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Application of the Canadian Land Surface Scheme (CLASS) to Modelling the Mackenzie River Basin

Application of the Canadian Land Surface Scheme (CLASS) to Modelling the Mackenzie River Basin. D. Verseghy 1 , P. Bartlett 1 , M. Mackay 1 and E.D. Soulis 2 1 Meteorological Service of Canada, Climate Research Branch 2 University of Waterloo. The Mackenzie GEWEX Study.

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Application of the Canadian Land Surface Scheme (CLASS) to Modelling the Mackenzie River Basin

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  1. Application of the Canadian Land Surface Scheme (CLASS) to Modelling the Mackenzie River Basin D. Verseghy1, P. Bartlett1, M. Mackay1 and E.D. Soulis2 1 Meteorological Service of Canada, Climate Research Branch 2 University of Waterloo

  2. The Mackenzie GEWEX Study • Aims to improve our understanding of the water and energy cycle of the Mackenzie River Basin in particular and of cold regions in general • A major objective: to develop coupled models of atmospheric and hydrological processes. • Includes researchers from both Canadian university and government laboratories • Started 1996; completion in 2005 • Enhanced observing period carried out in 1998-99 water year

  3. Mackenzie River Basin • Covers 1.8 million km2 • Major source of fresh water for the Arctic Ocean • 75% underlain by continuous or discontinuous permafrost • Location of largest observed warming trend over past decades in the Northern Hemisphere

  4. Model runs performed using the Canadian Regional Climate Model (CRCM) • Domain located over western Canada and adjacent areas, centred on the Mackenzie • CRCM driven at the boundaries by operational analyses from Canadian Meteorological Centre • Horizontal resolution 51 km; 29 vertical levels • Standard CGCM physical parameterization package used (for radiation transfer, convection, cloud processes, etc,), including CLASS version 2.7 as land surface scheme • Simulation length: April 1997 – August 2000

  5. Surface Datasets 1-km resolution land cover database from Canadian Centre for Remote Sensing used over Canada; USGS and Olson data used for other land areas Soil data from Soil Landscapes of Canada database, and from USGS data for areas outside of Canada Deep soil moisture initialized to field capacity; deep soil temperature to annual average

  6. 3rd LAYER OF SOIL, OVER MODEL DOMAIN AT 1 KM RESOLUTION

  7. Originally developed for the CGCM; • treats fluxes of energy and water at the • land surface (Verseghy, 2000) The Canadian Land Surface Scheme (CLASS) Thermally separate vegetation canopy, snow cover and three soil layers. Four main vegetation structural types identified (needleleaf trees, broadleaf trees, crops and grass); parameters are aggregated at each time step to define representative canopy characteristics. Up to four subareas allowed over each model grid cell: vegetation covered, bare soil, snow with vegetation and snow over bare soil. One soil type for each grid cell.

  8. CANGRID (1388 mm) CRCM (1404 mm) P (mm) 09/97 09/98 09/99 09/00 Precipitation: 1997/09 – 2000/08 Overall magnitude and timing are good, although local spatial anomalies are evident. (Note, however, that the observing network is sparse, especially towards the north of the basin.) Observed climate data (CANGRID) are obtained by interpolation from weather station records over the modelling period.

  9. CANGRID (4.2 oC) CRCM (3.6 oC) Tmax (oC) 09/97 09/98 09/99 09/00 Tmax: 1997/09 – 2000/08 • Mean annual Tmax • well distributed but • seasonal amplitude • too large.

