WRF ARW User's Guide - MMM - UCAR

MODEL
data and update these fields. In order to use this option, one must have access to timevarying
SST and sea ice fields. Twelve monthly values vegetation fraction and albedo are
available from the geogrid program. Once these fields are processed via WPS, one
may activate the following options before running program real.exe and wrf.exe:
sst_update = 1
auxinput4_inname = “wrflowinp_d” (created by real.exe)
auxinput4_interval = 360, 360, 360,
l. Using Adaptive Time Stepping
Adaptive time stepping is a way to maximize the time step that the model can use while
keeping the model numerically stable. The model time step is adjusted based on the
domain-wide horizontal and vertical stability criterion. The following set of values would
typically work well.
use_adaptive_time_step = .true.
step_to_output_time = .true. (but nested domains may still be writing output at
the desired time. Try to use adjust_output_times = .true. to make up for this.)
target_cfl = 1.2, 1.2, 1.2,
max_step_increase_pct = 5, 51, 51, (a large percentage value for the nest allows
the time step for the nest to have more freedom to adjust)
starting_time_step = use (-1 means 6*DX at start time)
max_time_step : use fixed values for all domains, e.g. 8*DX
min_time_step : use fixed values for all domains, e.g. 4*DX
Also see the description of these options in the list of namelist on page 5-32.
m. Output Time Series
There is an option to output time series from a model run. To active the option, a file
called “tslist” must be present in the WRF run directory. The tslist file contains a
list of locations defined by their latitude and longitude along with a short description and
an abbreviation for each location. A sample file looks something like this:
#-----------------------------------------------#
# 24 characters for name | pfx | LAT | LON |
#-----------------------------------------------#
Cape Hallett hallt -72.330 170.250
McMurdo Station mcm -77.851 166.713
The first three lines in the file are regarded as header information, and are ignored. Given
a tslist file, for each location inside a model domain (either coarse or nested) a file
containing time series variables at each model time step will be written with the name
pfx.d.TS, where pfx is the specified prefix for the location in the tslist file.
WRF-ARW V3: User’s Guide 5-21