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The MM5: Structure and Applications

The MM5: Structure and Applications. Jordan Powers Mesoscale and Microscale Meteorology Division NCAR March 30, 2000 I. BACKGROUND II. THE MM5 MODELING SYSTEM III. MODEL APPLICATIONS. I. BACKGROUND. MM5: FIFTH-GENERATION PENNSYLVANIA STATE

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The MM5: Structure and Applications

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  1. The MM5: Structure and Applications Jordan Powers Mesoscale and Microscale Meteorology Division NCAR March 30, 2000 I. BACKGROUND II. THE MM5 MODELING SYSTEM III. MODEL APPLICATIONS

  2. I. BACKGROUND • MM5: FIFTH-GENERATION PENNSYLVANIA STATE UNIVERSITY / NCAR MESOSCALE MODEL 5 • 3D, NONHYDROSTATIC, PRIMITIVE EQUATION MODEL • MM5 SYSTEM Suite of programs designed to (i) prepare (ii) produce (iii) analyze a meteorological simulation • USE a) Research ( historical simulations ) b) Forecasting ( real-time operation )

  3. ORIGINS Regional model for air quality study ( Anthes and Warner 1978: Mon. Wea. Rev., 106, 1045–1078 ) MM4: Early 1980’s–1993 Nonhydrostatic version developed in 1993 ( Dudhia 1993: Mon. Wea. Rev., 121, 1493-1513 ) DEVELOPMENT Version 1: 1993–1996 Version 2: 1996–1999 Version 3: July 1999 New releases every 3–4 months

  4. MESOSCALE MODELS — A PARTIAL LIST Model Developing and / or Implementing Institution Eta, NGM NCEP Community Meso. Model, RFE AES ( Canada ) ECMWF Model ECMWF UKMO Model U.K. Met. Office ALADIN Meteo-France HIRLAM Met Services: Ireland, Sweden, Finland, Denmark, Spain JLASM Japanese Met. Agency CSIRO LAM Australia Lokalmodell Deutsch Wetterdienst ( Germany ) MM5 NCAR / Penn State RAMS Colorado State ARPS Univ. Of Oklahoma COAMPS U.S. Navy / NRL RUC NOAA / Forecast Systems Lab

  5. MM5 COMMUNITY – >580 users on mailing list – 211 user institutions 57 U.S. Universities 36 federal and state agencies 85 (foreign) institutions (30 countries) 33 private companies

  6. II. THE MM5 MODELING SYSTEM • MM5 ATTRIBUTES • NESTED GRID MODEL – Multiple nests allow for high resolution over key areas – Grids movable, grids may overlap – Generally 3:1 coarse:fine grid size and time step ratios ( 2-way nesting ) – 2-way v. 1-way nesting 2-way: Nest receives input from coarser mesh via its boundaries & nest feeds back to coarser mesh 1-way: Nest receives BC’s from boundary files produced by the coarser mesh, but no nest feedback to coarser mesh

  7. Example of an MM5 nesting configuration Domain 1 = coarsest grid, level 1 Domains 2,3 = level 2 Domain 4 = level 3 Domains 2,3 = overlapping grids

  8. VERTICAL COORDINATE: – Terrain-following ( cf. Eta model– step coord ) –  = p – ptop psfc – ptop – ptop = const (e.g., 50 mb, 100mb) –  = 1 ( sfc ) 0 ( top )

  9. MM5 PHYSICS • Multiple options for atmospheric processes • NONHYDROSTATIC PHYSICS • Nonhyd effects important for x  5 km • MOIST PROCESS TREATMENTS • EXPLICIT SCHEMES • a) Grid-scale ( resolved ) precip • b) Operate upon grid point saturation

  10. Available explicit packages – Warm rain • Prognostic eqns. for cloudwater (CLW), rainwater (RNW) – Simple ice: Dudhia • CLW, RNW for T>0C; cloud ice, snow for T<0° C – Mixed-phase: Reisner 1 • Prognostic eqns. for CLW, RNW, ice, snow – Mixed-phase: Reisner 2, Goddard • Prognostic eqns. for CLW, RNW, ice, snow, graupel, ice no. concentration NB: Memory requirements and computational time increase with increasing scheme complexity

  11. CUMULUS PARAMETERIZATIONS a) Subgrid-scale ( parameterized ) precip b) Schemes account for: (i) precip, heating from convection when grid unsaturated (ii) vertical fluxes of heat, moisture, momentum on the unresolved convective scale – Kuo • moisture convergence trigger function ( TF ) • prescribed heating profile – Arakawa-Schubert • large-scale destabilization TF • cloud populations assumed – Fritsch-Chappell • vertical velocity / temp. perturbation TF • single cloud / grid box

