Land-Surface Modeling Performance At NCEP NCEP: Where America's Climate and Weather Services Begin WRF Land Working Group Workshop: 18 June 03 Ken Mitchell NCEP Environmental Modeling Center

Collaborators GAPP GCIP Eric Wood Justin Sheffield Princeton Univ. Dan Tarpley NOAA/NESDIS Bruce Ramsay Andy Bailey Soroosh Sorooshian James Shuttleworth Luis Bastidas Univ. Arizona Dennis Lettenmaier Laura Bowling Univ. Washington George Gayno AFWA Jerry Wegiel Wayne Higgins Huug Van den Dool NCEP/CPC Ken Mitchell Michael Ek Dag Lohmann NCEP/EMC Rachel Pinker Hugo Berbery Univ. Maryland Ken Crawford Jeff Basara Univ. Oklahoma Alan Robock Lifeng Luo Rutgers Univ. John Schaake Victor Koren Qingyun Duan NWS/OHD Tilden Meyers Jon Pliem NOAA/ARL Atmospheric Research Alan Betts Paul Houser Brian Cosgrove NASA/GSFC Fei Chen Jimy Dudhia NCAR Mike Fennessey Paul Dirmeyer COLA

Papers recently submitted to GCIP Special Issue of JGR (Show vugraphs and pass out CDs) Papers on Coupled Eta/Noah and EDAS –Ek et al. –Berbery et al. Papers on Uncoupled NLDAS –NLDAS: N. American Land Data Assimilation System –Mitchell et al. overview paper –9 companion papers by NLDAS collaborators

Systems Using the Noah Land Model OPERATIONAL SYSTEMS 1.Eta/EDAS: NCEP Eta Model and Eta Data Assimilation System 2.GFS/GDAS: NCEP Global Forecast System (older version of Noah) 3.AGRMET: Air Force Agricultural Meteorological Model (USDA) DEMONSTRATION TESTBED SYSTEMS 1.Eta-RCM: Eta Regional Climate Model, 2-4 month seasonal fore 2.Eta R/R: Eta-based Regional Reanalysis (underway, ) 3.GFS: NCEP Global Model (most current Noah version) 4.NLDAS Realtime: N. American Land Data Assimilation System 5.NLDAS Retrospective: 50-year by CPC (for drought monitoring) 6.GLDAS: NASA/NCEP Global Land Data Assimilation System 7.MM5/Noah: at NCAR 8.WRF/Noah: at NCAR and NCEP 9.ARPS/Noah: at Center for Analysis & Prediction of Storms (CAPS)

Improving the NCEP Mesoscale Eta Model via Land-Surface Initiatives Eta improvement goals - 2 meter air temperature and humidity - 10 meter wind vector - PBL T and Td profiles - convective stability indices - integrated moisture flux convergence - precipitation and cloud cover

Interannual variability of North American Monsoon - interior Southwest moist July 1999 July 2000 obs Eta C obs Eta July 2001 dry semi-dry 33 C Eta forecast hour 32 C Moist soil in Eta Dry soil in Eta Semi-dry soil in Eta

ETA MODEL LAND-SURFACE MODELING MILESTONES Since 1996, a series of GCIP/GAPP-sponsored land-surface model related advances have been made to the NCEP mesoscale Eta model and its Eta- based 4-D data assimilation system (EDAS). 31 Jan 1996multi-layer soil/vegetation/snow model introduced initial soil moisture/temperature from GDAS 18 Feb 1997new vegetation greenness database from NESDIS refined adjustment of initial GDAS soil moisture refined evaporation over snow and bare soil 09 Feb 1998increase from 2 to 4 soil layers (10, 30, 60, 100 cm layers) 03 Jun 1998full self-cycling of EDAS/Eta soil moisture and temperature new NESDIS daily 23-km snow cover and sea ice 15 Mar 1999 "NOAH" name designated for Eta land-surface model 01 Apr 1999GOES vs Eta skin temperature verification 24 Mar 2000Eta near-surface regional Forecast Verification System 15 Mar 2001retrospective NOAH LSM Eta/EDAS testing initiated 24 Apr 2001realtime NOAH LSM Eta/EDAS testing initiated 02 July 2001pre-implementation NOAH LSM testing in parallel Eta/EDAS 24 July 2001frozen soil physics, patchy snowcover (OHD, V. Koren) 12 Feb 2002improved sub-surface heat flux with snowpack

ETA/NOAH LAND-SURFACE MODEL UPGRADES: 24 Jul 01 - assimilation of hourly precipitation -- hourly 4-km radar/gage analysis (Stage V) -cold season processes(Koren et al 1999) -- patchy snow cover -- frozen soil (new state variable) -- snow density (new state variable) -- bare soil evaporation refinements -- parameterize upper sfc crust cap on evap - soil heat flux -- new soil thermal conductivity (Peters-Lidard et al 1998) -- under snowpack (Lunardini, 1981) -- vegetation reduction of thermal cond. (Peters-Lidard et al 1997) - surface characterization -- maximum snow albedo database (Robinson & Kukla 1985) -- dynamic thermal roughness length refinements - vegetation -- deeper rooting depth in forests -- canopy resistance refinements NOAH LSM tested in various land-model intercomparison projects, e.g., GSWP, PILPS 2a, 2c, 2d, 2e, Rhone, and (near-future) DMIP.

