Parameterization of Convective Boundary Layer Turbulence and Clouds
93
Figure 4.6 presents the temporal evolution of the mean potential temperature in
the LES simulation. A typical structure of a growing CBL can be observed. The
average profi le of potential temperature corresponds to an unstable surface BL,
a region of a quasi-neutral mixed layer in the inner BL and a strong inversion at
the top.
In what concerns the most vigorous updrafts (Figure 4.7), it can be seen in the
surface BL that they present an excess of potential temperature of the order of
0.2 K, relative to the average domain value, then a monotonous decrease in potential
2.0
Ini
2
4
6
8
10
1.5
1.0
Height (km)
0.5
0.0
298
299
θ (K)
300
301
FIGURE 4.6 Temporal evolution of the potential temperature. Hourly average of the vertical profi les of a LES run.
2.0
1.5
1.0
Height (km)
0.5
0.0
300.1
300.2
θ av
θ up
av
1%
3%
5%
300.3
300.4
300.5
300.6
θ (K)
FIGURE 4.7 Vertical profi les of potential temperature: (av) horizontal domain average, 1%,
3%, and 5% average of the grid points with stronger vertical motion correspondent to the percentiles 0.01, 0.03, and 0.05, respectively. Results of the fourth hour of the LES simulation.
© 2010 by Taylor and Francis Group, LLC