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Key Considerations in Linking Permafrost, Ecosystems and Run-off. Readiness of Existing Models for Coupling Land-Atmosphere Water & Energy Cycles. William J. Gutowski, Jr. Dept. of Geological & Atmospheric Sciences Iowa State University. Complexity of Arctic terrain.
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Key Considerations in Linking Permafrost, Ecosystems and Run-off Readiness of Existing Models for Coupling Land-Atmosphere Water & Energy Cycles William J. Gutowski, Jr. Dept. of Geological & Atmospheric Sciences Iowa State University
Complexity of Arctic terrain A range of “permanent” land surface types (forest, tundra, wetlands, glaciers) 2. Seasonal variation: snow cover, freeze/thaw of soil and water bodies 3. Mix of hydrological landscapes (unorganized flow major rivers)
Atmosphere Are the fluxes (couplings) well modeled? (water availability, nutrients) Ecosystems Surface Water Permafrost (snow cover, albedo) (ponding, wet soil)
Issue: Resolution of Observations Borehole Locations
Borehole Locations Issue: Horizontal Resolution of Model ~ 0.5˚ grid Great Bear Lake Mackenzie River
Issue: Vertical Resolution of Model Active Layer Depth Over Permafrost (31 stations in Siberia; Frauenfeld et al., 2004)
Active Layer Depth Over Permafrost (31 stations in Siberia; Frauenfeld et al., 2004) Issue: Vertical Resolution of Model 10 cm 40 cm 100 cm NOAH LSM 200 cm (Chen and Dudhia, 2001)
1) Broadleaf-evergreen trees 2) Broadleaf-deciduous trees 3) Broadleaf and needleleaf trees 4) Needleleaf-evergreen trees 5) Needleleaf-deciduous trees (larch) 6) Broadleaf trees with groundcover 7) Groundcover only 8) Broadleaf shrubs with groundcover 9) Broadleaf shrubs with bare soil 10) Dwarf trees/shrubs with groundcover (tundra) 11) Bare soil 12) Cultivations 13) Wetland 14) Dry coastal complex 15) Water 16) Glacial Issue: Standard Landcover Types Sufficient Detail? Both specified as “12) Cultivations” Need “Data Rich” Approach
Further Challenges to Modeling • Movement of water and heat in frozen soil • Runoff sensitivity to presence/absence of permafrost • Annual cycle of river ice • Change in landscape structure (e.g., slumping with permafrost decline) • Change in wetlands (slow, disorganized flow) • Ecosystem evolution as permafrost and runoff change (dynamic vegetation modeling) • Permafrost evolution as ecosystems change