Introduction

Author

Global Model Test Bed (GMTB) at NCAR and NOAA/GSD

Welcome to the GMTB Common Community Physics Package (CCPP) V2.0 scientific documentation. This version contains all parameterizations of the 2017 Operational GFS physics suite. In this website you will find documentation on various aspects of the parameterizations, including basic description, input/output argument list and general/detailed algorithm.

A major upgrade to the parameterization of GFDL Cloud Microphysics Scheme was implemented in the fv3gfs, which is slate to be operational at NCEP in 2019. It is the most significant change to the GFS physics suite since the Zhao-Carr microphysics scheme was implemented in the NCEP Global Forecasting System(GFS) as a simple scheme and predicted only total cloud condensate. Six prognostic cloud spieces variables have been introduced to enable a more physically based representation of water vapor, mixed-phase (liquid/ice) cloud and precipitating rain/snow/graupel. A fast physics (phase change only, for now) has been implemented between "Lagrangian-to-Eulerian" remapping in the FV3 dynamic solver.

Other physics Upgrade of Q3FY17 GFS include:

• Use of higher resolution land surface climatologies and new surface albedo data.
  • IGBP 20-type land classifications and STASGO 19-type soil classifications
  • New MODIS-based snow free albedo
  • New MODIS-based maximum snow albedo
  • Updated diurnal albedo treatment
  • Unified snow cover and snow albedo between radiation and Noah LSM
  • Fixed excessive cooling of T2m during sunset

  • Increased ground heat flux under deep snow

    Major issue addressed:

  • Reduced patchiness of land cover and its properties
  • Reduced cold temperature bias over snow: Alaska, Northwest, Northeast
  • Mitigated stable boundary layer decoupling
  • Improved surface exchange coefficient
  • Removed excessive large snow albedo
• Updated land parameterization to reduced excessive cooling of 2m temperatures during sunset (00Z).
• Changes to cumulus convection parameterization to improve summertime precipitation forecasts.
• Included a Near-Surface Sea Temperature model to represent diurnal warming and sub-layer cooling effects.
• Reduced Rayleigh damping in the upper stratosphere to improve temperature and circulation forecast.

Documentation for the individual physics scheme can be accessed through the following links:

• GFS RRTMG Shortwave/Longwave Radiation Scheme
• GFS Surface Layer Scheme
• GFS Near-Surface Sea Temperature Scheme
• GFS Noah Land Surface Model
• GFS Sea Ice Scheme
• GFS Hybrid Eddy-Diffusivity Mass-Flux PBL and Free Atmospheric Turbulence Scheme
• GFS Orographic Gravity Wave Drag Scheme
• GFS Rayleigh Damping Calculation
• GFS Ozone Photochemistry Scheme
• GFS Scale-Aware Mass-Flux Deep Convection Scheme
• GFS Convective Gravity Wave Drag Scheme
• GFS Scale-Aware Mass-Flux Shallow Convection Scheme
• GFDL Cloud Microphysics Scheme

You can find more information about the GMTB Common Community Physics Package (CCPP) on the DTC website.