Lake-effect rains over Lake Victoria and their association with Mesoscale Convective Systems

Abstract This article examined rainfall enhancement over Lake Victoria. Estimates of over-lake were compared with in the surrounding lake catchment. Four satellite products initially tested against estimates based on gauges or water balance models. These included TRMM 3B43, IMERG V06 Final Run (IMERG-F), CHIRPS2, and PERSIANN-CDR. There was agreement among for catchment but a large disparity them rainfall. IMERG-F clearly an outlier, exceeding estimate from 3B43 by 36%. The overestimation likely related to passive microwave assessments strong convection, such as prevails Overall, showed best "ground truth" used further analyses. Over-lake found be enhanced all months. During March-to-May long rains varied between 40% 50%. October-to-December short 33% 44%. Even during two dry seasons at least 20% 50% some While magnitude month month, seasonal cycle essentially same rainfall, suggesting that dominant influence is large-scale environment. association Mesoscale Convective Systems (MCSs) also evaluated. similarity spatial patterns MCS count each suggested these produced major share lake. Similarity interannual variability supported this conclusion.