Solar activity linked to changes in ocean currents and climate

21 March 2014, by Tamera Jones

The sun and its activity

The findings mean an imminent quiet period in the Sun’s activity predicted by some scientists could lead to severe winters in Britain.

Researchers found that lower solar activity can drastically affect the climate in the North Atlantic, encouraging high pressure blocking systems to develop.

These blocking systems end up changing the course of prevailing westerly winds, stopping warm winds from the tropics getting to Europe. This leads to cold winters setting in, exactly like those of 2010 and 2013.

Researchers have linked low solar activity to the Little Ice Age before. But this is the first time anyone has shown how a drop in the Sun’s energy can lead to changes in the climate around the North Atlantic. The findings are published in Nature Geoscience.

‘Our study concludes that although the temperature changes expected from future solar activity are much smaller than the warming from human carbon dioxide emissions, regional climate variability associated with the effects of solar output on the ocean and atmosphere should be taken into account when making future climate projections,’ says Dr Paola Moffa-Sánchez of Cardiff University, who led the study.

The researchers used a sediment core taken from the ocean floor south of Iceland to investigate how the Gulf Stream differed from today. They did this by analysing the chemical composition of the shells of fossilised microorganism called foraminifera within the core.

Moffa-Sánchez and her colleagues looked in this region because the currents here, which are part of the surface waters of the so-called ocean conveyor belt, are important for the whole of the Earth’s climate.

The conveyor belt is a system of ocean currents, which move heat around in the world’s oceans. In the Atlantic Ocean, warm upper-ocean water travels north, to the high northern latitudes, where it loses heat to the atmosphere. It’s this process that keeps the UK relatively mild in winter compared to other countries at similar latitudes. This water cools then sinks and returns southwards at great depth.

‘We found big and abrupt changes in temperature and salt concentrations in the sediment core, which matched changes in solar activity,’ says Moffa-Sánchez.

‘Our measurements show that when solar activity was low, sea water south of Iceland was colder and fresher, rather than warm and salty. The ocean changes and the atmosphere probably both react to changes in the Sun’s energy output and develop feedbacks between the ocean and atmosphere. If you have a colder ocean current and a high pressure system during solar minima, the heat transport to Europe is going to be reduced leading to the cold spells recorded in Europe,’ she adds.

The researchers tested their results using a computer simulation of the climate and found exactly the same results.

Other scientists have suggested that higher levels of volcanic activity during the Little Ice Age led to colder winters. But Moffa-Sánchez separated the lower solar activity and volcanic activity in the climate model to test this idea.

They found that the Sun’s energy levels had a much bigger part to play in the climate during the last 1000 years than volcanic activity did.

‘When you see an increase in volcanism, this coincides with solar minima, so it’s hard to separate the two and say which contributed most to the ocean changes we record. But when we separated the volcanic activity and changes in the Sun¿s energy ouput in our model, we found that the Sun played a dominant role in the ocean and atmospheric changes over the last 1000 years,’ she explains.

This isn’t the first time scientists have linked the Sun’s energy output to high pressure blocking systems in the North Atlantic. Other studies have shown how solar activity affects UK winter temperatures. A period of low solar activity, called the Maunder Minimum, has been linked to cold temperatures in the so-called Central England Temperature record.

Keywords: Atlantic Ocean, Atmosphere, Climate system, Oceans, UK, Volcanoes, Weather,

Why this ad? 650% Investment Returns – todaysbestinvestments.com – Invest In Alternative Investments. Huge Profits. Free Top-Pick Guide!

Charlie Wood – 350.org Australia charlie@350.org	10:20 AM (5 minutes ago)
to me

Dear friend,

“The coal price required for many of these projects to be economic, is unlikely to be sustained…” – Caldecott, Tilbury & Ma (2013)*

Next week, this message will be signalled loud and clear, when Oxford University and Bloomberg New Energy Finance’s Ben Caldecott kicks off his tour of Australia. Click here to find out more.

