The Impact of Lake Victoria on the Convective Activities over the Kenya Highlands

抄録

 A three-dimenstional numerical model incorporating cumulus parameterisation scheme is used to investigate the impact of Lake Victoria breeze on the initiation and development of the convective activities over the Kenya highlands. This mesoscale model is in flux form and has 37 grid points in the x-direction, 25 grid points in the y-direction and 13 vertical σ-levels. The model is nested with horizontal resolution of the fine mesh of 40 km and of coarse mesh of 120 km. The model is formulated for an equatorial atmosphere where the Coriolis parameter f∼0.
 Two experiments are conducted using the model. The first experiment excludes the lake while the second experiment includes the lake in the runs.
 Results show that there is stronger flow and hence a resulting stronger covergence in the lower layers above the highlands in the second experiment than in the first experiment. It is found from these results that on the average the results from experiment 2 show that the lower atmosphere above the highlands is more moist by 2 g/kg and warmer by 5°C than that shown by results from experiment 1. The precipitation was increased by about 1.2 cm in the day-time over the highlands. The overall condesnational heating was found to increase by 5°C/day. These results suggest that Lake Victoria is a major source of energy and moisture which are both responsible for the strong conventive activities over the Kenva highlands.