Showing posts with label cyclone. Show all posts
Showing posts with label cyclone. Show all posts

Saturday, August 24, 2019

Cyclone over Arctic Ocean - August 24, 2019

As illustrated by above map, Arctic heating is accelerating, with temperatures showing up in the Arctic that are up to 4.41°C hotter than the average global temperature during 1880-1920.

The image below shows two plots. On the left-hand side is the temperature plot associated with above map, had a monthly mean been selected. To smooth the data, a 4-year running mean was chosen, and the plot on the right-hand side shows the associated global mean anomalies. Note that, due to this smoothing, only data from 1882 to August 2017 are displayed in the plot of the right-hand side.

It is appropriate to adjust the data by 0.5°C, as follows:
  1. An adjustment of 0.3°C to reflect a pre-industrial baseline (heating occurred due to people's emissions before 1880-1920);
  2. An adjustment of 0.1°C to reflect air temperatures over oceans (as opposed to sea surface temperatures);
  3. An adjustment of 0.1°C to better include polar temperatures (the top and bottom of the image at the top shows large polar areas that should not be excluded, the more so since the Arctic has the highest temperature anomalies).
The image below shows both adjusted and unadjusted data as dark blue lines, with a light-blue polynomial trend added over the adjusted data.

Such a trend can further smooth out seasonal differences and El Niño/La Niña variability.

Such a trend can also show the potential for further temperature rise in the near future, which can constitute an important warning.

This is particularly important as the trend shows that we could be crossing the 2°C guardrail this year, i.e. the threshold that was too dangerous to be crossed.

What is the danger? Arctic heating is accelerating, as the image at the top shows, and this could make global temperatures skyrocket in a matter of years. Where Arctic sea ice disappears, hot water emerges due to albedo changes and loss of the buffer that has until now been consuming heat as part of the melting process. This is illustrated by the image below showing the sea surface temperature difference from 1961-1990 in the Arctic at latitudes 60°N - 90°N on August 23, 2019.

Disappearance of Arctic sea ice comes with numerous feedbacks that further speed up the heating, as described in the recent post Arctic Sea Ice Gone By September 2019?. Heatwaves can strongly heat up the water that gets carried by rivers into the Arctic Ocean. As the image below shows, the water was as hot as 10.7°C or 51.3°F at green circle on August 20, 2019, i.e. 9.4°C or 16.9°F hotter than 1981-2011.

As the Arctic is heating up faster than the rest of the world, the Jet Stream gets more and more distorted. A cyclone is forecast over the Arctic Ocean for August 24, 2019, pulling hot air over the Arctic Ocean, resulting in temperatures at the green circle as high as 10.4°C or 50.6°F at 1000 hPa and 7.4°C or 45.2°F at surface level, as the image below shows.

The image below illustrates the distortion of the Jet Stream, moving over the Arctic Ocean on August 24, 2019.

Such a cyclone can pull huge amounts of hot air over the Arctic Ocean, while it can also devastate the sea ice with the destructive power of winds, rain and hail.

As above animation shows, Arctic sea ice is very thin and vulnerable at the moment. The cyclone also looks set to batter the sea ice at a time when huge amounts of ocean heat are entering the Arctic Ocean from the Atlantic and Pacific Oceans. More ocean heat looks set to be on the way. As the image below shows, sea surface temperatures around North America were as high as 33°C or 91.4°F on August 21, 2019.

The image below shows the worrying rise of Northern Hemisphere sea surface temperature anomalies from the 20th century average, with the added trend illustrating the danger that this rise will lead to Arctic sea ice collapse and large methane eruptions from the seafloor of the Arctic Ocean, further accelerating the temperature rise.

[ from an earlier post ]
The image below shows the cyclone over the Arctic Ocean on August 26, 2019.

The image below shows a close-up of the sea ice just north of the North Pole, on August 26, 2019.

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


• Climate Plan

• Arctic Sea Ice Gone By September 2019?

• July 2019 Hottest Month On Record

Saturday, October 7, 2017

Hurricane Nate Threatens New Orleans

The image below, a forecast for October 8, 2017, run on October 7, shows Hurricane Nate near New Orleans, with winds as fast as 83 mph or 134 km/h (at 850 mb) and up to 5.33 in or 135.4 mm (3-hour precipitation accumulation) of rain (at the green circle).

