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Mesoscale Modeling

Mesoscale Modeling. Geoff DiMego December 3, 2013 geoff.dimego@noaa.gov 301-683-3764. “Where America’s Climate, Weather, Ocean and Space Weather Services Begin”. Topics. RTMA and the new URMA ( U n R estricted M esoscale A nalysis) HiResWindow upgrade North American Mesoscale upgrade.

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Mesoscale Modeling

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  1. Mesoscale Modeling Geoff DiMego December 3, 2013 geoff.dimego@noaa.gov 301-683-3764 “Where America’s Climate, Weather, Ocean and Space Weather Services Begin”

  2. Topics • RTMA and the new URMA (UnRestricted Mesoscale Analysis) • HiResWindow upgrade • North American Mesoscale upgrade

  3. RTMA/URMAUpgrade to V2.2.0Q2FY2014 Manuel Pondeca, Geoff Manikin, Yanqiu Zhu, Ying Lin, Steven Levine, Jeff McQueen, Jim Purser, Dave Parrish, Geoff DiMego Manuel.Pondeca@noaa.gov 301-683-3656

  4. RTMA:GSI-2DVar Surface Analysis on NDFD grids, • Interpolated NCEP Stage-II Precip, and • NESDIS GOES Sounder Effective Cloud Amount • Before the upgrade: six runs • 1) CONUS-5km (v2.0.0) • 2) CONUS-2.5km (v2.1.0) • 3) Alaska-6km (v2.0.0) • 4) Hawaii-2.5km (v2.0.0) • 5) Puerto Rico-2.5km (v2.0.0) • Guam-2.5km (v2.1.0) • GSI-2DVar Parameters: 2-mT, 2m-SPFH, 2m-TD, 10m-Wind, and Psfc Note the two versions

  5. RTMA:GSI-2DVar Surface Analysis on NDFD grids, • Interpolated NCEP Stage-II Precip, and • NESDIS GOES Sounder Effective Cloud Amount • After the upgrade: onlyfive runs • CONUS-5km sampled(v2.2.0) • 1) CONUS-2.5km (v2.2.0) • Alaska-6km sampled(v2.2.0) • 2) Alaska-3km(v2.2.0) • 3) Hawaii-2.5km (v2.2.0) • 4) Puerto Rico-2.5km (v2.2.0) • 5) Guam-2.5km (v2.2.0) • GSI-2DVar Parameters: 2-mT, 2m-SPFH, 2m-TD, 10m-Wind, Psfc, sfc visibility, 10m wind gust Note unified version

  6. WHAT ELSE IS CHANGING Extend CONUS-2.5km domain to provide support for Northwest River Forecast Center (NWRFC) NWRFC NDFD CONUS AQUA + RED Areas:NDFD CONUS domain RED + YELLOW Areas:NWRFC domain produced at NCEP and shipped to WFO Seattle PURPLE:Extended area currently not disseminated

  7. WHAT ELSE IS CHANGING (continued 1) • URMA (UnRestricted Mesoscale Analysis) • Identical to RTMA except with a 6 hr delay • Hence, unrestricted by real-time requirement • Allows use of late arriving observations • Generated for extended 2.5 km CONUS only • Includes remapped Stage IV precipitation every 6 hr (see BACKUP SLIDES)

  8. WHAT ELSE IS CHANGING (continued 2) • URMA & Alaska 3km to be on AWIPS SBN (in DRG) • CONUS 5 km & Alaska 6 km will go away from ftp & NOMADS but will remain on AWIPS SBN (for now) • 2D GSI: improve background error covariance model, bias correct 2m-T, First Guess at Appropriate Time (FGAT), include low-level sat winds, routinely compute cross-validation for CONUS 2.5 km • First Guess: blend HWRF for tropical storm winds, blend RAP & NAMnest for Alaska 3 km • Use diurnal reject lists for mesonet T & Td and direction-dependent accept lists for mesonet winds (see BACKUP SLIDES)

  9. HiResWindowUpgrade to V6.0Q2FY2014 Matt Pyle, Hui-ya Chuang, ZavisaJanjic, Ying Lin, Eric Rogers Jacob Carley, Eric Aligo, Brad Ferrier, Shun Liu, Perry Shafran Matthew.Pyle@noaa.gov 301-683-3687

  10. HiResWindow v6 Overview-1

  11. HiResWindow v6 Overview-2 Domain and Schedule Changes Current v5 Future v6 06Z,18Z 18Z 00Z,12Z 00Z,12Z 06Z + Guam 00Z,12Z + Guam 00Z,12Z 00Z,12Z 00Z,12Z 06Z,18Z 06Z,18Z Current 5 km output grids will be maintained but produced more often New NDFD CONUS-2.5km and Alaska-3km will be pursued Preemption by hurricane runs will almost certainly return. 11

  12. CONUS NMMB Warm Season Retrospective: Precipitation June 1-19, 2013 24 h precip verification over eastern CONUS Equitable Threat Score This is nice, but… Ops HiresW WRF-NMM Para CONUS NMMB 8 …this is H U G E !! Bias 1 bias=1

