Abstract:
The MODIS/Aqua Snow Cover 8-Day L3 Global 500m Grid (MYD10A2) data set contains data fields for maximum snow cover extent over an eight-day compositing period and a chronology of snow occurrence observations in compressed Hierarchical Data Format-Earth Observing System (HDF-EOS) format, along with corresponding metadata. MOD10A2 consists of 1200 km by 1200 km tiles of 500 m resolution data gridded ... in a sinusoidal map projection. The Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover data are based on a snow mapping algorithm that employs a Normalized Difference Snow Index (NDSI) and other criteria tests. Data are stored in HDF-EOS format, and are available from 04 July 2002 to present via FTP. Data can also be obtained in GeoTIFF format by ordering the data through the Data Pool.
Quality
Quality indicators for MODIS snow data can be found in the following places: * AutomaticQualityFlag and the ScienceQualityFlag metadata objects and their corresponding explanations: AutomaticQualityFlagExplanation and ScienceQualityFlagExplanation located in the CoreMetadata.0 global attributes ... * Custom local attributes associated with each Scientific Data Set, for example, Maximum Snow Extent. These quality indicators are generated during production or in post-production scientific and quality checks of the data product. For more information on local and global attributes, go to one of the following documents: * MOD10A2 and MYD10A2 Local Snow Cover Attributes, Version 5 * MOD10A2 and MYD10A2 Global Snow Cover Attributes, Version 5 The AutomaticQualityFlag is automatically set according to conditions for meeting data criteria in the snow mapping algorithm. In most cases, the flag is set to either Passed or Suspect, and in rare instances it may be set to Failed. Suspect means that a significant percentage of the data were anomalous and that further analysis should be done to determine the source of anomalies. The AutomaticQualityFlagExplanation contains a brief message explaining the reason for the setting of the AutomaticQualityFlag. The ScienceQualityFlag and the ScienceQualityFlagExplanation are set after production, either after an automated QA program is run or after the data product is inspected by a qualified snow scientist. Content and explanation of this flag are dynamic so it should always be examined if present. The algorithm tests for a variety of anomalous conditions and sets the pixel value accordingly if such conditions are detected. Summary statistics about missing data, the percent cloud cover, the percent of good or other quality data, and snow cover percent are calculated and placed in the metadata for each product. The NASA Goddard Space Flight Center: MODIS Land Quality Assessment Web site provides updated quality information for each product.
DOROTHY
K.
HALL Role:
INVESTIGATOR
Contact Address:
National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC)
Mail stop 614.1 City:
Greenbelt
Province or State:
MD
Postal Code:
20771
VINCE
V.
SALOMONSON Role:
INVESTIGATOR
Phone:
801-585-9492
Email:
vincent.salomonson at utah.edu
Contact Address:
University of Utah
Department of Meteorology
135 S 1460 E, Rm 809 City:
Salt Lake City
Province or State:
UT
Postal Code:
84112
Country:
US
GEORGE
A.
RIGGS Role:
INVESTIGATOR
Phone:
301-614-5650
Email:
George.A.Riggs at nasa.gov
Contact Address:
NASA Goddard Space Flight Center (GSFC)
Science Systems and Applications, Inc.
Code 614.1 City:
Greenbelt
Province or State:
MD
Postal Code:
20771
Country:
USA
NSIDC
USER SERVICES Role:
TECHNICAL CONTACT
Phone:
+1 (303) 492-6199
Fax:
+1 (303) 492-2468
Email:
nsidc at nsidc.org
Contact Address:
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado City:
Boulder
Province or State:
CO
Postal Code:
80309-0449
Country:
USA
Publications/References
Diner, D. J., J. V. Martonchik, C. Borel, S. A. W. Gerstl, H. R. Gordon, Y. Knyazikhin, R. Myneni, B. Pinty, and M. M. Verstraete. 1999. MISR Level-2 Surface Retrieval Algorithm Theoretical Basis Document. Pasadena, CA: Jet Propulsion Laboratory.
Earth Science Data and Information System (ESDIS). 1996. EOS Ground System (EGS) Systems and Operations Concept. Greenbelt, MD: Goddard Space Flight ... Center.
Hall, Dorothy K., George A. Riggs, and Vincent V. Salomonson. September 2001a. Algorithm Theoretical Basis Document (ATBD) for the MODIS Snow-, Lake Ice- and Sea Ice-Mapping Algorithms. Greenbelt, MD: Goddard Space Flight Center.
Hall, Dorothy K. and J. Martinec. 1985. Remote Sensing of Ice and Snow. London: Chapman and Hall.
Hall, Dorothy K., J. L. Foster, D. L. Verbyla, A. G. Klein, and C. S. Benson. 1998. Assessment of Snow Cover Mapping Accuracy in a Variety of Vegetation Cover Densities in Central Alaska. Remote Sensing of the Environment 66:129-137.
Hall, Dorothy K., J. L. Foster, Vincent V. Salomonson, A. G. Klein, and J. Y. L. Chien. 2001b. Development of a Technique to Assess Snow-Cover Mapping Accuracy from Space. IEEE Transactions on Geoscience and Remote Sensing 39(2):232-238.
Hall, Dorothy K., George A. Riggs. 2006. Assessment of Errors in the MODIS Suite of Snow-Cover Products. Hydrological Processes.
Hapke, B. 1993. Theory of Reflectance and Emittance Spectroscopy. Cambridge: Cambridge University Press. Klein, A. MODIS Snow Albedo Prototype. 2003.
Klein, A. G. and Julienne Stroeve. 2002. Development and Validation of a Snow Albedo Algorithm for the MODIS Instrument. Annals of Glaciology 34:45-52.
Klein, A. G., Dorothy K. Hall, and George A. Riggs. 1998. Improving Snow-Cover Mapping in Forests Through the Use of a Canopy Reflectance Model. Hydrologic Processes 12(10-11):1723-1744.
Markham, B. L. and J. L. Barker. 1986. Landsat Multispectral Scanner (MSS) and Thematic Mapper (TM) Post-Calibration Dynamic Ranges, Exoatmospheric Reflectances and At-Satellite Temperatur es. EOSAT Technical Notes 1:3-8.
MODIS Characterization Support Team (MCST). 2000. MODIS Level-1B Product User's Guide for Level-1B Version 2.3.x Release 2. MCST Document #MCM-PUG-01-U-DNCN.
Pearson II, F. 1990. Map Projections: Theory and Applications. Boca Raton, FL: CRC Press, Inc.
Riggs, George A., Dorothy K. Hall, and Vincent V. Salomonson. January 2006. MODIS Snow Products User Guide for Collection 4 Data Products. United States Geological Survey. 'Sinusoidal Equal Area.' Map Projections. 2003. http://egsc.usgs.gov/isb/pubs/MapProjections/projections.html#sinus....
Wiscombe, W. J. and S. G. Warren. 1980. A Model for the Spectral Albedo of Snow I: Pure Snow. Journal of the Atmospheric Sciences 37:2712-2733.
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