Climate Science News

15-21 May, 2017 week

AVISO Climate Change News - Tue, 2017-05-23 07:59
L'Antarctique verdit rapidement sous l'effet du changement climatique (Le Parisien, 2017/05/18)
VIDEO. Découverte d'un corail capable de résister au changement climatique (L’Express, 2017/05/18)
Dans l'océan Pacifique, découverte d'une île déserte aux déchets (Sciences et Avenir, 2017/05/17)
Mission océan Austral : cap vers le grand Sud (Le Monde, 2017/05/17)
Réchauffement climatique : les régions polaires sous la loupe de l’ONU (Good Planet, 2017/05/16)
On line availability of articles depends on the Newspaper/magazine. We can't thus certify that above articles will be freely and permanently available.

Categories: Climate Science News

8-14 May, 2017 week

AVISO Climate Change News - Thu, 2017-05-18 05:21
Réchauffement climatique : les régions polaires sous la loupe de l'ONU (Sciences et Avenir, 2017/05/15)
Plastique dans l'océan : Ocean Clean-Up accélère (Sciences et Avenir, 2017/05/12)
Climat : la Terre se réchauffera de 1,5°C d'ici une dizaine d'années (Le Figaro, 2017/05/12)
Tous les indicateurs du réchauffement climatique sont au rouge (Le Monde, 2017/05/09)
Une "banquise" de bouteilles en plastique recouvre le fleuve Congo à Kinshasa (Les Observateurs, 2017/05/09)
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Categories: Climate Science News

May 2017: Ocean mirror the deep

AVISO Climate Change News - Thu, 2017-05-11 07:45
With more and more altimetry data available, high-precision computation of the Mean Sea Surface is...
Categories: Climate Science News

1-7 May, 2017 week

AVISO Climate Change News - Thu, 2017-05-11 06:28
Et l'herbe devint plus verte : les surprenants effets du dérèglement climatique en Arctique (Atlantico, 2017/05/07)
El Nino de retour cette année ?  (News Environnement, 2017/05/06)
Meet an expert oceanographer (ESA, 2017/05/05)
Pollution aux plastiques : elle atteint désormais l'océan Arctique (Science et Vie, 2017/05/04)
Réchauffement climatique: la hausse du niveau des mers s'accélère (Sud Ouest, 2017/05/03)
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Categories: Climate Science News

17-30 April 2017 week

AVISO Climate Change News - Tue, 2017-05-09 02:55
Pour la première fois, une accélération de la montée des océans est observée (Le Monde, 2017/04/29)
Climat : possible retour d'El Niño dès 2017 (Le Figaro, 2017/04/28)
Predicting the movement and impacts of microplastic pollution (Terra Daily, 2017/04/27)
Manchots: les chercheurs appellent à mieux protéger l'Antarctique (La Dépêche, 2017/04/25)
Réchauffement climatique : 146 000 rennes menacés de mort (Le Parisien, 2014/04/24)
Océan Arctique : découverte d’une importante zone d’accumulation des déchets plastiques au nord de l’Europe (AlphaGalileo, 2017/04/20)
Réchauffement climatique: La fonte rapide d'un glacier assèche une rivière canadienne (20 minutes, 2017/04/19)
On line availability of articles depends on the Newspaper/magazine. We can't thus certify that above articles will be freely and permanently available.

Categories: Climate Science News

17-30 April 2017 week

AVISO Climate Change News - Tue, 2017-05-09 02:55
Pour la première fois, une accélération de la montée des océans est observée (Le Monde, 2017/04/29)
Climat : possible retour d'El Niño dès 2017 (Le Figaro, 2017/04/28)
Predicting the movement and impacts of microplastic pollution (Terra Daily, 2017/04/27)
Manchots: les chercheurs appellent à mieux protéger l'Antarctique (La Dépêche, 2017/04/25)
Réchauffement climatique : 146 000 rennes menacés de mort (Le Parisien, 2014/04/24)
Océan Arctique : découverte d’une importante zone d’accumulation des déchets plastiques au nord de l’Europe (AlphaGalileo, 2017/04/20)
Réchauffement climatique: La fonte rapide d'un glacier assèche une rivière canadienne (20 minutes, 2017/04/19)
On line availability of articles depends on the Newspaper/magazine. We can't thus certify that above articles will be freely and permanently available.

