May 1, 2005

The algorithm for generating the spatially complete albedo products has been substantially revised to provide better trends in regions with limited temporal coverage. These upgrades include checking to make sure temporal statistical trends in high latitudes are correct and incorporating five-year MOD43B3 climatology data into single year processing in snow impacted and persistently cloudy regions.

The new algorithm has been applied to five years of collection 4 MOD43B3 data (2000 through 2004) to provide the community with five years of spatially complete albedo products. In addition, high quality retrievals from five years of collection 4 MOD43B3 data were aggregated for each 16-day period. The temporal interpolation technique was then applied to this aggregated data to produce a spatially complete five-year aggregate climatology. The five single years of spatially complete data are intended to provide researchers with inter-annual variability, whereas the five-year aggregate climatology will provide average conditions that can be applied to any year of processing.

The first three 16-day periods of the 2000 data is not available as the Terra satellite was not operational. In order to process this data, the five-year MOD43B3 climatology was substituted for these three 16-day periods.

The spatially complete five-year aggregate data and the 2002 single year data are currently on the anonymous modis-atmos.gsfc.nasa.gov ftp site. For this processing, the version is designated as c004.v2.0, with the c004 in reference to collection 4 of MOD43B3, and v2.0 representing the updated algorithm. The single year data are being uploaded as processing completes (all years should be posted by the end of May). For each single year or climatology, uploaded data includes spatially complete albedo maps, MOD43B3 general and band specific Quality Assurance (QA), processing QA, statistics of the spatially complete maps by ecosystem class and for various resolutions, and visualizations of the spatially complete maps.

September 5, 2004

The 2002 V004 albedo map and statistical products are available for download from the ftp site. This data have several advantages over the 2001 V003 data, including upgrades in both the MOD43B3 and spatial filing algorithms. In addition, the 2002 MOD43B3 data is temporally complete whereas the 2001 MOD43B3 data was missing two 16-day periods in June due to MODIS being non-operational.

The product is stored in the normal HDF files (v1.0) and internally compressed HDF files (v1.2). The compressed files dramatically reduce the data volume, however they also incur a significant I/O cost especially when performing iterative reads (i.e. repeatedly reading latitude belts or partial maps). This is due to the entire map being decompressed every time a section of the map is read.

Current plans are to process, and make available, the collection 5 Albedo data for multiple years during the 2005 calendar year.

April 13, 2004

The 2001 V003 albedo map and statistical products released in December 2003 did not contain the three broadband channels, 0.3-0.7µm, 0.3-5.0µm and 0.7-5.0µm. This was due to there not being broadband specific quality assurance information which resulted in outliers adversely affecting the phenological fitting technique. A methodology for processing broadband channels was developed in March 2004 and the reprocessed 2001 V003 data set now includes the broadband data.

As of April 13th, 2004, the 2001 V003 1-minute broadband albedo maps are available for download from the ftp site, and the 2001 V003 statistical product has been updated to include the broadband values in the HDF files. The 2001 V003 statistical products with the broadband products are designated as v1.1, whereas the statistical products without the broadband products are designated as v1.0.