  13. North American Mesoscale (NAM) Upgrade to V3.1Q3FY2014 Eric Rogers, Tom Black, Hui-ya Chuang, Mike Ek, ZavisaJanjic, Dennis Keyser, Ying Lin, Jeff McQueen, David Parrish, Matt Pyle, Wan-Shu Wu Jacob Carley, Jim Abeles, Eric Aligo, Ed Colon, Brad Ferrier, George Gayno, DusanJovic, Hsin-Mu Lin, Yangrong Ling, Shun Liu, Perry Shafran, CaterinaTassone, Ratko Vasic, Yihua Wu, YanqiuZhu Eric.Rogers@noaa.gov 301-683-3682

  14. NAM V3.1 Upgrade: Analysis/NDAS changes planned for inclusion • Hybrid-variational-ensemble analysis with global EnKF • New satellite channel bias correction scheme (consistent with global upgrade) • Radiosonde level enhancement between reported levels • Diabatic digital filter initialization in NDAS using latent heat from 88D reflectivity (ala RAP) • New observations and/or treatment thereof • GPS bending angle data instead of refractivity • GOES-15 radiances turned on • New VAD winds produced at NCEP after radial wind quality control • Meteosat-10 wind subtypes w/different data thinning • Mesonet wind use list from RTMA rehabilitates individual site winds rejected by provider • Use GFS ozone in CRTM for radiance assimilation • Turn on variational quality control • Upgraded GSI runs faster and uses less memory • Restore updating of NDAS long-term precipitation budget adjustment by using CCPA product in place of defunct CPC 1/8th degree precipitation analysis. 14

  15. NAM V3.1 Upgrade: NMMB forecast model changes currently planned for inclusion-1 • Modified Gravity Wave Drag/Mountain Blocking scheme: • Retuned to be more responsive to subgrid-scale terrain variability, • Achieves improved synoptic performance without degrading 10-m winds • Updated Betts-Miller-Janjic convective parameterization: • Moister convective profiles, • Convection triggers less, • Achieves improved NAM-12 QPF bias and added convective ‘structure’ 15

  16. NAM V3.1 Upgrade: NMMB forecast model changes currently planned for inclusion-2 • Replace legacy GFDL radiation with RRTM • Microphysics changes (see BACKUP SLIDES): • Reduce max number concentration of ice (too high in ops NAM) • Slightly reduce critical threshold for onset of condensation (10098% RH) • Tuned w.r.t. RRTM to address 2-m temperature cold bias esp. over snow • Land-Surface Model changes (see BACKUP SLIDES): • Increase Zo for 5 veg. types reducing 10-m wind bias in eastern CONUS • Tuned w.r.t. RRTM to address 2-m temperature cold bias esp. over snow 16

  17. NAM V3.1 Upgrade: Changes specific to the NAM Nests • All nests [except 6 km Alaska] will run with explicit convection (all precipitation via gridscale microphysics) • Eliminates the light amount / reduced triggering BMJ • Enhances convective structure without unduly high QPF bias • Gridscale microphysics using Ferrier-Aligo (see BACKUP) • Reduced 2nd order diffusion improves vertical structure of severe convective events in cases suggested by SPC • Separate ‘microphysics species’ advection improves structure of composite reflectivity aloft in severe events (e.g. derecho) 17

  18. Ops NAM (solid) vs Pll NAM (dashed) : Day 1 (black), Day 2 (red), Day 3 (blue) RMS Vector Wind Error over CONUS/Alaska Alaska CONUS 1 September – 15 November 2013

  19. Operational 12 km NAM (red) vs Parallel 12 km NAM (blue) : 24-h QPF scores, all forecasts Equitable Threat Bias 1 June – 31 August 2013 1 September – 15 November 2013 Green Line : Bias = 1.0

  20. Overall, Fewer and Smaller Dropouts 5 month time series of 500 mb height RMS/bias error over CONUS at 72-h, 12z cycle; Ops NAM = Blue, Parallel NAM = Red

  21. B A C K U P S L I D E S

  22. Introduce Diurnal (Day vs night by local sun angle) reject lists for moisture and temperature observations: Find poorly or over exposed stations, use only when over/under exposure does not occur or has little effect. Reject less than 1% of available obs. Introduce wind direction-stratified accept lists • Use station for pre-determined wind-directions: Based on production cycle: 11/04/13, 00Z

  23. OriginalStaticBins

  24. OriginalStaticBins

  25. OriginalStaticBins

  26. White: RTMA obs. Yellow: late arriving obs available to URMA.

  27. Combined Station Counts (URMAvsRTMA) URMA using about 37% more stations

  28. Precipitation URMA 6-. 6-hourly multi-sensor precipitation estimates from the 12 ConUS River Forecast Centers (RFCs) are mosaicked into a national product (the NCEP Stage IV) and remapped to the ConUS and Northwest NDFD grids. Sample precip URMA files with WMO headers: http://www.ftp.emc.ncep.noaa.gov/mmb/precip/st4-urma/

