Water‐Vapour Continuum Absorption In the Tropics: Aircraft Measurements and Model Comparisons

Measurements of water‐vapour continuum absorption in the 10‐12 μm window have been made in the tropical atmosphere using a multi‐channel narrow field‐of‐view radiometer mounted on an aircraft. Comparisons with two radiative transfer models (GENLN 2 and LOWTRAN7) are made which show that the model underestimates the absorption by some thirty percent. Two methods of modifying the existing empirical continuum parametrization to obtain better agreement with the aircraft measurements are assessed: one involves increasing the self‐broadened absorption coefficient, the other increasing the temperature‐dependence parameter.