What drives daily precipitation over the central Amazon?



Biscaro, Thiago — National Institute for Space Research (INPE)

Area of research:

Cloud Processes

Journal Reference:

Biscaro T, L Machado, S Giangrande, and M Jensen. 2021. "What drives daily precipitation over the central Amazon? Differences observed between wet and dry seasons." Atmospheric Chemistry and Physics, 21(9), 10.5194/acp-21-6735-2021.


We offer an alternative presentation regarding how diurnal precipitation is modulated by convective events that developed over the central Amazon during the preceding nighttime period.


We suggest that there are two distinct modes driving diurnal precipitating convective clouds over the central Amazon. In the wet season, local factors such as turbulence and nighttime cloud coverage are the main controls of daily precipitation, while dry-season daily precipitation is modulated primarily by the mesoscale convective pattern. Therefore, models and parameterizations must consider different formulations based on the seasonal cycle to correctly resolve convection.


Local surface-based observations of cloud occurrence, soil temperature, surface fluxes, and planetary boundary-layer characteristics are coupled with satellite data to identify the physical mechanisms that control the diurnal rainfall in central Amazonia during the wet and dry seasons. This is accomplished through evaluation of the atmospheric properties during the nocturnal periods preceding raining and non-raining events. We use data collected during the Observations and Modelling of the Green Ocean Amazon (GoAmazon 2014/15) field campaign that took place from 1 January 2014 to 30 November 2015 in the central Amazon.