The evaluation of coupled WRF + Noah-MP and 1-d offline Noah-MP at the FLUXNET sites over Canada

Transcription

1 The evaluation of coupled WRF + Noah-MP and 1-d offline Noah-MP at the FLUXNET sites over Canada Yanping Li, Liang Chen Univ of Saskatchewan Fei Chen, NCAR Alan Barr, Environment Canada

2 I. The calibration of 1-d offline Noah-MP + organic layer at BERMS Old Aspen Site: Site Description Old Aspen site (53.7 o N, o W, altitude 601 m) - a mature deciduous broadleaf forest at the southern edge of the Canadian boreal forest in Saskatchewan. Soil - an Orthic Gray Luvisol with an 8-10 cm deep surface organic LFH horizon overlying a loam to sandy clay loam mineral soil. 30% of the fine roots are in the LFH horizon and 60% are in the upper 20 cm of mineral soil. Mean annual air temperature ~ 1.5 o C, mean precipitation ~ 406 mm at OA during the study period ( ).

3 I. The calibration of 1-d Noah-MP +organic layer at BERMS Old Aspen Site: Monthly air temperature above canopy and precipitation Drought Wet Experiment Design: Noah-MP offline simulation Control (CTL) versus Incorporated organic soil experiment (OGN). Dry period ( ) versus Wet period ( )

4 Noah-MP (Multi-Parameterization) 1. Vegetation model (prescribed; dynamic; calculate FVEG; shdfac=maximum) 4 2. Canopy stomatal resistance (Jarvis; Ball-Berry) 2 3. Soil moisture stress factor for transpiration (Noah;SSiB;CLM) 3 4. Runoff and groundwater (SIMGM; SIMTOP; Schaake96; BATS) 4 5. Surface layer drag coeff (CH & CM) (M-O; Chen97) 2 6. Supercooled liquid water (NY06; Koren99) 2 7. Frozen soil permeability (NY06; Koren99) 2 8. Radiation transfer (gap=f(3d,cosz); gap=0; gap=1--fveg) 3 9. snow surface albedo (BATS; CLASS) 2 10.rainfall & snowfall (Jordan91; BATS; Noah) 3 11.lower boundary of soil temperature (zero-flux; Noah) 2 12.snow/soil temperature time scheme (semi-implicit; fully implicit) 2 Thousands of combinations Niu et al. (2011)

5 Incorporating Organic Soil layer in Noah-MP Thermal conductivity of soil solids Unforzen saturated thermal conductivity Dry soil thermal conductivity Soil solid heat capacity 2.5E E+6 Saturated volumetric water content Saturated hydraulic conductivity 1.0E E-5 Saturated matric potential Clapp and Hornberger parameter Lawrence, D. M., and A. G. Slater (2008), Incorporating organic soil into a global climate model,climate Dynamics, 30(2-3),

6 Observed versus simulated sensible and latent heat flux above canopy SH LH CTL SH LH OGN

7 Observed and Noah-MP-simulated monthly soil temperature

8 Observed and Noah-MP-simulated monthly soil moisture

9 I. The calibration of 1-d offline Noah-MP + organic layer at BERMS Old Aspen Site: Conclusions Chen L., Yanping Li, F. Chen, A. Barr, M. Barlage, B. Wan, 2015: The incorporation of an organic soil layer in the Noah-MP Land Surface Model and its evaluation over a Boreal Aspen Forest, Atmospheric Chemistry and Physics, in review» Given the important role of boreal forests in regional climate by reducing winter albedo and also acting as a carbon sink and water source to the atmosphere and differences in forest structures and soils in the general boreal ecosystem, this work is for the first time that Noah land-surface model (Noah-MP) is used to investigate impact of parameterizing organic soil on simulated surface energy and water cycle components at a boreal forest site.» The verification results against site show that including an organic-soil parameterization within the Noah-MP model can significantly improve performance of the model in surface energy and hydrology simulation due to the lower thermal conductivity and greater porosity of the organic soil.» The effects of including an organic soil parameterization are more significant for drought years. Including an organic-soil parameterization within the Noah-MP model can substantially modified the partition between direct soil evaporation and vegetation transpiration in the simulation. For wet years, the impact of the organic soil on subsurface runoff is substantive with much higher runoff throughout the season.

10 WRF-4km CONUS Domain

11 II. Offline 1-d Noah-MP vs coupled WRF+Noah-MP at FLUXNET sites: Objectives» Use the BERMS Old Aspen site observations to evaluate the offline 1-d Noah-MP model, as well as 4-km continental WRF (coupled with Noah-MP) simulated energy fluxes. Uncertainties in energy and water fluxes in land surface models (LSMs) arise from the meteorological inputs (Santanello et al., 2009), as well as the choice of schemes used to represent land surface and boundary layer processes (Sellers et al., 1997; Overgaard et al., 2006; Dickinson, 2011).» Initial condition error: analyze the biases in meteorology input. Offline 1-d Noah-MP (no error) vs coupled WRF+Noah-MP (with error)» Model error: analyze the model errors in the simulation of energy fluxes. Systematic errors exist in both offline 1-d Noah-MP and coupled WRF+Noah-

12 II. Offline 1-d Noah-MP vs coupled WRF+Noah-MP at BERMS Old Aspen site: Forcing

13 II. Offline 1-d Noah-MP vs coupled WRF+Noah-MP at BERMS Old Aspen site: Simulated Surface Energy Flux

14 II. Offline 1-d Noah-MP vs coupled WRF+Noah-MP at BERMS Old Aspen site: Simulated Soil Temperature 0-10 cm cm cm

15 II. Offline 1-d Noah-MP vs coupled WRF+Noah-MP at BERMS Old Aspen site: Simulated Soil Moisture 0-10 cm cm cm

16 II. Offline 1-d Noah-MP vs coupled WRF+Noah-MP at BERMS Old Aspen site: Simulated Annual Cycle

17 Our plan I. Evaluate the performance of Noah-MP 1-d offline simulation and the coupled WRF+Noah-MP simulation at other FLUXNET sites. II. Examine the difference between FLUXNET sites representing different land cover, their observations and the coupled WRF+Noah-MP simulations (from 4- km CONUS WRF historical run).» Next step: How land use change especially at Boreal forest region will feed back to regional climate through land-atmosphere interaction.