Summary Results from:

Accuracy assessment of the MODIS 16-day albedo product for snow: comparisons with Greenland in situ measurements
As they relate to the validation of MOD43

Authors: Julienne Stroeve , Jason E. Box, Feng Gao, Shunlin Liang, Anne Nolin, Crystal Schaaf

Source: Remote Sensing of Environment, 94, 46-60, 2005

Link to: Access Publication

Abstract:

The accuracy of the Moderate Resolution Imaging Spectroradiometer (MODIS) 16-day albedo product (MOD43) is assessed using ground-based albedo observations from automatic weather stations (AWS) over spatially homogeneous snow and semihomogeneous ice-covered surfaces on the Greenland ice sheet. Data from 16 AWS locations, spanning the years 20002003, were used for this assessment. In situ reflected shortwave data were corrected for a systematic positive spectral sensitivity bias of between 0.01 and 0.09 on a site-by-site basis using precise optical black radiometer data. Results indicate that the MOD43 albedo product retrieves snow albedo with an average root mean square error (RMSE) of F0.07 as compared to the station measurements, which have F0.035 RMSE uncertainty. If we eliminate all satellite retrievals that rely on the backup algorithm and consider only the highest quality results from the primary bidirectional reflectance distribution function (BRDF) algorithm, the MODIS albedo RMSE is F0.04, slightly larger than the in situ measurement uncertainty. There is general agreement between MODIS and in situ observations for albedo b0.7, while near the upper limit, a 0.05 MODIS albedo bias is evident from the scatter of the 16-site composite.