Trend Analysis of Extreme Temperature Indices in the Beyşehir Sub-Basin

Abstract

Climate change manifests itself in many regions of the world in the form of significant increases and decreases in many hydrological and meteorological variables. For this reason, hydrologists and meteorologists have often tried to identify trends in many hydrometeorological time series such as precipitation, streamflow, temperature, evaporation, and wind speed. Temperature is one of the meteorological parameters most affected by climate change. Twenty-seven climate extreme indices (17 temperature indices and 10 precipitation indices) have been proposed by the Expert Team on Climate Change Detection and Indices (ETCCDI) in order to examine the effect of climate change on temperature and precipitation parameters. In this study, the daily minimum and maximum temperature data of the Seydişehir (No: 17898) and Beyşehir (No: 17242) meteorology stations located in the Beyşehir Sub-Basin of the Konya Closed Basin for the period 1964 - 2019 were used. 8 of 17 temperature indices were used to examine the effect of climate change on the temperature parameter in the Beyşehir Sub-Basin. The extreme temperature indices used were frost days (FD), tropical nights (TR), summer days (SU), icing days (ID), warmest days (TXx), warmest nights (TNx), coldest days (TXn), coldest nights (TNn). Mann-Kendall, Şen Innovative Trend and Linear Regression methods were used when trend analysis of temperature indices was carried out. The trend analysis results showed that there is generally an increasing trend in the extreme temperature indices examined for both Seydişehir and Beyşehir stations. The decreasing trend was obtained in FD and ID at Seydişehir station, and only in TNn indice at Beyşehir station. However, these decreasing trends are not statistically significant.