Dramatic Change In Ocean Salinity And A Wetter North
11 September, 2012
The high-latitude North is becoming wetter while there is dramatic change in the oceans' salt content. The salty parts of the oceans have turned saltier and the fresh regions have become fresher. The degree of change, over the past 50 years, is greater than scientists can explain.
Researchers are heading out into one particularly salty ocean region, in the middle of the North Atlantic Ocean to know the reason behind variation in salinity in the upper ocean.
Many oceanographers have a hunch about what is going on: Climate change, Ray Schmitt, a senior scientist at the Woods Hole Oceanographic Institution, told journalists during a news conference on Sept. 5.
Schmitt said: "The 50-year trend […], most of us believe is really due to the general trend of global warming."
This matters because the ocean is at the heart of the planet's water cycle: 86 percent of global evaporation and 78 percent of global precipitation occur over the ocean, according to NASA, the lead entity behind the project Salinity Processes in the Upper Ocean Regional Study (SPURS).
Over the ocean, more evaporation as compared to precipitation translates into saltier water. Meanwhile, in regions where precipitation is favored, water is fresher.
By tracking ocean salinity, researchers can better understand the global water cycle. Global warming is expected to intensify it, but current computer models do not predict the amount of change seen over the last 50 years, Schmitt said.
Aside from an increase in evaporation caused by warming, such factors as winds can also contribute to changes in salinity.
The mid-Atlantic isn't the only area where researchers hope to study ocean salinity in detail. Researchers hope to do something similar in a low-salinity region, such as the Bay of Bengal or an area south of Hawaii .
While researchers think global climate change may be behind the changes in ocean salinity, changes like these are expected to have their own implications for climate. Ocean salinity also affects ocean circulation, and as a result, ocean temperatures having implications for weather.
Compared with fresh water, salty water is heavier, and so more prone to sinking. Temperature has a similar effect, with warmth causing water to rise. Differences in salinity and temperature drive a slow-moving conveyor belt of ocean currents that encircles the planet. The Gulf Stream , which carries warm water across the Atlantic to Europe , is part of this conveyor belt.
It may work out that higher salinity in some regions counterbalances fresher water in others, Schmitt said: "It is a delicate balance and what we think now is it is not too likely the conveyer belt is going to shut down anytime soon."Wetter Arctic
Ob , Lena and Yenesei rivers are dumping more fresh water into the Arctic Ocean per year than they did in the 1940s. Increased precipitation and river discharge in the Arctic has the potential to speed climate change. Citing results of a study led by Xiangdong Zhang, scientist at the University of Alaska , Fairbanks , International Arctic Research Center , ScienceDaily reported  the Arctic news on Sept. 5, 2012 .
"As the Earth's climate continues to change, the high-latitude North is becoming even wetter than before," Zhang says. "In particular, air moisture, precipitation and river discharge have increased, leading to a stronger water cycle. These recent changes may intensify climate system interactions and further advance climate change."
The news said:
Zhang and his co-authors including IARC colleague Igor Polyakov looked at water cycles in the Ob, Lena and Yenesei River drainages in the Eurasian Arctic during the last six decades. They found atmospheric moisture into the areas increased by an average of 2.6 percent per decade and, consequently, river discharge increased at a rate of nearly 2 percent per decade. That means the three rivers today are dumping almost 39 cubic miles more fresh water into the Arctic Ocean per year than they did in the 1940s.
Their findings are important because studies have suggested that increased air moisture and precipitation, and the resulting increase in river discharge into the Arctic Ocean , can lower salinity and cause warmer surface temperatures, as well as create weaker water circulation in the Atlantic Ocean . Those things in turn can affect multiple biological and weather systems, as well as things like sea ice and coastal erosion.
The study results were published in the journal Nature Climate Change . The paper, "Enhanced poleward moisture transport and amplified northern high-latitude wetting trend," (Xiangdong Zhang, Juanxiong He, Jing Zhang, Igor Polyakov, Rüdiger Gerdes, Jun Inoue, Peili Wu. Enhanced poleward moisture transport and amplified northern high-latitude wetting trend. Nature Climate Change, 2012; DOI: 10.1038/nclimate1631, University of Alaska Fairbanks) suggests that in addition to changes in local processes such as thawing permafrost and decreasing transpiration by plants, this intensified water cycle also depends heavily on changes in large-scale atmospheric dynamics.Rocky Mountains affect Norway 's climate
The Rocky Mountains , the Gulf Stream and the Norwegian Sea play a major role in weather in Norway . In another report  on Sep. 6, 2012 ScienceDaily said:
The Gulf Stream and the Norwegian Sea have a major impact on Norway 's climate. Weather conditions are influenced by geographical elements from much farther away.
Researchers can now study climate in ways impossible just a few years ago. One can see the simulated outcome of "removing" major mountain ranges known to influence climate.
Researchers at the Bjerknes Centre for Climate Research in Bergen removed the Rocky Mountains of western North America from their simulation program, and they were surprised to discover the extent to which this distant mountain range affected Norway 's climate.
Because of the Rocky Mountains , enormous air masses from the west are forced more southward, where they absorb heat and moisture before heading in Norway 's direction. In this way, the mountain range helps to create the dominant southwesterly winds that bring so much warm, moist air towards Norway .
Primarily, because of these winds that most of Norway has an annual mean temperature well above the freezing point. This is 5°C to 10°C warmer than the annual mean temperatures at the same latitude around Earth.
 [The original article was written by Bård Amundsen and Else Lie. The translation is by Darren McKellep and Victoria Coleman.]
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