster Center to bring our product into their Disaster Alert system (including a mobile app), which will help simplify product distribution to the disaster management community.

Estimating Daily Evapotranspiration Based on A Model of Evapotranspiration Fraction (EF) for Mixed Pixels

NASA Astrophysics Data System (ADS)

Xin, X.; Li, F.; Peng, Z.; Qinhuo, L.

2017-12-01

Land surface heterogeneities significantly affect the reliability and accuracy of remotely sensed evapotranspiration (ET), and it gets worse for lower resolution data. At the same time, temporal scale extrapolation of the instantaneous latent heat flux (LE) at satellite overpass time to daily ET are crucial for applications of such remote sensing product. The purpose of this paper is to propose a simple but efficient model for estimating daytime evapotranspiration considering heterogeneity of mixed pixels. In order to do so, an equation to calculate evapotranspiration fraction (EF) of mixed pixels was derived based on two key assumptions. Assumption 1: the available energy (AE) of each sub-pixel equals approximately to that of any other sub-pixels in the same mixed pixel within acceptable margin of bias, and as same as the AE of the mixed pixel. It's only for a simpification of the equation, and its uncertainties and resulted errors in estimated ET are very small. Assumption 2: EF of each sub-pixel equals to the EF of the nearest pure pixel(s) of same land cover type. This equation is supposed to be capable of correcting the spatial scale error of the mixed pixels EF and can be used to calculated daily ET with daily AE data.The model was applied to an artificial oasis in the midstream of Heihe River. HJ-1B satellite data were used to estimate the lumped fluxes at the scale of 300 m after resampling the 30-m resolution datasets to 300 m resolution, which was used to carry on the key step of the model. The results before and after correction were compare to each other and validated using site data of eddy-correlation systems. Results indicated that the new model is capable of improving accuracy of daily ET estimation relative to the lumped method. Validations at 12 sites of eddy-correlation systems for 9 days of HJ-1B overpass showed that the R² increased to 0.82 from 0.62; the RMSE decreased to 1.60 MJ/m² from 2.47MJ/m²; the MBE decreased from 1.92 MJ/m² to 1.18MJ/m², which is a quite significant enhancement.The model is easy to apply. And the moduler of inhomogeneous surfaces is independent and easy to be embedded in the traditional remote sensing algorithms of heat fluxes to get daily ET, which were mainly designed to calculate LE or ET under unsaturated conditions and did not consider heterogeneities of land surface.

The potential of satellite spectro-imagery for monitoring CO2 emissions from large cities

NASA Astrophysics Data System (ADS)

Broquet, Grégoire; Bréon, François-Marie; Renault, Emmanuel; Buchwitz, Michael; Reuter, Maximilian; Bovensmann, Heinrich; Chevallier, Frédéric; Wu, Lin; Ciais, Philippe

2018-02-01

This study assesses the potential of 2 to 10 km resolution imagery of CO2 concentrations retrieved from the shortwave infrared measurements of a space-borne passive spectrometer for monitoring the spatially integrated emissions from the Paris area. Such imagery could be provided by missions similar to CarbonSat, which was studied as a candidate Earth Explorer 8 mission by the European Space Agency (ESA). This assessment is based on observing system simulation experiments (OSSEs) with an atmospheric inversion approach at city scale. The inversion system solves for hourly city CO2 emissions and natural fluxes, or for these fluxes per main anthropogenic sector or ecosystem, during the 6 h before a given satellite overpass. These 6 h correspond to the period during which emissions produce CO2 plumes that can be identified on the image from this overpass. The statistical framework of the inversion accounts for the existence of some prior knowledge with 50 % uncertainty on the hourly or sectorial emissions, and with ˜ 25 % uncertainty on the 6 h mean emissions, from an inventory based on energy use and carbon fuel consumption statistics. The link between the hourly or sectorial emissions and the vertically integrated column of CO2 observed by the satellite is simulated using a coupled flux and atmospheric transport model. This coupled model is built with the information on the spatial and temporal distribution of emissions from the emission inventory produced by the local air-quality agency (Airparif) and a 2 km horizontal resolution atmospheric transport model. Tests are conducted for different realistic simulations of the spatial coverage, resolution, precision and accuracy of the imagery from sun-synchronous polar-orbiting missions, corresponding to the specifications of CarbonSat and Sentinel-5 or extrapolated from these specifications. First, OSSEs are conducted with a rather optimistic configuration in which the inversion system is perfectly informed about the statistics of the limited number of error sources. These OSSEs indicate that the image resolution has to be finer than 4 km to decrease the uncertainty in the 6 h mean emissions by more than 50 %. More complex experiments assess the impact of more realistic error estimates that current inversion methods do not properly account for, in particular, the systematic measurement errors with spatially correlated patterns. These experiments highlight the difficulty to improve current knowledge on CO2 emissions for urban areas like Paris with CO2 observations from satellites, and call for more technological innovations in the remote sensing of vertically integrated columns of CO2 and in the inversion systems that exploit it.

Metagenomic assessment of the interplay between the environment and the genetic diversification of Acinetobacter

PubMed Central

Touchon, Marie; Brisse, Sylvain; Rocha, Eduardo P.C.

2017-01-01

Summary Most bacteria have poorly characterized environmental reservoirs and unknown closely related species. This hampers the study of bacterial evolutionary ecology because both the environment and the genetic background of ancestral lineages are unknown. We combined metagenomics, comparative genomics and phylogenomics to overcome this limitation, to identify novel taxa and to propose environments where they can be isolated. We applied this method to characterize the ecological distribution of known and novel lineages of Acinetobacter spp. We observed two major environmental transitions at deep phylogenetic levels, splitting the genus into three ecologically differentiated clades. One of these has rapidly shifted towards host‐association by acquiring genes involved in bacteria‐eukaryote interactions. We show that environmental perturbations affect species distribution in predictable ways: bovines have very diverse communities of Acinetobacter, unless they were administered antibiotics, in which case they show highly uniform communities of Acinetobacter spp. that resemble those of humans. Our results uncover the diversity of bacterial lineages, overpassing the limitations of classical cultivation methods and highlight the role of the environment in shaping their evolution. PMID:28967182

Imager-to-Radiometer In-flight Cross Calibration: RSP Radiometric Comparison with Airborne and Satellite Sensors

NASA Technical Reports Server (NTRS)

McCorkel, Joel; Cairns, Brian; Wasilewski, Andrzej

2016-01-01

This work develops a method to compare the radiometric calibration between a radiometer and imagers hosted on aircraft and satellites. The radiometer is the airborne Research Scanning Polarimeter (RSP), which takes multi-angle, photo-polarimetric measurements in several spectral channels. The RSP measurements used in this work were coincident with measurements made by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), which was on the same aircraft. These airborne measurements were also coincident with an overpass of the Landsat 8 Operational Land Imager (OLI). First we compare the RSP and OLI radiance measurements to AVIRIS since the spectral response of the multispectral instruments can be used to synthesize a spectrally equivalent signal from the imaging spectrometer data. We then explore a method that uses AVIRIS as a transfer between RSP and OLI to show that radiometric traceability of a satellite-based imager can be used to calibrate a radiometer despite differences in spectral channel sensitivities. This calibration transfer shows agreement within the uncertainty of both the various instruments for most spectral channels.

Distinguishing vegetation from soil background information. [by gray mapping of Landsat MSS data

NASA Technical Reports Server (NTRS)

Richardson, A. J.; Wiegand, C. L.

1977-01-01

In aircraft and satellite multispectral scanner data, soil background signals are superimposed on or intermingled with information about vegetation. A procedure which accounts for soil background would, therefore, make a considerable contribution to an operational use of Landsat and other spectral data for monitoring the productivity of range, forest, and crop lands. A description is presented of an investigation which was conducted to obtain information for the development of such a procedure. The investigation included a study of the soil reflectance that supplies the background signal of vegetated surfaces. Landsat data as recorded on computer compatible tapes were used in the study. The results of the investigation are discussed, taking into account a study reported by Kauth and Thomas (1976). Attention is given to the determination of Kauth's plane of soils, sun angle effects, vegetation index modeling, and the evaluation of vegetation indexes. Graphs are presented which show the results obtained with a gray mapping technique. The technique makes it possible to display plant, soil, water, and cloud conditions for any Landsat overpass.

Retrieval with Infrared Atmospheric Sounding Interferometer and Validation during JAIVEx

NASA Technical Reports Server (NTRS)

Zhou, Daniel K.; Liu, Xu; Larar, Allen M.; Smith, William L.; Taylor, Jonathan P.; Schluessel, Peter; Strow, L. Larrabee; Mango, Stephen A.

2008-01-01

A state-of-the-art IR-only retrieval algorithm has been developed with an all-season-global EOF Physical Regression and followed by 1-D Var. Physical Iterative Retrieval for IASI, AIRS, and NAST-I. The benefits of this retrieval are to produce atmospheric structure with a single FOV horizontal resolution (approx. 15 km for IASI and AIRS), accurate profiles above the cloud (at least) or down to the surface, surface parameters, and/or cloud microphysical parameters. Initial case study and validation indicates that surface, cloud, and atmospheric structure (include TBL) are well captured by IASI and AIRS measurements. Coincident dropsondes during the IASI and AIRS overpasses are used to validate atmospheric conditions, and accurate retrievals are obtained with an expected vertical resolution. JAIVEx has provided the data needed to validate the retrieval algorithm and its products which allows us to assess the instrument ability and/or performance. Retrievals with global coverage are under investigation for detailed retrieval assessment. It is greatly desired that these products be used for testing the impact on Atmospheric Data Assimilation and/or Numerical Weather Prediction.

Long time-series of turbid coastal water using AVHRR: An example from Florida Bay, USA

USGS Publications Warehouse

Stumpf, R.P.; Frayer, M.L.

1997-01-01

The AVHRR can provide information on the reflectance of turbid case II water, permitting examination of large estuaries and plumes from major rivers. The AVHRR has been onboard several NOAA satellites, with afternoon overpasses since 1981, offering a long time-series to examine changes in coastal water. We are using AVHRR data starting in December 1989, to examine water clarity in Florida Bay, which has undergone a decline since the late 1980's. The processing involves obtaining a nominal reflectance for red light with standard corrections including those for Rayleigh and aerosol path radiances. Established relationships between reflectance and the water properties being measured in the Bay provide estimates of diffuse attenuation and light limitation for phytoplankton and seagrass productivity studies. Processing also includes monthly averages of reflectance and attenuation. The AVHRR data set describes spatial and temporal patterns, including resuspension of bottom sediments in the winter, and changes in water clarity. The AVHRR also indicates that Florida Bay has much higher reflectivity relative to attenuation than other southeastern US estuaries. ??2005 Copyright SPIE - The International Society for Optical Engineering.

Vegetation Water Content Mapping for Agricultural Regions in SMAPVEX16

NASA Astrophysics Data System (ADS)

White, W. A.; Cosh, M. H.; McKee, L.; Berg, A. A.; McNairn, H.; Hornbuckle, B. K.; Colliander, A.; Jackson, T. J.

2017-12-01

Vegetation water content impacts the ability of L-band radiometers to measure surface soil moisture. Therefore it is necessary to quantify the amount of water held in surface vegetation for an accurate soil moisture remote sensing retrieval. A methodology is presented for generating agricultural vegetation water content maps using Landsat 8 scenes for agricultural fields of Iowa and Manitoba for the Soil Moisture Active Passive Validation Experiments in 2016 (SMAPVEX16). Manitoba has a variety of row crops across the region, and the study period encompasses the time frame from emergence to reproduction, as well as a forested region. The Iowa study site is dominated by corn and soybeans, presenting an easier challenge. Ground collection of vegetation biomass and water content were also collected to provide a ground truth data source. Errors for the resulting vegetation water content maps ranged depending upon crop type, but generally were less than 15% of the total plant water content per crop type. Interpolation is done between Landsat overpasses to produce daily vegetation water content maps for the summer of 2016 at a 30 meter resolution.

Hand-held radiometry: A set of notes developed for use at the Workshop of Hand-held radiometry

NASA Technical Reports Server (NTRS)

Jackson, R. D.; Pinter, P. J., Jr.; Reginato, R. J.; Idso, S. B. (Principal Investigator)

1980-01-01

A set of notes was developed to aid the beginner in hand-held radiometry. The electromagnetic spectrum is reviewed, and pertinent terms are defined. View areas of multiband radiometers are developed to show the areas of coincidence of adjacent bands. The amounts of plant cover seen by radiometers having different fields of view are described. Vegetation indices are derived and discussed. Response functions of several radiometers are shown and applied to spectrometer data taken over 12 wheat plots, to provide a comparison of instruments and bands within and among instruments. The calculation of solar time is reviewed and applied to the calculation of the local time of LANDSAT satellite overpasses for any particular location in the Northern Hemisphere. The use and misuse of hand-held infrared thermometers are discussed, and a procedure for photographic determination of plant cover is described. Some suggestions are offered concerning procedures to be followed when collecting hand-held spectral and thermal data. A list of references pertinent to hand-held radiometry is included.

Fire and Smoke in Western Russia on August 4, 2010

NASA Image and Video Library

2017-12-08

NASA image acquired August 4, 2010 Intense fires continued to rage in western Russia on August 4, 2010. Burning in dry peat bogs and forests, the fires produced a dense plume of smoke that reached across hundreds of kilometers. The Moderate Resolution Imaging Spectroradiometer (MODIS) captured this view of the fires and smoke in three consecutive overpasses on NASA’s Terra satellite. The smooth gray-brown smoke hangs over the Russian landscape, completely obscuring the ground in places. The top image provides a close view of the fires immediately southeast of Moscow, while the lower image shows the full extent of the smoke plume. To read more about this image go to: earthobservatory.nasa.gov/IOTD/view.php?id=45046 To view the high res go here: NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC. NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Evaluation of Dynamic Passing Sight Distance Problem Using a Finite Element Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Xuedong; Radwan, Essam; Zhang, Fan

2008-06-01

Sufficient passing sight distance is an important control for two-lane rural highway design to minimize the possibility of a head-on collision between passing and opposing vehicles. Traditionally, passing zones are marked by checking passing sight distance that is potentially restricted by static sight obstructions. Such obstructions include crest curves, overpasses, and lateral objects along highways. This paper proposes a new concept of dynamic sight-distance assessment, which involves restricted passing sight distances due to the impeding vehicles that are traveling in the same direction. Using a finite-element model, the dynamic passing sight-distance problem was evaluated, and the writers analyzed the relationshipsmore » between the available passing sight distance and other factors such as the horizontal curve radius, impeding vehicle dimensions, and a driver s following distance. It was found that the impeding vehicles may cause substantially insufficient passing sight distances, which may lead to potential traffic safety problems. It is worthwhile to expand on this safety issue and consider the dynamic passing sight distance in highway design.« less

The Experimental Cloud Lidar Pilot Study (ECLIPS) for cloud-radiation research

NASA Technical Reports Server (NTRS)

Platt, C. M.; Young, S. A.; Carswell, A. I.; Pal, S. R.; Mccormick, M. P.; Winker, D. M.; Delguasta, M.; Stefanutti, L.; Eberhard, W. L.; Hardesty, M.

1994-01-01

The Experimental Cloud Lidar Pilot Study (ECLIPS) was initiated to obtain statistics on cloud-base height, extinction, optical depth, cloud brokenness, and surface fluxes. Two observational phases have taken place, in October-December 1989 and April-July 1991, with intensive 30-day periods being selected within the two time intervals. Data are being archived at NASA Langley Research Center and, once there, are readily available to the international scientific community. This article describes the scale of the study in terms of its international involvement and in the range of data being recorded. Lidar observations of cloud height and backscatter coefficient have been taken from a number of ground-based stations spread around the globe. Solar shortwave and infrared longwave fluxes and infrared beam radiance have been measured at the surface wherever possible. The observations have been tailored to occur around the overpass times of the NOAA weather satellites. This article describes in some detail the various retrieval methods used to obtain results on cloud-base height, extinction coefficient, and infrared emittance, paying particular attention to the uncertainties involved.

Multilevel measurements of surface temperature over undulating terrain planted to barley

NASA Technical Reports Server (NTRS)

Reginato, R. J. (Principal Investigator); Millard, J. P.; Hatfield, J. L.; Jackson, R. D.

1981-01-01

A ground and aircraft program was conducted to extend ground based methods for measuring soil moisture and crop water stress to aircraft and satellite altitudes. A 260ha agricultural field in California was used over the 1977-78 growing season. For cloud free days ground based temperature measurements over bare soil were related to soil moisture content. Water stress resulted from too much water, not from lack of it, as was expected. A theoretical examination of the canopy air temperature difference as affected by vapor pressure deficit and net radiation was developed. This analysis shows why surface temperatures delineate crop water stress under conditions of low humidity, but not under high humidity conditions. Multilevel temperatures acquired from the ground, low and high altitude aircraft, and the Heat Capacity Mapping Mission (HCMM) spacecraft were compared for two day and one night overpasses. The U-2 and low altitude temperatures were within 0.5 C. The HCMM data were analyzed using both the pre- and post-launch calibrations, with the former being considerably closer in agreement with the aircraft data than the latter.

Influences of high-flow events on a stream channel altered by construction of a highway bridge: A case study

USGS Publications Warehouse

Hedrick, Lara B.; Welsh, Stuart A.; Anderson, James T.

2009-01-01

Impacts of highway construction on streams in the central Appalachians are a growing concern as new roads are created to promote tourism and economic development in the area. Alterations to the streambed of a first-order stream, Sauerkraut Run, Hardy County, WV, during construction of a highway overpass included placement and removal of a temporary culvert, straightening and regrading of a section of stream channel, and armourment of a bank with a reinforced gravel berm. We surveyed longitudinal profiles and cross sections in a reference reach and the altered reach of Sauerkraut Run from 2003 through 2007 to measure physical changes in the streambed. During the four-year period, three high-flow events changed the streambed downstream of construction including channel widening and aggradation and then degradation of the streambed. Upstream of construction, at a reinforced gravel berm, bank erosion was documented. The reference section remained relatively unchanged. Knowledge gained by documenting channel changes in response to natural and anthropogenic variables can be useful for managers and engineers involved in highway construction projects.

Exploitation of multi-temporal Earth Observation imagery for monitoring land cover change in mining sites

NASA Astrophysics Data System (ADS)

Petropoulos, G.; Partsinevelos, P.; Mitraka, Z.

2012-04-01

Surface mining has been shown to cause intensive environmental degradation in terms of landscape, vegetation and biological communities. Nowadays, the commercial availability of remote sensing imagery at high spatiotemporal scales, has improved dramatically our ability to monitor surface mining activity and evaluate its impact on the environment and society. In this study we investigate the potential use of Landsat TM imagery combined with diverse classification techniques, namely artificial neural networks and support vector machines for delineating mining exploration and assessing its effect on vegetation in various surface mining sites in the Greek island of Milos. Assessment of the mining impact in the study area is validated through the analysis of available QuickBird imagery acquired nearly concurrently to the TM overpasses. Results indicate the capability of the TM sensor combined with the image analysis applied herein as a potential economically viable solution to provide rapidly and at regular time intervals information on mining activity and its impact to the local environment. KEYWORDS: mining environmental impact, remote sensing, image classification, change detection, land reclamation, support vector machines, neural networks

Fire and Smoke in Western Russia on August 4, 2010 [high res

NASA Image and Video Library

2017-12-08

NASA image acquired August 4, 2010 Intense fires continued to rage in western Russia on August 4, 2010. Burning in dry peat bogs and forests, the fires produced a dense plume of smoke that reached across hundreds of kilometers. The Moderate Resolution Imaging Spectroradiometer (MODIS) captured this view of the fires and smoke in three consecutive overpasses on NASA’s Terra satellite. The smooth gray-brown smoke hangs over the Russian landscape, completely obscuring the ground in places. The top image provides a close view of the fires immediately southeast of Moscow, while the lower image shows the full extent of the smoke plume. To read more about this image go to: earthobservatory.nasa.gov/IOTD/view.php?id=45046 NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC. NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Hydrological impacts of urbanization at the catchment scale

NASA Astrophysics Data System (ADS)

Oudin, Ludovic; Salavati, Bahar; Furusho-Percot, Carina; Ribstein, Pierre; Saadi, Mohamed

2018-04-01

The impacts of urbanization on floods, droughts and the overall river regime have been largely investigated in the past few decades, but the quantification and the prediction of such impacts still remain a challenge in hydrology. We gathered a sample of 142 catchments that have a documented increase in urban areas over the hydrometeorological record period in the United States. The changes in river flow regimes due to urban spread were differentiated from climate variability using the GR4J conceptual hydrological model. High, low and mean flows were impacted at a threshold of a 10% total impervious area. Moreover, the historical evolution of urban landscape spatial patterns was used to further detail the urbanization process in terms of extent and fragmentation of urban areas throughout the catchment and to help interpret the divergent impacts observed in streamflow behaviors. Regression analysis pointed out the importance of major wastewater treatment facilities that might overpass the effects of imperviousness, and therefore further research should either take them explicitly into account or select a wastewater facility-free catchment sample to clearly evaluate the impacts of urban landscape on low flows.

Oil-pollution detection and monitoring from space using ERTS-1

NASA Technical Reports Server (NTRS)

Horvath, R.; Goldman, G. C. (Principal Investigator)

1975-01-01

The author has identified the following significant results. Three reported spills were investigated using four digital computer, compatible techniques on ERTS - 1 data. A spill on the Atlantic Ocean (off Virginia) was studied to develop spectral signatures. Another spill, in Oakland Bay, was studied by ratioing spectral channels (to try to eliminate turbidity effects) and by summing different spectral channels to look for anomolus values caused by oil. The final spill, off Southern California, was investigated by looking for anomolus values in each channel separately. Results indicate that any of these methods might be usable if the spill is large enough to be seen by satellite, if the spill occurs more than a few kilometers off shore, and if the sky and water are relatively clear. In the case of the Atlantic spill, identification of material was not possible; and in the other two cases, the spills could not be detected at all. ERTS-1 was not considered feasible for this type of work because of its 18 day overpass frequency, the few spectral channels, the extended bandwidths, and the long, information retrieval time.

Minimally invasive surgical treatment of malignant pleural effusions.

PubMed

Ciuche, Adrian; Nistor, Claudiu; Pantile, Daniel; Prof Horvat, Teodor

2011-10-01

Usually the pleural cavity contains a small amount of liquid (approximately 10 ml). Pleural effusions appear when the liquid production rate overpasses the absorption rate with a greater amount of liquid inside the pleural cavity. Between January 1998 to December 2008 we conducted a study in order to establish the adequate surgical treatment for MPEs. Effective control of a recurrent malignant pleural effusion can greatly improve the quality of life of the cancer patient. The present review collects and examines the clinical results of minimally invasive techniques designed to treat this problem. Patients with MPEs were studied according to several criteria. In our study we observed the superiority of intraoperative talc poudrage, probably due to a more uniform distribution of talc particles over the pleural surface. Minimal pleurotomy with thoracic drainage and instillation of a talc suspension is also a safe and effective technique and should be employed when there are contraindications for the thoracoscopic minimally invasive procedure. On the basis of comparisons involving effectiveness, morbidity, and convenience, we recommend the thoracoscopic insufflations of talc as a fine powder with pleural drainage as the procedure of choice.

NASA's Global Imagery Browse Services: Past, Present and Future

NASA Astrophysics Data System (ADS)

Baynes, K.; Boller, R. A.; Roberts, J. T.; Cechini, M. F.; Alarcon, C.; Pilone, D.

2016-12-01

NASA's Global Imagery Browse Services (GIBS) provides quick access to almost 500 satellite imagery products, covering every part of the world in a free, open, and interoperable manner. Much of the imagery is available with a few hours after satellite overpass and some products span over 15 years. This imagery has been used for a diverse array of applications including wildfire monitoring, air quality research, education, and soaring above the Earth through immersive planetarium shows. In addition to describing GIBS and its origins and showcasing these applications, this talk will describe the process of how new layers are integrated into the system through interfacing with data providers, how the GIBS team has evolved use cases from the community for new functionality, such as vector data and vertical profile information, and how the GIBS team is pushing forward with research and development aimed at bringing data and imagery together in a seamless manner. Finally, we will discuss new layers currently being integrated into the system and an on-going prototype to evolve the system into a cloud environment.

Seasonal LAI in slash pine estimated with LANDSAT TM

NASA Technical Reports Server (NTRS)

Curran, Paul J.; Dungan, Jennifer L.; Gholz, Henry L.

1990-01-01

The leaf area index (LAI, total area of leaves per unit area of ground) of most forest canopies varies throughout the year, yet for logistical reasons it is difficult to estimate anything more detailed than a seasonal maximum LAI. To determine if remotely sensed data can be used to estimate LAI seasonally, field measurements of LAI were compared to normalized difference vegetation index (NDVI) values derived using LANDSAT Thematic Mapper (TM) data, for 16 fertilized and control slash pine plots on 3 dates. Linear relationships existed between NDVI and LAI with R(sup 2) values of 0.35, 0.75, and 0.86 for February 1988, September 1988, and March, 1989, respectively. This is the first reported study in which NDVI is related to forest LAI recorded during the month of sensor overpass. Predictive relationships based on data from eight of the plots were used to estimate the LAI of the other eight plots with a root-mean-square error of 0.74 LAI, which is 15.6 percent of the mean LAI. This demonstrates the potential use of LANDSAT TM data for studying seasonal dynamics in forest canopies.

Classification and soil moisture determination of agricultural fields

NASA Technical Reports Server (NTRS)

Vandenbroek, A. C.; Groot, J. S.

1993-01-01

During the Mac-Europe campaign of 1991 several SAR (Synthetic Aperature Radar) experiments were carried out in the Flevoland test area in the Netherlands. The test site consists of a forested and an agricultural area with more than 15 different crop types. The experiments took place in June and July (mid to late growing season). The area was monitored by the spaceborne C-band VV polarized ERS-1, the Dutch airborne PHARS with similar frequency and polarization and the three-frequency PP-, L-, and C-band) polarimetric AIRSAR system of NASA/JPL. The last system passed over on June 15, 3, 12, and 28. The last two dates coincided with the overpasses of the PHARS and the ERS-1. Comparison of the results showed that backscattering coefficients from the three systems agree quite well. In this paper we present the results of a study of crop type classification (section 2) and soil moisture determination in the agricultural area (section 3). For these studies we used field averaged Stokes matrices extracted from the AIRSAR data (processor version 3.55 or 3.56).

Evaluation of NCMRWF unified model vertical cloud structure with CloudSat over the Indian summer monsoon region

NASA Astrophysics Data System (ADS)

Jayakumar, A.; Mamgain, Ashu; Jisesh, A. S.; Mohandas, Saji; Rakhi, R.; Rajagopal, E. N.

2016-05-01

Representation of rainfall distribution and monsoon circulation in the high resolution versions of NCMRWF Unified model (NCUM-REG) for the short-range forecasting of extreme rainfall event is vastly dependent on the key factors such as vertical cloud distribution, convection and convection/cloud relationship in the model. Hence it is highly relevant to evaluate the vertical structure of cloud and precipitation of the model over the monsoon environment. In this regard, we utilized the synergy of the capabilities of CloudSat data for long observational period, by conditioning it for the synoptic situation of the model simulation period. Simulations were run at 4-km grid length with the convective parameterization effectively switched off and on. Since the sample of CloudSat overpasses through the monsoon domain is small, the aforementioned methodology may qualitatively evaluate the vertical cloud structure for the model simulation period. It is envisaged that the present study will open up the possibility of further improvement in the high resolution version of NCUM in the tropics for the Indian summer monsoon associated rainfall events.

Modelling of wildlife migrations and its economic impacts

NASA Astrophysics Data System (ADS)

Myšková, Kateřina; Žák, Jaroslav

2013-10-01

Natural wildlife migrations are often disrupted by the construction of line structures, especially freeways. Various overpasses and underpasses (migration objects) are being designed to enable species to pass through line structures. The newly developed original procedure for the quantification of the utility of migration objects (migration potentials) and sections of line structures retrieves the deficiencies of the previous ones. The procedure has been developed under bulk information obtained by monitoring migrations using camera system and spy games. The log-normal distribution functions are used. The procedure for the evaluation of the probability of the permeability of the line structures sectors is also presented. The above mentioned procedures and algorithms can be used while planning, preparing, constructing or verifying the measures to assure the permeability of line structures for selected feral species. Using the procedures can significantly reduce financial costs and improve the permeability. When the migration potentials are correctly determined and the whole sector is taken into account for the migrations, some originally designed objects may be found to be redundant and not building them will bring financial savings.

Long time-series of turbid coastal water using AVHRR: an example from Florida Bay, USA

NASA Astrophysics Data System (ADS)

Stumpf, Richard P.; Frayer, M. L.

1997-02-01

The AVHRR can provide information on the reflectance of turbid case II water, permitting examination of large estuaries and plumes from major rivers. The AVHRR has been onboard several NOAA satellites, with afternoon overpasses since 1981, offering a long time-series to examine changes in coastal water. We are using AVHRR data starting in December 1989, to examine water clarity in Florida Bay, which has undergone a decline since the late 1980's. The processing involves obtaining a nominal reflectance for red light with standard corrections including those for Rayleigh and aerosol path radiances. Established relationships between reflectance and the water properties being measured in the Bay provide estimates of diffuse attenuation and light limitation for phytoplankton and seagrass productivity studies. Processing also includes monthly averages of reflectance and attenuation. The AVHRR data set describes spatial and temporal patterns, including resuspension of bottom sediments in the winter, and changes in water clarity. The AVHRR also indicates that Florida Bay has much higher reflectivity relative to attenuation than other southeastern US estuaries.

Validation of Sentinel-3A altimetry data by using in-situ multi-platform observations near Mallorca Island (western Mediterranean)

NASA Astrophysics Data System (ADS)

Sánchez-Román, Antonio; Heslop, Emma; Reeve, Krissy; Rodriguez, Daniel; Pujol, Isabelle; Faugère, Yannice; Torner, Marc; Tintoré, Joaquín; Pascual, Ananda

2017-04-01

In the frame of the Copernicus Marine Environment Monitoring Service (CMEMS) Sea Level Thematic Assembly Center (SL-TAC), a glider mission was undertaken between May and June 2016 along the same track as the overpass of the Sentinel 3A satellite in the Southern Mallorca region. Moreover, a one-day ship mission on May 30, synchronous with the overpass of the satellite, captured two transects of moving vessel ADCP close to the coastal area. The aim was to compare the along track altimeter products and multi-platform in-situ observations in the southern coastal zone of the Mallorca Island and the Algerian Basin. In addition, we explored the potential of the Synthetic Aperture Radar Mode (SARM) instrumentation of Sentinel-3 mission, which enables the satellite to measure nearest the coasts with both higher spatial resolution and higher precision than previous missions. With the ultimate goal of contributing to a more complete understanding of both ocean and coastal physical processes and the biogeochemical impacts. The analyses presented here are conducted through the comparison of Absolute Dynamic Topography (ADT) obtained from the Sentinel-3A altimetry measurements along ground-track #713 and Dynamic Height (DH) derived from temperature and salinity profiles measured by the glider along the trajectory followed by the satellite. Moreover, currents derived from altimetry and in-situ glider data along the track followed by the satellite; and from ADCP data collected in the coastal region are analysed. Results show a good agreement between ADT from altimetry and DH from glider data with maximum differences of around 2 cm that promote a root mean square error (RMSE) of 1 cm, the correlation coefficient between both datasets is 0.89. The satellite data closely resemble the geostrophic velocity pattern observed by the glider measurements along the Algerian Current, and also the ADCP data in the coastal zone, exhibiting a RMSE lower than 10 cm/s and a correlation coefficient larger than 0.75. This mission is part of a study focused on mesoscale variability and comparison of the along-track and gridded interpolated maps altimetry products in the western Mediterranean Sea using in-situ data including Argo, ADCP, gliders, drifters, HF radar and tide gauges data. We take advantage of the high spatial resolution and a multi-platform approach to investigate the variability of physical processes in the coastal area of this region. This experiment contributes to the preparatory cal/val activities of the forthcoming wide-swath satellite altimeter (SWOT) that will provide daily high resolution sea surface height measurements during the fast phase after launch around the Balearic Islands.

Global Near Real-Time Satellite-based Flood Monitoring and Product Dissemination

NASA Astrophysics Data System (ADS)

Smith, M.; Slayback, D. A.; Policelli, F.; Brakenridge, G. R.; Tokay, M.

2012-12-01

Flooding is among the most destructive, frequent, and costly natural disasters faced by modern society, with several major events occurring each year. In the past few years, major floods have devastated parts of China, Thailand, Pakistan, Australia, and the Philippines, among others. The toll of these events, in financial costs, displacement of individuals, and deaths, is substantial and continues to rise as climate change generates more extreme weather events. When these events do occur, the disaster management community requires frequently updated and easily accessible information to better understand the extent of flooding and better coordinate response efforts. With funding from NASA's Applied Sciences program, we have developed, and are now operating, a near real-time global flood mapping system to help provide critical flood extent information within 24-48 hours after flooding events. The system applies a water detection algorithm to MODIS imagery received from the LANCE (Land Atmosphere Near real-time Capability for EOS) system at NASA Goddard. The LANCE system typically processes imagery in less than 3 hours after satellite overpass, and our flood mapping system can output flood products within ½ hour of acquiring the LANCE products. Using imagery from both the Terra (10:30 AM local time overpass) and Aqua (1:30 PM) platforms allows an initial assessment of flooding extent by late afternoon, every day, and more robust assessments after accumulating imagery over a longer period; the MODIS sensors are optical, so cloud cover remains an issue, which is partly overcome by using multiple looks over one or more days. Other issues include the relatively coarse scale of the MODIS imagery (250 meters), the difficulty of detecting flood waters in areas with continuous canopy cover, confusion of shadow (cloud or terrain) with water, and accurately identifying detected water as flood as opposed to normal water extents. We have made progress on some of these issues, and are working to develop higher resolution flood detection using alternate sensors, including Landsat and various radar sensors. Although these provide better spatial resolution, this comes at the cost of being less timely. As of late 2011, the system expanded to fully global daily flood monitoring, with free public access to the generated products. These include GIS-ready files of flood and normal water extent (KML, shapefile, raster), and small scale graphic maps (10 degrees square) showing regional flood extent. We are now expanding product distribution channels to include live web services (WMS, etc), allowing easier access via standalone apps. We are also working to bring our product into the Pacific Disaster Center's Disaster Alert system and mobile app for wider accessibility.

MAX-DOAS NO2 observations over Guangzhou, China; ground-based and satellite comparisons

NASA Astrophysics Data System (ADS)

Drosoglou, Theano; Elissavet Koukouli, Maria; Kouremeti, Natalia; Bais, Alkiviadis F.; Zyrichidou, Irene; Balis, Dimitris; van der A, Ronald J.; Xu, Jin; Li, Ang

2018-04-01

In this study, the tropospheric NO2 vertical column density (VCD) over an urban site in Guangzhou megacity in China is investigated by means of MAX-DOAS measurements during a campaign from late March 2015 to mid-March 2016. A MAX-DOAS system was deployed at the Guangzhou Institute of Geochemistry of the Chinese Academy of Sciences and operated there for about 1 year, during the spring and summer months. The tropospheric NO2 VCDs retrieved by the MAX-DOAS are presented and compared with space-borne observations from GOME-2/MetOp-A, GOME-2/MetOp-B and OMI/Aura satellite sensors. The comparisons reveal good agreement between satellite and MAX-DOAS observations over Guangzhou, with correlation coefficients ranging between 0.795 for GOME-2B and 0.996 for OMI. However, the tropospheric NO2 loadings are underestimated by the satellite sensors on average by 25.1, 10.3 and 5.7 %, respectively, for OMI, GOME-2A and GOME-2B. Our results indicate that GOME-2B retrievals are closer to those of the MAX-DOAS instrument due to the lower tropospheric NO2 concentrations during the days with valid GOME-2B observations. In addition, the effect of the main coincidence criteria is investigated, namely the cloud fraction (CF), the distance (d) between the satellite pixel center and the ground-based measurement site, as well as the time period within which the MAX-DOAS data are averaged around the satellite overpass time. The effect of CF and time window criteria is more profound on the selection of OMI overpass data, probably due to its smaller pixel size. The available data pairs are reduced to half and about one-third for CF ≤ 0.3 and CF ≤ 0.2, respectively, while, compared to larger CF thresholds, the correlation coefficient is improved to 0.996 from about 0.86, the slope value is very close to unity ( ˜ 0.98) and the mean satellite underestimation is reduced to about half (from ˜ 7 to ˜ 3.5 × 1015 molecules cm-2). On the other hand, the distance criterion affects mostly GOME-2B data selection, because GOME-2B pixels are quite evenly distributed among the different radii used in the sensitivity test. More specifically, the number of collocations is notably reduced when stricter radius limits are applied, the r value is improved from 0.795 (d ≤ 50 km) to 0.953 (d ≤ 20 km), and the absolute mean bias decreases about 6 times for d ≤ 30 km compared to the reference case (d ≤ 50 km).

Accounting for aquifer heterogeneity from geological data to management tools.

PubMed

Blouin, Martin; Martel, Richard; Gloaguen, Erwan

2013-01-01

A nested workflow of multiple-point geostatistics (MPG) and sequential Gaussian simulation (SGS) was tested on a study area of 6 km(2) located about 20 km northwest of Quebec City, Canada. In order to assess its geological and hydrogeological parameter heterogeneity and to provide tools to evaluate uncertainties in aquifer management, direct and indirect field measurements are used as inputs in the geostatistical simulations to reproduce large and small-scale heterogeneities. To do so, the lithological information is first associated to equivalent hydrogeological facies (hydrofacies) according to hydraulic properties measured at several wells. Then, heterogeneous hydrofacies (HF) realizations are generated using a prior geological model as training image (TI) with the MPG algorithm. The hydraulic conductivity (K) heterogeneity modeling within each HF is finally computed using SGS algorithm. Different K models are integrated in a finite-element hydrogeological model to calculate multiple transport simulations. Different scenarios exhibit variations in mass transport path and dispersion associated with the large- and small-scale heterogeneity respectively. Three-dimensional maps showing the probability of overpassing different thresholds are presented as examples of management tools. © 2012, The Author(s). Groundwater © 2012, National Ground Water Association.

A method for mapping corn using the US Geological Survey 1992 National Land Cover Dataset

USGS Publications Warehouse

Maxwell, S.K.; Nuckols, J.R.; Ward, M.H.

2006-01-01

Long-term exposure to elevated nitrate levels in community drinking water supplies has been associated with an elevated risk of several cancers including non-Hodgkin's lymphoma, colon cancer, and bladder cancer. To estimate human exposure to nitrate, specific crop type information is needed as fertilizer application rates vary widely by crop type. Corn requires the highest application of nitrogen fertilizer of crops grown in the Midwest US. We developed a method to refine the US Geological Survey National Land Cover Dataset (NLCD) (including map and original Landsat images) to distinguish corn from other crops. Overall average agreement between the resulting corn and other row crops class and ground reference data was 0.79 kappa coefficient with individual Landsat images ranging from 0.46 to 0.93 kappa. The highest accuracies occurred in Regions where corn was the single dominant crop (greater than 80.0%) and the crop vegetation conditions at the time of image acquisition were optimum for separation of corn from all other crops. Factors that resulted in lower accuracies included the accuracy of the NLCD map, accuracy of corn areal estimates, crop mixture, crop condition at the time of Landsat overpass, and Landsat scene anomalies.

Satellite Ocean Color Validation Using Merchant Ships. Chapter 10

NASA Technical Reports Server (NTRS)

Frouin, Robert; Cutchin, David L.; Deschamps, Pierre-Yves

2001-01-01

A collaborative measurement program for evaluating satellite-derived ocean color has been developed based on ships of opportunity (merchant, oceanographic) and specific instrumentation, the SIMBAD radiometer. The purpose of the measurement program is to complement, in a cost-effective way, dedicated evaluation experiments at sea, which are expensive, cannot be carried out over the full range of expected oceanic and atmospheric conditions, and generally provide a few match-ups. Ships participate in the program on a volunteer basis or at a very small cost, and measurement procedures do not interfere with other ship activities. The SIMBAD radiometer is a portable, easy-to-operate instrument that measures the basic ocean color variables, namely aerosol optical thickness and water-leaving radiance, in typical spectral bands of ocean-color sensors, i.e., 443, 490, 560, 670, and 870 nm. Measuring these variables at the time of satellite overpass is usually sufficient to verify satellite-derived ocean color and to evaluate atmospheric correction algorithms. Any ordinary crew can learn quickly how to make measurements. Importantly, the ship is not required to stop, making it possible to collect data along regular routes traveled by merchant ships in the world's oceans.

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.

Validation of Suomi-NPP VIIRS sea ice concentration with very high-resolution satellite and airborne camera imagery

NASA Astrophysics Data System (ADS)

Baldwin, Daniel; Tschudi, Mark; Pacifici, Fabio; Liu, Yinghui

2017-08-01

Two independent VIIRS-based Sea Ice Concentration (SIC) products are validated against SIC as estimated from Very High Spatial Resolution Imagery for several VIIRS overpasses. The 375 m resolution VIIRS SIC from the Interface Data Processing Segment (IDPS) SIC algorithm is compared against estimates made from 2 m DigitalGlobe (DG) WorldView-2 imagery and also against estimates created from 10 cm Digital Mapping System (DMS) camera imagery. The 750 m VIIRS SIC from the Enterprise SIC algorithm is compared against DG imagery. The IDPS vs. DG comparisons reveal that, due to algorithm issues, many of the IDPS SIC retrievals were falsely assigned ice-free values when the pixel was clearly over ice. These false values increased the validation bias and RMS statistics. The IDPS vs. DMS comparisons were largely over ice-covered regions and did not demonstrate the false retrieval issue. The validation results show that products from both the IDPS and Enterprise algorithms were within or very close to the 10% accuracy (bias) specifications in both the non-melting and melting conditions, but only products from the Enterprise algorithm met the 25% specifications for the uncertainty (RMS).

Retina as Reciprocal Spatial Fourier Transform Space Implies ``Wave-transformation'' Functions, String Theory, the Inappropriate Uncertainty Principle, and Predicts ``Quarked'' Protons.

NASA Astrophysics Data System (ADS)

Mc Leod, Roger David; Mc Leod, David M.

2007-10-01

Vision, via transform space: ``Nature behaves in a reciprocal way;' also, Rect x pressure-input sense-reports as Sinc p, indicating brain interprets reciprocal ``p'' space as object space. Use Mott's and Sneddon's Wave Mechanics and Its Applications. Wave transformation functions are strings of positron, electron, proton, and neutron; uncertainty is a semantic artifact. Neutrino-string de Broglie-Schr"odinger wave-function models for electron, positron, suggest three-quark models for protons, neutrons. Variably vibrating neutrino-quills of this model, with appropriate mass-energy, can be a vertical proton string, quills leftward; thread string circumferentially, forming three interlinked circles with ``overpasses''. Diameters are 2:1:2, center circle has quills radially outward; call it a down quark, charge --1/3, charge 2/3 for outward quills, the up quarks of outer circles. String overlap summations are nodes; nodes also far left and right. Strong nuclear forces may be --px. ``Dislodging" positron with neutrino switches quark-circle configuration to 1:2:1, `downers' outside. Unstable neutron charge is 0. Atoms build. With scale factors, retinal/vision's, and quantum mechanics,' spatial Fourier transforms/inverses are equivalent.

JOVE

NASA Technical Reports Server (NTRS)

Schiller, Stephen

1997-01-01

The focus of our JOVE research has been to develop a field instrument that provides high quality data for atmospheric corrections and in-flight calibration of airborne and satellite remote sensing imaging systems. The instrument package is known as the Portable Ground-based Atmospheric Monitoring System or PGAMS. PGAMS collects a comprehensive set of spectroscopic/radiometric observations that describe the optical properties of the atmosphere and reflectance of a target area on the earth's surface at the time of the aircraft or satellite overpass. To date, the PGAMS instrument system and control software has been completed and used for data collection in several NASA field experiments across the continental US and Puerto Rico. Where do you see your JOVE research going after the initial JOVE Funding Expires? Our JOVE initiated research will continue to be very active in supporting validation and calibration activities in remote sensing involving NASA, DOE, DOD, NSF, and possibly commercial supported programs. Future effort will focus on projects related to NASA's Mission to Planet Earth. This will include field work using PGAMS and data analysis that evaluates sensor calibration and atmospheric effects in images recorded by ASTER, MODIS, and MISR instruments aboard the AM-1 platform.

Atmospheric correction of HJ-1 CCD imagery over turbid lake waters.

PubMed

Zhang, Minwei; Tang, Junwu; Dong, Qing; Duan, Hongtao; Shen, Qian

2014-04-07

We have presented an atmospheric correction algorithm for HJ-1 CCD imagery over Lakes Taihu and Chaohu with highly turbid waters. The Rayleigh scattering radiance (Lr) is calculated using the hyperspectral Lr with a wavelength interval 1nm. The hyperspectral Lr is interpolated from Lr in the central wavelengths of MODIS bands, which are converted from the band response-averaged Lr calculated using the Rayleigh look up tables (LUTs) in SeaDAS6.1. The scattering radiance due to aerosol (La) is interpolated from La at MODIS band 869nm, which is derived from MODIS imagery using a shortwave infrared atmospheric correction scheme. The accuracy of the atmospheric correction algorithm is firstly evaluated by comparing the CCD measured remote sensing reflectance (Rrs) with MODIS measurements, which are validated by the in situ data. The CCD measured Rrs is further validated by the in situ data for a total of 30 observation stations within ± 1h time window of satellite overpass and field measurements. The validation shows the mean relative errors about 0.341, 0.259, 0.293 and 0.803 at blue, green, red and near infrared bands.

Principle Component Analysis of AIRS and CrIS Data

NASA Technical Reports Server (NTRS)

Aumann, H. H.; Manning, Evan

2015-01-01

Synthetic Eigen Vectors (EV) used for the statistical analysis of the PC reconstruction residual of large ensembles of data are a novel tool for the analysis of data from hyperspectral infrared sounders like the Atmospheric Infrared Sounder (AIRS) on the EOS Aqua and the Cross-track Infrared Sounder (CrIS) on the SUOMI polar orbiting satellites. Unlike empirical EV, which are derived from the observed spectra, the synthetic EV are derived from a large ensemble of spectra which are calculated assuming that, given a state of the atmosphere, the spectra created by the instrument can be accurately calculated. The synthetic EV are then used to reconstruct the observed spectra. The analysis of the differences between the observed spectra and the reconstructed spectra for Simultaneous Nadir Overpasses of tropical oceans reveals unexpected differences at the more than 200 mK level under relatively clear conditions, particularly in the mid-wave water vapor channels of CrIS. The repeatability of these differences using independently trained SEV and results from different years appears to rule out inconsistencies in the radiative transfer algorithm or the data simulation. The reasons for these discrepancies are under evaluation.

Derivation of gravity wave intrinsic parameters and vertical wavelength using a single scanning OH(3-1) airglow spectrometer

NASA Astrophysics Data System (ADS)

Wüst, Sabine; Offenwanger, Thomas; Schmidt, Carsten; Bittner, Michael; Jacobi, Christoph; Stober, Gunter; Yee, Jeng-Hwa; Mlynczak, Martin G.; Russell, James M., III

2018-05-01

For the first time, we present an approach to derive zonal, meridional, and vertical wavelengths as well as periods of gravity waves based on only one OH* spectrometer, addressing one vibrational-rotational transition. Knowledge of these parameters is a precondition for the calculation of further information, such as the wave group velocity vector.OH(3-1) spectrometer measurements allow the analysis of gravity wave ground-based periods but spatial information cannot necessarily be deduced. We use a scanning spectrometer and harmonic analysis to derive horizontal wavelengths at the mesopause altitude above Oberpfaffenhofen (48.09° N, 11.28° E), Germany for 22 nights in 2015. Based on the approximation of the dispersion relation for gravity waves of low and medium frequencies and additional horizontal wind information, we calculate vertical wavelengths. The mesopause wind measurements nearest to Oberpfaffenhofen are conducted at Collm (51.30° N, 13.02° E), Germany, ca. 380 km northeast of Oberpfaffenhofen, by a meteor radar.In order to compare our results, vertical temperature profiles of TIMED-SABER (thermosphere ionosphere mesosphere energetics dynamics, sounding of the atmosphere using broadband emission radiometry) overpasses are analysed with respect to the dominating vertical wavelength.

ECLIPS at LMD: Preliminary results of phase 2

NASA Technical Reports Server (NTRS)

Valentin, R.; Menenger, L.; Elouragini, S.; Flamant, P. H.; Pelon, J.

1992-01-01

The LMD (Laboratoire de Meteorologie Dynamique) ground-based backscatter lidar station (48 degrees 4 N, 02 degrees 0 E) near Paris was operated daily during the phase 2 of the Experimental Closed Lidar Pilot Study (ECLIPS) from May 22 to June 19, 1991 simultaneously with a radiometric equipment recording the downward short wavelength (SW) and long wavelength (LW) fluxes. A day-by-day summary of the field measurement as a function of universal time (UT) is given. Considering a 5 days week, there are only two days of missing data (05/31 and 06/06) in our record. The nearby meteorological station (10 km away) provides rawindsounding at 00UT and 12UT. During two days, the French airborne lidar LEANDRE was flown over the ground-based station. The airborne equipment looked down while the ground based equipment looked up. The two lidars were operated at 532 nm, and the on-board radiometers were identical to the ones on the ground. The measurements were synchronized with Advanced Very High Resolution Radiometer (AVHIRR) overpasses as required. We also indicate the Meteosat data corresponding to the period of measurements. Two examples of simultaneous ground-based lidar, pygeometer and pyranometer data are displayed.

