Harry Bryden | |
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Born | Harry Leonard Bryden 9 July 1946 Providence, Rhode Island, United States of America |
Nationality | American, British |
Alma mater | Dartmouth College, Massachusetts Institute of Technology-Woods Hole Oceanographic Institution |
Known for | Thermohaline circulation |
Awards |
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Scientific career | |
Fields | Physical oceanographer |
Institutions | Oregon State University (OSU), Woods Hole Oceanographic Institution (WHOI), National Institute of Oceanography (NIO), National Oceanography Centre, Southampton (NOCS) |
Doctoral advisor | Nick Fofonoff |
Website | www |
Harry Leonard Bryden, FRS (born 9 July 1946) is an American physical oceanographer, professor at University of Southampton, [1] and staff at the National Oceanography Centre, Southampton. [2] He is best known for his work in ocean circulation and in the role of the ocean in the Earth's climate. [3]
Born in Providence, Rhode Island in 1946, Bryden received his A.B. degree in mathematics from Dartmouth College. For a short period after graduation, he worked as a mathematician on oceanographic topics for offices of the United States Navy in Maryland and Connecticut. Bryden's doctoral training in oceanography was undertaken at the Massachusetts Institute of Technology (MIT) and the Woods Hole Oceanographic Institution (WHOI) through the long-standing joint program for students that operates between these institutes. [4] During his time at MIT-WHOI, Bryden completed and published work on a number of topics including water mass properties, [5] Mediterranean outflow [6] and geostrophy. [7] He was supervised initially by Henry Stommel and then principally by Nick Fofonoff, and his thesis title was "Momentum, Mass, Heat, and Vorticity Balances from Oceanic Measurements of Current and Temperature". [8]
Upon competing his doctoral thesis, Bryden briefly moved to Oregon State University to work as a post-doctoral researcher, before returning to WHOI in 1977. He was awarded tenure at WHOI in 1983, and remained there until 1992, ultimately reaching the position of Senior Scientist. Bryden then moved to the United Kingdom and the Institute of Oceanographic Sciences (IOS), a unit funded by the Natural Environment Research Council (NERC). He moved with IOS to Southampton when it partnered with the University of Southampton to create the Southampton Oceanography Centre, and has remained with its successor institutes. Though partially retired, Bryden remains active at the University of Southampton in both research and the wider scientific community. Harry Bryden was appointed Regius Professor of Ocean Sciences at the University of Southampton in March 2020.
A particular focus of Bryden's research is the large-scale thermohaline circulation of the ocean, in particular its role in transporting heat. [9] [10] A decline in the strength of the Atlantic Meridional Overturning Circulation (AMOC) caused by global warming has been hypothesised, and Bryden and colleagues have studied this via the RAPID array [11] that crosses the Atlantic at 26.5°N. [12] [13]
In 2003, Bryden both became a Fellow of the American Meteorological Society, and was awarded the society's Henry Stommel Research Award "for fundamental and elegant observational contributions to understanding the oceanic general circulation". In 2005, Bryden was elected a Fellow of the Royal Society. [14] In 2009, he won the Prince Albert I Medal "in recognition of his fundamental contributions to understanding the ocean's role in the global climate system". [15] In 2010, Bryden was elected a Fellow of the American Geophysical Union. [16] Bryden served as president of the Challenger Society for Marine Science from 2010 to 2012. In late 2012, the European Geosciences Union awarded Bryden the 2013 Fridtjof Nansen Medal for his contributions to Earth sciences. [17] In 2013, in recognition of his work, Bryden was elected an Honorary Fellow of the Royal Meteorological Society (RMetS). [18]
The Drake Passage is the body of water between South America's Cape Horn, Chile, Argentina, and the South Shetland Islands of Antarctica. It connects the southwestern part of the Atlantic Ocean with the southeastern part of the Pacific Ocean and extends into the Southern Ocean. The passage is named after the 16th-century English explorer and privateer Sir Francis Drake.
An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, shoreline configurations, and interactions with other currents influence a current's direction and strength. Ocean currents move both horizontally, on scales that can span entire oceans, as well as vertically, with vertical currents playing an important role in the movement of nutrients and gases, such as carbon dioxide, between the surface and the deep ocean.
Thermohaline circulation (THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. The adjective thermohaline derives from thermo- referring to temperature and -haline referring to salt content, factors which together determine the density of sea water. Wind-driven surface currents travel polewards from the equatorial Atlantic Ocean, cooling en route, and eventually sinking at high latitudes. This dense water then flows into the ocean basins. While the bulk of it upwells in the Southern Ocean, the oldest waters upwell in the North Pacific. Extensive mixing therefore takes place between the ocean basins, reducing differences between them and making the Earth's oceans a global system. The water in these circuits transport both energy and mass around the globe. As such, the state of the circulation has a large impact on the climate of the Earth.
In oceanography, a gyre is any large system of ocean surface currents moving in a circular fashion driven by wind movements. Gyres are caused by the Coriolis effect; planetary vorticity, horizontal friction and vertical friction determine the circulatory patterns from the wind stress curl (torque).
The Walker circulation, also known as the Walker cell, is a conceptual model of the air flow in the tropics in the lower atmosphere (troposphere). According to this model, parcels of air follow a closed circulation in the zonal and vertical directions. This circulation, which is roughly consistent with observations, is caused by differences in heat distribution between ocean and land. In addition to motions in the zonal and vertical direction the tropical atmosphere also has considerable motion in the meridional direction as part of, for example, the Hadley Circulation.
