Open AccessAssociation between mid-latitude circulation and Indian monsoon rainfall
Author(s) -
R. Bhatla,
Joydev Chattopadhyay
Publication year - 1999
Publication title -
mausam
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.243
H-Index - 12
ISSN - 0252-9416
DOI - 10.54302/mausam.v50i1.1802
Subject(s) - climatology , latitude , monsoon , low latitude , perturbation (astronomy) , zonal and meridional , northern hemisphere , atmospheric circulation , geology , geography , environmental science , geodesy , physics , quantum mechanics
The statistical relationship between the summer monsoon rainfall over India and mid-latitude general calculation at the 500 hPa level was investigated for the period 1971-1989. The index used to characterise general circulation feature is the perturbation of the zonal flow (ratio of meridional to zonal index) for the latitudinal band 35°N - 70°N over different geographical area and the hemisphere. It was found that the perturbation of the zonal flow during preceding January over the geographical sector 1 (45°W - 90°E) shows significant relationship with the subsequent Indian summer monsoon rainfall in an inverse manner. Thus, the perturbation of the mid-latitude circulation during preceding January over the geographical sector seems to be a useful predictor of the subsequent Indian monsoon rainfall. Significant simultaneous inverse relationship also exists between perturbation of mid-latitude zonal flow during July to September over Sector 2 (90°E- 160°W) and summer monsoon rainfall over northwest India.