Connectivity between Eurasian snow extent and Canadian snow mass and

river discharge

S. J. Déry, J. Sheffield, and E. F. Wood, Princeton

Decreasing river discharge in northern Canada, 1964-2003

Source: Déry and Wood (2005), GRL.

Teleconnection between the AO and Hudson Bay river discharge

Source: Déry and Wood (2004), GRL.

Datasets• Satellite-based measurements of mean

monthly Eurasian snow extent from NOAA, 1973-2003.

• CMC mean monthly snow mass over North America, 1979-1997 (Brown et al. 2003).

• Canadian river discharge from HYDAT, 1973-2003 (Déry et al. 2005; Déry and Wood 2005).

• Global meteorological fields from ERA-40.

Methods• Study period: 1973-2003.

• Normalized time series of monthly Eurasian snow extent, annual Canadian maximum snow mass, and monthly river discharge.

• Focus on Churchill River (Labrador) and Chesterfield Inlet (Nunavut) Basins.

• Correlations are then performed, with time lags imposed,and are considered statistically-significant when p < 0.05.

Monthly Eurasian normalized snow extent anomalies

Churchill River normalized annual snow & river discharge anomalies

Chesterfield Inlet normalized annual snow & monthly discharge anomalies

Correlation coefficient between

monthly normalized

Eurasian snow extent anomalies

and Canadian annual maximum

monthly snow mass anomalies

the following year, 1980-1997

Correlation coefficient between monthly Eurasian snow extent anomalies &

Canadian snow mass & river discharge anomalies the next year

Correlation coefficient between annual Eurasian snow extent anomalies &

discharge anomalies the following year in 64 rivers of northern Canada

ERA-40 difference (1980-1989) in winter/spring a) SLP (hPa) and b) 500

hPa geopotential height (dam)

Difference (1980-1989) in winter/spring

maximum snow mass (kg

m-2) from Brown et al.

(2003)

Physical Mechanism for Pan-Arctic Climate Connectivity

• Soil moisture anomalies in Eurasia (Barnett et al. 1988, 1989)

• North Atlantic SST anomalies (Saunders et al. 2003)

• Polar wave flux activity (Gong et al. 2003)• Persistence of snow extent anomalies – AO

correlates more significantly to annual (not seasonal) Eurasian snow extent anomalies.

Autocorrelation of monthly Eurasian normalized snow extent anomalies,

1973-2003

Summary• Annual maximum snow mass and streamflow

in northern Quebec & Labrador is significantly correlated to Eurasian snow extent anomalies

• Persistence of the Eurasian snow extent anomalies during spring is critical to pan-Arctic connectivity.

• Thanks to: Land surface hydrology group at Princeton, Marc Stieglitz (Georgia Tech.), Ed McKenna, & Ross Brown (CMC).

Trends in Northern Hemisphere snow extent