12 METEOROLOGICAL RESULTS OF LAST CRUISE OF CARNEGIE 
Table 16. Comparison of mean phases of 6-hour waves of atmospheric 
pressure between latitudes 15° north and 15° south after Hann and 
Pramanik, and from Carnegie, 1928-29 
Mean angle 
Source (phase Remarks 
Carnegie, ali data 174.0 118 days, chiefly summer 
Hann, oceanic data 139.6 430 days, all seasons 
Pramanik, coastal stations 105.0 8 stations, summer 
Pramanik, stations on land 294.4 4 stations, summer 
has a maximum (about 0.061) at about 25° latitude and 
decreases to about 0.022 at 5° latitude, but decreases 
little up to about 50° iatitude. 
3. The annual mean phase Ag, is fairly constant 
from latitude 20° up to about 50°, its value being about 
225° for coast and inland stations alike. The phase de- 
creases toward the equator, being about 140° in 5° lati- 
tude. 
4. The phase in summer is very irregular, in win- 
ter it is regular, being 200° or 210° from about 15° to 
50° latitude, but decreasing somewhat toward the equa- 
tor. 
5. The phase appears to be considerably less over 
the oceans and oceanic islands than at land stations, 
though the amplitudes are of the same order. 
6. There appears to be no regular dependence of 
amplitude and phase on altitude. 
7. There are considerable variations of amplitude 
and phase at individual stations in any latitude, particu- 
larly in summer. 
The results obtained by Sverdrup [17, p. 211) show a 
surprisingly close agreement with Pramanik s conclu- 
sions. 
Considering the small amount of Carnegie data, and 
the preponderance of observations made during the sum- 
mer months, it would be unreasonable to expect any 
great degree oi regularity in the Fourier coefficients 
for the 6-hour wave (fig. 10). The distribution by quad- 
rants of the eleven values of $4 illustrates this irregu- 
larity. They occur in the first, second, third, andfourth 
quadrants in the order 2, 4, 4, and i, respectively. 
Pramanik found the distribution of ¢4 in these quadrants 
for thirty-one coastal stations during the summer 
months to be 8, 6, 11, and 6, respectively. Table 16 
gives the results of a comparison oi the Carnegie phase 
angle for a mean of data between latitudes +50°, with 
some data from Pramanik [19] averaged for these lati- 
tudes where the seasonal effect should be small. There 
appears to be close agreement in phase between the 
Carnegie values and the coastal observations of 
Pramanik, but there is a marked difference between 
these values and the phase at his inland stations. 
The mean amplitude of this wave for all the Carne- 
gie Groups (as determined from the means of the values 
of aq and bggiven in table 9) is 0.007 mm. This is very 
nearly the same value (0.008 mm) arrived at by Praman- 
ik for his coastal stations in summer, and exacily the 
same amplitude that he obtained for the mean value in 
summer, for thirty-four inland stations. It is interest- 
ing to note that this apparent condition of an amplitude 
independent of ocean or land position, and of a phase 
angle smaller over sea than over land, is the reverse of 
that found for the 12-hour period. For the latter it ap- 
pears that the phase angle is independent of iand or 
ocean position, and that the amplitude is greater over 
land than over the sea. 
CONCLUSION 
In concluding the section on atmospheric pressure, 
it might be well to repeat that the amount of Carnegie 
data is relatively small and thus the-probable errors of 
the computations must be relatively large. These results 
should, however, serve to change some previous con- 
cepts which have been derivedthrough a similar use of 
inadequate data, and it is probable that further pressure 
observational work at sea will lead to some modifica- 
ions of the views which have been presented here. 
