Preparing for a coordinated research flight, the Gulfstream-1 and NASA King Air B-200 stay cool on the ramp, while immediately behind them, the NOAA Twin Otter taxis out to the runway. Photo courtesy of Rahul Zaveri.
Preparing for a coordinated research flight, the Gulfstream-1 and NASA King Air B-200 stay cool on the ramp, while immediately behind them, the NOAA Twin Otter taxis out to the runway. Photo courtesy of Rahul Zaveri.
June 28 marked the last official day of data collection for the month-long Carbonaceous Aerosol and Radiative Effects Study (CARES) based out of Sacramento, California. During the campaign, the ARM Aerial Facility coordinated 21 science flights by the Gulfstream-1 (G-1) aircraft, obtaining aerosol data from 67.4 research hours over the study region and instrumented ground sites. NASA flew a King Air B-200 in coordination with the G-1 for almost every flight, and also sampled areas outside of the G-1’s primary domain to supplement the data set. In addition, the NOAA Twin Otter shifted its CALNEX operations to Sacramento from June 15 through 28 to further enhance the collaborative data set of urban aerosols.

More than 60 scientists from a dozen institutions participated in the campaign to obtain a variety of measurements from instruments on the aircraft and at the two ground sites. The instruments gathered trace gas, aerosol, and meteorological measurements that will allow researchers to investigate the ways in which atmospheric aerosols and their climate-affecting properties evolve as they travel and age. Included among the instruments were several new ones procured through the American Recovery and Reinvestment Act of 2009. The future performance of these new instruments will greatly benefit from their testing and inter-comparison in a rigorous field setting.

A new ultra-high sensitivity aerosol spectrometer measures atmospheric aerosol particles in the range of 55 to 1000 nanometers.  It records the size and time of each particle sampled.
A new ultra-high sensitivity aerosol spectrometer measures atmospheric aerosol particles in the range of 55 to 1000 nanometers. It records the size and time of each particle sampled.
Ending on a ‘high note,’ the highest ozone and aerosol concentrations of the entire study were recorded on the last day. Data from that day showed a distinctive plume over the city, bounded by all flight legs. Instruments in the G-1 recorded a high concentration of benzene in the plume, with the same spike picked up by ground instruments near I-80 at American River College. The repeated morning and afternoon flights will provide a good data set studying daily variation and evolution of aerosol properties.

Looking ahead, the CARES and CALNEX science teams have teamed to propose a California field campaign session at the American Geophysical Union 2010 Fall Meeting in San Francisco. The session will cover the two campaigns and other related studies to have a first look at the data from different platforms and campaigns, and promote cross-fertilization of ideas for further analyses.

Data from the CARES campaign will be available in the ARM Data Archive in about six months, after a thorough quality check. Media coverage from the campaign can be found in the CARES news and press page, which highlights the CARES image set, including many photos from Rahul Zaveri’s blog, “Rahul CARES.”