Extraction and determination of airstream patterns over the North west of iran on the basis of calculating vorticity

Irani, Naser and Salahi, Bromand and Zeinali, Batool and Aalijahan, Mehdi (2016) Extraction and determination of airstream patterns over the North west of iran on the basis of calculating vorticity. Masters thesis, University of Mohaghegh Ardabili.

Text (استخراج و تعیین الگوهای جریان هوای حاکم بر شمال‌غرب ایران با محاسبه‌ی چرخندگی) Naser Irani.pdf Download (2MB)

Abstract

In order to detect patterns of air flow in northwest of Iran, was produced sea level air pressure data of the NCEP reanalysis data for 12z of 3652 days during the period from 2005 to 2014 at 9 points from ground level in the range 32.5 to 42.5 north latitude and 40 to 55 east longitude and were extracted 25 models based on calculations of vorticity, wind speed and direction per day. was analyzed the slp, hgt and vorticity wind maps of each representative days. were identified and classified the extraction patterns in nine main patterns. The most frequent pattern is E (eastern) and is dominant in summer with a frequency of 30.84%. It is followed by pattern SE (Southeast), is dominant in autumn with 25.19%. the third pattern is M (undetermined), is dominant in early spring with 21.03%. pattern NE (Northeast) is more frequency in late spring whit 9.66%. the patterns: W (western), S (southern), N (north) and A (Anti-cyclone) are less than 3.53 frequencies and not see at least 4 warmer months of year and are frequent in early winter. Pattern C (Cyclonic) is lowest frequency with 1.01% and More can be seen in winter. The results show that, There is 4 main path of air flow to the study area, That specified with a hod in 500mb Geopotential Heights map. The first path is the Caspian Sea that the main route of pattern E, with Atlantic air masses. The second route is the Lake Balkhash that the main route of pattern SE and Siberian air masse. The Third route is the Black Sea that the main route of pattern NE From the European. The fourth route is the Mediterranean that the N and Cyclonic patterns Airflow come fram here. During the study period, increasing trend the frequency of patterns such as SE and S that are the entry main route of them from Lake Balkhash.

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