Top Right:  This subset from the lower central portion of the top-left image, highlights Lago de Chapala between the states of Jalisco and Michoacan.  Covering approximately 1100 km², it is Mexico's largest freshwater lake.

•  Reduced file volume:  internal compression
•  Improved aerosol retrieval

Product Description
The MODIS Surface Reflectance products provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric scattering or absorption.  Low-level data are corrected for atmospheric gases and aerosols, yielding a level-2 basis for several higher-order gridded level-2 (L2G) and level-3 products.

MOD09A1 provides Bands 1-7 at 500-meter resolution in an 8-day gridded level-3 product in the Sinusoidal projection.  Each MOD09A1 pixel contains the best possible L2G observation during an 8-day period as selected on the basis of high observation coverage, low view angle, the absence of clouds or cloud shadow, and aerosol loading.  Science Data Sets provided for this product include reflectance values for Bands 1-7, quality assessment, and the day of the year for the pixel along with solar, view, and zenith angles.  

Version-5 MODIS/Terra Surface Reflectance products are Validated Stage 1, meaning that accuracy has been estimated using a small number of independent measurements obtained from selected locations and time periods and ground-truth/field program efforts. Although there may be later improved versions, these data are ready for use in scientific publications.