Brief History of Oceanography

The focus of this article and this book is on the two branches of oceanography that deal with

• Physical oceanography, or marine physics, that studies the ocean's physical attributes including temperature-salinity structure, mixing, waves, internal waves, surface tides, internal tides, and currents, acoustical and optical oceanography;

• and, to some extent, biogeochemical oceanography which involves the scientific study of the chemical, physical, geological, and biological processes and reactions that govern the composition of the natural environment, and the cycles of

Centre for Australian Weather and Climate Research—A partnership between CSIRO and the Bureau of Meteorology; CSIRO Wealth from Oceans National Research Flagship, Hobart, Tasmania, Australia.

CSIRO Marine and Atmospheric Research, Castray Esplanade, GPO Box 1538, Hobart 7001, Tasmania, Australia e-mail: [email protected]

A. Schiller, G. B. Brassington (eds.), Operational Oceanography in the 21st Century, DOI 10.1007/978-94-007-0332-2_1, © Springer Science+Business Media B.V. 2011

matter and energy that transport the Earth's chemical components in time and space. Biogeochemical oceanography focuses on chemical cycles which are either driven by or have an impact on biological activity such as carbon, nitrogen, and phosphorus cycles.

We first describe briefly the general history that laid the foundation of ocean forecasting. The focus here is not on a comprehensive description of the whole science of oceanography but to focus on those components that are underpinning today's ocean forecasting systems, in particular the development of an ocean observing system and hydrodynamic numerical modelling.

Man first began to acquire knowledge of the waves, tides and currents of the seas and oceans in pre-historic times. During The Age of Discovery (approximately late 1400s to early 1700s) exploration of the oceans was primarily for cartography and mainly limited to its surfaces, although depth soundings were taken by lead line.

During the beginning of the scientific voyages (late 1700s to twentieth century) in 1769 Benjamin Franklin published one of the earliest maps of the Gulf Stream (Fig. 1.1).

Fig. 1.1 Map of the Gulf Stream created by Benjamin Franklin. The Gulf Stream is depicted as the dark gray swath that runs along the east coast of what is now the United States. (Franklin 1769, Courtesy NOAA Photo Library)

One of the most famous voyages of discovery of this time began in 1768 when HMS Endeavour left Portsmouth, England, under the command of Captain James Cook. Over 10 years Cook led three world-encircling expeditions and mapped many countries, including Australia, New Zealand and the Hawaiian Islands. He was an expert seaman, navigator and scientist who made observations wherever he went.

James Rennell and John Purdy wrote the first scientific textbooks about currents in the Atlantic and Indian oceans during the late eighteenth and at the beginning of the nineteenth century (e.g. Rennell and Purdy 1832).

The steep slope beyond the continental shelves was not discovered until 1849. Matthew Fontaine Maury's Physical Geography of the Sea (Fig. 1.2) was the first textbook of oceanography based on his work as superintendant of the Depot of Charts and Instruments of the Navy Department in Washington D.C. (Maury 1855).

Fig. 1.2 Matthew Maury: "The Physical Geography of the Sea," which is credited as "the first textbook of modern oceanography." (Maury 1855)

Fig. 1.2 Matthew Maury: "The Physical Geography of the Sea," which is credited as "the first textbook of modern oceanography." (Maury 1855)

Fig. 1.3 Ocean surface currents around Australia from Black and Hall's Atlas of the World published by A. & C. Black, Edinburgh (1865)

The first comprehensive maps that showed the surface circulation of the global oceans with reasonable accuracy were published by A. and C. Black in 1865 (Fig. 1.3).

In 1871, under the recommendations of the Royal Society of London, the British government sponsored an expedition to explore the world's oceans and conduct scientific investigations. Modern oceanography began with the Challenger Expedition between 1872 and 1876, when Charles Wyville Thompson and Sir John Murray launched the Challenger Expedition. It was the first expedition organized specifically to gather data on a wide range of ocean features, including ocean temperatures, seawater chemistry, currents, marine life, and the geology of the seafloor. They took water samples and temperature measurements, recorded currents and barometric pressures and collected bottom samples. The results of this expedition were published in 50 volumes covering biological, physical and geological aspects (Thompson et al. 1880-1895).

In 1893 Norwegian scientist Fridtjof Nansen allowed his ship Fram to be frozen in the Arctic ice. As a result he was able to collect valuable oceanographic, magnetic, and meteorological information in the Arctic. The rest of his career was equally as distinguished including the invention of a water-sampling bottle that permitted isolation of water samples from various depths to measure temperature, salinity and other parameters.

