A Study of Mean Winter Circulation Characteristics and Energetics over Southeastern Asia |
| |
| Authors: | A P?Dimriapdimri@yahoocom" title="apdimri@hotmailcom Email author" target="_blank">apdimri@yahoocom" itemprop="email" class="gtm-email-author">Email author |
| |
| Institution: | (1) Research and Development Centre, Snow and Avalanche Study Establishment, Him Parisar, Sector 37A, Chandigarh, 160036, India |
| |
| Abstract: | A mean climatology is studied to examine atmospheric circulation characteristics to assess the wintertime (December, January,
February and March - DJFM) synoptic weather system affecting northern India. The main objective is to study the mean circulation
and mean energetics distribution pertaining to the winter season, which are embedded with an eastward moving synoptic weather
system in westerlies, called Western Disturbances (WDs). Forty years (1958–1997) of uninitialized daily re-analysis data of
the National Center for Environmental Prediction - National Center for Atmospheric Research (NCEP- NCAR, henceafter NCEP),
U.S. has been considered for this study. Winter circulations are considered over the domain 15°S–45°N and 30°E–120°E. This
domain is considered particularly to illustrate the impact of wintertime synoptic weather system Western Disturbances (WDs),
which travel towards the east over the western Himalayas during winter and yield an enormous amount of precipitation in the
form of snow. Large-scale balances of kinetic energy, vorticity, angular momentum, heat and moisture budget terms are analyzed.
The main findings of the study show that strong rising motion in the extratropical region brings a significant amount of precipitation
over the region of study. Also, horizontal flux of kinetic energy converges in the tropical region and diverges over the extratropical
region. It is seen that both the zonal and meridional component of kinetic energy contributes to the production of kinetic
energy in the upper troposphere. Vorticity budget shows that wintertime circulation over the western Himalayas is characterized
by a negative generation of vorticity. The relative and planetary vorticity advection contributes to the horizontal transport
of vorticity. The moisture flux transported into the region shows that in the middle tropospheric levels moisture undergoes
phase transformation due to turbulent exchange and hence releases latent heat. |
| |
| Keywords: | Circulation convergence/divergence vorticity diabatic heating |
| 本文献已被 SpringerLink 等数据库收录！ |
|
