Droughts in central Chile using different indices during the 1981-2010 period

Abstract

The different dimensions of meteorological drought in central Chile in order to characterize their occurrence at multiple time scales and find evidence of variability and change in frequency are analyzed. For that, there are 27 meteorological stations at daily resolution arranged, which allow the identification of dry periods under the threshold of 0.1 mm. Besides establishing dry spells and its persistence (using the Besson index), the standard precipitation index (SPI) was applied to determine the internanual varibilidad of drought, precisely in a region with semiarid and Mediterranean climate. The results show greater persistence of dry days in the region of Valparaíso, which is consistent with the length of dry spells in many cases exceeding 22 days a year. The event La Niña in the winter of 1998 caused the longest streak of dry days of the rainy trimester (67 days), totaling 86 days without rain. However, it has not been able to prove their variability and changes in frequency.