18 METEOROLOGICAL RESULTS OF LAST CRUISE OF CARNEGIE 
mained within the Peruvian Current throughout a con- 
siderable range of latitude, thus experiencing a greater 
uniformity of both sea-surface and air temperature. 
There is a more rapid decrease in air temperature 
beyond mean latitude 20° south. 
Dry-Bulb Lapse Rates 
Between Deck, Crosstrees, and Mainmast 
As has previously been explained, it was not possi- 
ble to obtain continuous records of lapse rates from the 
Hartmann and Braun records at various heights above 
the deck because of the impossibility of correcting these 
records for radiation effects. It was hoped, however, 
that it would be possible to study lapse rates on days 
when an Assmann calibration was made with the Hart- - 
mann and Braun instruments. Unfortunately, these data 
are extremely fragmentary because of the loss of many 
original records. The lapse rates recorded were usual- 
ly normal, but three specific cases have been selected 
for discussion because they all are decidedly superadi- 
abatic. These data are presented in figure 15. Miss 
Clarke has previously discussed these unusual lapse 
rates [23] as follows: 
1. July 29, 1928, at 12h, off the coast of Iceland: The 
dry-bulb at the masthead (34.6 meters above sea level) 
was 1°5 lower than the deck dry-bulb, a lapse rate equal 
to four times the dry adiabatic. The weather was cloud- 
y with a moderate northwest breeze, sea moderate with 
surface temperature of 11°6. 
2. January 14, 1929, at 10h local mean time, enter- 
ing the port of Callao: There was a dry-bulb tempera- 
ture lapse of 2°1 from deck to crosstrees and of 0°5 
from crosstrees to masthead, a total lapse of 2°6 in 35 
meters or seven times the dry adiabatic. Wind was south 
southeast, force 3, weather cloudy, sea-surface temper- 
ature 18°8. 
3. March 12, 1929, at 11h local mean time, approach- 
ing the island of Tahiti: The dry-bulb lapse rate was 
2°0 from deck to crosstrees and 0°8 from crosstrees to 
masthead, a total of 2°8 or seven times the dry adiabatic. 
Weather was squally with gentle northwest breeze. Sea- 
surface temperature was 28°3. 
If the deck readings are ignored, the lapse rates be- 
tween crosstrees and masthead are respectively two, 
four, and six times the dry adiabatic. : 
It is not implied that these excessive lapse rates 
represent actual conditions over the ocean. In all prob- 
ability the observed values were greatly influenced by 
radiation from deck, shelter, and sails, but it is possi- 
ble that such conditions might prevail over a small area 
for short periods of time. 
Maxima and Minima of Air Temperature 
The absolute maximum and minimum air tempera- 
tures for the various groups are presented in table 21 
without comment except to state that in most cases 
these absolute extremes of temperature were recorded 
during clear, calm weather, and for this reason were 
probably influenced by deck temperatures to some ex- 
tent. Quite frequently the maximum and minimum air 
temperatures during a 24-hour period occurredat times 
when the vessel was not under way, and thus when deck 
Table 20. Difference between temperature readings in degrees centigrade of Hartmann and Braun 
instruments on deck and on crosstrees for nine days when sky was partly clear to 
cloudy (particularly during midday hours), Carnegie, 1928-29 

Local mean hours 
[4-5 | 5-6 | 6-7 | 7-8 | 8-9 | 9-10 | 


11-12 
° 

Y 1928 ° ° ° ° ° Re 
Oct. 5 1.3 1.1 1.3 1.4 1.2 1.1 1.5 2.2 2.0 1.8 1.5 1.2 
Nov. 14 1.9 0.9 1.3 1.6 1.4 1.2 1.4 1.8 1.0 0.7 0.3 0.1 
Nov. 20 1.3 1.3 1.6 1.6 1.3 1.8 let! 1.6 iki 0.9 0.8 0.7 
Nov. 27 1.5 0.5 1.5 1.3 1.0 1.3 1.5 1.3 1.5 0.3 0.6 0.3 
Dec. 1 1.6 1.2 1.6 1.6 1.5 1.4 1.6 1.6 1.2 0.7 0.7 0.6 
Dec. 18) lei 1.4 1.5 1.5 1.5 1.8 1.3 1.4 1.5 1.2 0.6 0.1 
Dec. 25 1.4 1.5 1.4 1.5 alent 1.3 1.4 ile 1.4 1.3 1.0 0.8 
1929 
Jan. 4 1.5 1.4 1.2 Iot/ 1.2 1.4 1.0 1.4 1.1 1.3 1.4 0.5 
Jan. 13 1.1 1.3 ail 1.2 rust 1.3 1.4 1.5 1.2 1.0 0.5 0.0 
Mean 1.5 1.2 1.4 1.5 1.3 1.4 1.4 1.5 1.3 1.0 0.8 0.5 

1928 i 
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Local mean hours 
rie-17 [17-18 [18-19 [19-20 [20-21 [21-22 | 22-28 [29-24 
Le ee — Dl lad 
7 1.3 1.4 1.0 1.4 1.5 1.2 
6 1.0 1.5 1.3 1.4 1.4 1.3 
3 1.3 1.5 1.3 1.1 1.4 1.3 
2 1.0 1.6 1.5 1.1 1.5 1.6 
9 ee 1.3 1.3 1.5 1.6 1.5 
0 isi 1.4 1.7 1.8 1.5 1.5 
9 1 1.0 1.5 1.3 1.2 1.4 
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sil 2.0 1.3 1.3 1.3 1.4 1.3 
0 1.2 1.3 1.3 1.4 1.5 1.4 



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