Climate Science News

New Mean Sea Surface

AVISO Climate Change News - Sun, 2017-03-26 23:43
The key points of this CNES_CLS 2015 MSS are:
  • a drastic improvement of the shortest wavelengths,
  • a better correction of the oceanic variability,
  • more accuracy near the coast.
  • globally, strong reduction of errors when computing SLA
  • more homogeneity of accuracy compared to the former versions
This new version is based on a 20-year period (1993-2013) of altimetry data (mean profiles, geodetic mission and SLA): mean profiles from Topex/poseidon, ERS-2 , GFO, Jason-1, Jason-2, and Envisat; geodetic phase from ERS-1, Jason-1 and Cryosat-2. Further information:
  • Data: Auxiliary products: Mean Sea Surface
Categories: Climate Science News

Jason-3 integrated in the Mean Sea Level processing

AVISO Climate Change News - Fri, 2017-03-24 01:57
Almost three quarters of the Earth’s surface are covered by oceans: oceans are a key-element of our global climate system. It is a reality, the oceans respond to climate change: as a result of human activity and greenhouse gases, the climate is warming, the ocean expands and its level rises. Oceans are under close surveillance at all times: altimetry satellites accurately measure the sea level with a homogeneous and continuous global coverage since the launch of Topex-Poseidon in 1992. The Jason-3 mission complements this satellite constellation in flight by providing continuity of measurements that is essential for observing climate change. --> Use the interactive tool enabling to plot and download the Mean Sea Level trend times series and maps by selecting an area, a time-period (for time series only), one or several satellite missions. Further information:
  • Ocean indicators: Mean Sea Level, Processing and Corrections
  • Altimetry in videos for Jason-3 launch: Mean Sea Level
  • Applications: Mean Sea Level, Greenhouse effects
Categories: Climate Science News

12-19 March, 2017 week

AVISO Climate Change News - Thu, 2017-03-23 08:07
Réchauffement climatique : l'ONU tire la sonnette d'alarme (France Info, 2017/03/21)
Pérou : des inondations ont fait au moins 65 morts depuis janvier (France 24, 2017/03/18)
Changement climatique : les océans se réchauffent plus vite que prévu (Numerama, 2017/03/13)
Un glacier bolivien préservé en Antarctique (Tribune de Genève, 2017/03/12)
UNE ÉPONGE GÉANTE POUR NETTOYER L'OCÉAN APRÈS UNE FUITE DE PÉTROLE (Le Monde, 2017/03/11)
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Categories: Climate Science News

Arctic sea ice maximum at record low for third straight year

NSIDC Artic Sea Ice News - Wed, 2017-03-22 10:00

Arctic sea ice appears to have reached its annual maximum extent on March 7. This is the lowest maximum in the 38-year satellite record. NSIDC will post a detailed analysis of the 2016 to 2017 winter sea ice conditions in our regular monthly post in early April.

Overview of conditions Figure 1. Arctic sea ice extent for March 7, 2017 was 14.42 million square kilometers (5.57 million square miles). The orange line shows the 1981 to 2010 median extent for that day.

Figure 1. Arctic sea ice extent for March 7, 2017 was 14.42 million square kilometers (5.57 million square miles). The orange line shows the 1981 to 2010 median extent for that day. Sea Ice Index data. About the data

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

On March 7, 2017, Arctic sea ice likely reached its maximum extent for the year, at 14.42 million square kilometers (5.57 million square miles), the lowest in the 38-year satellite record. This year’s maximum extent is 1.22 million square kilometers (471,000 square miles) below the 1981 to 2010 average maximum of 15.64 million square kilometers (6.04 million square miles) and 97,000 square kilometers (37,000 square miles) below the previous lowest maximum that occurred on February 25, 2015. This year’s maximum is 100,000 square kilometers (39,000 square miles) below the 2016 maximum, which is now third lowest. (In 2016, we reported that year’s maximum as the lowest and 2015 the second lowest. An update to the Sea Ice Index last summer has changed our numbers slightly.)

