Keetch Byram Drought Index (KBDI)
KBDI is a metrological drought index which was devised by John L. Keetch and George Bryam in 1968. KBDI measures soil moisture deficiency by accounting water gain or loss in the soil. (Evapotranspiration is minus and precipitation is plus). The index ranges from 0 to 800. Maximum temperature, daily rain fall and mean annual rainfall of particular location are used to calculate KBDI.
English unit equation
KBDI range displays the significance of drought
000 – 200: High soil moisture and no drought
200 – 400: Potential to drought
400 – 600: Drought
600 – 800: Sever drought
KBDI calculation from Remote Sensing Data
Dr. Wataru Takeuchi from Institute of Industrial Science, University of Tokyo formulates KBDI maps for Asia-Pacific region using satellite images since 2006 with collaboration of Geoinformatics Center, Asian Institute of Technology. Land Surface Temperature (LST) from MTSAT and daily precipitation from GSMAP data are used to calculate KBDI. KBDI product and KBDI anomaly with last five year average are 4km spatial resolution and they are daily published in Satellite-based drought monitoring and warning system (http://webgms.iis.u-tokyo.ac.jp/DMEWS/ or http://188.8.131.52/drought/) web sites.
The system gives drought warning if KBDI Anomaly exceeds 40%. The drought warning system is useful for agriculture in Asian region especially in rice cultivation. The system still in validation state and it is needed to validate with real ground truth data. Identifying actual relationship between satellites based KBDI and rice cultivation is very crucial for rice agriculture management and planning.
1. Keetch, J.J., & Byram, G.M., (1968), A drought index for forest fire control, USDA Forest Fire Research Paper SE -38.
2. Alexander, M.E., (1990), Computer calculation of KBDI-Programmers beware, Fire Management Notes, Vol 51, No 04.
3. Janis, J.M., Johnson, M.B., & Forhun, G., (2002), Near real time mapping of KBDI in the South Eastern United States, International Journal of Wildland Fire, Vol 11, PP 281-289.