Hydrological and agricultural droughts assessment in a semi-arid basin: Inspecting the teleconnections of climate indices on a catchment scale

Abstract

The hydrological and agricultural droughts and their characteristics were evaluated using the Standardized Streamflow Index (SSFI) and Standardized Soil Moisture Index (SSI) across the Konya Closed Basin (KCB) in Turkey, respectively. The Modified Mann-Kendall (MMK) trend method was applied to detect trends over the KCB. Furthermore, the teleconnections of various large-scale climate indices (LSCI: NAO, AO, PDO, SCAND, POLEUR and EA/WR) over 3-month SSFI and SSI series were considered through cross wavelet transform (XWT) technique. The analysis indicated an increase in drought duration and severity since 1999. The MMK test revealed significant negative trends for SSFI series at different time scales. A series of MMK test on different SSI series exhibited trendless behavior over the northern parts of the KCB; however, significant negative (positive) trend on southeastern (southwestern) area appeared to be prevailing. Moreover, the results of XWT analysis in association with different LSCI and SSFI/SSI series demonstrated multiple considerable common powers on lower periods (i.e., less than 8 month). The XWT analysis showed significant relationship between the LSCI with drought indices in some periods and the absence of such associations in the remaining period.