Simulation of Airflow in Kashmir Valley for a Summer Day

N. Ramanathan Center for Atmospheric Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India

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K. Srinivasan Center for Atmospheric Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India

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Abstract

The airflow over the Kashmir Valley for a summer day was studied using a numerical mesoscale model. Srinagar observations were used as initial data. The surface orography, soil moisture variations, cloud cover, and vegetation effects were included in the computations. The combined effect of these factors on the development of atmospheric circulations in the valley was obtained quantitatively, and the three-dimensional model simulated results are compared with available observations. The following principal results were obtained. (a) The simulated surface temperature pattern shows a close correlation with the terrain elevations and prevailing atmospheric stabilities, (b) the intensities of katabatic and anabatic winds developed at the slopes are governed by terrain asymmetries and aspect ratio of the slopes, (c) the boundary layer depths developed at different locations in the valley are found to be nonuniform, and (d) the convergence zone formed during nighttime shows an irregular distribution.

Corresponding author address: Dr. N. Ramanathan, Centre for Atmospheric Sciences, Indian Institute of Technology, Hauz Khas, New Delhi - 110 016, India.

nrnathan@cas.iitd.ernet.in

Abstract

The airflow over the Kashmir Valley for a summer day was studied using a numerical mesoscale model. Srinagar observations were used as initial data. The surface orography, soil moisture variations, cloud cover, and vegetation effects were included in the computations. The combined effect of these factors on the development of atmospheric circulations in the valley was obtained quantitatively, and the three-dimensional model simulated results are compared with available observations. The following principal results were obtained. (a) The simulated surface temperature pattern shows a close correlation with the terrain elevations and prevailing atmospheric stabilities, (b) the intensities of katabatic and anabatic winds developed at the slopes are governed by terrain asymmetries and aspect ratio of the slopes, (c) the boundary layer depths developed at different locations in the valley are found to be nonuniform, and (d) the convergence zone formed during nighttime shows an irregular distribution.

Corresponding author address: Dr. N. Ramanathan, Centre for Atmospheric Sciences, Indian Institute of Technology, Hauz Khas, New Delhi - 110 016, India.

nrnathan@cas.iitd.ernet.in

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