While retirees, religious leaders, parents and young people put their bodies on the line to halt dangerous new fossil fuel projects, the financial case for moving beyond fossil fuels is growing by the day.

Come and hear Ben discuss the financial obstacles facing new Australian fossil fuel projects, discover how your money is funding these projects and learn how you can use your dollars and cents to secure a safe climate future. 

Click here to find your nearest event.**

Look forward to seeing you there!

Warm wishes,

Charlie on behalf of the 350.org Australia team

*Stranded Down Under: environment-related factors changing China’s demand for coal and what this means for Australian coal assets’

**Note the new venue if you are attending the Sydney event – this has changed due the original venue booking out within 2 days!

350.org is building a global climate movement.

Topics: Climate, climate forecast, el nino, ENSO, NOAA, oceans, sea surface

Arctic sea ice extent in February 2014 was the fourth lowest on record for the month and almost exactly in line with the long term trend decline while sea ice extent in the Antarctic remains significantly above average, according to data from the US National Snow and Ice Data Center (NSIDC).

Click to enlarge. Arctic sea ice extent for February 2014 was 14.44 million square kilometers (5.58 million square miles). The orange line shows the 1981 to 2010 median extent for that month. The black cross indicates the geographic North Pole. Courtesy: NSIDC.

Click to enlarge. The graph above shows Arctic sea ice extent as of March 3, 2014, along with daily ice extent data for five previous years. 2013-2014 is shown in blue, 2012-2013 in green, 2011-2012 in orange, 2010-2011 in brown, and 2009-2010 in purple. The 1981 to 2010 average is in dark gray. Courtesy: NSIDC.

Click to enlarge. Monthly February ice extent for 1979 to 2014 shows a decline of -3.0% per decade relative to the 1981 to 2010 average. Courtesy: NSIDC.

Click to enlarge. Barents Sea ice extent during February from the NSIDC Multisensor Analyzed Sea Ice Extent (MASIE) for the years 2010 through 2014. MASIE is produced daily by the U.S. National Snow and Ice Data Center based on human analysis of a variety of available satellite imagery. Courtesy: NSIDC.

Click to enlarge. Bering Sea ice extent during February from the NSIDC Multisensor Analyzed Sea Ice Extent (MASIE) for the years 2010 through 2014. MASIE is produced daily by the U.S. National Ice Center based on human analysis of a variety of available satellite imagery. Courtesy: NSIDC.

Click to enlarge. Antarctic sea ice extent (blue) compared with the previous Antarctic Summer (green). Courtesy: NSIDC.

Click to enlarge. Long term growth in the extent of Antarctic sea ice in February which shows a long term growth rate of 4.1 per cent. Courtesy: NSIDC.

Arctic sea ice extent continued to decline at a rate of around 3 per cent per decade in February 2014, while Antarctic sea ice extent continued to grow at a rate of around 4 per cent per decade, according to the latest NSIDC data.

Below is the monthly report published by the US National Snow and Ice Data Center (NSIDC). The top five images (right) were issued with the report. The bottom two images are also from NSIDC but they were not included with the report which does not mention Antarctic sea ice extent in February 2014.

In The Arctic, Winter’s Might Doesn’t Have Much Bite

While the eastern half of the United States has dealt with a cold and snowy winter, temperatures in the Arctic have been distinctly higher than average. The warm conditions have led to a slower than average expansion of the winter ice cover. Less ice also contributes to higher air temperatures by allowing transfer of heat from the relatively warmer ocean. The annual maximum in sea ice extent is expected to occur sometime this month.

Overview Of Conditions

Arctic sea ice extent in February 2014 averaged 14.44 million square kilometers (5.58 million square miles). This is the fourth lowest February ice extent in the satellite data record, and is 910,000 square kilometers (350,000 square miles) below the 1981 to 2010 average. The lowest February in the satellite record occurred in 2005.

