Local Hadley circulation over the Asian monsoon region associated with the Tropospheric Biennial Oscillation |
| |
| Authors: | P A Pillai K Mohankumar |
| |
| Institution: | (1) Department of Atmospheric Sciences, Cochin University of Science and Technology, Cochin, India |
| |
| Abstract: | Summary The Tropospheric Biennial Oscillation (TBO), a major interannual variation phenomenon in the Indo-Pacific region, is the result
of strong ocean-atmosphere coupling over the Asian-Australian monsoon area. Along with other meteorological and oceanographic
parameters, the tropical circulation also exhibits interannual oscillations. Even though the TBO is the result of strong air–sea
interaction, the circulation cells during TBO years are, as yet, not well understood. In the present study, an attempt has
been made to understand the interannual variability of the mean meridional circulation and local monsoon circulation over
south Asia in connection with the TBO. The stream function computed from the zonal mean meridional wind component of NCEP/NCAR
reanalysis data for the years 1950–2003 is used to represent the mean meridional circulation. Mean meridional mass transport
in the topics reverses from a weak monsoon to a strong monsoon in the presence of ENSO, but in normal TBO years mean transport
remains weak across the Northern Hemisphere. The meridional temperature gradient, which drives the mean meridional circulation,
also shows no reversal during the normal TBO cycle. The local Hadley circulation over the monsoon area follows the TBO cycle
with anomalous ascent (descent) in strong (weak) monsoon years. During normal TBO years, the Equatorial region and Indian
monsoon areas exhibit opposite local Hadley circulation anomalies.
Authors’ addresses: Prasanth A. Pillai, Research Scholar, Department of Atmospheric Sciences, Cochin University of Science
and Technology, Lakeside Campus, Cochin 682016, India; K. Mohan Kumar, Professor & Dean, Department of Atmospheric Sciences,
Faculty of Marine Sciences, Cochin University of Science and Technology, Lakeside Campus, Cochin 682016, India. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
