back and reflected radiation from the sea surface; to arrive 

 at the total effect the reading from the two instruments miist 

 be added. Pyrhellometer 3 measured the total incoming radiation 

 from both sun and sky. 



It was decided to attempt to forecast the changes in the 

 characteristics of the thermal structure from the morning of 

 20 April to the evening of 27 April. A representative BT, 



taken at 0500Z 20 April, was chosen 



TEMPERATURE (°F) 



6 2 63 64 65 66 67 68 69 70 as the Initial temperature distribution. 



2| 1 1 1 — rl 1 1 1 1 This BT trace is reproduced in figure 



[j. and plotted in meters for the sake of 

 convenience. 



It also was decided that the pre- 

 diction of the meteorological variables 

 themselves was not within the scope of 

 this problem* Therefore, the meteor- 

 ological values as actually observed 

 on the cruise vjere used In making the 

 oceanographlc forecasts Table III 

 presents this meteorological data for 

 FIGURE 4. BT TRACE, 0500Z, 20 APRIL 1951. gach day, together with the mean dally 

 altitude of the sun and the number of hours of sunlight. The 

 values for the sun's altitude were extracted from tables In 

 the air almanac for 19^1 and H.O. Pub, No. 219, by assujning a 



mean dally hour angle of [j.5° during the daylight hours, 

 b. Procedure 

 (1) Radiation (see Sec, 2 above) 



21 





