When the warm water reaches the continental shelves, it peels off in northerly and southerly directions, travelling along the shelf-line towards the poles. According to scientists at Plymouth University’s Marine Institute and the National Centre for Scientific Research (CNRS), many of the pulses coincide with El Niño events – and their heat content is increasing in intensity. The lead author of the report, Professor Philip Reid, of the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) and the Marine Institute, said the global mechanism provided an explanation for the timing and connection of a wide-range of observed hydrographic, ecosystem and cryospheric (frozen ice/snow) events.
He said: “We have described for the first time a globally synchronous pattern of pulsed, short-term (one year) emanations of warm temperatures that pass along continental shelves, from tropical seas to the poles. “Warm tropical waters appear to be acting like a heart, accumulating heat and energy, and then pumping it in bursts that progressively move toward the poles, a process that seems to be accelerating.”
Reid and research partner Dr Gregory Beaugrand mapped and statistically analysed average temperatures for every two-degree square of latitude and longitude, from 1960 until 2008 for the whole global ocean, with a finer single degree resolution along continental shelves. They found a remarkable degree of symmetry, both north and south of the equator, and very clear spikes in the temperature followed by a period of cooling. Co-author of the report Dr Beaugrand said: "We found sudden increases in temperatures in 1976, 1987, 1998, and throughout the first decade of the new millennium that coincided with well-documented ecosystem changes."...
The Indian Ocean Gyre, rendered by Jack, public domain
No comments:
Post a Comment