The investigation of cloud properties using coincident wideband dual-altitude TOGA-COARE observations

A study of TOGA-COARE data used to estimate microphysical cloud information is described. Coincident wideband passive microwave brightness temperature observations from radiometers on both the DC-8 aircraft (~11 km altitude) and the ER-2 aircraft (~20 km altitude) are used to investigate microphysical cloud profile conditions between the two aircraft. A wideband, nadir-viewed, dual-altitude comparison between TOGA-COARE brightness temperature (T_B) observations and computed brightness temperature values is the basis for the estimation procedure. A flexible radiative transfer model was used to compute wideband, nadir-viewed dual altitude T_B values for a variety of microphysical cloud conditions. By varying the microphysical cloud parameters (e.g., particle size distributions and the hydrometeor density) and requiring that the comparisons remain consistent with the TOGA-COARE observations, the cloud conditions between the two aircraft can be estimated