Deep Convective Evolution From Shallow Clouds Over the Amazon and Congo Rainforests. Issue 1 (4th January 2020)

• Record Type: Journal Article
• Authors: Chakraborty, Sudip; Jiang, Jonathan H.; Su, Hui; Fu, Rong
• Is Part Of: Journal of geophysical research. Volume 125:Issue 1(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-04
• Subjects: equatorial African deep convection -- Congo basin rainfall -- Amazon deep convection -- shallow‐deep convection evolution -- deep convection from GPM data -- cloud development; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2019JD030962
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Using satellite measurements from A‐Train constellation and Global Precipitation Measurement mission, we investigate the relationships between the afternoon time shallow convective top height (CTHafternoon ) and the evening time deep convective storm top height (CTHevening ) and rain rate (RRevening ) over the Amazon and Congo regions. We use CloudSat cloud type stratus and stratocumulus as the shallow afternoon clouds. Our results indicate that the afternoon shallow clouds over the Congo region are associated with suppressed and weakened evening time deep convection, whereas shallow clouds over the Amazon region are associated with the growth of the evening time deep convection. Over the Congo region, we find that as CTHafternoon increases, shallow convective rain rate in the afternoon (RRafternoon ) increases. As a result, the evening time convective available potential energy (CAPE) as well as free tropospheric humidity (RH700‐300 ) decrease. Consequently, condensation occurring inside deep convection reduces and CTHevening as well as RRevening decrease over there. Over the Amazon region, however, RRafternoon does not vary significantly with CTHafternoon . As CTHafternoon increases, CAPE, RH700‐300, and condensation occurring inside deep convection increase in the evening. As a result, deep convective CTHevening and RRevening increase with CTHafternoon over the Amazon basin. These dissimilarities in the ambient condition drive the shallow to deep convective evolution differently over these two rainforests. On the other hand, shallow clouds that remain shallow in the evening are associated with less CAPE and RH700‐300, RRafternoon, and RRevening . Although CAPE and RH700‐300 promote deep convection to a height cloud top height, high vertical wind shear inhibits deep convection. Key Points: The afternoon shallow clouds over the Congo region suppress evening deep convection and weaken the evening storm top height and rain rate Shallow clouds over the Amazon region promote growth of the evening deep convective cloud The relationship between afternoon shallow clouds and evening deep convection systems over the Congo and Amazon regions is different