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Comparison of TRACER and GoAmazon Deep Convective Clouds with Respect to Urban Aerosol Load

Active Dates 9/1/2023-8/31/2026
Program Area Atmospheric System Research
Project Description
Comparison of TRACER and GoAmazon Congestus and Deep Convective Clouds with Respect to Urban Aerosol Load
Hannah C. Vagasky, Atmospheric and Environmental Research (AER) (Principal Investigator)
Elizabeth Berry, Atmospheric and Environmental Research (AER) (Co – Investigator)
Jiwen Fan, Pacific Northwest National Laboratory (PNNL) (Unfunded Collaborator)

Aerosols have been known to influence convection for over fifty years. However, aerosol-cloud interactions (ACI) are complex, and our understanding is far from complete, especially concerning deep convection. We simply do not currently have the knowledge necessary to adequately represent and validate deep ACI in models.

Clarifying ACI macrophysical impacts is the first step in appropriately representing these processes in weather and climate models. We need first to understand how a cloud’s size, depth, and precipitation characteristics systematically change under different aerosol conditions so that we can appropriately validate results when ACI microphysical processes are added to a model. Additionally, we must look beyond individual case studies. It is essential that we understand ACI at regional or global levels so that we can gain an understanding of the large-scale physical relationships that are necessary for global parameterizations and models.

Previous regional or global ACI studies largely relied on model or satellite data, and many did not adequately control for environmental variability, which can have an impact as large or greater than aerosols. These studies also mainly analyzed aerosol impacts on precipitation, drop size distribution, and cloud top temperature. Other important characteristics such as cloud depth, convective area, and cloud lifetime have not been extensively compared regionally or globally. 

Two recent Atmospheric Radiation Measurement (ARM)-funded field campaigns were focused on increasing our understanding of ACI and had remarkably similar observations: Observations and Modeling of the Green Ocean Amazon 2014–2015 (GoAmazon) and TRacking Aerosol Convection Interactions Experiment (TRACER). This project will:
Use ARM data from TRACER and GoAmazon to classify convective cases by urban aerosol load while controlling for the environment,
Identify and compare how the macrophysical characteristics of congestus and deep convection, and their associated precipitation, change with urban aerosol load in the tropics and sub-tropics, and
Investigate the GoAmazon and TRACER data for evidence of convective invigoration and determine how it impacts precipitation.

The study will be a step toward identifying fundamental aerosol, cloud, and precipitation relationships near urban areas that will ultimately assist with model validation across large regions. This study will specifically address several of ASR’s scientific goals of increasing understanding “of processes that are both fundamental to the Earth’s radiative balance and/or hydrologic cycle and are currently poorly represented in cloud-resolving, regional, and/or global models”, “precipitation formation and intensity”, and “aerosol-cloud interactions such as the influence of aerosol particles on cloud…macrophysics”.
Award Recipient(s)
  • Atmospheric and Environmental Research, Inc. (PI: Vagasky, Hannah)