:orphan: Microphysics ============ | Physics Contents ---------------- `WRF Physics Overview`_ |br| `Cumulus Parameterization`_ |br| Microphysics_ |br| Radiation_ |br| `Planetary Boundary Layer (PBL) Physics`_ |br| `Surface Physics`_ |br| `Using Physics Suites`_ |br| `Physics Options for Specific Applications`_ .. _`WRF Physics Overview`: physics.html .. _`Cumulus Parameterization`: cumulus.html .. _Microphysics: microphysics.html .. _Radiation: radiation.html .. _`Planetary Boundary Layer (PBL) Physics`: pbl.html .. _`Surface Physics`: surface.html .. _`Using Physics Suites`: phys_suites.html .. _`Physics Options for Specific Applications`: specific_applications.html | Microphysics Overview --------------------- .. image:: images/mp.png :width: 600px :align: center :height: 350px .. image:: images/blank_image.png :width: 800px :height: 25px WRF microphysics schemes are responsible for resolving water vapor, cloud, and precipitation processes, and some schemes account for ice and/or mixed-phases processes. Microphysics schemes provide atmospheric heat and moisture tendencies to the radiation scheme, and the resolved-scale (or NON-convective) rainfall to the surface scheme. WRF microphysics schemes take into account many different microphysical processes, and formation of particles differs, depending on their type. * Cloud droplets (10s of microns) condense from vapor at water saturation. * Rain (~mm diameter) forms from cloud droplet growth. * Ice crystals (10s of microns) form from freezing of droplets or deposition on nuclei, which are assumed or explicit (e.g., dust particles). * Snow (100s of microns) forms from growth of ice crystals at ice supersaturation and their aggregation. * Graupel/hail (mm to cm) form and grow from mixed-phase interactions between water and ice particles. * Precipitating particles are typically assigned to an observationally-based size distribution. There are many types of microphysics schemes available in WRF. Single-moment schemes have a single prediction equation for mass per species, with particle size distribution being derived from fixed parameters (Qr, Qs, etc.). Double-moment schemes add a prediction equation for number concentration per double-moment species (Nr, Ns, etc.), and allow for additional processes, such as size-sorting, during fall-out and aerosol effects. Spectral bin schemes resolve size distribution by doubling mass bins. The more advanced the scheme type, the more computationally expensive the model simulation will be. | .. note:: *For additional details, see the `WRF Tutorial presentation on Microphysics`_.* | .. _`WRF Tutorial presentation on Microphysics`: https://www2.mmm.ucar.edu/wrf/users/tutorial/presentation_pdfs/202101/dudhia_physics_microphysics.pdf Microphysics Options -------------------- | *In the below table, abbreviations are defined as follows* .. image:: images/mp_abbreviations.png :width: 670px :height: 350px | .. csv-table:: :widths: 50, 20, 50, 50 :align: left :header: "Scheme", "Option", "Mass Variables", "Number Variables" "Kessler", 1, "Qc Qr", N/A "Purdue Lin", 2, "Qc Qr Qi Qs Qg", N/A "WSM3", 3, "Qc Qr", N/A "WSM5", 4, "Qc Qr Qi Qs", N/A "Eta (Ferrier)", 5, "Qc Qr Qs Qt*", N/A "WSM6", 6, "Qc Qr Qi Qs Qg", N/A "Goddard 4-ice", 7, "Qc Qr Qi Qs Qg Qh", N/A "Thompson", 8, "Qc Qr Qi Qs Qg", "Ni Nr" "Milbrandt 2-mom", 9, "Qc Qr Qi Qs Qg Qh", "Nc Nr Ni Ns Ng Nh" "Morrison 2-mom", 10, "Qc Qr Qi Qs Qg", "Nr Ni Ns Ng" "CAM 5.1", 11, "Qc Qr Qi Qs", "Nc Nr Ni Ns" "SBU-YLin", 13, "Qc Qr Qi Qs", N/A "WDM5", 14, "Qc Qr Qi Qs", "Nn Nc Nr" "WDM6", 