Showing posts with label fall. Show all posts
Showing posts with label fall. Show all posts

Monday, January 16, 2017

Global sea ice extent falling off chart

Global sea ice extent is falling off the chart, as illustrated by the image below.

[ click on images to enlarge ]
The National Snow & Ice Data Center (NSIDC) is one of the world's best-know archives for satellite data on sea ice.

In its recent news release, NSIDC notes that the difference between the 1981-2010 average global sea ice extent and the 2016 extent was over 4 million km² in mid-November 2016 (image on the right).

The fall in sea ice extent constitutes a huge amount of energy that is no longer reflected back into space and is instead absorbed by the ocean, the atmosphere and by the process of melting itself.

In line with earlier calculations by Professor Peter Wadhams, a 4 million km² sea ice decrease could equate to a radiative forcing of as much as 1.3 W/m². All this extra energy does not directly translate into a rise in temperature of the atmosphere, since a lot of energy has over the past few decades been absorbed by the ocean and has also gone into the process of melting itself. However, it now looks like the temperature of the atmosphere is catching up fast, as illustrated by the image below.



[ click on images to enlarge ]
On the right is a forecast by the European Centre for Medium-Range Weather Forecasts (ECMWF).

It shows that we've barely been in a La Niña, which typically makes the atmosphere cooler than it would otherwise have been.

Already now, another El Niño is on the way that could soon make it up to 2.5°C warmer than it is was late last year.

Global sea ice volume is also at record low, as illustrated by the image below on the right.
Arctic sea ice thickness hit a record low in November 2016 when thickness fell below 0.7 m or 2.3 ft.

As the ice gets thinner, the risk of collapse grows, as increasingly stronger winds and storms and stronger wave action can more easily break up thin sea ice, making it more vulnerable to melting and to get carried out of the Arctic Ocean by stronger cyclonic winds and stronger exit currents.

Disappearance of Arctic sea ice increases the risk of huge methane releases from the seafloor of the Arctic Ocean. The outlook is terrifying. As I calculated last year, surface temperatures of the atmosphere could rise by some 10°C or 18°F within a decade, i.e. by 2026.

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


Links

• Climate Plan
http://arctic-news.blogspot.com/p/climateplan.html

• Extinction
http://arctic-news.blogspot.com/p/extinction.html

• How much warming have humans caused?
http://arctic-news.blogspot.com/2016/05/how-much-warming-have-humans-caused.html



Monday, May 16, 2016

Further Confirmation Of Arctic Sea Ice Dramatic Fall

Since early April, 2016, there have been problems with the sensor on the F-17 satellite that provided the data for many Arctic sea ice images. On April 12, NSIDC issued a notice that it had suspended the provision of sea ice updates. On May 6, NSIDC announced that it had completed the shift to another satellite. The red dotted line in the image below shows data from the F-18 satellite from April 1 to May 15, 2016.

The JAXA site also provides sea ice extent images, obtaining data from a Japanese satellite. They show that Arctic sea ice extent on May 15, 2016 was 11,262,361 square km, 1.11 million square km less than it was on May 15, 2012.


The Cryosphere Today is still using data from the F17 satellite, showing some weird spikes. Albert Kallio has taken a recent image and removed faulty spikes, resulting in the image below showing sea ice area up to May 3, 2016.

[ yellow line is 2016, red line is 2015 ]
Importantly, above image confirms that Arctic sea ice in 2016 has indeed been very low, if not at its lowest for the time of the year. Especially since April 2016, sea ice has fallen far below anything we've seen in earlier years. Below, Albert elaborates on comparing data.


by Albert Kallio

REPAIRED USA (F-17) SATELLITE DATA SHOWS RECORD SMALL SEA ICE AREA IN MAY 2016 AGREEING JAPANESE (JAXA) DATA

A corrected Special Sensor Microwave Imager and Sounder (SSMIS) data set on the Defense Meteorological Satellite Program (DMSP) F-17 satellite that provides passive microwave brightness temperatures (and derived Arctic and Antarctic sea ice products) has been corrected here for the system instrumentation error. This agrees with the Japanese JAXA curve, and has been accomplished by removal of the uncharacteristic upward 'ice growth' spikes by linear intrapolation of the corrupt data points. This reinforces the JAXA data that shows the Northern Hemisphere sea ice area is seasonally at new record low which has continued in May 2016.

