Outline • Background, climatology & variability • Role of snow in the global climate system • Contemporary observations of climate change • Cryospheric indicators of climate change • Future global & regional projections & implications of climate change
20th Century Climatology Observed GFDL Ref: Masuda
Current snow coverage 1 April 2013
Departure from average 1 April 2013
Mean annual maximum monthly snow water equivalent (mm) in Canada, 1980-1997(Brown et al. 2003)
Interannual variability Source: Karl et al. (1993).
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.
Correlation coefficient between annual Eurasian snow extent anomalies & discharge anomalies the following year in 64 rivers of northern Canada Source: Déry et al. (2005), JGR.
Warming air temperatures Climatic Research Unit, University of East Anglia, http://www.cru.uea.ac.uk/
20th century climate & trends Reference: Déry and Wood (2005)
Cryospheric indicators of global change • Snow depth, swe, density, albedo & temperature (heat content) • Duration of snow cover & growing season • Snowmelt/spring freshet date • Soil moisture
Snow depth Source: Curtis et al. (1998), Int. J. Climatology
Trend (%) in April 1st swe, 1950-1997 Source: Mote et al. (2005), BAMS
Albedo Source: Stone et al. (2002), JGR.
Snowmelt Date Source: Stone et al. (2002), JGR.
Trend in centre of volume in river discharge across western N. America Source: Stewart et al. (2005), J. Climate.
Expected indicators of climate change IPCC 3rd Assessment
Trends in Northern Hemisphere snow cover extent Source: Déry et al. (2006), JGR.
Projected change in seasonal snow cover frequency based on GFDL CM2 simulations (21st - 20th century) -0 Projected change in frequency
Projected change in seasonal snow water equivalent (swe) based on GFDL CM2 simulations (21st - 20th century) -1 Projected change in swe (mm)
Regional climate (baseline) • Source: PCIC (http://www.pcic.uvic.ca)