PHYSICAL OCEANOGBAPHY OF THE GULF OF MAINE 
545 
Meters 
Mar. 1, 
1920, 
station 
20050 
Mar. 5, 
1921, 
station 
10511 
Meters 
Mar. 1, 
1920, 
station 
20050 
Mar. 5, 
1921, 
station 
10511 
0 
Degrees 
2.5 
1. 95 
1.89 
Degrees 
3. 61 
100 
Degrees 
1.52 
1.68 
Degrees 
3. 85 
3. 86 
20 
150 
40 
3. 84 
Meter 
Temperature, Centigrade 
1 ° 2 ° 3 ° 4 ® 
The winter of 1913 (Bigelow, 1914a, p. 391) was 
intermediate between 1920 and 1921 in temperature 
at this locality, with readings of 2.83° on the surface 
and 3.11° on bottom in 82 meters at a near-by loca- 
tion on February 13 (station 10053), when the mini- 
mum temperature for the winter was recorded. 
An equally interesting annual difference is that 
the temperatures of late February and early March 
were lowest at the surface in 1913 and 1921, whereas 
in 1920 vernal warming already had raised the tem- 
perature of the surface fractionally above that of the 
underlying water by March 4. On February 24 to 
28, 1925, the bottom was fractionally the warmest 
level at one deep station ( Fish Hawk station 18a), 
while the surface was warmest at another (station 2), 
with the mid-stratum fractionally the coldest at 
both. Thus, the date at which the vernal warming 
of the surface begins to be appreciable does not 
necessarily mirror the state of the preceding winter, 
whether a cold one or a warm one in this part of the 
gulf (1920 was a very cold winter), but depends 
more on the degree of cloudiness, the precise condi- 
tion of air, the direction of the wind, the tempera- 
ture of the air, and on the snowfall from the middle 
of February on. 
Turning now to the coastal belt just north of 
Cape Ann we find very little difference in actual tem- 
perature between readings of 2.4° to 3.7° at the Fish 
Hawk stations (Nos. 20 to 28) for March 10, 1925, 
and Welsh’s records of 3.8° to 3.9° on March 19, 
1913; but with the surface about 1° warmer than 
the 30-meter level at all these Fish Hawk stations, 
but the whole column virtually uniform in tempera- 
ture down to 120 meters in 1913, it is evident that 
the vernal warming of the surface commenced at 
least two weeks earlier there in 1925 than in 1913. 
The year 1920 was certainly colder at this general 
locality than either 1913 or 1925, because the surface had warmed only to 3.05 
there by the 6th of April (station 20092). 
Fig. 21.— Vertical distribution of temperature 
off Gloucester during the first week of 
March of the years 1913, 1920, and 1921, to 
show the annual variation. A, March 1, 
1920 (station 20050); B, March 5, 1921 (sta- 
tion 10511); C, March 4, 1913 (station 10054) 
