Showing posts with label weather. Show all posts
Showing posts with label weather. Show all posts

Monday 28 December 2015

2015 warmest year on record

1.1°C or 34.1°F at the North Pole
The year 2015 is shaping up to be the warmest year on record. In the media, a lot of attention has been given to the many floods, droughts, wildfires and heatwaves that have battered the world this year.

Sadly, though, little attention is given to the situation in the Arctic. The image on the right shows a forecast for December 30, 2015, with temperatures at the North Pole above freezing point, as further illustrated by the nullschool.net image below, showing a temperature forecast of 1.1°C or 34.1°F for the North Pole. Wind speed at the North Pole is forecast to be 105 mph or 168 km/h on December 30, 2015, and 133 mph or 215 km/h closer to Svalbard.


As the image below illustrates, very high temperatures are forecast to hit the Arctic Ocean on December 30, 2015.


Above image shows temperature anomalies at the highest end of the scale for most of the Arctic Ocean, with a temperature anomaly for the Arctic as a whole of 2.4°C or 4.32°F above what was common in 1979-2000. The situation isn't likely to improve soon. For January 3, 2016, the temperature in the Arctic is forecast to be as much as 4.56°C or 8.21°F warmer.

How is it possible for such high temperatures to occur over the Arctic Ocean? The image below shows how the year 2015 is shaping up in terms of temperature anomalies.


Global warming is felt most strongly in the Arctic as warming continues, as illustrated by above image and by the image on the right.

Warming in the Arctic is accelerating due to feedbacks. One of these feedbacks is the way the jet streams are changing. Changes in the jet streams are becoming more prominent as the Arctic is warming up more rapidly than the rest of the world.

jet streams
As the difference in temperature between the Arctic and the equator becomes smaller, the speed at which the jet stream circumnavigates the globe is decreasing and jet streams become more wavy.

Meanwhile, most of the extra heat caused by global warming goes into the oceans, and the Atlantic Ocean is warming up fast. At the same time, meltwater is accumulating at the surface of the North Atlantic, lowering sea surface temperatures there. With such large differences between high temperatures over North America and lower temperatures over the North Atlantic, the speed of the jet stream between those places can increase dramatically.

The result is that huge amounts of warm air are being pushed high into the Arctic. The image on the right shows the jet streams on December 27, 2015, when speeds as high as 263 mph or 424 km/h were reached at the location marked by the green circle. Also note the jet streams crossing the Arctic at the top of the image, while crossing the equator at the bottom of the image.

The image below shows sea surface temperature anomalies on the Northern Hemisphere in November.


For over a month now, storms over the North Atlantic have been pushing hot air high up into the Arctic. The video below uses surface wind content by Climate Reanalyzer (selected daily averages and sequences of forecasts) to cover the period from December 5, 2015, to January 8, 2016.



Best wishes for 2016
Above video stops at January 8, 2016, when two cyclones are visible, one in the North Atlantic and another one over the North Pacific, prompting me to create the image on the right.

What causes these storms to grow this strong? Waters keeps warming up dramatically off the east coast of North America. Emissions from North America tend to extend over these waters, due to the Coriolis effect, and this contributes to their extreme warming.

The image below shows carbon dioxide levels as high as 511 ppm over New York on November 5, 2015, and as high as 500 ppm over the water off the coast of coast of New Jersey on November 2, 2015. 


Emissions contribute to warmer waters - click to enlarge
The top panel of the image on the right shows that on December 11, 2015, carbon dioxide levels were as high as 474 ppm (parts per million, surface concentration) at the location marked by the green circle in New York.

The bottom panel of the image on the right shows that the water off the coast was warmer by as much as 10.3°C or 18.5°F at the location marked by the green circle on December 11, 2015.

The NASA video below shows carbon dioxide emissions over the year 2006.


It's not just CO2 off the North American coast that contributes to further warming of the Gulf Stream, many other emissions do so, including methane, CO, etc. Carbon monoxide (CO) is not a greenhouse gas, but it depletes hydroxyl, thus preventing oxidation of methane, a very potent greenhouse gas. The animation below shows a carbon monoxide level at green circle of 528 ppb on December 28, 2015, 0900z, while the sea surface temperature anomaly there was 15.8°F or 8.8°C on that day. 