A new high resolution permafrost map of Iceland from Earth Observation data

NASA Astrophysics Data System (ADS)

Barnie, Talfan; Conway, Susan; Balme, Matt; Graham, Alastair

2017-04-01

High resolution maps of permafrost are required for ongoing monitoring of environmental change and the resulting hazards to ecosystems, people and infrastructure. However, permafrost maps are difficult to construct - direct observations require maintaining networks of sensors and boreholes in harsh environments and are thus limited in extent in space and time, and indirect observations require models or assumptions relating the measurements (e.g. weather station air temperature, basal snow temperature) to ground temperature. Operationally produced Land Surface Temperature maps from Earth Observation data can be used to make spatially contiguous estimates of mean annual skin temperature, which has been used a proxy for the presence of permafrost. However these maps are subject to biases due to (i) selective sampling during the day due to limited satellite overpass times, (ii) selective sampling over the year due to seasonally varying cloud cover, (iii) selective sampling of LST only during clearsky conditions, (iv) errors in cloud masking (v) errors in temperature emissivity separation (vi) smoothing over spatial variability. In this study we attempt to compensate for some of these problems using a bayesian modelling approach and high resolution topography-based downscaling.

Utility Rate Equations of Group Population Dynamics in Biological and Social Systems

PubMed Central

Yukalov, Vyacheslav I.; Yukalova, Elizaveta P.; Sornette, Didier

2013-01-01

We present a novel system of equations to describe the evolution of self-organized structured societies (biological or human) composed of several trait groups. The suggested approach is based on the combination of ideas employed in the theory of biological populations, system theory, and utility theory. The evolution equations are defined as utility rate equations, whose parameters are characterized by the utility of each group with respect to the society as a whole and by the mutual utilities of groups with respect to each other. We analyze in detail the cases of two groups (cooperators and defectors) and of three groups (cooperators, defectors, and regulators) and find that, in a self-organized society, neither defectors nor regulators can overpass the maximal fractions of about each. This is in agreement with the data for bee and ant colonies. The classification of societies by their distance from equilibrium is proposed. We apply the formalism to rank the countries according to the introduced metric quantifying their relative stability, which depends on the cost of defectors and regulators as well as their respective population fractions. We find a remarkable concordance with more standard economic ranking based, for instance, on GDP per capita. PMID:24386163

Inversion Schemes to Retrieve Atmospheric and Oceanic Parameters from SeaWiFS Data

NASA Technical Reports Server (NTRS)

Frouin, Robert; Deschamps, Pierre-Yves

1997-01-01

Firstly, we have analyzed atmospheric transmittance and sky radiance data connected at the Scripps Institution of Oceanography pier, La Jolla during the winters of 1993 and 1994. Aerosol optical thickness at 870 nm was generally low in La Jolla, with most values below 0.1 after correction for stratospheric aerosols. For such low optical thickness, variability in aerosol scattering properties cannot be determined, and a mean background model, specified regionally under stable stratospheric component, may be sufficient for ocean color remote sensing, from space. For optical thicknesses above 0. 1, two modes of variability characterized by Angstrom exponents of 1.2 and 0.5 and corresponding, to Tropospheric and Maritime models, respectively, were identified in the measurements. The aerosol models selected for ocean color remote sensing, allowed one to fit, within measurement inaccuracies, the derived values of Angstrom exponent and 'pseudo' phase function (the product of single scattering albedo and phase function), key atmospheric correction parameters. Importantly, the 'pseudo' phase function can be derived from measurements of the Angstrom exponent. Shipborne sun photometer measurements at the time of satellite overpass are usually sufficient to verify atmospheric correction for ocean color.

Utility rate equations of group population dynamics in biological and social systems.

PubMed

Yukalov, Vyacheslav I; Yukalova, Elizaveta P; Sornette, Didier

2013-01-01

We present a novel system of equations to describe the evolution of self-organized structured societies (biological or human) composed of several trait groups. The suggested approach is based on the combination of ideas employed in the theory of biological populations, system theory, and utility theory. The evolution equations are defined as utility rate equations, whose parameters are characterized by the utility of each group with respect to the society as a whole and by the mutual utilities of groups with respect to each other. We analyze in detail the cases of two groups (cooperators and defectors) and of three groups (cooperators, defectors, and regulators) and find that, in a self-organized society, neither defectors nor regulators can overpass the maximal fractions of about [Formula: see text] each. This is in agreement with the data for bee and ant colonies. The classification of societies by their distance from equilibrium is proposed. We apply the formalism to rank the countries according to the introduced metric quantifying their relative stability, which depends on the cost of defectors and regulators as well as their respective population fractions. We find a remarkable concordance with more standard economic ranking based, for instance, on GDP per capita.

Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers

PubMed Central

Rosenfeld, Daniel; Zheng, Youtong; Hashimshoni, Eyal; Pöhlker, Mira L.; Jefferson, Anne; Pöhlker, Christopher; Yu, Xing; Zhu, Yannian; Liu, Guihua; Yue, Zhiguo; Fischman, Baruch; Li, Zhanqing; Giguzin, David; Goren, Tom; Artaxo, Paulo; Pöschl, Ulrich

2016-01-01

Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25° restricts the satellite coverage to ∼25% of the world area in a single day. PMID:26944081

Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers.

PubMed

Rosenfeld, Daniel; Zheng, Youtong; Hashimshoni, Eyal; Pöhlker, Mira L; Jefferson, Anne; Pöhlker, Christopher; Yu, Xing; Zhu, Yannian; Liu, Guihua; Yue, Zhiguo; Fischman, Baruch; Li, Zhanqing; Giguzin, David; Goren, Tom; Artaxo, Paulo; Barbosa, Henrique M J; Pöschl, Ulrich; Andreae, Meinrat O

2016-05-24

Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25° restricts the satellite coverage to ∼25% of the world area in a single day.

Recording ground motions where people live

NASA Astrophysics Data System (ADS)

Cranswick, E.; Gardner, B.; Hammond, S.; Banfill, R.

The 1989 Loma Prieta, Calif., earthquake caused spectacular damage to structures up to 100 km away in the San Francisco Bay sedimentary basin, including the Cypress Street viaduct overpass, the Bay Bridge, and buildings in the San Francisco Marina district. Although the few mainshock ground motions recorded in the northern San Francisco Bay area were “significantly larger … than would be expected from the pre-existing data set,” none were recorded at the sites of these damaged structures [Hanks and Krawinkler, 1991].Loma Prieta aftershocks produced order-of-magnitude variations of ground motions related to sedimentary basin response over distances of 1-2 km and less [Cranswick et al., 1990]. In densely populated neighborhoods, these distances can encompass the residences of thousands of people, but it is very unlikely that these neighborhoods are monitored by even one seismograph. In the last decade, the complexity of computer models used to simulate high-frequency ground motions has increased by several orders of magnitude [e.g., Frankel and Vidale, 1992], but the number of seismograph stations—hence, the spatial density of the sampling of ground motion data—has remained relatively unchanged. Seismologists must therefore infer the nature of the ground motions in the great unknown regions between observation points.

Use of EO-1 Advanced Land Imager (ALI) multispectral image data and real-time field sampling for water quality mapping in the Hirfanlı Dam Lake, Turkey.

PubMed

Kavurmacı, Murat; Ekercin, Semih; Altaş, Levent; Kurmaç, Yakup

2013-08-01

This paper focuses on the evaluation of water quality variations in Hirfanlı Water Reservoir, which is one of the most important water resources in Turkey, through EO-1 (Earth Observing-1) Advanced Land Imager (ALI) multispectral data and real-time field sampling. The study was materialized in 20 different sampling points during the overpass of the EO-1 ALI sensor over the study area. A multi-linear regression technique was used to explore the relationships between radiometrically corrected EO-1 ALI image data and water quality parameters: chlorophyll a, turbidity, and suspended solids. The retrieved and verified results show that the measured and estimated values of water quality parameters are in good agreement (R (2) >0.93). The resulting thematic maps derived from EO-1 multispectral data for chlorophyll a, turbidity, and suspended solids show the spatial distribution of the water quality parameters. The results indicate that the reservoir has average nutrient values. Furthermore, chlorophyll a, turbidity, and suspended solids values increased at the upstream reservoir and shallow coast of the Hirfanlı Water Reservoir.

Great Lakes Hyperspectral Water Quality Instrument Suite for Airborne Monitoring of Algal Blooms

NASA Technical Reports Server (NTRS)

Lekki, John; Leshkevich, George; Nguyen, Quang-Viet; Flatico, Joseph; Prokop, Norman; Kojima, Jun; Anderson, Robert; Demers, James; Krasowski, Michael

2007-01-01

NASA Glenn Research Center and NOAA Great Lakes Environmental Research Lab are collaborating to utilize an airborne hyperspectral imaging sensor suite to monitor Harmful Algal Blooms (HABs) in the western basin of Lake Erie. The HABs are very dynamic events as they form, spread and then disappear within a 4 to 8 week time period in late summer. They are a concern for human health, fish and wildlife because they can contain blue green toxic algae. Because of this toxicity there is a need for the blooms to be continually monitored. This situation is well suited for aircraft based monitoring because the blooms are a very dynamic event and they can spread over a large area. High resolution satellite data is not suitable by itself because it will not give the temporal resolution due to the infrequent overpasses of the quickly changing blooms. A custom designed hyperspectral imager and a point spectrometer mounted on aT 34 aircraft have been used to obtain data on an algal bloom that formed in the western basin of Lake Erie during September 2006. The sensor suite and operations will be described and preliminary hyperspectral data of this event will be presented

Violent Storm Strikes Western Europe

NASA Image and Video Library

2010-03-03

Image acquired February 27, 2010: An extratropical cyclone named Xynthia brought hurricane-force winds and high waves to Western Europe at the end of February 2010, CNN reported. Winds as fast as 200 kilometers (125 miles) per hour reached as far inland as Paris, and at the storm’s peak, hurricane-force winds extended from Portugal to the Netherlands. Hundreds of people had to take refuge from rising waters on their rooftops. By March 1, at least 58 people had died, some of them struck by falling trees. Most of the deaths occurred in France, but the storm also caused casualties in England, Germany, Belgium, Spain, and Portugal. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this image of Western Europe, acquired in two separate overpasses on February 27, 2010. MODIS captured the eastern half of the image around 10:50 UTC, and the western half about 12:30 UTC. Forming a giant comma shape, clouds stretch from the Atlantic Ocean to northern Italy. NASA image courtesy MODIS Rapid Response Team at NASA Goddard Space Flight Center. Caption by Michon Scott. Instrument: Aqua - MODIS For more information related to this image go to: earthobservatory.nasa.gov/NaturalHazards/view.php?id=42881

The Soil Moisture Dependence of TRMM Microwave Imager Rainfall Estimates

NASA Astrophysics Data System (ADS)

Seyyedi, H.; Anagnostou, E. N.

2011-12-01

This study presents an in-depth analysis of the dependence of overland rainfall estimates from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) on the soil moisture conditions at the land surface. TMI retrievals are verified against rainfall fields derived from a high resolution rain-gauge network (MESONET) covering Oklahoma. Soil moisture (SOM) patterns are extracted based on recorded data from 2000-2007 with 30 minutes temporal resolution. The area is divided into wet and dry regions based on normalized SOM (Nsom) values. Statistical comparison between two groups is conducted based on recorded ground station measurements and the corresponding passive microwave retrievals from TMI overpasses at the respective MESONET station location and time. The zero order error statistics show that the Probability of Detection (POD) for the wet regions (higher Nsom values) is higher than the dry regions. The Falls Alarm Ratio (FAR) and volumetric FAR is lower for the wet regions. The volumetric missed rain for the wet region is lower than dry region. Analysis of the MESONET-to-TMI ratio values shows that TMI tends to overestimate for surface rainfall intensities less than 12 (mm/h), however the magnitude of the overestimation over the wet regions is lower than the dry regions.

Polemics on Ethical Aspects in the Compost Business.

PubMed

Maroušek, Josef; Hašková, Simona; Zeman, Robert; Žák, Jaroslav; Vaníčková, Radka; Maroušková, Anna; Váchal, Jan; Myšková, Kateřina

2016-04-01

This paper focuses on compost use in overpasses and underpasses for wild animals over roads and other similar linear structures. In this context, good quality of compost may result in faster and more resistant vegetation cover during the year. Inter alia, this can be interpreted also as reduction of damage and saving lives. There are millions of tones of plant residue produced every day worldwide. These represent prospective business for manufacturers of compost additives called "accelerators". The opinions of the sale representatives' with regards to other alternatives of biowaste utilization and their own products were reviewed. The robust analyzes of several "accelerated" composts revealed that the quality was generally low. Only two accelerated composts were somewhat similar in quality to the blank sample that was produced according to the traditional procedure. Overlaps between the interests of decision makers on future soil fertility were weighed against the preferences on short-term profit. Possible causes that allowed the boom of these underperforming products and the possible consequences are also discussed. Conclusions regarding the ethical concerns on how to run businesses with products whose profitability depends on weaknesses in the legal system and customer unawareness are to follow.

Use of a GCM to Explore Sampling Issues in Connection with Satellite Remote Sensing of the Earth Radiation Budget

NASA Technical Reports Server (NTRS)

Fowler, Laura D.; Wielicki, Bruce A.; Randall, David A.; Branson, Mark D.; Gibson, Gary G.; Denn, Fredrick M.

2000-01-01

Collocated in time and space, top-of-the-atmosphere measurements of the Earth radiation budget (ERB) and cloudiness from passive scanning radiometers, and lidar- and radar-in-space measurements of multilayered cloud systems, are the required combination to improve our understanding of the role of clouds and radiation in climate. Experiments to fly multiple satellites "in formation" to measure simultaneously the radiative and optical properties of overlapping cloud systems are being designed. Because satellites carrying ERB experiments and satellites carrying lidars- or radars-in space have different orbital characteristics, the number of simultaneous measurements of radiation and clouds is reduced relative to the number of measurements made by each satellite independently. Monthly averaged coincident observations of radiation and cloudiness are biased when compared against more frequently sampled observations due, in particular, to the undersampling of their diurnal cycle, Using the Colorado State University General Circulation Model (CSU GCM), the goal of this study is to measure the impact of using simultaneous observations from the Earth Observing System (EOS) platform and companion satellites flying lidars or radars on monthly averaged diagnostics of longwave radiation, cloudiness, and its cloud optical properties. To do so, the hourly varying geographical distributions of coincident locations between the afternoon EOS (EOS-PM) orbit and the orbit of the ICESAT satellite set to fly at the altitude of 600 km, and between the EOS PM orbit and the orbits of the PICASSO satellite proposed to fly at the altitudes of 485 km (PICA485) or 705 km (PICA705), are simulated in the CSU GCM for a 60-month time period starting at the idealistic July 1, 2001, launch date. Monthly averaged diagnostics of the top-of-the-atmosphere, atmospheric, and surface longwave radiation budgets and clouds accumulated over grid boxes corresponding to satellite overpasses are compared against monthly averaged diagnostics obtained from hourly samplings over the entire globe. Results show that differences between irregularly (satellite) and regularly (true) sampled diagnostics of the longwave net radiative budgets are the greatest at the surface and the smallest in the atmosphere and at the top-of-the-atmosphere, under both cloud-free and cloudy conditions. In contrast, differences between the satellite and the true diagnostics of the longwave cloud radiative forcings are the largest in the atmosphere and at the top-of-the-atmosphere, and the smallest at the surface. A poorer diurnal sampling of the surface temperature in the satellite simulations relative to the true simulation contributes a major part to sampling biases in the longwave net radiative budgets, while a poorer diurnal sampling of cloudiness and its optical properties directly affects diagnostics of the longwave cloud radiative forcings. A factor of 8 difference in the number of satellite overpasses between PICA705 and PICA485 and ICESAT leads to a systematic factor of 3 difference in the spatial standard deviations of all radiative and cloudiness diagnostics.

Use of Radar Vegetation Index (RVI) in Passive Microwave Algorithms for Soil Moisture Estimates

NASA Astrophysics Data System (ADS)

Rowlandson, T. L.; Berg, A. A.

2013-12-01

The Soil Moisture Active Passive (SMAP) satellite will provide a unique opportunity for the estimation of soil moisture by having simultaneous radar and radiometer measurements available. As with the Soil Moisture and Ocean Salinity (SMOS) satellite, the soil moisture algorithms will need to account for the contribution of vegetation to the brightness temperature. Global maps of vegetation volumetric water content (VWC) are difficult to obtain, and the SMOS mission has opted to estimate the optical depth of standing vegetation by using a relationship between the VWC and the leaf area index (LAI). LAI is estimated from optical remote sensing or through soil-vegetation-atmosphere transfer modeling. During the growing season, the VWC of agricultural crops can increase rapidly, and if cloud cover exists during an optical acquisition, the estimation of LAI may be delayed, resulting in an underestimation of the VWC and overestimation of the soil moisture. Alternatively, the radar vegetation index (RVI) has shown strong correlation and linear relationship with VWC for rice and soybeans. Using the SMAP radar to produce RVI values that are coincident to brightness temperature measurements may eliminate the need for LAI estimates. The SMAP Validation Experiment 2012 (SMAPVEX12) was a cal/val campaign for the SMAP mission held in Manitoba, Canada, during a 6-week period in June and July, 2012. During this campaign, soil moisture measurements were obtained for 55 fields with varying soil texture and vegetation cover. Vegetation was sampled from each field weekly to determine the VWC. Soil moisture measurements were taken coincident to overpasses by an aircraft carrying the Passive and Active L-band System (PALS) instrumentation. The aircraft flew flight lines at both high and low altitudes. The low altitude flight lines provided a footprint size approximately equivalent to the size of the SMAPVEX12 field sites. Of the 55 field sites, the low altitude flight lines provided measurements for 15 fields. One field was planted in corn; three were pasture; six were soybeans; three were wheat; and two were winter wheat. The average RVI for each field was determined for each PALS overpass, with sampled radar data confined to the field dimensions. A linear interpolation was conducted between measured values of VWC to estimate a daily VWC value. A linear regression was conducted between the average VWC and the RVI, for each vegetation type. A positive linear relationship was found for all crops, with the exception of pasture. The correlation between the RVI and VWC was strong for corn and pasture, but moderate for soybeans and winter wheat; however, the correlation for corn was not significant. The developed models were utilized to provide a calculated VWC which was inputted into a modified version of the Land Parameter Retrieval Model (LPRM) to determine the error associated with using a calculated VWC from the RVI versus measured VWC data. The LPRM outputs for both scenarios were compared to the PALS radiometer measurements of brightness temperature.

A New Model for Solving Time-Cost-Quality Trade-Off Problems in Construction

PubMed Central

Fu, Fang; Zhang, Tao

2016-01-01

A poor quality affects project makespan and its total costs negatively, but it can be recovered by repair works during construction. We construct a new non-linear programming model based on the classic multi-mode resource constrained project scheduling problem considering repair works. In order to obtain satisfactory quality without a high increase of project cost, the objective is to minimize total quality cost which consists of the prevention cost and failure cost according to Quality-Cost Analysis. A binary dependent normal distribution function is adopted to describe the activity quality; Cumulative quality is defined to determine whether to initiate repair works, according to the different relationships among activity qualities, namely, the coordinative and precedence relationship. Furthermore, a shuffled frog-leaping algorithm is developed to solve this discrete trade-off problem based on an adaptive serial schedule generation scheme and adjusted activity list. In the program of the algorithm, the frog-leaping progress combines the crossover operator of genetic algorithm and a permutation-based local search. Finally, an example of a construction project for a framed railway overpass is provided to examine the algorithm performance, and it assist in decision making to search for the appropriate makespan and quality threshold with minimal cost. PMID:27911939

Are motorway wildlife passages worth building? Vertebrate use of road-crossing structures on a Spanish motorway.

PubMed

Mata, C; Hervás, I; Herranz, J; Suárez, F; Malo, J E

2008-08-01

Numerous road and railway construction projects include costly mitigation measures to offset the barrier effect produced on local fauna, despite the scarcity of data on the effectiveness of such mitigation measures. In this study, we evaluate the utility of different types of crossing structures. Vertebrate use of 43 transverse crossing structures along the A-52 motorway (north-western Spain) was studied during spring 2001. Research centered on wildlife passages (9), wildlife-adapted box culverts (7), functional passages (6 overpasses, 7 underpasses) and culverts (14), with marble dust being used to record animal tracks. A total of 424 track-days were recorded, with most of the larger vertebrate groups present in the area being detected. All crossing structure types were used by animals, although the intensity of use varied significantly among them (Kruskal-Wallis test, p<0.05); culverts were used less frequently than other structures. Crossing structure type and width were identified as the most important factors in their selection for use. Wildlife passages and adapted culverts allowed crossing by certain species (wild boar, roe deer, Eurasian badger), which do not tend to cross elsewhere. These results highlight the importance of using both mixed-type structures and wildlife passages in reducing the barrier effect of roads.

An introduction to issues of habitat fragmentation relative to transportation corridors with special reference to high-speed rail (HSR)

NASA Astrophysics Data System (ADS)

de Santo, Robert S.; Smith, Dwight G.

1993-01-01

Potential environmental impacts on wildlife result from siting and construction (short-term impacts) and habitat removal and fragmentation (long-term impacts) as a consequence of transportation corridor construction. Especially in rural districts, wildlife migration corridors and dispersal orientation are altered or destroyed and wildlife populations and their gene pools are isolated. This significantly weakens the wildlife community. Prudent selection of construction corridors reduces fragmentation impacts by maximizing preserved fragment sizes, and by running parallel to, not through, natural areas. Corridor width determines the degree to which wildlife movement is restricted except that culverts, underpasses, overpasses, and one-way gates, can aid wildlife in cross movements. Minimum underpass dimensions for large wildlife should be no smaller than 14 ft×14 ft and should include natural substratum inverts. Rail corridors have four characteristics that minimize adverse environmental impacts. The railbed is dry, ballast fillters runoff, there is little runoff beyond the toe of slope, and drainage ditches serve to control sheet flow and erosion, sediment movement, and uncontrolled channel flow. Rail corridors usually occupy smaller land areas because they are narrower and are more feasible to elevate so as to allow free movement of wildlife across the corridor.

Assessment of the Collection 6 Terra and Aqua MODIS bands 1 and 2 calibration performance

NASA Astrophysics Data System (ADS)

Wu, A.; Chen, X.; Angal, A.; Li, Y.; Xiong, X.

2015-09-01

MODIS (Moderate Resolution Imaging Spectroradiometer) is a key sensor aboard the Terra (EOS AM) and Aqua (EOS PM) satellites. MODIS collects data in 36 spectral bands and generates over 40 data products for land, atmosphere, cryosphere and oceans. MODIS bands 1 and 2 have nadir spatial resolution of 250 m, compared with 500 m for bands 3 to 7 and 1000 m for all the remaining bands, and their measurements are crucial to derive key land surface products. This study evaluates the calibration performance of the Collection-6 L1B for both Terra and Aqua MODIS bands 1 and 2 using three vicarious approaches. The first and second approaches focus on stability assessment using data collected from two pseudo-invariant sites, Libya 4 desert and Antarctic Dome C snow surface. The third approach examines the relative stability between Terra and Aqua in reference to a third sensor from a series of NOAA 15-19 Advanced Very High Resolution Radiometer (AVHRR). The comparison is based on measurements from MODIS and AVHRR Simultaneous Nadir Overpasses (SNO) over a thirteen-year period from 2002 to 2015. Results from this study provide a quantitative assessment of Terra and Aqua MODIS bands 1 and 2 calibration stability and the relative calibration differences between the two sensors.

Microphysical Cloud Regimes used as a tool to study Aerosol-Cloud-Precipitation-Radiation interactions

NASA Astrophysics Data System (ADS)

Cho, N.; Oreopoulos, L.; Lee, D.

2017-12-01

The presentation will examine whether the diagnostic relationships between aerosol and cloud-affected quantities (precipitation, radiation) obtained from sparse temporal resolution measurements from polar orbiting satellites can potentially demonstrate actual aerosol effects on clouds with appropriate analysis. The analysis relies exclusively on Level-3 (gridded) data and comprises systematic cloud classification in terms of "microphysical cloud regimes" (µCRs), aerosol optical depth (AOD) variations relative to a region's local seasonal climatology, and exploitation of the 3-hour difference between Terra (morning) and Aqua (afternoon) overpasses. Specifically, our presentation will assess whether Aerosol-Cloud-Precipitation-Radiation interactions (ACPRI) can be diagnosed by investigating: (a) The variations with AOD of afternoon cloud-affected quantities composited by afternoon or morning µCRs; (b) µCR transition diagrams composited by morning AOD quartiles; (c) whether clouds represented by ensemble cloud effective radius - cloud optical thickness joint histograms look distinct under low and high AOD conditions when preceded or followed by specific µCRs. We will explain how our approach addresses long-standing themes of the ACPRI problem such as the optimal ways to decompose the problem by cloud class, the prevalence and detectability of 1st/2nd aerosol indirect effects and invigoration, and the effectiveness of aerosol changes in inducing cloud modification at different segments of the AOD distribution.

Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosenfeld, Daniel; Zheng, Youtong; Hashimshoni, Eyal

Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities ( Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. In this paper, our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation ( S) is determined by Wb and the satellite-retrieved cloud basemore » drop concentrations ( Ndb), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. Finally, the limitation for small solar backscattering angles of <25° restricts the satellite coverage to ~25% of the world area in a single day.« less

Statistical considerations in creating water vapor data records from combinations of satellite and other observation types, including in situ and ground-based remote sensing

NASA Astrophysics Data System (ADS)

Dykema, J. A.; Anderson, J. G.

2014-12-01

Measuring water vapor at the highest spatial and temporal at all vertical levels and at arbitrary times requires strategic utilization of disparate observations from satellites, ground-based remote sensing, and in situ measurements. These different measurement types have different response times and very different spatial averaging properties, both horizontally and vertically. Accounting for these different measurement properties and explicit propagation of associated uncertainties is necessary to test particular scientific hypotheses, especially in cases of detection of weak signals in the presence of natural fluctuations, and for process studies with small ensembles. This is also true where ancillary data from meteorological analyses are required, which have their own sampling limitations and uncertainties. This study will review two investigations pertaining to measurements of water vapor in the mid-troposphere and lower stratosphere that mix satellite observations with observations from other sources. The focus of the mid-troposphere analysis is to obtain improved estimates of water vapor at the instant of a sounding satellite overpass. The lower stratosphere work examines the uncertainty inherent in a small ensemble of anomalously elevated lower stratospheric water vapor observations when meteorological analysis products and aircraft in situ observations are required for interpretation.

Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers

DOE PAGES

Rosenfeld, Daniel; Zheng, Youtong; Hashimshoni, Eyal; ...

2016-03-04

Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities ( Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. In this paper, our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation ( S) is determined by Wb and the satellite-retrieved cloud basemore » drop concentrations ( Ndb), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. Finally, the limitation for small solar backscattering angles of <25° restricts the satellite coverage to ~25% of the world area in a single day.« less

Estimating seasonal evapotranspiration from temporal satellite images

USGS Publications Warehouse

Singh, Ramesh K.; Liu, Shu-Guang; Tieszen, Larry L.; Suyker, Andrew E.; Verma, Shashi B.

2012-01-01

Estimating seasonal evapotranspiration (ET) has many applications in water resources planning and management, including hydrological and ecological modeling. Availability of satellite remote sensing images is limited due to repeat cycle of satellite or cloud cover. This study was conducted to determine the suitability of different methods namely cubic spline, fixed, and linear for estimating seasonal ET from temporal remotely sensed images. Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC) model in conjunction with the wet METRIC (wMETRIC), a modified version of the METRIC model, was used to estimate ET on the days of satellite overpass using eight Landsat images during the 2001 crop growing season in Midwest USA. The model-estimated daily ET was in good agreement (R2 = 0.91) with the eddy covariance tower-measured daily ET. The standard error of daily ET was 0.6 mm (20%) at three validation sites in Nebraska, USA. There was no statistically significant difference (P > 0.05) among the cubic spline, fixed, and linear methods for computing seasonal (July–December) ET from temporal ET estimates. Overall, the cubic spline resulted in the lowest standard error of 6 mm (1.67%) for seasonal ET. However, further testing of this method for multiple years is necessary to determine its suitability.

Is tretinoin still a key agent for photoaging management?

PubMed

Ascenso, Andreia; Ribeiro, Helena; Marques, Helena C; Oliveira, Helena; Santos, Conceicao; Simões, Sandra

2014-01-01

BACKGROUND & SCOPE OF THE REVIEW: This review focuses on the UV radiation effects on skin, emphasizing the photoaging process, and the photoprotection conferred by tretinoin (all-trans retinoic acid or ATRA). Tretinoin is still the best tested retinoid to reverse photoaged skin. Tretinoin can be used for photoaging treatment or combined treatment by different mechanisms. It binds to and activates retinoic acid receptors, inducing changes in gene expression that leads to cell differentiation, decreased cell proliferation, and inhibition of tumourigenesis. It has been demonstrated that photoaging resulting from UV-B radiation can be treated by retinoid formulations. Pretreatment of human skin with tretinoin blocks dermal matrix degradation followed by sun exposure, inhibiting the induction of the activated protein-1 (AP-1) transcription factor and AP-1 regulated matrix-degrading metalloproteinases. GENERAL SIGNIFICANCE AND INTEREST: Tretinoin should be considered as a key factor as it is the most potent and best-studied retinoid. In addition, the development of advanced drug delivery systems, especially novel nanoformulations, has contributed to overpass some technical drawbacks besides the skin irritation potential. The triple combination of tretinoin, hydroquinone and corticosteroids is still considered the gold standard for melasma. Although there are other novel therapeutic approaches, more high-quality clinical trials are still needed.

Consistency Between Convection Allowing Model Output and Passive Microwave Satellite Observations

NASA Astrophysics Data System (ADS)

Bytheway, J. L.; Kummerow, C. D.

2018-01-01

Observations from the Global Precipitation Measurement (GPM) core satellite were used along with precipitation forecasts from the High Resolution Rapid Refresh (HRRR) model to assess and interpret differences between observed and modeled storms. Using a feature-based approach, precipitating objects were identified in both the National Centers for Environmental Prediction Stage IV multisensor precipitation product and HRRR forecast at lead times of 1, 2, and 3 h at valid times corresponding to GPM overpasses. Precipitating objects were selected for further study if (a) the observed feature occurred entirely within the swath of the GPM Microwave Imager (GMI) and (b) the HRRR model predicted it at all three forecast lead times. Output from the HRRR model was used to simulate microwave brightness temperatures (Tbs), which were compared to those observed by the GMI. Simulated Tbs were found to have biases at both the warm and cold ends of the distribution, corresponding to the stratiform/anvil and convective areas of the storms, respectively. Several experiments altered both the simulation microphysics and hydrometeor classification in order to evaluate potential shortcomings in the model's representation of precipitating clouds. In general, inconsistencies between observed and simulated brightness temperatures were most improved when transferring snow water content to supercooled liquid hydrometeor classes.

Integration of remote sensing technique and hydrologic model for monitoring tidal flat dynamics of Juiduansha in Shanghai

NASA Astrophysics Data System (ADS)

Zheng, Zongsheng; Zhou, Yunxuan; Jiang, Xuezhong

2007-06-01

Ground survey is restricted by the difficulty of access to wide-range and dynamic salt marsh. Waterline method and hydrodynamic model were investigated to construct Digital Elevation Model (DEM) at Jiudunasha Shoals. A series of waterlines were extracted from multi-temporal remotely sensing images collected over the period of 2000-2004. The assignment of an elevation to each waterline at the satellite overpass was performed according to hydrodynamic model. The corrected waterlines labeled elevations were used to construct Triangulated Irregular Networks (TINs). Then an interpolation for each grid elevation was performed in accordance with the associated triangle. This initial DEM, produced using the corrected waterline set, was then used to refine the topography in the intertidal zone, and the model was re-run to produce improved water levels and a new DEM. This procedure was iterated by comparing modeled and actual waterlines until no further improvement occurred. Three DEMs of different intervals were built by this approach and were compared to evaluate the effect of Deep Water Channel Project (DWCP) at the north of Jiuduansha Island. Waterline method combined with numerical model, is an effective tool for constructing digital elevation model of mudflats. The result can provide invaluable information for coastal land use and engineer construction.

A Review of Oil Spill Remote Sensing

PubMed Central

Brown, Carl E.

2017-01-01

The technical aspects of oil spill remote sensing are examined and the practical uses and drawbacks of each technology are given with a focus on unfolding technology. The use of visible techniques is ubiquitous, but limited to certain observational conditions and simple applications. Infrared cameras offer some potential as oil spill sensors but have several limitations. Both techniques, although limited in capability, are widely used because of their increasing economy. The laser fluorosensor uniquely detects oil on substrates that include shoreline, water, soil, plants, ice, and snow. New commercial units have come out in the last few years. Radar detects calm areas on water and thus oil on water, because oil will reduce capillary waves on a water surface given moderate winds. Radar provides a unique option for wide area surveillance, all day or night and rainy/cloudy weather. Satellite-carried radars with their frequent overpass and high spatial resolution make these day–night and all-weather sensors essential for delineating both large spills and monitoring ship and platform oil discharges. Most strategic oil spill mapping is now being carried out using radar. Slick thickness measurements have been sought for many years. The operative technique at this time is the passive microwave. New techniques for calibration and verification have made these instruments more reliable. PMID:29301212

Measurements of Pollution in the Troposphere (MOPITT) Validation Exercises During Summer 2004 Field Campaigns over North America

NASA Technical Reports Server (NTRS)

Emmons, L. K.; Pfister, G. G.; Edwards, D. P.; Gille, J. C.; Sachse, G.; Blake, D.; Wofsy, S.; Gerbig, C.; Matross, D.; Nedelec, P.

2007-01-01

Measurements of carbon monoxide (CO) made as part of three aircraft experiments during the summer of 2004 over North America have been used for the continued validation of the CO retrievals from the Measurements of Pollution in the Troposphere (MOPITT) instrument on board the Terra satellite. Vertical profiles measured during the NASA INTEX-A campaign, designed to be coincident with MOPITT overpasses, as well as measurements made during the COBRA-2004 and MOZAIC experiments, provided valuable validation comparisons. On average, the MOPITT CO retrievals are biased slightly high for these North America locations. While the mean bias differs between the different aircraft experiments (e.g., 7.0 ppbv for MOZAIC to 18.4 ppbv for COBRA at 700 hPa), the standard deviations are quite large, so the results for the three data sets can be considered consistent. On average, it is estimated that MOPITT is 7- 14% high at 700 hPa and 03% high at 350 hPa. These results are consistent with the validation results for the Carr, Colorado, Harvard Forest, Massachusetts, and Poker Flats, Alaska, aircraft profiles for "phase 2" presented by Emmons et al. (2004) and are generally within the design criteria of 10% accuracy.

A comparative study of measurements from radiosondes, rocketsondes, and satellites

NASA Technical Reports Server (NTRS)

Nestler, M. S.

1983-01-01

Direct comparisons of operational products derived from measurements of radiance by satellites to measurements from conventional in situ sensors are important for the evaluation of satellite systems. However, errors in the in situ measurements themselves complicate such comparisons. Atmospheric temporal and spatial variability are also influential. These issues are investigated by means of a special field program composed of flights of dual radiosondes and multiple radiosondes launched near the time of NOAA-6 overpasses. Satellite derived mean layer temperatures, geopotential heights, and winds are compared with the same quantities determined from the in situ sensors. Of particular interest is the impact of in situ errors on these comparisons. It is shown that the radiosonde provides a precise pressure height relationship and therefore precise data for synoptic type use. Radar tracking of the radiosondes reveals, however, an imprecise pressure measurement which causes large differences between the actual altitude of the radiosonde and the altitude at which it is calculated to be. Radiosondes should be radar tracked and pressures calculated if the data are to be used for purposes other than synoptic use. Evaluation of rocketsonde data reveals a temperature precision of 1 to 2 K below about 55 km. Above 55 km, the precision decreases rapidly; rms differences of up to 11 K are obtained.

CrIS High Resolution Hyperspectral Radiances

NASA Astrophysics Data System (ADS)

Hepplewhite, C. L.; Strow, L. L.; Motteler, H.; Desouza-Machado, S. G.; Tobin, D. C.; Martin, G.; Gumley, L.

2014-12-01

The CrIS hyperspectral sounder flying on Suomi-NPPpresently has reduced spectral resolution in the mid-wave andshort-wave spectral bands due to truncation of the interferograms inorbit. CrIS has occasionally downlinked full interferograms for thesebands (0.8 cm max path, or 0.625 cm-1 point spacing) for a feworbits up to a full day. Starting Oct.1, 2014 CrIS will be commandedto download full interferograms continuously for the remainder of themission, although NOAA will not immediately produce high-spectralresolution Sensor Data Records (SDRs). Although the originalmotivation for operating in high-resolution mode was improved spectralcalibration, these new data will also improve (1) vertical sensitivityto water vapor, and (2) greatly increase the CrIS sensitivity tocarbon monoxide. This should improve (1) NWP data assimilation ofwater vapor and (2) provide long-term continuity of carbon monoxideretrievals begun with MOPITT on EOS-TERRA and AIRS on EOS-AQUA. Wehave developed a SDR algorithm to produce calibrated high-spectralresolution radiances which includes several improvements to theexisting CrIS SDR algorithm, and will present validation of thesehigh-spectral resolution radiances using a variety of techniques,including bias evaluation versus NWP model data and inter-comparisonsto AIRS and IASI using simultaneous nadir overpasses (SNOs). Theauthors are presently working to implement this algorithm for NASASuomi NPP Program production of Earth System Data Records.

A New Infrared Desert Dust Index over French Guyana Rain forest: First results

NASA Astrophysics Data System (ADS)

Molinie, J.; Barnacin, E.; Henry, J. L.; Gobinddass, M. L.; Panechou-Pulcherie, K.; Feuillard, T.; Nagau, J.

2017-12-01

Recently a NASA researcher showed the role of desert dust contribution for the Amazonian rain forest. In another hand, desert dust impact population health when PM 10 level reached values around and upper the PM 10 threshold of the 50 µg m-3, established by the World Health Organization (WHO). Infrared Desert Dust Index (IDDI) developed by Legrand with Meteosat infrared images, allow the following of desert dust plumes over semi-arid land. In French Guiana the WHO threshold is currently overpass in measurements done by ORA air quality network, in the two main towns located close to the coast. For inland population, it is very difficult to have continuous dust measures due to the low infrastructure supplies. We need to develop a tools in order to follow the crossing of desert dust over the French Guyana rain forest, from the coast to inland villages. Following the IDDI concept and comparing with VIIRS AOT EDR result over the same area, a modified IDDI for Amazonian region (IDDI_A) has been proposed to identify the dusty pixels over the forest. Despite of high cloud presence, a good correlation between AOT EDR and IDDI_A was obtained. The IDDI_A calculation has been applied over French Guiana area for different PM 10 level at Cayenne, a town along the coast.

In-Situ Transfer Standard and Coincident-View Intercomparisons for Sensor Cross-Calibration

NASA Technical Reports Server (NTRS)

Thome, Kurt; McCorkel, Joel; Czapla-Myers, Jeff

2013-01-01

There exist numerous methods for accomplishing on-orbit calibration. Methods include the reflectance-based approach relying on measurements of surface and atmospheric properties at the time of a sensor overpass as well as invariant scene approaches relying on knowledge of the temporal characteristics of the site. The current work examines typical cross-calibration methods and discusses the expected uncertainties of the methods. Data from the Advanced Land Imager (ALI), Advanced Spaceborne Thermal Emission and Reflection and Radiometer (ASTER), Enhanced Thematic Mapper Plus (ETM+), Moderate Resolution Imaging Spectroradiometer (MODIS), and Thematic Mapper (TM) are used to demonstrate the limits of relative sensor-to-sensor calibration as applied to current sensors while Landsat-5 TM and Landsat-7 ETM+ are used to evaluate the limits of in situ site characterizations for SI-traceable cross calibration. The current work examines the difficulties in trending of results from cross-calibration approaches taking into account sampling issues, site-to-site variability, and accuracy of the method. Special attention is given to the differences caused in the cross-comparison of sensors in radiance space as opposed to reflectance space. The results show that cross calibrations with absolute uncertainties lesser than 1.5 percent (1 sigma) are currently achievable even for sensors without coincident views.

Estimating actual evapotranspiration from remote sensing imagery using R: the package 'TriangleMethod'.

NASA Astrophysics Data System (ADS)

Gampe, David; Huber García, Verena; Marzahn, Philip; Ludwig, Ralf

2017-04-01

Actual evaporation (Eta) is an essential variable to assess water availability, drought risk and food security, among others. Measurements of Eta are however limited to a small footprint, hampering a spatially explicit analysis and application and are very often not available at all. To overcome the problem of data scarcity, Eta can be assessed by various remote sensing approaches such as the Triangle Method (Jiang & Islam, 1999). Here, Eta is estimated by using the Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST). In this study, the R-package 'TriangleMethod' was compiled to efficiently perform the calculations of NDVI and processing LST to finally derive Eta from the applied data set. The package contains all necessary calculation steps and allows easy processing of a large data base of remote sensing images. By default, the parameterization for the Landsat TM and ETM+ sensors are implemented, however, the algorithms can be easily extended to additional sensors. The auxiliary variables required to estimate Eta with this method, such as elevation, solar radiation and air temperature at the overpassing time, can be processed as gridded information to allow for a better representation of the study area. The package was successfully applied in various studies in Spain, Palestine, Costa Rica and Canada.

Validating the AIRS Version 5 CO Retrieval with DACOM In Situ Measurements During INTEX-A and -B

NASA Technical Reports Server (NTRS)

McMillan, Wallace W.; Evans, Keith D.; Barnet, Christopher D.; Maddy, Eric; Sachse, Glen W.; Diskin, Glenn S.

2011-01-01

Herein we provide a description of the atmospheric infrared sounder (AIRS) version 5 (v5) carbon monoxide (CO) retrieval algorithm and its validation with the DACOM in situ measurements during the INTEX-A and -B campaigns. All standard and support products in the AIRS v5 CO retrieval algorithm are documented. Building on prior publications, we describe the convolution of in situ measurements with the AIRS v5 CO averaging kernel and first-guess CO profile as required for proper validation. Validation is accomplished through comparison of AIRS CO retrievals with convolved in situ CO profiles acquired during the NASA Intercontinental Chemical Transport Experiments (INTEX) in 2004 and 2006. From 143 profiles in the northern mid-latitudes during these two experiments, we find AIRS v5 CO retrievals are biased high by 6% 10% between 900 and 300 hPa with a root-mean-square error of 8% 12%. No significant differences were found between validation using spiral profiles coincident with AIRS overpasses and in-transit profiles under the satellite track but up to 13 h off in time. Similarly, no significant differences in validation results were found for ocean versus land, day versus night, or with respect to retrieved cloud top pressure or cloud fraction.

Soil, water, and vegetation conditions in south Texas. [Hildago County, Texas

NASA Technical Reports Server (NTRS)

Wiegand, C. L.; Gausman, H. W.; Leamer, R. W.; Richardson, A. J. (Principal Investigator)

1975-01-01

The author has identified the following significant results. To distinguish dead from live vegetation, spectrophotometrically measured infinite reflectance of dead and live corn (Zea mays L.) leaves were compared over the 0.5 to 2.5 micron waveband. Dead leaf reflectance was reached over the entire 0.5 to 2.5 micron waveband by stacking only two to three leaves. Live leaf reflectance was attained by stacking two leaves for the 0.5 to 0.75 micron waveband (chlorophyll absorption region), eight leaves for the 0.75 to 1.35 micron waveband (near infrared region), and three leaves for the 1.35 to 2.5 micron waveband (water absorption region). LANDSAT-1 MSS digital data for 11 December 1973 overpass were used to estimate the sugar cane acreage in Hidalgo County. The computer aided estimate was 22,100 acres compared with the Texas Crop and Livestock Reporting Service estimate of 20,500 acres for the 1973-'74 crop year. Although there were errors of omission from harvested fields that were identified as bare soil and some citrus and native vegetation that were mistakenly identified as sugar cane, the mapped location of sugar cane fields in the county compared favorably with their location on the thematic map generated by the computer.

Landsat 4 Thematic Mapper calibration update

USGS Publications Warehouse

Helder, Dennis L.; Malla, Rimy; Mettler, Cory J.; Markham, Brian L.; Micijevic, Esad

2012-01-01

The Landsat 4 Thematic Mapper (TM) collected imagery of the Earth's surface from 1982 to 1993. Although largely overshadowed by Landsat 5 which was launched in 1984, Landsat 4 TM imagery extends the TM-based record of the Earth back to 1982 and also substantially supplements the image archive collected by Landsat 5. To provide a consistent calibration record for the TM instruments, Landsat 4 TM was cross-calibrated to Landsat 5 using nearly simultaneous overpass imagery of pseudo-invariant calibration sites (PICS) in the time period of 1988-1990. To determine if the radiometric gain of Landsat 4 had changed over its lifetime, time series from two PICS locations (a Saharan site known as Libya 4 and a site in southwest North America, commonly referred to as the Sonoran Desert site) were developed. The results indicated that Landsat 4 had been very stable over its lifetime, with no discernible degradation in sensor performance in all reflective bands except band 1. In contrast, band 1 exhibited a 12% decay in responsivity over the lifetime of the instrument. Results from this paper have been implemented at USGS EROS, which enables users of Landsat TM data sets to obtain consistently calibrated data from Landsat 4 and 5 TM as well as Landsat 7 ETM+ instruments.

Inter-Comparison of S-NPP VIIRS and Aqua MODIS Thermal Emissive Bands Using Hyperspectral Infrared Sounder Measurements as a Transfer Reference

NASA Technical Reports Server (NTRS)

Li, Yonghong; Wu, Aisheng; Xiong, Xiaoxiong

2016-01-01

This paper compares the calibration consistency of the spectrally-matched thermal emissive bands (TEB) between the Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) and the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS), using observations from their simultaneous nadir overpasses (SNO). Nearly-simultaneous hyperspectral measurements from the Aqua Atmospheric Infrared Sounder(AIRS) and the S-NPP Cross-track Infrared Sounder (CrIS) are used to account for existing spectral response differences between MODIS and VIIRS TEB. The comparison uses VIIRS Sensor Data Records (SDR) in MODIS five-minute granule format provided by the NASA Land Product and Evaluation and Test Element (PEATE) and Aqua MODIS Collection 6 Level 1 B (L1B) products. Each AIRS footprint of 13.5 km (or CrIS field of view of 14 km) is co-located with multiple MODIS (or VIIRS) pixels. The corresponding AIRS- and CrIS-simulated MODIS and VIIRS radiances are derived by convolutions based on sensor-dependent relative spectral response (RSR) functions. The VIIRS and MODIS TEB calibration consistency is evaluated and the two sensors agreed within 0.2 K in brightness temperature.Additional factors affecting the comparison such as geolocation and atmospheric water vapor content are also discussed in this paper.

Unexpected East-West effect in mesopause region SABER temperatures over El Leoncito

NASA Astrophysics Data System (ADS)

Reisin, Esteban R.; Scheer, Jürgen

2017-05-01

We find that mesopause region temperatures determined by the SABER instrument on the TIMED satellite during nocturnal overpasses at El Leoncito (31.8°S, 69.3°W) are several kelvins higher when SABER observes from the East than when it observes from the West. We distinguish between altitudes corresponding to the nominal emission heights of the OH and O2 airglow layers. The East-West temperature differences of 4.5 K obtained for OH-equivalent height, and of 3.5 K for O2-equivalent height are surprising, because an effect of the South Atlantic Anomaly on SABER temperature is unexpected. However, the ground-based data obtained with our airglow spectrometer at El Leoncito show that such a SABER artifact can be ruled out. Rather, the phenomenon is explained as a consequence of the temporal sampling of the nocturnal variation, which is mostly due to the semidiurnal tide. The monthly mean tide is strongest from April to September with a mean amplitude of 6.9 K for OH, and of 10.5 K for O2 rotational temperature, but the contribution to the East-West effect varies strongly from month to month because of differences in the temporal sampling. This mechanism should be active at other sites, as well.

Characterization of NPP Visible/Infrared Imager Radiometer Suite (VIIRS) Reflective Solar Bands Dual Gain Anomaly

NASA Technical Reports Server (NTRS)

Lee, Shihyan; McIntire, Jeff; Oudari, Hassan

2012-01-01

The Visible/Infrared Imager Radiometer Suite (VIIRS) contains six dual gain bands in the reflective solar spectrum. The dual gain bands are designed to switch gain mode at pre-defined thresholds to achieve high resolution at low radiances while maintaining the required dynamic range for science. During pre-launch testing, an anomaly in the electronic response before transitioning from high to low gain was discovered and characterized. On-orbit, the anomaly was confirmed using MODIS data collected during Simultaneous Nadir Overpasses (SNOs). The analysis of the Earth scene data shows that dual gain anomaly can be determined at the orbital basis. To characterize the dual gain anomaly, the anomaly region and electronic offsets were tracked per week during the first 8 month of VIIRS operation. The temporal analysis shows the anomaly region can drift 20 DN and is impacted by detectors DC Restore. The estimated anomaly flagging regions cover 2.5 % of the high gain dynamic range and are consistent with prelaunch and on-orbit LUT. The prelaunch results had a smaller anomaly range (30-50 DN) and are likely the results of more stable electronics from the shorter data collection time. Finally, this study suggests future calibration efforts to focus on the anomaly's impact on science products and possible correction method to reduce uncertainties.

Millimeter wave scattering characteristics and radar cross section measurements of common roadway objects

NASA Astrophysics Data System (ADS)

Zoratti, Paul K.; Gilbert, R. Kent; Majewski, Ronald; Ference, Jack

1995-12-01

Development of automotive collision warning systems has progressed rapidly over the past several years. A key enabling technology for these systems is millimeter-wave radar. This paper addresses a very critical millimeter-wave radar sensing issue for automotive radar, namely the scattering characteristics of common roadway objects such as vehicles, roadsigns, and bridge overpass structures. The data presented in this paper were collected on ERIM's Fine Resolution Radar Imaging Rotary Platform Facility and processed with ERIM's image processing tools. The value of this approach is that it provides system developers with a 2D radar image from which information about individual point scatterers `within a single target' can be extracted. This information on scattering characteristics will be utilized to refine threat assessment processing algorithms and automotive radar hardware configurations. (1) By evaluating the scattering characteristics identified in the radar image, radar signatures as a function of aspect angle for common roadway objects can be established. These signatures will aid in the refinement of threat assessment processing algorithms. (2) Utilizing ERIM's image manipulation tools, total RCS and RCS as a function of range and azimuth can be extracted from the radar image data. This RCS information will be essential in defining the operational envelope (e.g. dynamic range) within which any radar sensor hardware must be designed.