16, "Qc Qr Qi Qs Qg", "Nn Nc Nr" "NSSL 2-mom", 17, "Qc Qr Qi Qs Qg Qh", "Nc Nr Ni Ns Ng Nh" "NSSL 2-mom+CCN", 18, "Qc Qr Qi Qs Qg Qh", "Nc Nr Ni Ns Ng Nh Nn" "NSSL 7-class", 19, "Qc Qr Qi Qs Qg Qh", "Vg" "NSSL 6-class", 21, "Qc Qr Qi Qs Qg", N/A "NSSL 6-class 2-mom", 22, "Qc Qr Qi Qs Qg", "Nn Nc Nr Ni Ns Ng Vg" "WSM7", 24, "Qc Qr Qi Qs Qg Qh", N/A "WDM7", 26, "Qc Qr Qi Qs Qg Qh", "Nc Nr" "Thompson Aerosol", 28, "Qc Qr Qi Qs Qg", "Nc Ni Nr Nn Nni" "HUJI Fast", 30, "Qc Qr Qi Qs Qg", "Nn Nc Nr Ni Ns Ng" "HUJI Full", 32, "Qc Qr Qic Qip Qid Qs Qg Qh", "Nn Nc Nr Nic Nip Nid Ns Ng Nh" "P3", 50, "Qc Qr Qi", "Nr Ni Ri Bi" "P3-nc", 51, "Qc Qr Qi", "Nc Nr Ni Ri Bi" "P3-2nd", 52, "Qc Qr Qi2", "Nc Nr Ni Ni2 Ri Ri2 Bi Bi2" "P3-3mc", 53, "Qc Qr Qi", "Nc Nr Ni Ri Bi Zi" "ISHMAEL", 55, "Qc Qr Qi Qi2 Qi3", "Nr Ni Ni2 Ni3 Vi Vi2 Vi3 Ai Ai2 Ai3" "ISHMAEL", 55, "Qc Qr Qi Qi2 Qi3", "Nr Ni Ni2 Ni3 Vi Vi2 Vi3 Ai Ai2 Ai3" .. _`WRF Physics References`: https://www2.mmm.ucar.edu/wrf/users/physics/phys_references.html#MP | Microphysics Option Details and References ------------------------------------------ **Kessler** |br| *mp_physics=1* |br| A warm-rain (i.e., no ice) scheme used commonly in idealized cloud modeling studies |br| `Kessler, 1969`_ .. _`Kessler, 1969`: https://doi.org/10.1007/978-1-935704-36-2_1 | **Purdue Lin** |br| *mp_physics=2* |br| A sophisticated scheme that has ice, snow, and graupel processes, suitable for real-data high-resolution simulations |br| `Chen and Sun, 2002`_ .. _`Chen and Sun, 2002`: https://doi.org/10.2151/jmsj.80.99 | **WRF Single-moment 3-class (WSM3)** |br| *mp_physics=3* |br| A simple, efficient scheme with ice and snow processes, suitable for mesoscale grid sizes |br| `Hong et al., 2004`_ .. _`Hong et al., 2004`: https://doi.org/10.1175/1520-0493(2004)132%3C0103:ARATIM%3E2.0.CO;2 | **WRF Single-moment 5-class (WSM5)** |br| *mp_physics=4* |br| A slightly more sophisticated version of WSM3 that allows for mixed-phase processes and super-cooled water |br| `Hong et al., 2004`_ .. _`Hong et al., 2004`: https://doi.org/10.1175/1520-0493(2004)132%3C0103:ARATIM%3E2.0.CO;2 | **Ferrier Eta** |br| *mp_physics=5* |br| The operational microphysics used in NCEP models; simple and efficient, with diagnostic mixed-phase processes; for use with fine resolutions (<5km) |br| `NOAA, 2001`_ .. _`NOAA, 2001`: http://www.emc.ncep.noaa.gov/mmb/mmbpll/eta12tpb/ | **WRF Single-moment 6-class (WSM6)** |br| *mp_physics=6* |br| Includes ice, snow and graupel processes, suitable for high-resolution simulations |br| `Hong and Lim, 2006`_ .. _`Hong and Lim, 2006`: https://www.researchgate.net/profile/Song-You-Hong/publication/331192569_Hongandlim-JKMS-2006/links/5c6b581f92851c1c9dea9d10/Hongandlim-JKMS-2006.pdf?_sg%5B0%5D=started_experiment_milestone&origin=journalDetail | **Goddard 4-ice** |br| *mp_physics=7* |br| Predicts hail and graupel separately; provides effective radii for radiation. *Replaced older Goddard scheme in V4.1.* |br| `Tao et al., 1989`_ |br| `Tao et al., 2016`_ .. _`Tao et al., 1989`: https://doi.org/10.1175/1520-0493(1989)117%3C0231:AIWSA%3E2.0.CO;2 .. _`Tao et al., 2016`: https://doi.org/10.1002/2015JD023986 | **Thompson et al.