Momentum transport of wave zero during March: A possible predictor for the Indian summer monsoon

Journal of Earth system science

S M Bawiskar1¹  S S Singh1¹  V R Mujumdar1¹ 

[1] Indian Institute of Tropical Meteorology, Pune 411 008$$

关键词: Momentum transport;    zonal waves;    zone of westerlies;    Indian monsoon rainfall.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Analysis of monthly momentum transport of zonal waves at 850 hPa for the period 1979 to 1993, between 30°S and 30°N for January to April, using zonal (𝑢) and meridional (𝜐) components of wind taken from the ECMWF reanalysis field, shows a positive correlation (.1% level of significance) between the Indian summer monsoon rainfall (June through September) and the momentum transport of wave zero TM(0) over latitudinal belt between 25°S and 5°N (LB) during March. Northward (Southward) TM(0) observed in March over LB subsequently leads to a good (drought) monsoon season over India which is found to be true even when the year is marked with the El- Nino event. Similarly a strong westerly zone in the Indian Ocean during March, indicates a good monsoon season for the country, even if the year is marked with El-Nino. The study thus suggests two predictors, TM(0) over LB and the strength of westerly zone in the Indian Ocean during March.

【 授权许可】

Unknown