Analyses of Atmospheric Radiation Measurement (ARM) program's Enhanced Shortwave Experiment (ARESE) multiple data sets for studying cloud absorption

Following the Atmospheric Radiation Measurement (ARM) Enhanced Shortwave Ex periment (ARESE), some studies reported a cloud absorption anomaly (CAA) of unprecedented magnitude. The largest discrepancy was found on a heavy over cast day (October 30, 1995) when cloud absorptance inferred from aircraft o bservations was 37% of the incoming solar irradiance, almost twice that of model calculations. The essential measurements supporting the finding were made with an airborne total solar broadband radiometer (TSBR), A thorough a nalysis is performed here, employing a variety of observations from more so urces including aircraft, spacecraft, and ground-based instruments. It is f ound that albedos measured with the TSBR are systematically less than those inferred from other instruments, The difference in mean albedo between TSB R and that inferred from the scanning spectral polarimeter (SSP) on board t he same aircraft amounts to 0.15, which is comparable to the reported CA. S SP data were validated by (1) comparing them to data from the total direct diffuse radiometer (TDDR) spectral radiometer, (2) comparing the SSP's albe do-transmittance slope with that derived from ScaRaB satellite data, and (3 ) comparing SSP-derived albedos with those inferred from cloud optical para meters estimated from ground-based passive and active observations. All the se comparisons show that SSP data are consistent with other measurements wi thin the data uncertainties whose accumulated upper limit is <0.06. A reaso nable doubt is thus cast on the claim of a very strong cloud absorption ano maly found using TSBR data on October 30.