TRACER-INP

Ice Nucleation Measurements during TRACER

1 June 2022 - 30 September 2022

Lead Scientist: Sarah Brooks

Observatory: AMF (ARM Mobile Facility 1) - HOU

In this project we will quantify concentrations of aerosols from various sources in the Houston area and their ability to act as ice nucleating particles (INPs). To achieve this goal, aerosol samples will be collected using impactors at AMF1 and the ancillary site, and delivered to Texas A&M for offline INP analysis. Through a complementary project (Targeted Mobile Measurements to Isolate the Impacts of Aerosols and Meteorology on Deep Convection by Anita D. Rapp, Christopher Nowotarski, and Sarah D. Brooks), similar samples will be collected onboard the Texas A&M research trailer. At Texas A&M, the immersion nucleation behavior of aerosol samples will be tested using the Ice Microscope apparatus we designed and have used for a number of previous studies. The fraction of the aerosol population frozen as a function of temperature will be reported for 6-hour samples collected during TAMU deployment days within the TRACER intensive sampling period, June 1–September 30, 2021. Collectively, our data will generate a spatial map of INP activation temperatures and concentrations throughout the Houston area. These measurements will be used to understand the role of ice-forming aerosols in the inflow layer of deep storms in different types of air masses present in the Houston region, and how variations in aerosol concentrations and ice nucleating properties influence convective storms.