Implementation of the WRF-3DVAR data assimilation technique over east Africa: a case study of Tanzania

Numerical Weather Prediction (NWP) is a mathematical model of atmosphere and ocean to predict the weather based on current weather conditions. A Weather Research and Forecasting (WRF) model is one of NWP model which was used in this study. 3DVAR- data assimilation technique based on minimization of cost function was applied within WRF model to study the impact of assimilating observations to reduce the uncertainties of the model. A series of single observation tests undertaken to understand and demonstrate the response of each of parameter on the 3DVAR data assimilation in the domain of study. Analysis was done to observe the effects of assimilation by comparing WRF model results before and after data 3DVAR data assimilation. From the wind flow at low level (850hpa) and upper level (200hpa), pressure time series for different stations had clearly showed that 3DVAR data assimilation can help to improve the accuracy of the WRF model hence improve weather forecasts over East Africa region.