Arctic News: 2020 Siberian Heatwave continues

Thursday, June 18, 2020

2020 Siberian Heatwave continues

Very high temperatures hit Northern Europe and Eastern Siberia near the Arctic Ocean on June 18, 2020. This is a continuation of the heatwave that hit Siberia in May 2020.

The image below, from an earlier post, shows temperature anomalies that were forecast to be at the high end of the scale over Siberia on May 22, 2020, 06:00 UTC, i.e. 30°C or 54°F higher than 1979-2000. At the same time, cold temperatures were forecast for much of eastern Europe.

What enables such a strong heatwave to develop is that the Jet Stream is getting more wavy as the temperature difference between the North Pole and the Equator is narrowing, causing both hot air to move up into the Arctic (red arrow) and cold air to descend out of the Arctic (blue arrow).

On June 19, 2020, at 03:00 UTC, a temperature of 33.2°C or 91.8°F was recorded in Siberia near the Arctic Ocean (green circle).

The image below shows a temperature forecast of 33.5°C or 92.2°F in Siberia near the Arctic Ocean on June 20, 2020, at 03:00 UTC (green circle).

The image below is a forecast for June 23, 2020, showing how a distorted Jet Stream enables cold air to move down into Russia, while at the same time enabling hot air to move north over Scandinavia and Siberia, near the Arctic Ocean.

The image below is a forecast for June 25, 2020, showing the coast of Siberia near the Arctic Ocean getting hit by temperature anomalies at the top end of scale, i.e. 30°C or 54°F higher than 1979-2000.

The image on the right is an update, showing how wavy the Jet Stream turned out to be on June 25, 2020.

This facilitates hot air getting carried north over Western Europe, East Siberia and through the Bering Strait, while cold air is moving south over the European part of Russia. Blocking patterns that prolong such a situation go hand in hand with a more wavy Jet Stream.

Record High Temperature in Arctic

The image below shows that temperatures in Siberia were as high as 40°C or 104°F at 5 cm above the ground on June 21, 2020, at 3 pm, the Ventusky.com map shows.

This indicates how much the soil of what once was permafrost is heating up. At 2 m above ground level, i.e. the default height for air temperature measurements, it was 30°C or 86°F, as the image below shows. The location marked by the star is at 71°28' North latitude and 142°59' East longitude, and at and altitude of 13 m.

The day before, Verkhoyansk in Siberia reached a temperature of 38°C or 100.4°F on June 20, 2020, a record high for the Arctic. Verkhoyansk is located at 67°55′ North latitude.

Both locations are well north of the Arctic Circle that - at 66°30′ N - constitutes the southern limit of the area within which, for one day or more each year, the Sun does not set (about June 21) or rise (about December 21).

High Ocean Temperatures

The heatwave is heating up the sea surface of the East Siberian Arctic Shelf (ESAS), as illustrated by above image. The ESAS is quite shallow, making that heat can quickly reach the seafloor.

Additionally, the heatwave is heating up rivers that carry large amounts of hot water into the Arctic Ocean.

The image on the right shows sea surface temperatures in the Bering Strait as high as 18.9°C or 66.02°F on June 22, 2020.

The nullschool.net website shows that sea surface temperatures in the Bering Strait were as high as 16.1°C or 60.9°F on June 20, 2020, in the Bering Strait (in Norton Sound, Alaska), i.e. 15.1°C or 27.2°F hotter than 1981-2011.

In summary, the Arctic Ocean is heating up in a number of ways:

- Sea currents are moving hot water from the Pacific Ocean into the Arctic Ocean. Similarly, sea currents are moving hot water from the Atlantic Ocean into the Arctic Ocean.

- The Siberian heatwave is heating up the sea surface of the ESAS.

- The heatwave is heating up rivers that carry large amounts of hot water into the Arctic Ocean.

- Numerous feedbacks can speed up the temperature rise, such as changes to the jet stream that can prolong heatwaves and make them more intense.

