Post on 17-Dec-2015
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 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)