12 



UPPER -WIND OBSERVATIONS OF LAST CRUISE OF CARNEGIE 



southerly winds were found,- which turned to southwest 

 at heights from 3 to 8.5 km. In the region from longi- 

 tude 190° to 210° west and latitudes 15° to 20° north the 

 winds were from east and east -southeast up to levels of 

 6 km, although in flights 96 and 97, extending beyond 

 this height, there was a shift to east-northeast above 6 

 km. In the few isolated observations made about 1000 

 km northeast of the Marshall Islands east-northeast 

 winds blew from the surface up to the greatest heights. 

 These winds are controlled by the great high-pressure 

 center north of the Hawaiian Islands, which is increas- 

 ing the area under its influence during May to June. 

 E. A. Beals has found at Guam for the greater part of 

 the year east -northeast winds from the surface to the 

 limit of observation [6]. These are set up by the enor- 

 mous insolation over Australia. This east-northeast drift 

 has great uniformity of velocity with a mean velocity at 

 0.50 km above the surface of about 8 m per second, and 

 decreasing gradually to 5 m per second at levels of 6 to 

 8 km. The observations were made not far from a line 

 of divergence, the air to the north moving northward, as 

 was frequently found in the next group of Carnegie 

 flights, whereas to the south the winds move southeast. 

 Along meridian 216° west from 25° north to Yoko- 

 hama (35° north), the prevailing winds were from south 

 or west at the surface, turning to a uniform southwest 

 drift at 4 km and continuing from this direction to 5.5 

 km, the highest point reached. The westerly winds were 

 associated with a cyclone which had its center northward 

 of the Carnegie position. 



Pacific Ocean off Japan 



In the extreme northeastern part of the Pacific 

 Ocean, in latitudes 36° to 40° north, the surface winds 

 were variable. The winds at 3 km and upward were 

 found to blow from directions equally varied, but gener- 

 ally opposite to the surface direction. The wind shifts 

 were frequently abrupt and occurred at various heights. 

 In the northern summer when these flights were made, 

 this area is dominated exclusively by the central Pacif- 

 ic high-pressure area, the Aleutian low having disap- 



peared at this season. The resultant southwest surface 

 wind shows this underlying effect, but the passage of lo- 

 cal centers of high and low pressure renders the indi- 

 vidual observations of comparatively small value. 



Trades and Antitrades East of 

 the Latitudes of the Hawaiian Islands 



There was fortunately a considerable number of ob- 

 servations of the surface and upper winds overlying the 

 area between San Francisco and Honolulu. In the east- 

 erly part of this voyage to Honolulu the surface winds 

 observed were northerly, with a tendency to veer around 

 to east at 1.5 km and even to southeast in some flights. 



Along the northern limit of the northeast trades the 

 surface winds were variable and marked by the passage 

 of a small center of high pressure. Over the area lying 

 from longitude 120° to 160° west, and from the Tropic of 

 Cancer northward to latitude 30° north, the winds at the 

 surface and lower levels blew steadily from east and 

 northeast. The single high flight in latitude 25° north, 

 showed that northeast winds turned to southeast at 5 km, 

 south at 6 km, and blew strongly from southwest from 8 

 to 9 km. In the study of upper winds at Honolulu, E. A. 

 Beals [6, pp. 222-226] found that the frequency of east 

 and east-northeast winds decreases rapidly above 2 km, 

 and that the southwest drift first makes itself pro- 

 nounced at 6 km. The southwest winds doubtless come 

 down to lower and lower levels at increasing latitudes 

 north of Honolulu until they reach the surface through- 

 out the year at about latitude 35° north [1, p. 468]. The 

 Carnegie encountered these strong westerly surface 

 winds in latitude 34° north during October, and a few 

 days earlier in latitudes 31.°6 and 33 ?0 north at heights 

 of 3 and 1.5 km respectively. South of latitude 20° north 

 the few flights showed generally strong northeast trades 

 overrun by an easterly drift. Above the easterly drift 

 the winds at varying heights turned through south to 

 southwest. In latitude 15.°9 north, south winds occurred 

 at 2 km, whereas in latitude 9.°9 north they occurred on- 

 ly above 6 km. 



HEIGHT OF CLOUDS OVER THE PACinC OCEAN 



Table 4. Estimated height of cloud above surface of ocean as determined from disappearance of pilot balloons 



into cloud mass 



All flights in which the observer stated that the bal- 

 loon was lost sight of on account of clouds, either en- 

 tirely or for a time, were analyzed to determine, as far 

 as the data permitted, the height of clouds over the 



ocean. The observer noted in his record balloons "en- 

 tering cloud" and those passing "behind cloud." Thus, 

 when a tan balloon passed in front of a cloud--especial- 

 ly one with a white background, such as a cumulus 



