6/14/2016AOMIP Sea level Atlantic-to-Arctic: an examination of the altimeter record Gennady Chepurin and James Carton Dept. Atmospheric and Ocean Science University of Maryland ERS-2/Envisat tandem flight (from pictures kindly provided by ESA)

6/14/2016AOMIP years repeat time latitude Geosat ERS T/P ERS GFO Jason Envisat Jason Cryosat SSH Satellites AVISO gridded merged

6/14/2016AOMIP Similarity of tide gauge and satellite SSH Corr. = 0.72 Richter et al., 2012; Volkov & Pujol, 2012

6/14/2016AOMIP Interannual Variations in the Nordic and Barents Seas blue lines: satellite SSH anomalies near corresponding tide gauges; red lines: smoothed tide gauges data RMS Satellite

6/14/2016AOMIP SST as a proxy for Heat Content SST’– HC’ correlation (from SODA) SST’ and HC’ time series SST HC ABC Winter Summer Seasonality of SST/HC(300m) correlations

6/14/2016AOMIP SST-SSH correlations In the sub-arctic gyre interannual variations (upper left panel) in sea level are in good agreement with both temperature and salinity variations because deep winter time mixing here. In the Greenland and Norwegian seas salinity variations play an important role. In the Barents Sea a contribution of atmospheric forcing to the interannual sea level variations is high especially in its northern part. On seasonal time scale correlations between SST and SSH (upper right panel) are high everywhere where ocean is deeper than ~1000 meters (black contour line) and considerably lower in shallow waters of Barents, North, Baltic and Bering seas. Interannual Seasonal RMS SST RMS SSH

6/14/2016AOMIP Trend Left panel shows linear trend ( O C/yr) in SST; right panel shows linear trend (cm/yr) in SSH.

6/14/2016AOMIP SST and SSH interannual variations Greenland Sea Sub-Arctic gyre

6/14/2016AOMIP SST and SSH seasonal cycle

6/14/2016AOMIP Seasonal SSH

6/14/2016AOMIP Seasonal vertical propagation Deep WaterBarents Sea

6/14/2016AOMIP CRYOSAT - 2 Cryosat-2 – Envisat difference

6/14/2016AOMIP Summary Seasonal Tide gauge variations > satellite SSH variations, but phase agrees. Seasonal SSH phase lags deepwater SSH by 2-3 months in shallow Barents Sea and near the Norwegian coast due to vertical propagation of the seasonal signal in temperature and salinity in shallow water. Interannual Tide gauge variations may be > satellite SSH variations, but phase agrees. SSH variations are cm in the sub-arctic gyre and Norwegian Sea, ~2.5 cm in the Barents and Greenland Seas. Different driving mechanisms sub-arctic gyre interannual SSH, SST, temperature and salinity variations are driven by changes in deep winter time mixing (and thus are in phase). Barents Sea significant wind-driven mass changes, especially in its northern part. Greenland and Norwegian Seas: salinity variations important. Trends Everywhere in the Nordic Seas SSH increased during The highest level rise is about 7 mm/yr (not accounting for GIA) and it appears in the sub-arctic gyre near the south-east coast of Greenland. Norwegian Sea the maximum trend in sea level is ~5 mm/yr, and in the Baltic Sea it changes from ~2.5 mm/yr on south to practically zero on north.

6/14/2016AOMIP Thank you

6/14/2016AOMIP SST and HC(300m) correlations Table 1. Cross-correlations Labrador SeaNorwegian SeaBarents Sea SSTHCNAOSSTHCNAOSSTHCNAO SST HC NAO Table 2. Seasonal SST/HC(300m) correlations Labrador SeaNorwegian SeaBarents Sea Winter Summer