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Tampilkan postingan dengan label wind. Tampilkan semua postingan
Tampilkan postingan dengan label wind. Tampilkan semua postingan

Kamis, 01 Oktober 2015

Cyclones continue to hit Northern Hemisphere

As the 2015 El Niño gets stronger, the Northern Hemisphere continues to get hit by strong winds and cyclones. The image below shows strong winds over the Arctic Ocean, as hurricane Joaquin approaches the coast of North America.



On above image, hurricane Joaquin is clocked at a speed of 79 mph (127 km/h) on October 1, 2015. NOAA warned that on that day the maximum sustained wind speed had increased to near 120 mph (195 km/h) with higher gusts.

For reference, NOAA uses four categories:
D: Tropical Depression – wind speed less than 39 mph (63 km/h)
S: Tropical Storm – wind speed between 39 mph and 73 mph (63 km/h - 118 km/h)
H: Hurricane – wind speed between 74 mph and 110 mph (118 km/h - 177 km/h)
M: Major Hurricane – wind speed greater than 110 mph (over 177 km/h)

NOAA issued the image below on September 30, 2015, warning that Hurricane Joaquin is likely to cause wind damage across a large part of the eastern coast of North America.


The NOAA animation below gives an idea of the strength of hurricane Joaquin.

[ click on image to enlarge, note that this is a 1.4 MB file that may take some time to fully load ]

Meanwhile, sea surface temperatures off the North American coast, as well as in the Arctic Ocean, are very high, as illustrated with the image on the right.

In the Arctic Ocean, the sea ice in many places is now less thick than it was in 2012, as illustrated by the image further below, showing sea ice thickness on October 7, 2012 (panel left) and a forecast for October 7, 2015 (panel right).

The water in the Arctic Ocean was already very warm this year. The main factor causing both these strong winds and the dramatic decrease in thickness of the multi-year sea ice is ocean heat, as also illustrated by the image below, showing high sea surface temperature anomalies in the Arctic as at September 30, 2015.


As the image below shows, nearly all the thick (over 3 m) multi-year sea ice has now disappeared, setting up a dangerous situation for the future that is much more dangerous than the situation was back in 2012. The thicker sea ice used to act as a buffer, consuming ocean heat in the melting process. Without thicker sea ice, ocean heat threatens to melt the sea ice from below right up to the surface, causing the entire sea ice to collapse as more open water will go hand in hand with stronger winds and waves. In case of such a collapse, sunlight that was previously reflected back into space will instead be absorbed by the water, causing rapid rise of the temperature of the water. In places such as the East Siberian Arctic Shelf, the water is on a average only 50 m deep, so warmer water is able to reach the seafloor more easily there.


The water of the Arctic Ocean is very warm, not only at the surface, but even more so underneath the surface. The danger is that strong winds will mix warm water all the way down to the seafloor, where it could destabilize sediments that can contain huge amounts of methane in the form of hydrates and free gas.

[ click on image to enlarge ]
The image on the right illustrates the impact of winds over the East Siberian Arctic Shelf on September 26, 2015.

NSIDC specialist Julienne Stroeve recently warned: "In 2007 more than 3m of bottom melt was recorded by [an] ice mass balance buoy in the region, which was primarily attributed to earlier development of open water that allowed for warming of the ocean mixed layer. But perhaps some of this is also a result of ocean mixing."

As discussed in an earlier post, sea surface anomalies of over 5°C were recorded in August 2007 in the Arctic Ocean. Strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007 and bottom water temperatures on the mid-shelf increased by more than 3 degrees Celsius compared to the long-term mean.

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



As the 2015 El Niño gets stronger, the Northern Hemisphere continues to get hit by strong winds and cyclones. The image...
Posted by Sam Carana on Thursday, October 1, 2015

Jumat, 24 Juli 2015

Thick Sea Ice Dislodged

As the comparison image below shows, the last bit of thick sea ice has become dislodged from its location in the Canadian Archipelago and is forecast to be floating along with the sea ice in the Arctic Ocean. The left panel shows the situation on July 19, 2015, while the right panel shows a forecast for July 31, 2015, run on July 23, 2015.