Categories: Climate Science News

Warm Arctic, cool continents

NSIDC Artic Sea Ice News - Wed, 2017-05-03 12:00

Arctic sea ice extent for April 2017 tied with April 2016 for the lowest in the satellite record for the month. Warm weather conditions and lower-than-average sea ice extent prevailed over the Pacific side of the Arctic, while relatively cool conditions were the rule in northern Europe and eastern North America. In the Southern Hemisphere, Antarctic sea ice extent remained lower than average.

Overview of conditions Figure 1. Arctic sea ice extent for April 2017 was 13.83 million square kilometers (5.34 million square miles). The magenta line shows the 1981 to 2010 average extent for that month.

Figure 1. Arctic sea ice extent for April 2017 was 13.83 million square kilometers (5.34 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Arctic sea ice extent for April 2017 averaged 13.83 million square kilometers (5.34 million square miles), and tied with April 2016 for the lowest April extent in the 38-year satellite record. The April 2017 extent is 1.02 million square kilometers (394,000 square miles) below the April 1981 to 2010 long-term average. The largest reductions in ice extent through the month occurred on the Pacific side of the Arctic, within the Bering Sea and the Sea of Okhotsk. Little change in extent occurred in the Atlantic sector of the Arctic.

Conditions in context Figure 2a. The graph above shows Arctic sea ice extent as of May 2, 2017, along with daily ice extent data for four previous years. 2017 is shown in blue, 2016 in green, 2015 in orange, 2014 in brown, and 2013 in purple, and 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data.

Figure 2a. The graph above shows Arctic sea ice extent as of May 2, 2017, along with daily ice extent data for five previous years. 2017 is shown in blue, 2016 in green, 2015 in orange, 2014 in brown, and 2013 in purple, and 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

Figure 2b. These figures show April 2017 Arctic air temperature difference at the 925 hPa level (about 2,500 feet above sea level) in degrees Celsius (left) and sea level pressure (right). Yellows and reds indicate higher than average temperatures and pressure; blues and purples indicate lower than average temperatures and pressure.

Figure 2b. These figures show April 2017 differences from average for Arctic air temperatures at the 925 hPa level (about 2,500 feet above sea level) in degrees Celsius (left) and for sea level pressure (right). Yellows and reds indicate higher than average temperatures and pressure; blues and purples indicate lower than average temperatures and pressure.

Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Division
High-resolution image

Figure 2c. These maps show Arctic sea ice motion for April 13 to 15, 2017, which is representative of the general pattern seen throughout the month. Black arrows represent sea ice drift. The purple arrows represent "filled" values, data gaps that have been interpolated from surrounding data.

Figure 2c. These maps show Arctic sea ice motion for April 13 to 15, 2017, which is representative of the general pattern seen throughout the month. Black arrows represent sea ice drift. The purple arrows represent “filled” values, data gaps that have been interpolated from surrounding data.

Credit: EUMETSAT
High-resolution image

The decline in ice extent through the month was fairly steady, at a rate similar to what was observed over the previous two Aprils (2016 and 2015). Throughout the month, sea ice extent was either at daily record lows for the period of satellite observations, or within 100,000 square kilometers (~38,600 square miles) of record low values. At the end of the month, extent was below average in the Barents Sea, the Sea of Okhotsk, and the western Bering Sea, similar to the pattern seen in March. Despite fairly warm conditions, sea ice extent was slightly above average in Baffin Bay.

Unusually warm conditions were observed across the Pacific side of the Arctic Ocean, with temperatures at the 925 hPa level (about 2,500 feet above sea level) north of the Bering Strait ranging from 6 to 8 degrees Celsius (11 to 14 degrees Fahrenheit) above the 1981 to 2010 average. Western Alaska and easternmost Siberia also saw warm conditions. However, below average temperatures ruled across a broad swath of northern Canada. Of particular note, cooler-than-average conditions also prevailed over Greenland, leading to relatively little surface melting on the ice sheet in April (unlike the preceding two years).

