Interaction of Zagros heights effects on precipitation and wind vertical velocity of convective systems in the west of Iran

Basati, Saeed; Yarahmadi, Dariuosh; Nasiri, Behrouz; Rafati, Somayeh

doi:10.22111/jneh.2018.19970.1241

Interaction of Zagros heights effects on precipitation and wind vertical velocity of convective systems in the west of Iran

Document Type : Research Article

Authors

¹ Ph.D Graduated of Climatology, Lorestan University, Iran.

² Associate Professor of Climatology, Lorestan University, Department of Geographical Science, Iran.

³ Assistant Professor of Climatology, Lorestan University, Department of Geographical Science, Iran.

⁴ Assistant Professor of Climatology, Seyed Jamaleddin University, Asadabad, Hamedan, Iran.

10.22111/jneh.2018.19970.1241

Abstract

Considering the significance of Zagros heights in precipitation distribution, the present study using the RegCM4 model and its simulations, the effect of Zagros heights on convective Cumulative precipitation and vertical velocity of different levels of the atmosphere was investigated. The required data was obtained from NCEP/NCAR with a 2.5 resolution from 22 to 38 latitude and from 38 to 58 longitudes on a grille with a horizontal resolution of 10 KMs and 30 SEC time steps for 2000 to 2005.Comprehensive cumulative convective systems were evaluated in two control run an experimental run and, effects of the Zagros heights in warm and cold seasons of the year was examined on these parameters. Results indicated that cores of rainfall during December-January after crossing system have been weakened, while April systems in East Zagros have continued to operate with the same power. Zagros heights in the months of December-January increased rainfall in West Iran and reduced in the Zagros East. In contrast, in April, there is no significant difference between the two runs in the Zagros East between convective precipitations. And maximum precipitation in both runs, is focused in West Iran and Zagros region and its minimum is focused Zagros East and Iran's central plains; But by eliminating the Zagros heights, the convective rainfall this month has increased on the shores of the Caspian Sea. The Zagros heights has to effect on vertical wind velocity profiles of Low levels and the speed and extent of the jet stream cores of high levels of the atmosphere; So that in April resulted movement atmospheric jet stream from level 200 to 400 hp and increases their speed and extent; So, the flows pattern of the mesoscale convective systems and the convective precipitation resulting from them were influenced by the elevation pattern; and kind and how the Zagros heights effects on convective precipitation and vertical profiles of wind speed in the warm and cold months of year is different; in a way that, the wind slowed down at low levels of the atmosphere in December and increased in January and April.

Keywords

References

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