TRACERACE

The main objective for the TRACER (Tracking Aerosol Convection Interactions Experiment) campaign is to provide high-temporal-and spatial-resolution observations of convective clouds in the Houston region, over a broad range of environmental and aerosol regimes. The TRACER siting strategy is to deploy the AMF1, with its full suite of cloud, aerosol, precipitation, and atmospheric state measurement capabilities, in a region that experiences the full diversity of aerosol properties from Houston/Galveston area urban, industry, and refinery sources. An ancillary site (ANC) will be deployed during TRACER-ACE in a region that is expected to experience more pristine aerosol conditions, representative of the background atmospheric state for this region, and is the focus of this proposal. During the IOP period (01 June 2021–30 September 2021), continuous aerosol observations will be obtained in the relatively unpolluted region to the southwest of Houston in Brazoria County, Texas. These measurements, in combination with those from the AMF1, will provide an understanding of the variability of aerosols and meteorology between the onshore flow and the urban Houston area. These aerosol measurements include: the CCN number concentration as a function of water vapor super-saturation, the total aerosol number concentration at various cut-sizes (> 1 nm, > 3 nm, > 10 nm) to target the formation of newly formed aerosol, and the total aerosol size distribution from 1 to 500 nm to target the growth of the aerosol. These continuous measurements will address the following scientific objectives: characterization of the aerosol water-uptake and size distribution properties at a “clean” site, assessment of the frequency and strength of new particle formation, and (in conjunction with co-located radiosonde and meteorological observations) identification of the atmospheric conditions and processes that potentially control new particle formation at a site less impacted by urban emissions and pollution.

Timeline