HadCM3M2 : Model documentation and description of experimental setup Version as of : 16 August 2005. Owner : Michel Crucifix. michel.crucifix@metoffice.gov.uk Model documentation ------------------- HadCM3M2: atmosphere: (2.5 x 3.75 x 19 levels on vertical); reference: V. D. Pope, M. L. Gallani, P. R. Rowntree, and R. A. Stratton. The impact of new physical parametrizations in the Hadley Centre climate model -- HadAM3. Clim. Dyn., 16:123-146, 2000. ocean: (1.25 x 1.25 x 20 levels on the vertical. B-GRID); sea-ice : thermodynamic - dynamic (0-layer) reference: C. Gordon, C. Cooper, C. A. Senior, H. Banks, J. M. Gregory, T. C. Johns, J. F. B. Mitchell, and R. A. Wood. The simulation of SST, sea ice extents and ocean heat transports in a version of the Hadley Centre coupled model without flux adjustments. Clim. Dyn., 16:147-168, 2000. land: surface scheme MOSES II : tiled scheme with 9 different possible surface types : broadleaved trees, needleleaved trees, C3 grass, C4 grass, shrubs, inland water, urban, bare soil, snow or ice. Soil model with thermal diffusion and Darcy law on 4 depth levels. No horizontal fluxes. Overflow water ran-off instantaneously to the ocean, location of water release provided by a lookup-table linking each land grid point to a location in the ocean. reference : R. L. H. Essery, M. J. Best, R. A. Betts, P. M. Cox, and C. M. Taylor. Explicit representation of subgrid heterogeneity in a GCM land- surface scheme. J. Hydrometeorol., 4(3):530-543, 2003. Note : Essery mentions a new boundary-layer scheme, which is not applied in HadCM3M2. Vegetation model : TRIFFID. Based on carbon balance and simple competion rules between 5 PFTS : needleleaved trees, broadleaved trees, C3 grass, C4 grass, shrubs. Temperature-driven phenology scheme for trees. Explicit water limitation for photosynthesis. Reference: P. M. Cox, R. A. Betts, C. D. Jones, S. A. Spall, and I. J. Totterdell. Modelling vegetation and the carbon cycle as interactive elements of the climate system. Technical Note 23, Hadley Centre, Met Office, 2001. Available from http://www.hadleycentre.gov.uk/research/hadleycentre/pubs/HCTN/HCTN_23.pdf Experimental Setup : -------------------- Present-day experiment : 0K OAGCM. ========= Initial conditions : HadCM3 control as in Johns et al. T. C. Johns, J. M. Gregory, W. J. Ingram, C. E. Johnson, A. Jones, J. A. Lowe, J. F. B. Mitchell, D. L. Roberts, D. M. H. Sexton, D. S. Stevenson, S. F. B. Tett, and M. J. Woodage. Anthropogenic climate change for 1860 to 2100 simulated with the HadCM3 model under updated emissions scenarios. Clim. Dyn., 20:583-612, doi 10.1007/s00382-002-0296-y, Apr 2003. Model modifications : (introduce MOSES II / porting on NEC computer) Boundary conditions and forcing. Ozone, land-sea mask, river-run off and topography unchanged. Total Solar Irradiance : As MOTIF guidelines. GHG : as MOTIF guidelines (applied after Spin-up-phase 1) Spin-up-phase 1 : 170 years Then correct bug in MOSES II and adjust GHG gases to MOTIF guidelines Spin-up phase 2 : 300 years Run for Climatological Means : 100 years Additional run for daily means : to be determined. Name of experiment on Met Office system : AEIKF. 0K OAVGCM. ========= as 0K OAGCM coupled with TRIFFID but: Spin-up-phase 1 : 130 years correct bug in MOSES II and adjust GHG gases to MOTIF guidelines Spin-up phase 2 : 300 years Run for Climatological Means : 70 years : to be continued Additional run for daily means : to be determined. Name of experiment on Met Office system : AEIKG. 21K OAGCM --------- Start from run documented in : C. D. Hewitt, R. J. Stouffer, A. J . Broccoli, J. F. B. Mitchell, and P. J. Valdes. The effect of ocean dynamics in a coupled GCM simulation of the last glacial maximum. Clim. Dyn., 20:203-218, doi 10.1007/s00382-002-0272-6, 2003. GHG gases: As MOTIF guidelines (nota : during Spin-up phase 1: scaling wrt to Johns et al.) Total Solar Irradiance : as in 0K experiments (MOTIF guidelines) Orography : Peltier ICE 5G 21 K - Peltier ICE 5G 0K + 0K OAGCM. Land-Sea Mask : Peltier ICE 5 G 21 K (above 0m considered as land) + a few punctual corrections for stability and through flow. Bathymetry : As in 0K experiments. Through flows : Bering Strait : Closed Indonesia : Passage between PNG and Java Trench : open (down to 2700 m) Passage from East China Sea to South China sea : open Passage from South Chine Sea to Banda Sea : open but 2-grid cell wide. Passage from South China Sea to Indian Ocean : closed. Passage between Florida and Cuba: open Tasmania : removed Passages open on both sides of Iceland. Inland Seas: Caspienne Sea and Black Seas : as today (need to double check). Run-off : changed during spin-up process. Final version uses : as control for South America, Africa and Indonesia Taken from Beta-2 release of HYDRA outputs (river_bas_21l_b2) for Eurasia and Ice sheets (this version was available on the MOTIF/PMIP websites for a limited time). Note : Error for Mediterranea : wter normally released to Mediterranea put West of Gibraltar strait. A sensitivity run will be produced to check consequences. Spin-up process: Phase 1 : 170 years with various adjustments for orography, bug-fix (MOSES II)Then : adjustment to actual MOTIF guidelines for GHG. Phase 2 : 380 years Production of climatological means : 100 years. 21K OAVGCM --------- as 21 K OAGCM, with interactive vegetation, but: Spin-up process: Phase 1 : 110 years with various adjustments for orography, bug-fix (MOSES II) and adjustmenet to actual MOTIF guidelines for GHG. Phase 2 : 380 years Production of climatological means : in progress.