(a) Temperature section at 24° N in the Atlantic from the 2010 hydrographic cruise on the RRS Discovery. Black vertical lines indicate locations of moorings from the RAPID array. (b) Overturning transport estimated from five hydrographic sections in 1957, 1981, 1992, 1998 and 2004 (red, solid). Red dashed shows the transports from the hydrographic section corrected for the seasonal cycle of the MOC, as estimated from RAPID (2004–2007). Note the amplitude of the long-term decrease from 1957 to 2004 is reduced once aliasing of the seasonal cycle is accounted for. (Online version in colour.)
Abstract
Sustained observations of ocean properties reveal a global warming trend and rising sea levels. These changes have been documented by traditional ship-based measurements of ocean properties, whereas more recent Argo profiling floats and satellite records permit estimates of ocean changes on a near real-time basis. Through these and newer methods of observing the oceans, scientists are moving from quantifying the ‘state of the ocean’ to monitoring its variability, and distinguishing the physical processes bringing signals of change. In this paper, I give a brief overview of the UK contributions to the physical oceanographic observations, and the role they have played in the wider global observing systems. While temperature and salinity are the primary measurements of physical oceanography, new transbasin mooring arrays also resolve changes in ocean circulation on daily timescales. Emerging technologies permit routine observations at higher-than-ever spatial resolutions. Following this, I then give a personal perspective on the future of sustained observations. New measurement techniques promise exciting discoveries concerning the role of smaller scales and boundary processes in setting the large-scale ocean circulation and the ocean’s role in climate. The challenges now facing the scientific community include sustaining critical observations in the case of funding system changes or shifts in government priorities. These long records will enable a determination of the role and response of the ocean to climate change.
Eleanor Frajka-Williams
Professor of Ocean Dynamics in a Changing Climate
I am a physical oceanographer who uses ocean observations to investigate ocean dynamics and circulation in a changing climate. I have a particular interest in problems spanning scales (from micro- to large-scale) or spheres (biogeosphere, cryosphere, atmosphere), and in methods that leverage traditional observations with new platforms and satellite data.