TY - JOUR ID - 53120 TI - Synoptic Analysis of Hazardous T hunderstorms in Isfahan JO - Environmental Management Hazards JA - JHSCI LA - en SN - 2423-415X AU - Khazaei, Mahdi AU - Modiri, Ehsan AU - Modiri, Mahdi AD - PhD. Student of Climatology, University of Tehran, Iran AD - MS. in Agrometeorology, Azad Islamic University, Science and Research Branch, Tehran, Iran AD - Associate Professor, Malek-Ashtar University of Technology, Iran Y1 - 2014 PY - 2014 VL - 1 IS - 2 SP - 203 EP - 215 KW - geopotential height KW - Isfahan KW - synoptic systems KW - Thunderstorm KW - weather hazards DO - 10.22059/jhsci.2014.53120 N2 - Thunderstorms are sever weather phenomena which occur repeatedly in transitional seasons - fall and spring - in middle latitudes. These storms are among sever weather hazards which cause a lot of damage to agricultural fields, gardens, etc. Understanding the mechanism, genesis and development of these storms helps us in combatting or controlling them. This study looks at severe thunderstorms in Isfahan over a 19-years period (1990 -2008). At first the codes of thunderstorms which caused over 10 mm rains were extracted and then based on the data collected from NOAA NCEP-NCAR dataset - sea level pressure and 850 hPa and 500 mb geopotential height on days of rain - the required maps were drawn using Grads software and the precipitation patterns were identified. In this study, two general patterns were identified for thundershower in Isfahan. The first pattern (12 November 1993) at sea level pressure, anticyclone tongue that extends from the East through the Northern Sea of Oman and the Persian Gulf, caused moisture Advection in the study area and at pressure of 850 hPa level, cyclone with the contour 1500 geopotential meters Located on the region. At 500 hPa level, the study area is located completely in the deep trough western that in addition of providing moisture, has intensified instability to higher levels. In the second pattern (26 April 2006) a large low pressure center with 1008 hpa is located on the country. The flows direction in the system is such that flow moist air into the country and at the 850 hpa level, the study area is located fully in front of the cyclone whit contour curve 1470 geopotential meters that in addition to moisture advection of Persian Gulf into the country, has intensified instability in this level and the 500 hpa level, so the deep troughs western, passing through the country and the study area, has provided instability to the upper levels. UR - https://jhsci.ut.ac.ir/article_53120.html L1 - https://jhsci.ut.ac.ir/article_53120_b0fec3e2ec5b588de4d24344a3a815de.pdf ER -