Weather regime transitions and the interannual variability of the North Atlantic Oscillation. Part II: Dynamical processes
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Figure 5. Time sequences of composited geopotential height anomalies at 300 hPa for NAO  to NAO transition events within P1 and for NAO to NAO transition events within P2, in which the dashed (solid) line denotes the negative (positive) value: (a) NAOto NAOtransition (the contour interval (CI) is 40 gpm) and (b) NAO to NAO transition (CI=40 gpm). The dark (light) shading indicates positive (negative) value regions that exceed the 95% confidence level for a two-sided student’s t-test.
 
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Figure 6. Time sequences of the amplitude of each wave component for wavenumber 1-3 in the composited geopotential height anomalies for transition events, in which Lag 0 denotes the maximum amplitude of the NAO anomaly before the transition: (a) NAO to NAO transition in P1 and (b) NAO to NAO transition in P2.
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Figure 7. Hovmöller diagrams of the composite geopotential height anomaly averaged from  to  as a function of longitude and time (Lag days): (a) NAO to NAO transition and (b) NAO to NAO transition. The thick bar denotes the propagation of the maximum.
 
Figure 8, Time variation of the zonal position of the maximum amplitude of the large-scale high-latitude negative (positive) anomaly over the European continent and its downstream region for the composite NAO anomaly from the NAO to NAO (NAO to NAO) transition, in which “-30” and “30” denote “ ” and “ ” respectively, and the solid (dashed) curve represents wavenumber 1 (wavenumber 2) : (a) NAO to NAO transition events and (b) NAO to NAO transition events.
 
Figure 9, As Fig.8, except for the composite NAO anomaly for NAO events without transition: (a) NAO and (b) NAO.
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Figure 10. Difference of the composited barotropic zonal wind averaged from Lag-15 to Lag-10 between the transition and non-transition events within P1 (a) and P2 (b), in which the shading denotes the region above the 80% confidence level for a two- sided Student’s t-test. 
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Figure 11. As Fig.10, except for the eddy kinetic energy at 300-hPa. Directory: ~sbf1 -> papers papers -> Weather regime transitions and the interannual variability of the North Atlantic Oscillation. Part I: a likely connection Download 121.91 Kb. Share with your friends:
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