2Sk 



arrive at realistic monthly or seasonal average heat exchange values the 

 synoptic heat exchange must be computed with synoptic meteorological elements 

 and summed and averaged after these computations have been performed. 



EXAMPLES OF SYNOPTIC DISTRIBUTION OF HEAT EXCHANGE COMPONENTS 



Some examples of the distributions of heat exchange components are 

 shovm in Figures 1 to 7- The variations in insolation are largely determined 

 by the time of year, latitude and cloud cover (Figure l) . The effective back 

 radiation is also affected by cloudiness, the relative humidity and the sea 

 surface temperature (Figure 2). The transfer of latent heat and sensible heat 

 transfer are most directly connected to surface weather systems (Figures 3 

 and k) . These two components are summed together and the quantity called sea- 

 air exchange ( Q^ ) . Two consecutive days of Qg distribution over the North 

 Pacific are shown in Figures 6 and 7 together with the surface weather charts 

 and the total heat exchange (Q/ )• These figures indicate that the patterns 

 of Qa are large in scale, corresponding to surface weather patterns, and that 

 they change from day to day in the same manner as the weather patterns . In 

 lower latitudes, below 20° North, a number of smaller centers of Qa are 

 apparent. This is partly in agreement with the surface pressure distribution 

 as shown by synoptic analyses. Furthermore, there are some uncertainties 

 involved in the computations in this area, as the ship reports south of about 

 20°N, as well as north of about 55 N, are sparse. The higher values of Qg. 

 are usually found on the cold air side of cyclones . Low or negative values of 

 Qa are found, on the other hand, in the warm sectors of cyclones. Relatively 

 high Qa gradients can be found along the cold fronts . The relations of the 

 Qa fields to cyclones change slightly with the age of the cyclone itself. 



In some cases pronounced Qg^ contrasts have been observed in areas and 

 places where cyclogenesis would be expected and does, in fact, occur 1 to 2 

 days later. In the eastern parts of the ocean the Qa contrasts are much less 

 pronounced than in the western parts. The disappearance of Qa contrast within 

 a cyclone area usually precedes the dissipation of the cyclone, and might be 

 useful in forecasting the filling of a system. Physically, it can be explained 

 that the energy sources and sinks for the cyclones at the sea surface are cut 

 off due to the exchange processes at the surface. These tend to diminish the 

 gradients of properties between the sea surface and the lower layers of the 

 atmosphere and consequently to dissipate the cyclone because it has been cut 

 off from any new sources of energy. 



The relations between anticyclones and heat exchange patterns are less 

 distinct than in the case of cyclones. However, there is usually a higher 

 Qg^ in the eastern part of an anticyclone and lower Qa pattern in the western 

 part of it. Most of the well defined hl^ and/or low Qa patterns are related 

 both to the cyclone and the adjacent anticyclone (see further Figure 9)* 



