Clara Deser, NCAR Symposium in Honor of Maurice Blackmon

Clara Deser, NCAR Symposium in Honor of Maurice Blackmon Mentor Extraordinaire CDC Postdoc Res. Sci NCAR Scientist 1997-

Clara DeserMarika HollandBette Otto-Bliesner CGD Women Scientists Hired by Maurice Blackmon

Blackmon and Bjerknes: Air-Sea Interaction in the North Atlantic Clara Deser, NCAR

Blackmon J.Bjerknes Synoptic Meteorology ENSO North Atlantic Air-Sea Interaction

Year-to-year variability Multi-decadal trends: Ocean forcing atmosphere? Composite SLP, SST High (1904, 1913, 1920) minus Low (1902, 1909, 1915) minus “Atlantic Air-Sea Interaction” Jacob Bjerknes, 1964, Adv. in Geophysics 82 pp

Year-to-year variability: Multi-decadal trends: Ocean forcing atmosphere? Composite SLP, SST High (1904, 1913, 1920) minus Low (1902, 1909, 1915) minus W C H L “Atlantic Air-Sea Interaction” Jacob Bjerknes, 1964, Adv. in Geophysics 82 pp

Year-to-year variability: Atmosphere forcing ocean Multi-decadal trends: Ocean forcing atmosphere? Composite SLP, SST High (1904, 1913, 1920) minus Low (1902, 1909, 1915) minus W C H L “Atlantic Air-Sea Interaction” Jacob Bjerknes, 1964, Adv. in Geophysics 82 pp

Year-to-year variability: Atmosphere forcing ocean Multi-decadal trends: Ocean forcing atmosphere? Composite SLP, SST High (1904, 1913, 1920) minus Low (1902, 1909, 1915) minus W C H L H L C W “Atlantic Air-Sea Interaction” Jacob Bjerknes, 1964, Adv. in Geophysics 82 pp

Year-to-year variability: Atmosphere forcing ocean Multi-decadal trends: Ocean forcing atmosphere? Composite SLP, SST High (1904, 1913, 1920) minus Low (1902, 1909, 1915) minus W C H L H L C W

Gulf Stream “Warming” (Bjerknes, 1964) +3 °C

Year-to-year variability: Atmosphere forcing ocean Multi-decadal trends: Ocean forcing atmosphere? Composite SLP, SST High (1904, 1913, 1920) minus Low (1902, 1909, 1915) minus W C H L H L C W “Atlantic Air-Sea Interaction” Jacob Bjerknes, 1964, Adv. in Geophysics 82 pp

North Atlantic Air-Sea Interaction Revisited “Surface Climate Variations over the North Atlantic Ocean during Winter: ” Deser and Blackmon (J. Climate 1993) “Interdecadal Variations in North Atlantic Sea Surface Temperature and Associated Atmospheric Conditions” Kushnir (J. Climate 1994) Comprehensive Ocean-Atmosphere Data Set (COADS) NOAA OGP “Atlantic Climate Change Program”

Percent of months with data COADS Data Coverage

Warm minus Cold Years 50-60N Year-to-year variability: Atmosphere forcing ocean W C H L H L C W Kushnir 1994 W W C H L

minus Multi-decadal trends: Ocean forcing atmosphere? W L

Deser and Blackmon (1993) Objective Analysis of Sea Surface Temperature Variability Sea Ice SST EOF 2 ( ) + -

Deser and Blackmon (1993) Objective Analysis of Sea Surface Temperature Variability Sea Ice SST EOF 2 ( ) C W Associated Surface Winds + -

Deser and Blackmon (1993) Objective Analysis of Sea Surface Temperature Variability Sea Ice SST EOF 2 ( ) C W Associated Surface Winds SST, Air T + -

Deser and Blackmon (1993) Objective Analysis of Sea Surface Temperature Variability Sea Ice SST EOF 2 ( ) C W Associated Surface Winds ICE SST, Air T ICE SST

Atmospheric Response to North Atlantic Sea Ice and Sea Surface Temperature Anomalies Recent Work

Atmospheric Response to North Atlantic Sea Ice and Sea Surface Temperature Anomalies Recent Work Shiling Peng with Ting, Whittaker, Hoerling, Alexander, Li NOAA Climate Diagnostics Center “The Transient Atmospheric Circulation Response to North Atlantic SST and Sea Ice Anomalies” (Deser, Tomas and Peng: J. Climate 2007)

Transient Atmospheric Response Imposed SST Anomaly Dec 1 Apr 30 SST climatology + anomaly SST climatology Initial Condition 1 Initial Condition 240 SST climatology SST climatology + anomaly Atmospheric GCM Experiments (NCAR CCM3) +6 °C

Geopotential Height Response Day 1 Day 2 Day 3 Day 4 Day 5 Positive Negative Contour interval = 10 m shading: 95% significance

Weekly Response

Weekly Response Baroclinic  Barotropic Amplification Local  Hemispheric

Spatial Correlations Between 1000mb and 300mb Geopotential Height Responses Transition at 4 weeks Baroclinc Barotropic

Geopotential Height Response Intrinsic Variability

Geopotential Height Response Forced by Diabatic Heating Transient eddy vorticity flux convergence

+ SST - SST Equilibrium Geopotential Height Response + SST

Clara Deser, NCAR Symposium in Honor of Maurice Blackmon