Early forecast also showed as much as 6.1 in or 154.9 mm of rain (3-hour precipitation accumulation) hitting the Mississippi coast.

The NOAA image below also shows the track over North America as forecast over the next few days.

Nate, the fourth major storm to strike the United States in less than two months, killed at least 30 people in Central America before entering the warm waters of the Gulf and bearing down on the U.S. South (Reuters report).

One of the biggest dangers is storm surge flooding, as illustrated by above image and the tweet below.

As the world keeps warming, hurricanes are increasingly causing damage, as also discussed in a recent post.

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


• Climate Plan

• NOAA National Hurricane Center

• The Arctic is Changing the Jet Stream - Why This Is Important

• Extreme weather is upon us

Monday, October 2, 2017

The Arctic is Changing the Jet Stream - Why This Is Important

By Sam Carana, with contributions by Jennifer Francis

Global warming is increasing the strength of hurricanes. A warmer atmosphere holds more water vapor and sea surface temperatures are rising. Both of these changes strengthen hurricanes. Steering winds may also be changing, causing unusual hurricane tracks such as Sandy's left turn into the mid-Atlantic seaboard and Harvey's stagnation over Houston. Is rapid Arctic warming playing a role?

Jennifer Francis has long been warning that global warming is increasing the likelihood of wavier jet stream patterns and more frequent blocking events, both of which have been observed. The Arctic is warming more rapidly than the rest of the world. The narrowing temperature difference between the Arctic and lower latitudes is weakening the speed at which the jet stream circumnavigates Earth and may be making the jet stream more wavy. In a 2012 study, Jennifer Francis and Stephen Vavrus warned that this makes atmospheric blocking events in the Northern Hemisphere more likely, aggravating extreme weather events related to stagnant weather conditions, such as drought, flooding, cold spells, and heat waves.

The danger was highlighted later that year, when a strong block associated with a deep jet stream trough helped steered Hurricane Sandy toward New York. In 2017, Hurricane Harvey hovered over Houston and dumped record-breaking rains (over 50 inches in some locations!), again highlighting this danger.

The jet stream separates cold air in the Arctic from warmer air farther south. A wavier jet stream transports more heat and moisture into the Arctic. This speeds up warming of the Arctic in a number of ways. In addition to warming caused by the extra heat, the added water vapor is a potent greenhouse gas, trapping more heat in the atmosphere over the Arctic, while it also causes more clouds to form that also are effective heat trappers.

As the Arctic keeps warming, the jet stream is expected to become more distorted, bringing ever more heat and moisture into the Arctic. This constitutes a self-reinforcing feedback loop that keeps making the situation worse. In conclusion, it's high time for more comprehensive and effective action to reduce the underlying culprit: global warming.

Jennifer Francis is Research Professor at the Institute of Marine and Coastal Sciences at Rutgers University, where she studies Arctic climate change and the link between the Arctic and global climates.

Jennifer has received funding from the National Science Foundation and NASA. She is a member of the American Meteorological Society, American Geophysical Union, Association for Women in Science and the Union of Concerned Scientists.


• Evidence Linking Arctic Amplification to Extreme Weather in Mid-Latitudes, by Jennifer Francis and Stephen Vavrus (March 17, 2012)

• Why Are Arctic Linkages to Extreme Weather Still Up in the Air? By Jennifer Francis (July 7, 2017)

• Amplified Arctic warming and mid‐latitude weather: new perspectives on emerging connections, by Jennifer Francis, Stephen Vavrus, Judah Cohen (May 16, 2017)

• Jennifer Francis: A New Arctic Feedback - Dec 2016 interview with Peter Sinclair (Jan 16, 2017)

• Precipitation over the Arctic - by Sam Carana (27 Jan 2017)

• Jennifer Francis - Understanding the jet stream (26 Feb 2013)

Monday, July 10, 2017

Rain Over Arctic Ocean

It's raining over the Arctic Ocean and the rain is devastating the sea ice. What are the conditions that led to this?