The overall temperature pattern is consistent with the average sea level pressure pattern for the month, which had large areas of low and higher-than-average pressure in the Eastern and Western Hemispheres, respectively. This pattern produces a cross-Arctic airflow, with southerly winds from the Bering Sea blowing into the Chukchi Sea and central Arctic, and cool winds blowing from the north over Scandinavia and other areas of northern Europe. This cross-Arctic wind pattern is also evident in the sea ice motion field for April 2017. Sea ice motion is determined by tracking patterns in the sea ice in both visible imagery and in passive microwave data from satellites.

April 2017 compared to previous years Figure 3a. Monthly April ice extent for 1979 to 2017 shows a decline of 2.6 percent per decade.

Figure 3a. Monthly April ice extent for 1979 to 2017 shows a decline of 2.6 percent per decade.

Credit: National Snow and Ice Data Center
High-resolution image

Figure 3b. This shows April 2017 Arctic sea ice concentration anomalies (left) and Arctic sea ice concentration trends (right).

Figure 3b. These images show April 2017 Arctic sea ice concentration anomalies (left) and Arctic sea ice concentration trends (right). Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

The linear rate of decline for April is 38,000 square kilometers (15,000 square miles) per year, or 2.6 percent per decade.

Declining ice extent in the Barents Sea, Sea of Okhotsk, and off the coast of southeastern Greenland is a part of the long-term pattern of sea ice decline. Below-average ice extent in the western Bering Sea has to date not been a part of the long-term trend for April.

A report from the field Figure 4. This photo shows broken up sea ice and some multi-year floes at Alert, on the northern tip of Ellesmere Island, Canada. A researcher and a Twin Otter aircraft are obscured in the background.

Figure 4. This photo shows broken up sea ice and some multi-year floes at Alert, on the northern tip of Ellesmere Island, Canada on April 2017. A researcher and a Twin Otter aircraft are obscured in the background.

Credit: J. Stroeve/NSIDC
High-resolution image

NSIDC scientist Julienne Stroeve continued her Arctic field work into early April, moving from Cambridge Bay, Canada to Alert in Ellesmere Island. In Alert, Stroeve focused on sampling ice thickness and snow pack characteristics along a CryoSat-2 flight track within the Lincoln Sea. This is an area between northernmost Greenland and Ellesmere Island where thick, old ice remains. The scientists flew by Twin Otter each day, out onto the sea ice between latitudes 83°N and 87.1°N. The field campaign was also supported by an aircraft from the British Antarctic Survey carrying a Ka band radar, LiDAR, and a broadband radiometer. A NASA Operation IceBridge flight also flew over the same track.

The group noted that the ice was unusually broken up and reduced to rubble, with few large multi-year floes, forcing the pilots to land on refrozen leads that at times were only 70 centimeters (28 inches) thick. Pilots remarked that they had never seen the ice look like this. Preliminary estimates suggest mean thicknesses ranging from 2 to 3.4 meters (6.6 to 11 feet), with the thickest ice found between an ice bridge in the Lincoln Sea and mobile pack ice to the north. Modal thickness, a representation of thermodynamically-grown level ice, ranged between 1.8 and 2.9 meters (6 and 10 feet), including 0.25 to 0.4 meters (10 to 16 inches) of snow. Second- and first-year modal ice thicknesses ranged between 1.8 and 1.9 meters (6 and 6.2 feet), about 0.2 meters (8 inches) thinner than previous airborne measurements indicated. More details can be found at the European Space Agency’s Campaigns at Work blog.

Arctic sea ice age Figure 5. These maps shows 2016 (top left) and 2017 (top right) Arctic sea ice age for the end of March and the time series of percent coverage for the Arctic Ocean (bottom).

Figure 5. These maps shows 2016 (top left) and 2017 (top right) Arctic sea ice age for the end of March and the time series of percent coverage for the Arctic Ocean (bottom).