  12. CUMULUS PARAMETERIZATIONS – Betts-Miller • designed to represent quasi-equilibrium established by deep convection on large scales in tropics • adjusts to a given post-convective profile – Grell 2 • lifting depth TF • single cloud / grid box • moist downdrafts – Kain-Fritsch • vertical velocity / temp. perturbation TF • cloud-mixing scheme to determine entrainment/detrainment • all available buoyant energy removed in relaxation time

  13. PBL OPTIONS • – Bulk PBL scheme • • coarse vertical resolution in boundary layer • – Blackadar high-resolution scheme • • high vert res in boundary layer • • Bulk Ri dependent PBL regimes • – Burk-Thompson scheme • • coarse or high res in boundary layer • • TKE predicted • – MRF model scheme • • high vert res in boundary layer • • similar to Blackadar, but more efficient computationally • • used in conjunction with 5-layer soil model

  14. PBL OPTIONS • – Gayno-Seaman • • based on Mellor-Yamada TKE prediction • • use of liquid water potential temperature as conserved • variable (for more accurate simulation of PBL in • saturated conditions) • – Eta model scheme • • based on Mellor-Yamada TKE prediction

  15. LAND SURFACE SCHEMES • – Force / restore ( slab / Blackadar ) • • single slab and fixed-temp substrate • • slab temp based on energy budget • – 5-layer soil model • • temp predicted in layers, with fixed substrate below • • vertical temp diffusion eqn. used • – MM5 land surface model ( LSM ) • • uses high-res ( 1-km ) vegetation and soil data • • results show improved reproduction of diurnal variations • in sensible / latent fluxes, skin temp, and soil moisture

  16. Diurnal cycle: Comparison of 2-meter temperature for MM5 with slab surface model, MM5 with Land Surface Model (LSM), and observations from FIFE.

  17. qv (g/kg) MM5-simulated mixing ratio at lowest model level compared to FIFE observations. Slab model, LSM, and obs qv shown.

  18. MM5 OPERATION • STAGES • (1) Preprocessing • Input data preparation • (2) Processing • Compilation and simulation • (3) Postprocessing • Analysis of output • PREPROCESSING • Step MM5 System Program • a) Prepare model terrain ‘Terrain’ • b) Prepare 1st guess field ‘Regrid’ • c) Reanalyze 1st guess w/ obs ‘Little-r’ ( future: 3DVAR ) • d) Interpolate input to -levels ‘Interp’

  19. PROCESSING • a) Compilation • – F77, F90 • b) Execution • – MM5 operable on both shared memory parallel ( SMP ) • & distributed memory parallel ( DMP ) architectures • – High-performance computer / workstation platforms: • SGI, Compaq / DEC, HP, Sun, Cray, Fujitsu, IBM • – MM5 operable on PC’s or laptops

  20. POSTPROCESSING • – Model output visualization and analysis done with • (generally batch mode) graphics software • – Plotting packages • ‘Graph’ ( official MM5 plotting software; • NCAR Graphics req’d ) • ‘RIP’( NCAR Graphics req’d ) • ‘VIS5D’ ( interactive ) • ‘Gempak’

  21. 4) MM5 USER INFORMATION • GENERAL INFORMATION • – http:// www.mmm.ucar.edu / mm5 • MM5 SYSTEM ACQUISITION • ftp ftp.ucar.edu • cd ~mesouser / MM5V3 • DOCUMENTATION • – Sources and info: http:// www.mmm.ucar.edu / mm5 / doc.html • – Main references • “A Description of the Fifth-Generation Penn State / NCAR • Mesoscale Model 5 (MM5)”( Grell et al. 1994 ) • “PSU / NCAR Mesoscale Modelling System Tutorial Class Notes”

  22. MM5 MEETINGS • – Info: http:// www.mmm.ucar.edu / mm5 / whatisnew.html • – Events ( @ NCAR— Boulder, CO ) •  Annual MM5 Users’ Workshop ( June ) •  MM5 Tutorials ( Jan., June )

  23. III. MODEL APPLICATIONS • Coastal dynamics/microphysics — Heavy coastal fog • (Scotland) • 2) Salt breeze — Circulations amid complex terrain • (Great Salt Desert) • 3) Tropical extreme precip — Explicit v. parameterized precip • (Hong Kong) • 4) Typhoon simulation — Forecast track investigation • (Western Pacific) • Real-time forecast • (U.S. / Colorado)

  24. Heavy Coastal Fog: Simulation of the Haar • Attempt to simulate phenomena of heavy North Sea • fog along Scottish coast ( “haar” ) • 30 km / 10 km nested grid configuration • High vertical resolution: 38 half- levels • Sfc — 100 mb • smallest z  12 m • Success in capturing fog and diurnal cycle of • inland penetration

  25. Distribution of the Scottish haar NOAA-8 1448 GMT 27 APRIL 1984 NOAA-7 0836 GMT 27 APRIL 1984 Satellite imagery for 0836 UTC (top) and 1448 UTC (bottom) 27 April 1984

  26. (a) (b) MM5 forecasts of the Scottish haar. Near-surface wind (vectors) and cloudwater (shading) and integrated cloudwater (bold contour) for 0830 UTC (8.5-hr fcst) and (b) 1445 UTC (14.75-hr fcst) 27 April 1984.

