Ninth International Conference on Permafrost ... - IARC Research

A Permafrost Model Incorporating Dynamic Variable Soil Depth and PropertiesRichard CoppellSchool of Geography, University of Leeds, Leeds, UKMet Office – Hadley Centre for Climate Prediction and Research, Exeter, UKSergey VenevskySchool of Geography, University of Leeds, Leeds, UKMet Office – Hadley Centre for Climate Prediction and Research, Exeter, UKIntroductionRecent dynamic global vegetation models, for example,LPG, SEVER (Sitch et al. 2003, Venevsky & Maksyutov2007), and land surface schemes, for example, IMOGEN,MOSES (Cox et al. 1999), have deficiencies in theirrepresentations of thermal and hydrological dynamics inthe permafrost zone. These deficiencies are related to thefollowing:(a) Inadequate representation of thaw/freeze processes(absence of frozen soil water fraction). This relates todiffering thermal conduction regimes between frozen (highconduction) and unfrozen (lower conduction) surface layersthat experience thawing and freezing, particularly seasonally(see French 2007).(b) Absence of the upper soil organic layer (moss/lichen). Distinctions may be made between thermal andhydrological properties of moss-dominated and lichendominatedsoils (Beringer et al. 2001), also modified by theinfluence of sedges (Usowicza et al. 2006).(c) Inadequate parameterisation of soil properties. Thenumber of types of soils represented within models may beexpanded to test if this is also a sensitive parameter.MethodsPermafrost data (Brown 1998, <strong>International</strong> PermafrostAssociation Standing Committee on Data Information andCommunication [comp.] 1998, 2003) is being comparedwith representations in SEVER, considering active layerdepth, seasonal variation, time precision, temperatureprofile, soil moisture profile, and physical and biological soilconstituents.Peatland soil profiles and vegetation cover develop overperiods of thousands of years, and a MATLAB modelreproducing this based on Frolking et al. (2001) is also beingassessed.This will provide the opportunity to create a dynamic soiland vegetation representation within SEVER in place ofmore static representations of peatland and soil types.AcknowledgmentsRichard Coppell is in receipt of UK NERC scholarship NE/F008341/1 with CASE funding from the Hadley Centre.ReferencesBeringer, J., Lynch, A.H., Chapin, F.S., Mack, M. & Bonan,G.B. 2001. The representation of Arctic soils in theland surface model: The importance of mosses. J.Climate 14(15): 3324-3335.Brown, J. 1998. Circumpolar Active-Layer Monitoring(CALM) Program: Description and data. In: M.Parsons & T. Zhang (eds.), Circumpolar Active-Layer Permafrost System, version 2.0. <strong>International</strong>Permafrost Association Standing Committee onData Information and Communication. Boulder,CO: National Snow and Ice Data Center/World DataCenter for Glaciology.Cox, P.M., Betts, R.A., Bunton, C.B., Essery, R.L.H.,Rowntree, P.R. & Smith, J. 1999. The impact ofnew land surface physics on the GCM simulation ofclimate and climate sensitivity. Climate Dynamics15(3): 183-203.French, H.M. 2007. The Periglacial Environment. Chichester,UK: Wiley, 478 pp.Frolking, S., Roulet, N.T., Moore, T.R., Richard, P.J.H.,Lavoie, M. & Muller, S.D. 2001. Modeling northernpeatland decomposition and peat accumulation.Ecosystems 4(5): 479-498.<strong>International</strong> Permafrost Association Standing Committeeon Data Information and Communication (comp.).1998. Circumpolar Active-Layer Permafrost System,Version 1.0. Edited by J. Branson, J. Brown & M.O.Leibman. Boulder, CO: National Snow and Ice DataCenter/World Data Center for Glaciology. CD-ROM.<strong>International</strong> Permafrost Association Standing Committeeon Data Information and Communication (comp.).2003. Circumpolar Active-Layer Permafrost System,Version 2.0. Edited by M. Parsons & T. Zhang.Boulder, CO: National Snow and Ice Data Center/World Data Center for Glaciology. CD-ROM.MacDonald, G.M., Beilman, D.W., Kremenetski, K.V.,Sheng, Y., Smith, L.C. & Velichko, A.A. 2006.Rapid early development of circumarctic peatlandsand atmospheric CH 4and CO 2Variations. Science314(5797): 285-288.Sitch, S., Smith, B., Prentice, I.C., Arneth, A., Bondeau, A.,Cramer, W., Kaplan, J.O., Levis, S., Lucht, W., Sykes,M.T., Thonicke, K. & Venevsky, S. 2003. Evaluationof ecosystem dynamics, plant geography and terrestrialcarbon cycling in the LPJ dynamic global vegetationmode. Global Change Biology 9: 161-185.51