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, October 2013, Exeter (UK)

DIurnal land/atmosphere Coupling Experiment (DICE) CASES – 99 experiment: October 1999 released May 2013, preliminary results October 2013 Photograph taken at the CASES-99 experiment (Southern Great Plains, USA)

ModelContact scientist InstituteStages submitted LevelsSensitivity tests AromeEric BazilleMeteo FranceAll60/70resolution ArpegeEric BazilleMeteo FranceAll60/70resolution ECEARTHReinder RondaWageningenSCM only91LAI GDPS3.0Ayrton ZadraCMCAll79 GFDLSergey MalyshevPrincetonAll24 GISS_E2Ann Fridlind, Andy Ackerman GISS All40 IFS/HTESSELIrina Sandu, Gianpaolo Balsamo ECMWFAll137LAI MESO_NHMaria A. Jimenez, Patrick Le Moigne, Joan Cuxart IMEDEA, Meteo France, UIB All85Bare soil, rooth depth UM/JULESAdrian Lock, Martin Best Met OfficeAll70Vegetation WRF-NOAHWeiguo WangNUISTAll60Lots! WRFWayne AngevineNOAA?119PBL scheme CAM5, CLM4David LawrenceNCAR1a, 1b? PBCMPierre GentineColumbiaNot yet MODEL PARTICIPANTS

Stage 1b H, LE, RN, LST Atmosphere- SCM Surface - prescribed Stage 1a ISBA (3 layers) Atmosphere - prescribed Surface - SURFEX T,wind,q at 55m T,wind,q at 10m Stage 2 SCM + SURFEX (coupling) Stage 3 As Stages 1a and 1b but prescribing 12 different forcings (SCM and SURFEX) Atmosphere- SCM Surface - SURFEX

INITIAL 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 wind during 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 layers Land use: Ecoclimap at 1km resolution (Masson et al., 2003) 50% great plains crops and 50% rockies grassland total vegetation fraction over the pixel = 0.73 root depth = 1.5m and total depth = 2m leaf area index = 1.46 CLAY=0.24, SAND=0.38 from Harmonized World Soil Database (HWSD) at 1km resolution

RN H LE G SURFACE ENERGY BUDGET (W/m2) INTTURBINTRAD Steeneveld et al 2006

M10m (m/s) T2m (K) TIME 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 1BSCM + SURFACE – STAGE 2 LLJ well captured-> large-scale advection CPL run too humid

SCM – STAGE 1BSCM + SURFACE – STAGE 2 H larger LE smaller T warmer (lower levels) H smaller LE larger T colder (lower levels)

VEGETATIONROOT DEPTH default 50% bare 50% vegetated sfc=1cm, root=1.5m, total=2m BARE 100% bare 0 % vegetated sfc=1cm, root=1.5m, total=2m ROOT50% bare 50% vegetated sfc=1cm, root=0.4m, total=0.6m SENSITIVITY TESTS

LATENT HEAT FLUX (W/m2) TESTING 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 model RN LE H SCM = root depth SCM = bare soil SCM results (1b) agree with SURFEX results (1a)

TESTING 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 vertical resolution (SCM, Stage 1b only) default: 85 levels (3m at lower levels) test: 60 levels (10m at lower levels)

SENSITIVITY TESTS vertical resolution 60 levels 85 levels (DICE) wind speed (m/s) potential temperature (K) 1-2 K difference

RN H LE Stage 3a results (SCM) 12 forcings as stage 1b hight & low values

Preliminary results Stage 1b (near surface evolution) 20m55m

Preliminary results Stage 1b (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 site EASY CASE! surface and tower observations (model validation) clear-skies, flat, homogeneous, … SURFACE CHARACTERISTICS in the model covered by dry vegetation But still difficult for models … (introduce the concept of died vegetation)

ACKNOWLEDGEMENTS RESEARCH PROJECT CGL C04-01 JAE-DOC contract