Elaboration of climatic maps using GIS. Case study: Olãnesti drainage basin, Romania.

Creating precise climatic maps (temperature and precipitation map especially) on small areas such as drainage basins or landform units is always very useful for ecology of plants, distribution of vegetation and also different types of agricultural land. The geographic information system (GIS) analysis of several key-factors (aspect and slope of terrain, insolation degree, thermal gradient, geology and structure of landforms) offers the necessary tools to operate with in order to create an accurate climatic map. This method was applied in order to create a map showing the distribution of temperatures in the Olanesti drainages basin, a 235 km2 area located at middle latitude, in Romania. After creating the DEM, aspect and slope of the terrain, reclassifying categories and calculating the thermal gradient, a map showing the distribution of the annual mean temperature is obtained. Other climatic parameters could be calculated for small areas too, with precise results. These demonstrate that not only elevation and mathematical location of an area are important factors in the distribution of temperature, but also the aspect, the gradient, the insolation, the type of rock and the structure.