METEOROLOGICAL CONDITIONS DURING PILOT-BALLOON FLIGHTS 



from September 17 to 22. Skies were partly cloudy to 

 overcast in morning and evening, but clear about mid- 

 day, except for the usual cumulus clouds around the ho- 

 rizon. These flights show, from the surface up to 4 km, 

 a general northeast to east drift, occasionally getting 

 around as far as east-southeast. 



Flights 140 to 144, October 3 to 7, 1929 



The Carnegie left Honolulu on October 2, sailing a 

 course a little west of north until reaching latitude 34° 

 north on October 8. Flights 140 to 144 were made on 

 October 3, 4, 5, and 6. The weather was generally fine, 

 although a few drops of rain fell during the afternoons of 

 October 3, 4, and 5. The sky was about half overcast for 

 the whole period, slightly more cloud being encountered 

 In the more northerly latitudes. The surface winds blew 

 very steadily from between east and east-northeast, with 

 a force varying between fresh and moderate breeze, en- 

 abling the Carnegie to make almost 170 miles a day. 



Flights 145 to 150, October 7 to 13, 1929 



These flights were made along the 34° parallel of 

 latitude to the northward of the Hawaiian Islands as the 

 Carnegie sailed eastward in the northern part of a great 

 loop of her cruise to Pago Pago, Samoa. The weather 

 was broken and squally with either showers, drizzle, or 

 moderate rain every day except October 10. The sky 

 was mostly overcast, and the surface winds very varia- 

 ble. At higher levels the winds blew very steadily from 

 west-southwest with velocities from 4 to 10 m per sec- 

 ond. On October 10, although the surface wind was only 

 a light northwest air of Beaufort force 1, above 1.5 km 

 the west-southwest winds were notably strong, blowing 

 from 7 to 10 in force. 



Flights 151 to 153, 

 October 17 to 19, 1929 



These three flights on October 17, 18, and 19, form 

 a group centered about latitude 26° north--which is 1100 

 km — about four days' rim from the nearest preceding 

 and succeeding flights. Balloons were not released Oc- 

 tober 14, 15, and 16 because of squally and threatening 

 weather with rain showers and overcast or mostly over- 

 cast sky. On October 17 and 18, however, the sky was 

 mostly clear, and calms or light breezes from a south- 

 erly direction persisted. On October 19 there were fre- 

 quent rain squalls, but in a brief clearing at 1 p.m. a 

 flight was made, the sky being almost wholly overcast 

 during the rest of the day. The flight on October 17 

 showed westerly winds from the surface to 8 km. In 

 flight 152 on the following day, westerly winds did not set 

 in up to a height of 5.5 km, but persisted to 8.5 km, 

 whereas on the third day the winds above the surface 

 blew from southeast to a height of 2.5 km, where the 

 balloon was lost. 



Flights 154 to 156, October 23 to 26, 1929 



These flights were made as the Carnegie sailed 

 southward along approximately the 138th west meridian 



in the northern limits of the northeast trades. On Octo- 

 ber 23 and until the afternoon of October 24 the surface 

 winds blew from between east and north. In the after- 

 noon these winds dropped to calm, broken by brief 

 spells of light and variable breezes from the southwest 

 quadrant. These overcast skies and frequent spells of 

 rain continued on October 24 and 25, preventing any bal- 

 loon observations. On October 26, with a smooth sea 

 and light northwest breezes and airs, the balloon was 

 followed to 3 km, and on the following day, with calms 

 and easterly airs, to 7 km. 



Flight 154 showed strongly developed northeast 

 trades from the surface to 1 km, with southwest winds- 

 probably antitrades--from 3 to 4.5 km. Although at the 

 surface northwest breezes continued throughout October 

 26, flight 155 shows this northwest stratum is very thin, 

 being overrun by the northeast trades. Above the trades 

 from 1.5 to 2.5 km a transition layer moving from south- 

 west was observed on both October 23 and 26. On Octo- 

 ber 27 light northeast winds reached 2.5 km, above 

 which level the winds were more an easterly drift to 

 5.5 km, when a definite south wind was observed to a 

 height of 6.5 km. On the morning of October 28 the Car - 

 negie experienced southeast winds, showing that the 

 northeast trades were slowly carving a tunnel for them- 

 selves under the warm southerly current. 



Flights 157 and 15 8, 

 October 28 and 29, 1929 



These flights, taken 8° north of the equator, showed 

 the northeast trades well developed reaching to 5.5 

 km. It is remarkable that the northeast trades did not 

 come down to the level of the ocean; the surface winds, 

 however, were light and variable, blowing between south- 

 east and northeast with Beaufort force 1 to 3. The sky 

 continued for two days half overcast, with showers de- 

 veloping in the afternoon of October 28 at 14h 42m and 

 18h 54m. 



Flights 159 to 166, 

 November 4 to 11, 1929 



These eight flights, lying between 140° and 160° west 

 longitude, were made while the Carnegie was going south- 

 ward from 3° north to 9.°4 south latitude. These flights 

 were made a little more than six months after the group 

 84 to 91 on April 24 to 30, both at a time of the year usu- 

 ally unsettled by the change from the wet to the dry sea- 

 son. No rain occurred during this period, however, al- 

 though the skies were reported as "partly cloudy" or 

 "partly overcast" on all except November 7 and 8, when 

 they were reported as "mostly clear." 



The surface winds showed a curious transposition of 

 the trades. On November 4 and 5, while the Carnegie 

 was north of the equator, southeast breezes to light airs 

 were experienced, whereas south of the equator the winds 

 were northeast, varying from moderate to gentle breez- 

 es. The surface southeast trades were found from the 

 pilot balloons on November 4 and 5 to be a very shallow 

 stratum, reaching only 1 km on November 4 and 1.7 km 

 on November 5. Above these southeast winds there is a 

 uniform movement from northeast, and the observations 

 as far as they go show northeast winds to 4 km. Flight 

 159, made 3° north of the equator, showed northeast 



