Thermal radiation in Arctic stratus clouds

Infrared radiative properties of Arctic stratus clouds in the 10.1 to 12.7μm wavelength region are determined from a series of aircraft measurements. The average emissivity of the clouds when scattering is neglected is unity for cloud depths greater than 350m. Under the assumption that the cloud layers are homogeneous the cloud droplet volume absorption coefficient is estimated as 17±5km−1. Several mass absorption coefficients are estimated for several assumed liquid water distributions. It is also concluded that the cloud reflectance is not larger than 2(£5%).