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Land-Surface Modeling Performance At NCEP. Ken Mitchell. NCEP Environmental Modeling Center. WRF Land Working Group Workshop: 18 June 03. NCEP : Where America\'s Climate and Weather Services Begin. GAPP. GCIP. NCEP/EMC. NWS/OHD. NOAA/NESDIS. Dan Tarpley. John Schaake. Ken Mitchell

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slide1

Land-Surface Modeling Performance

At NCEP

Ken Mitchell

NCEP Environmental Modeling Center

WRF Land Working Group Workshop: 18 June 03

NCEP: Where America\'s Climate and Weather Services Begin

slide2

GAPP

GCIP

NCEP/EMC

NWS/OHD

NOAA/NESDIS

Dan Tarpley

John Schaake

Ken Mitchell

Michael Ek

Dag Lohmann

Victor Koren

Bruce Ramsay

Andy Bailey

Qingyun Duan

AFWA

George Gayno

NCAR

Jerry Wegiel

Fei Chen

Jimy Dudhia

Univ. Maryland

NASA/GSFC

COLA

Hugo Berbery

Princeton Univ.

Rachel Pinker

Paul Houser

Brian Cosgrove

Mike Fennessey

Paul Dirmeyer

Eric Wood

Justin Sheffield

Univ. Washington

Univ. Oklahoma

Rutgers Univ.

NOAA/ARL

Dennis Lettenmaier

Laura Bowling

Ken Crawford

Jeff Basara

Alan Robock

Lifeng Luo

Atmospheric

Research

NCEP/CPC

Tilden Meyers

Jon Pliem

Univ. Arizona

Alan Betts

Soroosh Sorooshian

James Shuttleworth

Luis Bastidas

Wayne Higgins

Huug Van den Dool

Collaborators

papers recently submitted to gcip special issue of jgr show vugraphs and pass out cds
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
Systems Using the Noah Land Model

OPERATIONAL SYSTEMS

  • Eta/EDAS: NCEP Eta Model and Eta Data Assimilation System
  • GFS/GDAS: NCEP Global Forecast System (older version of Noah)
  • AGRMET: Air Force Agricultural Meteorological Model (USDA)

DEMONSTRATION TESTBED SYSTEMS

  • Eta-RCM: Eta Regional Climate Model, 2-4 month seasonal fore
  • Eta R/R: Eta-based Regional Reanalysis (underway, 1979-2003)
  • GFS: NCEP Global Model (most current Noah version)
  • NLDAS Realtime: N. American Land Data Assimilation System
  • NLDAS Retrospective: 50-year by CPC (for drought monitoring)
  • GLDAS: NASA/NCEP Global Land Data Assimilation System
  • MM5/Noah: at NCAR
  • WRF/Noah: at NCAR and NCEP
  • ARPS/Noah: at Center for Analysis & Prediction of Storms (CAPS)
improving the ncep mesoscale eta model via land surface initiatives
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

slide7

Interannual variability of North American Monsoon - interior Southwest

moist

dry

30

33 C

29 C

32

32

23

24

24

16

16

16

00

00

12

12

24

24

36

36

48

48

00

12

24

36

48

July 2001

July 1999

July 2000

semi-dry

Semi-dry

soil in Eta

Moist soil

in Eta

Dry soil

in Eta

32 C

obs

obs

Eta

Eta

Eta forecast hour

slide8

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 introduced

initial soil moisture/temperature from GDAS

18 Feb 1997 new vegetation greenness database from NESDIS

refined adjustment of initial GDAS soil moisture refined

evaporation 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 ice

15 Mar 1999 "NOAH" name designated for Eta land-surface model

01 Apr 1999 GOES vs Eta skin temperature verification

24 Mar 2000 Eta near-surface regional Forecast Verification System

15 Mar 2001 retrospective NOAH LSM Eta/EDAS testing initiated

24 Apr 2001 realtime NOAH LSM Eta/EDAS testing initiated

02 July 2001 pre-implementation NOAH LSM testing in parallel

Eta/EDAS

24 July 2001 frozen soil physics, patchy snowcover (OHD, V. Koren)

12 Feb 2002 improved sub-surface heat flux with snowpack

slide9

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.

slide11

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

slide12

REDUCING SURFACE MOIST-COOL BIAS

OVER WET-BARE GROUND

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

OLD

2-meter

T=>

Td=>

NEW

2-meter

T=>

Td=>

Champaign, Illinois

36-hr

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

slide13

REDUCING SURFACE MOIST-COOL BIAS

OVER WET-BARE GROUND

00Z lowest boundary-layer

level (~ 100-150 m)

dew point temperature

48-km parallel

new formulation (NOAH LSM)

00Z lowest boundary-layer

level (~ 100-150 m)

dew point temperature

48-km parallel

old formulation

slide14

00

12

24

36

48

REDUCING NEAR-SURFACE MOIST-COOL BIAS

OVER WET-BARE GROUND IN SPRING

84

old

NOAH

LSM

USA northern mid-west

new

NOAH

LSM

75

2-m relative humidity (%)

66

57

obs

Eta forecast hour

Improved 2-m RH in 48-hour diurnal forecast cycle during Apr-May

slide15

North America

snowcover

01 Feb 2001

02 Feb 2001

03 Feb 2001

04 Feb 2001

05 Feb 2001

06 Feb 2001

Shallow/retreating snow cover in USA northern plain states

slide16

REDUCING SURFACE COOL BIAS OVER MELTING SNOW

FEB 2001 ETA MODEL RETROSPECTIVE RUNS

snow

melt

North Platt, Neb.

North Platt, Neb.

=0 C

>0 C

skin

temp

obs>0 C

2-m air

temp

0 C

0 C

obs,model>0 C

model0 C

18Z

18Z

2-m air temp, new formulation

2-m air temp, current formulation

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

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.

slide17

REDUCING SURFACE COOL BIAS OVER MELTING SNOW

02 FEB 2001 warm advection/melting snowpack case

18Z 2-m air temp, old formulation

18Z 2-m air temp, new formulation

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)

slide18

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: solidOPS Eta/NOAH: short dashTEST Eta/NOAH: long dash)

+5

Temperature (C)

-3

0

48

Forecast Hour

slide19

Reducing Summer warm bias over non-sparse green vegetation

00Z, 30 AUG 2000, 60-hr Eta model run

Champaign, Illinois

OLD

2-meter

T=>

Td=>

NEW

2-meter

T=>

Td=>

Solid Line: surface station observation

Dashed Line: coupled Eta / NOAH model forecast

Physics change: ground heat flux under vegetation, canopy resistance parameters

slide20

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: solidOPS Eta/NOAH: short dashTEST Eta/NOAH: long dash)

27

Temperature (C)

17

0

48

Forecast Hour

slide22

JULY 2-m Air Temperature: EAST

(Monthly mean diurnal cycle over 48-h fcst: Obs solid, model dashed)

slide23

JULY 2-m Relative Humidity (percent): EAST

(Monthly mean diurnal cycle over 48-h fcst: Obs solid, model dashed)

slide24

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.
slide25

LDAS Run Modes:1) Realtime, 2) Retrospective

  • REALTIME: 15 Apr 1999 to 15 Dec 2001
    • -- NCEP realtime forcing
  • 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.
nldas simulated river system
NLDAS Simulated River System

Upstream area [log10(km^2)]

Travel time to outlet [days]

River flow direction mask

Large River basins

slide31

*

*

*

*

slide33

Fig. 16

From Robock et al.

slide34

April 1999

July 1999

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

slide35

April 1999

July 1999

Fig. 24 Monthly Mean Diurnal Cycle of Surface Skin Temperature

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