THE EFFECT OF THE SURFACE CHARACTERISTICS

ON THE DICE RESULTS SEEN BY THE MESONH MODEL

M. A. Jiménez, P. Le Moigne and J. Cuxart

DICE workshop, 14-16 October 2013, Exeter (UK)

DIurnal land/atmosphere Coupling Experiment (DICE)DIurnal land/atmosphere Coupling Experiment (DICE)CASES – 99 experiment: 23-26 October 1999CASES – 99 experiment: 23-26 October 1999

released May 2013, preliminary results October 2013released May 2013, preliminary results October 2013

Photograph taken at the CASES-99 experiment (Southern Great Plains, USA)

Model Contact scientist

Institute Stages submitted

Levels Sensitivity tests

Arome Eric Bazille Meteo France All 60/70 resolution

Arpege Eric Bazille Meteo France All 60/70 resolution

ECEARTH Reinder Ronda Wageningen SCM only 91 LAI

GDPS3.0 Ayrton Zadra CMC All 79

GFDL Sergey Malyshev Princeton All 24

GISS_E2 Ann Fridlind, Andy Ackerman

GISS All 40

IFS/HTESSEL Irina Sandu, Gianpaolo Balsamo

ECMWF All 137 LAI

MESO_NH Maria A. Jimenez, Patrick Le Moigne, Joan Cuxart

IMEDEA, Meteo France, UIB

All 85 Bare soil, rooth depth

UM/JULES Adrian Lock, Martin Best

Met Office All 70 Vegetation

WRF-NOAH Weiguo Wang NUIST All 60 Lots!

WRF Wayne Angevine NOAA ? 119 PBL scheme

CAM5, CLM4 David Lawrence NCAR 1a, 1b ?

PBCM Pierre Gentine Columbia Not yet

MODEL PARTICIPANTSMODEL PARTICIPANTS

Stage 1bStage 1b

H, LE, RN, LST

Atmosphere- SCM

Surface - prescribed

Stage 1aStage 1a

ISBA (3 layers)

Atmosphere - prescribed

Surface - SURFEX

T,wind,q at 55mT,wind,q at 10m

Stage 2Stage 2

SCM + SURFEX (coupling)

Stage 3Stage 3

As Stages 1a and 1b but prescribing 12 different forcings (SCM and SURFEX)

Atmosphere- SCM

Surface - SURFEX

INITIAL CONDITIONSINITIAL CONDITIONS

wind speed(m/s)

potential temperature

(K)

specific humidity

(g/kg)

SCM - INITIAL PROFILES (sounding at 12 LT, 1900 UTC)

T Q

WIND

LSM - INITIAL CONDITIONS(evolution of T, q and windduring the simulated period)

SCM: MesoNH model (Lafore et al., 1998)

Turbulence (Cuxart et al., 2000), length scale (Bougeault and Lacarrere 1989)Radiation (ECMWF code called every time-step)Kessler microphysical scheme (vapor, cloud water and rain)Time step (300s for SCM and 20s for coupled runs)Vertical grid (Cuxart et al., 2007): 85 levels (3m resolution at lower levels, gradual stretching)

LSM: SURFEX (Masson et al., 2013)

ISBA 3 layersLand use: Ecoclimap at 1km resolution (Masson et al., 2003)

50% great plains crops and 50% rockies grasslandtotal vegetation fraction over the pixel = 0.73

root depth = 1.5m and total depth = 2m leaf area index = 1.46CLAY=0.24, SAND=0.38 from Harmonized World Soil Database (HWSD) at 1km resolution

RN

H LE

G

SURFACE ENERGY BUDGET (W/m2)SURFACE ENERGY BUDGET (W/m2)

INT TURBINT RAD

Steeneveld et al 2006

M10m (m/s)

T2m (K)

TIME SERIESTIME SERIES

Q2m (kg/kg)

observations in green

* the wind speed is well captured

* differences in T of 4-5K during day/night but CPL match better to the observations

* CPL run too humid → large LE

SCM – STAGE 1B SCM + SURFACE – STAGE 2LLJ well captured-> large-scale advection

CPL run too humid

SCM – STAGE 1B SCM + SURFACE – STAGE 2

H largerH largerLE smallerLE smallerT warmerT warmer(lower levels)(lower levels)

H smallerH smallerLE largerLE largerT colderT colder(lower levels)(lower levels)

VEGETATION ROOT DEPTH

default 50% bare 50% vegetated

sfc=1cm, root=1.5m, total=2m

BARE 100% bare0 % vegetated

sfc=1cm, root=1.5m, total=2m

ROOT 50% bare50% vegetated

sfc=1cm, root=0.4m, total=0.6m

SENSITIVITY TESTSSENSITIVITY TESTS

LATENT HEAT FLUX (W/m2)

TESTING THE SURFACE SCHEMETESTING THE SURFACE SCHEME

SENSIBLE HEAT FLUX (W/m2)

RN (W/m2)

observations in red, equivalent to SCM

SCM = root depth

SCM = bare soil

TESTING THE SCM modelTESTING THE SCM model

RN

LE

H

SCM = root depth

SCM = bare soilSCM results (1b) agree with SURFEX results (1a)

TESTING THE SCM modelTESTING THE SCM model

10m wind speed (m/s)

2m specific humidity (kg/kg)

2m temperature (K)observations in blue

* no impact on the wind speed* impact on the T and q* q(bare ground) similar to obs.

SENSITIVITY TESTS SENSITIVITY TESTS vertical resolution (SCM, Stage 1b only)vertical resolution (SCM, Stage 1b only)

default: 85 levels (3m at lower levels)test: 60 levels (10m at lower levels)

SENSITIVITY TESTS SENSITIVITY TESTS vertical resolutionvertical resolution

60 levels 85 levels (DICE)

wind speed (m/s)

potentialtemperature(K)

1-2 K difference

RN

H LE

Stage 3a results (SCM)Stage 3a results (SCM)12 forcings as stage 1b12 forcings as stage 1b

hight & low values hight & low values

Preliminary resultsPreliminary resultsStage 1b Stage 1b (near surface evolution)(near surface evolution)

20m 55m

Preliminary resultsPreliminary resultsStage 1b Stage 1b (potential temperature)(potential temperature)

SUMMARY

1) SCM vs CPL * CPL is giving larger LE and smaller H than SCM

* CPL has more specific humidity than SCM

2) reducing the percentage of vegetation * Improve LE and H become closer to observations * As a test case, bare ground soil is taken but this is far from the reality...

3) reducing the root depths to a more realistic values * Improve H and LE is closer to observations * more realistic case, by default the root depth is too high

4) vertical grid mesh* importance to properly reproduce the surface layer characteristics

DICE siteDICE site

EASY CASE!EASY CASE!surface and tower observations (model validation) surface and tower observations (model validation) clear-skies, flat, homogeneous, …clear-skies, flat, homogeneous, …

SURFACE CHARACTERISTICS in the modelSURFACE CHARACTERISTICS in the modelcovered by dry vegetationcovered by dry vegetation

But still difficult for models …But still difficult for models …(introduce the concept of died vegetation)(introduce the concept of died vegetation)

ACKNOWLEDGEMENTS

RESEARCH PROJECT CGL2012-37416-C04-01

JAE-DOC contract