Carbon monoxide reached much higher levels recently over land, as illustrated by the image below that shows a CO level of 2077 ppb in New York on January 6, 2016. 


These emissions heat up the Gulf Stream and make that ever warmer water is carried underneath the sea surface all the way into the Arctic Ocean, while little heat transfer occurs from ocean to atmosphere, due to the cold freshwater lid on the North Atlantic.

feedback #28 at the feedback page

The image on the right shows that it was warmer by as much as 9.6°C or 17.2°F near Svalbard on December 25, 2015, at the location marked by the green circle. The same anomalies were recorded on December 26, 2015, when the temperature of the water there was 11°C or 51.9 °F.

This gives an indication of how warm the water is that is being pushed underneath the sea surface into the Arctic Ocean.

Strong winds and high waves can cause more sea ice to be pushed along the edges of Greenland out of the Arctic Ocean, into the Atlantic ocean, expanding the cold freshwater lid on the North Atlantic, in a self-reinforcing feedback loop.

The image below shows the impact of these storms on sea ice speed and drift on December 31, 2015 (left) and a forecast for January 8, 2016 (right).


The danger is that, as warmer water reaches the seafloor of the Arctic Ocean, it will increasingly destabilize sediments that can contain huge amounts of methane in the form of free gas and hydrates.


Methane levels over the Arctic Ocean are already very high. Above image shows methane levels as high as 2745 ppb over the Arctic Ocean on January 2, 2016. High releases from the Arctic Ocean seafloor are pushing up methane levels higher in the atmosphere, as discussed in earlier posts such as this one.

So, while the extreme weather events that have occurred in the year 2015 are frightening, even more terrifying is the way the water of the Arctic Ocean is warming up. Sadly, this is rarely even discussed in the media. So, let's once more add the image below that should have been given more media attention.


The situation is dire and calls for comprehensive and effective action as described at the Climate Plan.



The year 2015 is shaping up to be the warmest year on record. In the media, a lot of attention has been given to the...
Posted by Sam Carana on Monday, December 28, 2015

Saturday 22 November 2014

How melting Arctic ice is driving harsh winters

by Nick Breeze

The very least 'global warming' could do for us is to give us warmer winters, right? Wrong, writes Nick Breeze, who met climate scientist and meteorologist Jennifer Francis in his attempt to understand the complex interactions of jet stream, polar vortex, the melting Arctic, and the extreme snowfall that's hitting the northeast US right now.

"Historic" snowfalls have the US northeast this week, with Buffalo, New York under an astonishing 2.4m (8ft) of snow - enough to cause some roofs to cave in under the pressure.

It's just the latest chapter in 2014 unprecedented range of weather extremes - from persistent storms that battered, and flooded much of the UK at the beginning of the year, before going on to record the hottest October since records began.

And in the US, extremes have ranged from California's record drought, to the early snows now under way in the northeast - and let's not forget the 'polar vortex' that hit much of the US in January, bringing Arctic conditions as far south as Texas and Florida, causing flights to be cancelled in Chicago as aviation fuel froze in the -38.3C (-37F) temperatures.



Scientists now have evidence that these persistent extreme weather patterns are increasing in their frequency, due to the rapid heating up of the Arctic that is changing the behaviour of the jet stream, and in turn, the polar vortex.

And Jennifer Francis of Rutgers University, one of the leading US scientists studying the relationship between Arctic warming and changes in the jet stream, believes that it's thanks to 'global warming' that northern hemisphere weather is becoming more extreme - and it's not about to get any better.

Screenshot from Youtube video further below

The 'vast river of wind' that makes our weather

"The Arctic is generally very cold", she told me, "and the areas farther south are warm, and that difference in temperature between those two areas is really what fuels that vast river of wind moving high over our head that we call the jet stream."

"The jet stream in turn creates most of the weather that we feel all around the northern hemisphere and the middle latitudes, so anything that affects this jet stream is going to affect weather patterns. So as the Arctic warms up much faster than the areas farther south, we're seeing this temperature difference between these two regions get smaller."

