Abstract:
MODIS/Aqua Sea Ice Extent Daily L3 Global 1km EASE-Grid Day (MYD29P1D) contains the following fields: sea ice by reflectance, sea ice by reflectance spatial quality assurance (QA), ice surface temperature (IST), IST spatial QA, sea ice by IST, and combined sea ice in HDF-EOS format along with corresponding metadata. Data are available from 04 July 2002 to present. Version 4 (V004) is the latest ... version of MYD29P1D data available. The sea ice algorithm uses a Normalized Difference Snow Index (NDSI) modified for sea ice to distinguish sea ice from open ocean based on reflective and thermal characteristics. The only data available for Version 4 (V004) is the Golden Month, which is a sample of V004 data covering the time period 29 August 2002 (day of year 241) through 7 October 2002 (day of year 280). The Golden Month is only available by special request by contacting NSIDC User Services. Please note that NSIDC now has a complete series of Version 5 data, which is the highest version number now available and represents the best quality of data.
Latitude Resolution:
1 km
Longitude Resolution:
1 km
Horizontal Resolution Range:
1 km - < 10 km or approximately .01 degree - < .09 degree
Temporal Resolution:
Daily
Temporal Resolution Range:
Daily - < Weekly
Quality
The quality of MYDP1D daily sea ice maps is greatly improved in Version 4, since the quality was improved with input Version 4 MYD29 data. Validation status is set to provisional until further validation work specific to Aqua IST maps can be completed. Analysis of the quality of the sea ice data products is an ongoing activity. Specific information on the science quality of the sea ice data ... products is reported in the ScienceQualityFlagExplanation object in the CoreMetadata.0 global attribute. The URL for the quality assessment site is given in the product metadata and is linked to from the EOS Data Gateway (EDG) when ordering data. The ScienceQualityFlagExplanation is changed in response to analysis and should be checked for updated information. In the MOD29 and MOD29P1D data products there are two instances of the ScienceQualityFlagExplanation, one for sea ice determined by reflectance data and one for IST written in the metadata. Information on both is posted at that URL. The Ice Surface Temperature PixelQA and the Sea Ice by Reflectance PixelQA data fields provide additional information on algorithm results for each pixel within a spatial context, and are used as a measure of usefulness for sea ice data. QA data are stored as bit flags. QA information is extracted by reading the bits within a byte (See MODIS Sea Ice Quality Assurance Fields). The QA information tells if algorithm results were nominal, abnormal, or if other defined conditions were encountered for a pixel (Riggs, Hall, and Salomonson 2003). See MODIS Land Quality Assessment for further details.
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
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., A. B. Tait, G. A. Riggs, and V. V. Salomonson. 1998. Algorithm Theoretical Basis Document (ATBD) for the MODIS Snow-, Lake Ice- and Sea Ice-Mapping Algorithms (Version 4.0). Electronic version is available online at ... http://snowmelt.gsfc.nasa.gov/MODIS_Snow/atbd.html. Hall, D. K. and J. Martinec. 1985. Remote sensing of ice and snow. London: Chapman and Hall. 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. MODIS Web. MODIS Science and Instrument Team. 2001. http://modis.gsfc.nasa.gov/. Pearson II, F. 1990. Map projections: theory and applications. Boca Raton, FL: CRC Press, Inc. Riggs, G., D. Hall, and V. Salomonson. 2001. MODIS sea ice products user's guide. Electronic version is available online at http://modis-snow-ice.gsfc.nasa.gov/siugkc.html. 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. 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.