Surface radiant flux densities inferred from LAC and GAC AVHRR data

NASA Astrophysics Data System (ADS)

Berger, F.; Klaes, D.

To infer surface radiant flux densities from current (NOAA-AVHRR, ERS-1/2 ATSR) and future meteorological (Envisat AATSR, MSG, METOP) satellite data, the complex, modular analysis scheme SESAT (Strahlungs- und Energieflüsse aus Satellitendaten) could be developed (Berger, 2001). This scheme allows the determination of cloud types, optical and microphysical cloud properties as well as surface and TOA radiant flux densities. After testing of SESAT in Central Europe and the Baltic Sea catchment (more than 400scenes U including a detailed validation with various surface measurements) it could be applied to a large number of NOAA-16 AVHRR overpasses covering the globe.For the analysis, two different spatial resolutions U local area coverage (LAC) andwere considered. Therefore, all inferred results, like global area coverage (GAC) U cloud cover, cloud properties and radiant properties, could be intercompared. Specific emphasis could be made to the surface radiant flux densities (all radiative balance compoments), where results for different regions, like Southern America, Southern Africa, Northern America, Europe, and Indonesia, will be presented. Applying SESAT, energy flux densities, like latent and sensible heat flux densities could also be determined additionally. A statistical analysis of all results including a detailed discussion for the two spatial resolutions will close this study.

A Review of Oil Spill Remote Sensing.

PubMed

Fingas, Merv; Brown, Carl E

2017-12-30

The technical aspects of oil spill remote sensing are examined and the practical uses and drawbacks of each technology are given with a focus on unfolding technology. The use of visible techniques is ubiquitous, but limited to certain observational conditions and simple applications. Infrared cameras offer some potential as oil spill sensors but have several limitations. Both techniques, although limited in capability, are widely used because of their increasing economy. The laser fluorosensor uniquely detects oil on substrates that include shoreline, water, soil, plants, ice, and snow. New commercial units have come out in the last few years. Radar detects calm areas on water and thus oil on water, because oil will reduce capillary waves on a water surface given moderate winds. Radar provides a unique option for wide area surveillance, all day or night and rainy/cloudy weather. Satellite-carried radars with their frequent overpass and high spatial resolution make these day-night and all-weather sensors essential for delineating both large spills and monitoring ship and platform oil discharges. Most strategic oil spill mapping is now being carried out using radar. Slick thickness measurements have been sought for many years. The operative technique at this time is the passive microwave. New techniques for calibration and verification have made these instruments more reliable.

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.

Exploring Measures to Control Road Traffic Injuries in Iran: Key Informants Points of View.

PubMed

Salari, Hedayat; Motevalian, Seyed Abbas; Arab, Mohammad; Esfandiari, Atefeh; Akbari Sari, Ali

2017-05-01

Injuries and fatalities from road traffic Injuries are global public health concerns, and a major problem in the Iran. This study aimed to explore strategies to control road traffic Injuries (RTI) in Iran. We conducted a qualitative study to explore possible ways to reduce the occurrence of road traffic Injuries in Iran in 2016. Interviewees were purposively sampled from various sectors due to multidisciplinary nature of RTIs. Participants were mainly representatives from the police, Ministry of Road, Municipal, emergency services and Ministry of Health. Besides, public health authorities, researchers, and university professors were interviewed. We conducted in-depth interviews using generic guides. Data was analyzed using MAXQDA 10 software. Through content analysis, we interpreted core themes relevant to the accomplishment of our study objectives. Themes that emerged from our study include; road traffic management, governance, education, improving accident database, enforcement, driving license restrictions, and construction of pedestrian overpass. This study revealed key informants' views regarding available and affordable solutions to reduce RTIs in Iran. Many applicable strategies are identified in the control of RTIs in Iran. Although some solutions such as highway construction and/or expanding rail transportation have been suggested as effective measures for reducing accident, but they are costly and may not be fully applied in developing countries like Iran.

Bringing HIV, Substance Abuse and Homelessness into the University of Pennsylvania Anthropology Museum through Photo-Ethnography

PubMed Central

Bourgois, Philippe

2013-01-01

In the fall of 1994 I befriended a community of some two dozen heroin injectors and crack smokers surviving under the overpasses of a tangle of freeways six blocks from where I lived in San Francisco. The full force of the Reagan-era cutbacks from the 1980s had trickled down to the street, shredding the already rachitic U.S. welfare safety-net. Inner-cities were gentrifying (especially those linked to the epicenters of global finance capital such as San Francisco). The former skid row habitat for the unstable urban poor—cheap single-residency hotels—was being converted into multi-million dollar condominiums. Urban police forces had not yet systematized, routinized and replicated their zero-tolerance enforcement, harassment/incarceration dragnets (Wacquant 2009) and homelessness, consequently, was at its most visible. Bourgeois residents like me could not walk down a block or drive up a freeway entrance ramp in downtown San Francisco without being solicited for spare change. I obtained a National Institutes of Health HIV prevention grant and for the next 12 years, together with a photographer/anthropologist collaborator Jeff Schonberg and several additional ethnographic team members, we followed the social network of homeless addicts surviving in my neighborhood, documenting the unhealthy effects of indigence and substance abuse. PMID:23885347

Generalized Stone-Wales transformation as the possible origin of ferromagnetism in polymeric C60: a density-functional theory study.

PubMed

Ribas-Ariño, J; Novoa, Juan J

2006-11-07

Recently, there has been a proposal [Y.-H. Kim et al., Phys. Rev. B 68, 125420 (2003)] suggesting that ferromagnetic interactions in compressed and heated polymeric-C(60) solids could be due to the existence of triplet open cages resulting from successive generalized Stone-Wales transformations within the C(60) cage. Here, by performing B3LYP3-21G and B3LYP6-31G(d) optimizations, we carried out a systematic investigation of the thermodynamics and kinetics of the mechanism of generation of these open cages in their closed-shell singlet, open-shell singlet, and triplet states. We also computed the magnetic interactions induced by the open cages presenting a triplet ground state. Our results indicate that this mechanism is not appropriate to explain the ferromagnetism found in compressed and heated polymeric C(60) for the following reasons: (a) the formation of the only open cage presenting a triplet ground state requires overpassing a highest energy point of 318 kcal/mol, well above other competitive mechanisms reported in the literature; the triplet open cages formed are not stable against their transformation into a diamagnetic intermediate; (c) the magnetic interactions between two adjacent triplet open cages are antiferromagnetic.

Low-Temperature Wet Conformal Nickel Silicide Deposition for Transistor Technology through an Organometallic Approach.

PubMed

Lin, Tsung-Han; Margossian, Tigran; De Marchi, Michele; Thammasack, Maxime; Zemlyanov, Dmitry; Kumar, Sudhir; Jagielski, Jakub; Zheng, Li-Qing; Shih, Chih-Jen; Zenobi, Renato; De Micheli, Giovanni; Baudouin, David; Gaillardon, Pierre-Emmanuel; Copéret, Christophe

2017-02-08

The race for performance of integrated circuits is nowadays facing a downscale limitation. To overpass this nanoscale limit, modern transistors with complex geometries have flourished, allowing higher performance and energy efficiency. Accompanying this breakthrough, challenges toward high-performance devices have emerged on each significant step, such as the inhomogeneous coverage issue and thermal-induced short circuit issue of metal silicide formation. In this respect, we developed a two-step organometallic approach for nickel silicide formation under near-ambient temperature. Transmission electron and atomic force microscopy show the formation of a homogeneous and conformal layer of NiSi x on pristine silicon surface. Post-treatment decreases the carbon content to a level similar to what is found for the original wafer (∼6%). X-ray photoelectron spectroscopy also reveals an increasing ratio of Si content in the layer after annealing, which is shown to be NiSi 2 according to X-ray absorption spectroscopy investigation on a Si nanoparticle model. I-V characteristic fitting reveals that this NiSi 2 layer exhibits a competitive Schottky barrier height of 0.41 eV and series resistance of 8.5 Ω, thus opening an alternative low-temperature route for metal silicide formation on advanced devices.

A Comparison of TOMS Version 8 Total Column Ozone Data with Data from Groundstations

NASA Technical Reports Server (NTRS)

Labow, G. J.; McPeters, R. D.; Bhartia, P. K.

2004-01-01

The Nimbus-7 and Earth Probe Total Ozone Mapping Spectrometer (TOMS) data have been reprocessed with a new retrieval algorithm, (Version 8) and an updated calibration procedure. These data have been systematically compared to total ozone data from Brewer and Dobson spectrophotometers for 73 individual ground stations. The comparisons were made as a function of latitude, solar zenith angle, reflectivity and total ozone. Results show that the accuracy of the TOMS retrieval'is much improved when aerosols are present in the atmosphere, when snow/ice and sea glint are present, and when ozone in the northern hemisphere is extremely low. TOMS overpass data are derived from the single TOMS best match measurement, almost always located within one degree of the ground station and usually made within an hour of local noon. The version 8 Earth Probe TOMS ozone values have decreased by an average of about 1% due to a much better understanding of the calibration of the instrument. The remaining differences between TOMS and ground stations suggest that there are still small errors in the TOMS retrievals. But if TOMS is used as a transfer standard to compare ground stations, the large station-to-station differences suggest the possibility of significant instrument errors at some ground stations.

Observing relationships between lightning and cloud profiles by means of a satellite-borne cloud radar

NASA Astrophysics Data System (ADS)

Buiat, Martina; Porcù, Federico; Dietrich, Stefano

2017-01-01

Cloud electrification and related lightning activity in thunderstorms have their origin in the charge separation and resulting distribution of charged iced particles within the cloud. So far, the ice distribution within convective clouds has been investigated mainly by means of ground-based meteorological radars. In this paper we show how the products from Cloud Profiling Radar (CPR) on board CloudSat, a polar satellite of NASA's Earth System Science Pathfinder (ESSP), can be used to obtain information from space on the vertical distribution of ice particles and ice content and relate them to the lightning activity. The analysis has been carried out, focusing on 12 convective events over Italy that crossed CloudSat overpasses during significant lightning activity. The CPR products considered here are the vertical profiles of cloud ice water content (IWC) and the effective radius (ER) of ice particles, which are compared with the number of strokes as measured by a ground lightning network (LINET). Results show a strong correlation between the number of strokes and the vertical distribution of ice particles as depicted by the 94 GHz CPR products: in particular, cloud upper and middle levels, high IWC content and relatively high ER seem to be favourable contributory causes for CG (cloud to ground) stroke occurrence.

Vertical Structure and Sources of Aerosols in the Mediterranean Region (VESSAER)

NASA Astrophysics Data System (ADS)

Roberts, G. C.; Junkermann, W.; Leon, J.; Pont, V.; Mallet, M.; Augustin, P.; Dulac, F.

2012-12-01

The Mediterranean region has been identified as one of the most prominent global "Hot-Spots" in future climate change projections [Giorgi and Lionello, 2008] and is particularly characterized by its vulnerability to changes in the water cycle. To this end, the VESSAER campaign (VErtical Structure and Sources of AERosols in the Mediterranean Region) was designed to characterize the different sources of aerosol in the Mediterranean Basin and assess their regional impact on cloud microphysical and radiative properties. VESSAER was conducted on the ENDURO-KIT ultra-light aircraft [W. Junkermann, 2001] in late June-early July 2012. Activities include ground observations as well as aerosol lidar and sunphotometer measurements in conjunction with the airborne measurements. The VESSAER campaign complements existing ChArMEx (http://charmex.lsce.ipsl.fr/ ; PI: F. Dulac) and HyMeX (http://www.hymex.org/ ; PI: V. Ducroc and P. Drobinski) activities, which are the target of many European research institutes in 2012 and 2013. The main scientific goals during VESSAER are to investigate local versus long-range sources of aerosol and cloud condensation nuclei (CCN) and their vertical stratification in the lower troposphere, use aerosol hygroscopicity to study their evolution due to atmospheric processes, and couple in-situ airborne measurements with ground-based remote sensing to determine aerosol direct radiative impacts over a larger spatial scale. The background aerosol concentrations within the boundary layer (BL) in Corsica are nearly 2000 cm-3 (Dp > 10 nm); 50 cm-3 (Dp > 300 nm). We were surprised to find that nearly all of these particles are CCN-active at 0.3% supersaturation and presume that ageing and/or cloud processing play a role in rendering the aerosol in the Mediterranean Basin more hygroscopic. The vertical profiles during VESSAER clearly show the long-range transport of dust from the Saharan Desert and pollution from the European continent -- which were the two major sources of aerosol during the campaign. Two of the research flights coincided with CALIPSO overpasses. During both dust events, Saharan Dust layers are transported within the lower 5 km. Concentrations of large particles (Dp > 0.3 um) show a corresponding increase throughout the troposphere, and aerosol optical depth increased up to 0.7 (at 440 nm). Comparisons of the overpass with the in-situ measurements and ground-based lidar will be presented. In addition, layers of pollution above the BL show higher number concentrations (up to 6000 cm-3) and lower hygroscopicity than in the BL. These results suggest that downward mixing of European continental pollution contribute to the elevated background aerosol concentrations found throughout the Mediterranean Basin. Giorgi, F. and Lionello, P. (2008). Climate change projections for the Mediterranean region. Global and Planetary Change 63: 90-104. Junkermann, W. (2001). An ultralight aircraft as platform for research in the lower troposphere: System performance and first results from radiation transfer studies in stratiform aerosol layers and broken cloud conditions. Journal of Atmospheric and Oceanic Technology 18: 934 - 946. ---------------- This work was supported by the European Facility for Airborne Research (EUFAR), Météo-France, CEA, ADEME, COST Action ES0802 (Unmanned Aerial Systems in Atmospheric Research).

Google Earth as a Vehicle to Integrating Multiple Layers of Environmental Satellite Data for Weather and Science Applications

NASA Astrophysics Data System (ADS)

Turk, F. J.; Miller, S. D.

2007-12-01

One of the main challenges facing current and future environmental satellite systems (e.g, the future National Polar Orbiting Environmental Satellite System (NPOESS)) is reaching and entraining the diverse user community via communication of how these systems address their particular needs. A necessary element to meeting this challenge is effective data visualization: facilitating the display, animation and layering of multiple satellite imaging and sounding sensors (providing complementary information) in a user-friendly and intuitive fashion. In light of the fact that these data are rapidly making their way into the classroom owing to efficient and timely data archival systems and dissemination over the Internet, there is a golden opportunity to leverage existing technology to introduce environmental science to wide spectrum of users. Google Earth's simplified interface and underlying markup language enables access to detailed global geographic information, and contains features which are both desirable and advantageous for geo-referencing and combining a wide range of environmental satellite data types. Since these satellite data are available with a variety of horizontal spatial resolutions (tens of km down to hundreds of meters), the imagery can be sub-setted (tiled) at a very small size. This allows low-bandwidth users to efficiently view and animate a sequence of imagery while zoomed out from the surface, whereas high-bandwidth users can efficiently zoom into the finest image resolution when viewing fine-scale phenomena such as fires, volcanic activity, as well as the details of meteorological phenomena such as hurricanes, rainfall, lightning, winds, etc. Dynamically updated network links allow for near real-time updates such that these data can be integrated with other Earth-hosted applications and exploited not only in the teaching environment, but also for operational users in the government and private industry sectors. To conceptualize how environmental satellite data would be utilized within a geobrowser in a near real-time setting, we present a demonstration from the 2007 hurricane season, developed within the Google Earth framework. A menu of imagery based sequential satellite overpasses (GOES and other geostationary satellites, TRMM, CloudSat, Terra, Aqua, DMSP, NOAA, QuikScat) during the storm lifecycle, are presented to the Earth client in an structured folder format. The remapping of these satellite data follows the hurricane track, enabling the user to view, animate, zoom, overlay and combine visible, infrared and passive microwave imagery and combine with other data (surface reports, forecasts, surface winds, ground and spaceborne radars, etc.) at various stages of the hurricane lifecycle. Pop-up balloons provide training that explains the properties and capabilities of the satellite datasets and what components of the underlying weather are represented. Future satellite overpass tracks are provided so that the user can anticipate imagery updates several days in advance (e.g., as a hurricane approaches landfall). This combination of geo-navigable data provides a convenient framework for efficiently demonstrating meteorological, oceanographic and weather and climate concepts to students, planners, and the public at large.

Intercomparison of four airborne imaging DOAS systems for tropospheric NO2 mapping - First results of the AROMAPEX campaign

NASA Astrophysics Data System (ADS)

Tack, Frederik; Merlaud, Alexis; Meier, Andreas; Ge, Xinrui; Meuleman, Koen; Ruhtz, Thomas; van der Wal, Len; Van Roozendael, Michel; Iordache, Daniel; Schönhardt, Anja; Richter, Andreas; Vlemmix, Tim; de Goeij, Bryan; Ardelean, Magdalena; Boscornea, Andreea; Constantin, Daniel; Shaifangar, Reza; Wagner, Thomas; Lampel, Johannes; Schuettemeyer, Dirk

2017-04-01

The AROMAPEX campaign took place in Berlin in April, 2016, co-funded by the EU (EUFAR) and ESA, with the primary objective to intercompare experimental airborne atmospheric imagers dedicated to the mapping of the spatial distribution of tropospheric nitrogen dioxide (NO2). AROMAPEX is also a preparatory step for forthcoming intercomparison/validation campaigns of satellite air quality sensors, such as TROPOMI (TROPOspheric Monitoring Instrument). The instruments were operated from two planes, performing synchronized flights: APEX (VITO/BIRA-IASB) was operated from DLR's DO-228 D-CFFU plane at 6.1 km altitude while AirMAP (IUP Bremen), and the small, lightweight SWING (BIRA-IASB) and Spectrolite (TNO/TU Delft) instruments were operated from the FUB Cessna 207T D-EAFU at 3 km. Two synchronized flights took place on 21 April, 2016, the only cloud-free day during the campaign, in the morning from 09:34 to 12:01 LT and in the afternoon from 14:24 to 16:39 LT. APEX, AirMAP and SWING have a comparable swath width of 3 km, while Spectrolite has a swath of 450 m due to the fact that the field-of-view had to be reduced from 40° to 8.3° for practical reasons. The spatial resolution is approximately 100 m after spatial aggregation for APEX, AirMAP and Spectrolite (pushbroom scanning), and 300 m for SWING (whiskbroom scanning). The airborne Sunphotometer FUBISS-ASA2 was installed and operated during the ascent and descent of the FUB aircraft to derive aerosol optical depth (AOD). During the overpass of the imagers, simultaneous car mobile-DOAS observations were performed with three systems covering transects from north to south and west to east. The ground-based instrumental set-up was completed by a DOAS instrument, an Aeronet station and a ceilometer installed at the rooftop of FUB, located in the southwest of Berlin. The AROMAPEX experiment builds on the experience gained during the AROMAT campaigns held in September, 2014 and August, 2015 in Romania, and the BUMBA campaigns held in April, 2015 and July, 2016 in Belgium. We present first results of an intercomparison study of both the NO2 slant column densities (SCDs) and vertical column densities (VCDs) retrieved from the APEX, AirMAP, SWING and Spectrolite instruments. Two large NO2 plumes, crossing the city from west to east, were detected by all imaging systems with high consistency. Retrieved NO2 VCDs range between 1.5 x 1015 and 2.4 x 1016 molec cm-2. For the sake of harmonizing the different data sets, efforts are currently ongoing to agree on a common set of parameter settings, gridding algorithm and AMF LUT in the NO2 retrieval approach. Despite these efforts, discrepancies will remain due to a combination of (1) instrumental differences, e.g. SNR, spatial and spectral resolution; (2) algorithmic differences, e.g. DOAS fitting, RTM, a priori input; and (3) observation differences, e.g. flight altitude, overpass time and viewing geometry.

Challenging the cervix: strategies to overcome the anatomic impediments to hysteroscopy: analysis of 31,052 office hysteroscopies.

PubMed

Bettocchi, Stefano; Bramante, Silvia; Bifulco, Giuseppe; Spinelli, Marialuigia; Ceci, Oronzo; Fascilla, Fabiana Divina; Di Spiezio Sardo, Attilio

2016-05-01

To report our experience on 10,156 cases of cervical stenosis (CS) diagnosed at office hysteroscopy. Retrospective study. Ambulatory clinics of diagnostic and operative hysteroscopy of two university teaching hospitals (Naples and Bari). A total of 31,052 patients undergoing office hysteroscopy. All of the paper and electronic reports of the office hysteroscopies performed from January 1996 to September 2014 were reviewed. Hysteroscopies were classified as successful (i.e., when access to and visualization of the entire uterine cavity was possible during the same procedure), incomplete (i.e., when access to uterine cavity was possible, but the entire uterine cavity could not be examined), or failed (i.e., when access to uterine cavity was not possible). CS was classified on the basis of localization: stenosis of external cervical ostium (ECO; type I); stenosis of distal third of cervical channel and the internal cervical ostium (ICO; type II); stenosis of the ICO (type III), and combined stenosis of ECO and ICO (type IV). The success rate at overpassing CS (including both successful and incomplete hysteroscopies) was the primary outcome measure. Secondary outcome measures were frequency and localization of CS in fertile and postmenopausal women and the frequency of use of technical maneuvers and/or miniaturized mechanical or bipolar instruments to overcome them. All hysteroscopies were performed with the use of a 5- or 4-mm rigid continuous-flow office operative hysteroscope by operators with different levels of expertise. The hysteroscopy technique used was standardized between the two centers and among all of the surgeons throughout the years. An access to the uterine cavity with a complete evaluation of the whole endometrial surface was possible in 93.9% of cases (29,152 patients). The main reasons of the 1,320 (4.3%) incomplete and 580 (1.9%) failed hysteroscopies were pain and CS, respectively. CS was identified in 10,156 women (32.7% of all procedures) and was significantly more frequent in postmenopausal than in fertile women (70.1% vs. 29.9%), except for type I stenosis, which was more frequent in fertile than in postmenopausal women. Type IV CS (44.3%) was the most commonly detected. Overall, CS was managed successfully with minimal discomfort in 98.5% of cases with technical maneuvers and miniaturized mechanical and/or bipolar instruments. Adhesiolysis with the distal tip of the hysteroscope by rotating the scope on the endocamera was the significantly more used strategy to overpass all types of CS (39.8% of cases), generally used in combination with miniaturized operative instruments (79.2%). Bipolar electrodes were more used in cases of type I and type IV stenosis (39.7%) compared with the other types of CS. CS and pain represent the main reasons for failed hysteroscopy. Recent technical and technologic innovations, together with increased operator experience and optimal pain management, have made it possible to overcome even severe CS with the use of office hysterosocpy, thus significantly reducing the rate of failed procedures and the need for operating room and general anesthesia. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Exploring Measures to Control Road Traffic Injuries in Iran: Key Informants Points of View

PubMed Central

SALARI, Hedayat; MOTEVALIAN, Seyed Abbas; ARAB, Mohammad; ESFANDIARI, Atefeh; AKBARI SARI, Ali

2017-01-01

Background: Injuries and fatalities from road traffic Injuries are global public health concerns, and a major problem in the Iran. This study aimed to explore strategies to control road traffic Injuries (RTI) in Iran. Methods: We conducted a qualitative study to explore possible ways to reduce the occurrence of road traffic Injuries in Iran in 2016. Interviewees were purposively sampled from various sectors due to multidisciplinary nature of RTIs. Participants were mainly representatives from the police, Ministry of Road, Municipal, emergency services and Ministry of Health. Besides, public health authorities, researchers, and university professors were interviewed. We conducted in-depth interviews using generic guides. Data was analyzed using MAXQDA 10 software. Through content analysis, we interpreted core themes relevant to the accomplishment of our study objectives. Results: Themes that emerged from our study include; road traffic management, governance, education, improving accident database, enforcement, driving license restrictions, and construction of pedestrian overpass. Conclusion: This study revealed key informants’ views regarding available and affordable solutions to reduce RTIs in Iran. Many applicable strategies are identified in the control of RTIs in Iran. Although some solutions such as highway construction and/or expanding rail transportation have been suggested as effective measures for reducing accident, but they are costly and may not be fully applied in developing countries like Iran. PMID:28560198

ARM Radiosondes for National Polar-Orbiting Operational Environmental Satellite System Preparatory Project Validation Field Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borg, Lori; Tobin, David; Reale, Anthony

This IOP has been a coordinated effort involving the U.S. Department of Energy (DOE) Atmospheric Radiation (ARM) Climate Research Facility, the University of Wisconsin (UW)-Madison, and the JPSS project to validate SNPP NOAA Unique Combined Atmospheric Processing System (NUCAPS) temperature and moisture sounding products from the Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS). In this arrangement, funding for radiosondes was provided by the JPSS project to ARM. These radiosondes were launched coincident with the SNPP satellite overpasses (OP) at four of the ARM field sites beginning in July 2012 and running through September 2017. Combined withmore » other ARM data, an assessment of the radiosonde data quality was performed and post-processing corrections applied producing an ARM site Best Estimate (BE) product. The SNPP targeted radiosondes were integrated into the NOAA Products Validation System (NPROVS+) system, which collocated the radiosondes with satellite products (NOAA, National Aeronautics and Space Administration [NASA], European Organisation for the Exploitation of Meteorological Satellites [EUMETSAT], Geostationary Operational Environmental Satellite [GOES], Constellation Observing System for Meteorology, Ionosphere, and Climate [COSMIC]) and Numerical Weather Prediction (NWP forecasts for use in product assessment and algorithm development. This work was a fundamental, integral, and cost-effective part of the SNPP validation effort and provided critical accuracy assessments of the SNPP temperature and water vapor soundings.« less

Cross comparison of the Collection 6 and Collection 6.1 Terra and Aqua MODIS Bands 1 and 2 using AVHRR N15 and N19

NASA Astrophysics Data System (ADS)

Chen, Xuexia; Wu, Aisheng; Xiong, Xiaoxiong J.; Chen, Na

2017-09-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) is a key scientific instrument that was launched into Earth orbit by NASA in 1999 on board the Terra (EOS AM) satellite and in 2002 on board the Aqua (EOS PM) satellite. Terra and Aqua MODIS collect the entire Earth's images every 1 to 2 days in 36 spectral bands. MODIS band 1 (0.620- 0.670 μm) and band 2 (0.841-0.876 μm) have nadir spatial resolution of 250 m and their measurements are crucial to derive key land surface products. This study evaluates the performance of the Collection 6 (C6, and C6.1) L1B of both Terra and Aqua MODIS bands 1 and 2 using Simultaneous Nadir Overpass (SNO) data to compare with AVHRR/3 sensors. We examine the relative stability between Terra and Aqua MODIS in reference to NOAA N15 and N19 the Advanced Very High Resolution Radiometer (AVHRR/3). The comparisons for MODIS to AVHRR/3 are over a fifteenyear period from 2002 to 2017. Results from this study provide a quantitative assessment of Terra and Aqua MODIS band 1 and band 2 calibration stability and the relative differences through the NOAA N15 and N19 AVHRR/3 sensors.

University of Washington Airborne Studies in Support of the CLAMS-2001 Field Study

NASA Technical Reports Server (NTRS)

Hobbs, Peter V.

2003-01-01

The main activity under this grant was participation in the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field study from 10 July through 2 August 2001. The Cloud and Aerosol Research Group (CARG) from the University of Washington (UW) flew its Convair-580 research aircraft on thirteen occasions, for a total of 45 research flight hours, in support of CLAMS. Some of the main accomplishments of these flights were: 1) Aerosol and trace gas measurements and sunphotometer measurements of aerosol optical depth and column water vapor and ozone from close to Ocean surface to approx. 10,000 ft off Delmarva Peninsula on various occasions; 2) Measurements of aerosol properties on seven occasions beneath the Terra satellite, once beneath AVHRR, and five times beneath the ER-2 aircraft; 3) Measurements of aerosol properties in the vicinity of the (CERES instrumented) Chesapeake Bay lighthouse (COVE) on nine occasions; 4) Use of the NASA Goddard Cloud Absorption Radiometer (CAR) to obtain measurements of BRDF of the ocean surface on fifteen occasions and over Great Dismal Swamp on two occasions; 5) Measurements of aerosol properties over instrumented buoys 44014, 44004, and 41001. 6) On July 17 (a CLAMS 'Golden Day') six aircraft, including the Convair-580 and ER-2, were stacked above the Chesapeake Bay lighthouse under clear skies at the time of the Terra overpass.

Proposed Trace Gas Measurements Over the Western United States for TROPOMI Validation

NASA Technical Reports Server (NTRS)

Parworth, Caroline L.; Marrero, Josette E.; Yates, Emma L.; Ryoo, Ju-Mee; Iraci, Laura T.

2018-01-01

The Alpha Jet Atmospheric eXperiment (AJAX), located in the Bay Area of California, is a joint effort between NASA Ames Research Center and H211, LCC. AJAX makes in-situ airborne measurements of trace gases 2-4 times per month, resulting in over 216 flights since 2011. Current measurements include ozone (O3), carbon dioxide (CO2), methane (CH4), water (H2O), formaldehyde (HCHO), and meteorological measurements (i.e., ambient pressure, temperature, and 3D winds). Currently, the AJAX team is working to incorporate nitrogen dioxide (NO2) measurements with a Cavity Attenuated Phase Shift Spectrometer (CAPS). Successful science flights coincident with satellite overpasses have been performed since 2011 by the Alpha Jet, with more than 40 flights under the Greenhouse Observing SATellite (GOSAT) and several flights under the Orbiting Carbon Observatory-2 (OCO-2). Results from these flights, which have covered a range of different surfaces and seasonal conditions, will be presented. In-situ vertical profiles of O3, CO2, CH4, H2O, HCHO, and NO2 from the surface to 28,000 feet made by AJAX will also be valuable for satellite validation of data products obtained from the TROPOspheric Montoring Instrument (TROPOMI). TROPOMI is on board the Copernicus Sentinel-5 precursor (S5p) satellite, with level 2 products including O3, CO, CH4, HCHO, NO2, and aerosols.

Radiative Transfer and Satellite Remote Sensing of Cirrus Clouds Using FIRE-2-IFO Data

NASA Technical Reports Server (NTRS)

2000-01-01

Under the support of the NASA grant, we have developed a new geometric-optics model (GOM2) for the calculation of the single-scattering and polarization properties for arbitrarily oriented hexagonal ice crystals. From comparisons with the results computed by the finite difference time domain (FDTD) method, we show that the novel geometric-optics can be applied to the computation of the extinction cross section and single-scattering albedo for ice crystals with size parameters along the minimum dimension as small as approximately 6. We demonstrate that the present model converges to the conventional ray tracing method for large size parameters and produces single-scattering results close to those computed by the FDTD method for size parameters along the minimum dimension smaller than approximately 20. We demonstrate that neither the conventional geometric optics method nor the Lorenz-Mie theory can be used to approximate the scattering, absorption, and polarization features for hexagonal ice crystals with size parameters from approximately 5 to 20. On the satellite remote sensing algorithm development and validation, we have developed a numerical scheme to identify multilayer cirrus cloud systems using AVHRR data. We have applied this scheme to the satellite data collected over the FIRE-2-IFO area during nine overpasses within seven observation dates. Determination of the threshold values used in the detection scheme are based on statistical analyses of these satellite data.

Inflight calibration of the modular airborne imaging spectrometer (MAIS) and its application to reflectance retrieval

NASA Astrophysics Data System (ADS)

Min, Xiangjun; Zhu, Yonghao

1998-08-01

Inflight experiment of Modular Airborne Imaging Spectrometer (MAIS) and ground-based measurements using GER MARK-V spectroradiometer simultaneously with the MAIS overpass were performed during Autumn 1995 at the semiarid area of Inner Mongolia, China. Based on these measurements and MAIS image data, we designed a method for the radiometric calibration of MAIS sensor using 6S and LOWTRAN 7 codes. The results show that the uncertainty of MAIS calibration is about 8% in the visible and near infrared wavelengths (0.4 - 1.2 micrometer). To verify our calibration algorithm, the calibrated results of MAIS sensor was used to derive the ground reflectances. The accuracy of reflectance retrieval is about 8.5% in the spectral range of 0.4 to 1.2 micrometer, i.e., the uncertainty of derived near-nadir reflectances is within 0.01 - 0.05 in reflectance unit at ground reflectance between 3% and 50%. The distinguishing feature of the ground-based measurements, which will be paid special attention in this paper, is that obtaining simultaneously the reflectance factors of the calibration target, atmospheric optical depth, and water vapor abundance from the same one set of measurement data by only one suit of instruments. The analysis indicates that the method presented here is suitable to the quantitative analysis of imaging spectral data in China.

Curiosity's Autonomous Surface Safing Behavior Design

NASA Technical Reports Server (NTRS)

Neilson, Tracy A.; Manning, Robert M.

2013-01-01

The safing routines on all robotic deep-space vehicles are designed to put the vehicle in a power and thermally safe configuration, enabling communication with the mission operators on Earth. Achieving this goal is made a little more difficult on Curiosity because the power requirements for the core avionics and the telecommunication equipment exceed the capability of the single power source, the Multi-Mission Radioisotope Thermoelectric Generator. This drove the system design to create an operational mode, called "sleep mode", where the vehicle turns off most of the loads in order to charge the two Li-ion batteries. The system must keep the vehicle safe from over-heat and under-heat conditions, battery cell failures, under-voltage conditions, and clock failures, both while the computer is running and while the system is sleeping. The other goal of a safing routine is to communicate. On most spacecraft, this simply involves turning on the receiver and transmitter continuously. For Curiosity, Earth is above the horizon only a part of the day for direct communication to the Earth, and the orbiter overpass opportunities only occur a few times a day. The design must robustly place the Rover in a communicable condition at the correct time. This paper discusses Curiosity's autonomous safing behavior and describes how the vehicle remains power and thermally safe while sleeping, as well as a description of how the Rover communicates with the orbiters and Earth at specific times.

Comparison of ozone retrievals from the Pandora spectrometer system and Dobson spectrophotometer in Boulder, Colorado

NASA Astrophysics Data System (ADS)

Herman, J.; Evans, R.; Cede, A.; Abuhassan, N.; Petropavlovskikh, I.; McConville, G.

2015-03-01

A comparison of retrieved total column ozone amounts TCO between the Pandora #34 spectrometer system and the Dobson #061 spectrophotometer from direct-sun observations was performed on the roof of the Boulder, Colorado NOAA building. This paper, part of an ongoing study, covers a one-year period starting on 17 December 2013. Both the standard Dobson and Pandora total column ozone TCO retrievals required a correction TCOcorr = TCO (1+C(T)) using the effective climatology derived ozone temperature T to remove a seasonal difference caused by using a fixed temperature in each retrieval algorithm. The respective corrections C(T) are CPandora = 0.00333(T-225) and CDobson = -0.0013 (T-226.7) per K. After the applied corrections removed the seasonal retrieval dependence on ozone temperature, TCO agreement between the instruments was within 1% for clear-sky conditions. For clear-sky observations, both co-located instruments tracked the day-to-day variation in total column ozone amounts with a correlation of r2 = 0.97 and an average offset of 1.1 ± 5.8 DU. In addition, the Pandora data showed 0.3% annual average agreement with satellite overpass data from AURA/OMI (Ozone Monitoring Instrument) and 1% annual average offset with Suomi-NPP/OMPS (Suomi National Polar-orbiting Partnership, the nadir viewing portion of the Ozone Mapper Profiler Suite).

The Intercalibration of Geostationary Visible Imagers Using Operational Hyperspectral SCIAMACHY Radiances

NASA Technical Reports Server (NTRS)

Doelling, David R.; Scarino, Benjamin R.; Morstad, Daniel; Gopalan, Arun; Bhatt, Rajendra; Lukashin, Constantine; Minnis, Patrick

2013-01-01

Spectral band differences between sensors can complicate the process of intercalibration of a visible sensor against a reference sensor. This can be best addressed by using a hyperspectral reference sensor whenever possible because they can be used to accurately mitigate the band differences. This paper demonstrates the feasibility of using operational Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) large-footprint hyperspectral radiances to calibrate geostationary Earth-observing (GEO) sensors. Near simultaneous nadir overpass measurements were used to compare the temporal calibration of SCIAMACHY with Aqua Moderate Resolution Imaging Spectroradiometer band radiances, which were found to be consistent to within 0.44% over seven years. An operational SCIAMACHY/GEO ray-matching technique was presented, along with enhancements to improve radiance pair sampling. These enhancements did not bias the underlying intercalibration and provided enough sampling to allow up to monthly monitoring of the GEO sensor degradation. The results of the SCIAMACHY/GEO intercalibration were compared with other operational four-year Meteosat-9 0.65-µm calibration coefficients and were found to be within 1% of the gain, and more importantly, it had one of the lowest temporal standard errors of all the methods. This is more than likely that the GEO spectral response function could be directly applied to the SCIAMACHY radiances, whereas the other operational methods inferred a spectral correction factor. This method allows the validation of the spectral corrections required by other methods.

Quantification of Surface Suspended Sediments along a River Dominated Coast with NOAA AVHRR and SeaWiFS Measurements: Louisiana, USA

NASA Technical Reports Server (NTRS)

Myint, S. W.; Walker, N. D.

2002-01-01

The ability to quantify suspended sediment concentrations accurately over both time and space using satellite data has been a goal of many environmental researchers over the past few decades This study utilizes data acquired by the NOAA Advanced Very High Resolution Radiometer (AVHRR) and the Orbview-2 Sea-viewing wide field-of-view (SeaWiFS) ocean colour sensor, coupled with field measurements to develop statistical models for the estimation of near-surface suspended sediment and suspended solids "Ground truth" water samples were obtained via helicopter, small boat and automatic water sampler within a few hours of satellite overpasses The NOAA AVHRR atmospheric correction was modified for the high levels of turbidity along the Louisiana coast. Models were developed based on the field measurements and reflectance/radiance measurements in the visible and near infrared Channels of NOAA-14 and Orbview-2 SeaWiFS. The best models for predicting surface suspended sediment concentrations were obtained with a NOAA AVHRR Channel 1 (580-680nm) cubic model, Channel 2 (725-1100 nm) linear mod$ and SeaWiFs Channel 6 (660-68Onm) power modeL The suspended sediment models developed using SeaWiFS Channel 5 (545-565 nm) were inferior, a result that we attribute mainly to the atmospheric correction technique, the shallow depth of the water samples and absorption effects from non-sediment water constituents.

Results from the 1995 Stratospheric Ozone Profile Intercomparison at Mauna Loa (MLO3)

NASA Technical Reports Server (NTRS)

McPeters, R. D.; Hofmann, D. J.; Clark, M.; Flynn, L.; Froidevaux, L.; Gross, M.; Johnson, B.; Koenig, G.; Liu, X.; McDermid, S.;

Calibration/validation of Landsat-Derived Ocean Colour Products in Boston Harbour

NASA Astrophysics Data System (ADS)

Pahlevan, Nima; Sheldon, Patrick; Peri, Francesco; Wei, Jianwei; Shang, Zhehai; Sun, Qingsong; Chen, Robert F.; Lee, Zhongping; Schaaf, Crystal B.; Schott, John R.; Loveland, Thomas

2016-06-01

The Landsat data archive provides a unique opportunity to investigate the long-term evolution of coastal ecosystems at fine spatial scales that cannot be resolved by ocean colour (OC) satellite sensors. Recognizing Landsat's limitations in applications over coastal waters, we have launched a series of field campaigns in Boston Harbor and Massachusetts Bay (MA, USA) to validate OC products derived from Landsat-8. We will provide a preliminary demonstration on the calibration/validation of the existing OC algorithms (atmospheric correction and in-water optical properties) to enhance monitoring efforts in Boston Harbor. To do so, Landsat optical images were first compared against ocean colour products over high-latitude regions. The in situ cruise data, including optical data (remote sensing reflectance) and water samples were analyzed to obtain insights into the optical and biogeochemical properties of near-surface waters. Along with the cruise data, three buoys were deployed in three locations across the Harbor to complement our database of concentrations of chlorophyll a, total suspended solids (TSS), and absorption of colour dissolved organic matter (CDOM). The data collected during the first year of the project are used to develop and/or tune OC algorithms. The data will be combined with historic field data to map in-water constituents back to the early 1990's. This paper presents preliminary analysis of some of the data collected under Landsat-8 overpasses.

An atlas of upper tropospheric radiances observed in the 6 to 7-micrometer water vapor band using TOVS data from the NOAA weather satellites during 1979-1991

NASA Technical Reports Server (NTRS)

Chesters, Dennis; Sharma, OM

1992-01-01

This document is a pictorial atlas of the Earth's radiance emitted in the 6 to 7 micro-m water vapor band. At these wavelengths, the infrared brightness temperature corresponds to the layer-average temperature of the top few millimeters of water vapor in the atmosphere. At low altitudes, bright regions are dry slots in the upper troposphere. The satellite observations were obtained from NOAA's cloud and angle corrected measurements made by a series of polar orbiting TOVS (TIROS Operational Vertical Sounder) instruments flown from 1979 to 1991. TOVS 6.7 micro-m and 7.2 micro-m channels were converted to a single brightness temperature that simulates a high altitude channel near '6.5' micro-m. For climatological studies, the daily '6.5' micro-m overpass data were gridded to a cartesian projection with 5 by 5 degree horizontal resolution between 40 degrees N and 40 degrees S latitude. This atlas presents greyscale images of the '6.5' micro-m brightness fields for every day in every month for 13 years. The mean brightness for each of the 12 months for 13 years is presented to display interannual variability, and the annual cycle of 12 monthly means is summarized on a single page. Statistical summaries are presented from other investigations in progress.

CERES Fast Longwave And SHortwave Radiative Flux (FLASHFlux) Version4A.

NASA Astrophysics Data System (ADS)

Sawaengphokhai, P.; Stackhouse, P. W., Jr.; Kratz, D. P.; Gupta, S. K.

2017-12-01

The agricultural, renewable energy management, and science communities need global surface and top-of-atmosphere (TOA) radiative fluxes on a low latency basis. The Clouds and Earth's Radiant Energy System (CERES) FLASHFlux (Fast Longwave and SHortwave radiative Flux) data products address this need by enhancing the speed of CERES processing using simplified calibration and parameterized model of surface fluxes to provide a daily global radiative fluxes data set within one week of satellite observations. The CERES FLASHFlux provides two data products: 1) an overpass swath Level 2 Single Scanner Footprint (SSF) data products separately for both Aqua and Terra observations, and 2) a daily Level 3 Time Interpolated and Spatially Averaged (TISA) 1o x 1o gridded data that combines Aqua and Terra observations. The CERES FLASHFlux data product is being promoted to Version4A. Updates to FLASHFlux Version4A include a new cloud retrieval algorithm and an improved shortwave surface flux parameterization. We inter-compared FLASHFlux Version4A, FLASHFlux Version3C, CERES Edition 4 Syn1Deg and at the monthly scale CERES Edition4 EBAF (Energy Balanced and Filled) Top-of-Atmosphere and Edition 4 Surface EBAF fluxes to evaluate these improvements. We also analyze the impact of the new inputs and cloud algorithm to the surface shortwave and longwave radiative fluxes using ground sites measurement provided by CAVE (CERES/ARM Validation Experiment).

A Combined Infrared and Microwave Technique for Studying the Diurnal Variation of Rainfall over Amazonia

NASA Technical Reports Server (NTRS)

Negri, Andrew J.; Anagnostou, Emmanouil; Adler, Robert F.

1999-01-01

Over 10 years of continuous data from the Special Sensor microwave Imager (SSM/I) aboard a series of Defense Department satellites has made it possible to construct regional rainfall climatologies at high spatial resolution. Using the Goddard Profiling Algorithm (GPROF), monthly estimates of precipitation were made over the region of northern Brazil, including the Amazon Basin, for 1987 to 1998. GPROF is a physical approach to passive microwave precipitation retrieval, which uses the Goddard Cumulus Ensemble (cloud) model to establish prior probability densities of precipitation structures. Precipitation fields from GPROF were stratified into morning and evening satellite overpasses, and accumulated at monthly intervals at 0.5 degree spatial resolution. Important diurnal effects were noted in the analysis, the most pronounced being a land/sea breeze circulation along the northern coast of Brazil and a mountain/valley circulation along the Andes. There were also indications of morning rainfall maxima along the major rivers, and evening maxima between the rivers. The addition of simultaneous geosynchronous infrared (IR) data leads to the current technique, which takes advantage of the 30 minute sampling and 4 km spatial resolution of the infrared channel and the better physics of the microwave retrieval. The resultant IR method is subsequently used to derive the diurnal variability of rainfall over the Amazon basin, and further, to investigate the relative contribution from its convective and stratiform components.

A First: NASA Spots Single Methane Leak from Space

NASA Image and Video Library

2016-06-14

Atmospheric methane is a potent greenhouse gas, but the percentage of it produced through human activities is still poorly understood. Future instruments on orbiting satellites can help address this issue by surveying human-produced methane emissions. Recent data from the Aliso Canyon event, a large accidental methane release near Porter Ranch, California, demonstrates this capability. The Hyperion imaging spectrometer onboard NASA's EO-1 satellite successfully detected this release event on three different overpasses during the winter of 2015-2016. This is the first time the methane plume from a single facility has been observed from space. The orbital observations were consistent with airborne measurements. This image pair shows a comparison of detected methane plumes over Aliso Canyon, California, acquired 11 days apart in Jan. 2016 by: (left) NASA's AVIRIS instrument on a NASA ER-2 aircraft at 4.1 miles (6.6 kilometers) altitude and (right) by the Hyperion instrument on NASA's Earth Observing-1 satellite in low-Earth orbit. The additional red streaks visible in the EO-1 Hyperion image result from measurement noise -- Hyperion was not specifically designed for methane sensing and is not as sensitive as AVIRIS-NG. Additionally, the EO-1 satellite's current orbit provided poor illumination conditions. Future instruments with much greater sensitivity on orbiting satellites can survey the biggest sources of human-produced methane around the world. http://photojournal.jpl.nasa.gov/catalog/PIA20716

Intercomparison of Total Atmospheric Precipitable Water Vapor Retrieval Products during the 2009 and 2010 CAPABLE Summer Intensives

NASA Astrophysics Data System (ADS)

Pippin, M. R.; Knepp, T. N.; Bedka, S.; Cowen, L.; Murray, J.; Deslover, D.; Feltz, W.; Yesalusky, M. A.; Smith, W.; Cede, A.; Abuhassan, N.; Herman, J. R.; Szykamn, J.

2011-12-01

In support of NASA's GEO-CAPE mission and Air Quality Applied Sciences, the Chemistry and Physics Atmospheric Boundary Layer Experiment (CAPABLE) site at NASA Langley Research Center has been established in coordination with Environmental Protection Agency (EPA) and Virginia Department of Environmental Quality (VA DEQ) to assess the relationship between high temporal resolution measurements from space and continuous in situ surface observations. During the 2009 and 2010 CAPABLE summer intensives, three methods for determining total atmospheric precipitable water vapor were utilized. Continuous total column measurements of water vapor were provided using a Pandora spectrometer, the DOE/NSTec Atmospheric Sounder Spectrometer for Infrared Spectral Technology (ASSIST) operated by the Hampton University and the University of Wisconsin Atmospheric Emitted Radiance Interferometer (AERI). Continuous meteorological parameters were measured on a 5m tower and rawinsondes were launched intermittently throughout both measurement periods. We present preliminary results of the intercomparison of total precipitable water vapor from the three instrumental methods and compare with estimated values from dew point temperature and satellite overpass data. Results from this study will have applications to satellite validation and Pandora retrieval algorithm development. Disclaimer: Although this work was reviewed by the U.S. Environmental Protection Agency and National Aeronautics and Space Administration, and approved for publication, it may not necessarily reflect official Agency policy.

Global multi-sensor satellite monitoring of volcanic SO2 and ash emissions in support to aviation control

NASA Astrophysics Data System (ADS)

Brenot, H.; Theys, N.; van Gent, J.; Van Roozendael, M.; van der A, R.; Clarisse, L.; Hurtmans, D.; Ngadi, Y.; Coheur, P.-F.; Clerbaux, C.

2012-04-01

The "Support to Aviation Control Service" (SACS; http://sacs.aeronomie.be) is an ESA-funded project hosted by the Belgian Institute for Space Aeronomy. The service provides near real-time (NRT) global SO2 and volcanic ash data, as well as alerts in case of volcanic eruptions. The SACS service is primarily designed to support the Volcanic Ash Advisory Centers (VAACs) in their mandate to gather information on volcanic clouds and give advice to airline and air traffic control organisations. SACS also serves other users that subscribe to the service, in particular local volcano observatories and research scientists. SACS is based on the combined use of UV-visible (SCIAMACHY, OMI, GOME-2) and infrared (AIRS, IASI) satellite instruments. When a volcanic eruption is detected, SACS issues an alert that takes the form of a notification sent by e-mail to users. This notification points to a dedicated web page where all relevant information is available and can be visualized with user-friendly tools. The strength of a multi-sensor approach relies in the use of satellite data with different overpasses times, minimizing the time-lag for detection and enhancing the reliability of such alerts. This paper will give a general presentation of the SACS service, different techniques used to detect volcanic plumes. It will also highlight the strengths and limitations of the service and measurements.

The application of large numbers of pleasure boats to collect synoptic sea-truth for ERTS-1 overpasses

NASA Technical Reports Server (NTRS)

Klemas, V. (Principal Investigator); Davis, G.; Philpot, W.

1974-01-01

The author has identified the following significant results. In order to interpret and annotate current circulation and suspended sediment concentration maps derived from ERTS-1 digital tapes, the University of Delaware has been collecting water samples and other data from boats and helicopters. In order to increase the number of samples at the exact time of the ERTS-1 pass over Delaware Bay, pleasure craft were organized to obtain samples of the entire test site. On the ERTS-1 pass of July second, scientists were stationed at three public boat launches along the Bay to hand out sampling packets to interested boaters. The packets contained two litre sampling bottles, a map, data card, and a pen. The boaters were asked to fill the two bottles between 11 and 11:15 a.m., mark their location on the map, and fill out the data card. Forty-nine packets were handed out of which 40 were returned (82%). Only four of the 40 were not in the alloted time range. This gave 36 real time data points covering approximately 30 nautical miles. The samples are being analyzed for sediment concentration, particle size, and salinity. Participating boaters will receive a copy of an ERTS image of the Delaware Bay and a summary report of the project. Because of the success of the project, future use of pleasure boaters is being planned.