July 2001 NOAH LSM improvements in coupled Eta model Successfully Targeted Impacts: 1 - Cold season processes (snow melt, frozen soil) *** reduce near-surface cool bias over snow cover 2 - Early spring wet soils (soil heat flux, bare soil evaporation) *** reduce near-surface moist bias 3 - Summer over non-sparse green vegetation *** reduce near-surface warm bias

Old model formulation - cool, moist bias in 2-m T, Td New model formulation – reduced cool, moist bias Physics change: new soil thermal conductivity, nonlinear vs linear dependence of direct evap on top layer soil moisture REDUCING SURFACE MOIST-COOL BIAS OVER WET-BARE GROUND 12Z, 27 APR 2001, 60-hr model run 36-hr OLD 2-meter T=> Td=> NEW 2-meter T=> Td=> Champaign, Illinois

REDUCING SURFACE MOIST-COOL BIAS OVER WET-BARE GROUND 00Z lowest boundary- layer level (~ m) dew point temperature 48-km parallel old formulation 00Z lowest boundary-layer level (~ m) dew point temperature 48-km parallel new formulation (NOAH LSM)

REDUCING NEAR-SURFACE MOIST-COOL BIAS OVER WET-BARE GROUND IN SPRING Improved 2-m RH in 48-hour diurnal forecast cycle during Apr-May old NOAH LSM obs Eta forecast hour new NOAH LSM 2-m relative humidity (%) 66 USA northern mid-west

Shallow/retreating snow cover in USA northern plain states North America snowcover 01 Feb Feb Feb Feb Feb Feb 2001

old model formulation (upper left) => bulk of incoming energy melts/sublimates snow => skin temp held at freezing => 2-m air temp held near freezing new model formulation (upper right) => patchy snow cover for snow depth less than threshold depth (veg-type dependent) => reduces surface albedo => more available energy at sfc => skin temp can exceed 0 C => 2-m air temp rises further above freezing. REDUCING SURFACE COOL BIAS OVER MELTING SNOW FEB 2001 ETA MODEL RETROSPECTIVE RUNS warm advection/melting snowpack case: 00Z 02 FEB 2001, 60-hr model run 2-m air temp, current formulation 2-m air temp, new formulation North Platt, Neb. 0 C =0 C snow melt skin temp 2-m air temp model  0 C obs>0 C 18Z North Platt, Neb. 18Z 0 C >0 C obs,model>0 C

The new formulation has less cold bias in 2-m air temp than old operational formulation over this region of shallow melting snowpack. (obs=plotted numbers, model=color-shaded contouring; North Platt, Neb. circled) REDUCING SURFACE COOL BIAS OVER MELTING SNOW 02 FEB 2001 warm advection/melting snowpack case 18Z 2-m air temp, old formulation18Z 2-m air temp, new formulation

Mean diurnal cycle of 2-m air temperature of observations and Eta model 48-hr forecast from 12Z, averaged over 30-day WINTER period of 01 Feb – 01 Mar 2001 at all surface stations over East U.S. Station OBS: solid OPS Eta/NOAH: short dash TEST Eta/NOAH: long dash) Temperature (C) Forecast Hour

Reducing Summer warm bias over non-sparse green vegetation 00Z, 30 AUG 2000, 60-hr Eta model run OLD 2-meter T=> Td=> NEW 2-meter T=> Td=> Champaign, Illinois Solid Line: surface station observation Dashed Line: coupled Eta / NOAH model forecast Physics change: ground heat flux under vegetation, canopy resistance parameters

Forecast Hour 048 Mean diurnal cycle of 2-m air temperature of observations and Eta model 48-hr forecast from 12Z, averaged over 30-day SUMMER period of 12 Aug –12 Sep 2000 at all surface stations over East U.S. Station OBS: solid OPS Eta/NOAH: short dash TEST Eta/NOAH: long dash) Temperature (C) 17 27

2-m Air Temp Bias: 48-hr Ops Eta Forecast valid at 00Z EAST

JULY 2-m Air Temperature: EAST (Monthly mean diurnal cycle over 48-h fcst: Obs solid, model dashed)

JULY 2-m Relative Humidity (percent): EAST (Monthly mean diurnal cycle over 48-h fcst: Obs solid, model dashed)

N-LDAS Design (The Uncoupled Approach) 1. Force models with 4DDA surface meteorology (Eta/EDAS), except use actual observed precipitation (gage-only daily precip analysis disaggregated to hourly by radar product) and hourly downward solar insolation (derived from GOES satellites). 2. Use 4 different land surface models: – NOAH (NOAA/NWS/NCEP) – MOSAIC (NASA/GSFC) – VIC (Princeton U./ U. Washington) – Sacramento (NOAA/OHD) 3. Evaluate results with all available observations, including soil moisture, soil temperature, surface fluxes, satellite skin temperature, snow cover and runoff.

1)REALTIME: 15 Apr 1999 to 15 Dec NCEP realtime forcing 2)RETROSPECTIVE: 01 Oct 1996 to 30 Sep Mandated largely by spin-up issues -- NASA-assembled retrospective forcing --- Higgins NCEP/CPC reprocessed precipitation forcing: ---- more gages obs, more QC --- Pinker U.Md reprocessed solar insolation forcing ---- better cloud screening, more QC Rutgers University compared the soil moisture, soil temperature, surface flux results from the retrospective LDAS runs to observations over Oklahoma/Kansas for last retro year. LDAS Run Modes: 1) Realtime, 2) Retrospective

LDAS Model Mean Annual Evaporation (mm) over Oct 97 – Sep 99

LDAS Model Mean Annual Runoff (mm) over Oct 97 – Sep 99

NLDAS Simulated River System Upstream area [log10(km^2)] Travel time to outlet [days] Large River basins River flow direction mask

East Fork of White River at Columbus, IN

Mean annual modeled normalized model runoff bias: Oct 97-Sep 99

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Fig. 16 From Robock et al.

July 1999 April 1999 Fig. 22 SGP ARM/CART Monthly Mean Diurnal Cycle of Surface Energy Fluxes

April 1999 July 1999 Fig. 24 Monthly Mean Diurnal Cycle of Surface Skin Temperature

July 1998