|U.S. Department of Agriculture
National Agricultural Statistics Service
Research and Development Division
The Vegetation Condition data
selectable below are updated weekly and arranged by two week composite
the 1995 - 1999, 2001-2003, and 2004-2008 (as available) crop
seasons. A water vapor correction was applied by USGS to
data collected by NOAA-14 from the 1995 through the 1999 crop season.
Data from subsequent satellites (NOAA-16, NOAA-17) are not water vapor
corrected. Ratio derived products of a specific period to a previous
date period are only created within images of the same satellite.
The NOAA-16 satellite collected images from the 2001 through 2003 seasons. NOAA-16 started malfunctioning in early 2004, when a scan motor problem caused a 'barcode' appearance. Images from the NOAA-17 satellite replaced NOAA-16 starting in 2004. The USGS released updated calibration coefficients for the NOAA-17 satellite developed by NOAA after the 2004 growing season. Images available below from the 2004 - 2008 growing seasons reflect the updated calibration coefficients. Animations of these images for a given year reveal how the vegetation condition changed during that growing season.