Atlantic Ocean and Gulf Stream

ocean flows colored with sea surface temperature data
ocean flows colored with sea surface temperature data
Source: National Aeronautics and Space Administration (NASA) Scientific Visualization Studio, Gulf Stream Sea Surface Currents and Temperatures

The Gulf Stream is a current of warm water, sometimes 15-20°F warmer than the adjacent water, flowing north from the equator.

The current warms the eastern edge of the North American continent in winter. That heat exchange is part of the entire Atlantic Meridional Overturning Circulation (AMOC), where cold water from the Arctic and warm water from the tropics transfer energy around the globe.1

ocean flows colored with sea surface temperature data
ocean flows colored with sea surface temperature data
(red pixels are warmer areas approaching 25°C, greens are intermediate values of 12-13°C, and blues are less than 10°C)
Source: National Aeronautics and Space Administration (NASA) Scientific Visualization Studio, Gulf Stream’s Brightness Temperature (May 2, 2001)

The flow of the Gulf Stream affects shipping patterns. In 1768, Benjamin Franklin examined why British mail ships were slower than merchant ships that sailed across the Atlantic Ocean. Franklin was serving as Deputy Postmaster General in the colonies, so he had a professional interest as well as scientific curiousity.

Franklin explored the question with his cousin Timothy Folger, a Nantucket ship captain with an understanding of ocean currents from personal experince and from discussions with American whalers. Franklin realized that merchant sea captains minimized the time they spent sailing within the Gulf Stream, while British ship captains responsible for carrying the mail ignored the current.

Franklin and Folger produced an accurate map documenting the location of the Gulf Stream. British mail ship captains reportedly ignored the information since it came from just a "colonial," but in the American Revolution French ship captains took advantage of the map.2

The Spanish understood the benefits of using the Gulf Stream long before the English. Ponce de Leon may have been the first to recognize and use it, in 1513. Throughout the 16th Century, Spanish treasure fleets sailed through the straights between Florida and the Bahamas, then north past Bermuda, because the current sped the journey eastward towards Seville.3

The Spanish treated their "Padron Real" and other maps as state secrets. As a result, Benjamin Franklin often gets credit for "discovering" the Gulf Stream that many Spanish pilots and ship captains had utilized effectively for over 150 years before Franklin and Folger published their map.4

Benjamin Franklin and his cousin Timothy Folger documented that sailing in the Gulf Stream could increase time required to cross the Atlantic Ocean to North America
Benjamin Franklin and his cousin Timothy Folger documented that sailing in the Gulf Stream could increase time required to cross the Atlantic Ocean to North America
Source: Library of Congress, Franklin-Folger chart of the Gulf Stream (Benjamin Franklin and Timothy Folger, c.1769-1770)

The flow of the Gulf Stream may lower sea level on Virginia's coastline, by pulling ocean water eastward and away from the edge of the continent. In 2015, Hurricane Joaquin slowed the speed of the Florida Current between Florida and the Bahamas. In Hampton Roads, without the Gulf Stream flowing at its normal speed, high tides were as much as 3 feet higher than predicted.5

Virginia and the Outer Continental Shelf (OCS)

Links

References

1. "A powerful current just miles from SC is changing. It could devastate the East Coast," Post and Courier (Charleston, South Carolina), September 5, 2018, https://www.postandcourier.com/news/special_reports/a-powerful-current-just-miles-from-sc-is-changing-it/article_7070df22-67fd-11e8-81ee-2fcab0fd4023.html (last checked September 11, 2018)
2. "Who first charted the Gulf Stream?," National Ocean Service, National Atmospheric and Oceanic Administration (NOAA), https://oceanservice.noaa.gov/facts/bfranklin.html; "This Old Map: Benjamin Franklin's Gulf Stream, 1786," CityLab, December 23, 2015, https://www.citylab.com/design/2015/12/this-old-map-benjamin-franklins-gulf-stream-1786/421740/; Philip L. Richardson, "Benjamin Franklin and Timothy Folger's First Printed Chart of the Gulf Stream," Science, New Series, Volume 207, Number 4431 (Feb. 8, 1980), https://www.jstor.org/stable/1683491 (last checked September 11, 2018)
3. Jerry Wilkinson, "History of the Gulf Stream," Historical Preservation Society of the Upper Keys, http://www.keyshistory.org/gulfstream.html (last checked September 11, 2018)
4. Elizabeth Horodowich, The Venetian Discovery of America: Geographic Imagination in the Age of Encounters, Cambridge University Press, 2018, p.101, https://books.google.com/books?id=vdloDwAAQBAJ (last checked September 13, 2018)
5. "Gulf Stream emerging as sea level rise "wild card" for Hampton Roads," The Virginian-Pilot, March 14, 2018, https://pilotonline.com/news/local/environment/article_64bc0598-23bb-11e8-9206-93c61594c171.html

ocean colors reveal how the Gulf Stream veers away from the continent at Cape Hatteras
ocean colors reveal how the Gulf Stream veers away from the continent at Cape Hatteras
Source: National Aeronautics and Space Administration (NASA) Visible Earth, Gulf Stream


Rivers and Watersheds of Virginia
Virginia Places