Figure 3.

Pixel-average cloud optical depth τ_c as a function of vertical cloud LWP for eight satellite overpasses over the study area 50–55°N, 25–30°W, for April 2–8, 1987. Data points with τ_c > 70 are plotted at τ_c = 70 because of insensitivity of retrieval method at high optical depth; these points are evident as horizontal clusters at τ_c = 70. Data points with τ_c ≲ 3 have been excluded to eliminate pixels that could be covered by haze but not clouds. Lines denote cloud optical depth for indicated constant values of effective radius near cloud top, r_e.