Codes Employed

The GMTB SCM code consists of three components packaged into one software repository on NOAA's Virtual Laboratory (VLab). The specific code used for this test can be found within the 'gmtb-scm' project on VLab, in the 'gf_test' branch, under the tag v1.2. Details for the individual components are as follows:

1. SCM Infrastructure
   • v1.2
2. Physics Driver
   • v2+
   • used the version of nuopc_physics.f90 from r85909 of the GSM branch 'gf-test-new'
   • note: the driver does not contain development since October 2016 (v3 or v4)
3. Physics Suites
   • GFS operational suite found in r85909 of the GSM branch 'gf-test-new'
   • Grell-Freitas-modified operational suite found in r85909 of the GSM branch 'gf-test-new'

Physics configuration is identical to the global model tests.

Control Configuration (SAS)

Microphysics:	Zhao-Carr
Radiation (LW/SW):	RRTMG
Gravity Wave Drag:	Orographic and Convective Gravity Wave Drag
PBL:	Hybrid Eddy-diffusivity Mass-flux Scheme
Deep Convection:	Simplified Arakawa-Schubert
Shallow Convection:	Mass-Flux based SAS

Test Configuration (GFTEST)

Microphysics:	Zhao-Carr
Radiation (LW/SW):	RRTMG
Gravity Wave Drag:	Orographic and Convective Gravity Wave Drag
PBL:	Hybrid Eddy-diffusivity Mass-flux Scheme
Deep Convection:	Grell-Freitas
Shallow Convection:	Grell-Freitas

Other settings

• When GF is activated, several additional parameters can be set:
    imid = 0 (mid-level clouds turned off)
    ichoice = 0 (deep convection closure option)
    ichoice_s = 2 (shallow convection closure option)
    dicycle = 1 (diurnal cycle adjustment turned on)

ARM TWP-ICE Case

The SCM was configured to run the GCSS Deep Convective Working Group's sixth intercomparison case based on the ARM Tropical Warm Pool - International Cloud Experiment (TWP-ICE) field campaign. Full case specifications can be found here and a paper describing a SCM intercomparison performed in 2011-2012 was written by Davies et al. (2013). Highlights of the case configuration are as follows.

• initial conditions and forcing obtained from field campaign data near Darwin, Australia during January and February 2006
• featured deep convection associated with active phase of monsoon and suppressed convection associated with inactive phase

Case Setup

Initial Conditions:	mean profiles of u, v, T, q over the study area centered on 12.425°S, 130.891°E at 3 UTC on January 19, 2006
Surface:	oceanic, fixed SST
Forcing:	prescribed horizontal advection of T, q prescirbed vertical velocity applied to modeled T, q profiles for vertical advection horizontal momentum relaxed to observed profiles on 2 h timescale
Runtime:	3 UTC on January 19, 2006 to 21 UTC on February 12, 2006

Forcing Ensemble

In addition to a “best estimate” forcing dataset for the time period, a 100-member forcing ensemble supplied by the case coordinators is utilized to gauge sensitivity to the supplied forcing. The forcing ensemble was created by quantifying uncertainty in the surface rainfall measurement and using the constrained variational analysis method to derive 100 equally likely forcing profiles. The largest change among the forcing datasets is in the prescribed vertical velocity, which is very sensitive to surface precipitation.