|
A Dynamic Global Vegetation Model (DGVM) is a computer program that simulates shifts in potential vegetation and its associated biogeochemical and hydrological cycles as a response to shifts in climate. DGVMs use time series of climate data and, given constraints of latitude, topography, and soil characteristics, simulate monthly or daily dynamics of ecosystem processes. DGVMs are used most often to simulate the effects of future climate change on natural vegetation and its carbon and water cycles. DGVMs generally combine biogeochemistry, biogeography, and disturbance submodels. Disturbance is often limited to wildfires, but in principle could include any of: forest/land management decisions, windthrow, insect damage, ozone damage etc. DGVMs usually "spin up" their simulations from bare ground to "equilibrium" vegetation to establish realistic initial values for their various "pools": carbon and nitrogen in live and dead vegetation, soil organic matter, etc. corresponding to a documented historical vegetation cover. DGVMs are usually run in a spatially distributed mode, with simulations carried out for thousands of "cells", geographic points which are assumed to have homogeneous conditions within each cell. Simulations are carried out across a range of spatial scales, from global to landscape. Cells are usually arranged as lattice points; the distance between adjacent lattice points may be as coarse as a few degrees of latitude or longitude, or as fine as 30 arc-seconds. Simulations of the conterminous United States in the first DGVM comparison exercise (LPJ and MC1) called the VEMAP〔VEMAP Members. 1995. Vegetation/ecosystem modeling and analysis project: comparing biogeography and biogeochemistry models in a continental-scale study of terrestrial ecosystem responses to climate change and CO2 doubling. Global Biogeochemical Cycles. 9(4):407-437〕 project in the 1990s used a lattice grain of one-half degree. Global simulations by the PIK group and collaborators 〔Cramer, W., A. Bondeau, F.I. Woodward, I.C. Prentice, R. Betts, V. Brovkin, P.M. Cox, V. Fischer, J.A. Foley, A.D. Friend, C. Kucharik, M.R. Lomas, N. Ramankutty, S. Sitch, B. Smith, A. White, and C. Young-Molling. 2001. Global response of terrestrial ecosystem structure and function to CO2 and climate change: results from six dynamic global vegetation models. Global Change Biology 7:357-373〕 using 6 different DGVMs (HYBRID, IBIS, LPJ, SDGVM, TRIFFID, and VECODE) used the same resolution as the general circulation model (GCM) that provided the climate data, 3.75 deg longitude x 2.5 deg latitude, a total of 1631 land grid cells. Sometimes lattice distances are specified in kilometers rather than angular measure, especially for finer grains, so a project like VEMAP 〔http://www.cgd.ucar.edu/vemap/〕 is often referred to as 50 km grain. Several DGVMs appeared in the middle 1990s. The first was apparently IBIS (Foley et al., 1996), VECODE (Brovkin et al., 1997), followed by several others described below: Several DGVMs have been developed by various research groups around the world: * LPJ〔Sitch S, Smith B, Prentice IC, Arneth A, Bondeau A, Cramer W, Kaplan JO, Levis S, Lucht W, Sykes MT, Thonicke K, Venevsky S 2003. Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the LPJ Dynamic Global Vegetation Model. ''Global Change Biology'' 9, 161-185.〕〔http://www.pik-potsdam.de/research/cooperations/lpjweb/〕 - Germany, Sweden * IBIS - Integrated Biosphere Simulator 〔Foley, J. A., I. C. Prentice, N. Ramankutty, S. Levis, D. Pollard, S. Sitch, and A. Haxeltine. 1996. An integrated biosphere model of land surface processes, terrestrial carbon balance, and vegetation dynamics. Global Biogeochemical Cycles 10(4), 603-628.〕〔Kucharik, C. J., J. A. Foley, C. Delire, V. A. Fisher, M. T. Coe, J. D. Lenters, C. Young-Molling, N. Ramankutty, J. M. Norman, and S. T. Gower. 2000. Testing the performance of a Dynamic Global Ecosystem Model: Water balance, carbon balance, and vegetation structure. Global Biogeochemical Cycles 14(3), 795-825.〕〔Foley, J. A., C. J. Kucharik, and D. Polzin. 2005. Integrated Biosphere Simulator Model (IBIS), Version 2.5. Model product. Available on-line () from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. .〕 - U.S. * MC1〔Bachelet D, Lenihan JM, Daly C, Neilson RP, Ojima DS, Parton WJ (2001). MC1: a dynamic vegetation model for estimating the distribution of vegetation and associated carbon, nutrients, and water -- technical documentation. Version 1.0. General Technical Report PNW-GTR-508. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station.〕〔Daly, C., D. Bachelet, J.M. Lenihan, R.P. Neilson, W. Parton, and D. Ojima, Dynamic simulation of tree-grass interactions for global change studies, Ecological Applications, 10, 449-469, 2000.〕〔(MC1 website )〕 - U.S. * HYBRID〔Friend AD, Stevens AK, Knox RG, Cannell MGR (1995) A process-based terrestrial biosphere model of ecosystem dynamics (Hybrid v3.0). ''Ecological Modelling'', 95, 249-287.〕 - U.K. * SDGVM〔Woodward FI, Lomas MR, Betts RA (1998) Vegetation-climate feedbacks in a greenhouse world. ''Philos. Trans. R. soc. London, Ser. B'', 353, 29-38〕 - U.K. * SEIB-DGVM〔http://seib-dgvm.com/〕 - Japan * TRIFFID〔http://www.metoffice.gov.uk/research/hadleycentre/models/carbon_cycle/models_terrest.html〕 - U.K. * VECODE〔Brovkin V, Ganopolski A, Svirezhev Y (1997) A continuous climate-vegetation classification for use in climate-biosphere studies. ''Ecological Modelling'', 101, 251-261.〕 - Germany * CLM-DVGM〔Levis SG, Bonan B, Vertenstein M, Oleson KW (2004) ''The Community Land Model's Dynamic Global Vegetation Model (CLM-DGVM): Technical Description and User's Guide, NCAR Tech. Note TN-459+IA'', 50 pp, National Center for Atmospheric Research, Boulder, Colorado.〕 - U.S. * Ecosystem Demography (ED,〔Moorcroft, P. R., G. C. Hurtt, and Stephen W. Pacala. "A method for scaling vegetation dynamics: the ecosystem demography model (ED)." Ecological monographs 71.4 (2001): 557-586.〕 ED2〔Medvigy, D., et al. "Mechanistic scaling of ecosystem function and dynamics in space and time: Ecosystem Demography model version 2." Journal of Geophysical Research: Biogeosciences (2005–2012) 114.G1 (2009).〕) The next generation of models - earth system models (ex. CCSM,〔http://www.ccsm.ucar.edu/〕 ORCHIDEE,〔http://orchidee.ipsl.jussieu.fr/〕 JULES,〔http://www.jchmr.org/jules〕 CTEM〔http://www.cccma.bc.ec.gc.ca/ctem/〕 ) - now includes the important feedbacks from the biosphere to the atmosphere so that vegetation shifts and changes in the carbon and hydrological cycles affect the climate. DGVMs commonly simulate a variety of plant and soil physiological processes. The processes simulated by various DGVMs are summarized in the table below. Abbreviations are: NPP, net primary production; PFT, plant functional type; SAW, soil available water; LAI, leaf area index; I, solar radiation; T, air temperature; Wr, root zone water supply; PET, potential evapotranspiration; vegc, total live vegetation carbon. References: 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dynamic global vegetation model」の詳細全文を読む スポンサード リンク
|