Physical Oceanography

Physical oceanography – one of the four main branches of oceanography[1] – involves studying the properties (such as temperature and density) and movement (such as waves, currents, and tides) of ocean water.[2] It also involves studying the interaction between the ocean and the Earth’s atmosphere, how the ocean stores and releases heat, and coastal dynamics. [3] Stated another way, physical oceanographers study the interaction between the ocean and its boundaries — land, seafloor, and atmosphere — and the relationship between the sea, weather, and climate. [4]

Physical oceanography is divided into descriptive and dynamical physical oceanography. Descriptive physical oceanography “approaches the ocean through both observations and complex numerical model output used to describe the fluid motions as quantitatively as possible.”[5] Dynamical physical oceanography “seeks to understand the processes that govern the fluid motions in the ocean mainly through theoretical studies and process-based numerical model experiments.”[6]

Clearly, physical oceanography is serious business – not only in terms of the scope and rigor of the academic subject matter that needs to be mastered (physics, mathematics, chemistry, computer science, statistics, data analysis, etc.) but also the pressing nature of the types of areas researched (climate change, greenhouse gasses, extreme sea-level events).

Like all of the main branches of oceanography, physical oceanography covers a lot of territory. Research carried out by physical oceanographers ranges from the microscopic to the global, from the coastline to the deep ocean, and from the ocean floor to the atmosphere.[7] In fact, it might just be easier to list the areas it doesn’t cover.

And because it covers such a wide range of academic, geographic, and physical areas, it is difficult to provide a “brief” overview of physical oceanography. However, by looking at some broad areas of research addressed by physical oceanography and the skill set needed (together with citations and links to the relevant website in case you want to learn more), a clearer picture emerges of this critical area of oceanography.

Ocean Cycles and Climate Change

Physical oceanographers study large-scale physical and biological cycles in the ocean. They analyze how climate-driven changes in upwelling, ocean mixing, oxygen minimum zones, and nutrient cycling affect the year-to-year variation in ocean ecosystem processes.[8]

Ocean Circulation and Algae Blooms

Physical oceanographers study how changes in ocean circulation affect populations of microscopic marine algae. [9] They make extensive use of satellites, autonomous underwater vehicles, and other state-of-the-art tools.[10]

Sea Level and Ocean Climate

Physical oceanographers develop computer models of tides and storm surges to deliver improved forecasting systems for coastal flooding and sea-level extreme events. Physical oceanographers combine geodetic observations of sea level (using tide gauges and satellite altimetry), ocean mass changes and vertical land movement, with theoretical and modeling expertise of solid Earth, ocean, and climate dynamics.[11]

Polar Oceanography

Physical oceanographers “study the physical mechanisms responsible for the distribution of sea ice and polar ice sheets, the circulation of high-latitude oceans, and the interactions between the atmosphere, ocean and cryosphere that play an important role in regulating Earth’s climate.”[12]

Satellite Oceanography

In order to help improve predictions of marine systems’ reactions to climate change, physical oceanographers measure exchanges between the atmosphere, ocean, marine biosphere, and coastal zones.[13]

Coastal Ocean and Estuarine Processes

Physical oceanographers study the processes and basic interactions operating on the continental shelf, from the coast up to and including the shelf break. These marine areas are affected by polluted runoff and sewage, overfishing and climate change more rapidly and extensively than the deep sea.[14] By developing comprehensive models of the physics, chemistry and biology of shelf seas, physical oceanographers are able to predict the impacts of climate change.[15]

Surface and Subsurface Currents

Physical oceanographers use observations from surface drifting buoys, Argo floats, and satellite altimetry to estimate and understand the variability of surface and subsurface currents.[16]

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Citations

1. The others are biological oceanography, chemical oceanography, and geological oceanography.
2. Oceanography, Texas A&M University.
3. Physical Ocean, NASA Science, Share the Science.
4. A Sea Grant Guide to Ocean Opportunities.
5. Descriptive Physical Oceanography: An Introduction, Talley, Lynne D. (2011).
6. Descriptive Physical Oceanography: An Introduction, Talley, Lynne D. (2011).
7. Marine Physics and Ocean Climate, National Oceanography Centre.
8. Monterey Bay Aquarium Research Institute.
9. Monterey Bay Aquarium Research Institute.
10. Monterey Bay Aquarium Research Institute.
11. Marine Physics and Ocean Climate, National Oceanography Centre.
12. School of Oceanography, University of Washington.
13. Marine Physics and Ocean Climate, National Oceanography Centre.
14. School of Oceanography, University of Washington.
15. Marine Physics and Ocean Climate, National Oceanography Centre.
16. Physical Oceanography Division, NOAA.