تحلیل همدیدی نقش جت جنب‌حاره‌ای در ترسالی‌های جنوب غرب ایران

هدف از انجام این پژوهش تعیین بهترین موقعیت استقرار و الگوی کشیدگی جت جنب ‌حاره‌ای برای ایجاد ترسالی در جنوب‌غرب ایران و همچنین انتخاب پرتکرارترین الگوی همدیدی در این منطقه است. بدین منظور داده‌های بارش روزانه‌ی ایستگاه‌های جنوب غرب ایران(خوزستان، چهارمحال و بختیاری و کهگیلویه و بویراحمد) طی دوره‌ی آماری در سه سیکل خورشیدی (1997 1986)، (2008 1997) و (2019 2008) از سازمان هواشناسی کشور دریافت شد. داده‌های مولفه‌ی مداری و نصف‌النهاری باد، ارتفاع ژئوپتانسیل در سطوح 250 و 300 هکتوپاسکال، slp، نم ویژه و امگا از از مرکز ملی اقیانوس‌شناسی و محیط‌شناسی ایالات متحده آمریکا (ncep/ncar) با قدرت تفکیک مکانی 2.5 × 2.5 درجه‌ی جغرافیایی دریافت شد. سپس با استفاده از تحلیل عاملی و بررسی‌های چشمی، پرتکرارترین الگوها برای هر سه سیکل خورشیدی مشخص شدند. بررسی نقشه‌های تراز زیرین، مرزی و میانی وردسپهر نشان داد که در ترسالی‌های شدید جنوب‌غرب ایران، استقرار پرفشار عربستان بر روی دریای عرب و عمان و فراررفت رطوبت این دریاها به دامنه‌ی شرقی کم‌فشار سودان و شکل‌گیری ناوه‌ی عمیق در غرب ایران از اروپا تا جنوب سودان و فرارفت سرد جنب قطبی بر دامنه‌ی غربی کم‌فشار سودان، مناسب‌ترین الگو برای بارش‌های سنگین و تداوم چند روزه‌ی آن در جنوب‌غرب ایران می‌باشد. همچنین نتایج نشان داد که بهترین موقعیت استقرار جت جنب‌حاره برای تقویت سامانه‌های بارشی، محدوده‌ای بین مصر تا سواحل غربی خلیج فارس در جنوب عراق است در صورتی که هسته‌ی جت در شمال‌غرب عربستان قرار بگیرد. و منبع اصلی رطوبت سامانه‌‌ها در تمام نمونه‌های بارشی دریاهای عرب، عمان و مدیترانه است.

synoptic analysis of the role of the subtropical jet stream in wet of south west of iran

abstract introductionthe purpose of this research is to determine the best deployment position and stretching pattern of the side to side jet to create tarsal in the southwest of iran, as well as to select the most frequent synoptic pattern in this region.materials and methodsthe daily rainfall data of stations in the southwest of iran (khuzestan, chaharmahal, bakhtiari, kohgiluyeh, and boyer ahmad) during the statistical period in three solar cycles (1986 1997), (1997 2008) and (2008 2019) were received from the national meteorological organization. orbital and meridional wind component data, geopotential height at 250 and 300 hpa levels, slp, specific humidity and omega from the us national center for oceanography and environment (ncep/ncar) with a spatial resolution of 2.5 × 2.5 degrees. received. then, using factor analysis and visual inspection, the most frequent patterns were determined for all three solar cycles.results and conclusionthe examination of the maps of the lower, border and middle level of the troposphere showed that in the severe droughts of southwest iran, the establishment of high pressure arabia over the arabian and oman seas and the movement of moisture from these seas to the low pressure eastern slope of sudan and the formation of a deep trough in the west of iran from europe to southern sudan and cold subpolar advection on the western low pressure slope of sudan is the most suitable pattern for heavy rains and its continuation for several days in the southwest of iran. the best location of the subtropical jet to strengthen the rain systems is the area between egypt and the western coast of the persian gulf in southern iraq, if the core of the jet is located in northwestern saudi arabia. and the main source of system moisture in all precipitation samples is the arabian, oman and mediterranean seas.abstract introductionthe purpose of this research is to determine the best deployment position and stretching pattern of the side to side jet to create tarsal in the southwest of iran, as well as to select the most frequent synoptic pattern in this region.materials and methodsthe daily rainfall data of stations in the southwest of iran (khuzestan, chaharmahal, bakhtiari, kohgiluyeh, and boyer ahmad) during the statistical period in three solar cycles (1986 1997), (1997 2008) and (2008 2019) were received from the national meteorological organization. orbital and meridional wind component data, geopotential height at 250 and 300 hpa levels, slp, specific humidity and omega from the us national center for oceanography and environment (ncep/ncar) with a spatial resolution of 2.5 × 2.5 degrees. received. then, using factor analysis and visual inspection, the most frequent patterns were determined for all three solar cycles.results and conclusionthe examination of the maps of the lower, border and middle level of the troposphere showed that in the severe droughts of southwest iran, the establishment of high pressure arabia over the arabian and oman seas and the movement of moisture from these seas to the low pressure eastern slope of sudan and the formation of a deep trough in the west of iran from europe to southern sudan and cold subpolar advection on the western low pressure slope of sudan is the most suitable pattern for heavy rains and its continuation for several days in the southwest of iran. the best location of the subtropical jet to strengthen the rain systems is the area between egypt and the western coast of the persian gulf in southern iraq, if the core of the jet is located in northwestern saudi arabia. and the main source of system moisture in all precipitation samples is the arabian, oman and mediterranean seas.abstract introductionthe purpose of this research is to determine the best deployment position and stretching pattern of the side to side jet to create tarsal in the southwest of iran, as well as to select the most frequent synoptic pattern in this region.materials and methodsthe daily rainfall data of stations in the southwest of iran (khuzestan, chaharmahal, bakhtiari, kohgiluyeh, and boyer ahmad) during the statistical period in three solar cycles (1986 1997), (1997 2008) and (2008 2019) were received from the national meteorological organization. orbital and meridional wind component data, geopotential height at 250 and 300 hpa levels, slp, specific humidity and omega from the us national center for oceanography and environment (ncep/ncar) with a spatial resolution of 2.5 × 2.5 degrees. received. then, using factor analysis and visual inspection, the most frequent patterns were determined for all three solar cycles.results and conclusionthe examination of the maps of the lower, border and middle level of the troposphere showed that in the severe droughts of southwest iran, the establishment of high pressure arabia over the arabian and oman seas and the movement of moisture from these seas to the low pressure eastern slope of sudan and the formation of a deep trough in the west of iran from europe to southern sudan and cold subpolar advection on the western low pressure slope of sudan is the most suitable pattern for heavy rains and its continuation for several days in the southwest of iran. the best location of the subtropical jet to strengthen the rain systems is the area between egypt and the western coast of the persian gulf in southern iraq, if the core of the jet is located in northwestern saudi arabia. and the main source of system moisture in all precipitation samples is the arabian, oman and mediterranean seas.