1. Daily BRDF/Albedo Algorithm for MODIS Direct Broadcast Sites Crystal Schaaf(1), Alan Strahler(1), Curtis Woodcock(1), Yanmin Shuai(1), Jicheng Liu(1), Ziti Jiao(1), Qingling Zhang(1), John Hodges(1), Jonathan Salomon(1), Xiaowen Li(1,2,3), Jindi Wang(3), David Roy(4), Ian Grant(5), David Jupp(6), Phillip Frost(7), Tom Bobbe(8), Robert Wolfe(9) (1) Department of Geography and Center for Remote Sensing, Boston University, Boston, MA 02215, USA; (2) Institute of Remote Sensing Applications/CAS; (3) Beijing Normal University; (4) South Dakota State University; (5) Commonwealth Bureau of Meterology; (6) CSIRO; (7) Council for Scientific and Industrial Research (CSIR) Satellite Application Centre (SAC); (8) USDA Forest Service Remote Sensing Applications Center (RSAC); (9) Goddard Space Flight Center The initial implementation over sites in China (Institute of Remote Sensing Applications) will be followed by sites in Australia (CSIRO and the Bureau of Meteorology), South Africa (Council for Scientific and Industrial Research Satellite Application Centre), and the USA (USDA Forest Service Remote Sensing Applications Center, Utah). Below, daily rolling albedos of an agricultural site on the North China Plain are monitored during a senescent period in 2004. Standard MODIS BRDF/Albedo Products are available globally from March 2000 to present and include BRDF Model Parameters, Black-sky and White-sky Albedos, and Nadir BRDF-Adjusted Reflectances (NBAR). These products are currently provided at a 1km resolution every 16 days and are based on multi-date, cloud- free, atmospherically-corrected multi-spectral surface reflectances fit to a linear kernel-driven BRDF model. The overall global quality has increased in successive reprocessing efforts with improved atmospheric correction, and cloud detection and the use of MODIS observations from both Aqua and Terra. Based on experience with this operational algorithm, a daily rolling, gridded, 500m Bidirectional Reflectance Distribution Function (BRDF) and albedo algorithm is being developed for Direct Broadcast sites. Such an algorithm is of interest to the Direct Broadcast community as it will allow (1) the production of daily characterizations of the surface anisotropy via the retrieval of the BRDF, (2) the use of these daily BRDFs to correct for view angle effects and produce surface reflectances at a common, nadir-view geometry; (3) the subsequent use of these daily Nadir BRDF-Adjusted Reflectances (NBAR) for vegetation indexes, land cover classification, and phenological monitoring of the vegetation cycle; (4) local implementation of the burned area detection algorithm and (5) the production of daily surface albedos. As the MODIS algorithm relies on multi-day observations, the efforts includes the development of a gridding and binning routine to standardize the accumulation of data for BRDF retrieval across various Direct Broadcast sites. Retrieval constraints can be tuned both temporally and spatially for timely regional applications. 0.0 0.3+ NIR (0.10-0.45) Red (0.0-0.1) Green (0.0-0.15) Differences between MODIS surface reflectances from adjoining swaths (upper left) and MODIS NBAR (upper right) over the Great Lakes/NYarea, 6 Sep 2000. Swath effects can still be seen in conventional NDVI computation (lower left), but have been removed in the NBAR-NDVI (lower right). 0.0 1.0 Pixel 1656, 1591 Despite frequent cloudy episodes in the second half of the period, the overall phenology of the area is captured. Red BSA NIR BSA (NIR-Red)/(NIR+Red)