EVALUATION OF METEOROLOGICAL AND HYDROLOGICAL DATA OF SAPANCA BASIN BY TREND ANALYSIS METHOD

Abstract

In this study, according to the data obtained from the monitoring stations in the Sapanca basin, trend analysis is applied to the meteorological and hydrological data of the lake Sapanca such as temperature, surface evaporation, moisture, rainfall and the water level of the lake Sapanca basin in order to examine the relation between them. Among the applied tests, the Mann-Kendall and Spearman rho tests were used. In order to determine the trend starting year, the Mann-Kendall degree correlation test was used. When the test results were examined, the Spearman rho and Mann -Kendall tests showed increasing trend in temperature and surface evaporation while they showed decreasing trend in moisture, rainfall and lake water level data. It was also determined with the Mann -Kendall degree correlation test (applied to determine the trend starting year) that there is a positive relation among trend starting year of every parameter. The increasing trends in temperature and surface evaporation show that temperatures will raise in following years and accordingly surface evaporation will rise, too. On the other hand, rainfall, relative moisture and the lake water level show decreasing trends. Lake water will decrease due to the reduced rainfall and water availability with the effect of the rising trends.