Credit: National Snow and Ice Data Center, courtesy M. Tschudi, C. Fowler, J. Maslanik, R. Stewart/University of Colorado Boulder; W. Meier/NASA Cryospheric Sciences
High-resolution image

Sea ice age is a proxy for ice thickness, with older ice generally meaning thicker ice. Though ice can pile up into rubble fields when the motion of the ice pushes up against the coast or thicker ice, level ice generally increases in thickness as it ages through more winter freeze cycles. Thus, ice age is a reasonable indicator of the sea ice thickness.

At the end of March, ice age data show only a small remaining coverage of old (5+ years) ice. Since 2011, the oldest ice has comprised less than 5 percent of the total ice cover. During the mid-1980s, such ice made up nearly a third of the ice.

The next oldest ice category, four-year-old ice has also dropped from about 8 to 10 percent to less than 5 percent. The coverage of intermediate age ice categories (2- and 3-year-old ice) has stayed fairly consistent through time. The oldest ice has essentially been replaced by first-year ice (ice that has formed since the previous September). First-year-ice has risen from 35 to 40 percent of the Arctic Ocean’s ice cover during the mid-1980s to about 70 percent now.

Comparison of March 2016 conditions to this year shows a similar percentage coverage for the different ice ages. However, the spatial distribution is different. In March 2016, bands of the oldest ice extended through the Beaufort Sea and into the Chukchi, with scattered patches north of the Canadian Archipelago and Greenland. This year, the oldest ice is consolidated against the coast of Greenland and the archipelago except for a short arm extending north to the region around the pole. Most of the third year ice is between Fram Strait and the pole, which means it is likely to exit the Arctic Ocean during the coming months.

Antarctic ice extent low, but not lowest Figure 6. The graph above shows Antarctic sea ice extent as of May 2, 2017, along with daily ice extent data for four previous years. 2017 is shown in blue, 2016 in green, 2015 in orange, 2014 in brown, and 2013 in purple, and 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data.

Figure 6. The graph above shows Antarctic sea ice extent as of May 2, 2017, along with daily ice extent data for four previous years. 2017 is shown in blue, 2016 in green, 2015 in orange, 2014 in dashed brown, and 2013 in purple. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

Antarctic sea ice grew at a slightly faster-than average pace in April, but was still setting daily record lows until about April 10, after which extent rose above the 1980 ice extent. The April 2017 sea ice extent is lower than average in the Amundsen Sea and slightly lower than average in the Ross Sea and easternmost Weddell Sea. However, an area of above average extent is present in the north-central Weddell. Temperatures on the continent were above average over West Antarctica and western Wilkes Land, and considerably below average over the central Weddell sea.

Categories: Climate Science News

[SSALTO/DUACS products] redelivery of gridded geostrophic currents products on 19 and 20/04

AVISO Climate Change News - Thu, 2017-04-20 08:16
All the files have been redelivered today at 11h UTC. We are sorry for the inconvenience this has caused.
Categories: Climate Science News

[SSALTO/DUACS products] redelivery of gridded geostrophic currents products on 19 and 20/04

AVISO Climate Change News - Thu, 2017-04-20 08:16
All the files have been redelivered today at 11h UTC. We are sorry for the inconvenience this has caused.
Categories: Climate Science News

9-16 April, 2017 week

AVISO Climate Change News - Thu, 2017-04-20 06:32
Réchauffement climatique : l'effrayant scénario d'une Terre sans glace (L’Obs, 2017/04/15)
La Méditerranée : un laboratoire de solutions Océan et Climat (Le Monde, 2017/04/11)
Le réchauffement climatique va modifier l’amplitude des marées en Europe (Le Monde, 2017/04/11)
Changement climatique : menace sur la baie du Mont-Saint-Michel (Le Parisien, 2017/04/11)
On line availability of articles depends on the Newspaper/magazine. We can't thus certify that above articles will be freely and permanently available.