One reason for this development is of course the heavy melting that has taken place in this area. But what has made this thick sea ice move so strongly? The reason for this is a combination of wind, sea currents and meltwater running off the coasts of North America and Greenland. This has been persistently pushing this thick ice in this direction, as illustrated by the Naval Research Laboratory animation below.


The Naval Research Laboratory animation below shows sea ice thickness over a 30-day timespan, including a forecast up to 31 July, 2015, run July 23, 2015.


The screenshot below from arctic-io shows the sea ice on July 23, 2015, with an inset showing a rotated outcut from a Naval Research Laboratory ice thickness map for that date.
[ click on image to enlarge ]
The animation below shows a 5-day forecast of ice speed and drift up to July 27, 2015, starting from and run on July 23, 2015.


Furthermore, there has been a lot of smoke from wildfires in North America for some time. The image below shows smoke reaching far into the Beaufort Sea on July 22, 2015.



When smoke settles on snow and ice, it decreases albedo and makes it more prone to melting.

Seismic activity could also have contributed to this development. As the snow and ice cover on land disappears, isostatic rebound occurs, i.e. the land moves upward. Furthermore, an earthquake with a magnitude of 3.6 on the Richter scale was registered in Baffin Bay on July 22, 2015.


Above animation shows the last bit of thick sea ice becoming dislodged from its location in the Canadian Archipelago, from July 21, 2015, through to July 24, 2015.


Albert Kallio comments: "The more ice moves, the more heat it can pick up from the ocean - and melt. Also, the overturning of sea water in the ocean increases in the increasingly open sea areas - bringing heat up to the surface - and into contact with ice that then melts faster."

[ hat tip to Patrick McNulty for contributions to this post ] 



The last bit of thick sea ice has become dislodged from its location in the Canadian Archipelago and is forecast to be...
Posted by Sam Carana on Friday, July 24, 2015

Jumat, 06 Maret 2015

March 4, 2015 - Arctic Sea Ice Extent Hits Record Low

Sea surface temperature anomalies as high as 12°C (21.6°F) recorded off the east coast of North America have been described earlier, in he post 'Watch where the wind blows'. The Jet Stream reaching high speeds has also been described earlier, in the post 'Climate Changed'.


As feared, this is pushing warm water, water vapor and air from the North Atlantic into the Arctic Ocean. The three images below show forecasts for March 8, 2015, of - from top to bottom - the jet stream, surface winds and temperature anomalies.





Above image shows that the Arctic is forecast to reach a temperature anomaly of more than +4 degrees Celsius (more than +7 degrees Fahrenheit) on March 8, 2015, with temperature anomalies at the top end of the scale forecast for most of the Arctic Ocean.

On March 4, 2015, Arctic sea ice extent hit a record low for the time of the year, as illustrated by the image below.


As the March 5, 2015, Naval Research Laboratory image on the right illustrates, there is little scope for Arctic sea ice extent to grow over the next few weeks, since the only areas where it could possibly expand would be the Pacific and the North Atlantic, the very areas that are under pressure from ocean heat and high surface temperatures.

In other words, the situation looks set to deteriorate further.

Huge amounts of heat are still going into melting the sea ice. Furthermore, the sea ice is still able to reflect a lot of sunlight back into space. With continued demise of the snow and ice cover, more and more heat will be absorbed in the Arctic.

The big danger is that warm water will trigger further releases of methane from the seafloor of the Arctic Ocean. Peak daily methane levels recorded in early 2015 averaged a very high 2372 parts per billion, as illustrated by the image below.


Methane extent has been especially high over the Arctic Ocean. The images below are from the earlier post 'Temperature Rise'. The post added that, as the Gulf Stream keeps carrying ever warmer water into the Arctic Ocean, methane gets released in large quantities, as illustrated by the images below showing high methane levels over the East Siberian Arctic Shelf (red oval left) and over Baffin Bay (red oval right) with concentrations as high as 2619 ppb.

click on image to enlarge
The images below show methane levels on Jan 25 (top), and Jan 26, 2015 (bottom).


Update:
Meanwhile, Arctic sea ice extent as reported by NSIDC.org reached a new record low for the time of the year with 14.358 million square km on March 4, 2015, and another record low with 14.308 million square km on March 7, 2015.

