MISCELLANEOUS METEOROLOGICAL PHENOMENA 
GENERAL REMARKS 
The original meteorological program of the Carne- 
gie [41] called for hourly observations of wind direction 
and speed, and state of the sea and weather, four-hour 
reports by watch officers of wet- and dry-bulb temper- 
atures and special observations of atmospheric refrac- 
tion (by dip-of-horizon measurers at 08h, 12h, and 16h, 
and by sextant observations on the Sun or Venus when 
these bodies were near the zenith), occurrence of thun- 
der and lightning, cloud forms and amount, dust content 
of the air, etc. Owing to the loss of the original logbook, 
-however, it has been impossible to study these data in 
detail and to present separate chapters on each of these 
elements in this report. Nevertheless, certain data, in- 
cluding those concerning rainfall, thunderstorms, fog, 
and optical phenomena, have been entered in the log ab- 
stract and are included here. 
Data on clouds, wind, and state of the sea are avail- 
able only from the reports of the Greenwich mean noon 
observations. It is realized that these noon observa- 
tions are not comparable as between the various regions 
with respect to local time; therefore, too much empha- 
sis should not be placed on regional variations in these 
data. It appears desirable, on future expeditions like 
that of the Carnegie, to record the noon observations ac- 
cording to local time rather than at Greenwich noon. 
WIND 
As has been explained, the data on wind speed and 
direction are available only for the observations at 
Greenwich mean noon, and therefore these data are not 
strictly comparable as between the various Groups. 
Wind speed has been reported according to the Beaufort 
scale of wind force. 
Table 64 shows the frequency of occurrence of the 
various Beaufort numbers for all Groups. It may be 
mentioned that the wind force was 4 or less on 83.9 per 
cent of all days of the cruise. 
The mean wind force for the various Groups of Car- 
negie data are presented in table 65, which indicates 
that wind velocities were highest (4.3) in the Alaskan 
Peninsula Group for the period between July 4 and 21, 
1929, whereas the lowest mean value (2.2) is recorded 
for the Hawaiian Group for the period between Septem - 
ber 9 and 16, 1929. 
The mean Beaufort numbers for the various ranges 
of latitude are given in figure 18. Wind velocities ap- 
Table 64. Wind-speed frequencies of Beaufort numbers 
at noon (GMT) for all groups, Carnegie, 1928-29 


Percent- 


Percent- | Beau- 


fort age of fort age of 
No. total days No. total days 
0 18 4.9 5 42 11.4 
1 28 7.6 6 13 3.6 
2 52 14.2 7 3 0.8 
3 88 24.0 8 1 0.3 
4 122 33.2 
Total 367 100.0 

55 
pear to show maxima at mean latitudes 20° south, at the 
equator, 20° north, and 50° north, and minima at 30° 
south, 10° south, 10° north, and 30° north. The highest 
mean velocity (4.1) appears within the range 45° to 55° 
north. 
Data concerning the prevailing wind directions for 
the various groups are presented in table 66. 
STATE OF THE SEA 
Data concerning the state of the sea have been re- 
ported according to the International Scale, andare pre- 
sented in this report in a manner similar to that of the 
wind data (tables 67, 68, and fig. 18). The state of the 
sea appears to vary directly with wind speed. 
RAINFALL 
The days on which precipitation was recorded com- 
prise the only data concerning rainfall entered in the ob 
log abstract. These log entries indicate that precipita- 
tion occurred on 112 days during the cruise, or on 34 
per cent of the total days. As indicated by the data in 
table 69, there is considerable variation between the 
Groups in the percentage of days with rain. This, how- 
Table 65. Wind speed: Mean Beaufort numbers 
at noon (GMT) for groups, Carnegie, 1928-29 

Mean 
No. : 
Group wind 
aes | as | force 
1928 
I July 29-Aug. 6 9 3.2 
0 Aug. 7-10 4 3.8 
III Aug. 11-23 13 3.4 
IV Aug. 24-Sep. 15 # 24 2.3 
Vv Oct. 2-10 9 3.6 
VI Oct. 26-Nov. 6 12 3.4 
vil 
a Nov. 7-Dec. 21> 38 Sel 
b Feb. 22-28, 1929 7 3.6 
VIII Dec. 22-31 ° 10 3.4 
1929 
Ix Jan. 1-14 14 2.9 
x Feb. 6-17 , 12 3.4 
XI Mar. 1-31 24 2.4 
XII Apr. 22-May 31° 35 3.5 
XI 
a) June 1-30! 14 2.4 
te} July 1-3 3 3.3 
XIV July 4-218 18 4.3 
XV July 22-28 7 4.1 
XVI Sep. 4-8 5 3.0 
XVII 
a Sep. 9-16 8 YD 
b Sep. 17-Oct. 75 12 3.8 
c Oct. 11-251 16 3.6 
Oct. 26-Nov. 14 24 2.6 
Total and mean 318 ace 
Days omitted as follows: (a) Aug. 25, 26; 
(b) Dec. 3-12; (c) Dec. 25, 26; (d) Mar. 4, 13-20, 
26; (e) May 6, 11, 20-25; (f) June 8-24; (g) Two 
dates July 14 on crossing 180° meridian; (h) Sep. 
20-Oct. 2; (i) Oct. 18. 
