Trend Analysis of Meteorological Variables in the Lake Van Basin, Turkey

Abstract

Climate change is one of the most important issues of our century and its effects are manifested in different ways around the world. In this study, both the aligned and the intra-block methods were used to detect trends to see climate change's impact. 6 meteorological parameters were selected in the Lake Van basin, which contains Turkey's largest lake. The 47-year time series of mean monthly temperature (℃), total monthly rainfall (mm), mean monthly relative humidity (%), total monthly surface evaporation (mm), mean monthly snow depth (cm), and total monthly insolation intensity (cal/cm2) parameters of 15 stations in the basin were evaluated for each month using non-parametric tests. In the series in which a statistically significant trend was detected, the beginning year and slope of the change were also determined. For the temperature parameter, the increasing trends were detected at all seasons. In the total monthly rainfall series, the upward trends were determined in March and September in the northeastern part of the basin. Upward trends were detected in the average monthly relative humidity series in winter. From the total monthly insolation intensity time series, autumn and spring were determined to have increasing trends. The trend analysis of mean monthly snow depth showed that there were downward trends in November and February. For the evaporation parameter, a decreasing trend was detected only in October.