﻿THE 
  GULF 
  STREAM 
  MARMER 
  303 
  

  

  FLUCTUATIONS 
  OF 
  THE 
  GULF 
  STREAM 
  

  

  The 
  Gulf 
  Stream 
  manifestly 
  must 
  be 
  subject 
  to 
  fluctuations 
  as 
  

   regards 
  location, 
  velocity, 
  and 
  temperature. 
  Heavy 
  winds 
  will 
  not 
  

   only 
  carry 
  its 
  waters 
  into 
  regions 
  which 
  at 
  other 
  times 
  it 
  does 
  not 
  

   invade 
  but 
  will 
  also 
  accelerate 
  or 
  retard 
  its 
  velocity. 
  Variations 
  in 
  

   barometric 
  pressure 
  likewise 
  will 
  bring 
  about 
  fluctuations 
  in 
  the 
  move- 
  

   ment 
  of 
  the 
  waters 
  of 
  the 
  stream. 
  Seasonal 
  variations 
  in 
  temperature 
  

   in 
  the 
  regions 
  through 
  which 
  it 
  flows 
  will 
  be 
  reflected 
  in 
  somewhat 
  

   similar 
  seasonal 
  variations 
  in 
  the 
  temperature 
  of 
  its 
  waters. 
  A 
  further 
  

   cause 
  for 
  its 
  fluctuation 
  is 
  found 
  in 
  the 
  fluctuations 
  of 
  the 
  currents 
  

   which 
  feed 
  it 
  or 
  which, 
  like 
  the 
  Labrador 
  Current, 
  come 
  into 
  conflict 
  

   with 
  it. 
  

  

  Fluctuations 
  in 
  the 
  velocity 
  of 
  the 
  Gulf 
  Stream 
  are 
  noted 
  by 
  Pills- 
  

   bury. 
  He 
  refers 
  to 
  an 
  occasion, 
  while 
  he 
  was 
  at 
  anchor 
  in 
  the 
  Straits 
  

   of 
  Florida, 
  when 
  the 
  velocity 
  of 
  the 
  current 
  at 
  the 
  surface 
  increased 
  

   from 
  3.3 
  knots 
  to 
  4.6 
  knots 
  in 
  less 
  than 
  an 
  hour. 
  He 
  speaks, 
  too, 
  of 
  

   "a 
  regular 
  daily 
  variation 
  in 
  velocity 
  which 
  amounts 
  in 
  some 
  instances 
  

   to 
  nearly 
  2/2 
  knots 
  " 
  (p. 
  546). 
  This 
  regular 
  daily 
  variation 
  he 
  regarded 
  

   as 
  of 
  the 
  nature 
  of 
  a 
  tidal 
  effect. 
  His 
  observations 
  were 
  later 
  sub- 
  

   jected 
  to 
  harmonic 
  analysis 
  by 
  Harris, 
  who 
  found 
  the 
  principal 
  con- 
  

   stituent 
  of 
  the 
  tidal 
  current 
  to 
  have 
  a 
  velocity 
  of 
  less 
  than 
  a 
  quarter 
  

   of 
  a 
  knot.^^ 
  The 
  tidal 
  current 
  in 
  the 
  Straits 
  of 
  Florida 
  is 
  therefore 
  

   of 
  negligible 
  velocity, 
  and 
  the 
  fluctuations 
  noted 
  by 
  Pillsbury 
  are 
  

   undoubtedly 
  irregularities 
  which 
  accompany 
  the 
  flow 
  of 
  water 
  in 
  

   large 
  masses. 
  

  

  Pillsbury 
  was 
  also 
  of 
  the 
  opinion 
  that, 
  in 
  addition 
  to 
  this 
  so-called 
  

   regular 
  daily 
  variation 
  and 
  to 
  fluctuations 
  arising 
  from 
  changes 
  in 
  

   wind 
  and 
  weather, 
  the 
  Gulf 
  Stream 
  within 
  the 
  Straits 
  of 
  Florida 
  was 
  

   subject 
  to 
  periodic 
  monthly 
  variations 
  in 
  both 
  temperature 
  and 
  

   velocity 
  which 
  depend 
  on 
  the 
  declination 
  of 
  the 
  moon. 
  The 
  observa- 
  

   tions 
  are 
  not, 
  however, 
  sufficiently 
  extensive 
  to 
  settle 
  this 
  question 
  

   definitely. 
  The 
  reality 
  of 
  such 
  variations 
  is 
  still 
  in 
  question, 
  and 
  it 
  

   would 
  not 
  be 
  at 
  all 
  surprising 
  if 
  further 
  investigation 
  should 
  disprove 
  

   any 
  such 
  relationship. 
  

  

  In 
  a 
  paper 
  before 
  the 
  American 
  Meteorological 
  Society 
  on 
  Tem- 
  

   perature 
  Variations 
  in 
  the 
  Gulf 
  Stream 
  in 
  the 
  Straits 
  of 
  Florida, 
  

   1917-1921,2^ 
  Hazel 
  V. 
  Miller 
  presented 
  the 
  results 
  of 
  a 
  study 
  of 
  

   several 
  thousand 
  readings 
  of 
  surface-water 
  temperature 
  made 
  by 
  

   observers 
  on 
  the 
  Key 
  West-Habana 
  car 
  ferries 
  across 
  the 
  Straits 
  of 
  

   Florida 
  for 
  the 
  4-year 
  period 
  1917-1921. 
  The 
  temperature 
  was 
  

   found 
  to 
  range 
  from 
  a 
  minimum 
  of 
  about 
  76° 
  in 
  January 
  to 
  about 
  86° 
  

  

  22 
  R. 
  A. 
  Harris: 
  Manual 
  of 
  Tides, 
  Part 
  V; 
  Currents, 
  Shallow- 
  Water 
  Tides, 
  Meteorological 
  Tides, 
  and 
  

   Miscellaneous 
  Matters, 
  U. 
  S. 
  Coast 
  and 
  Geodetic 
  Survey 
  Rep. 
  for 
  the 
  Year 
  Ending 
  June 
  30, 
  1907, 
  Appen- 
  

   dix 
  6, 
  pp. 
  231-545 
  Washington, 
  1907; 
  reference 
  on 
  pp. 
  411-412. 
  

  

  " 
  Abstract 
  in 
  Bull. 
  Amer. 
  Meteorol. 
  Soc, 
  Vol. 
  7, 
  pp. 
  87-88, 
  1926. 
  

  

  