EUCLIPSE First Period Report

Figure 10. Inversion jumps of the liquid water potential temperature and the total water
content for ASTEX, the slow, intermediate and fast transitions, and the CGILS S11
stratocumulus column. The coloured squares show the initial jumps. The coloured numbers
sprawling from the ASTEX square indicate the inversion jumps as a function of time (hours
after start up) for five different LES models. For CGILS and the composite cases only the
DALES inversion jump evolutions are shown.
C. CGILS equilibrium state studies
CFMIP and the GCSS WG1 initiated the CGILS project to use idealized large-scale
dynamical conditions to evaluate cloud feedback processes in GCMs. In particular, the
GPCI (GEWEX Pacific Cross Section Intercomparison) cross section (Siebesma et al.
2004) is described by 13 grid boxes starting from (1 o S, 173 o W), with increments of 3
degrees in latitude and 4 degrees in longitude in the north eastward to the California
coast at (35 o N, 125 o W). CGILS considers three grid points (see Figure 11):
(1) S6 — at (17 o N, 149 o W), the middle point of the GPCI cross section, to represent
the shallow cumulus regime;
(2) S11 — at (32 o N, 129 o W), near the California coast, to represent the
stratocumulus regime;
(3) S12 — at (35 o N, 125 o W), immediately off the California coast, to represent the
stratus regime
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