Z. P. Szewczyk
Science Applications International Corporation
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Featured researches published by Z. P. Szewczyk.
Bulletin of the American Meteorological Society | 2005
John E. Harries; Jaqueline E. Russell; J. Hanafin; Helen E. Brindley; Joanna M. Futyan; J. Rufus; S. Kellock; G. Matthews; R. Wrigley; J. Mueller; R. Mossavati; J. Ashmall; Eric C. Sawyer; D. E. Parker; Martin E. Caldwell; P. M. Allan; Adam Smith; M. J. Bates; B. Coan; B. C. Stewart; D. R. Lepine; L. A. Cornwall; D. R. Corney; M. J. Ricketts; D. Drummond; D. Smart; R. Cutler; Siegfried Dewitte; Nicolas Clerbaux; L. Gonzalez
This paper reports on a new satellite sensor, the Geostationary Earth Radiation Budget (GERB) experiment. GERB is designed to make the first measurements of the Earths radiation budget from geostationary orbit. Measurements at high absolute accuracy of the reflected sunlight from the Earth, and the thermal radiation emitted by the Earth are made every 15 min, with a spatial resolution at the subsatellite point of 44.6 km (north–south) by 39.3 km (east–west). With knowledge of the incoming solar constant, this gives the primary forcing and response components of the top-of-atmosphere radiation. The first GERB instrument is an instrument of opportunity on Meteosat-8, a new spin-stabilized spacecraft platform also carrying the Spinning Enhanced Visible and Infrared (SEVIRI) sensor, which is currently positioned over the equator at 3.5°W. This overview of the project includes a description of the instrument design and its preflight and in-flight calibration. An evaluation of the instrument performance after ...
Remote Sensing of Clouds and the Atmosphere VII | 2003
Z. P. Szewczyk
A comparison of shortwave unfiltered radiances measured by CERES instruments operating on two different platforms, TRMM and Terra satellites, is presented. A focus of this paper is twofold: a summary of the recovery of data obtained by the CERES instrument (PFM) failing sensors at the end of its useful life in April and June of 2000, and validation of the recovered data. The data recovery is necessary as deteriorating electronics of the PFM polluted data with cross-talk and noise preventing data processing. It is shown that a pattern recognition is an effective strategy in the data clean-up. The validation is performed by comparing shortwave measurements obtained by the CERES instrument (FM1), on board the Terra satellite, to the recovered PFM data. Comparisons are made for the data collected when orbits of both satellites cross, and viewing geometries of the instruments match.
Optical Science and Technology, SPIE's 48th Annual Meeting | 2003
Kory J. Priestley; Susan Thomas; Peter L. Spence; Z. P. Szewczyk; Edward A. Kizer; Aiman Al-Hajjah; Robert S. Wilson
The CERES Flight Models 1 through 4 instruments were launched aboard NASA’s Earth Observing System (EOS) Terra and Aqua Spacecraft into 705 Km sun-synchronous orbits with 10:30 a.m. and 1:30 p.m. equatorial crossing times. These instruments supplement measurements made by the CERES Proto Flight Model (PFM) instrument launched aboard NASA’s Tropical Rainfall Measuring Mission (TRMM) spacecraft on November 27, 1997 into a 350 Km, 38-degree mid-inclined orbit. An important aspect of the EOS program is the rapid archival and dissemination of datasets measured by EOS instruments to the scientific community. Six months after the commencement of science measurements, CERES is committed to archiving the Edition 1 Level 1 instrument, and Level 2 ERBE-Like data products. These products consist of geolocated and calibrated instantaneous filtered and unfiltered radiances through temporally and spatially averaged TOA fluxes. CERES filtered radiance measurements cover three spectral bands including shortwave (0.3 to 5 μm), total (0.3 to <100 μm) and an atmospheric window channel (8 to 12 μm). The current work summarizes both the philosophy and results of a validation protocol designed to rigorously quantify the quality of the data products as well as the level of agreement between the TRMM, Terra and Aqua datasets.