Overall, sea ice grew slowly through the month of February. There were periods of declining ice, likely related to changes in ice motion. Bering Sea ice cover has been below average throughout winter, in contrast to the last several winters. Ice extent also remains below average in the Barents Sea and the Sea of Okhotsk, helping to keep the Arctic ice extent two standard deviations below the 1981 to 2010 average.

Conditions In Context

Ice extent increased at an average daily rate of 14,900 square kilometers (5,750 square miles) per day through the month of February. This is about 25% slower than the 1981 to 2010 February average rate of 20,300 square kilometers (7,840 square miles) per day. As the maximum extent approaches, the daily rate of ice extent growth is expected to slow.

While the eastern half of the U.S. has suffered through a cold and sometimes snowy winter, conditions in the Arctic have been warmer than average. The Arctic in winter is still a very cold place and temperatures at the 925 mb level in the central Arctic averaged -25 to -15 degrees Celsius (-13 to 5 degrees Fahrenheit); however, this was 4 to 8 degrees Celsius (7 to 14 degrees Fahrenheit) above average for the month. The Arctic Oscillation settled into a near-neutral mode for February after swinging from a strong positive mode in December to a negative mode in January.

February 2014 Compared To Previous Years

The sea ice extent trend through February 2014 is -3.0% per decade relative to the 1981 to 2010 average, a rate of -46,100 square kilometers (-17,800 square miles) per year. Unlike the summer, where ice loss has accelerated over the past decade, winter month trends have been fairly consistent.

The Two Bs Of The Arctic: Barents and Bering

The Barents Sea has experienced consistently low extents, particularly in winter, and this year has been no different. While the Barents and Kara seas normally have close to 2 million square kilometers (772,000 square miles) of ice in February, recent years have seen 500,000 square kilometers (193,000 square miles) of ice extent or lower. This year, the Kara Sea is near average, but the Barents Sea remains low (Figure 4a). Unlike other regions in the Arctic, longer records of Barents Sea ice extent exist from records of fishing, whaling, and other activities. A recent paper (Miles et al., 2013) examined these records, along with paleoproxy data, to examine extent over the past four hundred years. They found a 60- to 90-year cycle in Barents and Greenland seas ice extent related to the Atlantic Multidecadal Oscillation (AMO); the AMO is a basin-wide cycle of sea surface temperature variability similar to the El Niño and La Niña cycles in the Pacific, but varying over much longer periods. This research shows that in addition to the warming trend in the Arctic, some sea ice regions are likely also responding to natural climate variability.

In contrast to the Barents, the Bering Sea ice has had higher than average extent in recent years. However this year is different; Bering Sea ice extent has been below average through much of the winter. During mid-February, extent increased to a higher level, as seen in Multisensor Analyzed Sea Ice Extent (MASIE) data (Figure 4b), before a slight decline at the end of the month. This is in contrast with recent years in the Bering that have seen very high extents, even record levels .

The Bering Sea consists exclusively of seasonal ice with a large marginal ice zone where new, thin ice dominates. Sea ice in this region is quite sensitive to changes in temperatures and, particularly, winds. Cold winds from the north advect ice southward and aid new ice growth. Warm winds from the south impede ice growth and push the ice northward, reducing extent in the region. Recent winters have been characterized by predominantly north winds. This year represents a change with more zonal, east to west, winds in January and February. As with the Barents Sea, the Bering may be responding to climate variability, including the Pacific Decadal Oscillation, though the links are complex (Bond et al., 2003).

Winter and spring ice in the Bering Sea is of high importance to people living in the region, such as walrus hunters who go out on the ice or in boats during spring and early summer. Because ice conditions are so important, analyses and forecasts, such as those provided by the SEARCH Sea Ice for Walrus Outlook (SIWO), are particularly valuable. The SIWO program begins reporting on sea ice in late March or early April and continues through late June. The site provides sea ice imagery and analysis, reports from hunters in the field, and forecasts of future conditions. These reports are important for hunters to plan hunts and safely traverse the ice-infested waters.

Source