Vk. Lohani et Gv. Loganathan, AN EARLY WARNING SYSTEM FOR DROUGHT MANAGEMENT USING THE PALMER DROUGHT INDEX, Journal of the american water resources association, 33(6), 1997, pp. 1375-1386
The Palmer Drought Severity Index (PDSI) is used in a non-homogeneous
Markov chain model to characterize the stochastic behavior of drought.
Based on this characterization an early warning system in the form of
a decision tree enumerating all possible sequences of drought progres
sion is proposed for drought management. Besides yielding probabilitie
s of occurrence of different drought severity classes, the method asso
ciates a secondary measure in terms of likely cumulative precipitation
deficit to provide timely guidance in deciding drought mitigation act
ions. The proposed method is particularly useful for water availabilit
y task forces in various states for issuing drought warnings in advanc
e. The applicability of the technique is illustrated for the Tidewater
climatic division of Virginia.