C K. Gatebe & M.D. King, GESTC/UMBC & NASA/GSFC May 28, 2001 1 STATE OF CAR DATA ANALYSIS Charles K....

C K. Gatebe & M.D. King, GESTC/UMBC & NASA/GSFC

May 28, 20011

STATE OF CAR DATA ANALYSISSTATE OF CAR DATA ANALYSIS

Charles K. Gatebe, Michael D. King & Jason Li

Goddard Earth Sciences and Technological Center (GESTC)University of Maryland Baltimore County (UMBC),

Directorate of Earth Sciences, Goddard Space Flight Center & SM&A

Outline

Overview of the Cloud Absorption Radiometer (CAR) State of CAR data analysis

» Quality control and assessment» Calibration» Documentation & Publications

Conclusion and acknowledgments


May 28, 20013

University of Washington CV-580

Solar Spectral Flux

Radiometer (SSFR)

Ames Airborne Tracking

Sunphotometer (AATS)

Cloud Absorption Radiometer

(CAR)


May 28, 20015

Roll: ~20° Time: ~2 min Speed: ~80 m s-1

Height: ~600 m Diameter: ~3 km Resolution

– 10 m (nadir)– 270 m ( = 80°)

Channels– 8 continuously

sampled (0.34-1.37 µm)

– 2 filter wheel channels used for BRDF measurements (1.64 & 2.20 µm)

Bidirectional Reflectance Measurements


May 28, 20016

AccomplishmentAccomplishment

Quality Control and Assessment.» Checked byte packing for 4.5 GB of the CAR data during

SAFARI: Good» Data assessment. This has been done using visuals [(a) &

(b)] created for that purpose. Issues discovered:– Signal dropout in some data scans– Dark-current missing in some scans. A fix has been devised.

» We have computed SNR around nadir view over cloud top, vegetation and Ocean.

Calibration.» Radiometric calibration is complete. Used only the post-

flight calibration to compute coefficients to convert counts to radiance because the pre-flight calibration failed QA/QC criteria.

» Angular sensitivity measurements have been done and will be applied to the final calibration.

» Spectral calibration has also be done and will be applied to the final calibration.


May 28, 20017

AccomplishmentAccomplishment

Calibration contd.» Level-1B data has been processed for the first four

flights. We plan to complete processing no later than December, 2001. Note that this product won’t have atmospheric correction; planned for the future.

Documentation.» We contributed to the Univ. Washington SAFARI-2000

data report.» CAR write-up and schematics are complete. This

material will be available on our new web site: http://car.gsfc.nasa.gov/ (not activated yet. But visit: http://modis-atmos.gsfc.gov/car/index.html).

» Updated CAR write-up in a book on remote sensing by Herbert Kramer.


May 28, 20018

To be accomplishedTo be accomplished

Publications based on.» Spectral variability of directional reflectance of

several natural surfaces and ecosystem: Mopane trees, white pans (Sua and Etosha), “red” sand in Kuiseb desert, and Sc off-Namibian coastline.

» Use CAR radiance to compute spectral albedo of the natural surfaces and ecosystem mentioned above. Could compare our values with estimates from other instruments e.g. AirMISR, and SSFR and with radiative transfer simulations.

» Compare CAR, MAS, and AirMISR radiance measurements over the co-located sites.

» Radiative transfer models will be tested with CAR near-instantaneous radiation field measurements and parameters that determine the radiation field (e.g. clouds, aerosol, trace gases, etc.) obtained by other instruments aboard the CV-580.


May 28, 20019

Kruger Kruger National National

ParkPark

Skukuza

Sowa Pan

Maun

Mongu

NamiNamib b

DesertDesert

Skeleton Coast

Etosha Pan

OkavangOkavangoo

DeltaDelta


May 28, 200110

Conclusion Conclusion

The state of data analysis:– We have done a comprehensive QC/QA on all our data. We

have determined that data are available for all the 23 flights missions between August 15 and September 16.

– We have documented all the missions and information is available on the University of Washington web site. It will also be available in our web site.

– We are in the process of calibrating our data into Level -1B and plan to complete it by December, 2001.

A publication titled: Airborne spectral measurements of surface-atmosphere anisotropy for different natural surfaces and ecosystem over southern Africa, is in progress.

Data request. Write to: [email protected] & gatebe@climate. gsfc.nasa.gov.


May 28, 200111

Acknowledgments

Persons:– Colleagues: Tom Arnold,

Drs. Steve Platnick and Si-Chee Tsay

– Peter Shu and team– Prof. Peter Hobbs and

team– Prof. Harold Annegarn/Drs.

Tim Suttles and Bob Swap and team

– Families

Institutions:– NASA’s EOS Project – GEST Center/UMBC– University of Washington,

Seattle.– University of Wits.– Govts. of Botswana,

Mozambique Namibia, South Africa, Zambia

C K. Gatebe & M.D. King, GESTC/UMBC & NASA/GSFC May 28, 2001 1 STATE OF CAR DATA ANALYSIS Charles K....

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