Comparison of TOMS, SBW & SBUV/2 Version 8 Total Column Ozone Data with Data from Groundstations

NASA Technical Reports Server (NTRS)

Labow, G. J.; McPeters, R. D.; Bhartia, P. K.

2004-01-01

The Nimbus-7 and Earth Probe Total Ozone Mapping Spectrometer (TOMS) data as well as SBUV and SBUV/2 data have been reprocessed with a new retrieval algorithm (Version 8) and an updated calibration procedure. An overview will be presented systematically comparing ozone values to an ensemble of Brewer and Dobson spectrophotometers. The comparisons were made as a function of latitude, solar zenith angle, reflectivity and total ozone. Results show that the accuracy of the TOMS retrieval has been improved when aerosols are present in the atmosphere, when snow/ice and sea glint are present, and when ozone in the northern hemisphere is extremely low. TOMS overpass data are derived from the single TOMS best match measurement, almost always located within one degree of the ground station and usually made within an hour of local noon. The Version 8 Earth Probe TOMS ozone values have decreased by an average of about 1% due to a much better understanding of the calibration of the instrument. N-7 SBUV as well as the series of NOAA SBUV/2 column ozone values have also been processed with the Version 8 algorithm and have been compared to values from an ensemble of groundstations. Results show that the SBW column ozone values agree well with the groundstations and the datasets are useful for trend studies.

An Advanced Bio-Inspired PhotoPlethysmoGraphy (PPG) and ECG Pattern Recognition System for Medical Assessment

PubMed Central

Rundo, Francesco; Ortis, Alessandro

2018-01-01

Physiological signals are widely used to perform medical assessment for monitoring an extensive range of pathologies, usually related to cardio-vascular diseases. Among these, both PhotoPlethysmoGraphy (PPG) and Electrocardiography (ECG) signals are those more employed. PPG signals are an emerging non-invasive measurement technique used to study blood volume pulsations through the detection and analysis of the back-scattered optical radiation coming from the skin. ECG is the process of recording the electrical activity of the heart over a period of time using electrodes placed on the skin. In the present paper we propose a physiological ECG/PPG “combo” pipeline using an innovative bio-inspired nonlinear system based on a reaction-diffusion mathematical model, implemented by means of the Cellular Neural Network (CNN) methodology, to filter PPG signal by assigning a recognition score to the waveforms in the time series. The resulting “clean” PPG signal exempts from distortion and artifacts is used to validate for diagnostic purpose an EGC signal simultaneously detected for a same patient. The multisite combo PPG-ECG system proposed in this work overpasses the limitations of the state of the art in this field providing a reliable system for assessing the above-mentioned physiological parameters and their monitoring over time for robust medical assessment. The proposed system has been validated and the results confirmed the robustness of the proposed approach. PMID:29385774

An Advanced Bio-Inspired PhotoPlethysmoGraphy (PPG) and ECG Pattern Recognition System for Medical Assessment.

PubMed

Rundo, Francesco; Conoci, Sabrina; Ortis, Alessandro; Battiato, Sebastiano

2018-01-30

Physiological signals are widely used to perform medical assessment for monitoring an extensive range of pathologies, usually related to cardio-vascular diseases. Among these, both PhotoPlethysmoGraphy (PPG) and Electrocardiography (ECG) signals are those more employed. PPG signals are an emerging non-invasive measurement technique used to study blood volume pulsations through the detection and analysis of the back-scattered optical radiation coming from the skin. ECG is the process of recording the electrical activity of the heart over a period of time using electrodes placed on the skin. In the present paper we propose a physiological ECG/PPG "combo" pipeline using an innovative bio-inspired nonlinear system based on a reaction-diffusion mathematical model, implemented by means of the Cellular Neural Network (CNN) methodology, to filter PPG signal by assigning a recognition score to the waveforms in the time series. The resulting "clean" PPG signal exempts from distortion and artifacts is used to validate for diagnostic purpose an EGC signal simultaneously detected for a same patient. The multisite combo PPG-ECG system proposed in this work overpasses the limitations of the state of the art in this field providing a reliable system for assessing the above-mentioned physiological parameters and their monitoring over time for robust medical assessment. The proposed system has been validated and the results confirmed the robustness of the proposed approach.

In-Situ Detection of SO2 Plumes in Costa Rica from Turrialba Volcano using Balloon-borne Sondes

NASA Astrophysics Data System (ADS)

Diaz, J. A.; Selkirk, H. B.; Morris, G. A.; Krotkov, N. A.; Pieri, D. C.; Corrales, E.

2012-12-01

The Turrialba Volcano near San Jose, Costa Rica regularly emits plumes containing SO2. These plumes have been detected by the Ozone Monitoring Instrument (OMI), and evidence of these plumes has also appeared in the in-situ Ticosonde project record: a continuous balloon-borne ozonesonde launch experiment conducted in a weekly basis in Costa Rica. In the case of the latter, the interference reaction of SO2 in the cathode cell of the standard electrochemical concentration cell (ECC) ozonesonde results in apparent "notches" in the ozone profile at the altitudes of the plume. In this paper, we present an overview of the Ticosonde observations and correlate the appearance of the notches with air mass back trajectory calculations that link the profiles features to emissions from the volcano. In addition, during February 2012, we deployed the dual O3/SO2 sonde from the University of Costa Rica and detected a plume of SO2 linked by back trajectory calcluations to Turrialba as well as an urban plume resulting from diesel exhaust in the boundary layer. The integrated column SO2 from the sonde profile data agree well with the OMI overpass data for this event. Data from a tethersonde measurement two days prior to the dual sonde reveal concentrations at the ppm level at the volcanic source.

Synthetic biology era: Improving antibiotic's world.

PubMed

Guzmán-Trampe, Silvia; Ceapa, Corina D; Manzo-Ruiz, Monserrat; Sánchez, Sergio

2017-06-15

The emergence of antibiotic-resistant pathogen microorganisms is problematic in the context of the current spectrum of available medication. The poor specificity and the high toxicity of some available molecules have made imperative the search for new strategies to improve the specificity and to pursue the discovery of novel compounds with increased bioactivity. Using living cells as platforms, synthetic biology has counteracted this problem by offering novel pathways to create synthetic systems with improved and desired functions. Among many other biotechnological approaches, the advances in synthetic biology have made it possible to design and construct novel biological systems in order to look for new drugs with increased bioactivity. Advancements have also been made in the redesigning of RNA and DNA molecules in order to engineer antibiotic clusters for antibiotic overexpression. As for the production of these antibacterial compounds, yeasts and filamentous fungi as well as gene therapy are utilized to enhance protein solubility. Specific delivery is achieved by creating chimeras using plant genes into bacterial hosts. Some of these synthetic systems are currently in clinical trials, proving the proficiency of synthetic biology in terms of both pharmacological activities as well as an increase in the biosafety of treatments. It is possible that we may just be seeing the tip of the iceberg, and synthetic biology applications will overpass expectations beyond our present knowledge. Copyright © 2017. Published by Elsevier Inc.

Remediation of heavy metal contaminated sites in the Venice lagoon and conterminous areas (Northern Italy)

NASA Astrophysics Data System (ADS)

Bini, Claudio; Wahsha, Mohammad; Fontana, Silvia; Maleci, Laura

2013-04-01

The lagoon of Venice and the conterminous land are affected by heavy contamination of anthropogenic origin, and for this reason the whole area has been classified as site of national interest, and must be restored. Heavy metals (As, Cd, Cr, Cu, Hg, Mn, Pb, Sb, Se, Zn) and organic compounds (IPA, PCB, Dioxine) have been identified as the main contaminants at various sites, owing to agriculture and industrial wastes discharged on soils and convoyed to the lagoon. Five case studies of soil remediation are here reported. S. Giuliano is a former palustrine area reclaimed since the 60's with various human transported materials (HTM). In this area, hot spots overpassing the reference limits for residential and green areas have been recorded for Cd, Cu, Pb, Zn and IPA. Campalto is a site bordering the Venice lagoon and subjected to oscillating water level, that enhances metal mobility; diffuse contamination by heavy metals, particularly Pb, has been recorded at this site, utilized since 30 years for military and sport (skate) activities. Marghera is dramatically famous for its numerous factories and for oil refineries that affected the lagoon sediments since the 50's. Sediments proved heavily contaminated by As (up to 137 mgkg-1), Cd (57 mgkg-1), Hg (30mgkg-1), Ni, Pb (700 mgkg-1), Zn (5818 mgkg-1). Murano is a small island where many glass factories (the most famous all over the world) are running since XIII century. Glass is stained with several metals and, moreover, some substances are used to regulate fusion temperature, purity, etc., and therefore the surrounding environment is heavily contaminated by these substances. Mean concentrations of As (429 mgkg-1), Cd (1452 mgkg-1), Pb (749 mgkg-1), Zn (1624 mgkg-1), Se (341 mgkg-1), Sb (74 mgkg-1) widely overpass the reference values for both residential and industrial areas in national guidelines. Molo Serbatoi is a former oil container currently under restoration in the port of Venice. Soil contamination by As, Hg, Zn and IPA was recorded, while groundwater proved to be contaminated by As, Cd, Cr, Hg, Pb, Cu, Se, Ni, Mn, Sb, Fe. Restoration of the studied sites has been carried out by phytoremediation with native or exotic vegetation (Fragmites australis, Juncus lacustris,Puccinellia palustris, Limonium serotinum, Salicornia glauca, Spartina maritima, Pteris vittata) or cultivated plants (Heliantus annuus, Zea mais, Brassica napus, Brassica juncea). Results are somewhat contradictory. At S. Giuliano, the exotic fern (Pteris vittata), consistently with data from current literature, showed high ability to accumulate As, particularly in aerial parts. At Campalto, native vegetation proved ineffective for phytoextraction, but suitable for phytostabilization, owing to a root barrier effect. In the lagoon sediments from Marghera, Spartina proved more effective than Fragmites to uptake metals, while cultivated plants could not survive to high heavy metal concentrations. At Murano, Pteris vittata proved highly effective to accumulate As, but also resistant to elevated concentrations of co-existing metals (Cd, Pb, Se, Zn), with clear signals of growth sufference and a drastic reduction of sorption capacity only in the presence of very high Cd concentration. At Molo Serbatoi, phytoremediation could not be applied in absence of a chelating agent (e.g. EDTA), which could enhance metal mobilization: therefore, soil has been stored, selected and finally (the most contaminated part) delivered to a landfill, while groundwater will be remediated by bioremediation techniques.

Subduction Drive of Plate Tectonics

NASA Astrophysics Data System (ADS)

Hamilton, W. B.

2003-12-01

Don Anderson emphasizes that plate tectonics is self-organizing and is driven by subduction, which rights the density inversion generated as oceanic lithosphere forms by cooling of asthenosphere from the top. The following synthesis owes much to many discussions with him. Hinge rollback is the key to kinematics, and, like the rest of actual plate behavior, is incompatible with bottom-up convection drive. Subduction hinges (which are under, not in front of, thin leading parts of arcs and overriding plates) roll back into subducting plates. The Pacific shrinks because bounding hinges roll back into it. Colliding arcs, increasing arc curvatures, back-arc spreading, and advance of small arcs into large plates also require rollback. Forearcs of overriding plates commonly bear basins which preclude shortening of thin plate fronts throughout periods recorded by basin strata (100 Ma for Cretaceous and Paleogene California). This requires subequal rates of advance and rollback, and control of both by subduction. Convergence rate is equal to rates of rollback and advance in many systems but is greater in others. Plate-related circulation probably is closed above 650 km. Despite the popularity of concepts of plumes from, and subduction into, lower mantle, there is no convincing evidence for, and much evidence against, penetration of the 650 in either direction. That barrier not only has a crossing-inhibiting negative Clapeyron slope but also is a compositional boundary between fractionated (not "primitive"), sluggish lower mantle and fertile, mobile upper mantle. Slabs sink more steeply than they dip. Slabs older than about 60 Ma when their subduction began sink to, and lie down on and depress, the 650-km discontinuity, and are overpassed, whereas younger slabs become neutrally buoyant in mid-upper mantle, into which they are mixed as they too are overpassed. Broadside-sinking old slabs push all upper mantle, from base of oceanic lithosphere down to the 650, back under shrinking oceans, forcing rapid Pacific spreading. Slabs suck forward overriding arcs and continental lithosphere, plus most subjacent mantle above the transition zone. Changes in sizes of oceans result primarily from transfer of oceanic lithosphere, so backarcs and expanding oceans spread only slowly. Lithosphere parked in, or displaced from, the transition zone, or mixed into mid-upper mantle, is ultimately recycled, and regional variations in age of that submerged lithosphere may account for some regional contrasts in MORB. Plate motions make no kinematic sense in either the "hotspot" reference frame (HS; the notion of fixed plumes is easily disproved) or the no-net-rotation frame (NNR) In both, for example, many hinges roll forward, impossible with gravity drive. Subduction-drive predictions are fulfilled, and paleomagnetic data are satisfied (as they are not in HS and NNR), in the alternative framework of propulsionless Antarctica fixed relative to sluggish lower mantle. Passive ridges migrate away from Antarctica on all sides, and migration of these and other ridges permits tapping fresh asthenosphere. (HS and NNR tend to fix ridges). Ridge migration and spreading rates accord with subduction drive. All trenches roll back when allowance is made for back-arc spreading and intracontinental deformation. Africa rotates slowly toward subduction systems in the NE, instead of moving rapidly E as in HS and NNR. Stable NW Eurasia is nearly stationary, instead of also moving rapidly, and S and E Eurasian deformation relates to subduction and rollback. The Americas move Pacificward at almost the full spreading rates of passive ridges behind them. Lithosphere has a slow net westward drift. Reference: W.B. Hamilton, An alternative Earth, GSA Today, in press.

A new reference evapotranspiration surface for the National Water Census community

NASA Astrophysics Data System (ADS)

Verdin, J. P.; Hobbins, M. T.; Senay, G. B.

2012-12-01

To meet its congressional mandate to provide water managers with accurate, up-to-date, scientifically defensible reporting on the national water cycle—the National Water Census—the USGS has developed a framework for ongoing estimation of actual evapotranspiration (ET) combining both land-based and remotely sensed (R/S) drivers and is transferable to observation-scarce regions. To provide ET at Census-required resolutions (~100-1000 m), we combine (i) an operational, long-term, high-quality, scientific record of reference crop ET (ETrc), (ii) R/S land-surface temperature (LST) and reflectance at finer spatial scales but coarser temporal scales, and (iii) the USDA Annual Cropland Data Layer as a geographic mask for cropped surfaces. Our presentation motivates this new ET framework and describes its ETrc input. The ETrc is generated by the Penman-Monteith equation, driven by hourly, 0.125-degree (~12-km) NLDAS data, from Jan 1, 1979, to within five days of the present. This is the first consistently modeled, daily, continent-wide ETrc dataset that is both up-to-date and as temporally extensive. The R/S component relies on this input to provide an ETrc magnitude at coarse scale relative to the imagery. Remote sensing of LST and/or surface reflectance permits inference of ET as a fraction of ETrc. One such method used by the USGS is the Simplified Surface Energy Balance (SSEB) approach, which adapted the hot and cold pixel approach of SEBAL/METRIC; an operational version (SSEBop) calculates ET-fraction for a given pixel and combines it with ETrc to estimate and map ET on a routine basis with a high degree of consistency at multiple spatial scales. Though these imagery options have limited temporal coverage due to the time between satellite overpasses (1 to 8 days for MODIS, 16 days for Landsat), ET-fraction so derived is stable on such time scales. Thus, as ETrc varies significantly across the diurnal cycle and inter-overpass periods, it is used to track conditions during these temporal gaps, to overcome issues of cloudiness and missing satellite data. This methodology demonstrates the complementary functionalities of land-based and R/S datasets and is transposable to data-poor environments using GDAS and R/S products, as demonstrated by the global gridded time series produced by USGS for the Famine Early Warning Systems Network to support crop water balance modeling in developing countries. The continent-wide ETrc will be verified against in situ weather station networks, while a first-order, second-moment uncertainty analysis will indicate in space and time which drivers require the most attention. The verification and uncertainty analyses will underline the challenges faced in achieving the same level of accuracy in the global product and highlight the need for more station data sets in diverse hydro-climatic regions and in developing countries. The operational land-based ETrc surface will be provided by NOAA from its new National Water Center, while the assimilation with R/S data will be conducted at USGS EROS and by cooperators. To meet the needs of the Census, USGS hopes to partner with those who might also be using R/S ET to estimate crop water use for administration of interstate compacts, state water rights, water supply management, and research.

Sun and Sky Radiance Measurements and Data Analysis Protocols. Chapter 5

NASA Technical Reports Server (NTRS)

Frouin, Robert; Holben, Brent; Miller, Mark; Pietras, Christophe; Porter, John; Voss, Ken

2001-01-01

This chapter is concerned with two types of radiometric measurements essential to verify atmospheric correction algorithms and to calibrate vicariously satellite ocean color sensors. The first type is a photometric measurement of the direct solar beam to determine the optical thickness of the atmosphere. The intensity of the solar beam can be measured directly, or obtained indirectly from measurements of diffuse global upper hemispheric irradiance. The second type is a measurement of the solar aureole and sky radiance distribution using a CCD camera, or a scanning radiometer viewing in and perpendicular to the solar principal plane. From the two types of measurements, the optical properties of aerosols, highly variable in space and time, can be derived. Because of the high variability, the aerosol properties should be known at the time of satellite overpass. Atmospheric optics measurements, however, are not easy to perform at sea, from a ship or any platform. This complicates the measurement protocols and data analysis. Some instrumentation cannot be deployed at sea, and is limited to island and coastal sites. In the following, measurement protocols are described for radiometers commonly used to measure direct atmospheric transmittance and sky radiance, namely standard sun photometers, fast-rotating shadow-band radiometers, automated sky scanning systems, and CCD cameras. Methods and procedures to analyze and quality control the data are discussed, as well as proper measurement strategies for evaluation of atmospheric correction algorithms and satellite-derived ocean color.

Quantifying the radiative and microphysical impacts of fire aerosols on cloud dynamics in the tropics using temporally offset satellite observations

NASA Astrophysics Data System (ADS)

Tosca, M. G.; Diner, D. J.; Garay, M. J.; Kalashnikova, O.

2013-12-01

Anthropogenic fires in Southeast Asia and Central America emit smoke that affects cloud dynamics, meteorology, and climate. We measured the cloud response to direct and indirect forcing from biomass burning aerosols using aerosol retrievals from the Multi-angle Imaging SpectroRadiometer (MISR) and non-synchronous cloud retrievals from the MODerate resolution Imaging Spectroradiometer (MODIS) from collocated morning and afternoon overpasses. Level 2 data from thirty-one individual scenes acquired between 2006 and 2010 were used to quantify changes in cloud fraction, cloud droplet size, cloud optical depth and cloud top temperature from morning (10:30am local time) to afternoon (1:30pm local time) in the presence of varying aerosol burdens. We accounted for large-scale meteorological differences between scenes by normalizing observed changes to the mean difference per individual scene. Elevated AODs reduced cloud fraction and cloud droplet size and increased cloud optical depths in both Southeast Asia and Central America. In mostly cloudy regions, aerosols significantly reduced cloud fraction and cloud droplet sizes, but in clear skies, cloud fraction, cloud optical thickness and cloud droplet sizes increased. In clouds with vertical development, aerosols reduced cloud fraction via semi-direct effects but spurred cloud growth via indirect effects. These results imply a positive feedback loop between anthropogenic burning and cloudiness in both Central America and Southeast Asia, and are consistent with previous studies linking smoke aerosols to both cloud reduction and convective invigoration.

Comparison of Ozone Retrievals from the Pandora Spectrometer System and Dobson Spectrophotometer in Boulder, Colorado

NASA Technical Reports Server (NTRS)

Herman, J.; Evans, R.; Cede, A.; Abuhassan, N.; Petropavlovskikh, I.; McConville, G.

2015-01-01

A comparison of retrieved total column ozone (TCO) amounts between the Pandora #34 spectrometer system and the Dobson #061 spectrophotometer from direct-sun observations was performed on the roof of the Boulder, Colorado, NOAA building. This paper, part of an ongoing study, covers a 1-year period starting on 17 December 2013. Both the standard Dobson and Pandora TCO retrievals required a correction, TCO(sub corr) = TCO (1 + C(T)), using a monthly varying effective ozone temperature, T(sub E), derived from a temperature and ozone profile climatology. The correction is used to remove a seasonal difference caused by using a fixed temperature in each retrieval algorithm. The respective corrections C(T(sub E)) are C(sub Pandora) = 0.00333(T(sub E) - 225) and C(sub Dobson) = -0.0013(T(sub E) - 226.7) per degree K. After the applied corrections removed most of the seasonal retrieval dependence on ozone temperature, TCO agreement between the instruments was within 1% for clear-sky conditions. For clear-sky observations, both co-located instruments tracked the day-to-day variation in total column ozone amounts with a correlation of r(exp 2) = 0.97 and an average offset of 1.1 +/- 5.8 DU. In addition, the Pandora TCO data showed 0.3% annual average agreement with satellite overpass data from AURA/OMI (Ozone Monitoring Instrument) and 1% annual average offset with Suomi-NPP/OMPS (Suomi National Polar-orbiting Partnership, the nadir viewing portion of the Ozone Mapper Profiler Suite).

Validating MODIS above-cloud aerosol optical depth retrieved from "color ratio" algorithm using direct measurements made by NASA's airborne AATS and 4STAR sensors

NASA Astrophysics Data System (ADS)

Jethva, Hiren; Torres, Omar; Remer, Lorraine; Redemann, Jens; Livingston, John; Dunagan, Stephen; Shinozuka, Yohei; Kacenelenbogen, Meloe; Segal Rosenheimer, Michal; Spurr, Rob

2016-10-01

We present the validation analysis of above-cloud aerosol optical depth (ACAOD) retrieved from the "color ratio" method applied to MODIS cloudy-sky reflectance measurements using the limited direct measurements made by NASA's airborne Ames Airborne Tracking Sunphotometer (AATS) and Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) sensors. A thorough search of the airborne database collection revealed a total of five significant events in which an airborne sun photometer, coincident with the MODIS overpass, observed partially absorbing aerosols emitted from agricultural biomass burning, dust, and wildfires over a low-level cloud deck during SAFARI-2000, ACE-ASIA 2001, and SEAC4RS 2013 campaigns, respectively. The co-located satellite-airborne matchups revealed a good agreement (root-mean-square difference < 0.1), with most matchups falling within the estimated uncertainties associated the MODIS retrievals (about -10 to +50 %). The co-retrieved cloud optical depth was comparable to that of the MODIS operational cloud product for ACE-ASIA and SEAC4RS, however, higher by 30-50 % for the SAFARI-2000 case study. The reason for this discrepancy could be attributed to the distinct aerosol optical properties encountered during respective campaigns. A brief discussion on the sources of uncertainty in the satellite-based ACAOD retrieval and co-location procedure is presented. Field experiments dedicated to making direct measurements of aerosols above cloud are needed for the extensive validation of satellite-based retrievals.

How to deal with the Poisson-gamma model to forecast patients' recruitment in clinical trials when there are pauses in recruitment dynamic?

PubMed

Minois, Nathan; Savy, Stéphanie; Lauwers-Cances, Valérie; Andrieu, Sandrine; Savy, Nicolas

2017-03-01

Recruiting patients is a crucial step of a clinical trial. Estimation of the trial duration is a question of paramount interest. Most techniques are based on deterministic models and various ad hoc methods neglecting the variability in the recruitment process. To overpass this difficulty the so-called Poisson-gamma model has been introduced involving, for each centre, a recruitment process modelled by a Poisson process whose rate is assumed constant in time and gamma-distributed. The relevancy of this model has been widely investigated. In practice, rates are rarely constant in time, there are breaks in recruitment (for instance week-ends or holidays). Such information can be collected and included in a model considering piecewise constant rate functions yielding to an inhomogeneous Cox model. The estimation of the trial duration is much more difficult. Three strategies of computation of the expected trial duration are proposed considering all the breaks, considering only large breaks and without considering breaks. The bias of these estimations procedure are assessed by means of simulation studies considering three scenarios of breaks simulation. These strategies yield to estimations with a very small bias. Moreover, the strategy with the best performances in terms of prediction and with the smallest bias is the one which does not take into account of breaks. This result is important as, in practice, collecting breaks data is pretty hard to manage.

Estimation of evapotranspiration for different land covers in a Brazilian semi-arid region: A case study of the Brígida River basin, Brazil

NASA Astrophysics Data System (ADS)

Santos, Celso Augusto Guimarães; Silva, Richarde Marques da; Silva, Alexandro Medeiros; Brasil Neto, Reginaldo Moura

2017-03-01

In this study, the Surface Energy Balance Algorithm for Land (SEBAL) was used to compute the surface albedo, vegetation indices (NDVI, SAVI and LAI), surface temperature, soil heat flux and evapotranspiration (ET) over two contrasting years (dry and wet) in the Brígida River basin, a semi-arid region of north-eastern Brazil. The actual ET was computed during satellite overpass and was integrated for 24 h on a pixel-by-pixel basis for the daily ET distribution. Due to the topographic effects, an attempt was also made to incorporate DEM information to estimate the net radiation. The land cover types identified in the watershed are cropland, bare land, dense canopy, grassland, and caatinga vegetation. In order to study the variation among the biophysical parameters and ET, two-way analysis of variance (ANOVA) was used. The ET calculated by SEBAL ranged between 2.46 and 6.87 mm/day for the dry year (1990) and 1.31 and 6.84 mm/day for the wet year (2009) for the river basin. The results showed that a reduction in vegetation cover is evident in the temporal and spatial analysis over the studied periods in the region and that these facts influence the values of the energy balance and ET. The results showed significant differences in the variables of land cover type and year at the probability level of 0.05 for all land cover types.

Direct Torque Control of a Small Wind Turbine with a Sliding-Mode Speed Controller

NASA Astrophysics Data System (ADS)

Sri Lal Senanayaka, Jagath; Karimi, Hamid Reza; Robbersmyr, Kjell G.

2016-09-01

In this paper. the method of direct torque control in the presence of a sliding-mode speed controller is proposed for a small wind turbine being used in water heating applications. This concept and control system design can be expanded to grid connected or off-grid applications. Direct torque control of electrical machines has shown several advantages including very fast dynamics torque control over field-oriented control. Moreover. the torque and flux controllers in the direct torque control algorithms are based on hvsteretic controllers which are nonlinear. In the presence of a sliding-mode speed control. a nonlinear control system can be constructed which is matched for AC/DC conversion of the converter that gives fast responses with low overshoots. The main control objectives of the proposed small wind turbine can be maximum power point tracking and soft-stall power control. This small wind turbine consists of permanent magnet synchronous generator and external wind speed. and rotor speed measurements are not required for the system. However. a sensor is needed to detect the rated wind speed overpass events to activate proper speed references for the wind turbine. Based on the low-cost design requirement of small wind turbines. an available wind speed sensor can be modified. or a new sensor can be designed to get the required measurement. The simulation results will be provided to illustrate the excellent performance of the closed-loop control system in entire wind speed range (4-25 m/s).

Satellite remote sensing of particulate matter air quality: the cloud-cover problem.

PubMed

Christopher, Sundar A; Gupta, Pawan

2010-05-01

Satellite assessments of particulate matter (PM) air quality that use solar reflectance methods are dependent on availability of clear sky; in other words, mass concentrations of PM less than 2.5 microm in aerodynamic diameter (PM2.5) cannot be estimated from satellite observations under cloudy conditions or bright surfaces such as snow/ice. Whereas most ground monitors measure PM2.5 concentrations on an hourly basis regardless of cloud conditions, space-borne sensors can only estimate daytime PM2.5 in cloud-free conditions, therefore introducing a bias. In this study, an estimate of this clear-sky bias is provided from monthly to yearly time scales over the continental United States. One year of the Moderate Resolution Imaging Spectroradiometer (MODIS) 550-nm aerosol optical depth (AOD) retrievals from Terra and Aqua satellites, collocated with 371 U.S. Environmental Protection Agency (EPA) ground monitors, have been analyzed. The results indicate that the mean differences between PM2.5 reported by ground monitors and PM2.5 calculated from ground monitors during the satellite overpass times during cloud-free conditions are less than +/- 2.5 microg m(-3), although this value varies by season and location. The mean differences are not significant as calculated by t tests (alpha = 0.05). On the basis of this analysis, it is concluded that for the continental United States, cloud cover is not a major problem for inferring monthly to yearly PM2.5 from space-borne sensors.

Assessment of SNPP VIIRS VIS NIR Radiometric Calibration Stability Using Aqua MODIS and Invariant Surface Targets

NASA Technical Reports Server (NTRS)

Wu, Aisheng; Xiong, Xiaoxiong; Cao, Changyong; Chiang, Kwo-Fu

2016-01-01

The first Visible Infrared Imaging Radiometer Suite (VIIRS) is onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite. As a primary sensor, it collects imagery and radiometric measurements of the land, atmosphere, cryosphere, and oceans in the spectral regions from visible (VIS) to long-wave infrared. NASA's National Polar-orbiting Partnership (NPP) VIIRS Characterization Support Team has been actively involved in the VIIRS radiometric and geometric calibration to support its Science Team Principal Investigators for their independent quality assessment of VIIRS Environmental Data Records. This paper presents the performance assessment of the radiometric calibration stability of the VIIRS VIS and NIR spectral bands using measurements from SNPP VIIRS and Aqua MODIS simultaneous nadir overpasses and over the invariant surface targets at the Libya-4 desert and Antarctic Dome Concordia snow sites. The VIIRS sensor data records (SDRs) used in this paper are reprocessed by the NASA SNPP Land Product Evaluation and Analysis Tool Element. This paper shows that the reprocessed VIIRS SDRs have been consistently calibrated from the beginning of the mission, and the calibration stability is similar to or better than MODIS. Results from different approaches indicate that the calibrations of the VIIRS VIS and NIR spectral bands are maintained to be stable to within 1% over the first three-year mission. The absolute calibration differences between VIIRS and MODIS are within 2%, with an exception for the 0.865-m band, after correction of their spectral response differences.

The extratropical transition of Tropical Storm Cindy from a GLM, ISS LIS and GPM perspective

NASA Astrophysics Data System (ADS)

Heuscher, L.; Gatlin, P. N.; Petersen, W. A.; Liu, C.; Cecil, D. J.

2017-12-01

The distribution of lightning with respect to tropical convective precipitation systems has been well established in previous studies, and more recently by the successful Tropical Rainfall Measuring Mission (TRMM). However, TRMM did not provide information about precipitation features pole-ward of ±38° latitude. Hence not much is known about the evolution of lightning within extra-tropical cyclones traversing the mid-latitudes, especially its oceans. To facilitate such studies we have combined lightning data from the Geostationary Lightning Mapper (GLM) onboard GOES-16 and the Lightning Imaging Sensor (LIS) onboard the International Space Station (ISS) together with precipitation features obtained from the Global Precipitation Measurement (GPM) mission constellation of satellites. We used this lightning-enriched precipitation feature dataset to investigate the lightning and precipitation characteristics of Tropical Storm Cindy (20 June - 24 June 2017) from its organization in the central Gulf of Mexico to its landfall along the northern Gulf and transition to an extra-tropical cyclone. We analyzed lightning observations from GLM and ISS LIS in relation to microwave brightness temperatures from GPM constellation satellite overpasses of Cindy. We find that the 37 and 89 GHz brightness temperatures decreased as Cindy strengthened and continued to decrease after landfall and as Cindy took on more baroclinic characteristics during which time its overall lightning activity increased by a factor of six. In this regard, the study provides a new observationally-based view of the tropical to extra-tropical transition and its impact on lightning production.

Project S'COOL

NASA Technical Reports Server (NTRS)

Green, Carolyn J.; Chambers, Lin H.

1998-01-01

The Students Clouds Observations On-Line or S'COOL project was piloted in 1997. It was created with the idea of using students to serve as one component of the validation for the Clouds and the Earth's Radiant Energy System (CERES) instrument which was launched with the Tropical Rainfall Measuring Mission (TRMM) in November, 1997. As part of NASA's Earth Science Enterprise CERES is interested in the role clouds play in regulating our climate. Over thirty schools became involved in the initial thrust of the project. The CERES instrument detects the location of clouds and identifies their physical properties. S'COOL students coordinate their ground truth observations with the exact overpass of the satellite at their location. Their findings regarding cloud type, height, fraction and opacity as well as surface conditions are then reported to the NASA Langley Distributed Active Archive Center (DAAC). The data is then accessible to both the CERES team for validation and to schools for educational application via the Internet. By March of 1998 ninety-three schools, in nine countries had enrolled in the S'COOL project. Joining the United States participants were from schools in Australia, Canada, France, Germany, Norway, Spain, Sweden, and Switzerland. The project is gradually becoming the global project envisioned by the project s creators. As students obtain the requested data useful for the scientists, it was hoped that students with guidance from their instructors would have opportunity and motivation to learn more about clouds and atmospheric science as well.

Spatial-temporal variability of precipitation in Mountainous Regions in the Southern Appalachians

NASA Astrophysics Data System (ADS)

Prat, O. P.; Barros, A. P.

2009-09-01

The purpose of this work is to investigate the mechanisms of mountainous precipitation and specifically to quantify the influence of the topography on the modification of microphysical and dynamical processes of large weather systems or on the onset of localized convective storms. Three measurement campaigns involving the deployment of one (July-August 2008) or two (October-November 2008, and June-July 2009) Micro Rain Radars (MMR) were conducted in the Great Smoky Mountains National Park (GSMNP) in the Southern Appalachians, with the goal to provide microphysical observations. Here we focus on the characterization of the diurnal cycle of rainfall and the yearly repartition of precipitation both from MRR records and from more than 30 rain gauges deployed from mid- to high-elevation along exposed ridges in the vicinity of the MRR deployment sites. A particular attention is paid to the quantification of space-time patterns of orographic enhancements between valley and ridge locations for the MRR deployment sites. The second aspect of this work, concerns a comparison of raingauge and vertically pointing radars (MRR) records with TRMM 2A25 precipitation products. A long term (from 6 months to more than two years and depending on the rain gauge installation) systematic statistical analysis is performed in order to quantify differences between ground based and remotely sensed observations for precipitation events at the time of satellite overpass. The presentation will provide a synthesis of data analysis and sensor intercomparison.

Can Population-Level Laterality Stem from Social Pressures? Evidence from Cheek Kissing in Humans

PubMed Central

Chapelain, Amandine; Pimbert, Pauline; Aube, Lydiane; Perrocheau, Océane; Debunne, Gilles; Bellido, Alain; Blois-Heulin, Catherine

2015-01-01

Despite extensive research, the origins and functions of behavioural laterality remain largely unclear. One of the most striking unresolved issues is the fact that laterality generally occurs at the population-level. Why would the majority of the individuals of a population exhibit the same laterality, while individual-level laterality would yet provide the advantages in terms of improving behavioural efficiency? Are social pressures the key factor? Can social pressures induce alignment of laterality between the individuals of a population? Can the effect of social pressures overpass the effect of other possible determining factors (e.g. genes)? We tested this important new hypothesis in humans, for the first time. We asked whether population-level laterality could stem from social pressures. Namely, we assessed social pressures on laterality in an interactive social behaviour: kissing on the cheek as a greeting. We performed observations in 10 cities of France. The observations took place in spots where people of the city meet and greet each other. We showed that: a) there is a population-level laterality for cheek kissing, with the majority of individuals being aligned in each city, and b) there is a variation between populations, with a laterality that depends on the city. These results were confirmed by our complementary data from questionnaires and internet surveys. These findings show that social pressures are involved in determining laterality. They demonstrate that population-level laterality can stem from social pressures. PMID:26270648

Can Population-Level Laterality Stem from Social Pressures? Evidence from Cheek Kissing in Humans.

PubMed

Chapelain, Amandine; Pimbert, Pauline; Aube, Lydiane; Perrocheau, Océane; Debunne, Gilles; Bellido, Alain; Blois-Heulin, Catherine

2015-01-01

Despite extensive research, the origins and functions of behavioural laterality remain largely unclear. One of the most striking unresolved issues is the fact that laterality generally occurs at the population-level. Why would the majority of the individuals of a population exhibit the same laterality, while individual-level laterality would yet provide the advantages in terms of improving behavioural efficiency? Are social pressures the key factor? Can social pressures induce alignment of laterality between the individuals of a population? Can the effect of social pressures overpass the effect of other possible determining factors (e.g. genes)? We tested this important new hypothesis in humans, for the first time. We asked whether population-level laterality could stem from social pressures. Namely, we assessed social pressures on laterality in an interactive social behaviour: kissing on the cheek as a greeting. We performed observations in 10 cities of France. The observations took place in spots where people of the city meet and greet each other. We showed that: a) there is a population-level laterality for cheek kissing, with the majority of individuals being aligned in each city, and b) there is a variation between populations, with a laterality that depends on the city. These results were confirmed by our complementary data from questionnaires and internet surveys. These findings show that social pressures are involved in determining laterality. They demonstrate that population-level laterality can stem from social pressures.

Comparison of ozone retrievals from the Pandora spectrometer system and Dobson spectrophotometer in Boulder, Colorado

NASA Astrophysics Data System (ADS)

Herman, J.; Evans, R.; Cede, A.; Abuhassan, N.; Petropavlovskikh, I.; McConville, G.

2015-08-01

A comparison of retrieved total column ozone (TCO) amounts between the Pandora #34 spectrometer system and the Dobson #061 spectrophotometer from direct-sun observations was performed on the roof of the Boulder, Colorado, NOAA building. This paper, part of an ongoing study, covers a 1-year period starting on 17 December 2013. Both the standard Dobson and Pandora TCO retrievals required a correction, TCOcorr = TCO (1 + C(T)), using a monthly varying effective ozone temperature, TE, derived from a temperature and ozone profile climatology. The correction is used to remove a seasonal difference caused by using a fixed temperature in each retrieval algorithm. The respective corrections C(TE) are CPandora = 0.00333(TE-225) and CDobson = -0.0013(TE-226.7) per degree K. After the applied corrections removed most of the seasonal retrieval dependence on ozone temperature, TCO agreement between the instruments was within 1 % for clear-sky conditions. For clear-sky observations, both co-located instruments tracked the day-to-day variation in total column ozone amounts with a correlation of r2 = 0.97 and an average offset of 1.1 ± 5.8 DU. In addition, the Pandora TCO data showed 0.3 % annual average agreement with satellite overpass data from AURA/OMI (Ozone Monitoring Instrument) and 1 % annual average offset with Suomi-NPP/OMPS (Suomi National Polar-orbiting Partnership, the nadir viewing portion of the Ozone Mapper Profiler Suite).

Monitoring the urban expansion of Athens using remote sensing and GIS techniques in the last 35 years

NASA Astrophysics Data System (ADS)

Nikolakopoulos, Konstantinos; Pavlopoulos, Kosmas; Chalkias, Christos; Manou, Dora

2005-10-01

During the last thirty-five years the capital of Greece has suffered from an enormous internal immigration. Its population has overpassed the five millions and today almost the half population of Greece is squeezed in Athens metropolitan area. Because of the significant increase of population, the urban expansion in the basin of Athens was also excessive and in some cases catastrophic. Buildings have covered all the free places, new roads have been constructed, the drainage networks have been covered or disappeared and a lot of changes have been occurred to the landforms. The construction of the new airport (Elefterios Venizelos) at the beginning of this decade created a new commercial and urban pole at the eastern part of Athens and the constructive activity has been moved to new areas around the airport. Our aim was to detect and map all the changes that occurred in the urban area, estimate the urban expansion rate and the human interferences in the natural landscape, using GIS and remote sensing techniques. We have used satellite images from three different periods (1973, 1992, 2002) and topographic maps of 1:25.000 scale. The spatial resolution of all the satellite images ranges from 5 to 10 meters and is it acceptable for the monitoring and mapping of the urban growth. Supervised classification and on screen digitizing methods have been used in order to map the changes. Finally the qualitative and quantitative results of this study are presented in this paper.

Monitoring gap junctional communication in astrocytes from acute adult mouse brain slices using the gap-FRAP technique.

PubMed

Yi, Chenju; Teillon, Jérémy; Koulakoff, Annette; Berry, Hugues; Giaume, Christian

2018-06-01

Intercellular communication through gap junction channels plays a key role in cellular homeostasis and in synchronizing physiological functions, a feature that is modified in number of pathological situations. In the brain, astrocytes are the cell population that expresses the highest amount of gap junction proteins, named connexins. Several techniques have been used to assess the level of gap junctional communication in astrocytes, but so far they remain very difficult to apply in adult brain tissue. Here, using specific loading of astrocytes with sulforhodamine 101, we adapted the gap-FRAP (Fluorescence Recovery After Photobleaching) to acute hippocampal slices from 9 month-old adult mice. We show that gap junctional communication monitored in astrocytes with this technique was inhibited either by pharmacological treatment with a gap junctional blocker or in mice lacking the two main astroglial connexins, while a partial inhibition was measured when only one connexin was knocked-out. We validate this approach using a mathematical model of sulforhodamine 101 diffusion in an elementary astroglial network and a quantitative analysis of the exponential fits to the fluorescence recovery curves. Consequently, we consider that the adaptation of the gap-FRAP technique to acute brain slices from adult mice provides an easy going and valuable approach that allows overpassing this age-dependent obstacle and will facilitate the investigation of gap junctional communication in adult healthy or pathological brain. Copyright © 2018 Elsevier B.V. All rights reserved.

Uncertainty Quantification of GEOS-5 L-band Radiative Transfer Model Parameters Using Bayesian Inference and SMOS Observations

NASA Technical Reports Server (NTRS)

DeLannoy, Gabrielle J. M.; Reichle, Rolf H.; Vrugt, Jasper A.

2013-01-01

Uncertainties in L-band (1.4 GHz) radiative transfer modeling (RTM) affect the simulation of brightness temperatures (Tb) over land and the inversion of satellite-observed Tb into soil moisture retrievals. In particular, accurate estimates of the microwave soil roughness, vegetation opacity and scattering albedo for large-scale applications are difficult to obtain from field studies and often lack an uncertainty estimate. Here, a Markov Chain Monte Carlo (MCMC) simulation method is used to determine satellite-scale estimates of RTM parameters and their posterior uncertainty by minimizing the misfit between long-term averages and standard deviations of simulated and observed Tb at a range of incidence angles, at horizontal and vertical polarization, and for morning and evening overpasses. Tb simulations are generated with the Goddard Earth Observing System (GEOS-5) and confronted with Tb observations from the Soil Moisture Ocean Salinity (SMOS) mission. The MCMC algorithm suggests that the relative uncertainty of the RTM parameter estimates is typically less than 25 of the maximum a posteriori density (MAP) parameter value. Furthermore, the actual root-mean-square-differences in long-term Tb averages and standard deviations are found consistent with the respective estimated total simulation and observation error standard deviations of m3.1K and s2.4K. It is also shown that the MAP parameter values estimated through MCMC simulation are in close agreement with those obtained with Particle Swarm Optimization (PSO).

Calibration, navigation, and registration of MAMS data for FIFE

NASA Technical Reports Server (NTRS)

Jedlovec, G. J.; Atkinson, R. J.

1993-01-01

The International Satellite Land Surface Climatology Project (ISLSCP) was conducted to study the interaction of the atmosphere with the land surface and the research problems associated with the interpretation of satellite data over the Earth's land surface. The experimental objectives of the First ISLSCP Field Experiment (FIFE) were the simultaneous acquisition of satellite, atmospheric, and surface data and to use these data to understand the processes controlling energy/mass exchange at the surface. The experiment site is a 15 x 15 km area southeast of Manhattan, Kansas, intersected by Interstate 70 and Kansas highway 177. The Konza Prairie portion is 5 x 5 km and is a controlled experiment site consisting primarily of native tall grass prairie vegetation. The remainder of the site is grazing and farm land with trees along creek beds that are scattered over the area. Airborne multispectral imagery from the Multispectral Atmospheric Mapping Sensor (MAMS) was collected over this region on two days during Intensive Field Campaign-1 (1FC-1) to study the time and space variability of remotely-sensed geophysical parameters. These datasets consist of multiple overflights covering about a 60-min period during late morning on June 4, 1987 and shortly after dark on the following day. Image data from each overpass were calibrated and Earth located with respect to each other using aircraft inertial navigation system parameters and ground control points. These were the first MAMS flights made with 10-bit thermal data.

Attenuation by clouds of UV radiation for low stratospheric ozone conditions

NASA Astrophysics Data System (ADS)

Orte, Facundo; Wolfram, Elian; Salvador, Jacobo; D'Elia, Raúl; Quiroga, Jonathan; Quel, Eduardo; Mizuno, Akira

2017-02-01

Stratospheric poor ozone air masses related to the polar ozone hole overpass subpolar regions in the Southern Hemisphere during spring and summer seasons, resulting in increases of surface Ultraviolet Index (UVI). The impact of these abnormal increases in the ultraviolet radiation could be overestimated if clouds are not taking into account. The aim of this work is to determine the percentage of cases in which cloudiness attenuates the high UV radiation that would reach the surface in low total ozone column situations and in clear sky hypothetical condition for Río Gallegos, Argentina. For this purpose, we analysed UVI data obtained from a multiband filter radiometer GUV-541 (Biospherical Inc.) installed in the Observatorio Atmosférico de la Patagonia Austral (OAPA-UNIDEF (MINDEF - CONICET)) (51 ° 33' S, 69 ° 19' W), Río Gallegos, since 2005. The database used covers the period 2005-2012 for spring seasons. Measured UVI values are compared with UVI calculated using a parametric UV model proposed by Madronich (2007), which is an approximation for the UVI for clear sky, unpolluted atmosphere and low surface albedo condition, using the total ozone column amount, obtained from the OMI database for our case, and the solar zenith angle. It is observed that ˜76% of the total low ozone amount cases, which would result in high and very high UVI categories for a hypothetical (modeled) clear sky condition, are attenuated by clouds, while 91% of hypothetical extremely high UVI category are also attenuated.

Geostationary Enhanced Temporal Interpolation for CERES Flux Products

NASA Technical Reports Server (NTRS)

Doelling, David R.; Loeb, Norman G.; Keyes, Dennis F.; Nordeen, Michele L.; Morstad, Daniel; Nguyen, Cathy; Wielicki, Bruce A.; Young, David F.; Sun, Moguo

2013-01-01

The Clouds and the Earth's Radiant Energy System (CERES) instruments on board the Terra and Aqua spacecraft continue to provide an unprecedented global climate record of the earth's top-of-atmosphere (TOA) energy budget since March 2000. A critical step in determining accurate daily averaged flux involves estimating the flux between CERES Terra or Aqua overpass times. CERES employs the CERES-only (CO) and the CERES geostationary (CG) temporal interpolation methods. The CO method assumes that the cloud properties at the time of the CERES observation remain constant and that it only accounts for changes in albedo with solar zenith angle and diurnal land heating, by assuming a shape for unresolved changes in the diurnal cycle. The CG method enhances the CERES data by explicitly accounting for changes in cloud and radiation between CERES observation times using 3-hourly imager data from five geostationary (GEO) satellites. To maintain calibration traceability, GEO radiances are calibrated against Moderate Resolution Imaging Spectroradiometer (MODIS) and the derived GEO fluxes are normalized to the CERES measurements. While the regional (1 deg latitude x 1 deg longitude) monthly-mean difference between the CG and CO methods can exceed 25 W m(sub -2) over marine stratus and land convection, these regional biases nearly cancel in the global mean. The regional monthly CG shortwave (SW) and longwave (LW) flux uncertainty is reduced by 20%, whereas the daily uncertainty is reduced by 50% and 20%, respectively, over the CO method, based on comparisons with 15-min Geostationary Earth Radiation Budget (GERB) data.

Thirty Years of Cloud Cover Patterns from Satellite Data: Fog in California's Central Valley and Coast

NASA Astrophysics Data System (ADS)

Waller, E.; Baldocchi, D. D.

2012-12-01

In an effort to assess long term trends in winter fog in the Central Valley of California, custom maps of daily cloud cover from an approximately 30 year record of AVHRR (1981-1999) and MODIS (2000-2012) satellite data were generated. Spatial rules were then used to differentiate between fog and general cloud cover. Differences among the sensors (e.g., spectral content, spatial resolution, overpass time) presented problems of consistency, but concurrent climate station data were used to resolve systematic differences in products, and to confirm long term trends. The frequency and extent of Central Valley ("Tule") fog appear to have some periodic oscillation, but also appear to be on the decline, especially in the Sacramento Valley and in the "shoulder" months of November and February. These results may have strong implications for growers of fruit and nut trees in the Central Valley dependent on winter chill hours that are augmented by the foggy daytime conditions. Conclusions about long term trends in fog are limited to daytime patterns, as results are primarily derived from reflectance-based products. Similar analyses of daytime cloud cover are performed on other areas of concern, such as the coastal fog belt of California. Large area and long term patterns here appear to have periodic oscillation similar to that for the Central Valley. However, the relatively coarse spatial resolution of the AVHRR LTDR (Long Term Data Record) data (~5-km) may be limiting for fine-scale analysis of trends.

Shipboard Measurements During ACE-Asia: an Overview

NASA Astrophysics Data System (ADS)

Bates, T. S.; Uematsu, M.; Miura, K.

