Distributions of liquid, vapor, and ice in an orographic cloud from field observations

The vapor values are calculated from thermodynamic measurements, and the liquid is measured directly with a Johnson-Williams hot-wire device. Ice mass is calculated from particle size spectra obtained with a two-dimensional optical array cloud probe. Maximum vapor mass in the cloud is 2.0g m^-3, which is comparable with maximum ice mass in the cloud of 1.5g m^-3. Maximum liquid mass is approximately one order of magnitude lower at 0.15g m^-3 and appears to be a small remainder between the vapor and the ice as they compete for the major portion of the cloud water mass. In the cloud upwind of the mountain, liquid + vapor + ice is nearly constant, suggesting that precipitation does not deplete the water mass at the levels studied by the aircraft. Maxima in both ice and liquid mass appear just over the windward crest of the mountain, indicating a strong orographic effect on condensation of vapor to liquid growth of ice by vapor diffusion and riming. The distribution of crystal habits also suggests a significant downdraft exists just downwind of the mountain. -from Authors