Initial Results from the Diurnal Land/Atmosphere Coupling Experiment (DICE)

1. Initial Results from the Diurnal Land/Atmosphere Coupling Experiment (DICE) Weizhong Zheng, Michael Ek, Ruiyu Sun, Jongil Han, Jiarui Dong and Helin Wei NOAA/NCEP/EMC, College Park, MD 20740, USA DICE Workshop UK Met Office, Exeter, 14-16 October 2013

2. OBJECTIVES • DICE Objective:Make an assessment of the impact of land-atmosphere feedbacks by first assessing the land and single-column atmosphere models separately, constrained by observational data, and then identifying changes due to coupling (DICE Project, 2013). • Examine the performance of NCEP SCM (GFS) and Noah land surface model with the DICE data set. • (1) OBS ==> Noah or SCM (Stage 1a and 1b) • (2) SCM and Noah coupled to include the land/atmos feedbacks (Stage 2)

3. NCEP SCM (GFS) • NCEP GFS: Global Forecast System • Resolution: T-574 (1760x880) / T190 (576x288) • Vertical levels: 64 (~22m for the lowest model level) • Time step: 7.5 min • PBL scheme: MRF PBL (Troen and Mahrt, 1986; Hong and Pan, 1996) • Land surface processes: Noah V2.7 (Michael Ek et al., 2003) • Radiation scheme: • LW—Rapid Radiative Transfer Model (AER, Mlawer et al. 1997) • SW-- Rapid Radiative Transfer Model version 2 (AER). • Convection scheme: Deep convection and shallow convection

4. NCEP-NCAR unified Noah land model • Surface energy (linearized) & water budgets; 4 soil layers. • Forcing: downward radiation, precip., temp., humidity, pressure, wind. • Land states: Tsfc, Tsoil*, soil water* and soil ice, canopy water*, snow depth and snow density. *prognostic • Land data sets: veg. type, green vegetation fraction, soil type, snow-free albedo & maximum snow albedo. • Noah coupled with NCEP models: North American Mesoscale model (NAM; short-range), Global Forecast System (GFS; medium-range), Climate Forecast System (CFS; seasonal), & other NCEP modeling systems (i.e. NLDAS & GLDAS).

5. Noah Setup • Some related parameters setup in the Noah • Veg type: 12 (Cultivations, SiB-1 veg. class categories) • Soil type: 2 (Silty clay loam, Zobler soil class categoreis) • Albedo: 0.211 • GVF: 0.39 • Emissivity: 1.0 • Z0: 0.3951 (m) • Rsmin: 40

6. DICE: Diurnal land/atmosphere coupling experiment --- Noah off-line run Model: Noah v2.7 Case: CASES-99 field experiment in Kansas; 3 days: 19UTC Oct. 23 – 19 UTC Oct. 26, 1999 First Stage: EXP: Noah_Offline OBS => Noah Obs atmos forcing ==> Noah 3 days: 19UTC Oct. 23 – 19 UTC Oct. 26, 1999

7. Comparison of surface fluxes between simulation and observation Too large latent heat flux simulated by Noah during daytime, compared with the observation. Black: Observation Red : Simulation (OBS ==>Noah)

8. Comparison of surface momentum fluxes (u- and v-component) Black: Observation Red : Simulation (OBS ==>Noah)

9. Comparison of upward SW and LW at the surface Black: Observation Red : Simulation (Obs ==> Noah) ( albedo=0.211; emissivity=1.0 )

10. Comparison of Tskin between simulation and observation The surface skin temperature simulated by Noah is about 5-7 degrees lower than the observation during daytime. Black: Observation Red : Simulation (OBS ==>Noah)

11. DICE: Diurnal land/atmosphere coupling experiment --- SCM (GFS) with Noah Models: SCM (GFS v2010) (Noah v2.7) (Ruiyu Sun, PBL team) Case: CASES-99 field experiment in Kansas; 3 days: 19UTC Oct. 23 – 19 UTC Oct. 26, 1999 First Stage: EXP: SCM_Obs ; OBS => SCM Obs sfc fluxes & Large-scale atmos forcing ==> SCM Second Stage: EXP: SCM_Noah SCM coupled with Noah including the land/atmos feedbacks.

