The MODIS/Aqua Snow Cover Monthly L3 Global 0.05Deg CMG (MYD10CM) data set, new for Version 5 (V005), contains snow cover and Quality Assessment (QA) data in Hierarchical Data Format- Earth Observing System (HDF-EOS) format, and corresponding metadata. This data set consists of 7200 column by 3600 row global arrays of snow cover in a 0.05 deg Climate Modeling Grid (CMG). MODIS snow cover data are based on a snow mapping algorithm that employs a Normalized Difference Snow Index (NDSI) and other criteria tests. Monthly average snow cover is calculated from the daily global products for the month. 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 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, Snow Cover; and the Snow ... Spatial QA field. These quality indicators are generated during production or in post-production scientific and quality checks of the data product. 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.
NASA Goddard Space Flight Center (GSFC)
Science Systems and Applications, Inc.
Province or State:
Earth Science Data and Information System (ESDIS). 1996. EOS Ground System (EGS) systems and operations concept. Greenbelt, MD: Goddard Space Flight Center.
Hall, D. 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, D. ... K., Jeffrey R. Key, Kimberly A. Casey, George A. Riggs, and Donald Cavalieri. May 2004. Sea ice surface temperature product from MODIS. IEEE Transactions on Geoscience and Remote Sensing 42:5.
Hall, D. K. and J. Martinec. 1985. Remote sensing of ice and snow. London: Chapman and Hall.
Hall, D. K., G. A. Riggs, and V. V. Salomonson. 1995. Development of methods for mapping global snow cover using Moderate Resolution Imaging Spectroradiometer (MODIS). Remote Sensing of the Environment 54(2):127-140.
Hall, D. K., G. A. Riggs, and V. V. Salomonson. September 2001. Algorithm Theoretical Basis Document (ATBD) for the MODIS Snow-, Lake Ice- and Sea Ice-Mapping Algorithms. Greenbelt, MD: Goddard Space Flight Center.
Hapke, B. 1993. Theory of reflectance and emittance spectroscopy. Cambridge: Cambridge University Press.
Key, J. R., J. B. Collins, C. Fowler, and R. S. Stone. 1997. High latitude surface temperature estimates From thermal satellite data. Remote Sensing of the Environment 61:302-309.
Key, J. R., J. A. Maslanik, T. Papakyriakou, M. C. Serreze, and A. J. Schweiger. 1994. On the validation of satellite-derived sea ice surface temperature. Arctic 47:280-287.
Markham, B.L. and J.L. Barker. 1986. Landsat MSS and TM post-calibration dynamic ranges, exoatmospheric reflectances and at-satellite temperatures. EOSAT Technical Notes 1:3-8.
MODIS Characterization and 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, G. A., D. K. Hall, and V. V. Salomonson. February 2003. MODIS sea ice products user guide.
Riggs, G. A., D. K. Hall, and S. A. Ackerman. 1999. Sea ice extent and classification mapping with the Moderate Resolution Imaging Spectroradiometer Airborne Simulator. Remote Sensing of the Environment 68:152-163.
Scambos, Ted A., Terry M. Haran, and Robert Massom. In press. Validation of AVHRR and MODIS Ice Surface Temperature Products Using In Situ Radiometers. Annals of Glaciology 44.
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.