Using GISS ModelE in single-column mode (master branch only)

Source code files dedicated to single-column model (SCM) are as follows:

-- SCM_COM.F90: common variables for single-column model simulations
-- SCM.F90: code for reading and processing single-column model input data
-- ATMDYN_SCM{,_EXT}.f: code for replacing large-scale dynamics with forcing terms

It is possible to run ModelE in single-column model mode with several
options for initialization and forcing. Current options handle
atmosphere-only runs, with prescribed surface conditions and
large-scale tendencies specified in the run deck. Set preprocessor
option #define SCM. Include object modules SCM_COM, SCM, ATMDYN_SCM,
and ATMDYN_SCM_EXT prior to CLOUDS_COM. User-supplied input files
may currently include the following:

-- SCM_NML: namelist containing all input variable names and unit conversions (required)
-- SCM_PS: surface pressure (required)
-- SCM_TEMP or SCM_THETA: atmospheric temperature profile (required)
-- SCM_WVMR: water vapor mixing ratio profile (required)
-- SCM_TSKIN: surface skin temperature
-- SCM_SFLUX: surface sensible and latent heat fluxes
-- SCM_WIND: horizontal wind profiles
-- SCM_GEO: horizontal geostrophic wind profiles
-- SCM_W or SCM_OMEGA: large-scale vertical wind or pressure tendency profiles
-- SCM_QRAD: radiative heating rate profiles
-- SCM_LS_V: large-scale heat and moisture vertical flux divergence profiles
-- SCM_LS_H: large-scale heat and moisture horizontal flux divergence profiles
-- SCM_FNUDGE: thermodynamic nudging strength profile

Each netCDF input file must contain UTC "year", "month", "day", and
"hour" variables as integer time series with dimension "nt". If
floating point time series (such as surface pressure) contain only
one time, the value will be fixed for all simulation times. Input
files containing a profile variable must contain a pressure grid as a
floating point variable "lev" in units of hPa or mb with dimension
"lev".  For each profile variable, the pressure grid must be fixed
in time if more than one time is provided, but each variable may
be on its own pressure grid.  Profile variables can be combined in
a single input file if they share the same pressure grid.

Run-time parameters include the following:

-- SCM_lon: location longitude (required)
-- SCM_lat: location latitude (required)
-- SCM_area: nominal grid box area for calculation of extrinsic mass fluxes (required)
-- SCM_sfc: 1=land, 2=ocean
-- SCM_ustar: surface friction velocity
-- SCM_z0m: surface roughness height
-- SCM_alb: surface mid-visible albedo
-- SCM_BeersLaw: Beer's law coefficients for radiative flux divergence
-- SCM_tau: nudging time constant for temperature and moisture profiles

The shell script modelE/exec/extract_scm.sh uses SCM_lat and SCM_lon
to extract ancillary input data for a given SCM run location.
Run-time success reading and processing individual input files is
reported to .PRT within the output run directory. Diagnostics are
obtained using the GCM-native subdaily diagnostics system. Diagnostics
made available using this system are opt-in, with variable names
specified in SUBDD{,1,2,3,etc} strings within the run deck.

Existing run-deck templates include the following:

-- SCM.R: DOE ARM Southern Great Plains case with VARANAL data (www.arm.gov)
-- SCM_BOMEX.R: BOMEX case study described by Siebesma et al. (2003)
-- SCM_DYCOMS-II-RF02.R: DYCOMS case study described by Ackerman et al. (2009)