Land-Surface Modeling PerformanceAt NCEP

NCEP: Where America's Climate and Weather Services Begin

WRF Land Working Group Workshop: 18 June 03

Ken MitchellNCEP Environmental Modeling Center

CollaboratorsGAPP GCIP

Eric WoodJustin Sheffield

Princeton Univ.

Dan TarpleyNOAA/NESDIS

Bruce RamsayAndy Bailey

Soroosh SorooshianJames ShuttleworthLuis Bastidas

Univ. Arizona

Dennis LettenmaierLaura Bowling

Univ. Washington

George GaynoAFWA

Jerry WegielWayne HigginsHuug Van den Dool

NCEP/CPC

Ken MitchellMichael EkDag Lohmann

NCEP/EMC

Rachel PinkerHugo Berbery

Univ. Maryland

Ken CrawfordJeff Basara

Univ. Oklahoma

Alan RobockLifeng Luo

Rutgers Univ.

John SchaakeVictor KorenQingyun Duan

NWS/OHD

Tilden MeyersJon Pliem

NOAA/ARL

AtmosphericResearch

Alan Betts

Paul HouserBrian Cosgrove

NASA/GSFC

Fei ChenJimy Dudhia

NCAR

Mike FennesseyPaul 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 ModelSystems Using the Noah Land ModelOPERATIONAL 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, 1979-2003)

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 MesoscaleEta 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

00 2412 36 48

29 C

16

23

30

16

24

32

00 2412 36 48

obs

Eta

July 2001

dry semi-dry

33 C

Eta forecast hour

32 C

00 2412 36 4816

24

32

Moist soilin Eta

Dry soilin Eta

Semi-drysoil 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 1996 multi-layer soil/vegetation/snow model introducedinitial soil moisture/temperature from GDAS

18 Feb 1997 new vegetation greenness database from NESDISrefined adjustment of initial GDAS soil moisture refinedevaporation over snow and bare soil

09 Feb 1998 increase from 2 to 4 soil layers (10, 30, 60, 100 cm layers)03 Jun 1998 full self-cycling of EDAS/Eta soil moisture and temperature

new NESDIS daily 23-km snow cover and sea ice15 Mar 1999 "NOAH" name designated for Eta land-surface model01 Apr 1999 GOES vs Eta skin temperature verification24 Mar 2000 Eta near-surface regional Forecast Verification System15 Mar 2001 retrospective NOAH LSM Eta/EDAS testing initiated24 Apr 2001 realtime NOAH LSM Eta/EDAS testing initiated02 July 2001 pre-implementation NOAH LSM testing in parallel

Eta/EDAS24 July 2001 frozen soil physics, patchy snowcover (OHD, V. Koren)12 Feb 2002 improved 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, TdNew model formulation – reduced cool, moist biasPhysics change: new soil thermal conductivity, nonlinear vs linear dependence of direct evap on top layer soil moisture

REDUCING SURFACE MOIST-COOL BIASOVER WET-BARE GROUND

12Z, 27 APR 2001, 60-hr model run

36-hr

OLD2-meter

T=>

Td=>

NEW2-meter

T=>

Td=>

Champaign, Illinois

REDUCING SURFACE MOIST-COOL BIAS

OVER WET-BARE GROUND

00Z lowest boundary-layerlevel (~ 100-150

m) dew point

temperature48-km parallel

old formulation

00Z lowest boundary-layerlevel (~ 100-150 m)

dew point temperature48-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

oldNOAHLSM

obs

Eta forecast hour00 2412 36 48

57

84

75 newNOAHLSM

2-m

rela

tive h

um

idit

y (

%)

66

USA northern mid-west

Shallow/retreating snow cover in USA northern plain states

North Americasnowcover

01 Feb 2001 02 Feb 2001 03 Feb 2001

04 Feb 2001 05 Feb 2001 06 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 SNOWFEB 2001 ETA MODEL RETROSPECTIVE RUNS

warm advection/melting snowpack case: 00Z 02 FEB 2001, 60-hr model run

2-m air temp, current formulation2-m air temp, new formulation

North Platt, Neb.

0 C

=0 C

snowmelt

skintemp

2-m airtemp

model0 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)T

emp

erat

ure

(C)

Forecast Hour0 48

-3

+5

Reducing Summer warm bias over non-sparse green vegetation00Z, 30 AUG 2000, 60-hr Eta model run

OLD2-meter

T=>

Td=>

NEW2-meter

T=>

Td=>

Champaign, Illinois

Solid Line: surface station observationDashed Line: coupled Eta / NOAH model forecastPhysics change: ground heat flux under vegetation, canopy resistance parameters

Forecast Hour0 48

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)T

emp

erat

ure

(C)

17

27

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

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 2001

-- NCEP realtime forcing

2) RETROSPECTIVE: 01 Oct 1996 to 30 Sep 99

-- 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 SystemNLDAS Simulated River SystemUpstream 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

*

**

*

LDAS Monthly Evaporation Over Northeast CONUS

0

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Sacramento

LDAS Monthly Evaporation Over Southwest CONUS

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LDAS Monthly Evaporation Over Northwest CONUS

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ct-9

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LDAS Monthly Evaporation Over Southeast CONUS

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VIC

Sacramento

Fig. 16From Robock et al.

July 1999 April 1999

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

April 1999July 1999

Fig. 24 Monthly Mean Diurnal Cycle of Surface Skin Temperature

July 1998