Idealized mountain overflow
The warm microphysics was tested with an idealized mountain overflow. A sensitivity
study was performed with respect to mountain height using initial number
concentrations of 100 cm-3
respectively 1000 cm-3
Initialization of atmosphere by idealized initial sounding after Thompson .
Gauss shaped mountain, initial horizontal wind 15 m/s (from the "left").
400 gridpoints in horizontal direction, resolution 2.8 km.
38 vertical layers, model top 16 km, resolution about 50 m near ground
up to 700 m near top.
The resulting precipitation pattern from model runs with three different mountain
heights and the two different initial aersosol particle number is shown to the left.
The higher the mountain, the more rain results. Also, the peak maximum is shifted
upwind. A more polluted atmosphere leads to less rain.
The total liquid water content (including rain) for the mountain height
1000 m is shown below. The left picture shows the result from the cleaner case,
the right picture the result from the more polluted case. In the latter, most of the
water is located in the cloud, while in the former most of the water is located near
the ground as rain water.
 Thompson et al. (2004), Mon. Wea. Rev., 132, 519-542