Climate Science News

Autumn freeze-up amps up

NSIDC Artic Sea Ice News - Tue, 2018-12-04 13:05

The Arctic freeze-up season is well underway, with ice extent increasing faster than average for most regions in November. Exceptions were in the Chukchi and Barents Seas, where the ice has been slow to form. November snow cover over North America was the most extensive since 1966.

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

Figure 1. Arctic sea ice extent for November 2018 was 9.80 million square kilometers (3.78 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 November averaged 9.80 million square kilometers (3.78 million square miles). This was the ninth lowest November in the 1979 to 2018 satellite record, falling 900,000 square kilometers (347,000 square miles) below the 1981 to 2010 average, yet 1.14 million square kilometers (440,000 square miles) above the record November low in 2016.

Sea ice extent increased quite rapidly during the early part of the month, bringing the extent within the interdecile range of the 1981 to 2010 climatology during the latter half of the month. This was due in part to the Laptev Sea finally freezing up after having extensive open water through the end of October, as discussed in our previous post. There was also considerable ice growth in Hudson Bay, Baffin Bay, the Chukchi Sea, and the Kara Sea. This rapid growth is not particularly surprising. As the sun has set in the Arctic, the atmosphere has strongly cooled. As soon as the remaining open ocean water loses its heat to the atmosphere, ice growth occurs. Further, the increased area of open water in summer had led to increased frequency of rapid ice growth events in mid to late autumn, in which more than 1 million square kilometers (386,000 square miles) of ice can form within a 7-day period (see Stroeve and Notz, 2018).

Despite relatively fast ice growth during November, at the end of the month substantial open water still remained in the Chukchi and Barents Seas. The Chukchi Sea was in general completely ice covered by the end of November in the 1980s through to the early 2000s. However, low ice extent in the Chukchi Sea into late autumn has become quite common in recent years and this year’s extent is comparable to the new normal for this time of year in the region. Similarly, in the Barents Sea, low autumn extent has become common in recent years as warm Atlantic water is preventing ice growth farther north—a process called “Atlantification.”

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

Figure 2. The graph above shows Arctic sea ice extent as of December 03, 2018, along with daily ice extent data for four previous years and the record low year. 2018 is shown in blue, 2017 in green, 2016 in orange, 2015 in brown, 2014 in purple, and 2012 in dotted 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

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

Figure 2b. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for November 2018. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

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

Air temperatures at the 925 mb level (about 2,500 feet above the surface) were modestly above average in November across most of the Arctic Ocean (up 2 degrees Celsius or 4 degrees Fahrenheit), the main exception being slightly cooler than average conditions in the Laptev Sea (Figure 2b). Average low sea level pressure centered over the Siberian coast of the Kara Sea, a pattern tending to draw in cold continental air from Siberia over the Laptev Sea. By contrast, temperatures were up to 4 degrees Celsius (7 degrees Fahrenheit) above average over the East Greenland Sea and extending east over Scandinavia. It was also quite warm, up to 6 degrees Celsius (11 degrees Fahrenheit), over the interior of Alaska

November 2018 compared to previous years  National Snow and Ice Data Center| High-resolution image

Figure 3. Monthly November ice extent for 1978 to 2018 shows a decline of 5.o percent per decade.

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

Overall, sea ice extent during November 2018 increased 3.08 million square kilometers (1.19 million square miles). This is 994,000 square kilometers (384,000 square miles) greater than the 1981 to 2010 average November extent increase. The linear rate of sea ice decline for November is 53,500 square kilometers (21,000 square miles) per year, or 5.0 percent per decade relative to the 1981 to 2010 average.

The “Atlantification” of the Barents Sea  A. Barrett, National Snow and Ice Data Center

Figure 4. This figure shows departures from average sea ice extent in the Barents Sea sector of the Arctic Ocean by year and month. Above average extent is shown by red and orange colors, while below average extent is shown in blue colors.

