230 
PACIFIC SCIENCE, Vol. IV, July, 1950 
200-, and 300-foot levels. To obtain Figure 
16, the highest monthly average temperature 
at each depth in each quadrangle was plotted, 
regardless of the month or year in which it 
occurred, and isotherms were drawn. Figure 
17 was prepared similarly for lowest monthly 
average temperatures. 
The highest single surface temperature re- 
corded in the Hawaiian Island area was 90° 
F. at 19° N and 157° W in August, 1942, 
while the lowest single temperature recorded 
was 60.9° F. at 28° N and 163° W in 
January, 1947. 
Annual sea temperatures at a depth 
of 400 feet 
As is apparent in Figures 22 and 27, sea 
temperatures at a depth of 400 feet have only 
a small annual variation. Values for all 
months of the year have therefore been aver- 
aged together by 1 -degree quadrangles to ob- 
tain the annual average. These annual aver- 
ages were plotted by position and isotherms 
drawn ( see Figure 15). This figure, when 
compared with Figures 22 and 27, indicates 
that at 400 feet the variation of sea tempera- 
ture with position greatly exceeds the varia- 
tion with time. 
Comparison of average temperatures in dif- 
ferent years 
Figure 18 compares the annual variation 
of temperature at the surface, 100 feet, 200 
feet, and 300 feet for each of the years 1943 
to 1947 with the average annual variation 
for all years combined. There is considerable 
difference between the curves representing 
different years. The year 1943 was warmer 
than average at the surface and 100 feet. Not 
enough data were available to show the de- 
viation at 200 feet and at 300 feet in this 
year. The year 1944 was virtually an average 
year at the upper two levels, while at the two 
lower levels there was some variation from 
the average. The year 1945 was definitely a 
warmer-than-average year in the upper two 
levels, while in the lower two it was generally 
warmer with a few months colder than aver- 
age. The first part of the year 1946 was def- 
initely warmer than average, while the latter 
part of the year was colder than average at 
all levels. The year 1947 was a colder-than- 
average year at all levels with the deviation 
being the greatest in the upper 100 feet. 
Average temperature in the vicinity of Oahu 
Figure 19 shows the temperature distribu- 
tion in the vicinity of Oahu for the surface, 
100 feet, 200 feet, and 300 feet. The iso- 
therms at each depth are based upon averages 
computed for each 10-minute quadrangle of 
latitude and longitude. Thus the details of 
the average temperature distribution near 
Oahu are shown. In this region many obser- 
vations are available and detailed information 
may have practical value. 
VERTICAL TEMPERATURE DISTRIBUTION 
Southwest-northeast cross section 
Figures 20 and 21 present average 
southwest- northeast temperature -depth sec- 
tions for winter and summer months, respec- 
tively. All available bathythermograms for 
the two periods of time, and within the band 
denoted in Figure 1, were used to obtain the 
averages at various positions and depths. 
These averages form the basis of the sections. 
Monthly average temperature-depth curves 
Figure 22 shows curves through the aver- 
age temperatures at different depths for a 5- 
degree quadrangle covering the area 20° to 
25° N and 155° to l60° W. These curves 
were obtained by averaging all available 
temperatures for each month at 10-foot 
depth intervals down to 100 feet and at 25- 
foot intervals down to 425 feet, plotting 
these averages against depth, and joining 
the points. Such curves do not show the 
typical temperature-depth structure because 
of smoothing which occurs in averaging. The 
number of temperatures included in the aver- 
age is shown beside each point. 
