Relative Greenness (RG) ranges from 0-100% and indicates how green each 500-m square pixel of land is in relation to a 10-year historical (2003-2012) database of greenness values for that particular pixel. An RG value of 100% signifies that this is the highest greenness level ever reached during the multi-year period, while an RG value of 0% indicates that this is the lowest greenness level reached over that same period. RG is calculated daily from the past 7 days of MODIS satellite imagery using NDVI (Normalized Difference Vegetation Index). The calculation also involves a smoothing routine to filter out unrealistic daily rises and drops in greenness. If a given pixel is cloudy during the entire weekly period, the RG value used is taken from the last available valid value for that pixel. RG is a very important variable in the fire danger model used in OK-FIRE. It is used to model live fuel moisture (herbaceous and woody) and to apportion the fuel load distribution between 1-hour dead fuels and live herbaceous and live deciduous woody fuels. This map is updated daily when the daily MODIS satellite data is processed.
120 David L. Boren Blvd., Suite 2900
Norman, OK 73072