Spatial/Temporal Distribution of Rainfall and the Dynamic Factors Associated over African Great Lakes Region from 1981 to 2016
Based on Global Precipitation Climatology center (GPCC) precipitation data and Era-Interim Zonal and Meridional wind, relative humidity, Sea Level Pressure and Sea surface temperature data from ECMWF, Statistical methods were conducted to find out the interannual variability of rainfall and its dynamic factors in AGLR from 1981 to 2016. The results show that there are two (long and short) rainfall seasons over AGLR, MAM and OND respectively. The empirical orthogonal function was used to reveal through the dominant principal components (PC1) of the first EOF, the extreme years (wet and dry) for both MAM and OND. Since previous analysis have shown that OND rainfall has high variability than the long rainy season MAM, further analysis (composite analysis) was conducted to investigate the dynamic factors behind the extreme (wet and dry) years for OND season. Results of composite analysis suggest that the Indian Ocean SST regulates the precipitation over the study area; warm SST influences the wind circulation resulting in an upward motion of warm air due to convergence of wind during wet years and the contrary is observed during dry years.
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