Outline Background, climatology & variability Role of snow in the global climate system Indicators of climate change Future projections & implications.
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Presentation on theme: "Outline Background, climatology & variability Role of snow in the global climate system Indicators of climate change Future projections & implications."— Presentation transcript:
Outline Background, climatology & variability Role of snow in the global climate system Indicators of climate change Future projections & implications of global change
Distinct properties of snow High albedo (α = 0.45 to 0.95) Low thermal conductivity High emissivity (ε = 0.82 to 0.99) Translucent Limited by 0 o C (low energy status) Reservoir for water Porous Mobile surface Varies greatly in space & time
Surface radiation budget over snow Q * = net radiation K↓ = incoming shortwave radiation L↓ = incoming longwave radiation L↑ = σT 4 = outgoing longwave radiation (maximum of 316 W m -2 ) Q * = K ↓ (1- α) + L ↓ + σT 4
Snow and global change science Stephen Déry, ENSC 425/625 - 7 November 2006
Surface energy budget over snow Q * = net energy Q H = sensible heat flux Q E = latent heat flux (sublimation) = L s E Q G = ground heat flux Q M = snowmelt ΔQ S = change in heat storage Q * = Q H + Q E + Q G + Q M + ΔQ S
Hydrological Cycle Surface water budget: S = P – E – R
20 th Century Climatology Observed GFDL Ref: Masuda
Annual cycle of daily discharge in Skeena River (1955-2004) freshet
Variation of peak discharge with latitude for 42 Hudson Bay rivers Source: Déry et al. (2005), J. Climate.
Contribution of snow to river runoff Source: Barnett et al. (2005).
Teleconnections Definition: Atmospheric interactions between widely separated regions that have been identified through statistical correlations (in space and time). For example, the El Niño teleconnection with the Southwest United States involves large-scale changes in climatic conditions that are linked to increased winter rainfall.
Implications of global change Increase in planetary albedo (positive feedback on global warming) Decreasing water resources, including soil moisture Longer growing season Impacts on recreational activities Ecological implications
Online resources: Canadian Cryospheric Information Network: http://www.ccin.ca/ http://www.ccin.ca/ National Snow and Ice Data Center: http://nsidc.org/http://nsidc.org/ National Operational Hydrologic Remote Sensing Center: http://www.nohrsc.nws.gov/http://www.nohrsc.nws.gov/ BC Ministry of Environment: http://www.gov.bc.ca/env/ http://www.gov.bc.ca/env/ Rutgers Global Snow Lab: http://climate.rutgers.edu/snowcover/ http://climate.rutgers.edu/snowcover/