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WRF Namelist Configuration

To activate the high-performance boundary layer and surface layer schemes of Shardian Atmos, you must configure the physical options in the WRF control file namelist.input.

1. Configuring the &physics Section

Edit the &physics section of your namelist.input file as follows:

 &physics
  mp_physics                          = 8,      # Thompson microphysics (or any other)
  ra_lw_physics                       = 4,      # RRTMG Longwave
  ra_sw_physics                       = 4,      # RRTMG Shortwave
  radt                                = 9,

  # ACTIVATION OF SHARDIAN ATMOS (EML-SR)
  bl_pbl_physics                      = 99,     # Activates EML-SR Planetary Boundary Layer (pbl)
  sf_sfclay_physics                   = 1,      # Monin-Obukhov Similarity Theory (MOST)
  sf_surface_physics                  = 2,      # Unified Noah Land Surface Model

  bldt                                = 0,
  cudt                                = 5,
  isfflx                              = 1,
  ifsnow                              = 1,
  icloud                              = 1,
  sf_urban_physics                    = 0,
  /

Key Parameters Explained:

  • bl_pbl_physics = 99: Instructs WRF to route vertical turbulent boundary-layer updates through the proprietary module_bl_eml_sr.F solver from Shardian Atmos.
  • sf_sfclay_physics = 1: Selects the Monin-Obukhov Similarity Theory (MOST) surface layer scheme. The Shardian solver couples dynamically with MOST to regulate resistance and vertical heat/momentum fluxes.
  • sf_surface_physics = 2: The Unified Noah Land Surface Model is highly recommended for thermal soil-atmosphere coupling, as Shardian Atmos directly adjusts the calculation of thermal roughness length (\(z_{0h}\)) and boundary-layer aerodynamic resistance.

2. Scientific Foundations of Shardian Atmos (EML-SR)

The scientific core of Shardian Atmos revolves around improving heat and momentum fluxes under extreme stability conditions and complex land use types.

Thermodynamic Resistance (\(kB^{-1}\))

The excess thermodynamic resistance for heat transfer is calculated as:

\[kB^{-1} = \ln\left(\frac{z_{0m}}{z_{0h}}\right)\]

While classical MOST (Dyer-Businger formulations) assumes a constant or linear relation for \(kB^{-1}\), Shardian Atmos employs a non-linear symbolic equation coupled to the sublayer roughness Reynolds number (\(\text{Re}_*\)) and the green vegetation fraction (\(\text{VEGFRA}\)):

\[kB^{-1} = \frac{f(\text{Re}_*, \text{VEGFRA})}{\text{Denominador}_\text{eml}}\]

This symbolic formulation mitigates the day-time "continental warm bias" over dry soils and prevents nocturnal over-cooling.

3. Performance Metrics (RMSE)

In global validation studies against real data from the FLUXNET network in complex out-of-distribution (OOD) meteorological regions, Shardian Atmos (EML-SR) shows a major reduction in thermodynamic coupling error (\(\theta_*\)) relative to standard schemes.

Mean Root Square Error (RMSE) for Thermal Coupling (\(\theta_*\) - K):

Climate / Region Samples MOST (YSU) Beljaars (MYNN) Cheng-B. (MYNN-rev) Webb-J. (MYJ) ACM2 (Pleim) EML-SR (Shardian) Performance Gain vs. MOST
BOMEX (Marine) 100 0.00433 0.00433 0.00433 0.00433 0.00381 0.00298 K +31.13%
BUBBLE (Urban) 57 0.23508 0.23508 0.23508 0.23508 0.23778 0.14912 K +36.57%
COASTAL (Marine) 67 0.17421 0.17421 0.17421 0.17421 0.17645 0.02191 K +87.42%
GABLS1 (Polar) 90 0.05968 0.05998 0.05728 0.05984 0.05295 0.02906 K +51.31%
WANGARA (Arid) 100 0.71228 0.71228 0.71228 0.71228 0.64997 0.37486 K +47.37%

Validation Highlights: - In marine and coastal boundaries (COASTAL), Shardian Atmos decreases thermodynamic coupling error by 87.42% through precise water-surface flux damping. - Under highly stable nocturnal boundaries (GABLS1) and continental arid zones (WANGARA), the error is halved (+47% to +51%), preventing the nocturnal decoupling issue.