Categories: Climate Science News

9-16 April, 2017 week

AVISO Climate Change News - Thu, 2017-04-20 06:32
Réchauffement climatique : l'effrayant scénario d'une Terre sans glace (L’Obs, 2017/04/15)
La Méditerranée : un laboratoire de solutions Océan et Climat (Le Monde, 2017/04/11)
Le réchauffement climatique va modifier l’amplitude des marées en Europe (Le Monde, 2017/04/11)
Changement climatique : menace sur la baie du Mont-Saint-Michel (Le Parisien, 2017/04/11)
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Categories: Climate Science News

2-9 April, 2017 week

AVISO Climate Change News - Thu, 2017-04-13 01:05
La Grande Barrière de corail ne se remettra pas du réchauffement des eaux (Le Monde, 2017/04/10)
Plongée dans l’océan plastique (Libération, 2017/04/09)
L’Arctique, bombe à retardement du climat (L’Alsace, 2017/04/08)
Pourquoi l'année 2017 est cruciale pour la sauvegarde des océans (Le Figaro, 2017/04/07)
Les expéditions scientifiques se bousculent au chevet de l’océan (Le Monde, 2017/04/05)
On line availability of articles depends on the Newspaper/magazine. We can't thus certify that above articles will be freely and permanently available.
Categories: Climate Science News

2-9 April, 2017 week

AVISO Climate Change News - Thu, 2017-04-13 01:05
La Grande Barrière de corail ne se remettra pas du réchauffement des eaux (Le Monde, 2017/04/10)
Plongée dans l’océan plastique (Libération, 2017/04/09)
L’Arctique, bombe à retardement du climat (L’Alsace, 2017/04/08)
Pourquoi l'année 2017 est cruciale pour la sauvegarde des océans (Le Figaro, 2017/04/07)
Les expéditions scientifiques se bousculent au chevet de l’océan (Le Monde, 2017/04/05)
On line availability of articles depends on the Newspaper/magazine. We can't thus certify that above articles will be freely and permanently available.
Categories: Climate Science News

Another record, but a somewhat cooler Arctic Ocean

NSIDC Artic Sea Ice News - Tue, 2017-04-11 08:21

Arctic sea ice extent for March 2017 was the lowest in the satellite record for the month. The decline in ice extent has been uneven since the seasonal maximum was reached on March 7, 2017, with a modest period of expansion towards the end of the month.

Overview of conditions extent map

Figure 1. Arctic sea ice extent for March 2017 was 14.43 million square kilometers (5.57 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Arctic sea ice extent for March 2017 averaged 14.43 million square kilometers (5.57 million square miles), the lowest March extent in the 38-year satellite record. This is only 60,000 square kilometers (23,000 square miles) below March 2015, the previous lowest March extent, and 1.17 million square kilometers (452,000 square miles) below the March 1981 to 2010 long-term average. This month continues the record low conditions seen since October 2016.

Conditions in context timeseries graph

Figure 2a. The graph above shows Arctic sea ice extent as of April 9, 2017, along with daily ice extent data for five previous years. 2017 to 2016 is shown in blue, 2015 to 2016 in green, 2014 to 2015 in orange, 2013 to 2014 in brown, 2012 to 2013 in purple, and 2011 to 2012 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

air temperature plot

Figure 2b. The plot shows Arctic air temperature differences at the 925 hPa level (about 2,500 feet above sea level) in degrees Celsius for March 2017. Yellows and reds indicate temperatures higher than the 1981 to 2010 average; blues and purples indicate temperatures lower than the 1981 to 2010 average.

Credit: NSIDC courtesy NOAA/ESRL Physical Sciences Division
High-resolution image

sea level pressure plot

Figure 2c. The plot shows Arctic sea level pressure (in millibars) for March 2017 expressed as departures from average conditions. The dominant feature is a large area of below average pressure covering most of the Arctic Ocean.

