Summary of Abstract Submission

Abstract Submission No. IO50-10-0028PresentationOral

MARINE WEATHER FORECASTING OVER SOUTHERN INDIAN OCEAN AND ITS VALIDATION

Anitha Gera*1, D. K. Mahapatra2, Kuldeep Sharma2, Satya Parakash2, Mitra A K2, G Iyengar2, Rajagopal E N2

1 NCMRWF,ESSO,MoES,NOIDA, INDIA
2 NCMRWF, INDIA

ABSTRACT :

ESSO, NCAOR conducts expeditions over Indian Southern Ocean(SO) to pursue research addressing Hydrodynamics, Biogeochemistry etc. This is augmented by NCMRWF generated global weather forecasts using assimilative global & mesoscale modeling systems. NCMRWF participated and issued daily, real-time five day weather forecasts (eg: wind, rainfall, MSLP) during the southern ocean expedition carried out by NCAOR during Dec2014 to Feb2015. These fields are validated and it is found that the model is able to well reproduce the 3 climatological bands of the region of interest viz., trade winds, mid latitude highs and the subpolar lows till 120h lead time. Forecasting extreme conditions of weather during the period with high reliability is crucial. Six cyclonic disturbances occurred during the period. The model performed well during such events ( eg: Bansi-cat4, Eunice-cat5) and could satisfactorily pick up the position and intensity of the cyclones 3-5 days in advance so as to issue forewarning to the cruise. The model forecasts of wind speed, air-temperature, MSLP are validated against ship AWS and satellite rainfall and showed very good agreement. The RMSE of 10m winds is within 2 ms-1 and rainfall 1cm till 120h lead time. The phase and magnitude of eastward propagations of the rainfall are well reproduced. It is observed that the model field RMSD increase marginally with increasing lead time. Hence the NCMRWF model wind and flux fields are also highly suitable to force ocean models to study hydrodynamics, ocean currents MLD, eddies, air-sea-ice interaction, etc over the southern ocean.