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Abstract Heterogeneous landscapes can influence the development of convection through the generation of thermally driven mesoscale circulations. To assess the impacts of these circulations and their interaction with sea breezes, we simulated convection in an idealized coastal environment using the Regional Atmospheric Modeling System (RAMS). We compared simulations with striped patterns of surface vegetation to those of uniform vegetation to identify the importance of vegetation heterogeneity in impacting convective development. Under dry soil conditions representative of those during the Tracking Aerosol Convection Interactions Experiment (TRACER) and Experiment of Sea Breeze Convection, Aerosols, Precipitation, and Environment (ESCAPE) campaigns in June 2022, we found that these vegetation-induced circulations, referred to in the literature as “forest breezes,” are more important than the sea breeze in determining the location of convection initiation. Convection and precipitation are also found to be favored over forests and suppressed over pasture and suburban landscapes as a result of greater surface sensible heat flux over the forest. Our findings also indicate that forest breezes are important for initiating convection along the boundaries of the forest, but that cold pools may play a key role in propagating the forest breezes toward the center of the forest stripe. In our simulations, the collisions of these breezes in the center of the forest stripe lead to uplift and strong convection there; however, a different width of the forest stripe would alter when the forest breezes collide or whether they collide at all. The presence of these cold pools may therefore impact the “ideal stripe width,” the width of each vegetation stripe which maximizes domain-wide precipitation.
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This content will become publicly available on February 1, 2027
Cold Pools Reduce the Impacts of Deforestation on Convection Initiation
ABSTRACT The individual and synergistic impacts of cold pools and land surface heterogeneity on convection initiation are investigated. Idealized large eddy simulations of deep convection over the Amazon rainforest are conducted. Simulations test realistic and homogenized vegetation, along with realistic and suppressed low‐level evaporation which eliminates cold pools. Updrafts are tracked to determine convection initiation locations. The aggregation of initiation locations is quantified with an organization index. Initiation locations are randomly distributed over homogeneous vegetation, with or without cold pools, demonstrating that cold pools have minimal impacts on initiation locations over homogeneous vegetation. With realistic vegetation, convection initiation is more frequent over forested than deforested areas due to favorable thermodynamics. Heterogeneous vegetation effectively aggregates initiation locations and precipitation compared to homogeneous vegetation, whereas cold pools disaggregate initiation locations and precipitation by propagating into deforested regions and initiating convection. Thus, cold pools partially counteract the effects of anthropogenically driven land surface heterogeneity.
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- Award ID(s):
- 2029611
- PAR ID:
- 10679621
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Atmospheric Science Letters
- Volume:
- 27
- Issue:
- 2
- ISSN:
- 1530-261X
- Page Range / eLocation ID:
- e70011
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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