Cloud liquid-water profile retrieval algorithm and validation

摘要

In the first stage of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A/Humidity Sounder for Brazil (AIRS/AMSU/HSB) geophysical retrieval algorithm, cloud liquid-water profiles are retrieved from the microwave measurements. These profiles are used in the forward radiative-transfer calculation for microwave channels in subsequent retrieval steps. The retrieval of cloud liquid water is based on a model for moisture condensation in which the relative humidity for onset of clouds is a retrieved parameter, which makes the retrieval more robust with respect to errors in the retrieved temperature profile and horizontal inhomogeneities of the moisture field within an instrument footprint. Retrieved cloud liquid is compared with ground-based radiometric measurements, and the vertical distribution is compared to relative humidity profiles from dedicated radiosondes launched underneath the Aqua satellite.