SECT. 2] 



SMALL-SCALE INTERACTIONS 



73 



measurements in the style of Figs. 12 and 13, with the corresponding treatment 

 of humidity measurements, will throw much light on the effects of the compli- 

 cating factors mentioned above. 



A tool which may prove to be of considerable value in investigating these 

 eff'ects is the use of the Taylor characteristic diagram, which is a plot of (poten- 

 tial) vapour pressure against (potential) temperature. Montgomery (1950) has 



0.2 



& • o 



-0.1 



-0 05 







f 0.05 



(a) Wind speed >5m/sec 



-0.8 -0.6 -0.4 -0.2 ^0.2 *0A ^0.6 +0.8 



(b) Winds <5m/sec 



Fig. 14. Observations of Fe (4 m) plotted against the bulk stability parameter, Bh^. 



Black symbols : grouped observations of Wiist and Montgomery. 

 Open symbols : individual observations, Port Phillip Bay, May, 1958. 



(a) Strong winds : •, O uq 5 to 7.5 m/sec 



A, -^ uq above 7.5 m/sec 



(b) Light winds: •, o uq below 3 m/sec 



A., ^ iiQ 3 to 5 m/sec 



given an elegant discussion of this form of plotting, which was introduced by 

 G. I. Taylor in 1917 for the study of water vapour in the atmosphere. Some 

 measurements plotted on the characteristic diagram are shown in Fig. 15. The 

 following is the principle on which the diagram is interpreted. When air, whose 

 characteristics are represented by some point on the diagram, flows over the 

 sea surface, represented by the point on the saturation curve at the appropriate 



