Radiation, Advection and Mixed Freezing and Frost Risk Assessment and Zoning in Iran

Each year، frost causes extensive damage to all aspects of agricultural production. Therefore، quantification of frost risk occurrence is one of the most important factors in implementing agricultural insurance policies. In this study، a hierarchical algorithm for detecting advection and radiation frost has been presented using data of a network consisting of 51 meteorological stations of Iran during the period 1951-2009. Using 3-hours interval data، the percentage of the frost events occurrence were determined and categorized into three frost classes (i. e. advection، radiation and mixed frost). These occurrence percentages، known as frost risk، were further analyzed according to their geographical characteristics (latitude، longitude and altitude). Finally، frost risk map of Iran was generated. Analysis of frost risk maps showed that occurrence risk of radiation and mixed frost are more than advection frost across the country. Besides، it was found that the maximum values of risk for radiation frost with the threshold temperatures of 4 and 0 C are 10. 62% (Shahrekord station) and 7. 23% (Koohrang station). Corresponding values for advection frost are 7. 22% and 4. 07% respectively، both observed in Ardebil station.