Conditions in context Figure 2a. The graph above shows Arctic sea ice extent as of March 20, 2017, along with daily ice extent data for four previous years. 2016 to 2017 is shown in blue, 2015 to 2016 in green, 2014 to 2015 in orange, 2013 to 2014 in brown, and 2012 to 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.

Figure 2a. The graph above shows Arctic sea ice extent as of March 20, 2017, along with daily ice extent data for five previous years. 2016 to 2017 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

Figure 2b. The plot shows Arctic air temperature differences at the 925 hPa level in degrees Celsius from October 1, 2016 to February 28, 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.

Figure 2b. The plot shows Arctic air temperature differences at the 925 hPa level (about 2,500 feet above sea level) in degrees Celsius from October 1, 2016 to February 28, 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 Earth System Research Laboratory Physical Sciences Division
High-resolution image

It was a very warm autumn and winter. Air temperatures at the 925 hPa level (about 2,500 feet above sea level) over the five months spanning October 2016 through February 2017 were more than 2.5 degrees Celsius (4.5 degrees Fahrenheit) above average over the entire Arctic Ocean, and greater than 5 degrees Celsius (9 degrees Fahrenheit) above average over large parts of the northern Chukchi and Barents Seas. These overall warm conditions were punctuated by a series of extreme heat waves over the Arctic Ocean.

Data from the European Space Agency’s CryoSat-2 satellite indicate that this winter’s ice cover may be only slightly thinner than that observed at this time of year for the past four years. However, an ice-ocean model at the University of Washington (PIOMAS) that incorporates observed weather conditions suggests the volume of ice in the Arctic is unusually low.

The Antarctic minimum Figure 3. Antarctic sea ice extent for March 3, 2017 was 2.11 million square kilometers (813,000 million square miles). The orange line shows the 1981 to 2010 average extent for that day.

Figure 3. Antarctic sea ice extent for March 3, 2017 was 2.11 million square kilometers (815,000 square miles). The orange line shows the 1981 to 2010 median extent for that day. Sea Ice Index data. About the data

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

In the Southern Hemisphere, sea ice likely reached its minimum extent for the year on March 3, at 2.11 million square kilometers (815,000 square miles). This year’s minimum extent was the lowest in the satellite record, continuing a period of satellite-era record low daily extents that began in early November. However, the Antarctic system has been highly variable. As recently as 2015, Antarctic sea ice set record high daily extents, and in September 2014 reached a record high winter maximum.

The Antarctic minimum extent is 740,000 square kilometers (286,000 square miles) below the 1981 to 2010 average minimum of 2.85 million square kilometers (1.10 million square miles) and 184,000 square kilometers (71,000 square miles) below the previous lowest minimum that occurred on February 27, 1997.

Antarctic air temperatures during the autumn and winter were above average, but less so than in the Arctic. Air temperatures at the 925 hPa level (about 2,500 feet above sea level) near the sea ice edge have been about 1 to 2.5 degrees Celsius (2 to 4.5 degrees Fahrenheit) above the 1981 to 2010 average.

Final analysis pending

At the beginning of April, NSIDC scientists will release a full analysis of winter conditions, along with monthly data for March. For more information about the maximum extent and what it means, see the NSIDC Icelights post, the Arctic sea ice maximum.

Correction

On March 27, 2017, we made corrections to clarify the second paragraph under Conditions in context. The paragraph originally read:

Data from the European Space Agency’s CryoSat-2 satellite indicate that this winter’s ice cover is slightly thinner compared to the past four years. An ice-ocean model at the University of Washington that incorporates observed weather conditions suggests the volume of ice in the Arctic is unusually low for this time of year.