2001-12-01

Shipboard measurements of aerosol properties and related parameters were conducted from the US NOAA R/V Ronald H. Brown and the Japanese R/V Mirai (MR01-K02) during the ACE-Asia Intensive Field Program (http://saga.pmel.noaa.gov/aceasia/). The R/V Brown cruise (14 March - 20 April 2001), with scientists from 22 research institutions, included measurements across the Pacific Ocean from Hawaii to Japan, in the East China Sea and in the Sea of Japan. Measurements were coordinated with the US NSF/NCAR C-130, US CIRPAS Twin Otter, and the Australian ARA King Air Aircraft, Terra and SeaWiFS satellite overpasses, and the ground station at Hachijo, Japan. Distinct aerosol and trace gas signatures were observed from the Miyakejima volcano, the deserts of China and Mongolia, the Chang Jiang Basin, the Korean Peninsula and the islands of Japan. The R/V Mirai cruise (14 - 28 May 2001), with scientists from 10 research institutions, focused on the region east of Japan along 146.5 E from 30 N to 38 N. Enhanced concentrations of radon and super-micron aerosol were measured in a post-frontal air mass along the 146.5 E transect. Observations from a Kytoon and the NIES two-wavelength (1064 nm and 532 nm) dual-polarization lidar detected dust and sulfate aerosol plumes from the Asian continent. The vertical distribution patterns of the dust and sulfate aerosols qualitatively agreed with the model prediction by the Chemical Weather Forecasting System (CFORS).

Enhanced Soundings for Local Coupling Studies: 2015 ARM Climate Research Facility Field Campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferguson, CR; Santanello, JA; Gentine, P

2015-11-01

Matching observed diurnal cycles is a fundamental yet extremely complex test for models. High temporal resolution measurements of surface turbulent heat fluxes and boundary layer properties are required to evaluate the daytime evolution of the boundary layer and its sensitivity to land-atmosphere coupling. To address this need, (12) one-day intensive observing periods (IOP) with enhanced radiosonding will be carried out at the ARM Southern Great Plains (SGP) Central Facility (CF) during summer 2015. Each IOP will comprise a single launch to correspond with the nighttime overpass of the A-Train of satellites (~0830 UTC) and hourly launches during daytime beginning frommore » 1130 UTC and ending at 2130 UTC. At 3-hourly intervals (i.e., 1140 UTC, 1440 UTC, 1740 UTC, and 2040 UTC) a duplicate second radiosonde will be launched 10 minutes subsequent to launch of the on-hour radiosonde for the purpose of assessing horizontal atmospheric variability. In summary, each IOP will have a 14-sounding supplement to the 6-hourly operational sounding schedule at the ARM-SGP CF. The IOP days will be decided before sunset on the preceding day, according to the judgment of the PI’s and taking into consideration daily weather forecasts and the operability of complimentary ARM-SGP CF instrumentation. An overarching goal of the project is to address how ARM could better observe land-atmosphere coupling to support the evaluation and refinement of coupled weather and climate models.« less

Validating MODIS Above-Cloud Aerosol Optical Depth Retrieved from Color Ratio Algorithm Using Direct Measurements Made by NASA's Airborne AATS and 4STAR Sensors

NASA Technical Reports Server (NTRS)

Jethva, Hiren; Torres, Omar; Remer, Lorraine; Redemann, Jens; Livingston, John; Dunagan, Stephen; Shinozuka, Yohei; Kacenelenbogen, Meloe; Segal Rozenhaimer, Michal; Spurr, Rob

2016-01-01

We present the validation analysis of above-cloud aerosol optical depth (ACAOD) retrieved from the color ratio method applied to MODIS cloudy-sky reflectance measurements using the limited direct measurements made by NASAs airborne Ames Airborne Tracking Sunphotometer (AATS) and Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) sensors. A thorough search of the airborne database collection revealed a total of five significant events in which an airborne sun photometer, coincident with the MODIS overpass, observed partially absorbing aerosols emitted from agricultural biomass burning, dust, and wildfires over a low-level cloud deck during SAFARI-2000, ACE-ASIA 2001, and SEAC4RS 2013 campaigns, respectively. The co-located satellite-airborne match ups revealed a good agreement (root-mean-square difference less than 0.1), with most match ups falling within the estimated uncertainties associated with the MODIS retrievals (about -10 to +50 ). The co-retrieved cloud optical depth was comparable to that of the MODIS operational cloud product for ACE-ASIA and SEAC4RS, however, higher by 30-50% for the SAFARI-2000 case study. The reason for this discrepancy could be attributed to the distinct aerosol optical properties encountered during respective campaigns. A brief discussion on the sources of uncertainty in the satellite-based ACAOD retrieval and co-location procedure is presented. Field experiments dedicated to making direct measurements of aerosols above cloud are needed for the extensive validation of satellite based retrievals.

CloudSat Education Network: Partnerships for Outreach

NASA Astrophysics Data System (ADS)

TeBockhorst, D.

2014-12-01

CloudSat Education Network (CEN): Partnerships to improve the understanding of clouds in formal and informal settings. Since The CloudSat satellite launched in 2006 the Formal and Informal education programs for the mission have been focused on bringing an understanding about the mission science and the importance of clouds, climate & weather science. This has been done by creating and strengthening partnership and collaboration within scientific and educational communities around the country and the world. Because CloudSat was formally recognized as a Earth System Science Pathfinder campaign with the GLOBE program, the CEN developed a set of field protocols for student observations that augmented the GLOBE atmosphere protocols when there was a satellite overpass. This shared process between GLOBE & CloudSat resulted in the training & creation of CEN schools that are both GLOBE schools and CloudSat schools, and also produced three GLOBE partnerships that specialize in cloud science education and outreach. In addition, the CEN has developed productive relationships with other NASA missions and EPO teams. Specifically, in collaboration with the NASA CERES mission projects S'Cool and MyNASAData, we have co-presented at NSTA conferences and with schools participating in a NASA EPOESS-funded formal education project. This collaborative work has been a very real benefit to a wide variety of audiences needing to strengthen their understanding of clouds and their roles in the earth system, and we hope will serve as a model to future missions looking to involve the public in mission science.

Predictive models of turbidity and water depth in the Doñana marshes using Landsat TM and ETM+ images.

PubMed

Bustamante, Javier; Pacios, Fernando; Díaz-Delgado, Ricardo; Aragonés, David

2009-05-01

We have used Landsat-5 TM and Landsat-7 ETM+ images together with simultaneous ground-truth data at sample points in the Doñana marshes to predict water turbidity and depth from band reflectance using Generalized Additive Models. We have point samples for 12 different dates simultaneous with 7 Landsat-5 and 5 Landsat-7 overpasses. The best model for water turbidity in the marsh explained 38% of variance in ground-truth data and included as predictors band 3 (630-690 nm), band 5 (1550-1750 nm) and the ratio between bands 1 (450-520 nm) and 4 (760-900 nm). Water turbidity is easier to predict for water bodies like the Guadalquivir River and artificial ponds that are deep and not affected by bottom soil reflectance and aquatic vegetation. For the latter, a simple model using band 3 reflectance explains 78.6% of the variance. Water depth is easier to predict than turbidity. The best model for water depth in the marsh explains 78% of the variance and includes as predictors band 1, band 5, the ratio between band 2 (520-600 nm) and band 4, and bottom soil reflectance in band 4 in September, when the marsh is dry. The water turbidity and water depth models have been developed in order to reconstruct historical changes in Doñana wetlands during the last 30 years using the Landsat satellite images time series.

Combining Passive Microwave Sounders with CYGNSS information for improved retrievals: Observations during Hurricane Harvey

NASA Astrophysics Data System (ADS)

Schreier, M. M.

2017-12-01

The launch of CYGNSS (Cyclone Global Navigation Satellite System) has added an interesting component to satellite observations: it can provide wind speeds in the tropical area with a high repetition rate. Passive microwave sounders that are overpassing the same region can benefit from this information, when it comes to the retrieval of temperature or water profiles: the uncertainty about wind speeds has a strong impact on emissivity and reflectivity calculations with respect to surface temperature. This has strong influences on the uncertainty of retrieval of temperature and water content, especially under extreme weather conditions. Adding CYGNSS information to the retrieval can help to reduce errors and provide a significantly better sounder retrieval. Based on observations during Hurricane Harvey, we want to show the impact of CYGNSS data on the retrieval of passive microwave sensors. We will show examples on the impact on the retrieval from polar orbiting instruments, like the Advanced Technology Microwave Sounder (ATMS) and AMSU-A/B on NOAA-18 and 19. In addition we will also show the impact on retrievals from HAMSR (High Altitude MMIC Sounding Radiometer), which was flying on the Global Hawk during the EPOCH campaign. We will compare the results with other observations and estimate the impact of additional CYGNSS information on the microwave retrieval, especially on the impact in error and uncertainty reduction. We think, that a synergetic use of these different data sources could significantly help to produce better assimilation products for forecast assimilation.

A simulation study of scene confusion factors in sensing soil moisture from orbital radar

NASA Technical Reports Server (NTRS)

Ulaby, F. T. (Principal Investigator); Dobson, M. C.; Moezzi, S.; Roth, F. T.

1983-01-01

Simulated C-band radar imagery for a 124-km by 108-km test site in eastern Kansas is used to classify soil moisture. Simulated radar resolutions are 100 m by 100 m, 1 km by 1km, and 3 km by 3 km. Distributions of actual near-surface soil moisture are established daily for a 23-day accounting period using a water budget model. Within the 23-day period, three orbital radar overpasses are simulated roughly corresponding to generally moist, wet, and dry soil moisture conditions. The radar simulations are performed by a target/sensor interaction model dependent upon a terrain model, land-use classification, and near-surface soil moisture distribution. The accuracy of soil-moisture classification is evaluated for each single-date radar observation and also for multi-date detection of relative soil moisture change. In general, the results for single-date moisture detection show that 70% to 90% of cropland can be correctly classified to within +/- 20% of the true percent of field capacity. For a given radar resolution, the expected classification accuracy is shown to be dependent upon both the general soil moisture condition and also the geographical distribution of land-use and topographic relief. An analysis of cropland, urban, pasture/rangeland, and woodland subregions within the test site indicates that multi-temporal detection of relative soil moisture change is least sensitive to classification error resulting from scene complexity and topographic effects.

GOSAT field experiments with a new portable mid-IR FTS in the western US

NASA Astrophysics Data System (ADS)

Shiomi, K.; Kikuchi, N.; Kuze, A.; Suto, H.; Kawakami, S.; Hashimoto, M.; Kataoka, F.; Kasai, K.; Arai, T.; Hedelius, J.; Viatte, C.; Wennberg, P. O.; Roehl, C. M.; Leifer, I.; Yates, E. L.; Marrero, J. E.; Iraci, L. T.; Bruegge, C. J.; Schwandner, F. M.; Crisp, D.

2016-12-01

The column-average dry air mole fractions of carbon dioxide (XCO2), methane (XCH4) and carbon monoxide (XCO) were measured from the surface using direct sunlight at near-IR wavelengths. Simultaneous detection of CO is helpful to characterize CO2 source type. We measured XCO along with XCO2 and XCH4 using a new portable Fourier transform spectrometer (FTS), EM27/SUN mid-IR,in western US field experiments at 1) Caltech, in Pasadena, a northern Los Angeles suburb, 2) Chino, a dairy farming region east of Los Angeles, and 3) Railroad Valley (RRV), a desert playa in Nevada. These measurements were conducted during the GOSAT/OCO-2 joint campaign for vicarious calibration and validation (cal/val) and its preparatory experiments in the early summer of 2016. Before the campaign, measurements from the JAXA EM27/SUN mid-IR were compared with those from the Total Carbon Column Observing Network (TCCON) station at Caltech. Then, we observed a diurnal cycle at the Chino dairy site, an area of concentrated animal husbandry, producing a CH4 point source. Finally, we conducted the cal/val campaign at RRV coincident with GOSAT and OCO-2 overpass observations. Over RRV, in-situ vertical profiles of CO2 and CH4 were measured using the Alpha Jet research aircraft as a part of the NASA Ames Alpha Jet Atmospheric eXperiment (AJAX). We will compare experimental results from the cal/val campaign for XCO2 and XCH4 with the portable FTS.

NASA CYGNSS Mission Overview

NASA Astrophysics Data System (ADS)

Ruf, C. S.; Balasubramaniam, R.; Gleason, S.; McKague, D. S.; O'Brien, A.

2017-12-01

The CYGNSS constellation of eight satellites was successfully launched on 15 December 2016 into a low inclination (tropical) Earth orbit. Each satellite carries a four-channel bi-static radar receiver that measures GPS signals scattered by the ocean, from which ocean surface roughness, near surface wind speed, and air-sea latent heat flux are estimated. The measurements are unique in several respects, most notably in their ability to penetrate through all levels of precipitation, made possible by the low frequency at which GPS operates, and in the frequent sampling of tropical cyclone intensification and of the diurnal cycle of winds, made possible by the large number of satellites. Engineering commissioning of the constellation was successfully completed in March 2017 and the mission is currently in the early phase of science operations. Level 2 science data products have been developed for near surface (10 m referenced) ocean wind speed, ocean surface roughness (mean square slope) and latent heat flux. Level 3 gridded versions of the L2 products have also been developed. A set of Level 4 products have also been developed specifically for direct tropical cyclone overpasses. These include the storm intensity (peak sustained winds) and size (radius of maximum winds), its extent (34, 50 and 64 knot wind radii), and its integrated kinetic energy. Assimilation of CYGNSS L2 wind speed data into the HWRF hurricane weather prediction model has also been developed. An overview and the current status of the mission will be presented, together with highlights of early on-orbit performance and scientific results.

Assessing actual evapotranspiration via surface energy balance aiming to optimize water and energy consumption in large scale pressurized irrigation systems

NASA Astrophysics Data System (ADS)

Awada, H.; Ciraolo, G.; Maltese, A.; Moreno Hidalgo, M. A.; Provenzano, G.; Còrcoles, J. I.

2017-10-01

Satellite imagery provides a dependable basis for computational models that aimed to determine actual evapotranspiration (ET) by surface energy balance. Satellite-based models enables quantifying ET over large areas for a wide range of applications, such as monitoring water distribution, managing irrigation and assessing irrigation systems' performance. With the aim to evaluate the energy and water consumption of a large scale on-turn pressurized irrigation system in the district of Aguas Nuevas, Albacete, Spain, the satellite-based image-processing model SEBAL was used for calculating actual ET. The model has been applied to quantify instantaneous, daily, and seasonal actual ET over high- resolution Landsat images for the peak water demand season (May to September) and for the years 2006 - 2008. The model provided a direct estimation of the distribution of main energy fluxes, at the instant when the satellite overpassed over each field of the district. The image acquisition day Evapotranspiration (ET24) was obtained from instantaneous values by assuming a constant evaporative fraction (Λ) for the entire day of acquisition; then, monthly and seasonal ET were estimated from the daily evapotranspiration (ETdaily) assuming that ET24 varies in proportion to reference ET (ETr) at the meteorological station, thus accounting for day to day variation in meteorological forcing. The comparison between the hydrants water consumption and the actual evapotranspiration, considering an irrigation efficiency of 85%, showed that a considerable amount of water and energy can be saved at district level.

Observations of Convective Development from Repeat Pass Radiometry during CalWaters 2015: Outlook for the TEMPEST Mission

NASA Astrophysics Data System (ADS)

Brown, S. T.

2015-12-01

The Temporal Experiment for Storms and Tropical Systems (TEMPEST), which was recently selected as a NASA Earth Ventures technology demonstration mission, uses a constellation of five CubeSats flying in formation to provide observations of developing precipitation with a temporal resolution of 5 minutes. The observations are made using small mm-wave radiometers with frequencies ranging from 90 to 183 GHz which are sensitive to the integrated ice water path above the precipitation layer in the storm. This paper describes TEMPEST like observations that were made with the High Altitude MMIC Sounding Radiometer (HAMSR) on the ER-2 during CalWaters 2015. HAMSR is a mm-wave airborne radiometer with 25 channels in three bands; 50, 118 and 183 GHz. During the campaign, a small isolated area of convection was identified by the ER-2 pilot and 5 overpasses of the area were made with about 5 minutes between each pass. The HAMSR data reveal two convective cells, one which was diminishing and one which was developing. The mm-wave channels near the 183 GHz water vapor line clearly show the change in the vertical extent of the storm with time, a proxy for vertical velocity. These data demonstrate the potential for TEMPEST like observations from an orbital vantage point. This paper will provide an overview of the measurements, an analysis of the observations and offer perspectives for the TEMPEST mission.

Polar2Grid 2.0: Reprojecting Satellite Data Made Easy

NASA Astrophysics Data System (ADS)

Hoese, D.; Strabala, K.

2015-12-01

Polar-orbiting multi-band meteorological sensors such as those on the Suomi National Polar-orbiting Partnership (SNPP) satellite pose substantial challenges for taking imagery the last mile to forecast offices, scientific analysis environments, and the general public. To do this quickly and easily, the Cooperative Institute for Meteorological Satellite Studies (CIMSS) at the University of Wisconsin has created an open-source, modular application system, Polar2Grid. This bundled solution automates tools for converting various satellite products like those from VIIRS and MODIS into a variety of output formats, including GeoTIFFs, AWIPS compatible NetCDF files, and NinJo forecasting workstation compatible TIFF images. In addition to traditional visible and infrared imagery, Polar2Grid includes three perceptual enhancements for the VIIRS Day-Night Band (DNB), as well as providing the capability to create sharpened true color, sharpened false color, and user-defined RGB images. Polar2Grid performs conversions and projections in seconds on large swaths of data. Polar2Grid is currently providing VIIRS imagery over the Continental United States, as well as Alaska and Hawaii, from various Direct-Broadcast antennas to operational forecasters at the NOAA National Weather Service (NWS) offices in their AWIPS terminals, within minutes of an overpass of the Suomi NPP satellite. Three years after Polar2Grid development started, the Polar2Grid team is now releasing version 2.0 of the software; supporting more sensors, generating more products, and providing all of its features in an easy to use command line interface.

Quantifying the microphysical impacts of fire aerosols on clouds in Indonesia using remote sensing observations

NASA Astrophysics Data System (ADS)

Tosca, M. G.; Diner, D. J.; Garay, M. J.; Kalashnikova, O. V.

2012-12-01

Fire-emitted aerosols modify cloud and precipitation dynamics by acting as cloud condensation nuclei in what is known as the first and second aerosol indirect effect. The cloud response to the indirect effect varies regionally and is not well understood in the highly convective tropics. We analyzed nine years (2003-2011) of aerosol data from the Multi-angle Imaging SpectroRadiometer (MISR), and fire emissions data from the Global Fire Emissions Database, version 3 (GFED3) over southeastern tropical Asia (Indonesia), and identified scenes that contained both a high atmospheric aerosol burden and large surface fire emissions. We then collected scenes from the Cloud Profiling Radar (CPR) on board the CLOUDSAT satellite that corresponded both spatially and temporally to the high-burning scenes from MISR, and identified differences in convective cloud dynamics over areas with varying aerosol optical depths. Differences in overpass times (MISR in the morning, CLOUDSAT in the afternoon) improved our ability to infer that changes in cloud dynamics were a response to increased or decreased aerosol emissions. Our results extended conclusions from initial studies over the Amazon that used remote sensing techniques to identify cloud fraction reductions in high burning areas (Koren et al., 2004; Rosenfeld, 1999) References Koren, I., Y.J. Kaufman, L.A. Remer and J.V. Martins (2004), Measurement of the effect of Amazon smoke on inhibition of cloud formation, Science, 303, 1342-1345 Rosenfeld, D. (1999), TRMM observed first direct evidence of smoke from forest fires inhibiting rainfall, Gephys. Res. Lett., 26, 3105.

Urban seismology - Northridge aftershocks recorded by multi-scale arrays of portable digital seismographs

USGS Publications Warehouse

Meremonte, M.; Frankel, A.; Cranswick, E.; Carver, D.; Worley, D.

1996-01-01

We deployed portable digital seismographs in the San Fernando Valley (SFV), the Los Angeles basin (LAB), and surrounding hills to record aftershocks of the 17 January 1994 Northridge California earthquake. The purpose of the deployment was to investigate factors relevant to seismic zonation in urban areas, such as site amplification, sedimentary basin effects, and the variability of ground motion over short baselines. We placed seismographs at 47 sites (not all concurrently) and recorded about 290 earthquakes with magnitudes up to 5.1 at five stations or more. We deployed widely spaced stations for profiles across the San Fernando Valley, as well as five dense arrays (apertures of 200 to 500 m) in areas of high damage, such as the collapsed Interstate 10 overpass, Sherman Oaks, and the collapsed parking garage at CalState Northridge. Aftershock data analysis indicates a correlation of site amplification with mainshock damage. We found several cases where the site amplification depended on the azimuth of the aftershock, possibly indicating focusing from basin structures. For the parking garage array, we found large ground-motion variabilities (a factor of 2) over 200-m distances for sites on the same mapped soil unit. Array analysis of the aftershock seismograms demonstrates that sizable arrivals after the direct 5 waves consist of surface waves traveling from the same azimuth as that of the epicenter. These surface waves increase the duration of motions and can have frequencies as high as about 4 Hz. For the events studied here, we do not observe large arrivals reflected from the southern edge of the San Fernando Valley.

BRDF Characterization and Calibration Inter-Comparison between Terra MODIS, Aqua MODIS, and S-NPP VIIRS

NASA Technical Reports Server (NTRS)

Chang, Tiejun; Xiong, Xiaoxiong (Jack); Angal, Amit; Wu, Aisheng

2016-01-01

The inter-comparison of reflective solar bands (RSB) between Terra MODIS, Aqua MODIS, and SNPP VIIRS is very important for assessment of each instrument's calibration and to identify calibration improvements. One of the limitations of using their ground observations for the assessment is a lack of the simultaneous nadir overpasses (SNOs) over selected pseudo-invariant targets. In addition, their measurements over a selected Earth view target have significant difference in solar and view angles, and these differences magnify the effects of Bidirectional Reflectance Distribution Function (BRDF). In this work, an inter-comparison technique using a semi-empirical BRDF model is developed for reflectance correction. BRDF characterization requires a broad coverage of solar and view angles in the measurements over selected pseudo-invariant targets. Reflectance measurements over Libya 1, 2, and 4 desert sites from both the Aqua and Terra MODIS are regressed to a BRDF model with an adjustable coefficient accounting for the calibration difference between the two instruments. The BRDF coefficients for three desert sites for MODIS bands 1 to 9 are derived and the wavelength dependencies are presented. The analysis and inter-comparison are for MODIS bands 1 to 9 and VIIRS moderate resolution radiometric bands (M bands) M1, M2, M4, M5, M7, M8, M10 and imaging bands (I bands) I1-I3. Results show that the ratios from different sites are in good agreement. The ratios between Terra and Aqua MODIS from year 2003 to 2014 are presented. The inter-comparison between MODIS and VIIRS are analyzed for year 2014.

Airborne and ground based measurements in McMurdo Sound, Antarctica, for the validation of satellite derived ice thickness

NASA Astrophysics Data System (ADS)

Rack, Wolfgang; Haas, Christian; Langhorne, Pat; Leonard, Greg; Price, Dan; Barnsdale, Kelvin; Soltanzadeh, Iman

2014-05-01

Melting and freezing processes in the ice shelf cavities of the Ross and McMurdo Ice Shelves significantly influence the sea ice formation in McMurdo Sound. Between 2009 and 2013 we used a helicopter-borne laser and electromagnetic induction sounder (EM bird) to measure thickness and freeboard profiles across the ice shelf and the landfast sea ice, which was accompanied by extensive field validation, and coordinated with satellite altimeter overpasses. Using freeboard and thickness, the bulk density of all ice types was calculated assuming hydrostatic equilibrium. Significant density steps were detected between first-year and multi-year sea ice, with higher values for the younger sea ice. Values are overestimated in areas with abundance of sub-ice platelets because of overestimation in both ice thickness and freeboard. On the ice shelf, bulk ice densities were sometimes higher than that of pure ice, which can be explained by both the accretion of marine ice and glacial sediments. For thin ice, the freeboard to thickness conversion critically depends on the knowledge of snow properties. Our measurements allow tuning and validation of snow cover simulations using the Weather Research Forecasting (WRF) model. The simulated snowcover is used to calculate ice thickness from satellite derived freeboard. The results of our measurements, which are supported by the New Zealand Antarctic programme, draw a picture of how oceanographic processes influence the ice shelf morphology and sea ice formation in McMurdo Sound, and how satellite derived freeboard of ICESat and CryoSat together with information on snow cover can potentially capture the signature of these processes.

Comparison between MODIS-derived day and night cloud cover and surface observations over the North China Plain

NASA Astrophysics Data System (ADS)

Zhang, Xiao; Tan, Saichun; Shi, Guangyu

2018-02-01

Satellite and human visual observation are two of the most important observation approaches for cloud cover. In this study, the total cloud cover (TCC) observed by MODIS onboard the Terra and Aqua satellites was compared with Synop meteorological station observations over the North China Plain and its surrounding regions for 11 years during daytime and 7 years during nighttime. The Synop data were recorded eight times a day at 3-h intervals. Linear interpolation was used to interpolate the Synop data to the MODIS overpass time in order to reduce the temporal deviation between the satellite and Synop observations. Results showed that MODIS-derived TCC had good consistency with the Synop observations; the correlation coefficients ranged from 0.56 in winter to 0.73 in summer for Terra MODIS, and from 0.55 in winter to 0.71 in summer for Aqua MODIS. However, they also had certain differences. On average, the MODIS-derived TCC was 15.16% higher than the Synop data, and this value was higher at nighttime (15.58%-16.64%) than daytime (12.74%-14.14%). The deviation between the MODIS and Synop TCC had large seasonal variation, being largest in winter (29.53%-31.07%) and smallest in summer (4.46%-6.07%). Analysis indicated that cloud with low cloud-top height and small cloud optical thickness was more likely to cause observation bias. Besides, an increase in the satellite view zenith angle, aerosol optical depth, or snow cover could lead to positively biased MODIS results, and this affect differed among different cloud types.

A Novel Method to Estimate Surface NO_{2} Concentrations from the Space-borne Ozone Monitoring Instrument

NASA Astrophysics Data System (ADS)

Li, Yanshun; Zhang, Qiang; Geng, Guannan; Zheng, Yixuan; Guo, Jianping

2017-04-01

Atmospheric NO2near the surface has notable health effects and is precursor of tropospheric ozone. In this work, we propose a novel method to estimate daily surface NO2 concentrations from the Ozone Monitoring Instrument (OMI) with improved accuracy. Two chemical transport models GEOS-Chem and WRF/CMAQ are used to simulate converting factors between OMI column densities and surface concentrations. GEOS-Chem is found to better capture the distribution of converting factors, while CMAQ has advantage in simulating the magnitude. We combine the two models to calculate optimal values of converting factors and further constrain them by using colocated boundary layer heights (BLH) derived from fine-resolution sounding observations made at OMI overpass time. Calculated converting factors over Chinese Mainland vary by more than three orders of magnitude (10-18 ˜10-15 μgṡcm-1ṡmolecule-1), indicating complexity of NO2 vertical structure over large spatial extent. We generate a map of surface NO2 mass concentrations during June 2013 from OMI retrievals at 0.1˚ ×0.1˚ grids. Estimated concentrations from our novel method show reasonable spatial agreement with in situ chemiluminescent measurements (R = 0.70, Slope = 0.58, N = 353), which significantly outperform estimations using only GEOS-Chem (R = 0.60, Slope = 0.20, N = 353) or WRF/CMAQ (R = 0.19, Slope = 0.52, N = 353) to simulate the converting factor. Preliminary results show that the novel method developed in this study could improve capability of satellite sensors to quantify surface NO2 pollution.

The importance of the diurnal cycle of Aerosol Optical Depth in West Africa

NASA Astrophysics Data System (ADS)

Kocha, Cécile; Tulet, Pierre; Lafore, Jean-Philippe; Flamant, Cyrille; Banks, Jamie; Marnas, Fabien; Brindley, Helen; Marsham, Jonh

2013-04-01

High resolution atmospheric simulations with the AROME model coupled with a dust module over West Africa for the whole of June 2006 and 2011 were used to calculate Aerosol Optical Depth (AOD). But the simulations showed a significant diurnal cycle of 0.2 in the dust AOD that could not be inferred from the MODIS Deep Blue satellite retrievals due to their time of overpass. The AROME AOD diurnal cycle have been compared to the new SEVIRI AOD retrievals in June 2011 and shows simlar AOD diurnal cycle. In fact, dust sources are mainly driven by the breakdown of the early morning low-level jet and by moist convection in the afternoon, leading to opposite diurnal cycles. The contribution in dust production is calculated for each processes. Moreover, simulations show that cloud cover significantly prevents the observation of AOD in convective areas. The under-sampling of the diurnal cycle by satellites like MODIS plus the impact of cloud masks on the space-borne AOD retrievals induce an underestimation of 0.28 (~40%) over the convective regions and an overestimation of 0.1 (17%) over morning source areas like Bodélé. Finally, the vertical dust distribution is explored via CALIPSO monthly mean from 2006 to 2011. The vertical dust distribution is a clue element to determine the dust raciative impact. Over the June month, the dust radiative impact affect the atmospheric energetic budget by an absorption of the short wave of 58W/m²/AOD into the atmosphere and a reduction of 50W/m²/AOD at the surface.

Multimatrix measurement of persistent organic pollutants in Mar Chiquita, a continental saline shallow lake.

PubMed

Ballesteros, M L; Miglioranza, K S B; Gonzalez, M; Fillmann, G; Wunderlin, D A; Bistoni, M A

2014-08-15

RAMSAR sites are determined by specific characteristics of the environment in terms of ecological productivity as well services for human development, but they are also one of the most threatened ecosystems. Thus, the objective of this work was to evaluate the dynamic of Persistent Organic Pollutants (POPs) in different biotic and abiotic matrixes of the RAMSAR site (wetlands with international importance), Mar Chiquita Lake. Sampling was performed according to land use (agricultural, urban, and industrial) at two stations: Laguna del Plata and Campo Mare. POPs were analyzed in superficial water (Sw), suspended particulate material (SPM), bottom sediment (Bs) and fish tissues (Odontesthes bonariensis). Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were analyzed by GC-ECD. HCHs, Endosulfans, DDTs, PCBs and PBDEs were found in all matrixes at both stations. The high persistence and transport processes are responsible for the occurrence of HCHs, DDTs and PCBs in Bs, SPM and fish tissues, even many years after their prohibition. PBDEs showed lower levels according to the scarcity of punctual sources in the area. Endosulfan showed variable amounts in agreement with application periods since this pesticide was used until a few years ago in this area. Finally, PCB levels overpassed the acceptable daily intake for human consumption being a risk for human health Thus, the present report confirms the occurrence of POPs in Mar Chiquita lake, alerting on the contribution of agricultural and urban pollutants in a RAMSAR site. Current results also raise concerns on biomagnification processes through the food web. Copyright © 2014 Elsevier B.V. All rights reserved.

Improving Assessment of Lifetime Solar Ultraviolet Radiation Exposure in Epidemiologic Studies: Comparison of Ultraviolet Exposure Assessment Methods in a Nationwide United States Occupational Cohort.

PubMed

Little, Mark P; Tatalovich, Zaria; Linet, Martha S; Fang, Michelle; Kendall, Gerald M; Kimlin, Michael G

2018-06-13

Solar ultraviolet radiation is the primary risk factor for skin cancers and sun-related eye disorders. Estimates of individual ambient ultraviolet irradiance derived from ground-based solar measurements and from satellite measurements have rarely been compared. Using self-reported residential history from 67,189 persons in a nationwide occupational US radiologic technologists cohort, we estimated ambient solar irradiance using data from ground-based meters and noontime satellite measurements. The mean distance-moved from city of longest residence in childhood increased from 137.6 km at ages 13-19 to 870.3 km at ages ≥65, with corresponding increases in absolute latitude-difference moved. At ages 20/40/60/80, the Pearson/Spearman correlation coefficients of ground-based and satellite-derived solar potential ultraviolet exposure, using irradiance and cumulative radiant-exposure metrics, were high (=0.87-0.92). There was also moderate correlation (Pearson/Spearman correlation coefficients=0.51-0.60) between irradiance at birth and at last-known address, for ground-based and satellite data. Satellite-based lifetime estimates of ultraviolet radiation were generally 14-15% lower than ground-based estimates, albeit with substantial uncertainties, possibly because ground-based estimates incorporate fluctuations in cloud and ozone, which are incompletely incorporated in the single noontime satellite-overpass ultraviolet value. If confirmed elsewhere, the findings suggest that ground-based estimates may improve exposure-assessment accuracy and potentially provide new insights into ultraviolet-radiation-disease relationships in epidemiologic studies. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Automated River Reach Definition Strategies: Applications for the Surface Water and Ocean Topography Mission

NASA Astrophysics Data System (ADS)

Frasson, Renato Prata de Moraes; Wei, Rui; Durand, Michael; Minear, J. Toby; Domeneghetti, Alessio; Schumann, Guy; Williams, Brent A.; Rodriguez, Ernesto; Picamilh, Christophe; Lion, Christine; Pavelsky, Tamlin; Garambois, Pierre-André

2017-10-01

The upcoming Surface Water and Ocean Topography (SWOT) mission will measure water surface heights and widths for rivers wider than 100 m. At its native resolution, SWOT height errors are expected to be on the order of meters, which prevent the calculation of water surface slopes and the use of slope-dependent discharge equations. To mitigate height and width errors, the high-resolution measurements will be grouped into reaches (˜5 to 15 km), where slope and discharge are estimated. We describe three automated river segmentation strategies for defining optimum reaches for discharge estimation: (1) arbitrary lengths, (2) identification of hydraulic controls, and (3) sinuosity. We test our methodologies on 9 and 14 simulated SWOT overpasses over the Sacramento and the Po Rivers, respectively, which we compare against hydraulic models of each river. Our results show that generally, height, width, and slope errors decrease with increasing reach length. However, the hydraulic controls and the sinuosity methods led to better slopes and often height errors that were either smaller or comparable to those of arbitrary reaches of compatible sizes. Estimated discharge errors caused by the propagation of height, width, and slope errors through the discharge equation were often smaller for sinuosity (on average 8.5% for the Sacramento and 6.9% for the Po) and hydraulic control (Sacramento: 7.3% and Po: 5.9%) reaches than for arbitrary reaches of comparable lengths (Sacramento: 8.6% and Po: 7.8%). This analysis suggests that reach definition methods that preserve the hydraulic properties of the river network may lead to better discharge estimates.

multi-dimensional Cloud-aERosol Exploratory Study using RPAS (mCERES): Bottom-up and top-down closure of aerosol-cloud interactions

NASA Astrophysics Data System (ADS)

Roberts, Greg; Calmer, Radiance; Sanchez, Kevin; Cayez, Grégoire; Nicoll, Kerianne; Hashimshoni, Eyal; Rosenfeld, Daniel; Ansmann, Albert; Sciare, Jean; Ovadneite, Jurgita; Bronz, Murat; Hattenberger, Gautier; Preissler, Jana; Buehl, Johannes; Ceburnis, Darius; O'Dowd, Colin

2016-04-01

Clouds are omnipresent in earth's atmosphere and constitute an important role in regulating the radiative budget of the planet. However, the response of clouds to climate change remains uncertain, in particular, with respect to aerosol-cloud interactions and feedback mechanisms between the biosphere and atmosphere. Aerosol-cloud interactions and their feedbacks are the main themes of the European project FP7 BACCHUS (Impact of Biogenic versus Anthropogenic Emissions on Clouds and Climate: towards a Holistic Understanding). The National Center for Meteorological Research (CNRM-GAME, Toulouse, France) conducted airborne experiments in Cyprus and Ireland in March and August 2015 respectively to link ground-based and satellite observations. Multiple RPAS (remotely piloted aircraft systems) were instrumented for a specific scientific focus to characterize the vertical distribution of aerosol, cloud microphysical properties, radiative fluxes, 3D wind vectors and meteorological state parameters. Flights below and within clouds were coordinated with satellite overpasses to perform 'top-down' closure of cloud micro-physical properties. Measurements of cloud condensation nuclei spectra at the ground-based site have been used to determine cloud microphyical properties using wind vectors and meteorological parameters measured by the RPAS at cloud base. These derived cloud properties have been validated by in-situ RPAS measurements in the cloud and compared to those derived by the Suomi-NPP satellite. In addition, RPAS profiles in Cyprus observed the layers of dust originating from the Arabian Peninsula and the Sahara Desert. These profiles generally show a well-mixed boundary layer and compare well with ground-based LIDAR observations.

ROSAS: a robotic station for atmosphere and surface characterization dedicated to on-orbit calibration

NASA Astrophysics Data System (ADS)

Meygret, Aimé; Santer, Richard P.; Berthelot, Béatrice

2011-10-01

La Crau test site is used by CNES since 1987 for vicarious calibration of SPOT cameras. The former calibration activities were conducted during field campaigns devoted to the characterization of the atmosphere and the site reflectances. Since 1997, au automatic photometric station (ROSAS) was set up on the site on a 10m height pole. This station measures at different wavelengths, the solar extinction and the sky radiances to fully characterize the optical properties of the atmosphere. It also measures the upwelling radiance over the ground to fully characterize the surface reflectance properties. The photometer samples the spectrum from 380nm to 1600nm with 9 narrow bands. Every non cloudy days the photometer automatically and sequentially performs its measurements. Data are transmitted by GSM (Global System for Mobile communications) to CNES and processed. The photometer is calibrated in situ over the sun for irradiance and cross-band calibration, and over the Rayleigh scattering for the short wavelengths radiance calibration. The data are processed by an operational software which calibrates the photometer, estimates the atmosphere properties, computes the bidirectional reflectance distribution function of the site, then simulates the top of atmosphere radiance seen by any sensor over-passing the site and calibrates it. This paper describes the instrument, its measurement protocol and its calibration principle. Calibration results are discussed and compared to laboratory calibration. It details the surface reflectance characterization and presents SPOT4 calibration results deduced from the estimated TOA radiance. The results are compared to the official calibration.

The Potential Impact of Satellite-Retrieved Cloud Parameters on Ground-Level PM2.5 Mass and Composition

PubMed Central

Chang, Howard H.; Wang, Yujie; Hu, Xuefei; Lyapustin, Alexei

2017-01-01

Satellite-retrieved aerosol optical properties have been extensively used to estimate ground-level fine particulate matter (PM2.5) concentrations in support of air pollution health effects research and air quality assessment at the urban to global scales. However, a large proportion, ~70%, of satellite observations of aerosols are missing as a result of cloud-cover, surface brightness, and snow-cover. The resulting PM2.5 estimates could therefore be biased due to this non-random data missingness. Cloud-cover in particular has the potential to impact ground-level PM2.5 concentrations through complex chemical and physical processes. We developed a series of statistical models using the Multi-Angle Implementation of Atmospheric Correction (MAIAC) aerosol product at 1 km resolution with information from the MODIS cloud product and meteorological information to investigate the extent to which cloud parameters and associated meteorological conditions impact ground-level aerosols at two urban sites in the US: Atlanta and San Francisco. We find that changes in temperature, wind speed, relative humidity, planetary boundary layer height, convective available potential energy, precipitation, cloud effective radius, cloud optical depth, and cloud emissivity are associated with changes in PM2.5 concentration and composition, and the changes differ by overpass time and cloud phase as well as between the San Francisco and Atlanta sites. A case-study at the San Francisco site confirmed that accounting for cloud-cover and associated meteorological conditions could substantially alter the spatial distribution of monthly ground-level PM2.5 concentrations. PMID:29057838

Monsoon Convection during the South China Sea Monsoon Experiment Observed from Shipboard Radar and the TRMM Satellite

NASA Technical Reports Server (NTRS)

Rickenbach, Tom; Cifelli, Rob; Halverson, Jeff; Kucera, Paul; Atkinson, Lester; Fisher, Brad; Gerlach, John; Harris, Kathy; Kaufman, Cristina; Liu, Ching-Hwang;

Space-based estimation of the solar UV-B doses for psoriasis heliotherapy in Poland using OMI data for the period 2005-2011.

PubMed

Krzyścin, J W; Jarosławski, J; Rajewska-Więch, B; Sobolewski, P S; Narbutt, J; Lesiak, A; Pawlaczyk, M; Janouch, M

2012-12-05

A UV model is proposed to reconstruct the biologically weighted doses at the ground-level, erythemal, vitamin D(3), and antipsoriatic effective doses, based on the space data from the Ozone Monitoring Instrument on board of NASA EOS Aura spacecraft for the period 2005-2011. The model is training using the results of spectral UV measurements carried out at Belsk, Poland. The model outcome is verified using the UV spectra measured at Hradec Kralove, Czech Republic. The model uncertainty is almost the same for all examined action spectra and comparable to that found in earlier studies on differences between the satellite overpasses and ground-based erythemal data. Antipsoriatic doses, taken during 2h exposure periods near local noon, are reconstructed for selected sites in Poland to find if heliotherapy would be an alternative to standard treatment of psoriasis by tube irradiation in medical cabinets. Mountain-resort in the southern Poland, Zakopane, and rural-site in Central Poland, Belsk, are among the best location of potential heliotherapy centers in Poland for late spring/summer season. Łeba, resort on the Baltic Sea coast, is a potential heliotherapy center in June and July. The methodology to disclose possible heliotherapy periods over the territory of Poland could be extended to any region. It would help to prepare an optimal schedule of antipsoriatic heliotherapy that accounts for local weather conditions and medical standards of using UV cabinets. Copyright © 2012 Elsevier B.V. All rights reserved.

CALIOP near-real-time backscatter products compared to EARLINET data

NASA Astrophysics Data System (ADS)

Grigas, T.; Hervo, M.; Gimmestad, G.; Forrister, H.; Schneider, P.; Preißler, J.; Tarrason, L.; O'Dowd, C.

2015-03-01

The expedited near-real-time Level 1.5 Cloud-Aerosol Lidar (Light Detection and Ranging) with Orthogonal Polarization (CALIOP) products were evaluated against data from the ground-based European Aerosol Research Lidar Network (EARLINET). Over a period of three years, lidar data from 48 CALIOP overpasses with ground tracks within a 100 km distance from an operating EARLINET station were deemed suitable for analysis and they included a valid aerosol classification type (e.g. dust, polluted dust, clean marine, clean continental, polluted continental, mixed and/or smoke/biomass burning). For the complete dataset comprising both PBL and FT data, the correlation coefficient was 0.86, and when separated into separate layers, the PBL and FT correlation coefficients were 0.6 and 0.85 respectively. The presence of FT layers with high attenuated backscatter led to poor agreement in PBL backscatter profiles between the CALIOP and EARLINET measurements and prompted a further analysis filtering out such cases. However, the correlation coefficient value for the complete dataset decreased marginally from 0.86 to 0.84 while the PBL coefficient increased from 0.6 up to 0.65 and the FT coefficient also decreased from 0.85 to 0.79. For specific aerosol types, the correlation coefficient between CALIOP backscatter profiles and ground-based lidar data ranged from 0.37 for polluted continental aerosol in the planetary boundary layer (PBL) to 0.57 for dust in the free troposphere (FT). The results suggest different levels of agreement based on the location of the dominant aerosol layer and the aerosol type.

Improving Nocturnal Fire Detection with the VIIRS Day-Night Band

NASA Technical Reports Server (NTRS)

Polivka, Thomas N.; Wang, Jun; Ellison, Luke T.; Hyer, Edward J.; Ichoku, Charles M.

2016-01-01

Building on existing techniques for satellite remote sensing of fires, this paper takes advantage of the day-night band (DNB) aboard the Visible Infrared Imaging Radiometer Suite (VIIRS) to develop the Firelight Detection Algorithm (FILDA), which characterizes fire pixels based on both visible-light and infrared (IR) signatures at night. By adjusting fire pixel selection criteria to include visible-light signatures, FILDA allows for significantly improved detection of pixels with smaller and/or cooler subpixel hotspots than the operational Interface Data Processing System (IDPS) algorithm. VIIRS scenes with near-coincident Advanced Spaceborne Thermal Emission and Reflection (ASTER) overpasses are examined after applying the operational VIIRS fire product algorithm and including a modified "candidate fire pixel selection" approach from FILDA that lowers the 4-µm brightness temperature (BT) threshold but includes a minimum DNB radiance. FILDA is shown to be effective in detecting gas flares and characterizing fire lines during large forest fires (such as the Rim Fire in California and High Park fire in Colorado). Compared with the operational VIIRS fire algorithm for the study period, FILDA shows a large increase (up to 90%) in the number of detected fire pixels that can be verified with the finer resolution ASTER data (90 m). Part (30%) of this increase is likely due to a combined use of DNB and lower 4-µm BT thresholds for fire detection in FILDA. Although further studies are needed, quantitative use of the DNB to improve fire detection could lead to reduced response times to wildfires and better estimate of fire characteristics (smoldering and flaming) at night.

A review of the Texas, USA San Jacinto Superfund site and the deposition of polychlorinated dibenzo-p-dioxins and dibenzofurans in the San Jacinto River and Houston Ship Channel.

PubMed

Iyer, Rupa; Aggarwal, Juhi; Iken, Brian

2016-12-01

The San Jacinto River (SJR) waste pits that lie just under the 1-10 overpass in eastern Harris County east of Houston, Texas, USA, were created in the 1960s as dumping grounds for paper mill waste. The deposition of this waste led to accumulation of highly toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCCDDs/PCDFs) over the course of several decades. After abandonment, the waste material eventually became submerged under the waters of the SJR, resulting in widespread environmental contamination that currently constitutes a significant health concern for eastern Harris County communities. The original waste pits were rediscovered in 2005, and the San Jacinto waste site is now a designated EPA superfund site. The objective of this review then is to discuss the history and current state of containment around the San Jacinto waste pits and analyze spatial and temporal trends in the PCDD/PCDF deposition through the SJR system from the data available. We will discuss the current exposure and health risks represented by the Superfund site and the SJR system itself, as well as the discovery of liver, kidney, brain (glioma), and retinoblastoma cancer clusters in eastern Harris County across multiple census tracts that border the Superfund site. We will also cover the two primary management options, containment versus removal of the waste from the Superfund and provide recommendations for increased monitoring of existing concentrations of polychlorinated waste in the SJR and its nearby associated communities.

Vertical microphysical profiles of convective clouds as a tool for obtaining aerosol cloud-mediated climate forcings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosenfeld, Daniel

Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which ismore » the same as CCN(S). Developing and validating this methodology was possible thanks to the ASR/ARM measurements of CCN and vertical updraft profiles. Validation against ground-based CCN instruments at the ARM sites in Oklahoma, Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25º restricts the satellite coverage to ~25% of the world area in a single day. This methodology will likely allow overcoming the challenge of quantifying the aerosol indirect effect and facilitate a substantial reduction of the uncertainty in anthropogenic climate forcing.« less

Using AVIRIS for in-flight calibration of the spectral shifts of SPOT-HRV and of AVHRR?

NASA Technical Reports Server (NTRS)

Willart-Soufflet, Veronique; Santer, Richard

1993-01-01

The response of a satellite sensor varies during its lifetime; internal calibration devices can be used to follow the sensor degradation or in-flight calibrations are conducted from estimates of the radiance at satellite level for well predictable situations. Changes in gain are evaluated assuming that the spectral response of the sensor is stable with time; i.e., that the filter response as well as the optics or the electronics are not modified since the prelaunch determinations. Nevertheless, there is some evidence that the SPOT interferometer filters are affected by outgassing effects during the launch. Tests in vacuum chambers indicated a narrowing of the filters with a shift of the upper side towards the blue of about 10 nm which is more over consistant with the loss of gain observed during the launch. Also, during the lifetime of SPOT, the relationship between the loss of sensitivity and the filter bandwidth may correspond to this effect. On the other hand, the inconsistancy of the NOAA7 calibration between two methods (desert and ocean) having a different spectral sensitivity may indicate a spectral problem with a shift of the central wavelength of -20 nm. The basic idea here is to take advantage of the good spectral definition of AVIRIS to monitor these potential spectral degradations with an experimental opportunity provided by a field campaign held in La Crau (S.E. of France) in June 1991 which associated ground-based measurements and AVIRIS, SPOT2, NOAA-11 overpasses over both the calibration site of La Crau and an agricultural area.

Comparison of Ground- and Space-based Radar Observations with Disdrometer Measurements During the PECAN Field Campaign

NASA Astrophysics Data System (ADS)

Torres, A. D.; Rasmussen, K. L.; Bodine, D. J.; Dougherty, E.

2015-12-01

Plains Elevated Convection At Night (PECAN) was a large field campaign that studied nocturnal mesoscale convective systems (MCSs), convective initiation, bores, and low-level jets across the central plains in the United States. MCSs are responsible for over half of the warm-season precipitation across the central U.S. plains. The rainfall from deep convection of these systems over land have been observed to be underestimated by satellite radar rainfall-retrieval algorithms by as much as 40 percent. These algorithms have a strong dependence on the generally unmeasured rain drop-size distribution (DSD). During the campaign, our group measured rainfall DSDs, precipitation fall velocities, and total precipitation in the convective and stratiform regions of MCSs using Ott Parsivel optical laser disdrometers. The disdrometers were co-located with mobile pod units that measured temperature, wind, and relative humidity for quality control purposes. Data from the operational NEXRAD radar in LaCrosse, Wisconsin and space-based radar measurements from a Global Precipitation Measurement satellite overpass on July 13, 2015 were used for the analysis. The focus of this study is to compare DSD measurements from the disdrometers to radars in an effort to reduce errors in existing rainfall-retrieval algorithms. The error analysis consists of substituting measured DSDs into existing quantitative precipitation estimation techniques (e.g. Z-R relationships and dual-polarization rain estimates) and comparing these estimates to ground measurements of total precipitation. The results from this study will improve climatological estimates of total precipitation in continental convection that are used in hydrological studies, climate models, and other applications.

Characterization of Dust Properties at the Source Region During ACE-Asia

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee; Lau, William (Technical Monitor)

2001-01-01

ACE (Aerosol Characterization Experiment)-Asia is designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally-occurring aerosols, which often exist in high concentrations over eastern Asia and along the rim of the western Pacific. The phase-I of ACE-Asia was conducted from March-May 2001 in the vicinity of the Gobi desert, east coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian dust is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of dust aerosol radiative flux in addition to measurements of loading and optical thickness. At the time of the Terra/MODIS overpass, these ground-based observations can provide valuable data to compare with MODIS retrievals over land. Preliminary results will be presented and discussed their implications in regional climatic effects.

Comparison between POES energetic electron precipitation observations and riometer absorptions: Implications for determining true precipitation fluxes

NASA Astrophysics Data System (ADS)

Rodger, Craig J.; Kavanagh, Andrew J.; Clilverd, Mark A.; Marple, Steve R.