The result of that, she explains, is that the atmospheric forces driving the jet stream's circular motion are getting smaller - and that means the winds themselves in the jet stream are getting weaker, and moving more slowly.

"When that happens, the jet stream tends to take a wavier path as it travels around the northern hemisphere and those waves are actually what create the stormy patterns and the nice weather patterns. As those waves get larger because of this weakening of those winds of the jet stream, they tend to move more slowly from west to east."

"That means it feels like the weather patterns are sticking around longer, because those patterns are moving much more slowly and this then makes it more likely to have the kind of extreme events that are related to persistent weather patterns."



Are critical findings influencing policy?

These changes in climate have huge implications. As Dr Francis points out, there are "people who worry about whether there is enough fresh water to supply cities, whether there is enough snowpack on mountains to supply reservoirs, and for agriculture ..."

"Drought and agriculture is a big problem. Storminess in certain areas is another big problem. Yes, it has a huge impact for a whole range of issues that affect the way we live."

It's no wonder then that Dr Francis and her colleagues have attracted the attention of President Obama's chief science advisor, Dr John Holdren.

Dr Holdren has been reporting directly to the President on the real time effects of climate change and is keen to understand what this new research tells us about the future impact of changes to the jet stream.

Asked about this sudden interest in her work from the US Presidency, Francis muses thoughtfully. "Yes, we've had a lot of interest from policy makers", she acknowledges.

"I think we're starting to make a lot of progress now in getting policymakers to understand that this is a big problem they have to face ... I think decision makers and the policymakers at the local level get it much better because they're already seeing effects on their local areas.

"Sea level rise is an obvious one. They're already seeing changes in drought and agricultural problems and dealing with fresh water issues. It is really at the local level that we're having more success."

New research supports the case that Arctic sea ice loss is driving climate changes

So to understand the changes in the jet stream it's important to research how the vast atmospheric river of weather above our heads is connected to other climate mechanisms.

"It appears that over the north Atlantic, and towards Asia, there's a mechanism that appears to be quite robust, and several groups have found this mechanism using completely different analysis techniques", says Francis referring to new research by colleagues at the University of Alaska that has emerged in the last couple of months.

"So what we're finding is that there's an area, north of Scandinavia in the Arctic, where the ice has been disappearing particularly rapidly. When that ice disappears ... there is unfrozen ocean underneath, and that ocean absorbs a lot more energy from the sun through the summertime. So it becomes very warm there."

"Then as the fall comes around, all that heat that's been absorbed all summer long, where the ice has retreated, is put back in the atmosphere and that creates a big bubble of hot air ... over that region where the ice was lost."

And in turn, that goes on to disrupt the circumpolar winds whose behaviour determines much the weather across the northern hemisphere.

The gigantic bubble of warm air "tends to create a northward bulge in the jet stream", and in turn, "that creates a surface high pressure area that circulates in the clockwise direction. That sucks cold air down from the Arctic over northern Eurasia, and that creates a southward dip in the jet stream."



The bulging jet stream disrupts the polar vortex

"So what we're getting is this big northward bulge up over Scandinavia and a southward dip over Asia ... creating, first the tendency for a larger wave in the jet stream, which tends to move more slowly, but also we're seeing this mechanism that creates these colder winters that have been observed over Central Asia."

"Once the jet stream gets into this wavier pattern, it sends wave energy up into the highest levels of the atmosphere, which is called the stratosphere, where we have the polar vortex, which is kind of similar to the jet stream but it's much higher up in the atmosphere and it travels much faster."

"So as that wave energy gets sent up from this larger wave below, up into the stratosphere, it breaks down that polar vortex so that it becomes wavier as well. That wavier polar vortex sends energy back down to the lower atmosphere and it creates an even wavier jet stream in February."

"So we're seeing this connection of mechanisms that starts with Arctic sea ice loss and it makes a wavier jet stream for different reasons all the way through winter."

Will the jet stream continue to cause changes in climate?

By identifying these mechanisms and linking them back directly to loss of the Arctic sea ice, Dr Francis and her colleagues are demonstrating how man-made global warming is creating feedbacks that are changing the climate conditions in the northern hemisphere - and not for the better.

