WEATHER 



With ocean weather station C, at 52°45' N., 35°30' W., the nearest 

 weather station to shore stations along the western side of the 

 Atlantic during- the 1947 ice season, the meteorological observations 

 which might be made from the ice patrol surface craft assumed 

 greater importance. Accordingly, a full ocean-weather station ob- 

 serving program was planned for the patrol cutters. Both Mendota 

 and Speyicer while at sea on the ice-observation cruises made synop- 

 tic surface weather reports every 3 hours in addition to the upper- 

 air observations which included rawins, raobs, and pibals. A digest 

 of weather conditions experienced on these cruises is given in the 

 cruise summaries. From the standpoint of its effect on ice, the most 

 significant meteorological feature of the season was the abnormal 

 atmospheric circulation over the northwestern North Atlantic be- 

 fore the first of the Mendota's ice observation cruises. This oc- 

 curred during the month of February and is treated in the "Discus- 

 sion of Some of the Effects of Winds on Ice Distribution in the 

 Vicinity of the Grand Banks and the Labrador Shelf". 



COMMUNICATBONS 



As has been indicated in the introductory paragraphs of this 

 report, radio communication performs a vital function in the col- 

 lection an dissemination of ice information throughout the season 

 and in the collection of water temperature reports during a part of 

 the season. 



The times of the scheduled broadcasts of the NIDK ice bulletins 

 which are sent out twice a day were changed slightly for the 1947 

 season from 0200 and 1400 G.c.t. and 1318 G.c.t. The times of these 

 broadcasts are selected with the aim of including the maximum 

 amount of recently received information, the morning broadcast 

 including a digest of the ice reports which are received in greater 

 number during the first few hours after dawn with its improved 

 visibility, and the evening broadcast including the results of aerial 

 ice-observation flights which frequently return to the base field 

 shortly before dusk. It was considered that these objectives could 

 be attained and that there would still be enough time for the neces- 

 sary steps of preparing the broadcast, checking the broadcast 

 against source material and correction of errors, perforating the 

 tape for automatic transmission, and checking and correcting the 

 tape, if the broadcast time were advanced to the new times of 0118 

 and 1318 which would have two additional advantages. One was that 

 beginning immediately after a silent period there would be fewer 

 times when transmission of the broadcast would be suspended in 

 observation of silent periods. The other advantage was that the 

 broadcast would usually be completed during the hours when the 

 operators in single-operator ships normally would be on watch. 



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