introduction frost as a harmful climatologic phenomenon affects various human activities and biological processes. due to mountainous nature of kurdistan province as the study area of this research in one hand and type and diversity of effective air masses on the other, the frequency, severity and duration of this phenomenon in the province are outstanding. confronting frost could be one of the...

1. introduction droughts are long-term phenomena that can affect large areas and cause severe downturn in economic and social activities. recognizing this phenomenon, its features and properties, knowledge of facilities, capabilities and talents of areas and providing short and long term solutions leads to the effort of the surface water resource managers to prepare for drought mitigation. the ...