Recent trends in summer temperatures over the North Indian Ocean

Trends in sea and air temperatures over the North Indian Ocean (Equator to 20 degrees N) during summer (May) have been examined. The trend analysis re veals that both sea surface temperature (SST) and air temperature have regi stered significant increasing trends during the period 1961-86. The trend i n SST during 26 years' period ranges from 0.4 degrees C to 0.8 degrees C an d that in air temperature ranges from 0.6 degrees C to 0.7 degrees C. Power spectrum analysis shows a significant El-Nino/Southern Oscillation (ENSO) scale cycle (2-5 years) in SST and air temperature variations. The frequenc y of cyclonic disturbances (depressions and cyclones) has shown a significa nt decreasing tendency during 1961-86.