به منظور بررسی شرایط سینوپتیکی مربوط به بارش 31 دسامبر1984 تا 4 ژانویه 1985 رود خانه دالکی،الگوی گردش فوقانی وتحتانی ونحوه فرارفت آن در زمان بارش بررود خانه دالکی مورد بررسی قرار گرفت. جهت بررسی این بارش ابتدا نقشههای روزانه سطح زمین و ترازهای 700 و 500 هکتوپاسکال از 48 ساعت قبل از وقوع بارش استخراج ومورد بررسی وتحلیل قرار گرفت ونتایج زیر حاصل گردید:بر روی نقشه سطح زمین، نقش اصلی و کنترل کننده باپر فشار سیبری،پر فشار دینامیکی آزور و حالت ادغام شده دو سیستم کم فشار سودان و مدیترانه میباشد. در ترازهای بالاتر نیز سیستمهای اصلی کنترل کننده، مرکز ارتفاع زیاد آزور در پشت سیستم و مرکز ارتفاع زیاد عربستان در جلو سیستم و تراف عمیق شمال آفریقا میباشد.نتایج این مطالعه میتواند درپیش بینی بارشهای سنگین و سیل زا وهمچنین پیش آگاهی برای برنامه ریزی و مدیریت بهترمنابع آب منطقه به کار برده شود.
عنوان مقاله [English]
Synoptic analysis of heavy rain in South of Iran (case study: Heavy rain in the Dalaki river basin in period of 31 December 1984 - 4 January 1985)
Â Synoptic analysis of heavy rain in South of Iran (case study : Heavy rain in the Dalaki river basin in period of 31 December 1984 - 4 January 1985) Â Â A. Parandeh Khozani. ( * ),Â Senior Expert of Climatology in Esfahan Meteorology Bureau Â email: firstname.lastname@example.org Â Â Â H. Lashkari.Â Â Associate professor of climatology, Sahid Beheshti University, Tehran, Iran. Â Received: 18 May 2009 / Accepted: 10 March 2009, 35-37 P Â Â Â Extended Abstract Â 1- Introduction Â Heavy rain is the most common and widespread of all weather-related natural disasters that have caused considerable losses to the human throughout history. Â In south of Iran and Dalaki river basin this damages are significant. Â Thus, Diagnosis and Prediction of distractive heavy rains and its intensity in region is very important (essential). Â The aim of this study is to recognize the synoptic pattern leading to distractive rain in Dalaki river basin located in south of Iran. Â Â Â In order to prevent damages of these phenomena and water resource management, it is better to study heavy rain in different regions with synoptical method. Â Â 2- Metodology Â In order to obtain this, Circulation pattern of the upper and lower and its advection during precipitation was investigated. At First, Daily synoptic maps from surface to 500 hpa levels of 48 hours before the occurrence of precipitation were investigated and finally considering their arrange, extension, direction of movement, the position of cyclones and anti-cyclones were analyzed. Furthermore, in upper levels trough lines were carefully traced and analyzed. Â Â Â Â 3- Discussion Â Strengthing activity mentioned system has been influenced by following factors: Â -The existence of an anticyclone on Oman Sea and the East of Arabestan provides enough moisture for feeding this system in the highest precipitation day. Â -The Spread of Siberian anticyclone tongue over Iran and South of Iran, before the start of precipitation, causes the falling of cold weather from high latitude and increase the thermal gradian over the region. Â -The existence of high Azores center at the levels of 500 and 700 Hectopascal that causes strengthening thermal gradian over the region by falling of cold weather from its East over the North of Africa and Meditranian Sea and also made Sudan heat low centers and Red Sea convergence zone to be active and become dinamic and termodinamic Â -The existence of high Arabestan at the levels of 700 and 500 Hectopascal is need for transition of hot and humid weather into the system. Â Â 4- Conclusion Â Synoptic analysis of heavy rain in Dalaki river basin Located in south of Iran , showed that in surface level ,heavy rain mainly is caused by Siberian anticyclone and high Azores and simultaneous merging of the Sudan heat low (SHL) system and Mediterranean frontal system (MFS). 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