The Department of Energy (DOE) is conducting the Two Column Aerosol Project (TCAP) with several contributions from NASA. TCAP is designed to provide measurements of aerosol composition, size, and optical properties within two columns of air off the coast of North America. The field campaign will deploy ground-based instruments on Cape Cod, Massachusetts for a 12-month period starting in the summer of 2012, supplemented with intensive aircraft observation periods in summer and winter using the ARM Aerial Facility’s Gulfstream-1(G-1) research aircraft. Our new airborne Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) has been selected for flight on the G-1 in TCAP.

4STAR will directly yield atmospheric direct-beam transmittance, leading to aerosol optical depth and extinction between the G-1 stair-step segments. In addition, 4STAR's full spectral measurements are expected to provide improved retrieval of trace gases, and 4STAR's sky-scanning measurements will enable retrievals of size distribution, complex refractive index, and shape, analogous to retrievals from the ground-based AERONET sun-sky photometers.