Categories: Climate Science News

[Jason-2] after the Safe Mode, nominal activities restart

AVISO Climate Change News - Wed, 2017-03-22 08:55
The PMA GPS OnBoard SoftWare has been uploaded successfully on Jason-2's spacecraft. Nominal recovery activities restart today (2017/03/22). The exact foreseen sequence for restart is now to switch on Poseidon, AMR and GPSP on Friday 24th around 10:30UTC (2017/03/24). This means that the first products should be available around 13:00UTC, after a first orbit of measurements. However, please note that those first products could be impacted by the drag make-up maneuver that needs to be performed around 13:00UTC. Christophe Marechal, JA2/3 CNES project manager, on behalf of Jason-2 project managers from NOAA, EUMETSAT and JPL Linked articles:
  • [Jason-2] Jason-2 in safe mode since March 15th, 19:19 UTC
Categories: Climate Science News

22 March, World Water Day: views from space

AVISO Climate Change News - Wed, 2017-03-22 00:21
Fresh water, essential for all life on Earth, is present in a finite amount on our planet (only 0.007% of all the planet's water is accessible for human consumption via rivers, streams, reservoirs and lakes).

In particular, it is essential for human activities. The consumption of fresh water is growing three times faster than the population. But global water resources are shared unequally between countries and continents: Asia accounts for 60% of the world’s population but has only 36% of its water, while South America has only 7% of the population but 30% of the water.

Today, water is no longer simply a problem for "poor countries": drought is increasingly afflicting areas of China, the USA, Australia and Europe. Aquifers are drying up and pollution and salinity are reducing water reserves even further. It has become essential to introduce tools to optimise the management of these resources.

At the moment, hydrology is essentially based on probes and gauging stations installed in situ at the edges of watercourses or lakes. But these instruments are distributed very unevenly across the surface of the globe, and it is often difficult to keep them properly maintained and calibrated. Satellite-based observation helps ensure the regularity and homogeneity of measurements from all over the planet. Satellite missions have led to major advances in environmental studies, including in the management of water resources. Among other achievements, nadir altimetry can acquire the height of the water of certain lakes or rivers, and the wide-swath altimetry made possible by SWOT will soon extend this possibility to include all inland waters.

Precipitation, evaporation and evapotranspiration, water levels and surface areas, the extent of frozen regions, soil moisture, groundwater reserves, water quality, surface water temperature, depth, mapping of watersheds – all this information can be and already is being provided today by Earth observation satellites. In addition, by combining all these sources, combining some of them with in situ measurements and/or with models, synoptic maps can be compiled on the situation of a watershed, a water deficit for example, risk maps, estimates of the flow of rivers, snowmelt, or the speed of the flow and shrinkage of glaciers.

The use of satellite observation in hydrology is bound to be called on increasingly, with ever more uses combining all available measurements and data, for better management of this most vital of resources: fresh water.

Categories: Climate Science News

5-12 March, 2017 week

AVISO Climate Change News - Thu, 2017-03-16 07:12
Réchauffement climatique: la Grande Barrière de corail en Australie connaît un deuxième épisode de blanchiment  (Arc Info, 2017/03/10)
Le réchauffement climatique affectera les 4/5 des océans du monde d'ici 2050 (News environnement, 2017/03/08)
Sciences : un réchauffement climatique en dessous de 1,5°C, seul moyen de sauver la banquise... et la planète ? (Sud Ouest, 2017/03/08)
Le changement climatique dérange les océans (Le Figaro, 2017/03/07)
Des fluctuations climatiques très semblables d'un bout à l'autre de la chaine alpine et la fonte des glaciers s'était fortement accélérée (Média Terre, 2017/03/07)
L'Arctique est-il en train de mourir (et nous avec) (France TV Info, 2017/03/05)
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Categories: Climate Science News

