SP00SH00
SP00SH20
SP20SH00
The following table shows the three basic shear cases for large eddy simulations (LES) on a 256x256x80 grid with cubic grid cells (5.12 x 5.12 x 1.6 km). The three cases are: SP00SH00 (surface geostrophic wind SPeed of 0 m/s with SHear of 0 m/s), SP00SH20 (surface wind SPeed of 0 m/s, SHear of the geostrophic wind of 20 m/s over the vertical domain), and SP20SH00 (surface wind SPeed of 20 m/s, SHear of the geostrophic wind of 0 m/s over the vertical domain).
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SP00SH00 |
SP00SH20 |
SP20SH00 |
The following table shows the convective boundary layer depth (zi), vs. time, for the three basic shear cases under different conditions of free atmosphere stratification (above the convective boundary layer). The surface buoyancy flux (expressed in terms of temperature) is allowed to have values of 0.03 K-m/s, 0.1 K-m/s, or 0.3 K-m/s. The vertical derivative of potential temperature has a value of 1 K/km, 3 K/km, or 10 K/km.
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0.03 K-m/s |
0.1 K-m/s |
0.3 K-m/s |
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1 K/km |
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3 K/km |
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10 K/km |
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The following table shows the entrainment flux ratio, C1, which is defined as the negative of the ratio of the heat flux of entrainment at the CBL top to the surface heat flux.
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0.03 K-m/s |
0.1 K-m/s |
0.3 K-m/s |
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1 K/km |
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3 K/km |
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10 K/km |
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The temperature and heat flux profiles shown below were selected at times when
C1 appears significantly different in the graphs above. In general, heat
flux profiles (as expected with second order statistics) vary from time to time
during each simulation, but in general, the runs with shear in the geostrophic
wind showed the lowest values of heat flux in the entrainment zone, which is to
be expected given the large values of C1 that these runs have. I will
probably form a normalized composite heat flux profile that would show how the
differences in heat flux profiles look in a more average sense, but I wanted to
get these graphs up on the page for a quick look. The run with 1 K/m and
0.3 K-m/s ran only marginally long enough to establish an entrainment zone with
a negative heat flux before it was necessary to terminate the run due to the
boundary layer depth becoming close to the sponge layer.
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0.03 K-m/s |
0.1 K-m/s |
0.3 K-m/s |
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1 K/km
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3 K/km
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| 10 K/km |
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Potential temperature profiles are shown in the graphs below.
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0.03 K-m/s |
0.1 K-m/s |
0.3 K-m/s |
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1 K/km
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3 K/km
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10 K/km |
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