Piecewise wet and dry spell duration-number relationship and possible climate change impact identification in Turkey

Abstract

Wet (dry) spells correspond to successive surplus (deficit) in hydro-meteorology daily, weekly, monthly, or annual records according to above (below) of a given any threshold parameter value such as arithmetic average, median, mod, or quantile precipitation. Researchers generally consider wet (dry) spell durations and their numbers, but this paper also focuses on the climate change impacts. For this purpose, available hydro-meteorological records, obtained from different climatic and geographic regions of Turkey, are divided into two half parts, and the wet and dry spell (month) durations are plotted versus their numbers, where the scatter points appear as decreasing straight lines on semi-logarithmic paper, and their mathematical expressions are in the form of exponential functions. The slopes of these straight lines provide useful information about the climate change impacts on each meteorology station. The physical interpretations and explanations are provided through relevant tables and figures. The application of this procedure is presented for a set of meteorology station monthly rainfall records from different climate regions of Turkey.