** |br| *mp_physics=8* |br| Includes ice, snow and graupel processes suitable for high-resolution simulations |br| `Thompson et al., 2008`_ .. _`Thompson et al., 2008`: https://doi.org/10.1175/2008MWR2387.1 | **Milbrandt-Yau Double-moment 7-class** |br| *mp_physics=9* |br| Includes separate categories for hail and graupel with double-moment cloud, rain, ice, snow, graupel and hail |br| `Milbrandt and Yau, 2005 (Part I)`_ |br| `Milbrandt and Yau, 2005 (Part II)`_ .. _`Milbrandt and Yau, 2005 (Part I)`: https://doi.org/10.1175/JAS3534.1 .. _`Milbrandt and Yau, 2005 (Part II)`: https://doi.org/10.1175/JAS3535.1 | **Morrison Double-moment** |br| *mp_physics=10* |br| Double-moment ice, snow, rain and graupel for cloud-resolving simulations |br| `Morrison et al., 2009`_ .. _`Morrison et al., 2009`: https://doi.org/10.1175/2008MWR2556.1 | **CAM V5.1 2-moment 5-class** |br| *mp_physics=11* |br| `User's Guide to the CAM-5.1`_ .. _`User's Guide to the CAM-5.1`: https://www.cesm.ucar.edu/models/cesm1.0/cam/docs/ug5_1/ug.html | **Stony Brook University (Y. Lin)** |br| *mp_physics=13* |br| A 5-class scheme with riming intensity predicted to account for mixed-phase processes |br| `Lin and Colle, 2011`_ .. _`Lin and Colle, 2011`: https://doi.org/10.1175/2010MWR3293.1 | **WRF Double-moment 5-class (WDM5)** |br| *mp_physics=14* |br| Similar to WSM5 (option 4), but includes double-moment rain, and cloud and CCN for warm processes |br| `Lim and Hong, 2010`_ .. _`Lim and Hong, 2010`: https://doi.org/10.1175/2009MWR2968.1 | **WRF Double-moment 6-class (WDM6)** |br| *mp_physics=16* |br| Similar to WSM6 (option 6), but includes double-moment rain, and cloud and CCN for warm processes |br| `Lim and Hong, 2010`_ .. _`Lim and Hong, 2010`: https://doi.org/10.1175/2009MWR2968.1 | **Note** |br| *For NSSL single-moment schemes (options 19 and 21), intercept and particle densities can be set for snow, graupel, hail, and rain. For the single- and double-moment schemes (options 17,18, 19, 21, and 22), shape parameters for graupel and hail can be set (in te &physics section of namelist.input).* * **nssl_alphah=0.** : shape parameter for graupel * **nssl_alphahl=2.** : shape parameter for hail * **nssl_cnoh=.e5** : graupel intercept * **nssl_cnohl=4.e4** : hail intercept * **nssl_cnor=8.e5** : rain intercept * **nssl_cnos=3.e6** : snow intercept * **nssl_rho_qh=500.** : graupel density * **nssl_rho_qhl=900.** : hail density * **nssl_rho_qs=100.** : snow density | **NSSL Double-moment** |br| *mp_physics=17* |br| Two-moment scheme for cloud droplets, rain drops, ice crystals, snow, graupel, and hail; also predicts average graupel particle density, which allows graupel to span the range from frozen drops to low-density graupel |br| `Mansell et al., 2010`_ .. _`Mansell et al., 2010`: https://doi.org/10.1175/2009JAS2965.1 | **NSSL Double-moment with CCN prediction** |br| *mp_physics=18* |br| Similar to option 17 (above), but also predicts cloud condensation nuclei (CCN) concentration (intended for idealized simulations); intended for cloud-resolving simulations (dx <= 2km) in research applications |br| `Mansell et al., 2010`_ * To set global CCN value, use "nssl_cccn=0.7e9," which also sets the same value for "ccn_conc" .. _`Mansell et al., 2010`: https://doi.org/10.1175/2009JAS2965.1 | **NSSL Single-moment 7-class** |br| *mp_physics=19* |br| A single-moment version of option 17 (above) |br| *No publication available* | **NSSL single-moment 6-class** |br| *mp_physics=21* |br| Intended for cloud-resolving simulations (dx <= 2km) in research applications; similar to |br| `Gilmore et al. (2004)`_ .. _`Gilmore et al. (2004)` : https://doi.org/10.1175/MWR2810.1 | **NSSL Double-moment with Graupel** |br| *mp_physics=22* |br| Similar to option 17 (above), without hail |br| *No publication available* | **WRF Single-moment 7-class (WSM7)** |br| *mp_physics=24* |br| Similar to WSM6 (option 6), but with an added hail category *(effective