SEA-SURFACE TEMPERATURE 
\ 
Table 31. Mean hourly values of sea-surface temperature, in degrees centigrade, for groups, 
Carnegie, 1928-29--Concluded 
29 
Local mean hours 
pe Laban aer | a7 te ven eeeor | ean eer as | Meee 
1e 16; XG 2¢ Xe °C XG °C we AG ac 
I 10.54 10.46 10.48 10.47 410.60 10.64 10.62 10.47 10.43 10.48 10.46 
U 19.04 19.68 19.79 19.35 19.71 20.02 20.00 20.06 20.17 19.78 19.30 
It 26.47 26.50 26.50 26.45 26.34 26.34 26.31 26.39 26.40 26.43 26.35 
IV 27.93 27.96 27.88 27.81 27.72 27.66 27.58 27.56 27.52 27.44 27.58 
Vv 28.66 28.59 28.56 28.42 28.47 28.38 28.35 28.30 28.30 28.32 28.44 
VI 26.62 26.61 26.63 26.58 26.56 26.52 26.52 26.48 26.54 26.54 26.56 
Vii 
a 21.95 21.95 21.89 21.82 21.78 21.73 21.63 21.62 21.57 21.53 21.73 
b 26.28 26.28 26.29 26.24 26.28 26.25 26.19 26.18 26.18 26.18 26.22 
vill 17.85 17.68 17.68 17.64 17.54 17.38 17.44 17.37 17.34 17.25 17.45 
Ix 20.24 20.27 20.14 19.88 20.01 19.85 19.97 19.86 19.85 19.85 19.97 
x 24.08 24.09 24.13 24.22 24.11 24.04 23.98 23.93 23.88 23.82 23.98 
XI 28.55 28.60 28.58 28.53 28.41 28.34 28.27 28.26 28.25 28.25 28.30 
XII 27.51 27.48 27.48 27.47 27.47 27.44 27.41 27.39 27.41 27.41 27.38 
x1 
@ 20.46 20.21 20.27- 20.18 19.94 19.97. 19.99 19.95 20.09 20.22 20.30 
b 15.15 15.54 15.10 15.23 15.68 15.71 16.06 16.02 16.09 15.88 15.43 
XIV 9.08 Ont 8.10 9.10 9.02 9.08 9.06 9.04 9.09 9.13 9.04 
XV 14.75 14.94 15.14 15.22 15.35 15.25 14.75 14.87 14.73 14.64 14.73 
XVI ‘18.95 18:97 19.01 18.88 18.82 18.56 18.65 18.67 18.81 18.84 18.97 
XVII 
(a 23.51 23.69 23.77 23.64 23.63 23.47 23.53 23.42 23.45 23.40 23.43 
b 25.58 25.52 25.46 25.39 25.38 25.34 25.39 25.42 25.37 25.30 25.41 
E 23.70 23.71 23.64 23.55 23.53 23.47 23.50 23.57 23.57 23.61 23.64 
x 28.01 28.01 27.99 27.92 27.85 27.81 27.80 27.77 27.76 27.75 27.83 
Days omitted as follows: 
26; (e) May 6, 11, 20-25; 
20- Oct. 2; (i) Oct. 18. 
Seewarte, values for 5° squares published by the ‘‘Ma- 
rine Observer,’ 1926, Pilot Charts of the Pacific and 
Atlantic oceans issued by the United States Hydrograph- 
ic Office, Memoirs of the Imperial Marine Observatory, 
Japan, 1930, and Réseau Mondial (1925) values for 10° 
Squares. Though the data from which these normal val- 
ues of sea-surface temperature have been computed are 
meager, especially for parts of the Pacific Ocean, it is 
interesting to find that the Carnegie mean values for the 
various Groups and the values given for the approximate 
mean positions of these respective Groups in the publi- 
cations cited seldom differ more than 1°. From this it 
can be inferred that temperatures of the ocean surface 
are remarkably uniform when compared with air tem- 
peratures. This reasoning, however, does not minimize 
the effect of persistent small differences in temperature 
On ocean currents, evaporation, air temperature, and 
stability. 
Even the departures of individual observations of 
temperature from normal monthly values appear to be 
everywhere small, as may be shown by comparing the 
revyersing-thermometer records of surface tempera- 
tures with monthly normals scaled from the isothermal 
charts of Schott and Schu [31]. 
From the simultaneity of change of surface temper- 
ature and salinity, Helland-Hansen [32] has concluded 
that unperiodic variations in sea-surface temperature 
must be chiefly the result of displacement of the surface 
layers. Although the series of Carnegie observations in 
such regions is short, the available data seem to bear 
out this conclusion; for example, the average areal sea- 
surface temperatures generally appear to depart from 
the normal temperatures by more than one degree only 
(a) Aug. 25, 26; (b) Dec. 3-12; (c) Dec. 25, 26; 
(f) June 8-24; (2) Two dates July 14 on crossing 180° meridian; (h) Sep. 
(d) Mar. 4, 13-20, 
along the boundaries of ocean currents where shifting 
and mixing of water masses are taking place. 
Maxima and Minima 
of Sea-Surface Temperature 
The absolute maximum sea-surface temperature re- 
corded during the cruise was 30°2 and occurred at 14h 
and 15h, November 14, 1929, in latitude 11°6 south, lon- 
gitude 163°4 west, while the vessel was approaching the 
Samoan Islands. The region around these islands was 
one of consistently high sea-surface temperatures dur- 
ing the two periods that the Carnegie spent in these wa- 
ters (March-April and November 1929). A maximum 
temperature of 30°0 was recorded at 14h, March 29, 
1929, in latitude 15°3 south, longitude 163°3 west, and 
one of 29°9 during 11h and i2h, April 26, 1929, in lati- 
tude 6°7 south, longitude 172°4 west. Sea-surface tem- 
peratures averaged above 29° throughout most of this 
part of the South Pacific Ocean. 
Temperatures averaged considerably lower in the 
North Pacific Ocean; the absolute maximum was 28°38. 
The highest sea-surface temperatures in the North At- 
lantic Ocean and Caribbean Sea were 29°1 and 29°2 re- 
spectively (see table 32). 
The absolute minimum sea-surface temperature of 
the cruise (6°4) was recorded in the North Pacific Ocean 
at noon on July 8, 1929, in latitude 46°S north, longitude 
163° east. Average temperatures almost as low -were 
recorded in the North Atlantic Ocean, but occurred in 
higher latitudes. The absolute minimum (6°9) was re- 
corded at 06h, July 14, 1928, in latitude 64°1 north, lon- 
gitude 11°4 west. It may be remarked again that these 
