What was most surprising was the degree of change; even the most incremental differences in ocean temperatures matter.
(PRWEB UK) 28 June 2011
Data from Catlin Arctic Survey 2011, collected during an eight-week expedition from March to May, indicates the temperature of Arctic seawater below 200 metres depth has decreased by a 'surprising' one degree Celsius in comparison with previous observations.
This may conversely be accelerating the Arctic sea ice melt, which could have a knock-on effect for the currents that circulate heat and nutrients around the world's oceans.
Survey research partner Dr. Simon Boxall, of the National Oceanography Centre in Southampton, UK, says the temperature change indicates that melting sea ice in the Arctic is quickly circulating into the ocean’s depths and being replaced by warmer seawater from below.
While global ocean temperatures are rising, a layer of fresher water immediately beneath the Arctic sea ice is thought to act as buffer between the ice and warmer Atlantic waters flowing into the Arctic Ocean basin at a lower level.
The Arctic plays an important role in driving circulating ocean currents. Any change to the processes which sustain this system could impact weather patterns in Europe and the East Coast of North America.
Dr Boxall said: "So far, it appears we’re losing that 'buffer' layer of water, although more analysis of the data is needed over the coming months to better understand this process. The current data does show evidence of ‘mixing’ within the water column, which would further accelerate ice melt from the bottom up."
He continued: "What was most surprising was the degree of change; even the most incremental differences in ocean temperatures matter. To put this temperature change in context, global sea temperatures rose by only 0.25 of a degree Celsius in the last 30 to 40 years but this was enough for the IPCC’s Fourth Assessment Report to state the oceans are warming."
Dr. Boxall is currently undertaking full analysis of the expedition data and published findings are expected in 2012.
A four-person team of polar explorers from the UK, US and Australia skied, and where necessary swam, more than 300 miles/500 kilometres over 47 days to gather data on sea temperature, salinity and currents.
Forty profiles of temperature and salinity were taken from just below the ocean surface down to a depth of 300m (with one profile taken to a 500-metre depth). The speed and direction of current flow was measured at 20 metre intervals down to 80 meters in depth.
Pen Hadow, polar explorer and the Catlin Arctic Survey's director, said, "The scale of change in the water column and its connection to sea ice melt provides one possible answer to why Arctic ice loss has occurred so rapidly and unexpectedly. But these observations are proof, if any were needed, of how vital it is to continue on-the-ice research in the Arctic. These first indications about the sea ice will be followed by more detailed and extensive results from past Catlin Arctic Survey-enabled research, which will be published in the coming months."
Stephen Catlin, chief executive of Catlin Group Limited, which is the title sponsor of the Catlin Arctic Survey, said: "The early findings from this year's Catlin Arctic Survey show that the Arctic environment continues to change. These changes could have a profound impact on weather patterns in the rest of the world. We are anxiously awaiting the full analysis of the data to see what impact these changes could have on the earth’s population."