I quite new to WRF and I am working with an idealized simulation (starting from the squall line 2d X example) and I want to produce a very tall cloud up to the tropopause (~ 16 km). I use a tropical temperature and humidity profile, up to 40 km. The main idea is to use WRF as a cloud resolving model to study deep convection
, with a dx of 250 m, 1500 X-horizontal levels, 200 vertical level, a time step dt of 3s.
To do that, I need a very huge warm bubble (with an horizontal radius of about 150 km and a small vertical one of about 2 km, centred at 2 km of altitude) and several minutes of simulation (typically more than 100, to allow for production of low level U-wind convergence and then enough vertical velocity w to permit cluod formation). An ordinary warm bubble with radius of 10-20 km did not work out (cloud top remains at 2/3 km).
1/ Did anyone of you do similar simulations and have experience with that? Do you confirm the need of such WB to create someting like deep convection?
(i.e. to create a cloud that grows up to the tropopause). I know that a wind shear would help, but my aim is to simulate and analyse such a very symmetryc and "clean" case.
2/ After enough time (about 100-150 mins) cloud forms (with a diameter of about 10 km) but it is very little symmetric (at the beginning) and dramatically asymmetryc
after a while (~20-30 mins after cloud formation)
. This seems to be very strange, because I DO NOT use SOUNDING (I use symmetric boundary conditions on y, open conditions on both left and right X boundaries, very large domain, NO U-wind, NO V-wind). What can drive this strong asymmetry?
numerical errors ? Coriolis (but I think Coriolis is turned off by default, isn't it?)
In addition, I have:
rk_ord=3, diff_opt=2, km_opt=3, khdif and kvdif=0 (but I think these two diffusion coefficients are useless when using Smagorinky parametrization, isn,' it?), damp_opt=3, dampcoef=0.05, zdamp=5000, non_hydrostatic=true, pert_coriolis=false, mix_full_fields=true, h_mom_adv_order=5, v_mom_adv_order=3
Thanks a lot in advance !