92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Tuesday, 24 January 2012
Prediction of New Drought Class Transitions Using Markov Chains
Hall E (New Orleans Convention Center )
Chi-Han Cheng, University of Central Florida, Orlando, FL

Drought is a natural phenomenon that occurs when a significant decrease of water availability is observed 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 limitations in data sources. ENSO influences the climate of Florida; where El Niņo years tend to be cooler and wetter, and La Niņa 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 presented a 32 km high resolution land use adapted drought index on five different land uses (lake, urban, forest, wetland, and agriculture) in Florida was developed based on the NARR 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 Niņa driven drought impacts. Finally, a Markov chain model has applied for drought prediction based on the new drought classification.

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