It may be counterintuitive, and it when it first happened it took scientists by surprise - but now it looks like this is one of the most important ways in which 'global warming' is hitting North America. Melting ice in the Arctic Ocean is indirectly pushing frigid Arctic air south across the continent, creating the perfect conditions for massive snowfall.

Which is all very well ... but what's coming next? "We are using these climate models, or computer simulations ... to try and project what we're expecting to see happen in the future, as greenhouse gases continue to increase.

"The early indications are that these large wavy patterns in the jet stream are going to become more frequent in the future, as far as we can tell. It is preliminary research that I haven't published yet but it does look as if they are going to increase."



Nick Breeze is a film maker and writer on climate change and other environmental topics. He has been interviewing a range of experts relating to the field of climate change and science for over four years. These include interviews with Dr James Hansen, Professor Martin Rees, Professor James Lovelock, Dr Rowan Williams, Dr Natalia Shakhova, Dr Michael Mann, Dr Hugh Hunt, among others.

Additional articles can also be read on his blog Envisionation.

Jennifer Francis is a research professor at the Institute of Marine and Coastal Sciences at Rutgers University, where she studies Arctic climate change and the link between Arctic and global climates. She has authored more than 40 peer-reviewed publications on these topics. She was also the co-founder of the Rutgers Climate and Environmental Change Initiative.

Article earlier posted at TheEcologist.org




Related





Wednesday 2 July 2014

What's wrong with the weather?


Above map shows temperatures in NewFoundland and Labrador close to 30°C (86°F), compared to temperatures in Albuquerque, New Mexico of only 20°C (68°F), while temperatures seem to be even lower in Mexico City. What's happening with the weather?

Jet Streams are changing


World climate zones used to be kept well apart by jet streams. On the northern hemisphere, the polar jet stream was working hard to separate the Tundra and Boreal climate zones' colder air in the north from the Temperate climate and the Subtropical climate zones' warmer air in the south.

As the Arctic is warming even faster than the Equator, the falling temperature difference between the two reduces the speed at which warm air is moving from the Equator to the North Pole. This in turn slows the speed at which the jet streams are circumnavigating the globe on the Northern hemisphere and it is deforming the jet streams in other ways as well.

NOAA image ]
As above image shows, the polar jet stream is typically located at about 60°N and the subtropical jet stream at about 30°N. The polar jet stream's altitude typically is near the 250 hPa pressure level, or 7 to 12 kilometres (4.3 to 7.5 mi) above sea level, while the weaker subtropical jet stream's altitude is higher, between 10 and 16 kilometres (6.2 and 9.9 mi) above sea level.

NOAA image
The polar jet stream used to travel at speeds of up to 140 miles per hour, while following a relatively straight track that was meandering only slightly, i.e. with waves that go up and down only a little bit. This fast and relatively straight jet stream kept climate zones well apart. Accordingly, the Northern Temperate Zone used to experience only mild differences between summer and winter weather, rather than the extremely hot or cold temperatures that we're increasingly experiencing now.

Polar jet stream (blue) & subtropical
jet stream (red) - NOAA image
Loss of snow and ice cover in the north is accelerating warming in the Arctic. This is decreasing the difference in temperature between the Arctic and the Northern Temperate Zone, in turn causing the polar jet to slow down and become more wavy, i.e. with larger loops, as illustrated by the animation below.

Imagine a river that at first rapidly runs down a narrow and straight path when its waters fall down from the top of a high mountain. Once that river flows through flat land, though, it becomes slow and curvy.

Similarly, the polar jet stream is now circumnavigating the globe at slower speed and along a wavier tracks. Its waves are now more elongated, more stretched out vertically, making that cold air can move more easily down from the Arctic, e.g. through the middle of North America, as illustrated by the animation below.

At the same time, warm air can move up more easily from the South into the Arctic. This is creating huge temperature anomalies in many places, as also illustrated by the animation below.


[ This animation is a 1.4MB file that may take some time to fully load ]
                Diagram of Doom, Sam Carana
These changes to polar jet stream constitute a self-reinforcing feedback that is further accelerating warming in the Arctic. As the jet stream slows down and its waves become more elongated, cold air can leave the Arctic more easily and descend deep into the Northern Temperate Zone. Conversily, more warm air can at the same time move north into the Arctic. The result is a warmer Arctic.