Temperature anomaly for the Arctic on March 8, 2015 (daily average) was even higher tha forecast, at +4.26 degrees Celsius, with peaks at +4.37 degrees Celsius.



High waves were registered in the North Atlantic on March 7, 2015, moving into the Arctic Ocean and causing waves more than 4 m high close to the edge of the sea ice on March 8, 2015.



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


Selasa, 03 Februari 2015

Watch where the wind blows

The Arctic looks set to be pummeled by strong winds on February 5, 2015, as shown by the Climate Reanalyzer forecast below.


The video below, based on Climate Reanalyzer images, watch the situation unfold over a period of 9 days



Strong winds can increase the transport of warm water into the Arctic Ocean by the Gulf Stream. The video shows strong winds repeatedly developing off the North American east coast and moving along the path of the Gulf Stream, all the way into the Arctic Ocean, all in a matter of days.

Emissions are causing greater warming of the Gulf Stream and the Arctic. As a result, there is less temperature difference between the equator and the Arctic, slowing down the speed at which the jet streams circumnavigate the globe, while the jets can also become wavier, which in turn can cause extreme weather events.

In this case, what fuels these winds is the temperature difference between an area off the east coast of North America where temperatures are much higher than they used to be on the one hand, and an area in Siberia where temperatures are extremely low on the other hand. Wind flows from a warm area to a cold area, and the greater the temperature difference, the stronger the wind will blow.

The image below shows that, on February 3rd, 2015, a sea surface temperature of 21°C (69.8°F) was recorded off the east coast of North America (green circle), which constitutes a 12°C (21.6°F) anomaly. Anomalies as high as 12°C were also recorded on February 4, 2015.

click on image to enlarge
Changes to the jet streams can thus fuel strong winds, and such winds can bring warmer air into the atmosphere over the Arctic Ocean. On February 5, 2015, surface temperatures over a large part of the Arctic Ocean were more than 20°C (36°F) warmer compared to what they were from 1985 to 1996.


Extreme weather events, as a result of changes to the jet streams and polar vortex, are depicted as feedback #19 in the diagram below, while storms that bring warmer air into the atmosphere over the Arctic Ocean are depicted as feedback #5,

Besides increasing the transport of warm water into the Arctic Ocean and bringing warmer air into the atmosphere over the Arctic Ocean, strong winds can also break up the sea ice by sheer brute force of the waves caused by the wind.

Waves as high as 10.61 m (34.81 ft) were recorded south of Greenland on February 4, 2015, while waves as high as 7.05 m (23.13 ft) were recorded on the edge of the Arctic sea ice (east of Svalbard) on February 5, 2015, as shown on the combination image below.



Waves that break up the sea ice into smaller pieces can speed up melting, especially in summer. More wind also means more water evaporation, and warmer air holds more water vapor, so this can result in huge rainstorms that can rapidly devastate the integrity of the ice. Strong winds thus constitute a feedback that can result in more open waters in the Arctic Ocean (feedback #6 on the diagram below).

Furthermore, strong winds can speed up the currents that will eventually move sea ice out of the Arctic Ocean into the Atlantic Ocean (feedback #7). Wavy waters catch more sunlight than still water (feedback #8). Decline of the Arctic snow and ice cover results in more sunlight being absorbed by the Arctic, thus further heating up the water of the Arctic ocean (feedback #1).

The dual image below, with images from Climate Reanalyzer, shows high sea surface temperatures around North America and at the edges of the Arctic sea ice. This contributes to surface temperatures that are 20°C (36 °F) higher than what they used to be in Eastern Siberia. At the same time, temperatures on land elsewhere in Siberia, on the North Pole and in parts of Canada and Greenland can go down to 40 degrees below zero.



Accelerated warming of the Arctic is changing the jet streams, in turn contributing to the likelyhood that such strong winds will hit the Arctic. The high temperature difference between the hot spot off the North American east coast and the cold spot over Siberia fuels such strong winds. The dual images below show the jet stream's elongated path over Greenland. Accordingly, temperature anomalies in Greenland are reaching the top end of the scale.



The big danger is that such strong winds will warm up the Arctic Ocean and cause huge amounts of methane to erupt from its seafloor.

