Collaborative Research: Characterizing interactions between tropical deep convection and the environment using a buoyancy framework

Tropical convective storms play a significant role in global weather and climate. With current computing technology, it is impossible to directly model all aspects of convection, so scientists rely on parameterizations, which are approximations that are coded into the models. Simulations of Earth’s climate are particularly sensitive to the parameterizations of tropical convection, so it is incumbent on the scientific community to improve understanding of tropical convection to improve the parameterizations that go into weather and climate modeling.

In this project, the research team plans to study how tropical convection interacts with its surrounding environment using a new framework that focuses on the entrainment of air near the Earth's surface into the storm. In addition to the potential to improve numerical modeling, the research team will organize a workshop to bring together the tropical convection research community, including a diverse set of early-career scientists and students.

The overarching goal of this project is to continue work towards identifying a conceptual model for tropical deep convection that can be used to explain precipitation variability across scales. The research team will build upon the “precipitation-buoyancy (P-B) framework” which relates precipitation and estimates of entraining plume buoyancy. The research team will center their work around two main research questions: (1) to what extent do “grid-scale” O(100 km) integrated measures of convective instability accurately assess the capacity of the atmosphere to support deep convection, and (2) how can we refine grid-scale average instability measures to account for variability and dynamics across scales?

The investigators will use new mesoscale convective tracking databases, cold pool gradient feature detection algorithms, long-standing radar data, field campaign data, and satellite observations, combined with novel compositing techniques to address the following objectives:

1. Characterize how the precipitation-buoyancy (“P-B”) relationship varies as a function of convective variability across spatial scales.

2. Examine how P-B thresholds change as a function of mesoscale convective system evolution, estimating the sensitivity of deep convection to its thermodynamic environment throughout different lifecycle stages.

3. Characterize how dynamical interactions - mass flux/entrainment, wind shear, vorticity, cold pools - modify thermodynamic controls on deep convective evolution.

4. Apply the refined P-B framework to study diurnal, regional, and intraseasonal precipitation variability across the tropics.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.