2013-12-01

electron precipitation (EEP) impacts the chemistry of the middle atmosphere with growing evidence of coupling to surface temperatures at high latitudes. To better understand this link, it is essential to have realistic observations to properly characterize precipitation and which can be incorporated into chemistry-climate models. The Polar-orbiting Operational Environmental Satellite (POES) detectors measure precipitating particles but only integral fluxes and only in a fraction of the bounce loss cone. Ground-based riometers respond to precipitation from the whole bounce loss cone; they measure the cosmic radio noise absorption (CNA), a qualitative proxy with scant direct information on the energy flux of EEP. POES observations should have a direct relationship with ΔCNA and comparing the two will clarify their utility in studies of atmospheric change. We determined ionospheric changes produced by the EEP measured by the POES spacecraft in ~250 overpasses of an imaging riometer in northern Finland. The ΔCNA modeled from the POES data is 10-15 times less than the observed ΔCNA when the >30 keV flux is reported as <106 cm-2 s-1 sr-1. Above this level, there is relatively good agreement between the space-based and ground-based measurements. The discrepancy occurs mostly during periods of low geomagnetic activity, and we contend that weak diffusion is dominating the pitch angle scattering into the bounce loss cone at these times. A correction to the calculation using measurements of the trapped flux considerably reduces the discrepancy and provides further support to our hypothesis that weak diffusion leads to underestimates of the EEP.

Total ozone changes over Eurasia since 1973 based on reevaluated filter ozonometer data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bojkov, R.D.; Fioletov, V.E.; Shalamjansky, A.M.

1994-11-01

Since the early 1960s, on the vast territory of the former USSR, 45 stations have been in continuous operation, utilizing the broadband filter M-83 ozonometer. The quality of the ozone data during the first decade was unsatisfactory. After 1972 an improved version of the ozonometer was introduced together with improved quality control practices, including methodology of observations. The more reliable data of 1973 through March 1994 have been rigorously reexamined by applying variability analysis, comparison with lower-stratosphere temperatures and/or nearby Dobson stations, and overpassing Total Ozone Mapping Spectrometer (TOMS) for identifying concurrence or discrepancies. These control procedures together with themore » information on instrument relocation and calibrations made it possible to reevaluate the record of all 45 stations. The accuracy of the improved ozonometer data is about 3% for direct Sun measurements and approximately 5% for zenith sky observations; although not so good as that of the Dobson, in the long run it provides consistent ozone data sets. This data set is now made available to the World Ozone Data Center (WO3DC), Toronto. Thus for the first time, based on a 21-year long record, information is deduced on the differences in the ozone annual cycle between Eastern Siberia and the European part, on the strong appearance of quasi-biennial oscillation (QBO) signals especially pronounced as ozone deficiency during the western phase of the QBO, on the ozone variability, and on the long-term changes over the huge territory from Central Europe to the Far East.« less

The influences of land use and land cover on climate; an analysis of the Washington-Baltimore area that couples remote sensing with numerical simulation

USGS Publications Warehouse

Pease, R.W.; Jenner, C.B.; Lewis, J.E.

1980-01-01

The Sun drives the atmospheric heat engine by warming the terrestrial surface which in turn warms the atmosphere above. Climate, therefore, is significantly controlled by complex interaction of energy flows near and at the terrestrial surface. When man alters this delicate energy balance by his use of the land, he may alter his climatic environment as well. Land use climatology has emerged as a discipline in which these energy interactions are studied; first, by viewing the spatial distributions of their surface manifestations, and second, by analyzing the energy exchange processes involved. Two new tools for accomplishing this study are presented: one that can interpret surface energy exchange processes from space, and another that can simulate the complex of energy transfers by a numerical simulation model. Use of a satellite-borne multispectral scanner as an imaging radiometer was made feasible by devising a gray-window model that corrects measurements made in space for the effects of the atmosphere in the optical path. The simulation model is a combination of mathematical models of energy transfer processes at or near the surface. Integration of these two analytical approaches was applied to the Washington-Baltimore area to coincide with the August 5, 1973, Skylab 3 overpass which provided data for constructing maps of the energy characteristics of the Earth's surface. The use of the two techniques provides insights into the relationship of climate to land use and land cover and in predicting alterations of climate that may result from alterations of the land surface.

Soil moisture variability across different scales in an Indian watershed for satellite soil moisture product validation

NASA Astrophysics Data System (ADS)

Singh, Gurjeet; Panda, Rabindra K.; Mohanty, Binayak P.; Jana, Raghavendra B.

2016-05-01

Strategic ground-based sampling of soil moisture across multiple scales is necessary to validate remotely sensed quantities such as NASA's Soil Moisture Active Passive (SMAP) product. In the present study, in-situ soil moisture data were collected at two nested scale extents (0.5 km and 3 km) to understand the trend of soil moisture variability across these scales. This ground-based soil moisture sampling was conducted in the 500 km2 Rana watershed situated in eastern India. The study area is characterized as sub-humid, sub-tropical climate with average annual rainfall of about 1456 mm. Three 3x3 km square grids were sampled intensively once a day at 49 locations each, at a spacing of 0.5 km. These intensive sampling locations were selected on the basis of different topography, soil properties and vegetation characteristics. In addition, measurements were also made at 9 locations around each intensive sampling grid at 3 km spacing to cover a 9x9 km square grid. Intensive fine scale soil moisture sampling as well as coarser scale samplings were made using both impedance probes and gravimetric analyses in the study watershed. The ground-based soil moisture samplings were conducted during the day, concurrent with the SMAP descending overpass. Analysis of soil moisture spatial variability in terms of areal mean soil moisture and the statistics of higher-order moments, i.e., the standard deviation, and the coefficient of variation are presented. Results showed that the standard deviation and coefficient of variation of measured soil moisture decreased with extent scale by increasing mean soil moisture.

Ground based remote sensing retrievals and observations of snowfall in the Telemark region of Norway

NASA Astrophysics Data System (ADS)

Pettersen, C.; L'Ecuyer, T. S.; Wood, N.; Cooper, S.; Wolff, M. A.; Petersen, W. A.; Bliven, L. F.; Tushaus, S. A.

2017-12-01

Snowfall can be broadly categorized into deep and shallow events, based on the vertical extent of the frozen precipitation in the column. The two categories are driven by different thermodynamic and physical mechanisms in the atmosphere and surface. Though satellites can observe and recognize these patterns in snowfall, these measurements are limited - particularly in cases of shallow and light precipitation and over complex terrain. By enhancing satellite measurements with ground-based instrumentation, whether with limited-term field campaigns or long-term strategic sites, we can further our understanding and assumptions about different snowfall modes. We present data collected in a recently deployed ground suite of instruments based in Norway. The Meteorological Institute of Norway has a snow measurement suite in Haukeliseter located in the orographically complex Telemark region. This suite consists of several snow accumulation instruments as well as meteorological data (temperature, dew point, wind speeds and directions). A joint project between University of Wisconsin and University of Utah augmented this suite with a 24 GHz radar MicroRain Radar (MRR), a NASA Particle Imaging Package (PIP), and a Multi-Angle Snowflake Camera (MASC). Preliminary data from this campaign are presented along with coincident overpasses from the GPM satellite. We compare the ground-based and spaceborne remotely sensed estimates of snowfall with snow gauge observations from the Haukeliseter site. Finally, we discuss how particle size distribution and fall velocity observations from the PIP and MASC can be used to improve remotely-sensed snowfall retrievals as a function of environmental conditions at Haukeliseter.

A diagnostic Study of a High Impact Weather Episode in the Western Mediterranean Region: IOP8 a HyMeX case

NASA Astrophysics Data System (ADS)

Khodayar, Samiro; Kalthoff, Norbert; Raff, Fritz

2013-04-01

Fall season heavy rainfall in the western Mediterranean region is one of the most threatening phenomena in the area. Devastating flash floods occur every year somewhere in eastern Spain resulting in a large amount of property losses, destruction of infrastructures, enormous agricultural losses and human fatalities. The forecast of the underlying HIW is a subject of special concern for local meteorologist because of its catastrophic nature. Within the framework of HyMeX (Hydrological cycle in the Mediterranean eXperiment) a HIW (High Impact Weather) event took place on the south and eastern part of the Spanish coast, particularly in Andalusia, Murcia, Valencia, Catalonia and less pronouncedly in the Balearic Islands, moving afterwards towards France southern coast. During this event casualties and important economic damage were registered. The amounts of precipitation locally overpassed 200 mm in 24 hours and a tornado occurred in Gandia (Valencia). The main objective of this work is to provide a comprehensive description of the physical atmospheric processes giving rise to the intense precipitation in this event and its movement along the Spanish coast. High-resolution COSMO-CLM model simulations supported by the analysis of observational data sets will be presented. The model simulations and observational data sets, such as a dense network of global positioning systems (GPS), raingauges, surface measurements and radiosoundings are analyzed to document in detail the evolution of the warm and wet air masses which fed the high precipitation event (HPE) systems, as well as the low-level convergence to which the main convective systems were associated.

Assessment of ecological passages along road networks within the Mediterranean forest using GIS-based multi criteria evaluation approach.

PubMed

Gülci, Sercan; Akay, Abdullah Emin

2015-12-01

Major roads cause barrier effect and fragmentation on wildlife habitats that are suitable places for feeding, mating, socializing, and hiding. Due to wildlife collisions (Wc), human-wildlife conflicts result in lost lives and loss of biodiversity. Geographical information system (GIS)-based multi criteria evaluation (MCE) methods have been successfully used in short-term planning of road networks considering wild animals. Recently, wildlife passages have been effectively utilized as road engineering structures provide quick and certain solutions for traffic safety and wildlife conservation problems. GIS-based MCE methods provide decision makers with optimum location for ecological passages based on habitat suitability models (HSMs) that classify the areas based on ecological requirements of target species. In this study, ecological passages along Motorway 52 within forested areas in Mediterranean city of Osmaniye in Turkey were evaluated. Firstly, HSM coupled with nine eco-geographic decision variables were developed based on ecological requirements of roe deer (Capreolus capreolus) that were chosen as target species. Then specified decision variables were evaluated using GIS-based weighted linear combination (WLC) method to estimate movement corridors and mitigation points along the motorway. In the solution process, two linkage nodes were evaluated for eco-passages which were determined based on the least-cost movement corridor intersecting with the motorway. One of the passages was identified as a natural wildlife overpass while the other was suggested as underpass construction. The results indicated that computer-based models provide accurate and quick solutions for positioning ecological passages to reduce environmental effects of road networks on wild animals.

Airborne MAX-DOAS Measurements Over California: Testing the NASA OMI Tropospheric NO2 Product

NASA Technical Reports Server (NTRS)

Oetjen, Hilke; Baidar, Sunil; Krotkov, Nickolay A.; Lamsal, Lok N.; Lechner, Michael; Volkamer, Rainer

2013-01-01

Airborne Multi-AXis Differential Optical Absorption Spectroscopy (AMAX-DOAS) measurements of NO2 tropospheric vertical columns were performed over California for two months in summer 2010. The observations are compared to the NASA Ozone Monitoring Instrument (OMI) tropospheric vertical columns (data product v2.1) in two ways: (1) Median data were compared for the whole time period for selected boxes, and the agreement was found to be fair (R = 0.97, slope = 1.4 +/- 0.1, N= 10). (2) A comparison was performed on the mean of coincident AMAX-DOAS measurements within the area of the corresponding OMI pixels with the tropospheric NASA OMI NO2 assigned to that pixel. The effects of different data filters were assessed. Excellent agreement and a strong correlation (R = 0.85, slope = 1.05 +/- 0.09, N= 56) was found for (2) when the data were filtered to eliminate large pixels near the edge of the OMI orbit, the cloud radiance fraction was<50%, the OMI overpass occurred within 2 h of the AMAX-DOAS measurements, the flight altitude was>2 km, and a representative sample of the footprint was taken by the AMAX-DOAS instrument. The AMAX-DOAS and OMI data sets both show a reduction of NO2 tropospheric columns on weekends by 38 +/- 24% and 33 +/- 11%, respectively. The assumptions in the tropospheric satellite air mass factor simulations were tested using independent measurements of surface albedo, aerosol extinction, and NO2 profiles for Los Angeles for July 2010 indicating an uncertainty of 12%.

Nearshore Satellite Data as Relative Indicators of Intertidal Organism Physiological Stress

NASA Astrophysics Data System (ADS)

Matzelle, A.; Helmuth, B.; Lakshmi, V.

2011-12-01

The physiological performance of intertidal and shallow subtidal invertebrates and algae is significantly affected by water temperature, and so the ability to measure and model onshore water temperatures is critical for ecological and biogeographic studies. Because of the localized influences of processes such as upwelling, mixing, and surface heating from solar radiation, nearshore water temperatures can differ from those measured directly offshore by buoys and satellites. It remains an open question what the magnitude of the differences in these temperatures are, and whether "large pixel" measurements can serve as an effective proxy for onshore processes, particularly when extrapolating from laboratory physiological studies to field conditions. We compared 9 years of nearshore (~10km) MODIS (Terra and Aqua overpasses) SST data against in situ measurements of water temperature conducted at two intertidal sites in central Oregon- Boiler Bay and Strawberry Hill. We collapsed data into increasingly longer temporal averages to address the correlation and absolute differences between onshore and nearshore temperatures over daily, weekly and monthly timescales. Results indicate that nearshore SST is a reasonable proxy for onshore water temperature, and that the strength of the correlation increases with decreasing temporal resolution. Correlations between differences in maxima are highest, followed by average and minima, and were lower at a site with regular upwelling. While average differences ranged from ~0.199-1.353°C, absolute differences across time scales were ~0.446-6.906°C, and were highest for cold temperatures. The results suggest that, at least at these two sites, SST can be used as a relative proxy for general trends only, especially over longer time scales.

The Potential Impact of Satellite-Retrieved Cloud Parameters on Ground-Level PM2.5 Mass and Composition

NASA Technical Reports Server (NTRS)

Belle, Jessica H.; Chang, Howard H.; Wang, Yujie; Hu, Xuefei; Lyapustin, Alexei; Liu, Yang

2017-01-01

Satellite-retrieved aerosol optical properties have been extensively used to estimate ground-level fine particulate matter (PM2.5) concentrations in support of air pollution health effects research and air quality assessment at the urban to global scales. However, a large proportion, approximately 70%, of satellite observations of aerosols are missing as a result of cloud-cover, surface brightness, and snow-cover. The resulting PM2.5 estimates could therefore be biased due to this non-random data missingness. Cloud-cover in particular has the potential to impact ground-level PM2.5 concentrations through complex chemical and physical processes. We developed a series of statistical models using the Multi-Angle Implementation of Atmospheric Correction (MAIAC) aerosol product at 1 km resolution with information from the MODIS cloud product and meteorological information to investigate the extent to which cloud parameters and associated meteorological conditions impact ground-level aerosols at two urban sites in the US: Atlanta and San Francisco. We find that changes in temperature, wind speed, relative humidity, planetary boundary layer height, convective available potential energy, precipitation, cloud effective radius, cloud optical depth, and cloud emissivity are associated with changes in PM2.5 concentration and composition, and the changes differ by overpass time and cloud phase as well as between the San Francisco and Atlanta sites. A case-study at the San Francisco site confirmed that accounting for cloud-cover and associated meteorological conditions could substantially alter the spatial distribution of monthly ground-level PM2.5 concentrations.

Aqua and Terra MODIS RSB Calibration Comparison Using BRDF Modeled Reflectance

NASA Technical Reports Server (NTRS)

Chang, Tiejun; Xiong, Xiaoxiong; Angal, Amit; Wu, Aisheng; Geng, Xu

2017-01-01

The inter-comparison of MODIS reflective solar bands onboard Aqua and Terra is very important for assessment of each instrument's calibration. One of the limitations is the lack of simultaneous nadir overpasses. Their measurements over a selected Earth view target have significant differences in solar and view angles, which magnify the effects of atmospheric scattering and Bidirectional Reflectance Distribution Function (BRDF). In this work, an intercomparison technique is formulated after correction for site's BRDF and atmospheric effects. The reflectance measurements over Libya desert sites 1, 2, and 4 from both the Aqua and Terra MODIS are regressed to a BRDF model with an adjustable coefficient accounting for calibration difference. The ratio between Aqua and Terra reflectance measurements are derived for bands 1 to 9 and the results from different sites show good agreement. For year 2003, the ratios are in the range of 0.985 to1.010 for band 1 to 9. Band 3 shows the lowest ratio 0.985 and band 1 shows the highest ratio 1.010. For the year 2014, the ratio ranges from approximately 0.983 for bands 2 and 1.012 for band 8. The BRDF corrected reflectance for the two instruments are also derived for every year from 2003 to 2014 for stability assessment. Bands 1 and 2 show greater than 1 differences between the two instruments. Aqua bands 1 and 2 show downward trends while Terra bands 1 and 2 show upward trends. Bands 8 and 9 of both Aqua and Terra show large variations of reflectance measurement over time.

The TROPOMI surface UV algorithm

NASA Astrophysics Data System (ADS)

Lindfors, Anders V.; Kujanpää, Jukka; Kalakoski, Niilo; Heikkilä, Anu; Lakkala, Kaisa; Mielonen, Tero; Sneep, Maarten; Krotkov, Nickolay A.; Arola, Antti; Tamminen, Johanna

2018-02-01

The TROPOspheric Monitoring Instrument (TROPOMI) is the only payload of the Sentinel-5 Precursor (S5P), which is a polar-orbiting satellite mission of the European Space Agency (ESA). TROPOMI is a nadir-viewing spectrometer measuring in the ultraviolet, visible, near-infrared, and the shortwave infrared that provides near-global daily coverage. Among other things, TROPOMI measurements will be used for calculating the UV radiation reaching the Earth's surface. Thus, the TROPOMI surface UV product will contribute to the monitoring of UV radiation by providing daily information on the prevailing UV conditions over the globe. The TROPOMI UV algorithm builds on the heritage of the Ozone Monitoring Instrument (OMI) and the Satellite Application Facility for Atmospheric Composition and UV Radiation (AC SAF) algorithms. This paper provides a description of the algorithm that will be used for estimating surface UV radiation from TROPOMI observations. The TROPOMI surface UV product includes the following UV quantities: the UV irradiance at 305, 310, 324, and 380 nm; the erythemally weighted UV; and the vitamin-D weighted UV. Each of these are available as (i) daily dose or daily accumulated irradiance, (ii) overpass dose rate or irradiance, and (iii) local noon dose rate or irradiance. In addition, all quantities are available corresponding to actual cloud conditions and as clear-sky values, which otherwise correspond to the same conditions but assume a cloud-free atmosphere. This yields 36 UV parameters altogether. The TROPOMI UV algorithm has been tested using input based on OMI and the Global Ozone Monitoring Experiment-2 (GOME-2) satellite measurements. These preliminary results indicate that the algorithm is functioning according to expectations.

The Potential Impact of Satellite-Retrieved Cloud Parameters on Ground-Level PM2.5 Mass and Composition.

PubMed

Belle, Jessica H; Chang, Howard H; Wang, Yujie; Hu, Xuefei; Lyapustin, Alexei; Liu, Yang

2017-10-18

Satellite-retrieved aerosol optical properties have been extensively used to estimate ground-level fine particulate matter (PM 2.5 ) concentrations in support of air pollution health effects research and air quality assessment at the urban to global scales. However, a large proportion, ~70%, of satellite observations of aerosols are missing as a result of cloud-cover, surface brightness, and snow-cover. The resulting PM 2.5 estimates could therefore be biased due to this non-random data missingness. Cloud-cover in particular has the potential to impact ground-level PM 2.5 concentrations through complex chemical and physical processes. We developed a series of statistical models using the Multi-Angle Implementation of Atmospheric Correction (MAIAC) aerosol product at 1 km resolution with information from the MODIS cloud product and meteorological information to investigate the extent to which cloud parameters and associated meteorological conditions impact ground-level aerosols at two urban sites in the US: Atlanta and San Francisco. We find that changes in temperature, wind speed, relative humidity, planetary boundary layer height, convective available potential energy, precipitation, cloud effective radius, cloud optical depth, and cloud emissivity are associated with changes in PM 2.5 concentration and composition, and the changes differ by overpass time and cloud phase as well as between the San Francisco and Atlanta sites. A case-study at the San Francisco site confirmed that accounting for cloud-cover and associated meteorological conditions could substantially alter the spatial distribution of monthly ground-level PM 2.5 concentrations.

Production of Arctic Sea-ice Albedo by fusion of MISR and MODIS data

NASA Astrophysics Data System (ADS)

Kharbouche, Said; Muller, Jan-Peter

2017-04-01

We have combined data from the NASA MISR and MODIS spectro-radiometers to create a cloud-free albedo dataset specifically for sea-ice. The MISR (Multi-Angular Spectro-Radiometer) instrument on board Terra satellite has a unique ability to create high-quality Bidirectional Reflectance (BRF) over a 7 minute time interval per single overpass, thanks to its 9 cameras of different view angles (±70°,±60°,±45°,±26°). However, as MISR is limited to narrow spectral bands (443nm, 555nm, 670nm, 865nm), which is not sufficient to mask cloud effectively and robustly, we have used the sea-ice mask MOD09 product (Collection 6) from MODIS (Moderate resolution Imaging Spectoradiometer) instrument, which is also on board Terra satellite and acquiring data simultaneously. Only We have created a new and consistent sea-ice (for Arctic) albedo product that is daily, from 1st March to 22nd September for each and every year between 2000 to 2016 at two spatial grids, 1km x 1km and 5km x 5km in polar stereographic projection. Their analysis is described in a separate report [1]. References [1] Muller & Kharbouche, Variation of Arctic's Sea-ice Albedo between 2000 and 2016 by fusion of MISR and MODIS data. This conference. Acknowledgements This work was supported by www.QA4ECV.eu, a project of European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 607405. We thank our colleagues at JPL and NASA LaRC for processing these data, especially Sebastian Val and Steve Protack.

North Atlantic Aerosol Properties for Radiative Impact Assessments. Derived from Column Closure Analyses in TARFOX and ACE-2

NASA Technical Reports Server (NTRS)

Russell, Philip A.; Bergstrom, Robert A.; Schmid, Beat; Livingston, John M.

2000-01-01

Aerosol effects on atmospheric radiative fluxes provide a forcing function that can change the climate in potentially significant ways. This aerosol radiative forcing is a major source of uncertainty in understanding the climate change of the past century and predicting future climate. To help reduce this uncertainty, the 1996 Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the 1997 Aerosol Characterization Experiment (ACE-2) measured the properties and radiative effects of aerosols over the Atlantic Ocean. Both experiments used remote and in situ measurements from aircraft and the surface, coordinated with overpasses by a variety of satellite radiometers. TARFOX focused on the urban-industrial haze plume flowing from the United States over the western Atlantic, whereas ACE-2 studied aerosols over the eastern Atlantic from both Europe and Africa. These aerosols often have a marked impact on satellite-measured radiances. However, accurate derivation of flux changes, or radiative forcing, from the satellite measured radiances or retrieved aerosol optical depths (AODs) remains a difficult challenge. Here we summarize key initial results from TARFOX and ACE-2, with a focus on closure analyses that yield aerosol microphysical models for use in improved assessments of flux changes. We show how one such model gives computed radiative flux sensitivities (dF/dAOD) that agree with values measured in TARFOX and preliminary values computed for the polluted marine boundary layer in ACE-2. A companion paper uses the model to compute aerosol-induced flux changes over the North Atlantic from AVHRR-derived AOD fields.

Comparison of three methods for long-term monitoring of boreal lake area using Landsat TM and ETM+ imagery

USGS Publications Warehouse

Roach, Jennifer K.; Griffith, Brad; Verbyla, David

2012-01-01

Programs to monitor lake area change are becoming increasingly important in high latitude regions, and their development often requires evaluating tradeoffs among different approaches in terms of accuracy of measurement, consistency across multiple users over long time periods, and efficiency. We compared three supervised methods for lake classification from Landsat imagery (density slicing, classification trees, and feature extraction). The accuracy of lake area and number estimates was evaluated relative to high-resolution aerial photography acquired within two days of satellite overpasses. The shortwave infrared band 5 was better at separating surface water from nonwater when used alone than when combined with other spectral bands. The simplest of the three methods, density slicing, performed best overall. The classification tree method resulted in the most omission errors (approx. 2x), feature extraction resulted in the most commission errors (approx. 4x), and density slicing had the least directional bias (approx. half of the lakes with overestimated area and half of the lakes with underestimated area). Feature extraction was the least consistent across training sets (i.e., large standard error among different training sets). Density slicing was the best of the three at classifying small lakes as evidenced by its lower optimal minimum lake size criterion of 5850 m2 compared with the other methods (8550 m2). Contrary to conventional wisdom, the use of additional spectral bands and a more sophisticated method not only required additional processing effort but also had a cost in terms of the accuracy and consistency of lake classifications.

Coordinated Ground-Based and AIM Satellite Measurements of Mesospheric and Stratospheric Waves over South America

NASA Astrophysics Data System (ADS)

Taylor, M. J.; Zhao, Y.; Pautet, P. D.; Carstens, J. N.; Pugmire, J. R.; Smith, S. M.; Liu, A. Z.; Vargas, F.; Swenson, G. R.; Randall, C. E.; Bailey, S. M.; Russell, J. M., III

2016-12-01

To date, the primary research goals of the Aeronomy of Ice in the Mesosphere (AIM) satellite have focussed on investigating the occurrence, properties and dynamics of high-latitude Polar Mesospheric Clouds (PMC). With the evolution of the AIM orbit beta angle the opportunity now exists to make measurements outside the PMC region covering mid-low and equatorial latitudes. As part of the extended AIM mission science program, the AIM platform in conjunction with auxiliary ground-based measurements will be used to better understand upper atmospheric dynamics and vertical coupling due to gravity waves. Over the next 2 years AIM will take advantage of a new imaging capability of the on-board large-field CIPS UV imager to capture new data on the characteristics and spatial extents of stratospheric gravity waves near the 50 km level and their variation with latitude and season. In this study we report on initial coordinated ground-based measurements with the Andes Lidar Observatory (ALO) at Cerro Pachon, Chile ( 30°S) and nearby El Leoncito Observatory, Argentina, high in the Andes Mountains, where regular remote-sensing measurements are made using meteor radar, mesospheric airglow imagers, temperature mappers and an Na wind-temperature lidar (on a campaign basis). First coordinated measurements were made during the winter period in June 2016. AIM daytime overpasses have been analysed to search for and characterize extensive stratospheric wave events, as well as long-lived "Mountain Waves" over South America. Subsequent night-time ground-based measurements have been used to quantify wave characteristics in the mesopause region ( 80-100 km) to investigate vertical coupling. These measurements are continuing and it is planned to extend the new AIM stratospheric gravity wave data set for similar studies from a number of well-instrumented ground sites around the world.

Forecast, Measurement, and Modeling of an Unprecedented Polar Ozone Filament Event over Mauna Loa Observatory, Hawaii

NASA Technical Reports Server (NTRS)

Tripathi, Om Prakash; Leblanc, Thierry; McDermid, I. Stuart; Lefevre, Frank; Marchand, Marion; Hauchecorne, Alain

2006-01-01

In mid-March 2005 the northern lower stratospheric polar vortex experienced a severe stretching episode, bringing a large polar filament far south of Alaska toward Hawaii. This meridional intrusion of rare extent, coinciding with the polar vortex final warming and breakdown, was followed by a zonal stretching in the wake of the easterly propagating subtropical main flow. This caused polar air to remain over Hawaii for several days before diluting into the subtropics. After being successfully forecasted to pass over Hawaii by the high-resolution potential vorticity advection model Modele Isentrope du transport Meso-echelle de l'Ozone Stratospherique par Advection (MIMOSA), the filament was observed on isentropic surfaces between 415 K and 455 K (17-20 km) by the Jet Propulsion Laboratory stratospheric ozone lidar measurements at Mauna Loa Observatory, Hawaii, between 16 and 19 March 2005. It was materialized as a thin layer of enhanced ozone peaking at 1.6 ppmv in a region where the climatological values usually average 1.0 ppmv. These values were compared to those obtained by the three dimensional Chemistry-Transport Model MIMOSA-CHIM. Agreement between lidar and model was excellent, particularly in the similar appearance of the ozone peak near 435 K (18.5 km) on 16 March, and the persistence of this layer at higher isentropic levels for the following three days. Passive ozone, also modeled by MIMOSA-CHIM, was at about 3-4 ppmv inside the filament while above Hawaii. A detailed history of the modeled chemistry inside the filament suggests that the air mass was still polar ozone- depleted when passing over Hawaii. The filament quickly separated from the main vortex after its Hawaiian overpass. It never reconnected and, in less than 10 days, dispersed entirely in the subtropics.

Development of Waypoint Planning Tool in Response to NASA Field Campaign Challenges

NASA Technical Reports Server (NTRS)

He, Matt; Hardin, Danny; Mayer, Paul; Blakeslee, Richard; Goodman, Michael

2012-01-01

Airborne real time observations are a major component of NASA 's Earth Science research and satellite ground validation studies. Multiple aircraft are involved in most NASA field campaigns. The coordination of the aircraft with satellite overpasses, other airplanes and the constantly evolving, dynamic weather conditions often determines the success of the campaign. Planning a research aircraft mission within the context of meeting the science objectives is a complex task because it requires real time situational awareness of the weather conditions that affect the aircraft track. A flight planning tools is needed to provide situational awareness information to the mission scientists, and help them plan and modify the flight tracks. Scientists at the University of Alabama ]Huntsville and the NASA Marshall Space Flight Center developed the Waypoint Planning Tool, an interactive software tool that enables scientists to develop their own flight plans (also known as waypoints) with point -and-click mouse capabilities on a digital map filled with real time raster and vector data. The development of this Waypoint Planning Tool demonstrates the significance of mission support in responding to the challenges presented during NASA field campaigns. Analysis during and after each campaign helped identify both issues and new requirements, and initiated the next wave of development. Currently the Waypoint Planning Tool has gone through three rounds of development and analysis processes. The development of this waypoint tool is directly affected by the technology advances on GIS/Mapping technologies. From the standalone Google Earth application and simple KML functionalities, to Google Earth Plugin on web platform, and to the rising open source GIS tools with New Java Script frameworks, the Waypoint Planning Tool has entered its third phase of technology advancement. Adapting new technologies for the Waypoint Planning Tool ensures its success in helping scientist reach their mission objectives.

Estimates of Lightning NOx Production Based on OMI NO2 Observations Over the Gulf of Mexico

NASA Technical Reports Server (NTRS)

Pickering, Kenneth E.; Bucsela, Eric; Allen, Dale; Ring, Allison; Holzworth, Robert; Krotkov, Nickolay

2016-01-01

We evaluate nitrogen oxide (NO(sub x) NO + NO2) production from lightning over the Gulf of Mexico region using data from the Ozone Monitoring Instrument (OMI) aboard NASAs Aura satellite along with detection efficiency-adjusted lightning data from the World Wide Lightning Location Network (WWLLN). A special algorithm was developed to retrieve the lightning NOx [(LNO(sub x)] signal from OMI. The algorithm in its general form takes the total slant column NO2 from OMI and removes the stratospheric contribution and tropospheric background and includes an air mass factor appropriate for the profile of lightning NO(sub x) to convert the slant column LNO2 to a vertical column of LNO(sub x). WWLLN flashes are totaled over a period of 3 h prior to OMI overpass, which is the time an air parcel is expected to remain in a 1 deg. x 1 deg. grid box. The analysis is conducted for grid cells containing flash counts greater than a threshold value of 3000 flashes that yields an expected LNO(sub x) signal greater than the background. Pixels with cloud radiance fraction greater than a criterion value (0.9) indicative of highly reflective clouds are used. Results for the summer seasons during 2007-2011 yield mean LNO(sub x) production of approximately 80 +/- 45 mol per flash over the region for the two analysis methods after accounting for biases and uncertainties in the estimation method. These results are consistent with literature estimates and more robust than many prior estimates due to the large number of storms considered but are sensitive to several substantial sources of uncertainty.

Observational evidence of fire-driven changes to tropical cloudiness

NASA Astrophysics Data System (ADS)

Tosca, Michael; Diner, David; Garay, Michael; Kalashnikova, Olga

2014-05-01

Anthropogenic fires in the tropics emit smoke aerosols that affect cloud dynamics, meteorology and climate (Tosca et al., 2013). We developed a new technique to observationally quantify the cloud response to biomass burning aerosols using aerosol retrievals from the Multi-angle Imaging SpectroRadiometer (MISR) and non-coincident cloud retrievals from the MODerate resolution Imaging Spectroradiometer (MODIS) from collocated morning and afternoon overpasses. The Global Fire Emissions Database, version 3 and Level 2 data from scenes acquired between 2006 and 2010 were used to quantify changes in cloud fraction from morning (10:30am local time) to afternoon (1:30pm local time) in the presence of varying fire-aerosol burdens. This temporal offset allowed for analysis of the evolution of clouds in the presence of aerosols, something that previous methods using coincident observations could not produce. We controlled for large-scale meteorological differences between scenes using reanalysis data from the ERA-interim product and matching scenes with fire smoke to those with no smoke and similar initial (morning) meteorological conditions. Elevated aerosol optical depths (AODs) reduced cloud fraction from morning to afternoon in the Southeast Asia, Central America and northern Africa burning regions. In mostly cloudy conditions, aerosols significantly reduced cloud fraction, but in clear skies, cloud fraction increased. These results support the general hypothesis of a positive feedback loop between anthropogenic burning and cloudiness in tropical regions, and are consistent with previous studies linking smoke aerosols to convective cloud reduction. Tosca, M.G., J.T. Randerson and C.S. Zender (2013), Global impact of smoke aerosols from landscape fires on climate and the Hadley circulation, Atmos. Chem. Phys., 13, 5227-5241, doi: 10.5194/acp-13-5227-2013.

A novel cross-satellite based assessment of the spatio-temporal development of a cyanobacterial harmful algal bloom

NASA Astrophysics Data System (ADS)

Page, Benjamin P.; Kumar, Abhishek; Mishra, Deepak R.

2018-04-01

As the frequency of cyanobacterial harmful algal blooms (CyanoHABs) become more common in recreational lakes and water supply reservoirs, demand for rapid detection and temporal monitoring will be imminent for effective management. The goal of this study was to demonstrate a novel and potentially operational cross-satellite based protocol for synoptic monitoring of rapidly evolving and increasingly common CyanoHABs in inland waters. The analysis involved a novel way to cross-calibrate a chlorophyll-a (Chl-a) detection model for the Landsat-8 OLI sensor from the relationship between the normalized difference chlorophyll index and the floating algal index derived from Sentinel-2A on a coinciding overpass date during the summer CyanoHAB bloom in Utah Lake. This aided in the construction of a time-series phenology of the Utah Lake CyanoHAB event. Spatio-temporal cyanobacterial density maps from both Sentinel-2A and Landsat-8 sensors revealed that the bloom started in the first week of July 2016 (July 3rd, mean cell count: 9163 cells/mL), reached peak in mid-July (July 15th, mean cell count: 108176 cells/mL), and reduced in August (August 24th, mean cell count: 9145 cells/mL). Analysis of physical and meteorological factors suggested a complex interaction between landscape processes (high surface runoff), climatic conditions (high temperature, high rainfall followed by negligible rainfall, stable wind), and water quality (low water level, high Chl-a) which created a supportive environment for triggering these blooms in Utah Lake. This cross satellite-based monitoring methods can be a great tool for regular monitoring and will reduce the budget cost for monitoring and predicting CyanoHABs in large lakes.

The 1998-2000 SHADOZ (Southern Hemisphere ADditional OZonesondes) Tropical Ozone Climatology: Ozonesonde Precision, Accuracy and Station-to-Station Variability

NASA Technical Reports Server (NTRS)

Witte, J. C.; Thompson, Anne M.; McPeters, R. D.; Oltmans, S. J.; Schmidlin, F. J.; Bhartia, P. K. (Technical Monitor)

2001-01-01

As part of the SAFARI-2000 campaign, additional launches of ozonesondes were made at Irene, South Africa and at Lusaka, Zambia. These represent campaign augmentations to the SHADOZ database described in this paper. This network of 10 southern hemisphere tropical and subtropical stations, designated the Southern Hemisphere ADditional OZonesondes (SHADOZ) project and established from operational sites, provided over 1000 profiles from ozonesondes and radiosondes during the period 1998-2000. (Since that time, two more stations, one in southern Africa, have joined SHADOZ). Archived data are available at: http://code9l6.gsfc.nasa.gov/Data-services/shadoz>. Uncertainties and accuracies within the SHADOZ ozone data set are evaluated by analyzing: (1) imprecisions in stratospheric ozone profiles and in methods of extrapolating ozone above balloon burst; (2) comparisons of column-integrated total ozone from sondes with total ozone from the Earth-Probe/TOMS (Total Ozone Mapping Spectrometer) satellite and ground-based instruments; (3) possible biases from station-to-station due to variations in ozonesonde characteristics. The key results are: (1) Ozonesonde precision is 5%; (2) Integrated total ozone column amounts from the sondes are in good agreement (2-10%) with independent measurements from ground-based instruments at five SHADOZ sites and with overpass measurements from the TOMS satellite (version 7 data). (3) Systematic variations in TOMS-sonde offsets and in groundbased-sonde offsets from station to station reflect biases in sonde technique as well as in satellite retrieval. Discrepancies are present in both stratospheric and tropospheric ozone. (4) There is evidence for a zonal wave-one pattern in total and tropospheric ozone, but not in stratospheric ozone.

Airborne Sun photometry and Closure Studies in SAFARI-2000 Dry Season Campaign

NASA Technical Reports Server (NTRS)

Schmid, B.; Russell, P. B.; Pilewskie, P.; Redemann, J.; Livingston, J. M.; Hobbs, P. V.; Welton, E. J.; Campbell, J.; Holben, B. N.; McGill, M.;

Data Assimilation on a Quantum Annealing Computer: Feasibility and Scalability

NASA Astrophysics Data System (ADS)

Nearing, G. S.; Halem, M.; Chapman, D. R.; Pelissier, C. S.

2014-12-01

Data assimilation is one of the ubiquitous and computationally hard problems in the Earth Sciences. In particular, ensemble-based methods require a large number of model evaluations to estimate the prior probability density over system states, and variational methods require adjoint calculations and iteration to locate the maximum a posteriori solution in the presence of nonlinear models and observation operators. Quantum annealing computers (QAC) like the new D-Wave housed at the NASA Ames Research Center can be used for optimization and sampling, and therefore offers a new possibility for efficiently solving hard data assimilation problems. Coding on the QAC is not straightforward: a problem must be posed as a Quadratic Unconstrained Binary Optimization (QUBO) and mapped to a spherical Chimera graph. We have developed a method for compiling nonlinear 4D-Var problems on the D-Wave that consists of five steps: Emulating the nonlinear model and/or observation function using radial basis functions (RBF) or Chebyshev polynomials. Truncating a Taylor series around each RBF kernel. Reducing the Taylor polynomial to a quadratic using ancilla gadgets. Mapping the real-valued quadratic to a fixed-precision binary quadratic. Mapping the fully coupled binary quadratic to a partially coupled spherical Chimera graph using ancilla gadgets. At present the D-Wave contains 512 qbits (with 1024 and 2048 qbit machines due in the next two years); this machine size allows us to estimate only 3 state variables at each satellite overpass. However, QAC's solve optimization problems using a physical (quantum) system, and therefore do not require iterations or calculation of model adjoints. This has the potential to revolutionize our ability to efficiently perform variational data assimilation, as the size of these computers grows in the coming years.

Reducing the Impact of Sampling Bias in NASA MODIS and VIIRS Level 3 Satellite Derived IR SST Observations over the Arctic

NASA Astrophysics Data System (ADS)

Minnett, P. J.; Liu, Y.; Kilpatrick, K. A.

2016-12-01

Sea-surface temperature (SST) measurements by satellites in the northern hemisphere high latitudes confront several difficulties. Year-round prevalent clouds, effects near ice edges, and the relative small difference between SST and low-level cloud temperatures lead to a significant loss of infrared observations regardless of the more frequent polar satellite overpasses. Recent research (Liu and Minnett, 2016) identified sampling issues in the Level 3 NASA MODIS SST products when 4km observations are aggregated into global grids at different time and space scales, particularly in the Arctic, where a binary decision cloud mask designed for global data is often overly conservative at high latitudes and results in many gaps and missing data. This under sampling of some Arctic regions results in a warm bias in Level 3 products, likely a result of warmer surface temperature, more distant from the ice edge, being identified more frequently as cloud free. Here we present an improved method for cloud detection in the Arctic using a majority vote from an ensemble of four classifiers trained based on an Alternative Decision Tree (ADT) algorithm (Freund and Mason 1999, Pfahringer et. al. 2001). This new cloud classifier increases sampling of clear pixel by 50% in several regions and generally produces cooler monthly average SST fields in the ice-free Arctic, while still retaining the same error characteristics at 1km resolution relative to in situ observations. SST time series of 12 years of MODIS (Aqua and Terra) and more recently VIIRS sensors are compared and the improvements in errors and uncertainties resulting from better cloud screening for Level 3 gridded products are assessed and summarized.

A Lagrangian analysis of cold cloud clusters and their life cycles with satellite observations

PubMed Central

Esmaili, Rebekah Bradley; Tian, Yudong; Vila, Daniel Alejandro; Kim, Kyu-Myong

2018-01-01

Cloud movement and evolution signify the complex water and energy transport in the atmosphere-ocean-land system. Detecting, clustering, and tracking clouds as semi-coherent cluster objects enables study of their evolution which can complement climate model simulations and enhance satellite retrieval algorithms, where there are large gaps between overpasses. Using an area-overlap cluster tracking algorithm, in this study we examine the trajectories, horizontal extent, and brightness temperature variations of millions of individual cloud clusters over their lifespan, from infrared satellite observations at 30-minute, 4-km resolution, for a period of 11 years. We found that the majority of cold clouds were both small and short-lived and that their frequency and location are influenced by El Niño. More importantly, this large sample of individually tracked clouds shows their horizontal size and temperature evolution. Longer lived clusters tended to achieve their temperature and size maturity milestones at different times, while these stages often occurred simultaneously in shorter lived clusters. On average, clusters with this lag also exhibited a greater rainfall contribution than those where minimum temperature and maximum size stages occurred simultaneously. Furthermore, by examining the diurnal cycle of cluster development over Africa and the Indian subcontinent, we observed differences in the local timing of the maximum occurrence at different life cycle stages. Over land there was a strong diurnal peak in the afternoon while over the ocean there was a semi-diurnal peak composed of longer-lived clusters in the early morning hours and shorter-lived clusters in the afternoon. Building on regional specific work, this study provides a long-term, high-resolution, and global survey of object-based cloud characteristics. PMID:29744257

Deriving temporally continuous soil moisture estimations at fine resolution by downscaling remotely sensed product

NASA Astrophysics Data System (ADS)

Jin, Yan; Ge, Yong; Wang, Jianghao; Heuvelink, Gerard B. M.

2018-06-01

Land surface soil moisture (SSM) has important roles in the energy balance of the land surface and in the water cycle. Downscaling of coarse-resolution SSM remote sensing products is an efficient way for producing fine-resolution data. However, the downscaling methods used most widely require full-coverage visible/infrared satellite data as ancillary information. These methods are restricted to cloud-free days, making them unsuitable for continuous monitoring. The purpose of this study is to overcome this limitation to obtain temporally continuous fine-resolution SSM estimations. The local spatial heterogeneities of SSM and multiscale ancillary variables were considered in the downscaling process both to solve the problem of the strong variability of SSM and to benefit from the fusion of ancillary information. The generation of continuous downscaled remote sensing data was achieved via two principal steps. For cloud-free days, a stepwise hybrid geostatistical downscaling approach, based on geographically weighted area-to-area regression kriging (GWATARK), was employed by combining multiscale ancillary variables with passive microwave remote sensing data. Then, the GWATARK-estimated SSM and China Soil Moisture Dataset from Microwave Data Assimilation SSM data were combined to estimate fine-resolution data for cloudy days. The developed methodology was validated by application to the 25-km resolution daily AMSR-E SSM product to produce continuous SSM estimations at 1-km resolution over the Tibetan Plateau. In comparison with ground-based observations, the downscaled estimations showed correlation (R ≥ 0.7) for both ascending and descending overpasses. The analysis indicated the high potential of the proposed approach for producing a temporally continuous SSM product at fine spatial resolution.

Evaluating the intersection of a regional wildlife connectivity network with highways.

PubMed

Cushman, Samuel A; Lewis, Jesse S; Landguth, Erin L

2013-01-01

Reliable predictions of regional-scale population connectivity are needed to prioritize conservation actions. However, there have been few examples of regional connectivity models that are empirically derived and validated. The central goals of this paper were to (1) evaluate the effectiveness of factorial least cost path corridor mapping on an empirical resistance surface in reflecting the frequency of highway crossings by American black bear, (2) predict the location and predicted intensity of use of movement corridors for American black bear, and (3) identify where these corridors cross major highways and rank the intensity of these crossings. We used factorial least cost path modeling coupled with resistant kernel analysis to predict a network of movement corridors across a 30.2 million hectare analysis area in Montana and Idaho, USA. Factorial least cost path corridor mapping was associated with the locations of actual bear highway crossings. We identified corridor-highway intersections and ranked these based on corridor strength. We found that a major wildlife crossing overpass structure was located close to one of the most intense predicted corridors, and that the vast majority of the predicted corridor network was "protected" under federal management. However, narrow, linear corridors connecting the Greater Yellowstone Ecosystem to the rest of the analysis area had limited protection by federal ownership, making these additionally vulnerable to habitat loss and fragmentation. Factorial least cost path modeling coupled with resistant kernel analysis provides detailed, synoptic information about connectivity across populations that vary in distribution and density in complex landscapes. Specifically, our results could be used to quantify the structure of the connectivity network, identify critical linkage nodes and core areas, map potential barriers and fracture zones, and prioritize locations for mitigation, restoration and conservation actions.

Radiometric consistency assessment of hyperspectral infrared sounders

NASA Astrophysics Data System (ADS)

Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

2015-07-01

The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark datasets for both inter-calibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and -B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through one year of simultaneous nadir overpass (SNO) observations to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the longwave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both Polar and Tropical SNOs. The combined global SNO datasets indicate that, the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 comparison spectral regions and they range from 0.15 to 0.21 K in the remaining 4 spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

Radiometric consistency assessment of hyperspectral infrared sounders

NASA Astrophysics Data System (ADS)

Wang, L.; Han, Y.; Jin, X.; Chen, Y.; Tremblay, D. A.

2015-11-01

The radiometric and spectral consistency among the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared Sounder (CrIS) is fundamental for the creation of long-term infrared (IR) hyperspectral radiance benchmark data sets for both intercalibration and climate-related studies. In this study, the CrIS radiance measurements on Suomi National Polar-orbiting Partnership (SNPP) satellite are directly compared with IASI on MetOp-A and MetOp-B at the finest spectral scale and with AIRS on Aqua in 25 selected spectral regions through simultaneous nadir overpass (SNO) observations in 2013, to evaluate radiometric consistency of these four hyperspectral IR sounders. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The results indicate that CrIS agrees well with IASI on MetOp-A and IASI on MetOp-B at the long-wave IR (LWIR) and middle-wave IR (MWIR) bands with 0.1-0.2 K differences. There are no apparent scene-dependent patterns for BT differences between CrIS and IASI for individual spectral channels. CrIS and AIRS are compared at the 25 spectral regions for both polar and tropical SNOs. The combined global SNO data sets indicate that the CrIS-AIRS BT differences are less than or around 0.1 K among 21 of 25 spectral regions and they range from 0.15 to 0.21 K in the remaining four spectral regions. CrIS-AIRS BT differences in some comparison spectral regions show weak scene-dependent features.

Characterization of Dust Properties during ACE-Asia and PRIDE: A Column Satellite-Surface Perspective

NASA Technical Reports Server (NTRS)

Lau, William K. M. (Technical Monitor); Tsay, Si-Chee; Hsu, N. Christina; Herman, Jay R.; Ji, Q. Jack

2002-01-01

Many recent field experiments are designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentration over particular pathways around the globe. For example, the ACE-Asia (Aerosol Characterization Experiment-Asia) was conducted from March-May 2001 in the vicinity of the Taklimakan and Gobi deserts, East Coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). The PRIDE (Puerto RIco Dust Experiment, July 2000) was designed to measure the properties of Saharan dust transported across the Atlantic Ocean to the Caribbean. Dust particles typically originate in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of dust aerosols is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the ocean. During ACE-Asia and PRIDE we had measured aerosol physical/optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from ground-based remote sensing. The inclusion of flux measurements permits the determination of aerosol radiative flux in addition to measurements of loading and optical depth. At the time of the Terra/MODIS, SeaWiFS, TOMS and other satellite overpasses, these ground-based observations can provide valuable data to compare with satellite retrievals over land. We will present the results and discuss their implications in regional climatic effects.

Characterizing the physical-basis of orographic rainfall retrieval errors due to terrain artifacts on GPM-DPR reflectivity profiles

NASA Astrophysics Data System (ADS)

Arulraj, M.; Barros, A. P.

2017-12-01

GPM-DPR reflectivity profiles in mountainous regions are severely handicapped by low level ground-clutter artifacts which have different error characteristics depending on landform (upwind slopes of high mountains versus complex topography in middle-mountains) and precipitation regime. These artifacts result in high detection and estimation errors especially in mid-latitude and tropical mountain regions where low-level light precipitation and complex multi-layer clouds interact with incoming storms. Here, we present results assessment studies in the Southern Appalachian Mountains (SAM) and preliminary results over the eastern slopes of the Andes using ground-based observations from the long-term hydrometeorological networks and model studies toward developing a physically-based framework to systematically identify and attribute measurement errors. Specifically, the focus is on events when GPM-DPR Ka- and Ku- Band precipitation radar misses low-level precipitation with vertical altitude less than 2 km AGL (above ground level). For this purpose, ground-based MRR and Parsivel disdrometer observations near the surface are compared with the reflectivity profiles observed by the GPM-DPR overpasses, the raindrop-size spectra are used to classify the precipitation regime associated with different classes of detection and estimation errors. This information will be used along with a coupled rainfall dynamics and radar simulator model to 1) merge the low-level GPM-DPR measured reflectivity with the MRR reflectivities optimally under strict physically-based constraints and 2) build a library of reflectivity profile corrections. Finally, preliminary 4D analysis of the organization of reflectivity correction modes, microphysical regimes, topography and storm environment will be presented toward developing a general physically-based error model.

