Bob Alex Ogwang

The Role of Kenya Meteorological Service in Weather Early Warning in Kenya

Early warning in weather forecasting entails provision of timely and effective weather information that allows individuals, organisations, or communities exposed to likely weather hazards to take action that avoids or reduces their exposure to risks. Various sectors have developed different ways to mitigate the effects of climate anomalies. The study reviews the existing monitoring and response structures, and communications flow channels of weather data at different levels, focusing on the role of Kenya Meteorological Service (KMS). The methodology employed was literature review of various documents. The study argues that early warning and weather information communication are essential elements for effective governance of weather risks through a well-developed warning system. At the end, the study recommends strengthening the existing structures with respect to weather monitoring, processing, and dissemination of weather products to end users.

Diagnosis of the 2010 DJF flood over Zambia

This study diagnoses the circulation anomalies associated with the 2010 December–February (DJF) flood in comparison with the 1992 DJF drought over Zambia. Monthly precipitation data for 39 meteorological stations were sourced from Zambia Meteorological Department, the Climate Research Unit precipitation data, and reanalysis datasets are used. Composite analysis was employed to understand the circulation anomalies during the period under review. Results show that the average precipitation over Zambia was above normal; however, some parts of the country received normal rainfall. The climatology of zonal wind is characterized by easterly flow except at low level. During the flood year, this flow was enhanced as observed in the anomalous vertical cross section of the zonal wind; a reversed flow was observed during the drought year. The region was characterized by rising motion during the flood year, which is associated with convergence at low level and divergence at upper level, as opposed to the drought year which exhibited sinking motion. Convergence at low level leads to vertical stretching, whereas divergence at low level leads to vertical shrinking, which suppresses convection due to subsidence. The observed atmospheric circulations can be monitored in the update of seasonal weather forecast to avert the losses associated with floods in future.

Relationship between the North Atlantic Oscillation Index and October-December Rainfall Variability Over Kenya

Rainfall performance and variability are the major problems that affect many socio-economic activities in Kenya. This study investigates the relationship between the North Atlantic Ocean Oscillation (NAO) Index and October – December (OND) rainfall variability over Kenya. Rainfall, wind, geopotential height, temperature, moiture transport and NAO Index (NAOI) values for the period 1961 - 2010 are investigated. The region experiences rainfall that is highly variable in space and time; with the country generally experiencing bimodal rainfall. There is an insignificant negative correlation between the OND rainfall and NAOI over most parts of the country except for the Lake Victoria region that experiences significant correlation at 90% significance level. The study recommends further research on how the NAOI can be used as a predictor for OND seasonal rainfall over the lake region.