On the spatio-temporal variations of the tropopause height over india and indian summer monsoon activity
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The spatio-temporal variation of the tropopause height (TH) over the Indian region (5°N-35°N, 70°E-95°E) has been studied using monthly mean TH data, for 22-year period, 1965 to 1986. The study revealed that the stations south of 20°N showed maximum TH in April/May and minimum in September. This variation in TH has been attributed to the corresponding variation of average sea surface temperature (SST) over ±20° latitudinal belt over Indian Ocean, Arabian Sea and Bay of Bengal. Further the stations north of 20°N showed maximum in June and minimum in October/November. This maximum in TH has primarily been attributed to the increased insolation and convection. Furthermore it is noticed that the anomaly of TH moved northwards during the period April to July.
The interannual variability of the Indian Summer Monsoon Activity (ISMA) has been studied in relation to all India mean TH (at 12 GMT) for six months April through September. The composites of mean TH for good and bad monsoon years showed that all India mean TH is statistically higher in good monsoon years than in bad monsoon years. The relationship between ISMA and all India mean May TH has been studied using the contingency table. The study suggested that the forecast of ISMA could be prepared using mean May TH.
Key wordsTropopause height Indian monsoon activity
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