AMPS Update – June 2014

AMPS Update – June 2014 9th Antarc*c Meteorological Observa*ons, Modeling, and Forecas*ng Workshop 09‐11 June 2014 – Charleston, SC Kevin W. Manning Jordan G. Powers Mesoscale and Microscale Meteorology Division NCAR Earth System Laboratory NaKonal Center for Atmospheric Research Boulder, CO NCAR is sponsored by the NaKonal Science FoundaKon The AntarcKc Mesoscale PredicKon System •  Provides customized NWP support for AntarcKc forecasters –  Forecast model is the Weather Research and ForecasKng Model (WRF‐ARW), tuned for the AntarcKc environment •  Funded by the NaKonal Science FoundaKon –  CollaboraKon between NaKonal Center for Atmospheric Research/
Mesoscale and Microscale Meteorology Division and Ohio State University/Byrd Polar Research Center –  Primary goals are to support USAP forecasters and acKviKes, and to support research and educaKon eﬀorts in AntarcKc meteorology •  Real‐Kme forecasts running since October 2000, through many updates •  Real‐Kme products disseminated primarily through the AMPS web page (www.mmm.ucar.edu/rt/amps/) and the AntarcKc‐IDD network 2 30‐km 3.3‐km 10‐km 1.1‐km 3.3‐km 3 AddiKonal Grids WAISD and PIG grids run as one‐way nests driven by output from the AMPS 10‐km ConKnental grid. New Zealand and Palmer grids run as two‐
way nests of an independent 27‐km grid similar in coverage to the AMPS 30‐km grid. 8‐km 3.3‐km New Zealand WAIS Divide 3.3‐km Pine Island Glacier 9‐km “Palmer” Drake Passage 4 h]p://www.mmm.ucar.edu/rt/amps h]p://amps‐backup.ucar.edu 5 New in the past year •  Layer average winds over Pole 0 – 3000 ` 0 – 5000 ` 6 Tests •  WRF version 3.5.1 w/polar adaptaKons –  currently running 3.3.1 w/polar adaptaKons •  RRTMG Shortwave parameterizaKon –  currently running Goddard SW •  Thompson Microphysics parameterizaKon –  Currently running WSM5 –  PotenKal eﬀect on cloud deﬁcit? •  Temperature/Warming issues –  Increase snow albedo –  Use GFS subsurface temperatures •  Ensemble forecasts 7 Ensemble Forecasts •  See Powers talk 8 WRF version 3.5.1 tests •  ExecuKve summary: No compelling reason to upgrade from version 3.3.1 at this Kme –  By most measures, 3.5.1 veriﬁes slightly worse than 3.3.1 –  Temperature diurnal cycle diﬀerences 9 WRF‐3.3.1 vs. WRF‐3.5.1 Ross Ice Shelf error staKsKcs Jan 2013 Wind speed error staKsKcs Temperature error staKsKcs K m s‐1 K m s‐1 Forecast Hour Forecast Hour 10 WRF‐3.3.1 vs. WRF‐3.5.1 East AntarcKc Plateau error staKsKcs Jan 2013 Wind speed error staKsKcs Temperature error staKsKcs K m s‐1 K m s‐1 Forecast Hour Forecast Hour 11 RRTMG SW tests •  ExecuKve Summary: No compelling reason to switch to RRTMG SW (from Goddard SW) •  Surface temperature scores a li]le worse •  Surface wind speed scores are similar, possibly slightly be]er 12 WRF‐3.3.1 vs. WRF‐3.5.1 vs. WRF‐3.5.1‐RRTMG Ross Ice Shelf error staKsKcs Jan 2013 Wind speed error staKsKcs Temperature error staKsKcs K m s‐1 K m s‐1 Forecast Hour Forecast Hour 13 WRF‐3.3.1 vs. WRF‐3.5.1 vs. WRF‐3.5.1‐RRTMG East AntarcKc Plateau error staKsKcs Jan 2013 Wind speed error staKsKcs Temperature error staKsKcs K m s‐1 K m s‐1 Forecast Hour Forecast Hour 14 Thompson Microphysics •  What does Thompson oﬀer? –  Two‐moment scheme: •  Thompson predicts number concentraKons as well as mixing raKos, allowing for be]er representaKon of parKcle size distribuKons –  Under acKve development –  More computaKonally intensive •  Exploratory tesKng in AMPS –  SuggesKon of more cloud in some areas –  Seems to reduce cloud ice, increase low‐level cloud water, increase snow as a microphysical species •  Several other microphysics schemes in WRF may merit tesKng 15 WRF‐3.3.1 vs. WRF‐3.5.1 vs. WRF‐3.5.1‐Thompson Ross Ice Shelf error staKsKcs Jan 2013 Wind speed error staKsKcs Temperature error staKsKcs K m s‐1 K m s‐1 Forecast Hour Forecast Hour 16 WRF‐3.3.1 vs. WRF‐3.5.1 vs. WRF‐3.5.1‐Thompson East AntarcKc Plateau error staKsKcs Jan 2013 Wind speed error staKsKcs Temperature error staKsKcs K m s‐1 K m s‐1 Forecast Hour Forecast Hour 17 Mean microphysical proﬁles Jan 2013 Oceanic Ross Ice Shelf Plateau > 3000m Signiﬁcantly more low‐level Cloud Water in Thompson Solid Lines: Thompson Microphysics Dashed Lines: WSM6 Microphysics Cloud Ice: Cloud Water: Snow: Rain: Graupel: “Cloud Ice” in WSM5 becomes “Snow” in Thompson 18 Warming issues •  Exploratory tesKng –  Eﬀect of subsurface temperature iniKalizaKon –  Eﬀect of changes to snow albedo 19 Surface temperature error staKsKcs as a funcKon of forecast hour East AntarcKc plateau staKons; Jan 2014 AMPS conﬁguraKon: Snow albedo = 80% Subsurface temperatures cycled 20 AMPS conﬁguraKon: Snow albedo = 80% Subsurface temperatures cycled GFS subsurface temperatures 21 AMPS conﬁguraKon: Snow albedo = 80% Subsurface temperatures cycled GFS subsurface temperatures Snow albedo = 83 % 22 Mean subsurface T forecast as a funcKon of forecast hour over East AntarcKc Plateau (topography > 3000 m) for Jan 2014 IniKalized by cycling subsurface T from previous forecast IniKalized with GFS subsurface T Albedo = 83 % 2‐m Air Temperature Skin Temperature Layer 2: 0.0‐0.1 m Layer 2: 0.1‐0.4 m Layer 3: 0.4‐1.0 m Layer 4: 1.0‐2.0 m 23 Where To Next? •  Ferret out source of the diurnal signal of model error in newer WRF versions •  Further explore growth of temperature bias •  Pursue ensemble forecasts •  Data assimilaKon methods: –  Cycling oﬀ of AMPS forecasts? –  Ensemble DA? 24 

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