Thornthwaite method based climate classifying and generation of GIS based climate boundary maps: a case of Kozlu District on the Western Black Sea coast of Turkey

Abstract It is necessary to know the climatic conditions and classes in order to address a region’s climate-related problems and ensure its sustainability. Kozlu, located on the Black Sea coast in the Black Sea region of Turkey, is a district where underground mining, fishing, sea tourism and agricultural activities are conducted. The district faces challenges due to geo-environmental factors, including landslides, subsidence, and floods, necessitating the identification of climate classes and characteristics to support sustainable development. For this reason, data for the last thirty years from four meteorological stations representing the Kozlu district were obtained. It was associated with the location, and then the Kriging interpolation method was applied. After this, water balances were calculated by applying the Thornthwaite climate classification method, and GIS-based climate boundary maps were generated using the same method. In the climate classification made by the Thornthwaite method, it was observed that the humid climate characteristic was dominant throughout the district. The drought index indicates moderate summer water deficiency in the north and the south of the district. In the south of the district, it is characterized by little or no water deficiency. Considering that the annual precipitation amounts at the stations located in the south of the district are higher than in the other areas, and the time interval in which water deficiency occurs is shorter, the fact that the climate feature of little or no water deficiency is seen moving south in the study area shows that the results are quite compatible with each other. In addition, according to the results of the summer concentration index, the entire study area was observed to be dominated by a marine climate. Climate boundary maps consisting of precipitation efficiency, temperature efficiency, drought and summer concentration index maps will contribute to monitoring climate change in the district.