This 'open doors' feedback further decreases the difference in temperature between the Arctic and the Northern Temperate Zone, in turn further slowing down the jet stream and making it more wavy, and thus further accelerating warming in the Arctic.

This feedback is pictured in the image below as feedback #10.


Diagram of Doom - see Feedbacks in the Arctic for links


Arctic sea ice in steep descent

Global warming and the numerous feedbacks have a devastating impact on the sea ice, which is currently showing an almost vertical fall in extent, as illustrated by the image below.



Oceans are turning red

Arctic sea ice is also under threat from very warm waters. As the image below illustrates, oceans are turning red around the globe.



The image below shows that where the sea ice disappears, sea surface temperature anomalies as high as 8°C and higher show up.


Comprehensive and Effective Climate Action

The situation is dire, as huge amounts of methane are contained in sediments underneath the seafloor of the Arctic Ocean. Loss of sea ice means that huge amounts of heat that was previously reflected back into space will be absorbed by the Arctic Ocean. Furthermore, heat that previously went into melting the ice will also be absorbed by the water. Comprehensive and effective action is needed, as discussed at the Climate Plan blog.




Friday 16 May 2014

More extreme weather can be expected



The heaviest rains and floods in 120 years have hit Serbia and Bosnia this week, Reuters and Deutsche Welle report.

The animation below shows the Jet Stream's impact on the weather. Cold temperatures have descended from the Arctic to Serbia and Bosnia in Europe and all the way down to the Gulf of Mexico in North America, while Alaska, California, and America's East Coast are hit by warm temperatures. In California, 'unprecedented' wildfires and fierce winds lead to 'firenadoes', reports CNN.



The image below shows that on May 15, 2014, the wind approaching Serbia and Bosnia at 700 hPa reached speeds of up to 120 km per hour (75 mph), as indicated by the green circle on the main image and inset.


The image below, from skeptical science, shows the cyclonic spin that can be expected in a through such as the one that hit Serbia and Bosnia recently.


As the Jet Stream changes, more extreme weather events can be expected. What makes the Jet Stream change? As the Arctic is warming up faster than the rest of the world, the temperature difference between the Arctic and the equator decreases, in turn decreasing the speed at which the Jet Stream circumnavigates the globe. This can cause 'blocking patterns', with extreme weather events hitting an area longer than before.

As the jet stream becomes wavier, cold air can more easily descend from the Arctic down to lower latitudes in a downward through of the Jet Stream, while warm air can more easily reach higher latitudes in an upward ridge of the Jet Stream.

This spells bad news for many areas across the world that can be expected to be hit by more extreme weather events such as heatwaves, wildfires fuelled by stronger winds and more intense drought, storms and floods.

Heatwaves are a huge threat in the Arctic, especially when followed by storms that can cause warm surface water to mix down to the bottom of the sea and warm up sediments under the seafloor that can contain huge amounts of methane in the form of hydrates and free gas. The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan blog.


Related

- Extreme weather strikes around the globe - update
http://arctic-news.blogspot.com/2014/02/extreme-weather-strikes-around-the-globe-update.html

- Escalating extreme weather events to hammer humanity (by Paul Beckwith)
http://arctic-news.blogspot.com/2014/04/escalating-extreme-weather-events-to-hammer-humanity.html

- Our New Climate and Weather (by Paul Beckwith)
http://arctic-news.blogspot.com/2014/01/our-new-climate-and-weather.html

- Our New Climate and Weather - part 2 (by Paul Beckwith)
http://arctic-news.blogspot.com/2014/01/our-new-climate-and-weather-part-2.html

- Changes to Polar Vortex affect mile-deep ocean circulation patterns
http://arctic-news.blogspot.com/2012/09/changes-to-polar-vortex-affect-mile-deep-ocean-circulation-patterns.html

- Polar jet stream appears hugely deformed
http://arctic-news.blogspot.com/2012/12/polar-jet-stream-appears-hugely-deformed.html