Modeling diurnal land temperature cycles over Los Angeles using downscaled GOES imagery

NASA Astrophysics Data System (ADS)

Weng, Qihao; Fu, Peng

2014-11-01

Land surface temperature is a key parameter for monitoring urban heat islands, assessing heat related risks, and estimating building energy consumption. These environmental issues are characterized by high temporal variability. A possible solution from the remote sensing perspective is to utilize geostationary satellites images, for instance, images from Geostationary Operational Environmental System (GOES) and Meteosat Second Generation (MSG). These satellite systems, however, with coarse spatial but high temporal resolution (sub-hourly imagery at 3-10 km resolution), often limit their usage to meteorological forecasting and global climate modeling. Therefore, how to develop efficient and effective methods to disaggregate these coarse resolution images to a proper scale suitable for regional and local studies need be explored. In this study, we propose a least square support vector machine (LSSVM) method to achieve the goal of downscaling of GOES image data to half-hourly 1-km LSTs by fusing it with MODIS data products and Shuttle Radar Topography Mission (SRTM) digital elevation data. The result of downscaling suggests that the proposed method successfully disaggregated GOES images to half-hourly 1-km LSTs with accuracy of approximately 2.5 K when validated against with MODIS LSTs at the same over-passing time. The synthetic LST datasets were further explored for monitoring of surface urban heat island (UHI) in the Los Angeles region by extracting key diurnal temperature cycle (DTC) parameters. It is found that the datasets and DTC derived parameters were more suitable for monitoring of daytime- other than nighttime-UHI. With the downscaled GOES 1-km LSTs, the diurnal temperature variations can well be characterized. An accuracy of about 2.5 K was achieved in terms of the fitted results at both 1 km and 5 km resolutions.

Diurnal variability in carbon and nitrogen pools within Chesapeake Bay and northern Gulf of Mexico: implications for future ocean color satellite sensors

NASA Astrophysics Data System (ADS)

Mannino, A.; Novak, M. G.; Tzortziou, M.; Salisbury, J.

2016-02-01

Relative to their areal extent, estuaries and coastal ocean ecosystems contribute disproportionately more to global biogeochemical cycling of carbon, nitrogen and other elements compared to the open ocean. Applying ocean color satellite data to study biological and biogeochemical processes within coastal ecosystems is challenging due to the complex mixtures of aquatic constituents derived from terrestrial, anthropogenic, and marine sources, human-impacted atmospheric properties, presence of clouds during satellite overpass, fine-scale spatial gradients, and time-varying processes on diurnal scales that cannot be resolved with current sensors. On diurnal scales, biological, photochemical, and biogeochemical processes are regulated by the variation in solar radiation. Other physical factors, such as tides, river discharge, estuarine and coastal ocean circulation, wind-driven mixing, etc., impart further variability on biological and biogeochemical processes on diurnal to multi-day time scales. Efforts to determine the temporal frequency required from a NASA GEO-CAPE ocean color satellite sensor to discern diurnal variability C and N stocks, fluxes and productivity culminated in field campaigns in the Chesapeake Bay and northern Gulf of Mexico. Near-surface drogues were released and tracked in quasi-lagrangian space to monitor hourly changes in community production, C and N stocks, and optical properties. While only small diurnal changes were observed in dissolved organic carbon (DOC) and colored dissolved organic matter (CDOM) absorption in Chesapeake Bay, substantial variation in particulate organic carbon (POC) and nitrogen (PN), chlorophyll-a, and inorganic nitrogen (DIN) were measured. Similar or greater diurnal changes in POC, PN, chlorophyll-a and DIN were found in Gulf of Mexico nearshore and offshore sites. These results suggest that satellite observations at hourly frequency are desirable to capture diurnal variability in carbon and nitrogen stocks, fluxes and productivity within coastal ecosystems.

Recovery of forest structure and spectral properties after selective logging in lowland Bolivia.

PubMed

Broadbent, Eben N; Zarin, Daniel J; Asner, Gregory P; Peña-Claros, Marielos; Cooper, Amanda; Littell, Ramon

2006-06-01

Effective monitoring of selective logging from remotely sensed data requires an understanding of the spatial and temporal thresholds that constrain the utility of those data, as well as the structural and ecological characteristics of forest disturbances that are responsible for those constraints. Here we assess those thresholds and characteristics within the context of selective logging in the Bolivian Amazon. Our study combined field measurements of the spatial and temporal dynamics of felling gaps and skid trails ranging from <1 to 19 months following reduced-impact logging in a forest in lowland Bolivia with remote-sensing measurements from simultaneous monthly ASTER satellite overpasses. A probabilistic spectral mixture model (AutoMCU) was used to derive per-pixel fractional cover estimates of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV), and soil. Results were compared with the normalized difference in vegetation index (NDVI). The forest studied had considerably lower basal area and harvest volumes than logged sites in the Brazilian Amazon where similar remote-sensing analyses have been performed. Nonetheless, individual felling-gap area was positively correlated with canopy openness, percentage liana coverage, rates of vegetation regrowth, and height of remnant NPV. Both liana growth and NPV occurred primarily in the crown zone of the felling gap, whereas exposed soil was limited to the trunk zone of the gap. In felling gaps >400 m2, NDVI, and the PV and NPV fractions, were distinguishable from unlogged forest values for up to six months after logging; felling gaps <400 m2 were distinguishable for up to three months after harvest, but we were entirely unable to distinguish skid trails from our analysis of the spectral data.

Multi-sensor satellite monitoring of ash and SO2 volcanic plume in support to aviation control

NASA Astrophysics Data System (ADS)

Brenot, Hugues; Theys, Nicolas; Clarisse, Lieven; van Geffen, Jos; van Gent, Jeroen; Van Roozendael, Michel; van der A, Ronald; Hurtmans, Daniel; Coheur, Pierre-Francois; Clerbaux, Cathy; Valks, Pieter; Hedelt, Pascal; Prata, Fred; Rasson, Olivier; Sievers, Klaus; Zehner, Claus

2014-05-01

The 'Support to Aviation Control Service' (SACS; http://sacs.aeronomie.be) is an ESA-funded project hosted by the Belgian Institute for Space Aeronomy since 2007. The service provides near real-time (NRT) global volcanic ash and SO2 observations, as well as notifications in case of volcanic eruptions (success rate >95% for ash and SO2). SACS is based on the combined use of UV-visible (OMI, GOME-2 MetOp-A, GOME-2 MetOp-B) and infrared (AIRS, IASI MetOp-A, IASI MetOp-B) satellite instruments. The SACS service is primarily designed to support the Volcanic Ash Advisory Centers (VAACs) in their mandate to gather information on volcanic clouds and give advice to airline and air traffic control organisations. SACS also serves other users that subscribe to the service, in particular local volcano observatories, research scientists and airliner pilots. When a volcanic eruption is detected, SACS issues a warning that takes the form of a notification sent by e-mail to users. The SACS notification points to a dedicated web page where all relevant information is available and can be visualised with user-friendly tools. Information about the volcanic plume height from GOME-2 (MetOp-A and MetOp-B) are also available. The strength of a multi-sensor approach relies in the use of satellite data with different overpasses times, minimising the time-lag for detection and enhancing the reliability of such alerts. This presentation will give an overview of the SACS service, and of the different techniques used to detect volcanic plumes (ash, SO2 and plume height). It will also highlight the strengths and limitations of the service and measurements, and some perspectives.

Validation of MODIS aerosol optical depth product over China using CARSNET measurements

NASA Astrophysics Data System (ADS)

Xie, Yong; Zhang, Yan; Xiong, Xiaoxiong; Qu, John J.; Che, Huizheng

2011-10-01

This study evaluates Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depth (AOD) retrievals with ground measurements collected by the China Aerosol Remote Sensing NETwork (CARSNET). In current stage, the MODIS Collection 5 (C5) AODs are retrieved by two distinct algorithms: the Dark Target (DT) and the Deep Blue (DB). The CARSNET AODs are derived with measurements of Cimel Electronique CE-318, the same instrument deployed by the AEROsol Robotic Network (AEROENT). The collocation is performed by matching each MODIS AOD pixel (10 × 10 km 2) to CARSNET AOD mean within 7.5 min of satellite overpass. Four-year comparisons (2005-2008) of MODIS/CARSNET at ten sites show the performance of MODIS AOD retrieval is highly dependent on the underlying land surface. The MODIS DT AODs are on average lower than the CARSNET AODs by 6-30% over forest and grassland areas, but can be higher by up to 54% over urban area and 95% over desert-like area. More than 50% of the MODIS DT AODs fall within the expected error envelope over forest and grassland areas. The MODIS DT tends to overestimate for small AOD at urban area. At high vegetated area it underestimates for small AOD and overestimates for large AOD. Generally, its quality reduces with the decreasing AOD value. The MODIS DB is capable of retrieving AOD over desert but with a significant underestimation at CARSNET sites. The best retrieval of the MODIS DB is over grassland area with about 70% retrievals within the expected error. The uncertainties of MODIS AOD retrieval from spatial-temporal collocation and instrument calibration are discussed briefly.

A prototype data assimilation framework for generating spatiotemporally continuous SWOT data products

NASA Astrophysics Data System (ADS)

Andreadis, K.; Margulis, S. A.; Li, D.; Lettenmaier, D. P.

2017-12-01

The Surface Water and Ocean Topography (SWOT) satellite will provide critical surface water observations for the hydrologic community. However, production of key SWOT variables, such as river discharge and surface inundation, as well as lake, reservoir, and wetland storage change will be complicated by the discontinuity of the observations in space and time. A methodology that generates products with spatially and temporally continuous fields based on SWOT observables would be highly desirable. Data assimilation provides a mechanism for merging observations from SWOT with model predictions in order to produce estimates of quantities such as river discharge, storage change, and water heights for locations and times when there is no satellite overpass or other constraints (such as layover) render the measurement unusable. We describe here a prototype assimilation system with application to the Upper Mississippi basin, implemented using synthetic SWOT observations. We use a hydrologic model (VIC) coupled with a hydrodynamic model (LISFLOOD-FP) which generates "true" fields of surface water variables. The true fields are then used to generate synthetic SWOT observations using the SWOT Instrument Simulator. We also perform a "first-guess" (or open-loop) simulation with the coupled model using a configuration that contains errors representative of the imperfect knowledge of parameters and input data, including channel topography, bankfull widths and depths, and inflows, to create an ensemble of 20 model trajectories. Subsequently we assimilate the synthetic SWOT observations into the open-loop model results to estimate water surface elevation, discharge, and storage change. Our preliminary results using three data assimilation strategies show that all improve the water surface elevation estimate accuracy by 25% - 35% for a river reach of the upper Mississippi River. Ongoing work is examining whether the improved water surface elevation estimates propagate to improvements in river discharge.

Hydrodynamic modeling in the Peace-Athabasca Delta for the upcoming Surface Water and Ocean Topography (SWOT) mission

NASA Astrophysics Data System (ADS)

Bergeron, J.; Carter, T.; Langlois, S.; Leconte, R.; Peters, D.; Pietroniro, A.; Russell, M.; Saint-Jean, R.; Siles, G. L.; Trudel, M.

2017-12-01

The upcoming Surface Water and Ocean Topography (SWOT) mission aims to retrieve water levels elevations via satellite remote sensing. In anticipation of the launch, scheduled for 2021, multiple regions are selected for calibration/validation purposes. The Peace-Athabasca Delta (PAD), a fresh water wetland complex located in the northeastern part of Alberta, Canada, is one of those regions. The PAD comprises numerous lakes and rivers, including Lake Mamawi and the Athabasca River presented in this study. Since it is a region of interest for many projects, including this one, the region has been monitored via multiple types of observations over time, including airborne LiDAR, water level, discharge, bathymetric surveys retrieved from traditional point-measurements tied to Global Positioning System and from an acoustic Doppler current profiler, and more recently, the airborne support instrument AirSWOT. Using a SWOT imagery simulator and a 2D hydrodynamic model (H2D2), we model the hydrologic steady-state conditions of Lake Mamawi and the Athabasca River, as well as the simulated SWOT imagery resulting from a virtual overpass. A digital terrain model derived from airborne LiDAR and bathymetric surveys, as well as water level and discharge measurements collected during the summers of 2016 and 2017, are used to provide a calibrated H2D2 model, from which simulated SWOT images are generated. The objectives of the research are to explore the capabilities of the simulated SWOT data to 1) calibrate and validate the H2D2 model over the PAD, and 2) to improve the water balance of the PAD in a synthetic context.

ANALYSIS OF WATER AND ENERGY FLUXES USING SATELLITE, ENERGY BALANCE MODELING AND OBSERVATIONS (Invited)

NASA Astrophysics Data System (ADS)

Irmak, A.

2009-12-01

Surface energy fluxes, including net radiation (Rn), sensible heat (H), latent heat (LE), and soil heat flux (G) are critical in surface energy balance of any terrain or landscapes. Estimation or measurement of these energy fluxes is important for completing the water balance in terrestrial ecosystems, and therefore accurately predicting the effects of global climate and land use change. The objectives of this study were to (1) use METRICtm (Mapping Evapotranspiration at high Resolution using Internalized Calibration) model for estimating land surface energy fluxes in Nebraska (NE) by utilizing satellite remote sensing data, (2) identify model bias in energy balance components compared with measurements from Bowen Ratio Energy Balance System (BREBS) in a subsurface drip-irrigated maize field in South-central Nebraska, and (3) understand the partitioning of available energy into latent heat for corn and soybean cropping systems at large scale. A total of 15 Landsat images were processed to estimate instantaneous surface energy fluxes at Landsat overpasses with METRIC model. Results showed that the model predictions of the surface energy fluxes and daily evapotranspiration were correlated well with the BREBS measurements. There is a need, however, to test the performance of the model with in-situ observations in other locations with different dataset before utilizing it for crucial water regulatory and policy decisions. The METRICtm approach illustrated how an ‘off-the-shelf’ model can be applied operationally over a significant time period and how that model behaves. The findings makes considerable contribution to our understanding of estimating land surface energy fluxes using remote sensing approach and experimentally describes the operational characteristics of METRICtm and presents its limitations.

ETO cloud studies for FIRE 2, part 1

NASA Technical Reports Server (NTRS)

Sassen, Kenneth

1992-01-01

This research program in support of Project FIRE (First ISCCP Regional Experiment) involved two efforts. The results of the first effort, which were in direct support of the Extended Time Observations (ETO) component, are described here. Over the period from June 1990 through May 1991, our remote sensing systems were applied to providing ground-truth cirrus cloud observations for a total of 71 NOAA polar orbiting satellite overpasses. (Chronological tables of this effort are provided.) The primary remote sensor was a dual-polarization ruby (0.694 microns wavelength) lidar, although mid-way through the program we added a number of radiometers to assess the surface radiation budget and cirrus cloud infrared emittance, and some supplemental observations from a Ka-band (8.6 mm) radar were also collected. These studies were conducted from the Facility for Atmospheric Remote Sensing (FARS) at 40 degrees 46 minutes 00 seconds north latitude and 111 degrees 49 minutes 38 seconds east longitude. We also investigated the unusual characteristics of a subset of ETO case studies involving cirrus that generated solar and lunar corona displays. As we reported recently (reprint attached), these cirrus were atypically high and cold in relation to our total midlatitude cloud sample, and were comprised of unexpectedly small ice crystals from 10 to 30 microns in dimension. This finding lends some credence to the so-called cirrus small particle radiative anomaly, but only for very cold (less than -60 C) cirrus clouds. In a supplement, we will describe the design and testing of a prototype cirrus cloud polar nephelometer, which we constructed as part of our second research effort, to allow scattering phase functions to be obtained in future in situ cirrus research.

Development of large scale riverine terrain-bathymetry dataset by integrating NHDPlus HR with NED,CoNED and HAND data

NASA Astrophysics Data System (ADS)

Li, Z.; Clark, E. P.

2017-12-01

Large scale and fine resolution riverine bathymetry data is critical for flood inundation modelingbut not available over the continental United States (CONUS). Previously we implementedbankfull hydraulic geometry based approaches to simulate bathymetry for individual riversusing NHDPlus v2.1 data and 10 m National Elevation Dataset (NED). USGS has recentlydeveloped High Resolution NHD data (NHDPlus HR Beta) (USGS, 2017), and thisenhanced dataset has a significant improvement on its spatial correspondence with 10 m DEM.In this study, we used this high resolution data, specifically NHDFlowline and NHDArea,to create bathymetry/terrain for CONUS river channels and floodplains. A software packageNHDPlus Inundation Modeler v5.0 Beta was developed for this project as an Esri ArcGIShydrological analysis extension. With the updated tools, raw 10 m DEM was first hydrologicallytreated to remove artificial blockages (e.g., overpasses, bridges and eve roadways, etc.) usinglow pass moving window filters. Cross sections were then automatically constructed along eachflowline to extract elevation from the hydrologically treated DEM. In this study, river channelshapes were approximated using quadratic curves to reduce uncertainties from commonly usedtrapezoids. We calculated underneath water channel elevation at each cross section samplingpoint using bankfull channel dimensions that were estimated from physiographicprovince/division based regression equations (Bieger et al. 2015). These elevation points werethen interpolated to generate bathymetry raster. The simulated bathymetry raster wasintegrated with USGS NED and Coastal National Elevation Database (CoNED) (whereveravailable) to make seamless terrain-bathymetry dataset. Channel bathymetry was alsointegrated to the HAND (Height above Nearest Drainage) dataset to improve large scaleinundation modeling. The generated terrain-bathymetry was processed at WatershedBoundary Dataset Hydrologic Unit 4 (WBDHU4) level.

The Mesospheric Sodium Layer as a Remotely, Optically Pumped Magnetometer for Investigation of Birkeland Currents

NASA Astrophysics Data System (ADS)

Matzka, J.; Johnsen, M. G.; Hoppe, U. P.; Serrano, A.

2016-12-01

By means of optical pumping, it is possible to use the naturally occurring sodium layer in the mesosphere to measure Earth's scalar magnetic field at 90 km above ground. This is an altitude not accessible by other means than rockets, which only will provide point measurements of very short time scales. We are planning to modify the sodium lidar at ALOMAR in Northern Norway to be able, for the first time, to measure and monitor the magnetic field in situ in the high latitude mesosphere over longer time scales. The planned modifications to the lidar instrument will allow alternating between the new magnetometer mode and its present mode for atmospheric temperatures and winds. The technique, which has been proposed earlier for measurements at low or mid-latitudes for studies of Earth's internal magnetic field, will in our project be applied to high latitudes in the auroral zone. This opens for a completely new domain of measurements of externally generated geomagnetic variations related to currents in the magnetosphere-ionosphere system. In particular, we aim to measure the magnetic field variations in close vicinity to Birkeland currents associated with particle precipitation events penetrating to altitudes below 90 km and small-scale, discrete auroral arcs. It is, furthermore, anticipated that it will be possible to detect horizontal current structures in the E-layer on much smaller length scales than it is presently possible from ground observations alone. During the project we plan take advantage of the rich space science infrastructure located in northern Norway, including ALOMAR, EISCAT and the Tromsø Geophysical Observatory magnetometer network. If possible, we also aim to make measurements in conjunction with overpasses of the SWARM satellites.

Combining model and satellite data to investigate the effect of light absorbing impurities on snow melt and discharge generation

NASA Astrophysics Data System (ADS)

Matt, F.; Burkhart, J. F.

2017-12-01

Light absorbing impurities in snow and ice (LAISI) originating from atmospheric deposition enhance snow melt by increasing the absorption of solar radiation. The consequences are a shortening of the snow cover duration due to increased snow melt and, with respect to hydrologic processes, a temporal shift in the discharge generation. However, the effects as simulated in numerical models have large uncertainties. These uncertainties originate mainly from uncertainties in the wet and dry deposition of light absorbing aerosols, limitations in the model representation of the snowpack, and the lack of observable variables required to estimate model parameters. This leads to high uncertainties in the additional energy absorbed by the snow due to the presence of LAISI (the so called radiative forcing of LAISI), a key variable in understanding snowpack energy-balance dynamics. In this study, we present an approach combining distributed model simulations on the catchment scale and remotely sensed radiative forcing from LAISI in order to evaluate and improve model predictions. In a case study, we assess the effect of LAISI on snow melt and discharge generation in a high mountain catchment located in the western Himalaya using the distributed hydrologic model, Shyft. The snow albedo is hereby calculated from a radiative transfer model for snow, taking the increased absorption of solar radiation by LAISI into account. LAISI mixing ratios in snow are determined from atmospheric aerosol deposition rates. To asses the quality of our simulations, we model the instantaneous clear sky radiative forcing at MODIS overpass times, and compare it to the MODIS Dust Radiative Forcing in Snow (MODDRFS) satellite product. By scaling the deposition input to the model, we can optimize the simulated radiative forcing towards the satellite observations.

Evaluating multiple causes of persistent low microwave backscatter from Amazon forests after the 2005 drought.

PubMed

Frolking, Steve; Hagen, Stephen; Braswell, Bobby; Milliman, Tom; Herrick, Christina; Peterson, Seth; Roberts, Dar; Keller, Michael; Palace, Michael

2017-01-01

Amazonia has experienced large-scale regional droughts that affect forest productivity and biomass stocks. Space-borne remote sensing provides basin-wide data on impacts of meteorological anomalies, an important complement to relatively limited ground observations across the Amazon's vast and remote humid tropical forests. Morning overpass QuikScat Ku-band microwave backscatter from the forest canopy was anomalously low during the 2005 drought, relative to the full instrument record of 1999-2009, and low morning backscatter persisted for 2006-2009, after which the instrument failed. The persistent low backscatter has been suggested to be indicative of increased forest vulnerability to future drought. To better ascribe the cause of the low post-drought backscatter, we analyzed multiyear, gridded remote sensing data sets of precipitation, land surface temperature, forest cover and forest cover loss, and microwave backscatter over the 2005 drought region in the southwestern Amazon Basin (4°-12°S, 66°-76°W) and in adjacent 8°x10° regions to the north and east. We found moderate to weak correlations with the spatial distribution of persistent low backscatter for variables related to three groups of forest impacts: the 2005 drought itself, loss of forest cover, and warmer and drier dry seasons in the post-drought vs. the pre-drought years. However, these variables explained only about one quarter of the variability in depressed backscatter across the southwestern drought region. Our findings indicate that drought impact is a complex phenomenon and that better understanding can only come from more extensive ground data and/or analysis of frequent, spatially-comprehensive, high-resolution data or imagery before and after droughts.

IoSiS: a radar system for imaging of satellites in space

NASA Astrophysics Data System (ADS)

Jirousek, M.; Anger, S.; Dill, S.; Schreiber, E.; Peichl, M.

2017-05-01

Space debris nowadays is one of the main threats for satellite systems especially in low earth orbit (LEO). More than 700,000 debris objects with potential to destroy or damage a satellite are estimated. The effects of an impact often are not identifiable directly from ground. High-resolution radar images are helpful in analyzing a possible damage. Therefor DLR is currently developing a radar system called IoSiS (Imaging of Satellites in Space), being based on an existing steering antenna structure and our multi-purpose high-performance radar system GigaRad for experimental investigations. GigaRad is a multi-channel system operating at X band and using a bandwidth of up to 4.4 GHz in the IoSiS configuration, providing fully separated transmit (TX) and receive (RX) channels, and separated antennas. For the observation of small satellites or space debris a highpower traveling-wave-tube amplifier (TWTA) is mounted close to the TX antenna feed. For the experimental phase IoSiS uses a 9 m TX and a 1 m RX antenna mounted on a common steerable positioner. High-resolution radar images are obtained by using Inverse Synthetic Aperture Radar (ISAR) techniques. The guided tracking of known objects during overpass allows here wide azimuth observation angles. Thus high azimuth resolution comparable to the range resolution can be achieved. This paper outlines technical main characteristics of the IoSiS radar system including the basic setup of the antenna, the radar instrument with the RF error correction, and the measurement strategy. Also a short description about a simulation tool for the whole instrument and expected images is shown.

Initial analysis from a lidar observation campaign of sugar cane fires in the central and western portion of the São Paulo State, Brazil

NASA Astrophysics Data System (ADS)

da Silva Lopes, Fábio Juliano; Held, Gerhard; Nakaema, Walter M.; Rodrigues, Patricia F.; Bassan, Jose M.; Landulfo, Eduardo

2011-11-01

The central and western portion of the Sao Paulo State has large areas of sugar cane plantations, and due to the growing demand for biofuels, the production is increasing every year. During the harvest period some plantation areas are burnt a few hours before the manual cutting, causing significant quantities of biomass burning aerosol to be injected into the atmosphere. During August 2010, a field campaign has been carried out in Ourinhos, situated in the south-western region of Sao Paulo State. A 2-channel Raman Lidar system and two meteorological S-Band Doppler Radars are used to indentify and quantify the biomass burning plumes. In addiction, CALIPSO Satellite observations were used to compare the aerosol optical properties detected in that region with those retrieved by Raman Lidar system. Although the campaign yielded 30 days of measurements, this paper will be focusing only one case study, when aerosols released from nearby sugar cane fires were detected by the Lidar system during a CALIPSO overpass. The meteorological radar, installed in Bauru, approximately 110 km northeast from the experimental site, had recorded "echoes" (dense smoke comprising aerosols) from several fires occurring close to the Raman Lidar system, which also detected an intense load of aerosol in the atmosphere. HYSPLIT model forward trajectories presented a strong indication that both instruments have measured the same air masss parcels, corroborated with the Lidar Ratio values from the 532 nm elastic and 607 nm Raman N2 channel analyses and data retrieved from CALIPSO have indicated the predominance of aerosol from biomass burning sources.

The International Space Station as a Key Platform to Synergize Observations of Fundamental Ecosystem Properties

NASA Astrophysics Data System (ADS)

Fisher, J. B.; Stavros, E. N.; Pavlick, R.; Hook, S. J.; Eldering, A.; Dubayah, R.; Schimel, D.

2016-12-01

Terrestrial ecosystems can be described in terms of trait composition, physiological function, and physical structure; all three of these are observable remotely to varying degrees. Yet, no mission is able to singularly capture all three together, thus inhibiting our ability to dynamically measure and describe ecosystems as holistic, integrated, and interconnected entities. The International Space Station (ISS) is a new platform for global ecology. The variable overpass time offers a key advantage to investigations interested in sampling over the diurnal cycle, critical to understanding ecosystem function. The ISS also offers another key advantage—financial; it is already there with funded astronaut cargo re-supply missions, so the cost of launch and platform do not need to be added onto new science missions, thereby enabling NASA to select more missions at lower costs. In 2018, NASA will begin sending a series of independently-selected missions to the ISS focused on terrestrial ecosystems. First, ECOSTRESS will produce thermal-based evapotranspiration (ET) data, among other products. OCO-3 will arrive a few months later to measure chlorophyll fluorescence (related to gross primary production, GPP) and atmospheric CO2. Finally, GEDI will produce LiDAR-based ecosystem structure (height, leaf area index, biomass). While each mission is independently developed and funded, the respective mission scientists are working together to bridge observations and leverage their unique contemporaneous and synergistic value for global ecology. A composition-based mission is still missing from the ISS, but airborne and other space agency missions may be leveraged. This talk will describe these ISS-based terrestrial ecosystem science missions, and discuss synergies that will enable the study of ecosystems as a whole that is larger than the sum of their parts.

Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

NASA Astrophysics Data System (ADS)

Tang, N. W.; Kirchstetter, T.; Martien, P. T.; Apte, J.

2015-12-01

Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate "head-end" power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

NASA Astrophysics Data System (ADS)

Tang, Nicholas W.; Apte, Joshua S.; Martien, Philip T.; Kirchstetter, Thomas W.

2015-08-01

Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate ;head-end; power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

Quantifying Fractional Ground Cover on the Climate Sensitive High Plains Using AVIRIS and Landsat TM Data

NASA Technical Reports Server (NTRS)

Warner, Amanda Susan

2002-01-01

The High Plains is an economically important and climatologically sensitive region of the United States and Canada. The High Plains contain 100,000 sq km of Holocene sand dunes and sand sheets that are currently stabilized by natural vegetation. Droughts and the larger threat of global warming are climate phenomena that could cause depletion of natural vegetation and make this region susceptible to sand dune reactivation. This thesis is part of a larger study that is assessing the effect of climate variability on the natural vegetation that covers the High Plains using Landsat 5 and Landsat 7 data. The question this thesis addresses is how can fractional vegetation cover be mapped with the Landsat instruments using linear spectral mixture analysis and to what accuracy. The method discussed in this thesis made use of a high spatial and spectral resolution sensor called AVIRIS (Airborne Visible and Infrared Imaging Spectrometer) and field measurements to test vegetation mapping in three Landsat 7 sub-scenes. Near-simultaneous AVIRIS images near Ft. Morgan, Colorado and near Logan, New Mexico were acquired on July 10, 1999 and September 30, 1999, respectively. The AVIRIS flights preceded Landsat 7 overpasses by approximately one hour. These data provided the opportunity to test spectral mixture algorithms with AVIRIS and to use these data to constrain the multispectral mixed pixels of Landsat 7. The comparisons of mixture analysis between the two instruments showed that AVIRIS endmembers can be used to unmix Landsat 7 data with good estimates of soil cover, and reasonable estimates of non-photosynthetic vegetation and green vegetation. Landsat 7 derived image endmembers correlate with AVIRIS fractions, but the error is relatively large and does not give a precise estimate of cover.

Monsoon Convective During the South China Sea Monsoon Experiment: Observations from Ground-Based Radar and the TRMM Satellite

NASA Technical Reports Server (NTRS)

Cifelli, Rob; Rickenbach, Tom; Halverson, Jeff; Keenan, Tom; Kucera, Paul; Atkinson, Lester; Fisher, Brad; Gerlach, John; Harris, Kathy; Kaufman, Cristina

1999-01-01

A main goal of the recent South China Sea Monsoon Experiment (SCSMEX) was to study convective processes associated with the onset of the Southeast Asian summer monsoon. The NASA TOGA C-band scanning radar was deployed on the Chinese research vessel Shi Yan #3 for two 20 day cruises, collecting dual-Doppler measurements in conjunction with the BMRC C-Pol dual-polarimetric radar on Dongsha Island. Soundings and surface meteorological data were also collected with an NCAR Integrated Sounding System (ISS). This experiment was the first major tropical field campaign following the launch of the Tropical Rainfall Measuring Mission (TRMM) satellite. These observations of tropical oceanic convection provided an opportunity to make comparisons between surface radar measurements and the Precipitation Radar (PR) aboard the TRMM satellite in an oceanic environment. Nearly continuous radar operations were conducted during two Intensive Observing Periods (IOPS) straddling the onset of the monsoon (5-25 May 1998 and 5-25 June 1998). Mesoscale lines of convection with widespread regions of both trailing and forward stratiform precipitation were observed following the onset of the active monsoon in the northern South China Sea region. The vertical structure of the convection during periods of strong westerly flow and relatively moist environmental conditions in the lower to mid-troposphere contrasted sharply with convection observed during periods of low level easterlies, weak shear, and relatively dry conditions in the mid to upper troposphere. Several examples of mesoscale convection will be shown from the ground (ship)-based and spaceborne radar data during times of TRMM satellite overpasses. Examples of pre-monsoon convection, characterized by isolated cumulonimbus and shallow, precipitating congestus clouds, will also be discussed.

CERES and the S'COOL Project

NASA Technical Reports Server (NTRS)

Chambers, Lin H.; Young, David F.; Barkstrom, Bruce R.; Wielicki, Bruce A.

1997-01-01

The first Clouds and the Earth's Radiant Energy System (CERES) instrument will be launched on the Tropical Rainfall Measuring Mission (TRMM) spacecraft from a Japanese launch site in November 1997. This instrument is a follow-on to the Earth Radiation Budget Experiment (ERBE) begun in the 1980's. The instrument will measure the radiation budget - incoming and outgoing radiant energy - of the Earth. It will establish a baseline and look for climatic trends. The major feature of interest is clouds, which play a very strong role in regulating our climate. CERES will identify clear and cloudy regions and determine cloud physical and microphysical properties using imager data from a companion instrument. Validation efforts for the remote sensing algorithms will be intensive. As one component of the validation, the S'COOL (Students' Cloud Observations On-Line) project will involve school children from around the globe in making ground truth measurements at the time of a CERES overpass. Their observations will be collected at the NASA Langley Distributed Active Archive Center (DAAC) and made available over the Internet for educational purposes as well as for use by the CERES Science Team in validation efforts. Pilot testing of the S'COOL project began in January 1997 with two local schools in Southeastern Virginia and one remote site in Montana. This experience is helping guide the development of the S'COOL project. National testing is planned for April 1997, international testing for July 1997, and global testing for October 1997. In 1998, when the CERES instrument is operational, a global observer network should be in place providing useful information to the scientists and learning opportunities to the students.

Design of bridges against large tectonic deformation

NASA Astrophysics Data System (ADS)

Anastasopoulos, I.; Gazetas, G.; Drosos, V.; Georgarakos, T.; Kourkoulis, R.

2008-12-01

The engineering community has devoted much effort to understanding the response of soil-structure systems to seismic ground motions, but little attention to the effects of an outcropping fault offset. The 1999 earthquakes of Turkey and Taiwan, offering a variety of case histories of structural damage due to faulting, have (re)fueled the interest on the subject. This paper presents a methodology for design of bridges against tectonic deformation. The problem is decoupled in two analysis steps: the first (at the local level) deals with the response of a single pier and its foundation to fault rupture propagating through the soil, and the superstructure is modeled in a simplified manner; and the second (at the global level) investigates detailed models of the superstructure subjected to the support (differential) displacements of Step 1. A parametric study investigates typical models of viaduct and overpass bridges, founded on piles or caissons. Fixed-head piled foundations are shown to be rather vulnerable to faulting-induced deformation. End-bearing piles in particular are unable to survive bedrock offsets exceeding 10 cm. Floating piles perform better, and if combined with hinged pile-to-cap connections, they could survive much larger offsets. Soil resilience is beneficial in reducing pile distress. Caisson foundations are almost invariably successful. Statically-indeterminate superstructures are quite vulnerable, while statically-determinate are insensitive (allowing differential displacements and rotations without suffering any distress). For large-span cantilever-construction bridges, where a statically determinate system is hardly an option, inserting resilient seismic isolation bearings is advantageous as long as ample seating can prevent the deck from falling off the supports. An actual application of the developed method is presented for a major bridge, demonstrating the feasibility of design against tectonic deformation.

Mass balance investigation of alpine glaciers through LANDSAT TM data

NASA Technical Reports Server (NTRS)

Bayr, Klaus J.

1989-01-01

An analysis of LANDSAT Thematic Mapper (TM) data of the Pasterze Glacier and the Kleines Fleisskees in the Austrian Alps was undertaken and compared with meteorological data of nearby weather stations. Alpine or valley glaciers can be used to study regional and worldwide climate changes. Alpine glaciers respond relatively fast to a warming or cooling trend in temperature through an advance or a retreat of the terminus. In addition, the mass balance of the glacier is being affected. Last year two TM scenes of the Pasterze Glacier of Aug. 1984 and Aug. 1986 were used to study the difference in reflectance. This year, in addition to the scenes from last year, one MSS scene of Aug. 1976 and a TM scene from 1988 were examined for both the Pasterze Glacier and the Kleines Fleisskees. During the overpass of the LANDSAT on 6 Aug. 1988 ground truthing on the Pasterze Glacier was undertaken. The results indicate that there was considerable more reflectance in 1976 and 1984 than in 1986 and 1988. The climatological data of the weather stations Sonnblick and Rudolfshuette were examined and compared with the results found through the LANDSAT data. There were relations between the meteorological and LANDSAT data: the average temperature over the last 100 years showed an increase of .4 C, the snowfall was declining during the same time period but the overall precipitation did not reveal any significant change over the same period. With the use of an interactive image analysis computer, the LANDSAT scenes were studied. The terminus of the Pasterze Glacier retreated 348 m and the terminus of the Kleines Fleisskees 121 m since 1965. This approach using LANDSAT MSS and TM digital data in conjunction with meteorological data can be effectively used to monitor regional and worldwide climate changes.

Fusing Cubesat and Landsat 8 data for near-daily mapping of leaf area index at 3 m resolution

NASA Astrophysics Data System (ADS)

McCabe, M.; Houborg, R.

2017-12-01

Constellations of small cubesats are emerging as a relatively inexpensive observational resource with the potential to overcome spatio-temporal constraints of traditional single-sensor satellite missions. With more than 130 compact 3U (i.e., 10 x 10 x 30 cm) cubesats currently in orbit, the company "Planet" has realized near-daily image capture in RGB and the near-infrared (NIR) at 3 m resolution for every location on the earth. However cross-sensor inconsistencies can be a limiting factor, which result from relatively low signal-to-noise ratios, varying overpass times, and sensor-specific spectral response functions. In addition, the sensor radiometric information content is more limited compared to conventional satellite systems such as Landsat. In this study, a synergistic machine-learning framework utilizing Planet, Landsat 8, and MODIS data is developed to produce Landsat 8 consistent LAI with a factor of 10 increase in spatial resolution and a daily observing potential, globally. The Cubist machine-learning technique is used to establish scene-specific links between scale-consistent cubesat RGB+NIR imagery and Landsat 8 LAI. The scheme implements a novel LAI target sampling technique for model training purposes, which accounts for changes in cover conditions over the cubesat and Landsat acquisition timespans. Results over an agricultural region in Saudi Arabia highlight the utility of the approach for detecting high frequency (i.e., near-daily) and fine-scale (i.e., 3 m) intra-field dynamics in LAI with demonstrated potential for timely identification of developing crop risks. The framework maximizes the utility of ultra-high resolution cubesat data for agricultural management and resource efficiency optimization at the precision scale.

Total ozone series at Arosa (Switzerland): Homogenization and data comparison

NASA Astrophysics Data System (ADS)

Staehelin, Johannes; Renaud, Anne; Bader, Jürg; McPeters, Richard; Viatte, Pierre; Hoegger, Bruno; Bugnion, Veronique; Giroud, Marianne; Schill, Herbert

1998-03-01

Five Dobson and two Brewer spectrophotometers were used for total ozone observations at Arosa, beginning in 1926 and providing the world's longest series. In this paper we present the results of our attempts to provide a homogeneous series and discuss the data quality problems of the record. From the mid-1950s to 1992, Dobson instrument D15 was calibrated by the statistical Langley plot method. In 1986 the calibration of another Dobson spectrometer at Arosa (D101) was changed by the intercomparison with the primary world Dobson instrument (D83). A statistical model based on simultaneous measurements of D101 and D15 of the period from 1987 to 1990 was used to obtain a total ozone series in line with the primary Dobson spectrophotometer, including a correction for an optical disalignment problem of D15. The series of Dl0l from 1990 to 1995 was corrected on the basis of data from the Dobson intercomparisons of 1990 and 1995 and comparisons with other total ozone measurements of Brewer and Dobson spectrophotometers at Arosa. A transfer function between Dobson and Brewer spectrophotometric measurements of Arosa is presented, and total ozone measurements of Arosa are compared with version 7 daily overpass data of the satellite instrument the total ozone mapping spectrometer (TOMS) which operated on board Nimbus 7 from autumn 1978 to spring 1993. Available information allowing us to track back the total ozone measurements of Arosa to the measurements of the primary Dobson spectrometer reveal that the total ozone series of Arosa fluctuated no more than approximately 1% against D83 in the period from 1978 to 1995. Average shift of Arosa total ozone data against the TOMS instrument was -1.12 (±0.1)% over the lifetime of the TOMS instrument.

Validation of S-NPP VIIRS Day-Night Band and M Bands Performance Using Ground Reference Targets of Libya 4 and Dome C

NASA Technical Reports Server (NTRS)

Chen, Xuexia; Wu, Aisheng; Xiong, Xiaoxiong; Lei, Ning; Wang, Zhipeng; Chiang, Kwofu

2015-01-01

This paper provides methodologies developed and implemented by the NASA VIIRS Calibration Support Team (VCST) to validate the S-NPP VIIRS Day-Night band (DNB) and M bands calibration performance. The Sensor Data Records produced by the Interface Data Processing Segment (IDPS) and NASA Land Product Evaluation and Algorithm Testing Element (PEATE) are acquired nearly nadir overpass for Libya 4 desert and Dome C snow surfaces. In the past 3.5 years, the modulated relative spectral responses (RSR) change with time and lead to 3.8% increase on the DNB sensed solar irradiance and 0.1% or less increases on the M4-M7 bands. After excluding data before April 5th, 2013, IDPS DNB radiance and reflectance data are consistent with Land PEATE data with 0.6% or less difference for Libya 4 site and 2% or less difference for Dome C site. These difference are caused by inconsistent LUTs and algorithms used in calibration. In Libya 4 site, the SCIAMACHY spectral and modulated RSR derived top of atmosphere (TOA) reflectance are compared with Land PEATE TOA reflectance and they indicate a decrease of 1.2% and 1.3%, respectively. The radiance of Land PEATE DNB are compared with the simulated radiance from aggregated M bands (M4, M5, and M7). These data trends match well with 2% or less difference for Libya 4 site and 4% or less difference for Dome C. This study demonstrate the consistent quality of DNB and M bands calibration for Land PEATE products during operational period and for IDPS products after April 5th, 2013.

Gellan gum-hyaluronic acid spongy-like hydrogels and cells from adipose tissue synergize promoting neoskin vascularization.

PubMed

Cerqueira, Mariana Teixeira; da Silva, Lucília Pereira; Santos, Tírcia Carlos; Pirraco, Rogério Pedro; Correlo, Vítor Manuel; Reis, Rui Luís; Marques, Alexandra Pinto

2014-11-26

Currently available substitutes for skin wound healing often result in the formation of nonfunctional neotissue. Thus, urgent care is still needed to promote an effective and complete regeneration. To meet this need, we proposed the assembling of a construct that takes advantage of cell-adhesive gellan gum-hyaluronic acid (GG-HA) spongy-like hydrogels and a powerful cell-machinery obtained from adipose tissue, human adipose stem cells (hASCs), and microvascular endothelial cells (hAMECs). In addition to a cell-adhesive character, GG-HA spongy-like hydrogels overpass limitations of traditional hydrogels, such as reduced physical stability and limited manipulation, due to improved microstructural arrangement characterized by pore wall thickening and increased mean pore size. The proposed constructs combining cellular mediators of the healing process within the spongy-like hydrogels that intend to recapitulate skin matrix aim to promote neoskin vascularization. Stable and off-the-shelf dried GG-HA polymeric networks, rapidly rehydrated at the time of cell seeding then depicting features of both sponges and hydrogels, enabled the natural cell entrapment/encapsulation and attachment supported by cell-polymer interactions. Upon transplantation into mice full-thickness excisional wounds, GG-HA spongy-like hydrogels absorbed the early inflammatory cell infiltrate and led to the formation of a dense granulation tissue. Consequently, spongy-like hydrogel degradation was observed, and progressive wound closure, re-epithelialization, and matrix remodelling was improved in relation to the control condition. More importantly, GG-HA spongy-like hydrogels promoted a superior neovascularization, which was enhanced in the presence of human hAMECs, also found in the formed neovessels. These observations highlight the successful integration of a valuable matrix and prevascularization cues to target angiogenesis/neovascularization in skin full-thickness excisional wounds.

GPS for structural health monitoring - case study on the Basarab overpass cable-stayed bridge

NASA Astrophysics Data System (ADS)

Lepadatu, Alexandru; Tiberius, Christian

2014-04-01

The Basarab cable-stayed bridge is a newly built structure in Bucharest, Romania, which was inaugurated in June 2011. Before the oficial opening, in order to assure its qualification for trafic, it had to pass several loading tests with convoys of trucks and trams. For this, besides a priori evaluation using the Finite Element Method (FEM), levelling and acceleration measurements were made to identify vertical displacements, as well as vibration frequencies of the bridge. The three-day loading trial of the bridge represented a good opportunity for setting-up a GPS campaign for structural monitoring of the Basarab bridge. Taking advantage of the redundancy obtained via simultaneous multi-sensor measurements, it was possible to compare and validate the GPS estimated displacements with both FEM and levelling. Moreover, the dynamic behaviour of the bridge during a dynamic loading test was evaluated using a 20 Hz GPS observation rate and validated afterwards with vibration frequency estimates from acceleration time series. Along with simulations (FEM) and laboratory tests, the in situ monitoring of a structure has a particular importance in establishing the safety of a newly-built structure. Furthermore, in some cases permanent monitoring is needed for safety and economic reasons, especially for strategic structures such as dams and bridges. GPS technology can satisfy this request due to its real-time processing capability and thus it can be looked upon as a new and promising tool for dynamic evaluation of engineering structures. In this contribution we have also assessed the performance of GPS with regard to accuracy and false alarm probability demands for the continuous monitoring of the Basarab cable-stayed bridge.

Assessment of modal-pushover-based scaling procedure for nonlinear response history analysis of ordinary standard bridges

USGS Publications Warehouse

Kalkan, E.; Kwong, N.

2012-01-01

The earthquake engineering profession is increasingly utilizing nonlinear response history analyses (RHA) to evaluate seismic performance of existing structures and proposed designs of new structures. One of the main ingredients of nonlinear RHA is a set of ground motion records representing the expected hazard environment for the structure. When recorded motions do not exist (as is the case in the central United States) or when high-intensity records are needed (as is the case in San Francisco and Los Angeles), ground motions from other tectonically similar regions need to be selected and scaled. The modal-pushover-based scaling (MPS) procedure was recently developed to determine scale factors for a small number of records such that the scaled records provide accurate and efficient estimates of “true” median structural responses. The adjective “accurate” refers to the discrepancy between the benchmark responses and those computed from the MPS procedure. The adjective “efficient” refers to the record-to-record variability of responses. In this paper, the accuracy and efficiency of the MPS procedure are evaluated by applying it to four types of existing Ordinary Standard bridges typical of reinforced concrete bridge construction in California. These bridges are the single-bent overpass, multi-span bridge, curved bridge, and skew bridge. As compared with benchmark analyses of unscaled records using a larger catalog of ground motions, it is demonstrated that the MPS procedure provided an accurate estimate of the engineering demand parameters (EDPs) accompanied by significantly reduced record-to-record variability of the EDPs. Thus, it is a useful tool for scaling ground motions as input to nonlinear RHAs of Ordinary Standard bridges.

Documentation for assessment of modal pushover-based scaling procedure for nonlinear response history analysis of "ordinary standard" bridges

USGS Publications Warehouse

Kalkan, Erol; Kwong, Neal S.

2010-01-01

The earthquake engineering profession is increasingly utilizing nonlinear response history analyses (RHA) to evaluate seismic performance of existing structures and proposed designs of new structures. One of the main ingredients of nonlinear RHA is a set of ground-motion records representing the expected hazard environment for the structure. When recorded motions do not exist (as is the case for the central United States), or when high-intensity records are needed (as is the case for San Francisco and Los Angeles), ground motions from other tectonically similar regions need to be selected and scaled. The modal-pushover-based scaling (MPS) procedure recently was developed to determine scale factors for a small number of records, such that the scaled records provide accurate and efficient estimates of 'true' median structural responses. The adjective 'accurate' refers to the discrepancy between the benchmark responses and those computed from the MPS procedure. The adjective 'efficient' refers to the record-to-record variability of responses. Herein, the accuracy and efficiency of the MPS procedure are evaluated by applying it to four types of existing 'ordinary standard' bridges typical of reinforced-concrete bridge construction in California. These bridges are the single-bent overpass, multi span bridge, curved-bridge, and skew-bridge. As compared to benchmark analyses of unscaled records using a larger catalog of ground motions, it is demonstrated that the MPS procedure provided an accurate estimate of the engineering demand parameters (EDPs) accompanied by significantly reduced record-to-record variability of the responses. Thus, the MPS procedure is a useful tool for scaling ground motions as input to nonlinear RHAs of 'ordinary standard' bridges.

Retrieval of Spatio-temporal Evaporation by Integrating Landsat OLI Optical and Thermal Data

NASA Astrophysics Data System (ADS)

Wandera, L. N.; Tol, C. V. D.; Mallick, K.; Bayat, B.; Verbeiren, B.; van Griensven, A.; Verhoef, W.; Suliga, J.; Barrios, J. M.; Chormański, J.; Kleniewska, M.

2017-12-01

Soil-Vegetation-Atmosphere (SVAT) Transfer Models are capable of providing continuous predictions of evapotranspiration (ET). However, providing these models with reliable spatio-temporal information of vegetation and soil properties remains challenging. Thus, combining optical and thermal satellite information might assists to overcome this challenge when using SVAT models. In this study, using a radiative transfer model of solar and sky radiation (RTMo), we simulate Landsat 8 reflectance bands (2-7). We then apply a numerical optimization approach to invert the model and retrieve the corresponding canopy attributes leaf chlorophyll content (Cab), leaf water content (Cw), leaf dry matter content (Cdm), leaf brown material (Cs), Leaf Area Index (LAI) and the leaf angle distribution function in the canopy at overpass time. The retrievals are then directly used as inputs into our SVAT model of choice, Soil Canopy Observations of Photochemistry and Energy Fluxes (SCOPE). Using a model for transfer of thermal radiation emitted by vegetation and soil (RTMt), we proceed to simulate Landsat radiance for the corresponding reflectance data using a lookup table (LUT). These variables were then used to develop a crop factor (Kc) map. A reference ET was generated and applied to the Kc map to obtain actual ET. We proceeded to interpolate the ET between the image acquisition dates to have a complete time series. The retrieval maps for the specific variables captured seasonal variability patterns for the respective variables. The generated KC map showed similar trend with the LAI maps. There was an underestimation of actual ET when the simulation was not constrained to the thermal information. The interpolation of ET between acquisition image dates reflected the seasonal trends. Key Word: SVAT, optical, thermal, remote sensing, evapotranspiration

Comparison of Airborne Sunphotometer and Near-Coincident In Situ and Remotely Sensed Water Vapor Measurements during INTEX-ITCT 2004

NASA Astrophysics Data System (ADS)

Livingston, J. M.; Schmid, B.; Redemann, J.; Russell, P.; Ramirez, S.; Eilers, J.; Gore, W.; Howard, S.; Pommier, J.; Bates, T.; Quinn, P.; Chu, D. A.; Gao, B.; Fetzer, E.; McMillan, W.; Seemann, S. W.; Borbas, E.

