Showing posts with label winds. Show all posts
Showing posts with label winds. Show all posts

Tuesday 8 December 2015

Strong winds and High Waves hit Arctic Ocean


Strong winds and high waves are hitting the Arctic Ocean from both the Atlantic Ocean and the Pacific Ocean.

Above image shows waves as high as 12.36 m or 40.5 ft near Greenland on December 8, 2015.

The image on the right shows cyclonic winds with speeds as high as 142 km/h or 88 mph near Greenland on December 8, 2015.

The image further down on the right shows that waves as high as 14.04 m or 46.1 ft are forecast to hit the Aleutian Islands on December 13, 2015. Strong winds and high waves are forecast to subsequently keep moving in the direction of the Arctic Ocean.

The image below shows strong winds and high waves that are heading for Arctic Ocean, with waves as high as 17.18 m or 56.4 ft forecast to be moving toward the Arctic Ocean on December 13, 2015.

As warming continues, this situation can be expected to get worse, with extreme weather events hitting the Arctic Ocean with ever greater intensity.


The video below, created with Climate Reanalyzer images, shows strong winds over the period from December 5 to 15, 2015. The video illustrates how cyclonic winds are hitting the Arctic Ocean both from the Atlantic Ocean and the Pacific Ocean.


Such winds and waves can move a lot of warm water into the Arctic Ocean. There currently is only a very thin layer of sea ice present in the Bering Strait, which is prone to be broken up by strong waves. Moreover, warm water may move underneath the sea ice and cause warm water to mix down all the way to the seafloor, where it can destabilize sediments containing huge amounts of methane in the form of free gas and hydrates.

Furthermore, strong winds can dramatically speed up the currents that are moving sea ice out of the Arctic Ocean into the Atlantic Ocean. The Naval Research Laboratory animation below shows ice speed and drift, illustrating how strong winds are pushing huge amounts of sea ice out of the Arctic Ocean along the edge of Greenland into the Atlantic Ocean.


The Naval Research Laboratory animation below illustrates that the thicker sea ice has hardly grown recently, while large amounts of thick sea ice also get pushed out of the Arctic Ocean along the edge of Greenland into the Atlantic Ocean.


[ click on image to enlarge ]
The image on the right shows that, on December 11, 2015, sea surface temperature anomalies off the east coast of North America were as high as 18.1°F or 10.0°C compared to the daily average during years 1981-2011.

At the same time, the lid over the North Atlantic is expanding, due to heavy melting of glaciers and due to the large amounts of sea ice that are getting pushed out of the Arctic Ocean by strong winds. Expansion of the freshwater lid over the North Atlantic is cooling the sea surface of North Atlantic and is making the atmosphere over the North Atlantic cooler than it would be without this lid, as it makes that less heat gets transferred from ocean to atmosphere, as discussed in earlier posts such as this one.

The result is a widening difference in atmospheric temperature between the area off the east coast of North America and the North Atlantic. This widening difference causes stronger winds to flow to the North Atlantic, in turn causing more sea ice to be moved out the the Arctic Ocean and further speeding up this feedback (#28 at the feedbacks page).


The end result is that, due to this loss of sea ice occurring now, the sea ice will be in a very bad shape when the melting season starts again next year. Furthermore, this expanding lid on the North Atlantic will prevent heat transfer from ocean to atmosphere, resulting in warmer water arriving in the Arctic Ocean below the sea surface.

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



Waves as high as 12.36 m or 40.5 ft near Greenland on December 8, 2015. From the post 'Strong winds and High Waves hit...
Posted by Sam Carana on Tuesday, December 8, 2015

Sunday 15 March 2015

Strong Winds And Waves Batter Arctic Sea Ice

As Earth warms, the intensity of storms is rising across the globe. At least eight people died in Vanuatu, as it was hit by Cyclone Pam. "It hit Port Vila at an incredible 340 kilometres an hour", mentions a recent news report. The left part of the image below shows Cyclone Pam reaching speeds as high as 144 kilometers an hour (89.48 mph, green circle) on March 12, 2015, 1500Z, while three further cyclones feature on the Southern Hemisphere. 


At the same time, on the Northern Hemisphere, winds reached speeds as high as 101 km/h (62.76 mph, bottom green circle), 120 km/h (74.56 mph, middle green circle) and 112 km/h (69.59 mph, top green circle), as shown on the right part of above image.

The image on the right shows winds with speeds as high as 125 km/h (77.67 mph) batter the coast of Greenland on March 13, 2015 (green circle).

The image below shows strong winds moving from the North Atlantic into the Arctic Ocean on March 13, 2015. 


The video below, with cci-reanalyzer.org forecasts for March 13 - 20, 2015, shows strong winds battering the Arctic Ocean at both the Pacific and Atlantic ends.



The combination image below shows winds around Greenland (top) and winds penetrating the Arctic Ocean (bottom).


Waves as high as 41.5 ft (12.65 m) were recorded between Svalbard and Norway on March 13, 2015 (green circle on the left part of the image below), while waves as high as 23.13 ft (7.05 m) were recorded close to the edge of the sea ice on March 15, 2015 (green circle on the right part of the image below).


The updated image below shows waves higher than 10 m (33 ft) near Svalbard close to the edge of the sea ice on March 16, 2015 (green circle).


Meanwhile, it more and more looks like the 2015 sea ice extent maximum was reached on February 25, as illustrated by the image below.


The image below (added later, ed.) shows Arctic sea ice area up to March 18, 2015 (top), and Arctic sea ice extent up to March 20, 2015 (bottom). Briefly, the difference between area and extent could be compared to Swiss cheese. Area is the cheese without the holes, while extent measures the cheese in addition to the holes. For more on this, see this NSIDC FAQ.


Strong winds can cause high waves that can break up the sea ice. At the same time, strong winds can speed up currents that push sea ice out of the Arctic Ocean, while bringing warmer water into the Arctic Ocean, as illustrated by the image below.


The image below shows sea surface temperatures of 20.9°C (69.62°F, green circle left) recorded off the coast of North America on March 14, 2015, an anomaly of 12.3°C or 26.54°F.

[ click on image to enlarge ]
The image below shows sea surface temperature anomalies in the Arctic Ocean on March 15, 2015.



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 2370 parts per billion, as illustrated by the image below.


Natalia Shakhova et al. estimate the accumulated methane potential for the Eastern Siberian Arctic Shelf (ESAS, rectangle on image right) alone as follows:
- organic carbon in permafrost of about 500 Gt;
- about 1000 Gt in hydrate deposits; and
- about 700 Gt in free gas beneath the gas hydrate stability zone.

Hydrates can become destabilized by pressure changes that can be caused by earthquakes and resulting shockwaves and landslides, or that can be caused by wild temperature swings.

Hydrates can also become destabilized by a small temperature rise that can be caused by influx of warmer water from outside the Arctic Ocean or by warm surface water being mixed down by storms.

Waters in the ESAS are quite shallow, averaging less than 50 m depth over its 2x10ˆ6 km2 area, while methane hydrates in the ESAS can exist at depths as shallow as 20 m.

Where heat is able to penetrate the sediment along cracks, some hydrate destabilization can occur, which in turn can trigger larger destabilization, as methane escaping from a hydrate expands to 160 times its earlier volume; this explosive expansion can cause further destabilization of sediments containing 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.