  29. URMA PRECIP IS INTERPOLATED NCEP STAGE-IV PRECIP / 6-h ACCUMULATED 6h pcp accum ending 00Z 5 Nov 2013 Requested by WFOs in view of NPVU ….. at 13:35Z 5 Nov at 14:35Z The RFCs generally transmit their 6-hourly analysis files covering the 12Z-12Z 24h period in the several hours after 12Z. Complete ConUS coverage is usually achieved by 18:35Z. As new versions of analysis come in, we continue to re-make the mosaicks hourly, until 23:35Z. at 17:35Z

  30. HiResWindow v6: Decrease in RMS errors at 48 h forecast time for eastern CONUS 63 cycles from Feb and June 2013 OPS NMM PARA NMMB T Z RH V

  31. More intense convective signals, more in line with observations Model and observed 1 km AGL radar, 09Z 27 April 2011 ops WRF-NMM para NMMB obs para NMMB shows stronger, sharper line Diffuse convective signals in ops WRF-NMM an SPC complaint

  32. More intense convective signals, more in line with observations Modeled and observed 1 km AGL radar, 00Z 20 May 2011 ops WRF-ARW para WRF-ARW • para WRF-ARW better w/: • linear convection in eastern KS • capturing isolated nature of cells over KS/NE. obs

  33. Description of NAM’s Ferrier-Aligo Scheme-1 • Promote more supercooled liquid water • New ice nucleation scheme to reduce # conc of small ice crystals, replacing Meyers et al. (1992) with Fletcher (1962) or Cooper (1986). • New, simpler closure for diagnosing small ice crystals and large, precipitating ice particles from ice mixing ratios. • Delayed initial formation of ice until T<-12C (other thresholds also tested). • Improved processes from analyzing vertical slices • Advection of mass-weighted rime factor (~graupel) • Simplified homogeneous freezing of cloud water at T<-40C • Slightly slower fall speeds of rimed ice (graupel).

  34. Description of NAM’s Ferrier-Aligo Scheme-2 • Higher radar reflectivities • Variable maximum # conc of large ice particles, reduced in conditions when ice mixing ratios are very large. • Increased radar backscatter from wet, melting ice, and at T<0C when rain & ice coexist in intense updrafts. • Combined radar return from rain and heavily rimed ice in areas of intense convection where either (a) ice is formed from freezing of rain drops or (b) rain is formed from melting of large ice. • Increased anvil size • Increase NSImax, the maximum number concentration of small ice from 250 m^-3 to 1000 m^-3. • Increase NLImin, the minimum number concentration of large ice from 0.1 m^-3 to 1 m^-3.

  35. To Reduce Sfc Cold Bias Over Snow, the Following Changes Have Been Made to the NAM-NMMB Land-Surface Model and the Surface Layer Model • To increase the flexibility in the stable surface layer, ZTmax1 & ZTmax2 in JSFC are increased from 1.0 to 9.0 • Added the snow cover array (SNOWC, the fraction of the grid covered by snow) that is calculated in the Noah LSM. The maximum fraction is capped at 0.98 (98% coverage) rather than 1.00 (100%) as in the repository code. The SNOWC array is provided as input to the RRTM radiation for the snow cover, where it was calculated following Marshall et al. (1994; =SNOW/[SNOW+70] for SNOW depth in mm). • The fraction of frozen precipitation is partitioned into liquid and frozen contributions for accumulation in the land surface model. The liquid portion goes into the soil, the frozen portion contributes to the snow pack. • Rime factor is passed into the Noah LSM and used to increase the density of the incoming frozen precipitation in order to reduce the depth of snow accumulations in marginal winter conditions with complex precipitation types. Also, the upper limit of snow density is increased from 0.4 g/cm^3 to 0.9 g/cm^3.

  36. Operational 4 km CONUS (red) vs Parallel 4 km CONUS (blue) : 24-h QPF scores, all forecasts Equitable Threat Bias 1 September – 15 November 2013; No 12z runs after 9/25 1 June – 31 August 2013 Green Line : Bias = 1.0

  37. Surface verification update: Cold bias in parallel NAM, more prevalent in cool season; still being addressed; Cumulative 0-84 h 2-m Temperature RMS/Bias error for 12/1/12-2/28/13, 00z cycles RMS RMS Bias Bias Alaska CONUS Ops NAM : Green : Pll NAM : Magenta

  38. Surface verification update: Recent changes tested in experimental parallel show improvement in cold bias; tests ongoing to improve this further, esp. in Alaska ; Shown is cumulative 0-84 h 2-m Temperature RMS/Bias error for 9/20/13-10/28/13, 12z cycles RMS RMS Bias Bias Alaska CONUS Ops NAM : Green ; Control Pll NAM : Magenta; Exp Pll NAM : Blue

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