NORTHERN EDGE-RADIATION THERMOMETER 

 27 FEBRUARY 1968 



"igure I I Alignment of cumulus clouds along the north wall 



of the Gulf Stream - ESSA 3 



The radiation thermometer track of the northern edge on 27 February 1968, as de- 

 fined by the Naval Oceanographic aircraft "El Coyote", is compared in this chart to an 

 ESSA 3 satellite photograph of the cloud cover on 26 February 1968. The agreement is 

 remarkable despite grid positioning errors in satellite data, navigational errors in aircraft 

 data, and one-day separation in time. 



On 26 February 1968 a cumulus cloud deck was observed 400 m above the Gulf 

 Stream. Surface winds were northerly 10 to 15 m/sec, and air temperature was approxi- 

 mately 6°C. Water temperature varied from about 12°C in Slope Water to about 20°C in 

 the Stream. Above the northern edge of the Stream there was a sharp demarcation between 

 the clear skies to the north and the cumulus deck. (U. S. Naval Oceanographic Office) 



22 