As has been known for a long time, energy is added to Earth due to emissions by people and this translates into a warmer troposphere with more water vapor, warmer oceans and stronger winds.

Warming is hitting the Arctic particularly hard, due to numerous feedbacks, as illustrated by the sea surface temperature anomalies image on the right.

On July 6, 2017, cyclonic winds lined up to create a 'perfect storm'. As a result, an Atmospheric River of moisture was driven through Bering Strait into the Arctic Ocean, as shown on the images below.

On July 6, 2017, 1500 UTC, winds in Bering Strait were as high as 58 km/h (36 mph) at surface level (green circle on above image left), and as high as 82 km/h (51 mph) at 850 mb (green circle on above image right).

On July 6, 2017, surface temperatures of the air in Bering Strait were as high as 8.1°C (46.5°F) (green circle on image right).

Another indication of the strength of the wind driven through Bering Strait is wave height. On July 6, 2017, waves were as high as 3.35 m or 11 ft in the Bering Strait, at the location marked by the green circle on the image on the right.

The relatively warm and moist air driven through Bering Strait by strong winds is causing rain to fall over the sea ice of the Arctic Ocean, as shown on the video and images further below.

On July 7, 2017, high air temperatures were recorded over land and over the water.

The image below shows temperatures recorded at two locations over the Mackenzie River, one of 32.6°C or 90.8°F at the mouth of the Mackenzie River and another one of 34.7°C or 94.5°F further inland. Warm water from rivers can substantially warm up the sea surface and thus melt the sea ice.

Temperature of the surface of the water was 10°C or 50.1°F where the water was pushed into the Bering Strait, while temperatures as high as 46.9°C or 116.3°F were recorded over California.

The combined impact of high temperatures, strong winds, high waves and warm river water, rain water and melt water looks set to further devastate what sea ice is left in the Arctic Ocean.

Rain can be particularly devastating. The very force at which rain strikes can fracture the sea ice where it's weak, while pools of rainwater and meltwater will form at places where the sea ice is stronger. Where fractures appear in the sea ice, warm water can reach further parts of the ice and widen the cracks.

The video below shows rain over the Arctic Ocean. The video was created with forecasts from July 3, 2017, 18:00 UTC to July 17, 2017, 00:00 UTC.

Arctic sea ice is in a terrible shape. Sea ice volume is at a record low, as indicated by the Wipneus image below showing volume anomalies from 2002.
The image below, by Torstein Viddal, shows how low the 2017 year-to-date average sea ice volume is.

An additional danger is wildfires. Due to high temperatures, wildfires have broken out near the Mackenzie River, as illustrated by the satellite image below.

Wildfires come with a lot of emissions, including soot that darkens the surface when settling down, thus further speeding up warming.

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

Friday, August 19, 2016

Storms over Arctic Ocean

Winds over the Arctic Ocean reached speeds of up to 32 mph or 52 km/h on August 19, 2016. The image below shows the Jet Stream crossing Arctic Ocean on August 19, 2016 (see map on above image for geographic reference).

The Naval Research Lab image on the right shows a forecast for sea ice speed and drift run on August 15, 2016, and valid for August 17, 2016.

These storms come at a time when the sea ice has become extremely thin, as illustrated by the Naval Research Lab sea ice thickness animation below, covering a 30-day period run on August 17, 2016, with a forecast through to August 25, 2016. The animation shows that the multi-year sea ice has now virtually disappeared.

With the sea ice in such a bad shape, strong winds can cause a rapid drop in sea ice extent, at a time when the Arctic still has quite a bit of insolation. At the North Pole, insolation will come down to zero at the time of the September 2016 Equinox.

Even more terrifying is the Naval Research Lab's Arctic sea ice thickness forecast for August 25, 2016, run on August 17, 2016, using a new Hycom model, as shown on the right.

With the thicker multi-year sea ice now virtually gone, the remaining sea ice is prone to fracture and to become slushy, which also makes it darker in color and thus prone to absorb more sunlight.

Furthermore, if strong winds keep hitting the Arctic Ocean over the next few weeks, this could push much of the sea ice out of the Arctic Ocean, along the edges of Greenland and into the Atlantic Ocean.
Strong winds are forecast to keep hitting the Arctic Ocean hard for the next week, as illustrated by the image on the right showing a forecast for August 24, 2016.