[Jason-2] Jason-2 in safe mode since March 15th, 19:19 UTC

AVISO Climate Change News - Thu, 2017-03-16 06:11
The satellite is currently in a safe and stable Sun-pointing configuration. Expert teams from CNES and industry (TAS) have been activated and detailed investigations will start today. First investigations performed this night show that Gyrometer 1 was blocked, causing the reconfiguration to SHM. All other equipments were OK at the time of the reconfiguration. I will probably be able to get back by COB with news on the health of Gyro 1. The four partners operational teams are working closely to support current and future operations. The mission will resume as soon as possible, and we will keep you informed of our progress. Christophe Marechal, CNES Jason 2 project manager on behalf of Jason-2 project managers from NOAA, EUMETSAT and JPL.
Categories: Climate Science News

February 26 - March 5, 2017 week

AVISO Climate Change News - Thu, 2017-03-09 09:03
L'Arctique est-il en train de mourir (et nous avec) ? (France TV info, 2017/03/05)
Un iceberg géant va faire monter le niveau des mers (Ouest France, 2017/03/03)
De plus en plus inquiétant: si ça continue comme ça, il n'y aura plus un seul ours polaire d'ici 2100 (Newsmonkey, 2017/02/27)
La météo bizarre est-elle due au réchauffement climatique ? (Meteo Media, 2017/02/26)
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Categories: Climate Science News

Another warm month in the Arctic

NSIDC Artic Sea Ice News - Mon, 2017-03-06 10:00

High air temperatures observed over the Barents and Kara Seas for much of this past winter moderated in February. Overall, the Arctic remained warmer than average and sea ice extent remained at record low levels.

Overview of conditions  National Snow and Ice Data Center|High-resolution image

Figure 1. Arctic sea ice extent for February 2017 was 14.28 million square kilometers (5.51 million square miles). The magenta line shows the 1981 to 2010 median extent for the month. Sea Ice Index data. About the data

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

Arctic sea ice extent for February 2017 averaged 14.28 million square kilometers (5.51 million square miles), the lowest February extent in the 38-year satellite record. This is 40,000 square kilometers (15,400 square miles) below February 2016, the previous lowest extent for the month, and 1.18 million square kilometers (455,600 square miles) below the February 1981 to 2010 long term average.

Ice extent increased at varying rates, with faster growth during the first and third weeks, and slower growth during the second and fourth weeks. Most of the ice growth in February occurred in the Bering Sea, though extent in the Bering remained below average by the end of the month. Sea ice extent in the Sea of Okhotsk substantially decreased mid-month before rebounding to almost typical levels at the end of the month. Overall, however, the ice retreated in this region. Extent in the Barents and Kara Seas remained low through the month as is has all season, with little change in the ice edge location.

Conditions in context  National Snow and Ice Data Center|High-resolution image

Figure 2a. The graph above shows Arctic sea ice extent as of March 5, 2017, along with daily ice extent data for four previous years. 2016 to 2017 is shown in blue, 2015 to 2016 in green, 2014 to 2015 in orange, 2013 to 2014 in brown, and 2012 to 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. About the data

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

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

Figure 2b. The plot shows Arctic air temperature differences at the 925 hPa level in degrees Celsius for February 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 Earth System Research Laboratory Physical Sciences Division
High-resolution image

Air temperatures at the 925 hPa level (approximately 2,500 feet above sea level) remained 2 to 5 degrees Celsius (4 to 9 degrees Fahrenheit) above average over the Arctic Ocean. The high air temperatures observed over the Barents and Kara Seas for much of this past winter moderated in February. February air temperatures over the Barents Sea ranged between 4 to 5 degrees Celsius (8 to 9 degrees Fahrenheit) above average, compared to 7 degrees Celsius (13 degrees Fahrenheit) above average in January. Recall that these January temperature extremes were associated with a series of strong cyclones entering the Arctic Ocean from the North Atlantic, drawing in warm air. Sea level pressure in February was nevertheless lower than average over much of the Arctic Ocean. Sea level pressure was higher than average over the Bering Sea and just north of Scandinavia.