  10. CANGRID (-6.0 oC) CRCM (-8.7 oC) Tmin (oC) 09/97 09/98 09/99 09/00 Tmin: 1997/09 – 2000/08 • Significant cold bias • fall-winter throughout

  11. SWE and P CRCM P CANGRID P CRCM SWE SSM/I SWE Snow Cover Fraction NOAA CRCM SSM/I • Cumulative precipitation and SWE • over coniferous forest (Oct 1 – Jul 1) • Cold, wet bias in October evident in • SWE over entire season • As above but accumulations from • Nov 1. • Observed and modelled precip and • SWE all agree well during snowpack • accumulation season (apart from • noise in SSM/I derived SWE). • This indicates little if any snowpack • sublimation

  12. CLASS version 3.0 • New soil evaporation formulation • Ability to model organic/peat soils • New vegetation stomatal resistance formulation • Ability to model lateral flow of water in soils and streamflow • Improved snow density and interception algorithms • Improved treatment of turbulent fluxes from vegetation canopies • Mosaic modelling capability (user-specified vegetation categories and sub-grid soil characteristics)

  13. Aggregated: one patch containing dominant or aggregated surface parameters Mosaic: multiple patches, each containing individual surface parameters Global Climate Models (GCMs) and Regional Climate Models (RCMs) have a limited resolution. • Each grid cell contains a variety of surface types

  14. Effect of CLASS v3.0 on surface temperature simulation Test grid cell selected over Thompson, MB; CLASS v2.7 and v3.0 run offline with saved RCM met forcing. Results show that v3.0 tends to eliminate cold night-time bias, largely owing to new canopy turbulent transfer and stomatal conductance formulations.

  15. SWE, density and depth observed at BERMS – OJP for winter 2002-2003 and modelled using CLASS versions 2.7 and 3.0 SWE is modelled well using both CLASS 2.7 and CLASS 3.0. Snow density is overestimated by CLASS 2.7, whereas CLASS 3.0 incorporates improved algorithms, and performance is improved. As a result of its overestimation of snow density, CLASS 2.7 under- estimates snow depth, while CLASS 3.0 performs better. Testing continues at BERMS sites and in the Mackenzie Basin.

  16. North-central Manitoba • a 1200 km² region of boreal forest • in the BOREAS Northern Study Area • known as the modelling sub-area Mosaic study area Four tower flux sites • Old Jack Pine (OJP) • Old Black Spruce (OBS) • Fen • Young Jack Pine (YJP) • observed surface fluxes and • meteorological variables • detailed surface characterization

  17. OJP YJP OBS FEN 13.5 3 12 0.5 Canopy height (m): Leaf area index: 1.9 1.2 4.6 1.5 165 200 270 130 RCMIN (s·m-1): Sand Clay Fibric peat Hemic peat Sapric peat Site properties at each of the four flux tower sites

  18. With an organic soil layer or a • composite soil layer at the • surface, QE,soil is overestimated. • With a sand soil column, • QE,soil is underestimated • due to rapid drainage. Soil evaporation • The 4-patch and 2-patch • mosaic model runs have • almost identical behaviour. • We were able to tune the • algorithm for soil evaporation • so that the composite soil • behaved similarly to the mosaic. QE,soil (W·m-2) • This is not meant as a solution • to soil evaporation, but merely • to minimize one source of error • while examining modelled QE. C.S.T. (hours)

  19. Thompson test grid cell: Effect of including mosaic tiles. (46% needleleaf forest, 31% deciduous forest, 20% short vegetation.) Aggregated run: bulk canopy formulation, single soil type. Jack pine and fen: vegetation and soil parameters obtained at BOREAS NSA.

  20. http://www.palmod.uni-bremen.de/~mprange/holocene.pdf

  21. WATCLASS Model

  22. Group Response Unit - to deal with basin heterogeneity Physically Based Streamflow Routing Watflood Theory

  23. Lakes are currently neglected in RCM/CLASS (8% coverage of Mackenzie Basin) Surface temperature time series for Great Slave Lake: observed at two buoys, and modelled for a grid cell centred on the lake. Water temperatures are generally damped; sensible heat fluxes lower, latent heat fluxes higher than over land.

  24. Next steps • Implement CLASS v3.0 into the CRCM • Add a lake model as a CLASS mosaic tile option • Test optimal mosaic configurations for different ecosystems/landscapes

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