Synoptic analysis of extreme and exteremly Wet Period in southern Iran

Aridity and drought are inseparable features of every climate. But in arid and semi-arid climates, tarsal is an ideal opportunity to restore or compensate for the lack of water in the region. The southern part of Iran has a dry climate despite access to the huge moisture resources of the warm southern seas. To conduct the research, first, the daily rainfall data of all the synoptic stations of the southern provinces of the country, which had complete statistics in the 33-year statistical period (1986-2019), were extracted. Then, using ZCI, ZSI, and SPI indicators, droughts and droughts were identified. Finally, the years that were in extreme poverty in all three above indicators were selected as samples. In the next step, the data of specific humidity, orbital and meridional wind, geopotential height and omega for all atmospheric levels in the lower and middle layers of the Verdosphere were received from the NCEP/NCAR site for all rainy days. Examining the maps of subsurface levels of the Verdspehr (sea, 1000 and 925 hectopascals) showed that three main systems control the pattern of the subsurface layer of the Verdspehr. The Siberian, Tibetan and Mohajer high-pressure fronts spread over the warm waters of the Oman and Arabian seas from 3 to 7 days before the start of the system's rainfall and spread the necessary moisture into the Sudanese system. It plays a very important role in determining the entry path of the system, the expansion pattern of the Mediterranean trough and the duration of the activity of the precipitation system in the middle layer of the Arabian Wardspehr