The agroclimatic classification of northern east of Iran based on thermal and humidity conditions

Climatic classification based on ecological capacity and weather conditions of different regions has great importance in agroclimatic studies. In this study an agroclimatic classification of north eastern of Iran using Papadakis and effective rainfall methods has been carried out. CROPWAT ver.8.0 software was used to calculate effective rainfall. To regionalize the point data, geostatisitc methods were used. The obtained values were elaborated using ARCGIS 10.2 to generate the spatial distribution maps. Cross-efficiency evaluation of geostatistical methods indicated that Empirical Bayesian Kriging (EBK) produces a higher efficiency. Based on the winter and summer temperature and plants temperature stability, ecological types of oats and cotton are dominant in the region, respectively. According to these ecological types, a warm continental regime is dominant the region. Considering humidity conditions of the region expressed in terms of potential evapotranspiration (PET) and monthly rainfall, the climate of northeastern Iran categorized as arid Mediterranean and arid climates. The highest amount of effective rainfall, as a major moisture index, is observed in month of March and April. Based on the ratio potential evapotranspiration to monthly precipitation ration from the north to the south, the number of humid months decreases southward. The spatial distribution of (PET) increases from the north to the southern parts.Similarly, effective rainfall and humidity index (HI) values were decreased. Taking into account the thermal and humidity conditions, the northeastern region of Iran’s climate is classified as continental arid/ semi-arid and desert classes. Humidity conditions play a major role in determining climate classes in the studied region. Further studies using other climatic indices are recommended for more scrutiny.