Assessing spatiotemporal variability of drought in the US central plains

This paper examines the change in precipitation from 1900 to 2006 on a regional scale over a portion of the Central United States. Monthly precipitation data is kriged over the Kansas River Basin region. The Standardized Precipitation Index (SPI) is calculated at several time scales ranging from I to 12 months. The linear trend of SPI values over the time period is calculated and analyzed, showing many areas of increasing wetness throughout the area, with drying in isolated regions of the West and North. These isolated regions of drying overlap regions of heavy water use and irrigation, suggesting possible detrimental effects on agricultural production and aquifer levels if the trend continues. With the areas of increasing trend, however, it is unclear whether increased precipitation actually signifies any increase in water availability. Fourier analysis is also used to detect characteristic frequencies of SPI values. No difference in drought frequency patterns across the region was observed. (C) 2009 Elsevier Ltd. All rights reserved.