As sea ice extent falls, less sunlight gets reflected back into space and is instead absorbed by the Arctic. Once the sea ice is gone, this can contribute to a rapid rise in temperature of the surface waters.

The video below shows wind speed at 10 meters forecasts from August 25, 2016 1800 UTC to September 2, 2016 0300 UTC.

The left panel on the image below shows winds (surface) reaching speeds as high as 61 km/h or 38 mph over the Arctic Ocean (green circle), while the right panel shows winds at 250 hPa (jet stream).

As the Arctic warms faster than the rest of the world, the temperature difference between the Equator and the Arctic decreases, slowing down the speed at which the Northern Polar Jet Stream circumnavigates Earth, and making it wavier.

As a result, the Jet Stream can extend far over North America and Eurasia, enabling cold air to move more easily out of the Arctic (e.g. deep into Siberia) and at the same time enabling warm air to move more easily into the Arctic (e.g. from the Pacific Ocean). Such changes to the jet stream also enable strong winds to cross East Siberia more easily and cause stormy weather over the Arctic Ocean.

This is illustrated by the image below. The left panel shows the jet stream crossing East Siberia at speeds as high as 277 km/h or 172 mph on August 27, 2016, while at surface level cyclonic winds occurring over the Arctic ocean reached speeds as high as 78 km/h or 48 mph that day.

The right panel shows that, on that day, cold air moved deep into Central Siberia, resulting in temperatures as lows as -15.9°C or 3.5°F in Central Siberia and temperatures that were higher than they used to be over the Arctic Ocean.

[ click on image to enlarge ]
The image on the right shows surface winds (top) and winds at 250 hPa (i.e. jet stream, bottom) over the Arctic Ocean causing snow (blue) and rain (green) to fall north of Greenland (center).

Rain can have a devastating impact on the sea ice, due to kinetic energy breaking up the ice as it gets hit.

This can fragment the ice, resulting in water that is warmer than the ice to melt it both at the top and at the sides, in addition to melting that occurs at the bottom due to ocean heat warming the ice from below and melting that occurs at the top due to sunlight warming the ice from above.

Furthermore, where the rainwater stays on top of the sea ice, pools of water will form, fed by rainwater and meltwater. This will darken the surface. Melting sea ice is also darker in color and, where sea ice melts away altogether, even darker water will emerge. As a result, less sunlight is getting reflected back into space and more sunlight is instead absorbed.

The image below shows Arctic sea ice thickness (in m, nowcast, run on August 27, 2016, valid for August 28, 2016, panel left) and Arctic sea ice speed and drift (in cm per second, nowcast, run on August 27, 2016, valid for August 28, 2016, panel right).

The danger is that such storms, especially at this time of year, can push much sea ice out of the Arctic Ocean, along the edges of Greenland, into the Atlantic Ocean.

This danger grows as the sea ice gets thinner. Above image shows ice thickness (in m) nowcasts, run on August 30 and valid for August 31, for each year from 2012 to 2016.

Next to loss of snow and ice cover, another big danger in the Arctic is methane releases.

Above image shows methane levels as high as 2454 ppb on August 25, 2016 (top panel), strong releases from Alaska to Greenland on August 26, 2016 (middle panel), and mean methane levels as high as 1862 ppb on August 27, 2016 (bottom panel).

The image on the right shows high methane levels recorded at Barrow, Alaska, up to August 30, 2016.

The image below shows cyclonic winds (center left) over the Arctic Ocean on August 22, 2016.

The image below shows how little sea ice was left at locations close to the North Pole on August 25, 2016.

[ click on images to enlarge ]
The image on the right shows that Arctic sea ice extent was 4.8 million square km on August 27, 2016, according to the NSIDC.

NOAA data show that the July 2016 global land and ocean temperature was 16.67°C or 62.01°F, the highest temperature for any month on record.

The image below on the right shows July sea surface temperature anomalies (compared to the 20th century average) on the Northern Hemisphere.

This ocean heat is now being carried by the Gulf Stream toward to Arctic Ocean.