February 2017 compared to previous years  National Snow and Ice Data Center| High-resolution image

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

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

The linear rate of decline for February is 46,900 square kilometers (18,100 square miles) per year, or 3 percent per decade.

Antarctic minimum extent  National Snow and Ice Data Center|High-resolution image

Figure 4a. The graph above shows Antarctic sea ice extent as of March 5, 2017, along with daily ice extent data for four previous years. 2016 to 2017 is shown in blue, 2015 to 2016 in green, 2014 to 2015 in orange, 2013 to 2014 in brown, and 2012 to 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

 National Snow and Ice Data Center|High-resolution image

Figure 4b. This graph shows monthly ice extent for February, plotted as a time series of percent differences from the 1981 to 2010 average. The dotted gray line shows the linear trend. Sea Ice Index data. About the data

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

Antarctic sea ice is nearing its annual minimum extent and continues to track at record low levels for this time of year. On February 13, Antarctic sea ice extent dropped to 2.29 million square kilometers (884,000 square miles), setting a record lowest extent in the satellite era. The previous lowest extent occurred on February 27, 1997. By the end of February, extent had dropped even further to 2.13 million square kilometers (822,400 square miles). The record lows are not surprising, given Antarctic sea ice extent’s high variability. Just a few years back, extent in the region set record highs (Figure 4b).

Sea ice extent was particularly low in the Amundsen Sea, which remained nearly ice-free throughout February. Typically, sea ice in February extends at least a couple hundred kilometers along the entire coastline of the Amundsen. Near-average ice extent persisted in the Weddell Sea and in several sectors along the East Antarctic coast.

Continuity of the sea ice record  Walt Meier, NASA| High-resolution image

Figure 5. This chart shows the lifespans of current and expected future orbiting passive microwave sensors.

Credit: W. Meier, NASA Goddard Space Flight Center Cryospheric Sciences Laboratory
High-resolution image

As noted last year, the sensor that NSIDC had been using for sea ice extent, the Special Sensor Microwave Imager and Sounder (SSMIS) on the Defense Meteorological Satellite Program (DMSP) F17 satellite, started to malfunction. In response, NSIDC switched to the SSMIS on the newer F18 satellite. Later, F17 recovered to normal function, though it recently started to malfunction again.

The DMSP series of sensors have been a stalwart of the sea ice extent time series, providing a continuous record since 1987. Connecting this to data from the earlier Scanning Multichannel Microwave Radiometer (SMMR) results in a continuous record starting in 1979 of high quality and consistency. However, with the issues of F17 and last year’s loss of the newest sensor, F19, grave concerns have arisen about the long-term continuity of the passive microwave sea ice record. Only two DMSP sensors are currently fully capable for sea ice observations: F18 and the older F16; these two sensors have been operating for over 7 and 13 years respectively, well beyond their nominal 5-year lifetimes.

The only other similar sensor currently operating is the Japan Aerospace Exploration Agency (JAXA) Advanced Microwave Scanning Radiometer 2 (AMSR2), which is approaching its 5-year design lifetime in May 2017. NSIDC is now evaluating AMSR2 data for integration into the sea ice data record if needed. Future satellite missions with passive microwave sensors are either planned or proposed by the U.S., JAXA, and ESA, but it is unlikely that a successor to the DMSP series and AMSR2 will be operational before 2022. This presents a growing risk of a gap in the sea ice extent record. Should such a gap occur, NSIDC and NASA would seek to fill the gap as much as possible with other types of sensors (e.g., visible or infrared sensors).

