PHYSICAL OCEANOGRAPHY OP THE GULF OF MAINE 
669 
Amount by which the air was warmer than surface water, April 6 to 20, 1920 
General locality 
Station 
Date 
Time 
Amount 
by which 
air was 
warmer 
than 
water, 
°C. 
Off Boston Harbor,. — ... 
20089 
Apr. 6 
3 p. m 
5.5 
20090 
Apr. 9 
10.15 a. m - 
1.0 
Off Cape Ann 
20091 
— /do 
1.50 p. m 
5.7 
20092 
do 
5 p. m 
2.5 
20093 
do 
10.30 p. m 
.8 
20094 
Apr. 10 
3 a. m 
1. 1 
20095 
do 
8 a. m 
1.9 
20096 
...do 
12.20 p. m. 
9.4 
Off Penobscot Bay 
20097 
...do 
11 p. m 
1.0 
20098 
4 p. m 
3.6 
20099 
Apr. 12 
1 p. m 
6.3 
20100 
do 
4.30 p. in 
3.9 
Do ...1 __ 
20101 
9.30 p. m 
3.5 
Off Yarmouth, Nova Scotia 
20102 
Apr. 13 
2.15 a. m 
3.9 
20103 
Apr. 15 
1 p. m 
6. 7 
Off Seal Island, Nova Scotia 
20104 
do 
6 p. m 
4.7 
North Channel 
20105 
do 
9.15 p. m 
4. 1 
20106 
Apr. 16 
3.5 
Eastern Channel 
20107 
do 
East edge of Georges Bank 
20108 
do 
6.4 
Southeast slope of Georges Bank 
20109 
do 
5.8 
East part of Georges Bank _ _ 
20110 
...do 
8.30 p. m 
6. 1 
Do- — - 
20111 
Apr. 17 
3.6 
Southeast part of basin 
20112 
do 
.7 
20113 
3.8 
20114 
3.3 
Basin off Cape Ann 
20115 
Apr. 18 
3.40 p. m. _ 
2.0 
Off Cape Cod 
20116 
../do 
3. 0 
Do 
20117 
...do 
1 p. m 
4. 6 
Cape Cod Bay 
20118 
Apr. 20 
8.3 
Mouth of Massachusetts Bay 
201 19 
8.20 p. m 
6. 9 
The air averaged about 5° warmer than the water in Massachusetts Bay, along 
Cape Cod, and out across Georges Bank to the continental edge by May 16 to 17, 
1920 (run from station 20123 to station 20129), with the difference greatest (10°) 
in Massachusetts Bay from 10 a. m. to 1 p. m., least (1.4°) at 9 p. m., but increas- 
ing again to 4° to 5.5° over Georges Bank during the daylight hours of the next day. 
In any partially inclosed body of water, such as the Gulf of Maine, where the 
wind may blow either out from the land over the water or in from the open sea, the 
relation of water to air temperature depends largely on the strength and direction 
of the wind at any particular moment. For instance, the Halcyon recorded an air 
temperature of 23.3° C. and surface reading of 14.44° while fishing on Platts Bank 
on July 27, 1924, at 5 a. m. in a flat calm; but shortly afterward a breeze coming in 
from the south — from the open sea — lowered the temperature of the air to 15.6°, with 
no change in the water. On the whole, however, the difference between air and water 
during the part of the year when the air is the warmer certainly rules greatest by 
day, when the sun’s heat pours down, and least by night. For instance, the air was 
3° to 4° warmer than the water from 7 a. m. to 5 p. m. on the run out to the basin 
off Cape Ann on July 15 to 16, 1912, and only about 1.5° to 2° warmer than the 
water from 9 p. m. to 1 a. m. 
8951—28 43 
