Quantitative role of far-infrared emission on diabatic forcing of the middle and upper troposphere in clear and cloudy conditions

摘要

The clear sky radiative energy balance in the infrared spectrum is investigated with particular attention to the role of water vapour pure rotational band in the spectral range 10-600 cm~(-1). Main results for Tropical and Sub Artie Winter atmospheres are in good agreement with those previously reported by other authors. Multiple scattering layers, simulating the presence of cirrus clouds, are used in Tropical atmosphere. The cloudy tropospheric heat balance is studied by the introduction of spectral power densities instead of spectral heating rates. Distribution of radiant energy between air molecules and cloud ice crystals is taken into account and the effects of cirrus absorption and scattering are distinguished. Finally a comparison between Mie and Fu parameterization is performed to understand the effects of more realistically shaped cirrus partieles.