HR: 16:40h
AN: GC14A-03 INVITED    [Abstracts]
TI: A Spatially-Resolved Model of the Global Ocean Hydrate Reservoir
AU: * Archer, D
EM: d-archer@uchicago.edu
AF: University of Chicago, 5734 S. Ellis, Chicago, IL 60637, United States
AU: Buffett, B
EM: buffett@geosci.uchicago.edu
AF: University of Chicago, 5734 S. Ellis, Chicago, IL 60637, United States
AU: Brovkin, V
EM: victor@pik-potsdam.de
AF: Potsdam Institute for Climate Impact Research, P.O.Box 601203, Potsdam, 14412, Germany
AB: We have developed the first mechanistic model of the geographic distribution of the oceanic methane hydrate reservoir. In our previously published study (Buffett and Archer, EPSL 227: 185-199, 2004), we accounted for heterogeneity by binning the sea floor according to water depth, temperature, and oxygen concentration. Here we recompose the map of the global sea floor to examine the distribution of hydrate regionally, and to predict the impact of anthropogenic ocean warming on hydrate stability. We pay particular attention to the volume fraction of bubbles upon melting at the base of the stability zone, motivated by the idea that methane escape to the ocean depends on the bubble fraction exceeding a critical interconnected value. Our model finds the Arctic to be special in this regard, producing a greater bubble volume upon melting than the global average, because the cold water column supports hydrate stability at lower pressure than elsewhere. The Arctic is also special because warming can reach these shallow depths more quickly than it will reach the deeper depths in the rest of the world, and because of the polar amplification of warming. In spite of the Arctic hydrate sensitivity, however, experiments with the hydrate representation within the CLIMBER intermediate complexity model of the atmosphere and ocean predict the methane release response of hydrates in the coming centuries to be small.
DE: 0466 Modeling
DE: 1009 Geochemical modeling (3610, 8410)
DE: 1030 Geochemical cycles (0330)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting