نوع مقاله : مقاله علمی - پژوهشی
نویسندگان
1 گروه جغرافیای طبیعی، دانشکده علوم جغرافیایی، دانشگاه خوارزمی تهران
2 دانشجوی دکترای آب و هواشناسی، گروه جغرافیای طبیعی، دانشکده جغرافیا و برنامه ریزی محیطی، دانشگاه سیستان و بلوچستان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Torrential rains because of the suddenness of damage in different parts of the infrastructure, construction and agricultural
areas of high rainfall regions of our country, especially in Regions with abundant rainfall. In the present
study, we have identified sea level pressure patterns and analyzed the synoptic and thermodynamic conditions of super
heavy rainfall days in Golestan province.For this purpose, first, using ground station data and taking into account two
threshold conditions above 98% percentile and over 50% incidence, 15 days of super heavy rainfall were extracted during
the spring of the 1970–2019 statistical period.Sea level pressure data are extracted on 0.25 /0 0.25 degree arc cells at 10 to
70 degrees north latitude and 10 to 90 degrees east longitude from the European Mid-Term Forecast Center (ECMWF)
Were. Cluster analysis by Ward integration method was performed on the sea level compressibility matrix data for
15 days of super heavy rainfall and 3 synoptic pressure patterns observed during spring super heavy rainfalls events
of Golestan province. The results of the synoptic analysis of the maps showed that during the heavy rainfall events,
tabs of cold pressures based on Europe, Russia and Siberia and multi-core warm pressures located in the Arctic, mideastern
regions of Iran, Pakistan and Aral and Balkhash Lake are spread northeast of Iran and Golestan province.These
conditions have created active frontal zones and consequently severe pressure gradient in northeast and atmosphere of
Golestan province and have led to super heavy rainfall days in the study area. The results of moisture flux convergence
function analysis also showed that the highest moisture flux convergence was at lower atmospheric levels (1000 and
850 hPa) and by Caspian, the Persian Gulf and Oman water resources, respectively. But in the middle levels of the
atmosphere (700 and 500 hPa) with the zonal atmospheric currents, In addition to the Caspian Sea, Mediterranean and
Black seas sources have also been responsible for the moisture supply of these rainfalls.
کلیدواژهها [English]
به هنگام بارشهای بهاری فراگیر ایران،. پژوهشهای جغرافیای طبیعی، دوره 49 (3)، صص 523-539.