Frequency Analysis of Cold Waves Occurrence in Semnan Province

Cold waves are natural phenomena normally occurring in winter and autumn seasons. They likely cause significant damage to agricultural crops and garden yields. Accordingly, both monitoring and prediction of cold waves occurrence are essential for planning and managing the associated risks beneficially.

This study aims at analyzing cold waves data in Semnan province, enhancing a better understanding of this phenomenon, and suggesting practical solutions for effective management. To meet this target, the minimum daily temperature data were analyzed from 1980 to 2020. To identify the cold waves, the standardized minimum temperature (Z-index) was calculated during the same period in Semnan province.

Our findings revealed that the highest occurrences of cold waves occurred in Semnan city with a fairly long-term duration (In 2007, there were two cold waves lasting 3 and 7 days, and in 2016 there was a cold wave lasting 6 days). Moreover, Shahmirzad, Shahrood and Miamey stations recorded the lowest minimum temperature (-16.4 ◦C, -14.2 ◦C, -14.2 ◦C) in November 2016, respectively.

Results demonstrate that the cold waves occur with 10-year return period. Subsequently, developing applicable management plans are essential to reduce cold waves exposures and damages.