HR: 17:00h
AN: C34A-05    [Abstracts]
TI: The Impact of Heterogeneous Snow Cover On Simulated Northern Hemisphere Carbon, Water and Heat Exchange
AU: Wiltshire, A J
EM: a.j.wiltshire@durham.ac.uk
AF: Climate and Land Surface Systems Interaction Centre, School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE, United Kingdom
AU: Sitch, S
EM: stephen.sitch@metoffice.gov.uk
AF: MetOffice Hadley Centre, Fitzroy Road, Exeter, EX1 3PB, United Kingdom
AU: Bennie, J J
EM: j.j.bennie@durham.ac.uk
AF: Climate and Land Surface Systems Interaction Centre, School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE, United Kingdom
AU: Essery, R L
EM: r.l.essery@edinburgh.ac.uk
AF: School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3JW, United Kingdom
AU: Huntley, B
EM: brian.huntley@durham.ac.uk
AF: Climate and Land Surface Systems Interaction Centre, School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE, United Kingdom
AU: Harding, R J
EM: rjh@ceh.ac.uk
AF: Climate and Land Surface Systems Interaction Centre, Centre for Ecology and Hydrology, Wallingford, OX 10 8BB, United Kingdom
AU: * Baxter, R
EM: robert.baxter@durham.ac.uk
AF: Climate and Land Surface Systems Interaction Centre, School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE, United Kingdom
AB: We present the impact of a new sub-grid heterogeneous snow scheme in the Joint UK Land Environment Simulator (JULES). Snow tends to accumulate on vegetation and in topographic hollows. These snow drifts melt out later, extending the snow lie period and reducing the available growing season for buried plants. The scheme represents the interaction between vegetation and topography on the landscape scale, and the effect of partial burying of vegetation on gross primary productivity. We present the results from global 1 degree simulations from 1982-1995 for the new scheme and base line simulations. Results suggest that the representation of northern hemisphere snow cover play an important role in the seasonal carbon, water and heat cycles. The improved scheme delays the onset of snow-free conditions by representing the formation of deep drifts which take longer to melt out. In turn, this decreases the volume of surface runoff resulting from the rate of snow melt exceeding the surface infiltration capacity. Snow is maintained longer into the growing season which delays the seasonal drawdown in atmospheric carbon dioxide. Results suggest that this process may improve the representation of biogeochemical cycling and biogeophysics in the seasonally frozen high-latitudes. This represents a step towards improved coupled GCM simulations in these regions.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0416 Biogeophysics
DE: 0736 Snow (1827, 1863)
DE: 1814 Energy budgets
DE: 1876 Water budgets
SC: Cryosphere [C]
MN: 2007 Fall Meeting