شناسايي الگوهاي گردشي پديده يخبندان با كاربرد تحليل مولفه هاي مبنا و تحليل خوشه اي (مطالعه موردي: استان فارس)

The knowledge of circulating patterns of frost phenomenon with application principle components analysis and clustering analysis "Case study: Fars province"

Frost is one of climatic phenomenon by damaging in economic difference sections specially: agricultural. So, itʹs important to identify this phenomenon in Fars province, because of agricultural activities. The aim of this research to recognize circulating patterns in atmosphere levels for frost occurrences. It can forecast from mapping of air different levels. So, with application principle component analysis up to correlation matrix on geopotential height in 500HP level and see level pressure data in geographical limits 0-70° eastern longitude and 20-600 northern latitude to identify essential elements of atmosphere formation circumstance. Afterwards, the usage of clustering analysis with ward method on components scores, identified circulating patterns. As a result, Siberian high pressure and high pressures of European north and northeast extend toward Iran to reduce degree of temperature in Fars different regions. In addition to The core of high pressure more than 1025HP is formed in Zagros heights that to play basic role in the intensification and durability of province frosts. In 500HP level with settlement ridge eastern section of Fars province it is caused to move very frigid air from up latitude toward low. In this situation the degree of air petered in different regions of Fars. Particular, in the northern, central and northwestern parts.