The rising temperatures result in record low Arctic sea ice volume, as illustrated by the image on the right and as also discussed in an earlier post.

Heat threatens to destabilize methane hydrates

As discussed in earlier posts such as this one, this heat threatens to destabilize methane hydrates contained in sediments at the seafloor of the Arctic Ocean.

As the panel on the left shows, sea surface temperatures in the Bering Strait were as much as 15.1°C or 27.2°F hotter than 1981-2011 on June 20, 2020 (in Norton Sound, Alaska, at the green circle).

The bathymetry map in the right panel of above image shows how shallow seas in the Arctic Ocean can be. The water over the ESAS is quite shallow, making that the water can warm up very quickly during summer heat peaks and heat can reach the seafloor, which comes with the risk that heat will penetrate cracks in sediments at the seafloor. Melting of ice in such cracks can lead to abrupt destabilization of methane hydrates contained in sediments.

Large abrupt methane releases will quickly deplete the oxygen in shallow waters, making it harder for microbes to break down the methane, while methane rising through waters that are shallow can enter the atmosphere very quickly.

The situation is extremely dangerous, given the vast amounts of methane present in sediments in the ESAS, given the high global warming potential (GWP) of methane following release and given that over the Arctic there is very little hydroxyl in the air to break down the methane.

[ from earlier post ]

Ominously, the MetOp-1 satellite recorded a peak methane level of 2847 parts per billion on the afternoon of June 24, 2020, at 469 mb.

The next day, on the afternoon of June 25, 2020, MetOp-1 recorded a mean methane level of 1903 parts per billion at 293 mb. The 469 mb pressure level on above image corresponds with altitude of 6,041 m or 19,820 feet on the conversion table below. The 293 mb mean on the image below corresponds with a much higher altitude, i.e. 9,318 m or 30,570 feet on the conversion table below.

Methane reaching the Stratosphere

The MetOp satellites typically record the highest annual mean methane level in September. The image below, from an earlier post, shows that on the afternoon of September 30, 2019, the MetOp-1 satellite recorded the highest mean methane level, i.e. 1914 parts per billion, at 293 mb.

Above image shows that methane levels have risen most at higher altitude over the years. As discussed in an earlier post, methane eruptions from the Arctic Ocean can be missed by measuring stations that are located on land and that often take measurements at low altitude, thus missing the methane that rises in plumes from the Arctic Ocean. Since seafloor methane is rising in plumes, it hardly shows up on satellite images at lower altitude either, as the methane is very concentrated inside the area of the plume, while little or no increase in methane levels is taking place outside the plume. Since the plume will cover less than half the area of one pixel, such a plume doesn't show up well at low altitudes on satellite images.

Over the poles, the Troposphere doesn't reach the heights it does over the tropics. At higher altitudes, methane will follow the Tropopause, i.e. the methane will rise in altitude while moving closer to the Equator.

Methane rises from the Arctic Ocean concentrated in plumes, pushing away the aerosols and gases that slow down the rise of methane elsewhere, which enables methane erupting from the Arctic Ocean to rise straight up fast and reach the stratosphere.

The rise of methane at these high altitudes is very worrying. Once methane reaches the stratosphere, it can remain there for a long time. The IPCC in 2013 (AR5) gave methane a lifetime of 12.4 years. The IPCC in 2001 (TAR) gave stratospheric methane a lifetime of 120 years, adding that less than 7% of methane did reach the stratosphere.

Further Feedbacks

Furthermore, the Siberian heatwave is also threatening to trigger forest fires that can cause huge amounts of emissions, including black carbon that can settle on the snow and ice cover, further speeding up its demise and causing albedo changes that result in a lot more heat getting absorbed in the Arctic, instead of getting reflected back into space as was previously the case. This is illustrated by the image below showing forest fires in East Siberia on June 19, 2020.