Investigation and analysis of climate change and siberian high-pressure system during drought and wet periods in the Iranian plateau

Abstract

In this research, daily rainfall data from a 29-year statistical period (1990–2018) for 30 synoptic stations of north–eastern Iran were obtained by statistical methodology from the Iranian Meteorological Organization (Tehran). From these maps, the clustering system (blocking) and the study of various atmospheric blocking systems were used to study and investigate the climate (dry and humid phenomenon) of north–eastern Iran. Drought and mildew is an important environmental issue, so recognizing its characteristics is very important. The most common monitoring of drought conditions is the drought index. The SPI is applicable because of its simplicity, versatility and applicability in any type of climate. Therefore, it is a well-known index for dry drought monitoring. Therefore, it is used for drought monitoring and estimation of its occurrence in the north–eastern region of Iran, in the dry area and mountainous regions of Iran. The SPI was used in combination with the Markov chain, and the continuity, intensity and abundance of drought and mildew for the 12 months of the year were studied and examined. The results of this study showed the effect of the tongue of the Siberian high pressure and the tropical highlands of Azure and the Tibetan plateau (Himalayan mountain range) and the Mongolian plateau and Siberian plateau The Arabian Peninsula has been involved in the creation of a block diagram (blocking of atmospheric conditions) whose intrusion and divergence have prevented the low pressure of the Mediterranean to the north–east of Iran and play an effective role in creating the block in the dry periods, and the continuation dry and wet periods are visible on the Iranian plateau.