Credit: NSIDC courtesy NOAA/ESRL Physical Sciences Division
High-resolution image

The decline in sea ice extent following the March 2017 seasonal maximum was interrupted by a brief period of expansion from about March 11 to 15, a decline extending through about March 26, then another period of growth through the end of the month into early April. On April 4th, the extent was greater than on the same day in 2016. This type of behavior is not unusual for this time of year when declines in extent in warmer, lower latitudes can be countered by periods of expansion in the still-cold higher latitudes. Shifts in wind patterns also lead to variability. Regions that experienced slight ice advance were at the end of the month in the Barents Sea and in the Bering Sea. Nevertheless, by early April, extent remained below average in the Barents Sea and in the Sea of Okhotsk and the western Bering Sea. Interestingly, ice extended further south than usual in the eastern Bering Sea.

March saw continued warmth over the Arctic Ocean. The warmest conditions for March 2017 as compared to average were over Siberia. While temperatures were still well above average along the Russian coastal seas (6 to 7 degrees Celsius, or 11 to 13 degrees Fahrenheit), those over the northern North Atlantic and the Canadian Arctic Archipelago were near average.

The dominant feature of the sea level pressure field for March 2017 was an area of below average pressure covering most of the Arctic Ocean. Locally, pressures were more than 15 millibars below the 1981 to 2010 average. This pattern points to a continuation of the stormy conditions that prevailed over the past winter and is broadly consistent with the positive phase of the Arctic Oscillation, a large-scale mode of climate variability. When the Arctic Oscillation is in its positive phase, sea level pressure is below average over the Arctic Ocean. The Arctic Oscillation has generally been in a positive phase since December. The unusually high Siberian temperatures for March 2017 are consistent with persistent winds from the south and east along the southern side of the low pressure.

March 2017 compared to previous years trend graph

Figure 3. Monthly March ice extent for 1979 to 2017 shows a decline of 2.74 percent per decade.

Credit: National Snow and Ice Data Center
High-resolution image

The linear rate of decline for March is 42,700 square kilometers (16,500 square miles) per year, or 2.74 percent per decade.

Report from the field research photo

Figure 4. The team prepares to measure snow thickness over sea ice in Cambridge Bay, Canada on April 5, 2017, during an AltiKa field validation campaign. NSIDC researcher Andrew Barrett is in a red jacket; Julienne Stroeve holds a magna probe.

Credit: Isobel Lawrence
High-resolution image

As of the publication of this post, NSIDC scientists Julienne Stroeve and Andrew Barrett are in Cambridge Bay, Canada on a satellite validation campaign. Efforts focus on ground measurements of snow depth over sea ice, ice thickness, and snow structure in order to validate the joint French/Indian AltiKa Ka band radar altimeter. Coincident aircraft Ka band and LiDAR measurements allow researchers to connect measurements on the ground with those made by the satellite. Air temperatures have ranged from -20 to -5 degrees Celsius (-4 to 23 degrees Fahrenheit), with wind chills from -40 to -20 degrees Celsius (-40 to -4 degrees Fahrenheit). Dr. Stroeve will then join another field campaign operating out of Alert, Canada for further validation of AltiKa and CryoSat2 over the Lincoln Sea.

Arctic sea ice thickness sea ice volume plot

Figure 5. The graph shows sea ice volume from the PIOMAS model/observations for each year from 2010 through March 2017, and the 1979 to 2016 average (black line) and one (dark gray) and two (light gray) standard deviation ranges.

Credit: NSIDC courtesy University of Washington Polar Science Center
High-resolution image

A key early indicator for the upcoming melt season is the thickness of the sea ice. An assessment of available information suggests a fairly thin ice cover, not surprising given the warm temperatures over much of the Arctic Ocean during the winter.

Satellite data from the European Space Agency (ESA) CryoSat-2 radar altimeter, which is processed into sea ice thickness estimates at the University College London’s Center for Polar Observing and Modeling (CPOM) indicates ice along much of the Siberian coast with thicknesses of 1.5 to 2.0 meters (4.9 to 6.6 feet) or less. This is not atypical for seasonal ice; however this band of <2.0 meters of ice covers a much larger region and extends much farther north than it used to—well north of 80 degrees N latitude on the Atlantic side of the Arctic. NASA’s Operation IceBridge has also been collecting data over the past month. That data will not be available for a few weeks; a key focus of some flights has involved collaboration with ESA to collect coincident data with CryoSat-2 to help validate the satellite estimates.

