Short Name:
MCD43D18

MODIS/Terra+Aqua BRDF/Albedo Parameter3 Band6 Daily L3 Global 30ArcSec CMG V006

The MCD43D18 Version 6 Bidirectional Reflectance Distribution Function and Albedo (BRDF/Albedo) Model Parameter data set is a daily 16-day product. This product incorporates the Climate Modeling Grid (CMG) structure in which each file geographically covers the entire earth rather than the 10 degree x 10 degree latitude and longitude tiling system utilized by the standard MODIS land products. Unlike the standard CMG pixel resolution of 5600 meters the MCD43D products are 1000 meters, consequently, because of the large file size each product contains just one layer. The Julian date in the granule ID of each specific file represents the 9th day of the 16 day composite period, and consequently the observations are weighted to estimate the BRDF/Albedo for that day. The layer in the MCD43D18 is the Bidirectional Reflectance Distribution Function geometric parameter for MODIS band 6. This geometric parameter, in conjunction with the isotropic and volumetric parameters, is used to derive the Albedo and BRDF value for MODIS band 6. The MODIS BRDF/ALBEDO products have achieved stage 3 validation. Users are urged to use the band specific quality flags to isolate the highest quality full inversion results for their own science applications (https://www.umb.edu/spectralmass/terra_aqua_modis/v006). Improvements/Changes from Previous Versions * Observations are weighted to estimate the BRDF/Albedo on the ninth day of the 16-day period. * MCD43 products use the snow status weighted to the ninth day instead of the majority snow/no-snow observations from the 16-day period. * Better quality at high latitudes from use of all available observations for the acquisition period. Collection 5 used only four observations per day. * The MCD43 products use L2G-lite surface reflectance as input. * When there are insufficient high quality reflectances, a database with archetypal BRDF parameters is used to supplement the observational data and perform a lower quality magnitude inversion. This database is continually updated with the latest full inversion retrieval for each pixel. * CMG Albedo is estimated using all the clear-sky observations within the 1,000 m grid for MCD43D as opposed to aggregating from the 500 m albedo. Important Quality Information The incorrect representation of the aerosol quantities (low average high) in the C6 MYD09 and MOD09 surface reflectance products may have impacted down stream products particularly over arid bright surfaces (https://landweb.modaps.eosdis.nasa.gov/cgi-bin/QA_WWW/displayCase.cgi?esdt=MOD09&caseNum=PM_MOD09_20010&caseLocation=cases_data&type=C6). This (and a few other issues) have been corrected for C6.1. Therefore users should avoid substantive use of the C6 MCD43 products and wait for the C6.1 products. In any event, users are always strongly encouraged to download and use the extensive QA data provided in MCD43A2, in addition to the briefer mandatory QAs provided as part of the MCD43A1, 3, and 4 products.

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