Meanwhile, the cold sea surface area that was so pronounced over the North Atlantic in 2015, is getting overwhelmed by ocean heat.

This is illustrated by the image below showing sea surface temperature anomalies on August 27, 2015 (left panel) and on August 27, 2016 (right panel).

The image below shows sea surface temperature anomalies in the Arctic (latitude 60°N-90°N) compared to 1961-1990.

The Climate Reanalyzer image below also shows sea surface temperature anomalies August 16, 2016, this time compared to 1979-2000.

The image below, from an earlier post, shows sea surface temperature anomalies on August 12, 2016, in the left-hand panel, and sea surface temperature anomalies in the right-hand panel.

Sea surface temperature and anomaly. Anomalies from +1 to +2 degrees C are red, above that they turn yellow and white
Above image also shows that on August 12, 2016, sea surface temperatures near Svalbard (at the location marked by the green circle) were as high as 18.9°C or 65.9°F, an anomaly of 13.6°C or 24.4°F.

As said above, changes to the Jet Stream enable warm air to move more easily into the Arctic Ocean and cold air to move more easily out of the Arctic Ocean. Where seas are shallow, a surface temperature rise can quickly warm up water all the way down to the Arctic ocean seafloor, where it can destabilize methane hydrates contained in sediments.

This could make that huge amounts of methane get released from the seafloor. Given that many of the seas in Arctic are very shallow, much of this methane can enter the atmosphere without getting broken down in the water, resulting in huge additional warming, especially over the Arctic. As discussed in an earlier post, this could contribute to a global temperature rise of over 10°C or 18°F by the year 2026.

One of the people who has been warning about these dangers for many years is Professor Peter Wadhams, whose new book A Farewell to Ice was recently launched (256 pages, published September 1, 2016).

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


 Wildfires in Russia's Far East

 Climate Plan

 Rain Storms Devastate Arctic Ice And Glaciers

 High Temperatures in the Arctic

 Arctic Sea Ice Getting Terribly Thin

 A Global Temperature Rise Of More than Ten Degrees Celsius By 2026?

 A Farewell to Ice, by Peter Wadhams

Thursday, August 15, 2013

Arctic Sea Ice in Free Fall

Arctic Sea Ice has declined dramatically recently. The recent image below, by the Danish Meteorological Institute, shows the decline in extent over the past few days, with extent calculated by including all areas with ice concentration higher than 30%.

As the above image shows, sea ice extent (30%+ concentration) is now lower than any other year, except 2007 and 2012. Moreover, the sharp decline looks set to continue.

Ice volume and concentration have dropped dramatically, partly as a result of the cyclone that hit the Arctic Ocean a few days ago. The eye of the cyclone is still visible almost exactly above the North Pole on the Naval Research Laboratory image below on the right, where sea ice concentration appears to form a circle.

The sea ice looks set for an all-time record low; all this thin ice looks set to disappear over the next few weeks.

The graph below, also by the Danish Meteorological Institute, calculates sea ice extent by including all areas with 15% or more ice concentration.
The above graph also shows a steep recent descent, although not as pronounced as in the graph at the top that includes spots with 30% or more ice concentration. The graph at the top better illustrates recent drops in ice concentration from, say, 40% to 20%, which can occur quite abruptly due to the impact of a cyclone. 

The Danish Meteorological Institute has meanwhile produced a more recent version of the graph based on spots with 30% or more ice concentration (added below).

The above graph shows an August 15 extent that appears to be back in line with the earlier trend. At first glance, it may appear as if the sea ice has largely recovered from the impact of three cyclones that have hit the Arctic Ocean over the past two months. 

However, these cyclones are likely to have contributed to the appearance and persistence of thin spots in the ice close to the North Pole. This phenomenon was earlier described in posts such as Thin Spots developing in Arctic Sea Ice

The conclusion remains the same as the one drawn then in that post, i.e. that for years, observation-based projections have been warning about Arctic sea ice collapse within years, with dire consequences for the Arctic and for the world at large.

Cyclones can speed up this 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 (not northerly, as she stated). 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."
Hopefully, more people will realize the urgency of the situation and realize the need for a comprehensive and effective plan of action as described here.