Preprints
https://doi.org/10.5194/egusphere-2023-2697
https://doi.org/10.5194/egusphere-2023-2697
12 Dec 2023
 | 12 Dec 2023

Environmental Controls on Isolated Convection during the Amazonian Wet Season

Leandro Alex Moreira Viscardi, Giuseppe Torri, David Kenton Adams, and Henrique de Melo Jorge Barbosa

Abstract. The Amazon rainforest is a vital component of the global climate system, influencing the hydrological cycle and tropical circulation. However, understanding and modeling the evolution of convection in this region remains a scientific challenge. Here, we assess the environmental conditions associated with shallow, congestus, and isolated deep convection days during the wet season (December to April) employing measurements from the GoAmazon (2014–2015) experiment and large-scale wind field from the constrained variational analysis. Composites of deep days show moister than average conditions below 3 km early in the morning. Analyzing the water budget at the surface through only observations, we estimated the water vapor convergence term as a residual of the water balance closure. Convergence remains nearly zero during the deep days until early afternoon (13 LST), when it becomes a dominant factor in their water budget. At 14 LST, the deep days experience a robust upward large-scale vertical velocity, especially above 4 km, which supports the shallow-to-deep convective transition occurring around 16–17 LST. In contrast, shallow and congestus days exhibit preconvective drier conditions, along with diurnal water vapor divergence and large-scale subsidence that extend from the surface to the lower free troposphere. Moreover, afternoon precipitation exhibits the strongest linear correlation (0.6) with large-scale vertical velocity, nearly double the magnitude observed for other environmental factors, even moisture at different levels and periods of the day. Precipitation also exhibits a moderate increase with low-level wind shear, while upper-level shear has a relatively minor negative impact on convection.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Leandro Alex Moreira Viscardi, Giuseppe Torri, David Kenton Adams, and Henrique de Melo Jorge Barbosa

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2697', Kyle F. Itterly, 30 Dec 2023
  • RC2: 'Comment on egusphere-2023-2697', Anonymous Referee #2, 19 Feb 2024
Leandro Alex Moreira Viscardi, Giuseppe Torri, David Kenton Adams, and Henrique de Melo Jorge Barbosa
Leandro Alex Moreira Viscardi, Giuseppe Torri, David Kenton Adams, and Henrique de Melo Jorge Barbosa

Viewed

Total article views: 398 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
265 101 32 398 17 17
  • HTML: 265
  • PDF: 101
  • XML: 32
  • Total: 398
  • BibTeX: 17
  • EndNote: 17
Views and downloads (calculated since 12 Dec 2023)
Cumulative views and downloads (calculated since 12 Dec 2023)

Viewed (geographical distribution)

Total article views: 435 (including HTML, PDF, and XML) Thereof 435 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 12 Jun 2024
Download
Short summary
We evaluate the environmental conditions that control how clouds grow from fair weather cumulus to severe thunderstorms during the Amazonian wet season. Days with rain clouds begin with more moisture in the air and have strong convergence in the afternoon, while precipitation intensity increases with large-scale vertical velocity, moisture, and low-level wind. These results contribute to understanding how clouds form over the rainforest.