The Community Atmosphere Land Exchange (CABLE) model:

Transcription

1 The Community Atmosphere Land Exchange (CABLE) model: results from ACCESS1.3 and new simulations with CABLE Rachel Law CABLE coordinator 26 th September 2012

2 Acknowledgements Land surface modelling team: Ying-Ping Wang, Eva Kowalczyk, Lauren Stevens, Jhan Srbinovsky, Bernard Pak, Tilo Ziehn CABLE committee: Gab Abramowitz, Vanessa Haverd, Eva Kowalczyk, Jhan Srbinovsky CABLE technical support: Jhan Srbinovsky, Kai Lu, Claire Carouge, Mike Rezny ACCESS support: Martin Dix, Hailin Yan CABLE roadmap writing team: Mike Raupach, Gab Abramowitz, Andy Pitman, Vanessa Haverd, Ying-Ping Wang, Albert van Dijk, Luigi Renzullo, Imtiaz Dharssi The CABLE community. ~100 people from 33 institutions Australian Climate Change Science Program (ACCSP)

3 The CABLE land surface model Role of land surface models Provide boundary conditions at the land-air interface e.g. albedo, surface T, heat and moisture fluxes Partition rainfall into runoff and evaporation River runoff as an input to the oceans Update state variables which affect surface fluxes e.g. snow cover, soil moisture, soil T, veg. cover, Leaf Area Index CABLE includes Biophysical component o Surface radiation transfer (direct beam/ diffuse, visible, NIR and thermal, sunlit/ shaded leaves) o Canopy turbulence o Two-leaf canopy o Six soil and three snow layers Biogeochemical component Land use and land use change o Patch representation of surface heterogeneity o No vegetation competition and succession

4 CABLE components leaf root wood metabolic structural CWD deposition weathering fixation fertilizer microbial slow passive inorganic N labile P sorbed P Strongly sorbed P Occluded P N loss P loss Biophysics (original CABLE) Biogeochemistry (CASA-CNP) CABLE (current)

5 CABLE timeline 1990: First land surface model developed in CSIRO. Single soil type, constant roughness length, no explicit treatment of vegetation. 1994: Added vegetation 1995: Added 6 soil and 3 snow layers, and an empirical stomatal model 1997: Another model of Soil Canopy Atmosphere Model (SCAM) developed with an empirical photosynthesis model 1998: Two-leaf canopy model developed 2003: CSIRO Biosphere Model (CBM) developed 2006: CBM and SCAM combined to form CABLE version 1.0. Released, last update v1.4b in Sep : CASA-CNP a global biogeochemical model of C, N and P developed Main technical documentation in Kowalczyk et al., CMAR tech report, 2006; Wang et al., BG, 2010; Wang et al., JGR, 2011.

6 CABLE development since v1.4b Multi-processor offline Global offline CAWCR - Bureau of Meteorology Mk3L Land Information System WRF Mk3L ACCESS CCAM TAPM CABLE 1.4b (single-site & CCAM) UNSW CMAR-Canberra BIOS2, SLI Other university work What about version control?

7 CABLE in ACCESS CABLE v1.4b (last released update 09/08) UM changes Change number of vegetation types Change number of soil layers Keep parts of MOSES (e.g. sea-ice) Link UM and CABLE variables (pack/unpack) Allow for tiled soil and snow CABLE development Multiple vegetation types per grid-cell Code revision: canopy, screen temperature Simpler albedo for 3 hourly radiation Partitioning of runoff and glacier capping Surface energy and water balance CABLE v1.8 in ACCESS1.3

8 ACCESS land scheme configurations Canopy formulation MOSES in ACCESS1.0 one big leaf model canopy placed beside bare ground CABLE in ACCESS1.3 two leaf model (sunlit and shaded leaves) canopy placed above the ground Grid Tiles 9 surface types (5 vegetated) with 9 tiles used in each grid cell 13 surface types (10 vegetated) with up to 5 tiles used in each grid cell Soil 4 layers, no subsurface tiling 6 layers, subsurface tiling Snow 1 layer 3 layers Kowalczyk et al., The land surface model component of ACCESS: description and impact on the simulated surface climatology, submitted to AMOJ. Note: No carbon output submitted to CMIP5 from either version of ACCESS

9 Vegetation distribution MOSES CABLE Lakes & wetland Water % of grid-cell Bare ground & permanent ice % of grid-cell

10 Vegetation distribution MOSES CABLE Trees % of grid-cell Shrubs, grass, crops % of grid-cell

11 1850 vs 2005 vegetation distribution Crop distribution % of grid-cell 1850, used in coupled simulations 2005, used in atmosphere-only simulation

12 Seasonal biases (from ERA-Interim), ACCESS1.3 atmosphere-only Precipitation Screen-level temperature Regions with underestimated precipitation tend to show warm biases DJF Pattern of biases similar across ACCESS1.0 and ACCESS1.3 JJA NH land. 1.3 warmer than 1.0 for DJF, cooler than 1.0 for JJA. mm/day ºC

13 Surface albedo ACCESS1.0 ACCESS1.3 Generally lower albedo in 1.3 Canopy protrudes through snow layer Leaf optical properties not accounting for low snow-free soil albedo

14 Runoff: northern spring and summer ACCESS1.0 ACCESS1.3 Warmer winter/ spring temperatures in ACCESS1.3 lead to earlier snow-melt and runoff mm/day

15 Australian precipitation: DJF ACCESS1.0 ACCESS1.3 BoM Obs Atmosphere -only Coupled mm/day

16 Australian screen-level temperature ACCESS1.0 ACCESS1.3 ERA-Interim DJF Atmosphere only cases shown, coupled cases similar JJA ºC

17 Australian temperature: diurnal amplitude DJF JJA ACCESS1.0 ERA-Int ACCESS1.0 ERA-Int ACCESS1.3 BoM ACCESS1.3 BoM ºC

18 CABLE-2.0 Combines offline (global, regional, single-site) and ACCESS versions with common science code Cleaner code including interface to UM Inclusion of biogeochemistry (CASA-CNP) though not fully implemented Hydraulic redistribution (optional, default OFF) Soil water flux correction for energy balance Version control in Subversion repository hosted at NCI Trac page to facilitate community code development Release date: September 26, 2012 Multi-processor offline Mk3L ACCESS CCAM Global offline TAPM CAWCR - Bureau of Meteorology CABLE 1.4b (single-site & CCAM) Mk3L UNSW Land Informa System CMAR- BIOS2, Other universit work Soon!

19 CABLE trac page

20 CABLE-2.0 benchmarking

21 Offline benchmarks: single-sites workspace CABLE2.0_benchmark

22 Offline benchmarks: global , at 1º x 1º resolution with GSWP2 meteorological forcing Latent heat Gross Primary Productivity

23 ACCESS benchmark, atmosphere-only, 20 years Seasonal screen level temperature bias ACCESS1.3 CABLE2.0 CABLE2.0 revised optical properties Dec/Jan/Feb Jun/Jul/Aug

24 June-August surface albedo ACCESS1.3 CABLE2.0 CABLE2.0 revised optical properties

25 Rachel Law CABLE coordinator CABLE workshop, Oct , UNSW Phone: CABLE trac page: CABLE list: Thank you Thank you