The Sverdrup balance, or Sverdrup relation, is a theoretical relationship between the wind stress exerted on the surface of the open ocean and the vertically integrated meridional (north-south) transport of ocean water.
Henry Melson Stommel was a major contributor to the field of physical oceanography. Beginning in the 1940s, he advanced theories about global ocean circulation patterns and the behavior of the Gulf Stream that form the basis of physical oceanography today. Widely recognized as one of the most influential and productive oceanographers of his time, Stommel was both a groundbreaking theoretician and an astute, seagoing observer.
The Atlantic meridional overturning circulation (AMOC) is the main ocean current system in the Atlantic Ocean. It is a component of Earth's ocean circulation system and plays an important role in the climate system. The AMOC includes Atlantic currents at the surface and at great depths that are driven by changes in weather, temperature and salinity. Those currents comprise half of the global thermohaline circulation that includes the flow of major ocean currents, the other half being the Southern Ocean overturning circulation.
The World Ocean Circulation Experiment (WOCE) was a component of the international World Climate Research Program, and aimed to establish the role of the World Ocean in the Earth's climate system. WOCE's field phase ran between 1990 and 1998, and was followed by an analysis and modeling phase that ran until 2002. When the WOCE was conceived, there were three main motivations for its creation. The first of these is the inadequate coverage of the World Ocean, specifically in the Southern Hemisphere. Data was also much more sparse during the winter months than the summer months, and there was—and still is to some extent—a critical need for data covering all seasons. Secondly, the data that did exist was not initially collected for studying ocean circulation and was not well suited for model comparison. Lastly, there were concerns involving the accuracy and reliability of some measurements. The WOCE was meant to address these problems by providing new data collected in ways designed to "meet the needs of global circulation models for climate prediction."
Boundary currents are ocean currents with dynamics determined by the presence of a coastline, and fall into two distinct categories: western boundary currents and eastern boundary currents.
John Crossley Swallow FRS was an English oceanographer who invented the Swallow float, a scientific drifting bottle based on the messages in bottles that shipwrecked sailors hoped would reach inhabited shores, summoning assistance.
The Gulf Stream is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the United States, then veers east near 36°N latitude and moves toward Northwest Europe as the North Atlantic Current. The process of western intensification causes the Gulf Stream to be a northward-accelerating current off the east coast of North America. Around 40°0′N30°0′W, it splits in two, with the northern stream, the North Atlantic Drift, crossing to Northern Europe and the southern stream, the Canary Current, recirculating off West Africa.
Michael John Robert Fasham, FRS was a British oceanographer and ecosystem modeller. He is best known for his pioneering work in the development of open ocean plankton ecosystem models.
Mode water is defined as a particular type of water mass, which is nearly vertically homogeneous. Its vertical homogeneity is caused by the deep vertical convection in winter. The first term to describe this phenomenon is 18° water, which was used by Valentine Worthington to describe the isothermal layer in the northern Sargasso Sea cooling to a temperature of about 18 °C each winter. Then Masuzawa introduced the subtropical mode water concept to describe the thick layer of temperature 16–18 °C in the northwestern North Pacific subtropical gyre, on the southern side of the Kuroshio Extension. The terminology mode water was extended to the thick near-surface layer north of the Subantarctic Front by McCartney, who identified and mapped the properties of the Subantarctic mode water (SAMW). After that, McCartney and Talley then applied the term subpolar mode water (SPMW) to the thick near-surface mixed layers in the North Atlantic’s subpolar gyre.
The cold blob in the North Atlantic describes a cold temperature anomaly of ocean surface waters, affecting the Atlantic Meridional Overturning Circulation (AMOC) which is part of the thermohaline circulation, possibly related to global warming-induced melting of the Greenland ice sheet.
Amy Bower is an American physical oceanographer at Woods Hole Oceanographic Institution. She is known for her research on ocean circulation and for being one of the few blind oceanographers.
The Atlantic meridional overturning circulation (AMOC) is a large system of ocean currents, like a conveyor belt. It is driven by differences in temperature and salt content and it is an important component of the climate system. However, the AMOC is not a static feature of global circulation. It is sensitive to changes in temperature, salinity and atmospheric forcings. Climate reconstructions from δ18O proxies from Greenland reveal an abrupt transition in global temperature about every 1470 years. These changes may be due to changes in ocean circulation, which suggests that there are two equilibria possible in the AMOC. Stommel made a two-box model in 1961 which showed two different states of the AMOC are possible on a single hemisphere. Stommel’s result with an ocean box model has initiated studies using three dimensional ocean circulation models, confirming the existence of multiple equilibria in the AMOC.
Jean Lynch-Stieglitz is a paleoceanographer known for her research on reconstructing changes in ocean circulation over the last 100,000 years.
Lisa M. Beal is a professor at the University of Miami known for her work on the Agulhas Current. She is the editor-in-chief of the Journal of Geophysical Research: Oceans.
Laure E. Zanna is a Climate Scientist and Professor in Mathematics & Atmosphere/Ocean Science at the Courant Institute of Mathematical Sciences, New York University. She works on topics including climate system dynamics, the influence of the oceans on global scales, data science, and machine learning. In July 2019 she was awarded the Nicholas P. Fofonoff Award for Early Career Research by the American Meteorological Society for "exceptional creativity in the development and application of new concepts in ocean and climate dynamics." She is the lead principal investigator of the NSF-NOAA Climate Process Team on Ocean Transport and Eddy Energy, and she is also the lead investigator of an international effort to improve climate models with scientific machine learning called M2LInES.