Recent performance statistics for AMPS real-time forecasts Kevin W. Manning – National Center for Atmospheric Research NCAR Earth System Laboratory Mesoscale and Microscale Meteorology Division Boulder, CO – NCAR is sponsored by the National Science Foundation – AMPS is sponsored by the NSF Office of Polar Programs and the NSF UCAR and Lower Atmosphere Facilities Oversight Section – Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Nov 2011, Columbus, OH – 1

AMPS real-time forecasts 6 two-way interactive grids: – 45-km / 15-km grids to 120 forecast hours – 5-km / 1.67-km grids to 36 forecast hours Initial conditions – GFS 0.5-degree analyes used as first guess for WRFDA 3D variational data assimilation step (domains 1 and 2) – Sea-ice conditions from near real-time SSM/I daily global ice concentration (NSIDC) (25-km grid) Domain 1 boundary conditions – GFS 0.5-degree forecast updated at 6-hour intervals WRF options – 44 vertical levels; lowest half level ~ 12 m above surface; 12 layers below ~1 km above surface – Microphysics: WSM 5-class scheme – LW Radiation: RRTMG – SW Radiation: Goddard SW scheme – Surface Layer Physics: Monin-Obukhov (Janjic Eta) scheme – Land Surface: Noah Land-surface model; 4 subsurface layers – PBL Physics: MYJ (Eta) TKE scheme 2 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model

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AMPS statistics – Summertime Surface Nov-Dec-Jan 2010/2011 season – Temperature – Pressure – Wind Surface station reports – From GTS – From University of Wisconsin – Antarctic Meteorological Research Center (AMRC) Three regions – Ross Ice Shelf – East Antarctic plateau – East Antarctic coastal Older WRF version with Polar modifications 4 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model

Summer T – Ross Ice Shelf Mean Statistics -- ~ 15 stations Bias RMSE Correlation (-1.0 to 1.0) 5 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Summer T – East Antarctic Plateau Mean Statistics ~ 6 stations Bias RMSE Correlation (-1.0 to 1.0) 6 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Summer T – East Antarctic Coastal Mean Statistics -- ~10 stations Bias RMSE Correlation (-1.0 to 1.0) 7 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Summer P – Ross Ice Shelf Mean Statistics -- ~ 15 Stations Bias RMSE Correlation (-1.0 to 1.0) 8 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Summer P – East Antarctic Plateau Mean Statistics -- ~ 6 stations Bias RMSE Correlation (-1.0 to 1.0) 9 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Summer P – East Antarctic Coastal Mean Statistics -- ~10 stations Bias RMSE Correlation (-1.0 to 1.0) 10 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Summer Wind Speed – Ross Ice Shelf Mean Statistics -- ~ 15 stations Bias RMSE Correlation (-1.0 to 1.0) 11 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Summer Wind Speed – East Antarctic Plateau Mean Statistics -- ~ 6 stations Bias RMSE Correlation (-1.0 to 1.0) 12 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Summer Wind Speed – East Antarctic Coastal Mean Statistics -- ~10 stations Bias RMSE Correlation (-1.0 to 1.0) 13 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Summertime Summary – Warm bias on plateau. Mixed temperature bias in other regions. – Warming trend in East Antarctic plateau and Ross Ice Shelf regions. Very little temperature trend for coastal stations. – Plateau stations show greatest temperature error growth (RMSE) over 120 hours. Little temperature error growth (RMSE) for Ross Ice Shelf and coastal regions. – Pressure statistics show high correlation in all three regions, but steady error (RMSE) growth. – Low pressure bias increasing in time over Ross Ice Shelf. – Slight high wind-speed bias 14 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model

AMPS Behavior – Wintertime Surface May-Jun-Jul 2011 Newer WRF version with Polar Modifications 15 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model

