| Description |
Rainfall event duration, rain rate, and rainfall accumulation are derived using NASA 3B42 and IMERG satellite rainfall retrievals over the deep tropics. Monthly 99thpercentile rainfall event characteristics are matched to large-scale, monthly mean total column water vapor (TCWV) and 500-hPa vertical motion (omega) from ERA-Interim and MERRA-2 reanalyses. Relationships between TCWV, omega, and these 99th-percentile "extreme" rainfall events are quantified separately for oceans, South America (SA), and Africa using multiple linear regressions. After removing the approximated effect of elevation on extreme rainfall event characteristics over land regions, unique regional relationships between TCWV, omega, and extreme rainfall event characteristics emerge. TCWV is positively correlated with event rainfall over land regions but the event rainfall-TCWV relationship is inconclusive over oceans. In contrast, rising motion has a strong positive correlation with event rainfall over oceans while the event rainfall-omega relationship is inconclusive over land regions. The relative importance of each environmental and surface variable for predicting rainfall event characteristics also varies regionally. Rainfall events over oceans show the largest sensitivity to changes in omega, whereas events over SA and Africa are more sensitive to changes in TCWV and elevation than omega. Over oceans and SA, increases in event rainfall are driven more by longer lasting events than increasing rain rates, whereas the opposite is true over Africa. |