2005-12-01

The NASA Ames 14-channel Airborne Tracking Sunphotometer (AATS-14) took measurements from aboard a Jetstream 31 (J31) twin turboprop aircraft during 19 science flights (~53 flight hours) over the Gulf of Maine during the period 12 July to 8 August 2004. The flights were conducted in support of the INTEX-NA (INtercontinental chemical Transport EXperiment-North America) and ITCT (Intercontinental Transport and Chemical Transformation of anthropogenic pollution) field studies. AATS-14 measures the solar direct-beam transmission at 14 discrete wavelengths between 354 and 2138 nm, and provides instantaneous measurements of aerosol optical depth (AOD) at 13 wavelengths and water vapor column content, which is derived from measurements at 940 nm and surrounding wavelengths. AATS-14 measurements obtained during aircraft ascents and descents are differentiated to yield vertical profiles of aerosol extinction and water vapor density. Specific J31 flight patterns were designed to address a variety of science goals and, therefore, included a mixture of vertical profiles (spiral and ramped ascents and descents) and constant altitude horizontal transects at a variety of altitudes. In general, flights were designed to include a near sea surface horizontal transect in a region of minimal cloud cover during or near the time of an Aqua and/or Terra satellite overpass, in addition to a low altitude flyby and vertical profile above the NOAA ship Ronald H. Brown. In this paper, we will compare AATS-14 water vapor profiles with simultaneous measurements obtained with a Vaisala humidity sensor on board the J-31 and with spatially and temporally near-coincident data from radiosondes launched from the Ron Brown. AATS-14 data will also be compared with water vapor retrievals from measurements acquired by remote sensors on Aqua and Terra during near-coincident satellite overflights.

Scaling roads and wildlife: The Cinderella principle

USGS Publications Warehouse

Bissonette, J.A.

2002-01-01

It is clear that a reduction in both direct and indirect effects of roads and road networks must be the goal of management agencies. However, increased permeability of roaded landscapes can only be achieved by up-front planning and subsequent mitigative actions. The key is to understand that roads must be made permeable to the movement of animals. More profoundly, ecosystem services, i.e., clean water, clean air, uncontaminated soil, natural landscapes, recreation opportunities, abundant wildlife, and life sustaining ecological processes must not be seriously impacted. In other words, quality of life as measured by ecosystem services should be a major component of the planning process when roads are constructed or improved. Mitigative structures exist to increase permeability of roads. Wildlife overpasses and underpasses, often referred to as ecoducts or green bridges, with associated structures to enable larger animals to exit the road right of way, e.g., earthen escape ramps (BISSONETTE and HAMMER, 2001), various culvert designs for smaller animals including badger pipes and amphibian and reptile tunnels, and fish ladders are but a small sampling of the structures already in place around the world. What is needed is attention to the big picture. Landscapes need to be reconnected and made more permeable. Responsible agencies and organizations need to be aggressive about promoting mitigations and a conservation ethic into road planning. Only with a broad based effort between a concerned public, a database to work from, and a willingness of responsible agencies, will the now very large virtual footprint of roads and road networks be reduced to more closely approximate the physical footprint. By embracing the Cinderella Principle of making the virtual shoe fit more closely the actual physical footprint of roads, we will be able to achieve a closer connection with ecological harmony with its resultant effect of abundant wildlife.

Estimating the Direct Radiative Effect of Absorbing Aerosols Overlying Marine Boundary Layer Clouds in the Southeast Atlantic Using MODIS and CALIOP

NASA Technical Reports Server (NTRS)

Meyer, Kerry; Platnick, Steven; Oreopoulos, Lazaros; Lee, Dongmin

2013-01-01

Absorbing aerosols such as smoke strongly absorb solar radiation, particularly at ultraviolet and visible/near-infrared (VIS/NIR) wavelengths, and their presence above clouds can have considerable implications. It has been previously shown that they have a positive (i.e., warming) direct aerosol radiative effect (DARE) when overlying bright clouds. Additionally, they can cause biased passive instrument satellite retrievals in techniques that rely on VIS/NIR wavelengths for inferring the cloud optical thickness (COT) and effective radius (re) of underlying clouds, which can in turn yield biased above-cloud DARE estimates. Here we investigate Moderate Resolution Imaging Spectroradiometer (MODIS) cloud optical property retrieval biases due to overlying absorbing aerosols observed by Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and examine the impact of these biases on above-cloud DARE estimates. The investigation focuses on a region in the southeast Atlantic Ocean during August and September (2006-2011), where smoke from biomass burning in southern Africa overlies persistent marine boundary layer stratocumulus clouds. Adjusting for above-cloud aerosol attenuation yields increases in the regional mean liquid COT (averaged over all ocean-only liquid clouds) by roughly 6%; mean re increases by roughly 2.6%, almost exclusively due to the COT adjustment in the non-orthogonal retrieval space. It is found that these two biases lead to an underestimate of DARE. For liquid cloud Aqua MODIS pixels with CALIOP-observed above-cloud smoke, the regional mean above-cloud radiative forcing efficiency (DARE per unit aerosol optical depth (AOD)) at time of observation (near local noon for Aqua overpass) increases from 50.9Wm(sup-2)AOD(sup-1) to 65.1Wm(sup-2)AOD(sup -1) when using bias-adjusted instead of nonadjusted MODIS cloud retrievals.

Unmanned Aerial Systems and Spectroscopy for Remote Sensing Applications in Archaeology

NASA Astrophysics Data System (ADS)

Themistocleous, K.; Agapiou, A.; Cuca, B.; Hadjimitsis, D. G.

2015-04-01

Remote sensing has open up new dimensions in archaeological research. Although there has been significant progress in increasing the resolution of space/aerial sensors and image processing, the detection of the crop (and soil marks) formations, which relate to buried archaeological remains, are difficult to detect since these marks may not be visible in the images if observed over different period or at different spatial/spectral resolution. In order to support the improvement of earth observation remote sensing technologies specifically targeting archaeological research, a better understanding of the crop/soil marks formation needs to be studied in detail. In this paper the contribution of both Unmanned Aerial Systems as well ground spectroradiometers is discussed in a variety of examples applied in the eastern Mediterranean region (Cyprus and Greece) as well in Central Europe (Hungary). In- situ spectroradiometric campaigns can be applied for the removal of atmospheric impact to simultaneous satellite overpass images. In addition, as shown in this paper, the systematic collection of ground truth data prior to the satellite/aerial acquisition can be used to detect the optimum temporal and spectral resolution for the detection of stress vegetation related to buried archaeological remains. Moreover, phenological studies of the crops from the area of interest can be simulated to the potential sensors based on their Relative Response Filters and therefore prepare better the satellite-aerial campaigns. Ground data and the use of Unmanned Aerial Systems (UAS) can provide an increased insight for studying the formation of crop and soil marks. New algorithms such as vegetation indices and linear orthogonal equations for the enhancement of crop marks can be developed based on the specific spectral characteristics of the area. As well, UAS can be used for remote sensing applications in order to document, survey and model cultural heritage and archaeological sites.

GreenHouse gas Observations of the Stratosphere and Troposphere (GHOST): Deployment of a Novel Shortwave Infrared Spectrometer On Board the NASA Global Hawk Unmanned Aerial Vehicle

NASA Astrophysics Data System (ADS)

Humpage, N.; Boesch, H.; Palmer, P. I.; Parr-Burman, P.; Vick, A.; Bezawada, N.; Black, M.; Born, A.; Gao, X.; Pearson, D.; Samara-Ratna, P.; Strachan, J.; Wells, M.

2015-12-01

GHOST is a novel, compact shortwave infrared spectrometer, designed for remote sensing of tropospheric columns of greenhouse gases (GHGs) over the ocean from an unmanned aircraft. This is achieved by observing solar radiation at high spectral resolution which has been directly reflected by the ocean surface. The GHOST system has been specifically designed and built to address the following science objectives: 1) testing of atmospheric transport models; 2) validation of GHG column observations over oceans obtained using polar orbiting satellites; and 3) complement in-situ tropopause transition layer observations from other instruments. During January and February 2015 GHOST successfully underwent rigorous environmental testing and was installed on board the Northrop Grumman Global Hawk N872NA, an unmanned aircraft operated by NASA from the Armstrong Flight Research Centre at Edwards Air Force Base, California. Here, we present first results from two Global Hawk flights which took place in March 2015 as part of the CAST-ATTREX campaign. The science flights comprised long, approximately north-south transects over the eastern Pacific Ocean, providing an opportunity to observe spatial trends in GHG column concentrations on regional scale. The second science flight on 10th March 2015 coincided with overpasses from both the NASA OCO-2 (Orbiting Carbon Observatory) and the JAXA GOSAT (Greenhouse gases Observing SATellite) satellites, enabling inter-comparison of the GHOST results with total column observations from both satellites. A TCCON (Total Carbon Column Observing Network) station was also operational at Edwards during the two flights, allowing the GHOST observations to be validated against ground based total column measurements of GHGs.

Angular Normalization of Ground and Satellite Observations of Sun-induced Chlorophyll Fluorescence for Assessing Vegetation Productivity

NASA Astrophysics Data System (ADS)

Chen, J. M.; He, L.; Chou, S.; Ju, W.; Zhang, Y.; Joiner, J.; Liu, J.; Mo, G.

2017-12-01

Sun-induced chlorophyll fluorescence (SIF) measured from plant canopies originates mostly from sunlit leaves. Observations of SIF by satellite sensors, such as GOME-2 and GOSAT, are often made over large view zenith angle ranges, causing large changes in the viewed sunlit leaf fraction across the scanning swath. Although observations made by OCO-2 are near nadir, the observed sunlit leaf fraction could still vary greatly due to changes in the solar zenith angle with latitude and time of overpass. To demonstrate the importance of considering the satellite-target-view geometry in using SIF for assessing vegetation productivity, we conducted multi-angle measurements of SIF using a hyperspectral sensor mounted on an automated rotating system over a rice field near Nanjing, China. A method is developed to separate SIF measurements at each angle into sunlit and shaded leaf components, and an angularly normalized canopy-level SIF is obtained as the weighted sum of sunlit and shaded SIF. This normalized SIF is shown to be a much better proxy of GPP of the rice field measured by an eddy covariance system than the unnormalized SIF observations. The same normalization scheme is also applied to the far-red GOME-2 SIF observations on sunny days, and we found that the normalized SIF is better correlated with model-simulated GPP than the original SIF observations. The coefficient of determination (R2) is improved by 0.07±0.04 on global average using the normalization scheme. The most significant improvement in R2 by 0.09±0.04 is found in deciduous broadleaf forests, where the observed sunlit leaf fraction is highly sensitive to solar zenith angle.

Imaging Spectroscopy Enables Novel Applications and Continuity with the Landsat Record to Sustain Legacy Applications: An Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and Landsat 8 OLI Case Study

NASA Astrophysics Data System (ADS)

Stavros, E. N.; Seidel, F.; Cable, M. L.; Green, R. O.; Freeman, A.

2017-12-01

While, imaging spectrometers offer additional information that provide value added products for applications that are otherwise underserved, there is need to demonstrate their ability to augment the multi-spectral (e.g., Landsat) optical record by both providing more frequent temporal revisit and lengthening the existing record. Here we test the hypothesis that imaging spectroscopic optical data is compatible with multi-spectral data to within ±5% radiometric accuracy, as desirable to continue the long-term Landsat data record. We use a coincident Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) flight with over-passing Operational Land Imager (OLI) data on Landsat 8 to document a procedure for simulating OLI multi-spectral bands from AVIRIS, evaluate influencing factors on the observed radiance, and assess AVIRIS radiometric accuracy compared to OLI. The procedure for simulating OLI data includes spectral convolution, accounting for atmospheric effects introduced by different sensor altitude and viewing geometries, and spatial resampling. After accounting for these influences, we expect the remaining differences between the simulated and the real OLI data result from differences in sensor calibration, surface bi-directional reflectance, from the different viewing geometries, and spatial sampling. The median radiometric percent difference for each band in the data used range from 0.6% to 8.3%. After bias-correction to minimize potential calibration discrepancies, we find no more than 1.2% radiometric percent difference for any OLI band. This analysis therefore successfully demonstrates that imaging spectrometer data can not only address novel applications, but also contribute to the Landsat-type or other multi-spectral data records to sustain legacy applications.

Radiative Susceptibility of Cloudy Atmospheres to Droplet Number Perturbations: 2. Global analysis from MODIS

NASA Technical Reports Server (NTRS)

Oreopoulos, Lazaros; Platnick, Steven

2008-01-01

Global distributions of albedo susceptibility for areas covered by liquid clouds are presented for 4 months in 2005. The susceptibility estimates are based on expanded definitions presented in a companion paper and include relative cloud droplet number concentration (CDNC) changes, perturbations in cloud droplet asymmetry parameter and single-scattering albedo, atmospheric/surface effects, and incorporation of the full solar spectrum. The cloud properties (optical thickness and effective radius) used as input in the susceptibility calculations come from MODIS Terra and Aqua Collection 5 gridded data. Geographical distributions of susceptibility corresponding to absolute ( absolute cloud susceptibility ) and relative ( relative cloud susceptibility ) CDNC changes are markedly different indicating that the detailed nature of the cloud microphysical perturbation is important for determining the radiative forcing associated with the first indirect aerosol effect. However, both types of susceptibility exhibit common characteristics such as significant reductions when perturbations in single-scattering properties are omitted, significant increases when atmospheric absorption and surface albedo effects are ignored, and the tendency to decrease with latitude, to be higher over ocean than over land, and to be statistically similar between the morning and afternoon MODIS overpasses. The satellite-based susceptibility analysis helps elucidate the role of present-day cloud and land surface properties in indirect aerosol forcing responses. Our realistic yet moderate CDNC perturbations yield forcings on the order of 1-2 W/sq m for cloud optical property distributions and land surface spectral albedos observed by MODIS. Since susceptibilities can potentially be computed from model fields, these results have practical application in assessing the reasonableness of model-generated estimates of the aerosol indirect radiative forcing.

First Reprocessing of Southern Hemisphere Additional Ozonesondes (SHADOZ) Ozone Profiles (1998-2016): 2. Comparisons With Satellites and Ground-Based Instruments

NASA Astrophysics Data System (ADS)

Thompson, Anne M.; Witte, Jacquelyn C.; Sterling, Chance; Jordan, Allen; Johnson, Bryan J.; Oltmans, Samuel J.; Fujiwara, Masatomo; Vömel, Holger; Allaart, Marc; Piters, Ankie; Coetzee, Gert J. R.; Posny, Françoise; Corrales, Ernesto; Diaz, Jorge Andres; Félix, Christian; Komala, Ninong; Lai, Nga; Ahn Nguyen, H. T.; Maata, Matakite; Mani, Francis; Zainal, Zamuna; Ogino, Shin-ya; Paredes, Francisco; Penha, Tercio Luiz Bezerra; da Silva, Francisco Raimundo; Sallons-Mitro, Sukarni; Selkirk, Henry B.; Schmidlin, F. J.; Stübi, Rene; Thiongo, Kennedy

2017-12-01

The Southern Hemisphere ADditional OZonesonde (SHADOZ) network was assembled to validate a new generation of ozone-monitoring satellites and to better characterize the vertical structure of tropical ozone in the troposphere and stratosphere. Beginning with nine stations in 1998, more than 7,000 ozone and P-T-U profiles are available from 14 SHADOZ sites that have operated continuously for at least a decade. We analyze ozone profiles from the recently reprocessed SHADOZ data set that is based on adjustments for inconsistencies caused by varying ozonesonde instruments and operating techniques. First, sonde-derived total ozone column amounts are compared to the overpasses from the Earth Probe/Total Ozone Mapping Spectrometer, Ozone Monitoring Instrument, and Ozone Mapping and Profiler Suite satellites that cover 1998-2016. Second, characteristics of the stratospheric and tropospheric columns are examined along with ozone structure in the tropical tropopause layer (TTL). We find that (1) relative to our earlier evaluations of SHADOZ data, in 2003, 2007, and 2012, sonde-satellite total ozone column offsets at 12 stations are 2% or less, a significant improvement; (2) as in prior studies, the 10 tropical SHADOZ stations, defined as within ±19° latitude, display statistically uniform stratospheric column ozone, 229 ± 3.9 DU (Dobson units), and a tropospheric zonal wave-one pattern with a 14 DU mean amplitude; (3) the TTL ozone column, which is also zonally uniform, masks complex vertical structure, and this argues against using satellites for lower stratospheric ozone trends; and (4) reprocessing has led to more uniform stratospheric column amounts across sites and reduced bias in stratospheric profiles. As a consequence, the uncertainty in total column ozone now averages 5%.

Assimilation of the ESA CCI Soil Moisture ACTIVE and PASSIVE Product into the SURFEX Land Surface Model using the Ensemble Transform Kalman Filter

NASA Astrophysics Data System (ADS)

Blyverket, J.; Hamer, P.; Bertino, L.; Lahoz, W. A.

2017-12-01

The European Space Agency Climate Change Initiative for soil moisture (ESA CCI SM) was initiated in 2012 for a period of six years, the objective for this period was to produce the most complete and consistent global soil moisture data record based on both active and passive sensors. The ESA CCI SM products consist of three surface soil moisture datasets: The ACTIVE product and the PASSIVE product were created by fusing scatterometer and radiometer soil moisture data, respectively. The COMBINED product is a blended product based on the former two datasets. In this study we assimilate globally both the ACTIVE and PASSIVE product at a 25 km spatial resolution. The different satellite platforms have different overpass times, an observation is mapped to the hours 00.00, 06.00, 12.00 or 18.00 if it falls within a 3 hour window centred at these times. We use the SURFEX land surface model with the ISBA diffusion scheme for the soil hydrology. For the assimilation routine we apply the Ensemble Transform Kalman Filter (ETKF). The land surface model is driven by perturbed MERRA-2 atmospheric forcing data, which has a temporal resolution of one hour and is mapped to the SURFEX model grid. Bias between the land surface model and the ESA CCI product is removed by cumulative distribution function (CDF) matching. This work is a step towards creating a global root zone soil moisture product from the most comprehensive satellite surface soil moisture product available. As a first step we consider the period from 2010 - 2016. This allows for comparison against other global root zone soil moisture products (SMAP Level 4, which is independent of the ESA CCI SM product).

Impact of High Resolution SST Data on Regional Weather Forecasts

NASA Technical Reports Server (NTRS)

Jedlovec, Gary J.; Case, Jonathon; LaFontaine, Frank; Vazquez, Jorge; Mattocks, Craig

2010-01-01

Past studies have shown that the use of coarse resolution SST products such as from the real-time global (RTG) SST analysis[1] or other coarse resolution once-a-day products do not properly portray the diurnal variability of fluxes of heat and moisture from the ocean that drive the formation of low level clouds and precipitation over the ocean. For example, the use of high resolution MODIS SST composite [2] to initialize the Advanced Research Weather Research and Forecast (WRF) (ARW) [3] has been shown to improve the prediction of sensible weather parameters in coastal regions [4][5}. In an extend study, [6] compared the MODIS SST composite product to the RTG SST analysis and evaluated forecast differences for a 6 month period from March through August 2007 over the Florida coastal regions. In a comparison to buoy data, they found that that the MODIS SST composites reduced the bias and standard deviation over that of the RTG data. These improvements led to significant changes in the initial and forecasted heat fluxes and the resulting surface temperature fields, wind patterns, and cloud distributions. They also showed that the MODIS composite SST product, produced for the Terra and Aqua satellite overpass times, captured a component of the diurnal cycle in SSTs not represented in the RTG or other one-a-day SST analyses. Failure to properly incorporate these effects in the WRF initialization cycle led to temperature biases in the resulting short term forecasts. The forecast impact was limited in some situations however, due to composite product inaccuracies brought about by data latency during periods of long-term cloud cover. This paper focuses on the forecast impact of an enhanced MODIS/AMSR-E composite SST product designed to reduce inaccuracies due data latency in the MODIS only composite product.

Contribution to the development of DOE ARM Climate Modeling Best Estimate Data (CMBE) products: Satellite data over the ARM permanent and AMF sites: Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, B; Dong, X; Xie, S

2012-05-18

To support the LLNL ARM infrastructure team Climate Modeling Best Estimate (CMBE) data development, the University of North Dakota (UND)'s group will provide the LLNL team the NASA CERES and ISCCP satellite retrieved cloud and radiative properties for the periods when they are available over the ARM permanent research sites. The current available datasets, to date, are as follows: the CERES/TERRA during 200003-200812; the CERES/AQUA during 200207-200712; and the ISCCP during 199601-200806. The detailed parameters list below: (1) CERES Shortwave radiative fluxes (net and downwelling); (2) CERES Longwave radiative fluxes (upwelling) - (items 1 & 2 include both all-sky andmore » clear-sky fluxes); (3) CERES Layered clouds (total, high, middle, and low); (4) CERES Cloud thickness; (5) CERES Effective cloud height; (6) CERES cloud microphysical/optical properties; (7) ISCCP optical depth cloud top pressure matrix; (8) ISCCP derived cloud types (r.g., cirrus, stratus, etc.); and (9) ISCCP infrared derived cloud top pressures. (10) The UND group shall apply necessary quality checks to the original CERES and ISCCP data to remove suspicious data points. The temporal resolution for CERES data should be all available satellite overpasses over the ARM sites; for ISCCP data, it should be 3-hourly. The spatial resolution is the closest satellite field of view observations to the ARM surface sites. All the provided satellite data should be in a format that is consistent with the current ARM CMBE dataset so that the satellite data can be easily merged into the CMBE dataset.« less

The 1987 Airborne Antarctic Ozone Experiment: the Nimbus-7 TOMS Data Atlas

NASA Technical Reports Server (NTRS)

Krueger, Arlin J.; Ardanuy, Philip E.; Sechrist, Frank S.; Penn, Lanning M.; Larko, David E.; Doiron, Scott D.; Galimore, Reginald N.

1988-01-01

Total ozone data taken by the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) played a central role in the successful outcome of the 1987 Airborne Antarctic Ozone Experiment. The near-real-time TOMS total ozone observations were suppled within hours of real time to the operations center in Punta Arenas, Chile, over a telecommunications network designed specifically for this purpose. The TOMS data preparation and method of transfer over the telecommunications links are reviewed. This atlas includes a complete set of the near-real-time TOMS orbital overpass data over regions around the Palmer Peninsula of Antarctica for the period of August 8 through September 29, 1987. Also provided are daily polar orthographic projections of TOMS total ozone measurements over the Southern Hemisphere from August through November 1987. In addition, a chronology of the salient points of the experiment, along with some latitudinal cross sections and time series at locations of interest of the TOMS total ozone observations are presented. The TOMS total ozone measurements are evaluated along the flight tracks of each of the ER-2 and DC-8 missions during the experiment. The ozone hole is shown here to develop in a monotonic progression throughout late August and September. The minimum total ozone amount was found on 5 October, when its all-time lowest value of 109 DU is recorded. The hole remains well defined, but fills gradually from mid-October through mid-November. The hole's dissolution is observed here to begin in mid-November, when it elongates and begins to rotate. By the end of November, the south pole is no longer located within the ozone hole.

Monitoring Reservoir Storage in South Asia from Satellite Remote Sensing

NASA Astrophysics Data System (ADS)

Zhang, S.; Gao, H.; Naz, B.

2013-12-01

Realtime reservoir storage information is essential for accurate flood monitoring and prediction in South Asia, where the fatality rate (by area) due to floods is among the highest in the world. However, South Asia is dominated by international river basins where communications among neighboring countries about reservoir storage and management are extremely limited. In this study, we use a suite of NASA satellite observations to achieve high quality estimation of reservoir storage and storage variations at near realtime in South Asia. The monitoring approach employs vegetation indices from the Moderate Resolution Imaging Spectroradiometer (MODIS) 16-day 250 m MOD13Q1 product and the surface elevation data from the Geoscience Laser Altimeter System (GLAS) on board the Ice, Cloud and land Elevation Satellite (ICESat). This approach contains four steps: 1) identifying the reservoirs with ICESat GLAS overpasses and extracting the elevation data for these locations; 2) using the K-means method for water classification from MODIS andapplying a novel post-classification algorithm to enhance water area estimation accuracy; 3) deriving the relationship between the MODIS water surface area and the ICESat elevation; and 4) estimating the storage of reservoirs over time based on the elevation-area relationship and the MODIS water area time series. For evaluation purposes, we compared the satellite-based reservoir storage with gauge observations for 16 reservoirs in South Asia. The storage estimates were highly correlated with observations (R = 0.92 to 0.98), with values for the normalized root mean square error (NRMSE) ranging from 8.7% to 25.2%. Using this approach, storage and storage variations were estimated for 16 South Asia reservoirs from 2000 to 2012.

A Sample of What We Have Learned from A-Train Cloud Measurements

NASA Technical Reports Server (NTRS)

Joiner, Joanna; Vasilkov, Alexander; Ziemke, Jerry; Chandra, Sushil; Spurr, Robert; Bhartia, P. K.; Krotkov, Nick; Sneep, Maarten; Menzel, Paul; Platnick, Steve;

The Goes-R Geostationary Lightning Mapper (GLM): Algorithm and Instrument Status

NASA Technical Reports Server (NTRS)

Goodman, Steven J.; Blakeslee, Richard J.; Koshak, William J.; Mach, Douglas

2010-01-01

The Geostationary Operational Environmental Satellite (GOES-R) is the next series to follow the existing GOES system currently operating over the Western Hemisphere. Superior spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES capabilities include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved capability for the Advanced Baseline Imager (ABI). The Geostationary Lighting Mapper (GLM) will map total lightning activity (in-cloud and cloud-to-ground lighting flashes) continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. In parallel with the instrument development (a prototype and 4 flight models), a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 algorithms, cal/val performance monitoring tools, and new applications. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. A joint field campaign with Brazilian researchers in 2010-2011 will produce concurrent observations from a VHF lightning mapping array, Meteosat multi-band imagery, Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) overpasses, and related ground and in-situ lightning and meteorological measurements in the vicinity of Sao Paulo. These data will provide a new comprehensive proxy data set for algorithm and application development.

Characterization of Dust Properties Near Source Region During ACE-Asia: A Column Satellite-Surface Perspective

NASA Technical Reports Server (NTRS)

Tsay, S. -C.; Ji, Q.; Chu, A.; Hsu, C.; Holben, B.; Campbell, J.; Welton, E. J.; Shu, P. K.

2002-01-01

Many recent field experiments are designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentrations over eastern/southeastern Asia and along the rim of the western Pacific. For example, the ACE-Asia was conducted from March-May 2001 in the vicinity of the Taklimakan and Gobi deserts, East Coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian aerosols is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol physical/optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of aerosol radiative flux in addition to measurements of loading and optical depth. At the time of the Terra/MODIS, SeaWiFS, TOMS and other satellite overpasses, these ground-based observations can provide valuable data to compare with satellite retrievals over land. Preliminary results will be presented and discussed their implications in regional climatic effects.

Dust Aerosols at the Source Region During ACE-ASIA: A Surface/Satellite Perspective

NASA Technical Reports Server (NTRS)

Tsay, Si-Chee; Lau, William K. M. (Technical Monitor)

2001-01-01

ACE (Aerosol Characterization Experiment)-Asia is designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentrations over eastern Asia and along the rim of the western Pacific. The phase-I of ACE-Asia was conducted from March-May 2001 in the vicinity of the Gobi desert, East Coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian dust is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol physical/optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of dust aerosol radiative flux in addition to measurements of loading and optical thickness. At the time of the Terra/MODIS, SeaWiFS, TOMS and other satellite overpasses, these ground-based observations can provide valuable data to compare with satellite retrievals over land. Preliminary results will be presented and discussed their implications in regional climatic effects.

Using the Sonoran and Libyan Desert test sites to monitor the temporal stability of reflective solar bands for Landsat 7 enhanced thematic mapper plus and Terra moderate resolution imaging spectroradiometer sensors

USGS Publications Warehouse

Angal, Amit; Xiong, Xiaoxiong; Choi, Tae-young; Chander, Gyanesh; Wu, Aisheng

2010-01-01

Remote sensing imagery is effective for monitoring environmental and climatic changes because of the extent of the global coverage and long time scale of the observations. Radiometric calibration of remote sensing sensors is essential for quantitative & qualitative science and applications. Pseudo-invariant ground targets have been extensively used to monitor the long-term radiometric calibration stability of remote sensing sensors. This paper focuses on the use of the Sonoran Desert site to monitor the radiometric stability of the Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+) and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. The results are compared with the widely used Libya 4 Desert site in an attempt to evaluate the suitability of the Sonoran Desert site for sensor inter-comparison and calibration stability monitoring. Since the overpass times of ETM+ and MODIS differ by about 30 minutes, the impacts due to different view geometries or test site Bi-directional Reflectance Distribution Function (BRDF) are also presented. In general, the long-term drifts in the visible bands are relatively large compared to the drift in the near-infrared bands of both sensors. The lifetime Top-of-Atmosphere (TOA) reflectance trends from both sensors over 10 years are extremely stable, changing by no more than 0.1% per year (except ETM+ Band 1 and MODIS Band 3) over the two sites used for the study. The use of a semi-empirical BRDF model can reduce the impacts due to view geometries, thus enabling a better estimate of sensor temporal drifts.

Postlaunch Assessment of the Response Versus Scan Angle for the Thermal Emissive Bands of Visible Infrared Imaging Radiometer Suite On-Board the Suomi National Polar-Orbiting Partnership Satellite

NASA Technical Reports Server (NTRS)

Wu, Aisheng; Xiong, Xiaoxiong; Chiang, Kwofu

2017-01-01

The visible infrared imaging radiometer suite (VIIRS) is a key sensor carried on the Suomi national polar-orbiting partnership (S-NPP) satellite, which was launched in October 2011. It has several on-board calibration components, including a solar diffuser and a solar diffuser stability monitor for the reflective solar bands, a V-groove blackbody for the thermal emissive bands (TEB), and a space view port for background subtraction. These on-board calibrators are located at fixed scan angles. The VIIRS response versus scan angle (RVS) was characterized prelaunch in lab ambient conditions and is currently used to characterize the on-orbit response for all scan angles relative to the calibrator scan angle. Since the RVS is vitally important to the quality of calibrated radiance products, several independent studies were performed to analyze the prelaunch RVS measurement data. A spacecraft level pitch maneuver was scheduled during the first 3 months of intensive Cal/Val. The S-NPP pitch maneuver provided a rare opportunity for VIIRS to make observations of deep space over the entire range of Earth view scan angles, which can be used to characterize the TEB RVS. This study provides our analysis of the pitch maneuver data and assessment of the derived TEB RVS by comparison with prelaunch results. In addition, the stability of the RVS after the first 5 years of operation is examined using observed brightness temperatures (BT) over a clear ocean at various angles of incidence (AOI). To reduce the impact of variations in the BT measurements, the daily overpasses collected over the ocean are screened for cloud contamination, normalized to the results obtained at the blackbody AOI, and averaged each year.

Powerful Hurricane Irma Seen in 3D by NASA's CloudSat

NASA Image and Video Library

2017-09-08

NASA's CloudSat satellite flew over Hurricane Irma on Sept. 6, 2017 at 1:45 p.m. EDT (17:45 UTC) as the storm was approaching Puerto Rico in the Atlantic Ocean. Hurricane Irma contained estimated maximum sustained winds of 185 miles per hour (160 knots) with a minimum pressure of 918 millibars. CloudSat transected the eastern edge of Hurricane Irma's eyewall, revealing details of the storm's cloud structure beneath its thick canopy of cirrus clouds. The CloudSat Cloud Profiling Radar excels in detecting the organization and placement of cloud layers beneath a storm's cirrus canopy, which are not readily detected by other satellite sensors. The CloudSat overpass reveals the inner details beneath the cloud tops of this large system; intense areas of convection with moderate to heavy rainfall (deep red and pink colors), cloud-free areas (moats) in between the inner and outer cloud bands of Hurricane Irma and cloud top heights averaging around 9 to 10 miles (15 to 16 kilometers). Lower values of reflectivity (areas of green and blue) denote smaller-sized ice and water particle sizes typically located at the top of a storm system (in the anvil area). The Cloud Profiling Radar loses signal at around 3 miles (5 kilometers) in height (in the melting layer) due to water (ice) particles larger than 0.12 inches (3 millimeters) in diameter. Moderate to heavy rainfall occurs in these areas where signal weakening is detectable. Smaller cumulus and cumulonimbus cloud types are evident as CloudSat moves farther south, beneath the thick cirrus canopy. An animation is available at https://photojournal.jpl.nasa.gov/catalog/PIA21947

A Consistent AVHRR Visible Calibration Record Based on Multiple Methods Applicable for the NOAA Degrading Orbits. Part 2 ; Validation

NASA Technical Reports Server (NTRS)

Doelling, David R.; Bhatt, Rajendra; Scarino, Benjamin R.; Gopalan, Arun; Haney, Conor O.; Minnis, Patrick; Bedka, Kristopher M.

2016-01-01

Consistent cross-sensor Advanced Very High Resolution Radiometer (AVHRR) calibration coefficients are determined using desert, polar ice, and deep convective cloud (DCC) invariant Earth targets. The greatest AVHRR calibration challenge is the slow orbit degradation of the host satellite, which precesses toward a terminator orbit. This issue is solved by characterizing the invariant targets with NOAA-16 AVHRR observed radiances that have been referenced to the Aqua Moderate Resolution Imaging Spectrometer (MODIS) calibration using simultaneous nadir overpass (SNO) observations. Another benefit of the NOAA-16 invariant target-modeled reflectance method is that, because of the similarities among the AVHRR spectral response functions, a smaller spectral band adjustment factor is required than when establishing calibrations relative to a non-AVHRR reference instrument. The sensor- and band-specific calibration uncertainties, with respect to the calibration reference, are, on average, 2 percent and 3 percent for channels 1 and 2, respectively. The uncertainties are smaller for sensors that are in afternoon orbits, have longer records, and spend less time in terminator conditions. The multiple invariant targets referenced to Aqua MODIS (MITRAM) AVHRR calibration coefficients are evaluated for individual target consistency, compared against Aqua MODIS/AVHRR SNOs, and selected published calibration gains. The MITRAM and SNO relative calibration biases mostly agree to within 1 percent for channels 1 and 2, respectively. The individual invariant target and MITRAM sensor relative calibration biases are mostly consistent to within 1 percent and 2 percent for channels 1 and 2, respectively. The differences between the MITRAM and other published calibrations are mostly attributed to the reference instrument calibration differences.

Absolute Calibration of Optical Satellite Sensors Using Libya 4 Pseudo Invariant Calibration Site

NASA Technical Reports Server (NTRS)

Mishra, Nischal; Helder, Dennis; Angal, Amit; Choi, Jason; Xiong, Xiaoxiong

2014-01-01

The objective of this paper is to report the improvements in an empirical absolute calibration model developed at South Dakota State University using Libya 4 (+28.55 deg, +23.39 deg) pseudo invariant calibration site (PICS). The approach was based on use of the Terra MODIS as the radiometer to develop an absolute calibration model for the spectral channels covered by this instrument from visible to shortwave infrared. Earth Observing One (EO-1) Hyperion, with a spectral resolution of 10 nm, was used to extend the model to cover visible and near-infrared regions. A simple Bidirectional Reflectance Distribution function (BRDF) model was generated using Terra Moderate Resolution Imaging Spectroradiometer (MODIS) observations over Libya 4 and the resulting model was validated with nadir data acquired from satellite sensors such as Aqua MODIS and Landsat 7 (L7) Enhanced Thematic Mapper (ETM+). The improvements in the absolute calibration model to account for the BRDF due to off-nadir measurements and annual variations in the atmosphere are summarized. BRDF models due to off-nadir viewing angles have been derived using the measurements from EO-1 Hyperion. In addition to L7 ETM+, measurements from other sensors such as Aqua MODIS, UK-2 Disaster Monitoring Constellation (DMC), ENVISAT Medium Resolution Imaging Spectrometer (MERIS) and Operational Land Imager (OLI) onboard Landsat 8 (L8), which was launched in February 2013, were employed to validate the model. These satellite sensors differ in terms of the width of their spectral bandpasses, overpass time, off-nadir-viewing capabilities, spatial resolution and temporal revisit time, etc. The results demonstrate that the proposed empirical calibration model has accuracy of the order of 3% with an uncertainty of about 2% for the sensors used in the study.

Monitoring and analysis of combustion aerosol emissions from fast moving diesel trains.

PubMed

Burchill, Michael J; Gramotnev, Dmitri K; Gramotnev, Galina; Davison, Brian M; Flegg, Mark B

2011-02-01

In this paper we report the results of the detailed monitoring and analysis of combustion emissions from fast moving diesel trains. A new highly efficient monitoring methodology is proposed based on the measurements of the total number concentration (TNC) of combustion aerosols at a fixed point (on a bridge overpassing the railway) inside the violently mixing zone created by a fast moving train. Applicability conditions for the proposed methodology are presented, discussed and linked to the formation of the stable and uniform mixing zone. In particular, it is demonstrated that if such a mixing zone is formed, the monitoring results are highly consistent, repeatable (with typically negligible statistical errors and dispersion), stable with respect to the external atmospheric turbulence and result in an unusual pattern of the aerosol evolution with two or three distinct TNC maximums. It is also shown that the stability and uniformity of the created mixing zone (as well as the repeatability of the monitoring results) increase with increasing length of the train (with an estimated critical train length of ~10 carriages, at the speed of ~150km/h). The analysis of the obtained evolutionary dependencies of aerosol TNC suggests that the major possible mechanisms responsible for the formation of the distinct concentration maximums are condensation (the second maximum) and thermal fragmentation of solid nanoparticle aggregates (third maximum). The obtained results and the new methodology will be important for monitoring and analysis of combustion emissions from fast moving trains, and for the determination of the impact of rail networks on the atmospheric environment and human exposure to combustion emissions. Copyright © 2010 Elsevier B.V. All rights reserved.

GOSAT validation out standing in the field: A case study of satellite validation using the SSEC Portable Atmospheric Research Center (SPARC)

NASA Astrophysics Data System (ADS)

Wagner, T. J.; Borg, L. A.; Feltz, M.; Gero, P. J.; Knuteson, R. O.; Olson, E.

2016-12-01

The Space Science and Engineering Center (SSEC) at the University of Wisconsin-Madison has developed the SSEC Portable Atmospheric Research Center (SPARC), a mobile 11 m trailer that houses numerous in situ and ground-based remote sensing instruments. Available instrumentation includes the Atmospheric Emitted Radiance Interferometer (AERI), a hyperspectral infrared radiometer from which trace gas concentrations and profiles of temperature and water vapor can be retrieved; the High Spectral Resolution Lidar (HSRL), a multichannel lidar capable of directly retrieving profiles of optical depth and backscatter depolarization; and a Doppler lidar wind profiler. The remote instrumentation suite is complemented by surface meteorology observations and a radiosonde ground station. Collectively, these instruments enable SPARC to participate in a wide variety of field studies, including meteorological field experiments and ground-based satellite calibration and validation studies. In August 2016, SPARC traveled to the Chequamegon National Forest in northern Wisconsin for a two week long deployment alongside the WLEF-TV tower. This 447 m tower houses long-term observations of thermodynamic and atmospheric composition at multiple heights, enabling studies of phenomena like atmospheric/land surface interactions and carbon uptake. During this deployment, SPARC launched radiosondes coincident with clear-sky overpasses of the Greenhouse gases Observing SATellite (GOSAT). Thermodynamic profiles from the radiosondes and AERI combined with the trace gas observations from the tower were used to validate the GOSAT observations of carbon dioxide and methane. The on-site presence of SPARC allowed for better characterization of the environment and greater observational certainty than was possible with the tower alone. Examples from this particular validation study as well as a discussion of how SPARC can contribute to other satellite calibration and validation investigations will be presented.

Hyperspectral Remote Sensing of Terrestrial Ecosystem Productivity from ISS

NASA Astrophysics Data System (ADS)

Huemmrich, K. F.; Campbell, P. K. E.; Gao, B. C.; Flanagan, L. B.; Goulden, M.

2017-12-01

Data from the Hyperspectral Imager for Coastal Ocean (HICO), mounted on the International Space Station (ISS), were used to develop and test algorithms for remotely retrieving ecosystem productivity. The ISS orbit introduces both limitations and opportunities for observing ecosystem dynamics. Twenty six HICO images were used from four study sites representing different vegetation types: grasslands, shrubland, and forest. Gross ecosystem production (GEP) data from eddy covariance were matched with HICO-derived spectra. Multiple algorithms were successful relating spectral reflectance with GEP, including: Spectral Vegetation Indices (SVI), SVI in a light use efficiency model framework, spectral shape characteristics through spectral derivatives and absorption feature analysis, and statistical models leading to Multiband Hyperspectral Indices (MHI) from stepwise regressions and Partial Least Squares Regression (PLSR). Algorithms were able to achieve r2 better than 0.7 for both GEP at the overpass time and daily GEP. These algorithms were successful using a diverse set of observations combining data from multiple years, multiple times during growing season, different times of day, with different view angles, and different vegetation types. The demonstrated robustness of the algorithms presented in this study over these conditions provides some confidence in mapping spatial patterns of GEP, describing variability within fields as well as the regional patterns based only on spectral reflectance information. The ISS orbit provides periods with multiple observations collected at different times of the day within a period of a few days. Diurnal GEP patterns were estimated comparing the half-hourly average GEP from the flux tower against HICO estimates of GEP (r2=0.87) if morning, midday, and afternoon observations were available for average fluxes in the time period.

Evaluating multiple causes of persistent low microwave backscatter from Amazon forests after the 2005 drought

PubMed Central

Hagen, Stephen; Braswell, Bobby; Milliman, Tom; Herrick, Christina; Peterson, Seth; Roberts, Dar; Keller, Michael; Palace, Michael

2017-01-01

Amazonia has experienced large-scale regional droughts that affect forest productivity and biomass stocks. Space-borne remote sensing provides basin-wide data on impacts of meteorological anomalies, an important complement to relatively limited ground observations across the Amazon’s vast and remote humid tropical forests. Morning overpass QuikScat Ku-band microwave backscatter from the forest canopy was anomalously low during the 2005 drought, relative to the full instrument record of 1999–2009, and low morning backscatter persisted for 2006–2009, after which the instrument failed. The persistent low backscatter has been suggested to be indicative of increased forest vulnerability to future drought. To better ascribe the cause of the low post-drought backscatter, we analyzed multiyear, gridded remote sensing data sets of precipitation, land surface temperature, forest cover and forest cover loss, and microwave backscatter over the 2005 drought region in the southwestern Amazon Basin (4°-12°S, 66°-76°W) and in adjacent 8°x10° regions to the north and east. We found moderate to weak correlations with the spatial distribution of persistent low backscatter for variables related to three groups of forest impacts: the 2005 drought itself, loss of forest cover, and warmer and drier dry seasons in the post-drought vs. the pre-drought years. However, these variables explained only about one quarter of the variability in depressed backscatter across the southwestern drought region. Our findings indicate that drought impact is a complex phenomenon and that better understanding can only come from more extensive ground data and/or analysis of frequent, spatially-comprehensive, high-resolution data or imagery before and after droughts. PMID:28873422

CLAAS: the CM SAF cloud property dataset using SEVIRI

NASA Astrophysics Data System (ADS)

Stengel, M.; Kniffka, A.; Meirink, J. F.; Lockhoff, M.; Tan, J.; Hollmann, R.

2013-10-01

An 8 yr record of satellite based cloud properties named CLAAS (CLoud property dAtAset using SEVIRI) is presented, which was derived within the EUMETSAT Satellite Application Facility on Climate Monitoring. The dataset is based on SEVIRI measurements of the Meteosat Second Generation satellites, of which the visible and near-infrared channels were intercalibrated with MODIS. Including latest development components of the two applied state-of-the-art retrieval schemes ensure high accuracy in cloud detection, cloud vertical placement and microphysical cloud properties. These properties were further processed to provide daily to monthly averaged quantities, mean diurnal cycles and monthly histograms. In particular the collected histogram information enhance the insight in spatio-temporal variability of clouds and their properties. Due to the underlying intercalibrated measurement record, the stability of the derived cloud properties is ensured, which is exemplarily demonstrated for three selected cloud variables for the entire SEVIRI disk and a European subregion. All data products and processing levels are introduced and validation results indicated. The sampling uncertainty of the averaged products in CLAAS is minimized due to the high temporal resolution of SEVIRI. This is emphasized by studying the impact of reduced temporal sampling rates taken at typical overpass times of polar-orbiting instruments. In particular cloud optical thickness and cloud water path are very sensitive to the sampling rate, which in our study amounted to systematic deviations of over 10% if only sampled once a day. The CLAAS dataset facilitates many cloud related applications at small spatial scales of a few kilometres and short temporal scales of a few hours. Beyond this, the spatiotemporal characteristics of clouds on diurnal to seasonal, but also on multi-annual scales, can be studied.

CLAAS: the CM SAF cloud property data set using SEVIRI

NASA Astrophysics Data System (ADS)

Stengel, M. S.; Kniffka, A. K.; Meirink, J. F. M.; Lockhoff, M. L.; Tan, J. T.; Hollmann, R. H.

2014-04-01

An 8-year record of satellite-based cloud properties named CLAAS (CLoud property dAtAset using SEVIRI) is presented, which was derived within the EUMETSAT Satellite Application Facility on Climate Monitoring. The data set is based on SEVIRI measurements of the Meteosat Second Generation satellites, of which the visible and near-infrared channels were intercalibrated with MODIS. Applying two state-of-the-art retrieval schemes ensures high accuracy in cloud detection, cloud vertical placement and microphysical cloud properties. These properties were further processed to provide daily to monthly averaged quantities, mean diurnal cycles and monthly histograms. In particular, the per-month histogram information enhances the insight in spatio-temporal variability of clouds and their properties. Due to the underlying intercalibrated measurement record, the stability of the derived cloud properties is ensured, which is exemplarily demonstrated for three selected cloud variables for the entire SEVIRI disc and a European subregion. All data products and processing levels are introduced and validation results indicated. The sampling uncertainty of the averaged products in CLAAS is minimized due to the high temporal resolution of SEVIRI. This is emphasized by studying the impact of reduced temporal sampling rates taken at typical overpass times of polar-orbiting instruments. In particular, cloud optical thickness and cloud water path are very sensitive to the sampling rate, which in our study amounted to systematic deviations of over 10% if only sampled once a day. The CLAAS data set facilitates many cloud related applications at small spatial scales of a few kilometres and short temporal scales of a~few hours. Beyond this, the spatiotemporal characteristics of clouds on diurnal to seasonal, but also on multi-annual scales, can be studied.

A Lagrangian analysis of cold cloud clusters and their life cycles with satellite observations.

PubMed

Esmaili, Rebekah Bradley; Tian, Yudong; Vila, Daniel Alejandro; Kim, Kyu-Myong

2016-10-16

Cloud movement and evolution signify the complex water and energy transport in the atmosphere-ocean-land system. Detecting, clustering, and tracking clouds as semi-coherent cluster objects enables study of their evolution which can complement climate model simulations and enhance satellite retrieval algorithms, where there are large gaps between overpasses. Using an area-overlap cluster tracking algorithm, in this study we examine the trajectories, horizontal extent, and brightness temperature variations of millions of individual cloud clusters over their lifespan, from infrared satellite observations at 30-minute, 4-km resolution, for a period of 11 years. We found that the majority of cold clouds were both small and short-lived and that their frequency and location are influenced by El Niño. More importantly, this large sample of individually tracked clouds shows their horizontal size and temperature evolution. Longer lived clusters tended to achieve their temperature and size maturity milestones at different times, while these stages often occurred simultaneously in shorter lived clusters. On average, clusters with this lag also exhibited a greater rainfall contribution than those where minimum temperature and maximum size stages occurred simultaneously. Furthermore, by examining the diurnal cycle of cluster development over Africa and the Indian subcontinent, we observed differences in the local timing of the maximum occurrence at different life cycle stages. Over land there was a strong diurnal peak in the afternoon while over the ocean there was a semi-diurnal peak composed of longer-lived clusters in the early morning hours and shorter-lived clusters in the afternoon. Building on regional specific work, this study provides a long-term, high-resolution, and global survey of object-based cloud characteristics.

The Heritage of the Operational Usda/nasa Global Reservoir and Lake Monitor

NASA Astrophysics Data System (ADS)

Birkett, C. M.; Beckley, B. D.; Reynolds, C. A.

2012-12-01

Satellite radar altimetry has the ability to monitor variations in surface water height for large lakes and reservoirs. A clear advantage is the provision of data where in situ data are lacking or where there is restricted access to ground-based measurements. A USDA/NASA funded program is performing altimetric monitoring of the largest lakes and reservoirs around the world. The near-real time height measurements are currently derived from NASA/CNES Jason-2/OSTM mission data. Archived data are also utilized from the NASA/CNES Topex/Poseidon and Jason-1 missions, the NRL GFO mission, and the ESA ENVISAT mission. Lake level products are output within 1-2 weeks after satellite overpass, a time delay which will improve to a few days as the project moves into its next phase. The USDA/FAS utilize the products for assessing irrigation potential (and thus crop production estimates), and for general observation of high-water status and short-term drought. Other end-users explore the products to study climate trends, observe anthropogenic effects, and to consider water management and regional security issues. This presentation explores the heritage of the Global Reservoir and Lake Monitor (GRLM) which has its origins in the field of ocean surface topography and the exploration of radar altimetry techniques over non-ocean surfaces. The current system closely follows the software design of the historical NASA Ocean Pathfinder Project and utilizes a global lakes catalogue that was created for climate change/aridity studies. The output of lake level products, imagery and information also echoes an earlier trial (UNDP-funded) lakes database which first offered altimetric products via the world wide web and which enabled world-wide interest to be both assessed and highlighted.;