Other European and American nations also sent out scientific expeditions (as did private individuals and institutions). The first purpose-built oceanographic ship, the Albatros was built in 1882. The four-month 1910 North Atlantic expedition headed by Sir John Murray and Johan Hjort was at that time the most ambitious research oceanographic and marine zoological project ever, and led to the classic book The Depths of the Ocean (Murray and Hjort 1912).

At the beginning of the Age of Modern Oceanography (1900s to mid twentieth century) the first acoustic measurement of sea depth was made in 1914. Between 1925 and 1927 the Meteor expedition surveyed the Mid-Atlantic Ridge and gathered 70,000 ocean depth measurements using an echo sounder.

Virtually all civilian ocean research ceased in 1939 with the outbreak of World War II, when scientific resources were mobilised. However, many advances were made in instrumentation, and our understanding of the ocean was greatly improved. For example, there were major advances in predicting wave conditions (important for amphibious invasions). Mapping features of ocean basins was greatly expanded to improve the ability to detect submarines.

In 1942, Sverdrup et al. (1942) published The Ocean which was a major landmark in oceanography.

The nineteenth and twentieth century also saw major progress towards quantitative descriptions of observed phenomena. Examples of key areas of progress are (some of which are tightly linked to progress in meteorology):

• the rotation of the Earth and associated impact on ocean currents (Coriolis 1835);

• the effect of winds on the ocean-atmosphere interface (Ekman 1905); and

• the development of vorticity theories and theorems for the ocean as an extension to Newton's law in a rotating fluid (Ertel 1942; Sverdrup 1947).

This enhanced capability to describe the ocean within a mathematical framework allowed the development of numerical models. Consequently, from the 1970s onwards there has been increased emphasis on the application of computers for oceanography to allow numerical simulations and predictions of the state of the ocean.

The Mid-Ocean Dynamics Experiment (MODE) was one of the first large-scale and extensively instrumented field experiments carried out by physical oceanog-raphers. Conducted in two phases between November 1971 and July 1973, the experiment explored the role of mesoscale eddy motions in the dynamics of general oceanic circulation (mesoscale eddies are at the centre of attention in today's large-scale ocean forecasting systems).

The 1970s and 1980s also saw the development and first applications of so-called inverse methods to oceanographic data (e.g. Wunsch 1978). These methods can be interpreted as simple data assimilation tools that paved the way for the development of more complex data assimilation and model initialization tools used nowadays in ocean forecasting systems and often derived from numerical weather prediction applications.

The Tropical-Ocean-Global-Atmosphere (TOGA) Program began in 1985 and was a ten-year research effort to investigate the global atmospheric response to the coupled ocean-atmosphere forcing from the tropical regions. It was among the first large-scale programs that addressed the predictability of the coupled tropical oceans and global atmosphere by drawing on observations and by recognizing the key role of models for understanding tropical air-sea interactions as a prerequisite for launching successful climate predictions into the future.

In the 1980s the TAO/TRITON oceanographic buoy array was established in the Pacific to allow monitoring and ultimately prediction of El Niño events (http:// www.pmel.noaa.gov/tao/proj_over/taohis.html). Enhancements to the in situ and satellite observing system together with the first evolving model lead to the first successful ENSO prediction (Zebiak and Cane 1987).

1990 saw the start of the World Ocean Circulation Experiment (WOCE) which continued until 2002. 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. The WOCE field phase ran between 1990 and 1998 (Fig. 1.4), and was followed by an analysis and modelling phase that ran until 2002. The results are summarised in "Ocean Circulation and Climate: Observing and Modelling the Global Ocean" (Siedler et al. 2001).

Before the 1980s, when satellites became more commonly available, oceanogra-phers were "data poor". Since then, significant technological and scientific advances in satellite remote sensing provide near-real time measurements of sea surface height anomalies, SST and ocean colour. These key observations have, for the first time, enabled ocean forecasting applications (Fu and Cazenave 2001).

The realisation of the network of 3,000 Argo profiling floats freely reporting temperature and salinity profiles to 2,000 m depth in a timely fashion has transformed the in situ ocean measurement network in the new millennia (Fig. 1.5). This allows, for the first time, continuous monitoring of the temperature, salinity, and velocity of the upper ocean, with all data being relayed and made publicly available within hours after collection.

Based on significant advances in supercomputing technologies, the 1990s saw the emergence of the first large-scale eddy-resolving models (Semtner and Chervin 1992) and the first ocean-atmosphere coupled climate change projections (see, e.g. IPCC First Assessment Report 1990).

More detailed accounts of the history of oceanography can be found in the published literature and, e.g. at http://core.ecu.edu/geology/woods/HISTOCEA.htm.

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