Relative Greenness

Idabel Broken Bow Mt. Herman Wister Talihina Clayton Cloudy Hugo Antlers Lane Durant Wilburton Stigler Sallisaw Webbers Falls Cookson Westville Tahlequah Eufaula McAlester Stuart Centrahoma Tishomingo Holdenville Madill Burneyville Ardmore Newport Fittstown Sulphur Haskell Porter Okmulgee Inola Bixby Tulsa Okemah Bowlegs Ada Byars Pauls Valley Ringling Hectorville Bristow Shawnee Ketchum Ranch Washington Norman Chandler Spencer OKC East OKC North Waurika Ninnekah Chickasha Acme Oilton Minco Guthrie Walters Apache Grandfield Medicine Park Fort Cobb Tipton Altus Hobart El Reno Hinton Perkins Marena Stillwater Lake Carl Blackwell Pawnee Red Rock Marshall Kingfisher Watonga Weatherford Bessie Jay Pryor Skiatook Wynona Burbank Miami Vinita Nowata Talala Copan Foraker Newkirk Blackwell Mangum Hollis Erick Putnam Butler Cheyenne Breckinridge Lahoma Fairview Seiling Camargo Medford Cherokee Alva May Ranch Freedom Woodward Arnett Buffalo Slapout Beaver Hooker Goodwell Boise City Kenton Elk City Valliant Eva
Relative Greenness (RG) ranges from 0-100% and indicates how green each 1-km square pixel of land is in relation to a 16-year historical (1989-2004) 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 from weekly composite satellite imagery (AVHRR) using NDVI (Normalized Difference Vegetation Index) and is updated on OK-FIRE every Tuesday. 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.