Observations and models of irradiance profiles, column transmittance, and column reflectance during the Atmospheric Radiation Measurements Enhanced Shortwave Experiment

In the fall of 1995 the Atmospheric Radiation Measurement Enhanced Shortwav e Experiment (ARESE) was conducted to address fundamental questions about t he amount of absorption of solar radiation occurring in clear and cloudy sk ies. Irradiances measured from instruments flown on stacked aircraft as par t of this experiment are compared to modeled irradiances for several repres entative days. As a basic check of the data and the model, the downwelling irradiances at 13 km are examined and found to be in good agreement, with b oth model and observations showing day-to-day variations as well as shorter timescale variations due to changing atmospheric conditions. Evidence of c loud-induced enhanced absorption is seen from an analysis of column reflect ance and absorptance as determined from simultaneous measurements made from the stacked aircraft. When compared to model results, profiles of irradian ce versus altitude as measured by one aircraft indicate cloud-induced enhan ced absorption as well.