Validation of operational wave model WAVEWATCH III against Satellite Altimetry Data over South West Indian Ocean

Abstract: This study represents an attempt to validate WAVEWATCH III® over the coast East African countries. WAVEWATCH III® (Tolman 1997, 1999, 2009) is the third generation wave model used for wave forecasting. One of the greatest challenges face by the Meteorological Departments in the East African countries (Kenya and Tanzania in particular) is to provide accurate and timely marine weather forecast. The Ocean data including observations from Buoys are very scarce over the West Indian Ocean domain. In this research, the satellite altimetry data was used to assess the model to improve the accuracy of the Ocean models used to issue marine forecasts and warning over the region. The WW3 has performed the simulation for different points over South West Indian Ocean domain for the period of one month (June 2014). The statistical results from comparing the altimetry-derived Significant Wave Height (SWH) and those from the Wave model WW3 which is forced by winds input from Global Forecast Systems (GFS) global model shows that the absolute values of mean errors ranged from 0.71 to 3.38 during the period under consideration, the bias values are negative indicating slightly underestimating of modeled wave lengths in comparison with satellite data. Similarly when the WW3 wave model is forced by winds input from European Centre for Medium Range Weather Foresting (ECMWF), shows that the absolute errors are quite small (0.0006 – 0.049) to imply that WW3 gave good forecast if initialized from winds from ECMWF as opposed to GFS, but still slightly underestimating of modeled wave length in comparison with satellite data.

Biography: Mr. Chuki Sangalugembe is the employee of Tanzania Meteorological Authority, currently working at Marine Meteorological Services. Mr. Sangalugembe is the holder of Master of Science in Mathematical modeling, a Postgraduate Diploma in Meteorology and Bachelor of Science (Mathematics and Physics). He is expert in weather and climate modeling and worked at Numerical Weather Prediction section in Tanzania Meteorological Authority for more than fifteen years