FROM 



THE 



ARCHIVES 



OF THE 



WOODS HOLE OCEANOGRAPHIC INSTITUTION 

 WOODS HOLE, MASSACHUSETTS 



PHYSICAL OCEANOGRAPHY OF THE GULF OF MAINE 



By HENRY B. BIGELOW 



Museum of Comparative Zoology, Harvard University 



With the collaboration of R. Parmenter and E. H. Smith 



CONTENTS 



Page 



Introduction 513 



Oceanographic history 513 



1. Gulf of Maine proper 513 



2. Continental shelf south of Nantucket 



and Marthas Vineyard — 517 



Topography . 518 



Depth of the gulf 519 



Banks and sinks 519 



Watershed 521 



Temperature 522 



February and March 522 



Surface 522 



Vertical distribution 523 



40 meters 524 



100 meters and deeper 526 



Profiles 529 



Bottom 542 



Annual variations in temperature in 



early spring 543 



Vernal warming 546 



April 550 



May 556 



Surface 556 



Below the surface 564 



June 571 



Rate of warming 572 



General distribution of temperature. 580 



July and August 585 



Surface 585 



Temperature gradient in the upper 



lOOmeters 596 



Temperature gradient in depths 



greater than 100 meters 602 



Temperature gradient on the offshore 



banks 604 



Temperature gradient along the con- 

 tinental edge 605 



40 meters 607 



Page 

 Temperature— Continued. 



July and August — Continued. 



lOOmeters 610 



150 meters and deeper 613 



Profiles 615 



Bottom 624 



Annual variations in summer temper- 

 ature 626 



Autumnal cooling 636 



Surface 636 



Subsurface 638 



November and December 645 



Mid-winter 651 



Thermal summaries 662 



1. Mouth of Massachusetts Bay, oflf 



Gloucester 662 



2. Bay of Fundy 664 



3. Near Mount Desert Island 665 



4. Western side of the basin 665 



Relationship between the temperature 



of the surface and of the air 668 



Factors governing the temperature of the 



Gulf of Maine 674 



Solar warming 674 



Dispersal of heat downward into the 



water 678 



Thermal effects of upwellings 679 



Thermal efi^ects of horizontal circulation 



of the gulf 679 



Thermal effects of evaporation 680 



Thermal efifects of the Nova Scotian 



current 680 



Thermal effects of the slope water 690 



Winter chilling 692 



Table of normal air temperatures 695 



Chilling effect of melting snow 696 



Chilling effect of melting ice 697 



Thermal effect of river water 699 



Summary of thermal determinants 699 



511 



