On the role of the cross equatorial flow on summer monsoon rainfall over India using NCEP/NCAR reanalysis data

Citation
Mrr. Kumar et al., On the role of the cross equatorial flow on summer monsoon rainfall over India using NCEP/NCAR reanalysis data, METEOR ATM, 70(3-4), 1999, pp. 201-213
Citations number
32
Categorie Soggetti
Earth Sciences
Journal title
METEOROLOGY AND ATMOSPHERIC PHYSICS
ISSN journal
01777971 → ACNP
Volume
70
Issue
3-4
Year of publication
1999
Pages
201 - 213
Database
ISI
SICI code
0177-7971(1999)70:3-4<201:OTROTC>2.0.ZU;2-M
Abstract
The role of the cross equatorial flow from the southern Indian Ocean on the Indian Summer monsoon is examined using the National Centre for Environmen tal Prediction (NCEP)/National Centre for Atmospheric Research (NCAR) data for the period January 1982 to December 1994. A comparison of NCEP/NCAR dat a with the satellite data retrieved from the Special Sensor Microwave Image r (SSM/I) sensor onboard the Defense Meteorological Satellite Program (DMSP ) exhibited a negative bias for the wind speeds greater than 4 m/s, whereas in the case of specific humidity, SSMI values exhibited a positive bias an d the precipitable water derived from the satellite data exhibited a negati ve bias. The NCEP reanalysis is able to depict the mean annual cycle of bot h the cross equatorial flow and moisture flow into the Indian subcontinent during the monsoon season, but it fails to depict these differences during excess (1983, 1988, 1994) and deficit monsoon (1982, 1986, 1987) composites . Further, it is seen that inter hemispheric flow far exceeds the excess mo isture available over the Arabian Sea indicating that it is the cross equat orial flow which decides the fate of the summer monsoon.