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exchange (diminished by low insolation due to heavy cloudiness behind a warm 

 front). 



In the NE and N part this advection turns to cold advection from the 

 NE. Slight upwelling can be expected in the center of a cyclone due to 

 divergence in the surface layers . 



Subsequent changes in the atmosphere . In the W and SW part of the 

 cyclone, the cool advection counteracts the normally large sea-air exchange 

 and warming of the air, which results in further SE movement of the cold front. 



In the S and SE part the warm advection would extend the area of heat loss 

 toward the NE, accompanied by a pressure fall in the same direction. It is 

 thus apparent that the advective and local changes cause a kind of twisting 

 movement around a cyclone giving a force in the NE direction. The model of 

 occluded cyclones together with the description above also gives partial 

 explanation why occluded cyclones tend to move more to the left. The above 

 model also explains partly the tendency of cyclone centers (.and the W parts 

 of them) to locate over areas with positive sea surface temperature anomalies. 



This description of the feedback model should not be considered as a 

 final one, but rather as a framework, subject to further refinement. The 

 observed pressure tendency anomalies, empirically related to sea-air exchange, 

 remain unexplained in detail in these models. 



The above described model should be thought of as entirely auxiliary to 

 existing operational models of atmospheric behavior, providing an additional 

 "correctional" factor only. 



Partial verification of the above described feedback model has been 

 sought and indeed found. The effects on the ocean are demonstrated in 

 Figures lU to l6. Figures 1^ and 15 show surface pressure distribution and 

 the positions of sea surface isotherms on 10 and 13 December 196^4-. Figure l6 

 shows the sea surface temperature changes at four selected grid points in this 

 area and period, taken from Fleet Numerical Weather Facility's synoptic 

 analysis of sea surface temperature ( Wolff, 196^).- Positions of these grid 

 points are indicated on Figure ik. An examination of Figures 13 to 15 indicates 

 that the observed short-term sea surface temperature changes are partly 

 advectional and correspond to the changes described and expected in the above 

 simplified feedback model. The partially advective nature of the short-terra 

 sea surface temperature changes is furthermore substantiated by the synoptic 

 analyses of surface currents (Hubert, 196i|) . Furthermore the change of sea 

 surface isotherms between 12 and Ik December 196U (Figure 17) also indicates 

 that the sea surface temperature change patterns are large in scale and 

 correspond to expected advectional patterns, as shown by a comparison to surface 

 pressure analysis charts for this period. 



The preliminary verification tests of the atmospheric part of the feed- 

 back model, utilizing the short-term sea surface temperature anomalies, was 

 done subjectively for a number of forecasting periods. The results indicated 



