The method of prediction developed in this study can generally be used 

 anywhere in the ocean without previous information on the mixed layer and 

 thermocline; the only requirement is knowledge of the surface wind waves 

 and the stability index. 



If prediction of the thermocline depth is desired for an area where no 

 observations or predictions have been made or where none have been made for 

 the past 10 or more days, weather conditions in the area for at least the 

 past 20 days must be studied. If low or moderate wind sea has prevailed 

 for the last 10 days and a heavy storm has occurred within the past 12 to 

 15 days, it is reasonable to determine: (l) At what depth was the thermo- 

 cline established during the storm? and (2) Was the thermocline depth in- 

 creased by convergence after the storm? Answers to these questions provide 

 the initial value of mixed-layer thickness from which loss of thickness 

 due to decay must be subtracted to determine present mixed-layer thickness. 



If no great perturbations occurred during the previous few weeks and 

 if surface conditions remained approximately the same for a longer period 

 of time, the prediction can be based on the average existing surface con- 

 ditions. 



Examples of Prediction 



Example 1 - The wind field at the prediction point ( 52°48 ' N, 35°30* W) 

 is shown in Figure 33* Mean wind was about 2h knots from the northeast 



7 S* 



\rfi 



KwJTt I^A\5 



/ [V ^N P 









^^^m\ ^ 



Sfc 





-^ 6 °^-s ^ i/ / 



A / XJe^S^JK. 1 i 

 •ill iF vvy rtlff 



*)>*/* /X/\ ( '**>/' 



¥*y 





J^4-X^ 



-^W^^vaK 



















za4v^r*~yr\ / V 









FIGURE 33 NORMAL WIND FIELD AT A PREDICTION POINT (52° 48' N, 35° 30' W)- 

 I230Z, 12 JUNE 1951 



68 