Winter T -- Ross Ice Shelf region Mean Statistics -- ~21 stations Bias RMSE Correlation (-1.0 to 1.0) 16 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Winter T -- East Antarctic Plateau Mean Statistics – ~13 stations Bias RMSE Correlation (-1.0 to 1.0) 17 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Winter T -- East Antarctic Coastal Mean Statistics -- ~15 stations Bias RMSE Correlation (-1.0 to 1.0) 18 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Winter P -- Ross Ice Shelf region Mean Statistics -- ~21 stations Bias RMSE Correlation (-1.0 to 1.0) 19 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Winter P -- East Antarctic Plateau Mean Statistics -- ~13 stations Bias RMSE Correlation (-1.0 to 1.0) 20 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Winter P -- East Antarctic Coastal Mean Statistics -- ~15 stations Bias RMSE Correlation (-1.0 to 1.0) 21 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Winter Wind Speed -- Ross Ice Shelf region Mean Statistics -- ~21 stations Bias RMSE Correlation (-1.0 to 1.0) 22 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Winter Wind Speed – East Antarctic Plateau Mean Statistics -- ~13 stations Bias RMSE Correlation (-1.0 to 1.0) 23 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Winter Wind Speed -- East Antarctic Coastal Mean Statistics -- ~15 stations Bias RMSE Correlation (-1.0 to 1.0) 24 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model Forecast Hour (0 – 120)

Wintertime summary – In each region, a mix of high and low temperature biases – average bias near zero. – Over plateau, strong signal of initial condition warm bias that the model quickly corrects. – Larger temperature error (RMSE) growth, larger reduction of temperature correlation, than we saw in summer. – As in summer, pressure statistics show significant error growth (RMSE) – High wind speed bias, more notable than in summer. Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model 25

Subsurface Temperature Initialization BPRC Antarctic results differ from AMPS results – BPRC results show cold bias in summer over East Antarctic Plateau – AMPS results show warm bias in summer over East Antarctica Plateau One possibly significant difference in the AMPS and BPRC is the initialization of subsurface temperature fields – AMPS cycles the subsurface temperature from one forecast to the next High resolution details In balance with WRF physics Subject to model drift – BPRC initializes subsurface temperature fields using a 40-year annual mean air temperature analysis at deep ice layers, and a 40-year monthly mean air temperature analysis at the shallowest subsurface layer No spin-up required Low resolution Could this account for the different results for forecasts of air temperature? 26 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model

Two experiments Cycled subsurface temperature fields (CYCLE) Subsurface temperature fields initialized from monthly mean and annual mean temperatures (MEANT) Two 72-hour forecasts per day, in the AMPS 45km/15km configuration, from 10 Jan through 06 Feb 2011 (about 4 weeks). – The CYCLE conditions have been spun up for about 6 weeks, starting from AMPS real-time fields (i.e., already using the real-time cycled conditions) from 01 Dec Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model

MEANT Level 2 (-0.25 m) T CYCLE Level 2 (-0.25 m) Ice T Difference Level 2 T (-0.25 m) CYCLE – MEANT Averages at Forecast hour 00 28

Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model MEANT Level 4 (-1.5 m) Ice T CYCLE Level 4 (-1.5 m) Ice T Difference Level 4 T (-1.5 m) CYCLE – MEANT Averages at Forecast hour 00 29

Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model MEANT 2-m air Temperature CYCLE 2-m air Temperature Difference 2-m air T CYCLE – MEANT Averages at Forecast hour 72 30

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Short-term plans for sea-ice code in WRF, particularly Noah LSM Currently, sea-ice code is scattered throughout the Noah LSM code – Difficult to trace the sea-ice processes through the code – Difficult to develop or replace Plan: Pull sea-ice code out of Noah-LSM, and make the Noah sea-ice treatment its own separate WRF module – Easy to trace the sea-ice processes through the code – Easy to develop or replace A place to link up with more sophisticated sea-ice schemes or models – Easy to use with other LSM options (e.g., the new Noah- MP LSM) 32 Workshop on Polar Simulations with the Weather Research and Forecasting (WRF) Model