Smoothened F-17 curve agrees with the Japanese JAXA satellite curve. The reconciliation of the two has been accomplished by removal of the uncharacteristic upward spikes by linear intrapolation of the corrupt days' data points which incorrectly showed immense sea ice area growth in the middle of spring melt season. This reinforces the JAXA data that shows the sea ice area is seasonally at record lows. Therefore, media who are citing recent F-17 satellite sea ice area figures are intentionally distorting the facts with their claims of the Northern Hemisphere having a record sea ice area for this time of season - whereas in reality - the exact opposite has been happening.

Arctic sea ice is in a bad shape and looks set to deteriorate even further, for a number of reasons.

The year 2016 is an El Niño year, as illustrated by the 51.1°C (124.1 °F) forecast for May 22, 2016, over the Indus Valley in Pakistan (see image right).

Insolation during the months June and July is higher in the Arctic than anywhere else on Earth. Greenhouse gases are at record high levels: CO2 was 408.2 ppm on May 12, 2016, and methane levels are high and rising, especially over the Arctic.

Ocean heat is also very high and rising. The image below shows that oceans on the Northern Hemisphere were 0.93°C (or 1.7°F) warmer in the most recent 12-months period (May 2015 through April 2016) than the 20th century average.


The situation is further illustrated by the image below, using the NOAA data with a trendline added that points at a rise of 3°C (5.4°F) before the year 2040.


Chances are that Arctic sea ice will be largely gone by September 2016. As the ice declines, ever more sunlight gets absorbed by the Arctic Ocean. This is one out of numerous feedbacks that are hitting the Arctic. The danger is that, as these feedbacks start to kick in more, heat will reach the seafloor of the Arctic Ocean and trigger methane to be released in huge quantities from the Arctic Ocean seabed.

Recently, an abrupt methane release from the Arctic Ocean seafloor did enter the atmosphere over the East Siberian Sea, showing up with levels as high as 2578 ppb (at 586 mb on May 15, 2016, pm, see image below). Such abrupt releases are indications that methane hydrates are destabilizing and are warnings that climate catastrophe is waiting to happen.


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


Monday, November 23, 2015

Arctic Ocean Shows New Record Low Sea Ice

by Albert Kallio


Both the sea ice thickness and sea ice area have fallen to new record lows for this time of the year (22.11.2015), even surpassing all of the worst previous years.

From Naval Research Laboratory image - view animation
Immense thrust of fast moving sea ice is pushing through at the full width of the Fram Strait between Norway and Greenland. This amounts to huge transport of latent coldness out of the Arctic Ocean to North Atlantic, while the constantly forming new sea ice (as temperatures are below 0°C) is generating heat to keep the surface air temperatures higher across the Arctic Ocean. Thus, heat is constantly being added to the Arctic Ocean while heat is taken away from the North Atlantic Ocean.


The normal sea ice area for this time of year is 9,625,000 km2, whereas the sea ice covers currently just 8,415,890 km2,, which makes that 1,209,120 km2 sea ice is missing from the normal (22.11) sea ice area.



The combination image below shows the jet stream (November 23, 2015, left panel) and surface wind (November 24, 2015, right panel).


Jet stream is wavy and strong, showing speeds as high as 219 mph or 352 km/h (at location marked by the green circle). Right panel shows cyclonic winds between Norway and Greenland speeding up movement of sea ice into the North Atlantic.

Forecasts indicate that conditions could continue. The 5-day forecast on the right shows strong winds in the North Atlantic. Note also the cyclonic winds outside the Bering Strait.

Temperatures over the Arctic are forecast to remain much higher than they used to be, with anomalies at the far end of the scale over a large part of the Arctic Ocean showing up on the 5-day temperature anomaly forecast below.




[ further updates will follow ]