Preliminary Spectral Infrared Analysis of a cirrus cloud based on ARIES interferometric measurements

An estimation of errors found in simulating interferometric measurements above ice clouds and a theoretical investigation on the impact of cloud features on measured and retrieved quantities is given. The database consists of spectra recorded by ARIES (Airborne Research Interferometer Evaluation System). Multiple scattering line by line simulations are compared to measured radiances accounting for the instrumental error associated with the measurement (total noise) and spatial variability of the meteorological and microphysical properties. The theoretical investigation involves the computations of net fluxes at all levels in order to define the atmospheric diabatic heating and energy balance found when different geometrical configurations are assumed. It is demonstrated that cloud layers with different thickness (same cloud top elevation and different cloud depth) but keeping ice water content (IWP) constant, can produce similar radiometric signals in the upwelling radiance and fluxes.