Categories: Climate Science News

Temporary unavailability of the CNES ftp server on March 8-9, 2017

AVISO Climate Change News - Mon, 2017-03-06 03:20
For maintenance reason, the Cnes ftp server (ftp://avisoftp.cnes.fr/AVISO/pub) is unavailable on
  • March 8, 2017 between 7:00 and 9:00 UTC,
  • March 9, 2017 between 7:00 and 9:00 UTC.
We apologize for the inconvenience.
Categories: Climate Science News

March 2017: Satellites see the highs and lows of the biggest lake in China

AVISO Climate Change News - Wed, 2017-03-01 04:06
To celebrate the World Water Day (March 22nd), a satellite-based focus on the biggest lake in...
Categories: Climate Science News

20-26 February 2017 week

AVISO Climate Change News - Wed, 2017-03-01 03:29
50 récifs de corail testés pour lutter contre le changement climatique (News Environnement, 2017/02/15)
La Méditerranée, terre fertile pour le réchauffement (Natura Sciences, 2017/02/23)
Pourquoi les océans sont essentiels dans la régulation du climat mondial (Huffpostmaghreb, 2017/02/22)
Les océans pollués par des particules invisibles de plastique (Le Monde, 2017/02/22)
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Categories: Climate Science News

12-19 February, 2017 week

AVISO Climate Change News - Thu, 2017-02-23 01:52
Les glaciers alpins fondent à très grande vitesse (Le Monde, 2017/02/16)
Sentinels Warn of Dangerous Ice Crack (ESA, 2017/02/16)
Des fluctuations climatiques très semblables d’un bout à l’autre de la chaine alpine et une fonte des glaciers qui s’accélère depuis 2003 (CNRS, 2017/02/15)
Atlantique Nord : le risque d'un refroidissement rapide au XXIe siècle revu à la hausse (CNRS, 2017/02/15)
Pacific Wind and Current Changes Bring Warm, Wild Weather (Earth Observatory, 2017/02/14)
La pollution chimique gagne les abysses (Le Monde, 2017/02/13)
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Categories: Climate Science News

5-12 February, 2017 week

AVISO Climate Change News - Thu, 2017-02-16 08:37
Climat : les mangroves s'avèrent de loin l'écosystème qui stocke le plus de carbone (Science et Vie, 2017/02/10)
Les manchots du Cap menacés par la surpêche et le réchauffement climatique (Sciences et Avenir, 201/02/10)
Comprendre le comportement des forêts tropicales dans le cadre du système climatique changeant de la Terre (MédiaTerre, 2017/02/03)
Climate change could trigger strong sea level rise (Space Daily, 2017/01)
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Categories: Climate Science News

22 January - 5 February, 2017 weeks

AVISO Climate Change News - Thu, 2017-02-09 03:23
Tara. Des récifs coralliens en danger (Telegramme, 2017/02/05)
El Niño n'explique pas tout (Pour la Science, 2017/02)
Oceanographic analysis offers potential crash site of MH370 (Terradaily, 2017/01/24)
Une animation de la NASA montre l'ampleur du réchauffement climatique (Le Monde, 2017/01/23)
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Categories: Climate Science News

2017 ushers in record low extent

NSIDC Artic Sea Ice News - Tue, 2017-02-07 12:18

Record low daily Arctic ice extents continued through most of January 2017, a pattern that started last October. Extent during late January remained low in the Kara, Barents and Bering Seas. Southern Hemisphere extent also tracked at record low levels for January; globally, sea ice cover remains at record low levels.

Overview of conditions extent map

Figure 1. Arctic sea ice extent for January 2017 was 13.38 million square kilometers (5.17 million square miles). The magenta line shows the 1981 to 2010 median 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 January 2017 averaged 13.38 million square kilometers (5.17 million square miles), the lowest January extent in the 38-year satellite record. This is 260,000 square kilometers (100,000 square miles) below January 2016, the previous lowest January extent, and 1.26 million square kilometers (487,000 square miles) below the January 1981 to 2010 long-term average.

