48 METEOROLOGICAL RESULTS OF LAST CRUISE OF CARNEGIE 
Table 55. Absolute maximum and minimum relative 
humidity for groups, Carnegie, 1928-29 

Daily range 
Geoup Maximum Maximum Minimum 
o/o o/o o/o o/o 
I 98 17 14 
0 96 69 a1 10 
pant 90 65 19 5 
IV 92 61 19 5 
Vv 90 65 14 4 
VI 97 74 18 6 
vl 
(a 99 64 31> 7 
te) 78 65 13 5 
VIII 99 68 22 5 
Ix 93 58 17 8 
x 90 57 20 4 
XI 92 65 20 6 
XI 93 66 20 6 
XII 
a) 99 716 17 5 
3} 91 74 15 8 
XIV 100» 81 17 3a 
XV 97 73 22 11 
XVI 87 63 21 ist 
XVII 
a 82 57 14 6 
= 88 58 20 5 
c) 92 63 23 9 
XVII 92 534 21 5 

2 Absolute minimum value. 
Absolute maximum value. 
Table 56. Mean maximum and minimum relative 
humidity for groups, Carnegie, 1928-29 
G Mean 
ks Maximum © Daily range© 
o/o o/o o/o 
I 91.3 81.8 9.5 
I 87.2 73.0 14.2 
Ill 85.5 77.0 8.5 
IV 85.7 73.0 12.7 
Vv 84.2 74.3 9.9 
VI 91.8 81.2 10.6 
VII 
{R} 87.5 73.0 14.5 
b 76.7 68.1 8.6 
Vill 91.9 80.3 11.6 
Kx. 81.0 68.4 12.6 
x 81.3 70.9 10.4 
XI 80.9 69.1 11.8 
XII 84.9 74.2 10.7 
XIII 
{a 92.6 80.6 12.0 
b 86.7 75.7 11.0 
XIV 98.45 91.05 7.42 
XV 92.9 Tien 15.85 
XVI 84.2 69.6 14.6 
XVII 
a) 73.62 64.22 9.4 
3 79.8 66.5 323 
c 86.0 fe ar 
XVIII 82.7 71.0 U7. 
Weighted 
mean 86.02 74.43 11.59 
4 Minimum value. b Maximum value. 
c Unperiodic. 
The frequencies of hours of minimum relative hu- 
midity are given in table 58, which shows that the mini- 
mum value occurs at 13h with the greatest frequency, 
coinciding with the hour of maximum temperature. An 
attempt was made to determine the most frequent hour 
of occurrence of maximum relative humidity, but it was 
found that the data presented an almost complete scat- 
ter. There is slight indication of a maximum frequency 
at 04h, however; the values at 03h, 04h, 05h, 06h, 07h, 
and 08h are 24, 41, 31, 36, 28, and 22 cases respective- 
ly. 
Diurnal Variation of Relative Humidity 
General Remarks 
As shown in table 59, the diurnal variation of rela- 
tive humidity is small, as was also found to be the case 
with sea-surface and air temperatures, and with vapor 
pressure. On 76 per cent of all days of the cruise, the 
diurnal variation was less than 15 per cent, certainly an 
insignificant mean variation when compared with rela- 
tive-humidity ranges in continental or even insular areas. 
Diurnal Variation of Relative Humidity for all Days 
It would be expected that the diurnal curve of mean 
hourly relative humidity would present a mirror image 
of the curves of vapor pressure and air and sea temper- 
ature. Figure 31 demonstrates that this supposition is 
true in the case of the Carnegie data. There appears to 
be a well-defined minimum relative humidity at 13h with 
a less-pronounced maximum at 04h. Comparing the 
curves of vapor pressure with those of relative humidity, 
it may be observed that an unusually high value for vapor 
pressure exists at 04h, which undoubtedly gives a some- 
Table 57. Hour of mean maximum and minimum 
relative humidity, Carnegie, 1928-29 
Group | Larr | = Means mr ere a 
h o/o h o/o 
I 23 89.0 12 83.9 
II 9 83.8 16 17.2 
I 7 83.7 14 78.2 
IV 4 81.8 11 74.9 
Vv 6 81.1 14 76.5 
VI 6 88.5 15, 16 84.4 
vu 
a 4 83.3 13 75.7 
{a 2 74.9 13 69.7 
Vill 1 88.6 Pe ils} 84.0 
Ix 20, 21 dikiexd 11 Lilet 
xX 1 79.1 14 73.6 
XI 1 TT.4 1) 10.7 
XII 23 81.2 12 76.2 
XI 
a 4 89.5 14 83.7 
{3 4 84.0 10 77.6 
XIV 8 96.4 15 92.4 
XV 22 ?, 86.4 13 80.3 
XVI 0 81.2 15 72.4 
x 
va 6 71.9 15 66.4 
b 3 76.6 ill 69.1 
c 3 82.1 11 78.6 
XVII 2 79.4 12, 15 73.0 
@ Periodic 
