Targeted Mobile Measurements to Isolate the Impacts of Aerosols and Meteorology on Deep Convection

Abstract

One of the main goals of the upcoming Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Tracking Aerosol Convection Interactions Experiment (TRACER) field campaign near Houston, Texas is to improve understanding of meteorology and aerosol effects on deep convective storms. Houston summertime storms are often initiated and organized by the local sea- and bay breeze circulations and may be modified by urban heat island effects. The distribution of aerosols may be very different across these different airmasses. To isolate and understand the roles of meteorology and aerosols on these storms, simultaneous measurements in these different airmasses are required. To help TRACER achieve this goal, we will supplement the fixed-site ARM observations by deploying the fully mobile Texas A&M University measurement facility which carries instruments capable of measuring aerosol and atmospheric properties that can be moved to multiple locations on a given day. The main scientific goal of this project is to use these surface and vertical profile measurements with ARM site measurements to understand how the distributions of cloud droplet-forming and ice-forming aerosols correspond to the inflow layer of deep storms in different types of air masses present in the Houston region, and how these variations influence storm properties. Thus, our mobile sampling platform is expected to significantly enhance the scientific impact of ARM’s TRACER campaign.

In conjunction with the ARM site measurements, we will use the Texas A&M mobile facility measurements to first quantify the ability of the complex aerosols populations in the Houston area to form cloud drops or ice particles.  Since comparable measurements are available at both the ARM sites and in the Texas A&M mobile facility, we will further use these measurements to develop both vertical profiles and spatial maps of both aerosols and meteorological properties (temperature, humidity, winds) in different airmasses across sea and bay breeze fronts.  Combining our derived profiles with ARM radar measurements, we will determine how relevant storm properties such as updraft size, intensity, and rainfall relate to changes in aerosol concentrations and meteorological conditions in convective inflow layers captured by our measurements. To isolate the influences of aerosols from the meteorological environment, we will use the measured aerosol and meteorological environment profiles in idealized numerical simulations to disentangle the effects of meteorology from aerosol-cloud interactions on deep convective storm properties. This project is expected to help reduce current uncertainties in our knowledge of aerosols and meteorology important for understanding the interactions between aerosols and clouds in deep convective storms and will provide an important data set we expect to be widely used by the scientific community.