12. Large atmospheric forcing for SCM provided by the DICE data set Horizontal advection heat rate Horizontal advection moisture change

13. Large atmospheric forcing for SCM provided by the DICE data set Horizontal advection u-comp change Horizontal advection v-comp change

14. Comparison of simulated temperature profiles SCM_Obs: SCM driven by observed sfc fluxes & large-scale atmos forcing SCM_Noah: SCM coupled with Noah including the land/atmos feedbacks.

15. Comparison of simulated specific humidity profiles High simulated moisture near the surface SCM_Obs: SCM driven by observed sfc fluxes & large-scale atmos forcing SCM_Noah: SCM coupled with Noah including the land/atmos feedbacks.

16. Comparison of simulated u-component profiles SCM_Obs: SCM driven by observed sfc fluxes & large-scale atmos forcing SCM_Noah: SCM coupled with Noah including the land/atmos feedbacks.

17. Comparison of simulated v-component profiles SCM_Obs: SCM driven by observed sfc fluxes & large-scale atmos forcing SCM_Noah: SCM coupled with Noah including the land/atmos feedbacks.

18. Comparison of vertical diffusion heat rates SCM_Obs: SCM driven by observed sfc fluxes & large-scale atmos forcing SCM_Noah: SCM coupled with Noah including the land/atmos feedbacks.

19. Comparison of vertical diffusion moisture change rates SCM_Obs: SCM driven by observed sfc fluxes & large-scale atmos forcing SCM_Noah: SCM coupled with Noah including the land/atmos feedbacks.

20. Comparison of vertical diffusion du/dt SCM_Obs: SCM driven by observed sfc fluxes & large-scale atmos forcing SCM_Noah: SCM coupled with Noah including the land/atmos feedbacks.

21. Comparison of vertical diffusion dv/dt SCM_Obs: SCM driven by observed sfc fluxes & large-scale atmos forcing SCM_Noah: SCM coupled with Noah including the land/atmos feedbacks.

22. Comparison of simulated PBL height High PBL height ? SCM_Obs: SCM driven by observed sfc fluxes & large-scale atmos forcing SCM_Noah: SCM coupled with Noah including the land/atmos feedbacks.

23. Comparison of surface fluxes between simulation and observation Too large latent heat flux simulated by Noah during daytime, compared with the observation. Black: Observation Red : Simulation from SCM_Noah

24. Comparison of surface momentum fluxes Black: Observation Red : Simulation from SCM_Noah

25. Comparison of upward SW and LW at the surface Lower upward LW at the surface because of lower simulated skin temperature during daytime. Black: Observation Red : Simulation from SCM_Noah

26. Comparison of surface skin temperatures Tskin from Noah off-line driven by the observed atmospheric forcing. Black: Observation Red : Simulation from SCM_Noah

27. Summary: • The NCEP SCM (GFS) coupled with Noah land surface model was examined with the DICE data set, and the result shows as follows: • 1) The Noah off-line run driven by the observed atmospheric forcing shows that the Noah model can reasonably capture the surface momentum and sensible heat fluxes but substantially overestimate the latent heat flux and underestimate the surface skin temperature during daytime; • 2) The SCM coupled with Noah run shows that the higher moisture near the surface because of higher latent heat flux, compared with the SCM run driven by observed surface fluxes and large-scale atmospheric forcing • Future: (a) Ensemble runs: - Use set of sfc fluxes derived by other LSMs to drive NCEP SCM; - Use set of atmos derived by other SCMs to drive Noah. (b) Investigate parameterization schemes related to the surface fluxes in NCEP SCM and Noah land surface model as well as their coupling.

28. Thank you! Questions?