beginning with V4.1)* |br| `Bae et al., 2018`_ .. _`Bae et al., 2018`: https://doi.org/10.1007%2Fs13143-018-0066-3 | **WRF Double-moment 7-class (WDM7)** |br| *mp_physics=26* |br| Similar to WDM6 (option 16), but with an added hail category *(effective beginning with V4.1)* |br| `Bae et al., 2018`_ .. _`Bae et al., 2018`: https://doi.org/10.1007%2Fs13143-018-0066-3 | **Thompson Aerosol-aware** |br| *mp_physics=28* |br| Considers water- and ice-friendly aerosols |br| `Thompson and Eidhammer, 2014`_ * A climatology dataset may be used to specify initial and boundary conditions for the aerosol variables; includes a surface dust scheme. * Since V4.4 a `black carbon aerosol category`_ is added; biomass burning can also be added. .. _`Thompson and Eidhammer, 2014`: https://doi.org/10.1175/JAS-D-13-0305.1 .. _`black carbon aerosol category`: https://www2.mmm.ucar.edu/wrf/users/physics/mp28_updated_new.html | **Hebrew University of Jerusalem Fast (HUJI)** |br| *mp_physics=30* |br| Spectral bin microphysics, fast version |br| `Khain et al., 2010`_ .. _`Khain et al., 2010`: https://doi.org/10.1175/2009JAS3210.1 | **Hebrew University of Jerusalem Full (HUJI)** |br| *mp_physics=32* |br| Spectral bin microphysics, full version |br| `Khain et al., 2004`_ .. _`Khain et al., 2004`: https://doi.org/10.1175/JAS-3350.1 | **Morrison double-moment scheme with CESM aerosol** |br| *mp_physics=40* |br| Similar to option 10, but with CESM aerosol added. *This option must be used with the MSKF cumulus scheme (option 11)* |br| *No publication available for this specific scheme* | **Morrison and Milbrandt Predicted Particle Property (P3)** |br| *mp_physics=50* |br| A single ice category that represents a combination of ice, snow and graupel, and also carries prognostic arrays for rimed ice mass and rimed ice volume; single-moment rain and ice. |br| `Morrison and Milbrandt, 2015`_ .. _`Morrison and Milbrandt, 2015`: https://doi.org/10.1175/JAS-D-14-0065.1 | **Morrison and Milbrandt Predicted Particle Property (P3-nc)** |br| *mp_physics=51* |br| As in 50, but adds supersaturation dependent activation and double-moment cloud water |br| `Morrison and Milbrandt, 2015`_ .. _`Morrison and Milbrandt, 2015`: https://doi.org/10.1175/JAS-D-14-0065.1 | **Morrison and Milbrandt Predicted Particle Property (P3-2ice)** |br| *mp_physics=52* |br| As in option 50, but with two arrays for ice and double-moment cloud water |br| `Morrison and Milbrandt, 2015`_ .. _`Morrison and Milbrandt, 2015`: https://doi.org/10.1175/JAS-D-14-0065.1 | **Morrison and Milbrandt Predicted Particle Property (P3-3moment)** |br| *mp_physics=53* |br| As in option 50, but with 3-moment ice, plus double-moment cloud water |br| *No publication available for this specific scheme* | **Jensen ISHMAEL** |br| *mp_physics=55* |br| Predicts particle shapes and habits in ice crystal growth; *(new in V4.1)* |br| `Jensen et al., 2017`_ .. _`Jensen et al., 2017`: https://doi.org/10.1175/JAS-D-16-0350.1 | **National Taiwan University (NTU)** |br| *mp_physics=56* |br| double-moments for the liquid phase, and triple-moments for the ice phase, together with consideration for ice crystal shape and density variations; supersaturation is resolved so that condensation nuclei (CN) activation is explicitly calculated; CN’s mass in droplets is tracked to account for aerosol recycling. |br| `Tsai and Chen, 2020`_ .. _`Tsai and Chen, 2020`: https://doi.org/10.1175/JAS-D-19-0125.1 | .. image:: images/blank_image.png :width: 800px :height: 200px Next section: Radiation_ | | | | .. _Radiation: radiation.html