Summary of Abstract Submission

Abstract Submission No. IO50-05-0051PresentationPoster

DIURNAL CYCLE OF PRECIPITATION OVER INDIAN OCEAN

D Rajan*1

1 NCMRWF, Ministry of Earth Sciences, Noida, UP, India

ABSTRACT :

The Indian summer monsoon is an important part of the boreal summer monsoon covering south and south East Asia. In this study we examine both the intensity and frequency of rainfall estimated from the space-based observation and the precipitation predicted by the global models those are operational at the National Centre for Medium Range Weather Forecasting (NCMRWF). Over the Indian Oceanic region the Tropical Rainfall Measuring Mission (TRMM) satellites with the precipitation radar and the microwave imager; estimation of rainfall are available over a shorter time resolution. During the monsoon 2014 over most of the North Indian Ocean the hour of maximum precipitation is between 03 and 09 UTC and is almost equally distributed around the local noon. Over the Arabian Sea, there is a spatially coherent pattern in the mode of the peak at 09 UTC, whereas over the Bay of Bengal it is 06, 09 and 12 UTC. The hour of maximum precipitation computed from the model forecasts amounts indicates the early release of convective instability and precipitation in the models compared to that observed in the atmosphere. In the equatorial Indian Ocean, while most of the western parts show a late night/early morning peaks. During the monsoon, westerly winds prevail along the west coast of India and their interaction with the land breeze leads to maximum precipitation at late night/early morning hours. Occasionally, convective cells forming over sea drift inland under suitable synoptic wind conditions leading to a maximum in precipitation in the early morning. Also, over the sea areas away from the coast, the hour of maximum precipitation occurs at the time of maximum relative humidity close to noon time. The above results will also be examined for the monsoon 2015.