Bridging drought and climate aridity

摘要

Drought is a complex phenomenon, and tracing its periodicity is often a puzzle. In time and space, the frequency of drought events inspires suspicion of connections with local climate features including aridity gradients. The present study analyzes the connection between drought patterns and regional aridity gradients. Specially, the study addresses environmental water stresses in the Great Plains of the United States over the two time periods: 1951 to 1982 and 1983 to 2014. The regional aridity gradients were estimated then analyzed along with the time series of the standardized precipitation index. Employing a multivariate regression on principal components model, the study evaluates the connection between drought patterns and regional aridity gradients. The results indicate significant relationships between drought patterns and climate aridity over the time. The comparison of the aridity gradients of the Great Plains region over the two time periods indicates a wetter period from 1983 to 2014. Meanwhile, there is a shift of drought intensity, as the tendency for exceptional drought events increased significantly across the Great Plains during the period 1983 to 2014. The contrast observed with the wetting trend and the increased drought severity implies that exceptional droughts are not necessarily the cause of a drying climate. A consideration of this paradigm may help to better implement drought monitoring strategies at regional levels. (C) 2017 Elsevier Ltd. All rights reserved.