Developing A Regional Land Use Drought Index In Florida

Drought is a natural phenomenon that occurs when a significant decrease of water availability during a significant period of time and over a larger area. Drought indices can be a useful tool to assess and respond to drought. However, current drought indices could not fully show the land use effects and they have limitation in data sources. ENSO influence the climate of Florida; where El Niño years tend to be cooler and wetter, and La Niña years tend to be warmer and drier than normal in the fall through the spring, with the strongest effect in the winter. Both prolonged heavy rainfall and drought potentially have impacts on land uses and many aspects of Florida's economy and quality of life. Hence, understanding local ENSO patterns on regional scales and developing a new land use drought index in Florida are critical and necessary in agriculture and water resources planning and managements. This paper presents a 32 km high resolution land use adapted drought index on five different land uses (lake, urban, forest, wetland, and agriculture) in Florida based on the National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (RR) data from 1979 to 2002. The new regional land use drought indices were developed from normalized Bowen ratio and the results show that they could reflect not only the level of severity in drought events resulting from land use effects, but also La Niña driven drought impacts.