224 Evaporation from the Surface of the Sea and the Water Budget of the Earth 



atmosphere with Qi,, the loss by evaporation with Q^, and the loss by convection 

 (turbulent heat conduction) with Q^, then for a stationary state Qs ^ Qb-\- Qe+ Qh- 

 Introducing R = QJQe and E = QJL, where L is 585 cal/g, the latent heat of 

 evaporation of water, into the basic equation for the heat budget of the ocean (see 

 p. 89) then 



L(l + R) ' 



If the radiation terms Qs — Qb and R are known it is possible to calculate the evapora- 

 tion. Schmidt carried out this calculation using, however, R' == QeliQs — Qb) instead 

 of R, and determined R' from general considerations as about 0-70. This gives a mean 

 correction factor k for evaporation measurements on board ship, and he found k = 

 0-43 as the most probable value. For the extreme case ^^ = (disregarding all con- 

 vectional processes) Kleinschmidt (1921) found an upper value for k of 0-61. The 

 good agreement with the value of Wiist of 0-48 is remarkable. Angstrom (1920) 

 showed that Schmidt's estimate gave too large a value for R. From measurements and 

 energy considerations he concluded that the value of R is only 0-1, which means that 

 of the total gain in energy Q^ — Q^, only 10% will be given off to the atmosphere by 

 convection and approximately 90% used for evaporation. 



The method of Schmidt has been carried further by Mosby (1936), who attempted 

 in particular to remove the uncertainty in the determination of the incoming radiation 

 Qs by the use of an empirical formula (see p. 91). The values for Q^, thus obtained, 

 are given in Table 86. 



Table 86. Heat budget for the ocean. 



(According to Mosby (g cal cm"^ min~^)) 



The mean value between 70° N. and 70° S., taking into consideration the ocean area 

 of the separate zones, is estimated to 0-132 g cal cm~2 min~^ Since on average for the 

 entire ocean advective processes are assumed to be of no importance, this is the 

 average amount of heat available for evaporation and convection. However, Mosby 



