Prior to the ARM Enhanced Shortwave Experiment (ARESE), models had included field measurements with enhanced absorption that caused scientists to question ideas surrounding the absorption of solar radiation in the cloudy atmosphere. ARESE sought to understand the interactions between solar energy and clear and cloudy skies in order to gain knowledge about these enhanced absorption measurements and to improve modeling for the absorption of solar radiation. The Department of Energy and NASA collaborated on ARESE over a five-week period from September 25th, 1995, to November 1st, 1995 from a central facility in North Central Oklahoma. The twelve science flights collected approximately 60 hours of in-flight data in a variety of atmospheric conditions to create an extensive dataset.
ARESE developed two science objectives to address the mission purpose of improving the understanding of the absorption of solar radiation in the cloudy atmosphere. The first objective was to directly measure the absorption of solar radiation in the clear and cloudy atmosphere. The second objective was to identify and understand absorption causes in models that showed enhanced absorption measurements.
To achieve these objectives, three aircraft flying simultaneously at different altitudes collected measurements of the upwelling and downwelling of radiative fluxes. The instrumented NOAA Twin Otter aircraft flew at 1,500-5,000 feet, while the high-altitude manned Egrett aircraft flew at 43,000 feet, and the NASA ER-2 flew over the Egrett at 65,000 feet (though it did not stay in constant alignment with the Egrett due to its high speed capability). All three of these aircraft were equipped with “valero” radiometers, and the aircraft were flown over radiometers at the ARM Clouds and Radiation Testbed (CART) central facility. Radar, lidar, and multispectral measurements were captured at CART and at extended facilities associated with the ARM Southern Great Plains site. The aircraft and surface facilities together were used to measure water vapor profiles, aerosol optical depths, cloud structure and ozone profiles, and to conduct cloud forcing experiments under varying conditions. Additionally, scientists used these platforms to obtain column absorption, surface albedo, and flux profiling measurements for clear skies. Satellite observations complemented these airborne and ground-based data. These satellite observations were used in calibration experiments by the ER-2, in which spectral radiance measurements from the MODIS Airborne Simulator were used to calibrate radiance measurements from the GOES satellite.
The ASDC houses measurements conducted during ARESE from instruments aboard the NASA ER-2 aircraft.