SECT. 2] 



LARflK-SOALE INTERACTIONS 



105 



physically valuable occasions when the energy balance method may be used in 

 average ocean-atmosphere budget studies over a month or more. Selected 

 examples will be described in the following sections of this chapter. The test of 

 the usefulness of the approach is whether a consistent quantitative picture can 

 be constructed, supported by a sufficient number of independent determina- 

 tions, whose major features and conclusions do not lie within the margin of 

 error of the computations. In practice, the equations may often be used to 

 obtain the sum of heat-energy exchange, Qs plus Qe, which then may be sepa- 

 rated if either one alone or the ratio between them is determinable. Jacobs, in 



Mean fractional cloudiness n — »- 

 Fig. 5. Graph illustrating approximately linear decrease of radiation balance, R, with 

 mean fractional cloudiness, n. R is the difference between Q + q (equation 4) and Qij 

 (equation 5). Constants A and B found graphically by fitting closest straight line to 

 R curve. Constants in equations (4) and (5) taken from tables in Budyko (1956) for 

 latitude 20\ February. Compviting Qg from R and equation (1), ignoring S and Qio 

 and assuming Qs = ~ioQej we find (in kg cal/cm^ month) Qe is 11.1, 7.5 and 3.3 for 

 cloudiness of 0, 40 and 100%, respectively. Compare with Table XI, line 11 and 

 Fig. 29. 



his classical studies, used the work of Bowen (1926) to assess their ratio r, which 

 may be shown to depend linearly upon the ratio of the respective air-sea 

 property differences as follows 



"" Qe L 



Tc 



qo-qa 



where Cp is the specific heat of air at constant pressure, L is the latent heat of 

 condensation. To is the sea-surface temperature and Ta is the air temperature at 

 about 6 m height, both in degrees Centigrade, go is the saturation specific 

 humidity at the sea-surface temperature, and qa is the actual atmospheric 

 specific humidity at 6 m, both in grams per gram. The origin and range of 

 validity of (7) will be discussed below in connection with the transfer formulas. 