Another way to estimate thickness and total ice volume is with a combination of observations and a model, which is done by the University of Washington Polar Science Center’s University of Washington Polar Science Center’s Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS). The model uses observed sea ice concentration fields to constrain the model and estimates thickness and total volume via physical simulations in the model. It shows that sea ice volume has been at record low levels throughout 2017 so far (Figure 5).

Sea ice loss and Atlantic layer heat

For many years, scientists have pondered how much of the sharp decline in summer sea ice extent and volume is due to “top down” forcing—a warmer atmosphere leading to more summer melt and less winter growth, versus “bottom up” forcing, in which ocean heat is brought to bear on the underside of the ice. There is a great deal of heat in the Arctic Ocean from waters that are imported from the Atlantic. As fairly warm and salty Atlantic water enters the Arctic Ocean it dives underneath the relatively fresh Arctic Ocean surface layer. Because the fresh surface layer has a fairly low density, the vertical structure of the Arctic Ocean is very stable. As such, it is hard to mix this Atlantic heat upwards to melt ice or keep it from forming in the first place. However, new work by an international team led by Igor Polyakov of the University of Alaska Fairbanks provides strong evidence that Atlantic layer heat is now playing a prominent role in reducing winter ice formation in the Eurasian Basin, which is manifested as more summer ice loss. According to their analysis, the ice loss due to the influence of Atlantic layer heat is comparable in magnitude to the top down forcing by the atmosphere.

Antarctic ice extent low, but on the rise antarctic timeseries plot

Figure 6. The graph above shows Antarctic sea ice extent as of April 9, 2017, along with daily ice extent data for four previous years. 2017 is shown in blue, 2016 in green, 2015 in orange, 2014 in brown, and 2013 in purple. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

Following the record-low seasonal sea ice minimum, Antarctic sea ice extent has sharply risen, but extent is still far below average, and set daily record low values throughout the month of March. Regionally, sea ice recovered to near average conditions in the Weddell Sea and around much of the coast of East Antarctica. The primary region of below average extent was in the Ross, Amundsen, and Bellingshausen Sea regions, as has been the case throughout the spring and summer. This appears to be related to warmer-than-average sea surface temperatures.

Additional reading

Polyakov, I., A.V. Pnyushkov, M.B. Alkire, I.M. Ashik, T.M. Baumann, E.C. Carmack and 10 others. 2017. Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean. Science, doi:10.1126/science.aai8204.

 

 

Categories: Climate Science News

27 march - 2 April, 2017 week

AVISO Climate Change News - Thu, 2017-04-06 07:35
Satellites reveal bird habitat loss in California (Space Daily, 2017/03/29)
Climat : "Nous venons d'observer un évènement inédit en Antarctique" (Sciences et Avenir, 2017/03/28)
CryoSat reveals Antarctica in 3D (ESA, 2017/03/24)
On line availability of articles depends on the Newspaper/magazine. We can't thus certify that above articles will be freely and permanently available.

Categories: Climate Science News

27 march - 2 April, 2017 week

AVISO Climate Change News - Thu, 2017-04-06 07:35
Satellites reveal bird habitat loss in California (Space Daily, 2017/03/29)
Climat : "Nous venons d'observer un évènement inédit en Antarctique" (Sciences et Avenir, 2017/03/28)
CryoSat reveals Antarctica in 3D (ESA, 2017/03/24)
On line availability of articles depends on the Newspaper/magazine. We can't thus certify that above articles will be freely and permanently available.

Categories: Climate Science News

[Jason-2] Nominal production in Ssalto/Duacs products

AVISO Climate Change News - Wed, 2017-04-05 01:01
The Jason-2 mission has been reintegrated in the Ssalto/Duacs processing system since April 4th, after validation. It includes data from 30/03/2017 in the “j2n” dataset.
Categories: Climate Science News
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