كليدواژه :
ديناميك جو , تاوايي پتانسيل , تروپوپاز , بارش سنگين , غرب ايران
چكيده فارسي :
به منظوردرك ساختار ديناميك جو در زمان رخداد بارش هاي سنگين غرب ايران از دو پايگاه داده استفاده شد. ابتدا با بررسي 14 ايستگاه همديدي سازمان هواشناسي كشور واقع در منطقه طي سال هاي 1990 تا 2012 بارش هاي فراگير با بيش از 20 ميلي متر در منطقه استخراج شد. در گام بعدي با مراجعه به تارنماي مركز اروپايي پيش بيني ميان مدت جوي(ECMWF) با تفكيك افقي 0.125×0.125 درجه جغرافيايي اخذ گرديد. براي تحليل ها از معادلات ديناميكي هم چون تاوايي پتانسيل بر روي سطوح فشاري ، جبهه‌زايي، فرارفت تاوايي نسبي و همگرايي شار رطوبتي استفاده شد. نتايج نشان داد كه در زمان رخداد بارش هاي سنگين و فراگير ناوه هايي بسيار عميق با عمق بيش از 20 درجه جغرافيايي تشكيل شده و سامانه هايي هم چون كم فشار قطبي در تراز مياني گسترش مي يابد. در اين زمان ضمن تشكيل كم فشار هاي بريده بر روي منطقه مقادير تاوايي پتانسيل بر روي سطوح همدرگاشت 330 درجه كلوين، در مناطقي هم چون درياي مديترانه، سياه و سرخ به بيش از PVU 6 و بر روي منطقه مورد مطالعه به بيش از PVU 3 مي رسد.
چكيده لاتين :
To understand the dynamic structure of the atmosphere at the time of heavy rainfall in western Iran,
two databases were used. First, by examining 14 synoptic meteorological stations of the Meteorological
Organization located in the study area during the years 1990 to 2012, inclusive rainfall with more than
20 mm was extracted. In the next step, by referring to the website of the European Center, the weather
forecast (ECMWF) with a horizontal resolution of 0.125 × 0.125 degrees was obtained. Dynamic equations
such as potential equilibrium on compression surfaces, fronting, partial equilibrium advection, and
moisture flux convergence were used for the analyzes. The results showed that during the occurrence
of heavy and pervasive rains, very deep boats with a depth of more than 20 degrees are formed and
systems such as low polar pressure spread in the middle level. At this time, while forming low shear
pressures on the region, the potential value values on the 330 ° K conjugate surfaces, in areas such as the
Mediterranean, Black, and Red, to more than PVU 6 and on the study area to more than PVU 3 Arrives. This
situation on the ground also contributes to the expansion of low pressures and strengthens instabilities,
so that by examining the relative fineness of the maximum positive values of this index correspond to
the western regions of Iran and eastern Iraq, which play a significant role in the development of systems.
It is important. In the upper layers and at the level of 250 hPa, due to the anomalies in the compression
veranda, the flow of the polar jet is extended to the lower latitudes and merges with the polar jet in the
Middle East and Iran. These conditions have played a significant role in intensifying instability in the region.
In the study of moisture sources, two sources were identified as main sources and two sources as sources
of heavy rainfall, respectively, the Red Sea and the Mediterranean Sea (as the main source) and the Persian
Gulf and the Black Sea (as moisture booster). Are considered.
