Foreword
This User’s Guide describes the Advanced Research WRF (ARW) Version 4.0 modeling system, released in June 2018. As the WRF/ARW is developed further, this document will be continuously enhanced and updated. Please post feedback to the WRF & MPAS-A Support Forum.
This document is complementary to the ARW Tech Note (https://opensky.ucar.edu/islandora/object/opensky:2898), which describes the equations, numerics, boundary conditions, and nesting etc. in greater detail.
Highlights of updates to WRFV4.0 include:
· WRF model:
Dynamics and solver:
o Hybrid sigma-pressure vertical coordinate introduced in V3.9 is now default.
o The prognostic variable for temperature is moist potential temperature by default.
Physics:
o P3 microphysics with two free categories (contributed by Morrison and Milbrandt);
o A surface dust emission scheme is added to Thompson-Eidhammer mircrophysics (Thompson, M. Xu and T. Eidhammer of NCAR);
o CESM aerosol is added to Multiscale Kain-Fritsch scheme with Song-Zhang microphysics, and Morrison scheme (Timothy Glotfelty, Patrick Hawbecker, and Kiran Alapaty of EPA);
o Genotype-by-Environment interaction on CROp growth Simulator crop model is added to NoahMP (J. Ingwersen of U. Hohenheim and M. Barlage of NCAR);
o Option to use soil composition data in NoahMP (M. Barlage of NCAR);
o A scale-aware SAS scheme and RRTMG-K (Korea Instituted of Atmospheric Prediction Systems);
o Updated WRF-fire code (Domingo Munoz-Esparza of NCAR)
o Updates to RAP/HRRR and other physics.
· WPS:
o Re-organization of input static data;
o 0.05 degree MODIS albedo and snow albedo (Barlage of NCAR)
· WRF-DA updates:
o GOES-Imager radiance DA (C. Yang of Nanjing University of Information Science & Technology, China and Z. Liu of NCAR)
o GPSRO excess phase observation operator (S.Y. Chen of National Central Univ, S.-H. Chen of UC Davis, S. Sololovskiy of COSMIC and J. Bresch of NCAR)
o Large-scale analysis constrain and divergence constrain (X.W. Tang of Nanjing University, China)
o Integration of WRFPlus code in WRF (subdirectory wrftladj/).
· WRF-Chemistry
o Potential vorticity based stratospheric ozone calculation (S. McKeen, NOAA)
o An updated version of the Model for Simulating Aerosol Interactions and Chemistry scheme (MOSAIC II) (J. Fast of PNNL);
o An updated heterogeneous gas chemistry option coupled to the ISORROPIA II aerosol thermodynamic model (Q. Yi of Hong Kong Polytechnic);
o An integrated reaction rate diagnostics option (S. Walters et al., NCAR);
o Diagnostics for WRF-Chem aerosol-radiation feedback in the radiation driver (D. Lowe, S. Archer-Nicholls, Cambridge University, UK)
o Henry's Law Constant table to use the same constants across different chemistry parameterizations, e.g. dry/wet deposition schemes (M.Barth et al., NCAR).
For the latest version of this document, please visit the ARW Users’ Web site at http://www2.mmm.ucar.edu/wrf/users/.
Contributors to this guide:
Wei Wang, Cindy Bruyère, Michael Duda, Jimy Dudhia, Dave Gill, Michael Kavulich, Kelly Werner, Ming Chen, Hui-Chuan Lin, John Michalakes, Syed Rizvi, Xin Zhang, Judith Berner, Domingo Munoz-Esparza, Brian Reen, Soyoung Ha and Kate Fossell
Contributors to WRF-Fire chapter:
Jonathan D. Beezley, Janice L. Coen, and Jan Mandel
Special Acknowledgment:
We gratefully acknowledge the late Dr. Thomas T. Warner for his years of research, development, instruction, leadership, and motivation in the field of NWP modeling.