  27. High-resolution, real-time forecasts of circulations in complex terrain: The salt breeze • Application: Real-time MM5 systems developed for U.S. Army • for forecasting at Test Ranges • 30 km / 10 km / 3.3 km / 1.1 km nested grid configuration over • Dugway Proving Ground, Utah • Very good short-term fcst of salt breeze through application of • high horizontal resolution

  28. 4-domain configuration of real-time MM5 for simulations over complex terrain of western Utah. ( Real-time forecast cycle timeline shown at bottom )

  29. 10-hour MM5 forecast on Domain 3 (3.3 km) of near-surface winds (vectors) and potential temperature (shaded) valid 2200 UTC 9 September, 1997. Location of 1.1-km grid (Domain 4) shown.

  30. Analysis of surface streamlines from Utah mesonet data over area of 1.1-km grid for 0000 UTC 10 September 1997. Salt breeze boundary extends W–E through middle of region.

  31. 10-hour forecast on 1.1 km grid of near-surface wind (vectors) and potential temperature (shaded) valid 2200 UTC 9 September 1997.

  32. Tropical extreme precipitation: Explicit v.parameterized precip and the moist process“gray area” • Case: Series of MCS’s passing over Hong Kong 8–9 June 1998 • Observed 24-hr rainfall: 408 mm • MM5 simulation with 54 / 18 / 6 km grid configuration • No Cu parameterization on 6-km grid ( fully-explicit moist processes)

  33. Hour 9 (a) (b) Hour 6 • MM5 simulation showing effects of lack of Cu param on fine grid. • Total precip shaded. 18-km grid shown; outline of 6-km nest • appears in left center. (a) Simulation hr 6, valid 18 UTC 8 June 1998. • (b) Simulation hr 9, valid 21 UTC 8 June 1998. • Area seen is southern China coast around Hong Kong.

  34. (b) (a) Hour 6 Hour 9 • MM5 simulation showing effects of lack of Cu param on fine grid • Total explicit precip blue; total parameterized precip red. • 18-km grid shown; outline of 6-km nest appears in left center. • Simulation hr 6, valid 18 UTC 8 June 1998. (b) Simulation hr 9, • valid 21 UTC 8 June 1998. • Area seen is southern China coast around Hong Kong.

  35. Tropical cyclone forecasting: Predictions of typhoon track • • Operational MM5 forecast system ( 135 / 45 / 15 km ) in Taiwan • consistent in tracking Typhoon Sam ( Aug 1999 ) northward • ( instead of WNW ) from genesis region • • TD developed east of northern Philippines 19 Aug 1999 • • Observed track of Sam westward / northwestward track across • South China Sea with landfall in Hong Kong area 22 Aug • • Crash of China Airlines Flt. 642 ( fatalities ) upon landing in • Hong Kong in gale force winds from Sam

  36. Observed (red) and modeled (blue) tracks of Typhoon Sam, Aug 1999. Positions every 12 hours marked. Periods shown are Aug 12 UTC—23 Aug 00 UTC (obsv’d) and 19 Aug 12 UTC— 22 Aug 12 UTC (model).

  37. (a) (b) • Analyzed and 12-hr MM5 forecast SLP for Typhoon Sam, valid 00 UTC • Aug 1999. Contour interval = 1 mb. Window of domain 2 of • 3-domain configuration shown; grid resolution = 45 km. • (a) Analysis. (b) 12-hr forecast.

  38. (a) (b) 12-hr MM5 forecast – analysis wind differences at 00 UTC 20 Aug 1999 for Typhoon Sam showing forcing in South China Sea. Difference vectors shown. Wind speed difference contoured; dashed= negative ( fcst<analyzed ); solid= positive ( fcst>analyzed ); contour interval= 2.5 m/s. Window of domain 2 of 3-domain configuration shown; grid resolution = 45 km. (a) 700 mb. (b) 500 mb.

  39. Real-time NCAR MM5 forecast: Setup • MMM MM5 Site: http:// rain.mmm.ucar.edu / mm5 • Runs • – Main runs ( CONUS ) • – Global run • – Hurricane run ( Aug.–Nov. ) • Configuration (main runs) • – 2 domains: 30 km( CONUS ) • 10 km( Colorado & Rocky Mtn. West ) • – Inits: 0000 UTC & 1200 UTC • – First-guess and boundary conds: Eta model • – Physics: Simple ice, Kain-Fritsch Cu param, MRF PBL scheme

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