Remote Sensing | 2005
A. Velázquez Blázquez; Sergio Alonso; A. Bodas-Salcedo; Steven Dewitte; Carlos Domenech; J. Gimeno; John E. Harries; J. Jorge Sanchez; A. Labajo; N. G. Loeb; D. Pino; A. D. Sanchis; G. L. Smith; Z. P. Szewczyk; Ramon Tarruella; J. Torrobella; Ernesto Lopez-Baeza
The purpose of this work is to compare top of the atmosphere (TOA) radiances as measured by the Geostationary Earth Radiation Budget (GERB) instrument on board the METEOSAT-8 (METEOSAT Second Generation) satellite to equivalent independent radiances obtained from radiative transfer simulations performed using surface and atmospheric measured parameters gathered during the GERB Surface Ground Validation Campaign at the Valencia Anchor Station (VAS) reference area in February 2004. In this paper we try to extend the methodology previously developed and tested for the NASA Clouds and the Earths Radiant Energy System (CERES) instrument in the framework of the SEVIRI and GERB Cal/val Area for Large scale field ExperimentS (SCALES) project, to validate GERB much lower spatial resolution data (pixel size of the order of 60 x 60 km2 over the VAS). The study also includes the selection of atmospheric profiles from on-purpose radiosonde and GPS (Global Positioning System) data, a BRDF (Bidirectional Reflectance Distribution Function) estimation for the large-scale study area and Streamer radiative transfer simulations of TOA shortwave and longwave radiances.
Remote Sensing | 2004
Z. P. Szewczyk; George Louis Smith; Kory J. Priestley
A comparison of unfiltered radiances measured by CERES instruments (FM1 and FM4) operating on two different platforms, Terra and Aqua satellites, is presented. Data for the comparison were collected at orbital crossings in July and August 2002. Using a special scanning mode, viewing geometries of the instruments were matched to provide a large data set for comparing all three channels. In addition, the data collected over Greenland were used for a more stringent test of the consistency of the shortwave radiances. Statistics include different scene types and α tests on compiled averages.
Remote Sensing of Clouds and the Atmosphere XX | 2015
Z. P. Szewczyk; G. L. Smith; Kory J. Priestley
The focus of this paper is to introduce a novel strategy for comparison of unfiltered radiances in remote sensing devised for CERES scanners. The strategy is referred to as “matched sites targeting”, in which CERES instruments scan at nadir along their respective collocated ground-tracks. This strategy is enabled by similarities in the Suomi-NPP (FM5) and Aqua (FM3) satellite orbits, and a special scan profile available for the CERES scanners. Comparison of collected data in this strategy is done at a footprint level for a more stringent test of the consistency between the two instruments (FM5 and FM3) for specific scene types, as averages of 330 collocated nadir samples are compared. A comparison of comprehensive “all-sky” measurements is also included as a reference. Results of the unfiltered radiance comparison are based on ES8 or ERBE-like data product using Edition-1 for FM5, and Edition-4 for FM3; cloud coverage is verified using MODIS data available in a SSF product.
Optical Science and Technology, SPIE's 48th Annual Meeting | 2003
Robert Benjamin Lee; G. L. Smith; Z. P. Szewczyk; David P. Kratz; Kory J. Priestley; Susan Thomas; Kathryn A. Bush; Jack Paden; Dhirendra K. Pandey; Robert S. Wilson; Aiman Al-Hajjah
Studies were conducted to define lunar radiances on an absolute radiometric scale tied to the International Temperature Scale of 1990 (ITS-90). The Clouds and the Earths Radiant Energy System (CERES) thermistor bolometer sensor instruments were used to measure lunar radiances from the NASA Tropical Rainfall Measuring Mission (TRMM), Terra, and Aqua spacecraft platforms. Each CERES instrument package consisted of three different sensors: (1) broadband shortwave [0.3 to 5 micrometers]; (2) broadband total [0.3 to >100 micrometers]; and (3) narrowband, water vapor window [8 to 12 micrometers]. Moon-reflected solar radiances were measured with the shortwave sensor while both moon-reflected solar and moon-emitted longwave radiances were measured using the total sensor. The differences between the total and shortwave sensor measurements were used to determine the broadband longwave, moon-emitted radiances. The narrowband, water vapor window sensor measured only the longwave, moon-emitted radiances. The radiances were obtained as a function of phase angle (formed at the moon between directions to the sun and the spacecraft). The resulting filtered radiances were normalized to the mean sun-moon distance, one astronomical unit (AU), and to the mean earth-moon distance of 0.0026 AU (384,400 kilometers). 1998, 2000, and 2001, CERES lunar filtered measurements are presented, compared, and analyzed. Additional measurements are presented from the January 9, 2001, and May 16, 2003, total lunar eclipse events. Analyses of the Clouds and the Earths Radiant Energy System (CERES) thermistor bolometer sensor observations of lunar radiances indicated that broadband shortwave and longwave lunar filtered radiances can be linked to a radiometric scale based upon an International Temperature Scale of 1990 (ITS-90) at absolute levels approaching ± 0.2 Wm-2sr-1. For a lunar image diameter of 31 minutes of arc, an emitting lunar disc temperature of approximately 400 Kelvin was estimated from the longwave radiances near 7-degree phase angle. The integration of the CERES unfiltered radiances over all reflection angles can be used to define the moon radiation budget (MRB).
