Arctic mixed-phase cloud properties from AERI lidar observations: algorithm and results from Sheba

A new approach to retrieve microphysical properties from mixed-phase Arctic clouds is presented. This mixed-phase cloud property retrieval algorithm (MIXCRA) retrieves cloud optical depth, ice fraction, and the effective radius of the water and ice particles from ground-based, high-resolution infrared radiance and lidar cloud boundary observations. The theoretical basis for this technique is that the absorption coefficient of ice is greater than that of liquid water from 10 to 13 [micro]m, whereas liquid water is more absorbing than ice from 16 to 25 txm. MIXCRA retrievals are only valid for optically thin ([[tau].sub.visible]