Ice growth stalled during the second week of the month, and the ice edge retreated within the Kara and Barents Seas, and within the Sea of Okhotsk. After January 16, extent increased at a more rapid pace, but the rate of ice growth was still below average for January as a whole. For a few days towards the end of the month, the extent was slightly greater than recorded in 2006, a year which also saw many record low days in January, but by the 30th it was tracking below 2006. Through most of January the ice edge remained north of the Svalbard Archipelago, largely due to the inflow of warm Atlantic water along the western part of the archipelago. However, by the end of January, some ice was found to the northeast and northwest of Svalbard. At the end of January, ice extent remained well below average within the Kara, Barents, and Bering Seas.

Conditions in context time series graph

Figure 2a. The graph above shows Arctic sea ice extent as of February 5, 2017, along with daily ice extent data for four previous years. 2016 to 2017 is shown in blue, 2015 to 2016 in green, 2014 to 2015 in orange, 2013 to 2014 in brown, and 2012 to 2013 in purple. The 1981 to 2010 average 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. The plot shows Arctic air temperature difference from average, in degrees Celsius, for January 2017.

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

January air temperatures at the 925 hPa level (approximately 2,500 feet above sea level) were above average over nearly all of the Arctic Ocean, continuing the pattern that started last autumn (Figure 2b). Air temperatures were more than 5 degrees Celsius (9 degrees Fahrenheit) above the 1981 to 2010 average over the northern Barents Sea and as much as 4 degrees Celsius (7 degrees Fahrenheit) above average in the northern Chukchi and East Siberian Seas. It was also unusually warm over northwestern Canada. Cooler than average conditions (up to 3 degrees Celsius, or 5 degrees Fahrenheit below average) prevailed over the northwest part of Russia and the northeast coast of Greenland.

Atmospheric circulation over the Arctic during the first three weeks of January was characterized by a broad area of below average sea level pressure extending over almost the entire Arctic Ocean. Higher-than-average sea level pressure dominated over the Gulf of Alaska and the North Atlantic Ocean south of Iceland. This set up warm southerly winds from both the northern North Atlantic and the Bering Strait areas, helping to explain the high January air temperatures over the Arctic Ocean. According to the analysis of NASA scientist Richard Cullather, the winter of 2015 to 2016 was the warmest ever recorded in the Arctic in the satellite data record. Whether the winter of 2016 to 2017 will end up warmer remains to be seen; conditions are typically highly variable. For example, during the last week of January, the area of low pressure shifted towards the Siberian side of the Arctic. In the northern Laptev Sea, pressures fell to more than 20 hPa below the 1981 to 2010 average. This was associated with a shift towards cooler conditions over the Arctic Ocean, which may explain why ice extent towards the end of the month rose above levels recorded in 2006.

January 2017 compared to previous years trend graph

Figure 3. Monthly January ice extent for 1979 to 2017 shows a decline of 3.2 percent per decade.

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

Through 2017, the linear rate of decline for January is 47,400 square kilometers (18,300 square miles) per year, or 3.2 percent per decade.

Amundsen Sea nearly free of ice S_daily_extent_hires

Figure 4. Antarctic sea ice extent for February 5, 2017 shows the Amundsen Sea nearly free of ice. The orange line shows the 1981 to 2010 median extent for that day. Sea Ice Index data. About the data

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

Extent is tracking at records low levels in the Southern Hemisphere, where it is currently summer. As shown in this plot for February 5, this is primarily due to low ice extent within the Amundsen Sea, where only a few scattered patches of ice remain. By contrast, extent in the Weddell Sea is now only slightly below average. This pattern is consistent with persistent above average air temperatures off western Antarctica.

Further reading

Cullather, R. I., Y.-K. Lim, L. N. Boisvert, L. Brucker, J. N. Lee, and S. M. J. Nowicki. 2016. Analysis of the warmest Arctic winter, 2015-2016. Geophysical Research Letters,43, doi:10.1002/2016GL071228.

Categories: Climate Science News

Feb. 2017: Tidal currents make a buoy's path spiral

AVISO Climate Change News - Tue, 2017-02-07 02:55
Altimetry helped to improve the tide models, including tidal currents. A, Argonautica buoy path can...
Categories: Climate Science News
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