Proceedings of SPIE, the International Society for Optical Engineering | 2001
Robert Benjamin Lee; G. Louis Smith; Peter L. Spence; Z. P. Szewczyk; Jack Paden; Kory J. Priestley
12 Currently, the moon is being used as a radiometric target to determine on-orbit relative shifts or shifts in the responses of certain spacecraft shortwave sensors. Along these lines, the 1998 Tropical Rainfall Measuring Mission (TRMM) Spacecraft/Clouds and the Earths Radiant Energy System (CERES) thermistor bolometer sensor observations of lunar radiances were analyzed to evaluate the feasibility using the lunar radiances to calibrate the CERES sensor responses. Over a 5 to 110 degree phase angle range, the CERES sensors were used to measure: broadband shortwave (0.3 micrometers to 5.0 micrometers ) moon-reflected solar filtered radiances; broadband total (0.3 micrometers to more than 100 micrometers ) moon- reflected solar and moon-emitted longwave filtered radiances; and narrowband window (8 micrometers to 12 micrometers ) moon- emitted longwave filtered radiances. The TRMM/CERES on-orbit radiance measurements are tied to an International Temperature Scale of 1990 (ITS-90) modeled radiometric scale at uncertainty levels approaching 0.2% (0.2 Wm-2sr-1). Therefore, the TRMM/CERES measurements should be useful in forecasting the precisions of scheduled CERES lunar measurements from the NASA Terra and Aqua Spacecraft platforms near phase angle of 22 and 55 degrees, respectively. The 7-degree phase angle, 1998 CERES shortwave, total, and window measurements yielded lunar filtered radiances of approximately 4.5+/- 0.2, 24.4+/- 0.5, and 4.5+/- 0.2 Wm-2sr-1, respectively. These lunar measurements indicate that broadband shortwave radiances can be characterized at the 5% uncertainty range. The 7-degree, shortwave lunar radiances were found to be approximately 1.5 and 3 times brighter greater the corresponding radiances found at the 22-degree and 55-degree phase angles, respectively. Therefore, the Terra and Aqua CERES lunar shortwave measurements near 22.5- degree and 55-degree phase angles should yield projected precisions in the 7% and 15% range, respectively. The CERES lunar filtered radiance are presented and discussed. Research efforts are outlined briefly for comparing the total sensor broadband and window narrowband longwave lunar radiances during the January 9, 2001 lunar eclipse.
Earth Observing Missions and Sensors: Development, Implementation, and Characterization | 2010
Susan Thomas; Kory J. Priestley; Natividad M. Smith; Norman G. Loeb; Phillip C. Hess; Mohan Shankar; Z. P. Szewczyk; Robert S. Wilson; Denise Cooper
Archive | 2009
Almudena Velazquez Blazquez; Sandra Asensi; Monica Angelats I Coll; Almudena Monsoriu; Carlos Domenech; Victor Estelles; A. Geraldo Ferreira; Kory J. Priestley; G. L. Smith; A. Rius; J. Torrobella; Z. P. Szewczyk; Siegfried Dewitte; Luis Felipe Gonzalez; Ernesto Lopez-Baeza