The image below shows that methane levels as high as 2503 ppb were recorded on January 31, 2015.



Such methane eruptions constitute yet another feedback that further contributes to warming in the Arctic. For more feedbacks, see the image below.

from:  climateplan.blogspot.com/p/feedbacks.html

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





Selasa, 22 April 2014

Arctic Sea Ice in Steep Descent

Arctic sea ice area is in steep descent, as illustrated by the image below. Sea ice area was only smaller at this time of the year in 2007, for all years for which satellite data are available.

[ click on image to enlarge ]
Earlier this year, on March 9, 2014, Arctic sea ice area was at a record low for the time of the year. Since then, area did show some growth for a while, to the north of Scandinavia. This growth could be attributed largely to strong winds that made the sea ice spread with little or no growth in volume. The 30-day Naval Research Laboratory animation below shows recent sea ice speed and drift.


Indeed, sea ice volume in March 2014 was the 2nd lowest on record. Only March 2011 had a lower volume as discussed in a recent post. The 30-day Naval Research Laboratory animation below shows recent sea ice thickness. 



Low sea ice volume and area jointly suggest there could be a total collapse of the sea ice later this year, in line with observation-based non-linear trends. For years, this blog has warned that observation-based projections point at Arctic sea ice disappearance within years, with dire consequences for the Arctic and for the world at large.

As said, winds are responsible for much of sea ice variability, and winds could either slow down or speed up such a collapse. On this point, it's good to remember what Prof. Peter Wadhams said in 2012:
". . apart from melting, strong winds can also influence sea ice extent, as happened in 2007 when much ice was driven across the Arctic Ocean by southerly winds. The fact that this occurred can only lead us to conclude that this could happen again. Natural variability offers no reason to rule out such a collapse, since natural variability works both ways, it could bring about such a collapse either earlier or later than models indicate.

In fact, the thinner the sea ice gets, the more likely an early collapse is to occur. It is accepted science that global warming will increase the intensity of extreme weather events, so more heavy winds and more intense storms can be expected to increasingly break up the remaining ice, both mechanically and by enhancing ocean heat transfer to the under-ice surface."
The image on the right, produced with NOAA data, shows mean coastal sea surface temperatures of over 10°C (50°F) in some areas in the Arctic on August 22, 2007.

In shallow waters, heat can more easily reach the bottom of the sea. In 2007, strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007, found a 2011 study, and bottom water temperatures on the mid-shelf increased by more than 3°C (5.4°F) compared to the long-term mean.

Another study found that drastic sea ice shrinkage causes increase in storm activities and deepening of the wind-wave-mixing layer down to depth ~50 m (164 ft) that enhance methane release from the water column to the atmosphere. Indeed, the danger is that heat will warm up sediments under the sea, containing methane in hydrates and as free gas, causing large amounts of this methane to escape rather abruptly into the atmosphere.

Such warming would come on top of ever-warmer water that is carried by the Gulf Stream into the Arctic Ocean and that has already been blamed for large methane releases from the seafloor of the Arctic Ocean last year.

The prospect of an El Niño event, as discussed in an earlier post, makes the situation even more dire.

The consequences of sea ice collapse will be devastating, as all the heat that previously went into transforming ice into water will be asbsorbed by even darker water, from where less sunlight will be reflected back into space. The danger is that further warming of the Arctic Ocean will trigger massive methane releases that could lead to extinction at massive sclae, including extinction of humans.

Hopefully, more people will realize the urgency of the situation and support calls for comprehensive and effective action as discussed at the Climate Plan blog.



Links

- March 2014 Arctic Sea Ice Volume 2nd Lowest On Record
http://arctic-news.blogspot.com/2014/04/march-2014-arctic-sea-ice-volume-2nd-lowest-on-record.html

- Supplementary Evidence by Professor Peter Wadhams
http://arctic-news.blogspot.com/2012/04/supplementary-evidence-by-prof-peter.html

- Has the Descent begun?
http://arctic-news.blogspot.com/2014/03/has-the-descent-begun.html

- Nea-term Human Extinction
http://arctic-news.blogspot.com/2014/04/near-term-human-extinction.html

- Climate Plan blog
http://climateplan.blogspot.com