Credit: A. Barrett, National Snow and Ice Data Center
High-resolution image

 Barton et al., 2018, Journal of Physical Oceanography

Figure 4b. This graph shows average Sea Surface Temperature (SST) across the Barents Sea with a 12-month running mean (blue line). The linear trend for the periods 1985 to 2004 and December 2004 to 2016 are shown (green lines). Credit: Barton et al., 2018, Journal of Physical Oceanography
High-resolution image

As noted above, the Barents Sea continues to be largely ice free. This is part of a broader pattern emerging over the last decade of greatly reduced ice extent in this area in all seasons, especially from autumn through spring (Figure 4). These reductions in ice extent appear to be heavily influenced by the inflow of Atlantic water into the region. While increased temperatures and inflow of Atlantic water have been observed over the last two decades, this warm and salty water usually lies below the colder, less dense Arctic surface waters. This largely keeps the ocean heat from influencing the sea cover. New research by Benjamin Barton and colleagues (Barton et al., 2018) suggests that the sea surface temperatures in the Barents Sea have increased in recent years (Figure 4b) as this warm Atlantic water has started to mix with the surface. A key factor driving this mixing appears to be the decline in sea ice itself and corresponding less freshwater at the surface when that ice melts in summer. This leads to a weaker ocean density stratification, making it easier to mix warm, salty Atlantic waters upwards. This can be viewed as a feedback mechanism—less ice means less summer melt and a weaker ocean stratification, helping to mix the Atlantic heat upwards, which in turn means less ice. Scientists have referred to this change as “Atlantification” of the Barents Sea. The warm water from the Atlantic prevents ice formation and is the main reason why the winter ice edge in the Barents is farther north than in other parts of the Arctic.

An early start to the snow season for much of North America Figure 5.

Figure 5. This graph shows snow cover extent anomalies in the Northern Hemisphere for November from 1966 to 2018. The anomaly, or departure from average, is relative to the 1981 to 2010 average.

Credit: National Snow and Ice Data Center, courtesy Rutgers University Global Snow Lab
High-resolution image

As many US travelers noticed over the Thanksgiving weekend, the snow season has arrived early over parts of North America. While parts of Alaska had their latest first snowfall, based on data at the Rutgers Global Snow Lab, North America as a whole had the highest November snow extent in the 1966 to 2018 record (Figure 5). Above average snow cover was particularly notable over central and eastern Canada. Over Eurasia, snow cover was slightly above average for this time of year. The extensive snow cover over eastern Canada was related to low pressure over the North Atlantic that brought cold air from the Arctic into the region.

Antarctic note

Antarctic sea ice extent declined much more slowly than average in November, but large areas in the northern Weddell Sea and the ocean north of Dronning Maud Land have open, low-concentration pack ice. Several polynyas have appeared near the Antarctic coast, in the Ross Sea, Thwaites Glacier region, Prydz Bay west of the Amery Ice Shelf, and in the Weddell Sea. The Weddell Sea polynyas are completely offshore near the region of the Maud Rise bathymetric feature, and may be an indication of a return of the Maud Rise Polynya feature (see 2016 to 2017 ASINA posts). Higher-than-average temperatures prevailed in the Ross Sea and Weddell Sea, up 1 to 3 degrees Celsius (2 to 5 degrees Fahrenheit) from the 1981 to 2010 average. Meanwhile, cool conditions were present near Thwaites Glacier and the Amery Ice Shelf region, with temperatures 1.5 degrees Celsius (3 degrees Fahrenheit) below average.

Reference

Barton, B. I., Y. Lenn, and C. Lique. 2018. Observed Atlantification of the Barents Sea causes the polar front to limit the expansion of winter sea ice. Journal of Physical Oceanography, 48, 1849–1866, doi:10.1175/JPO-D-18-0003.1.

Stroeve, J. C. and D. Notz. 2018. Changing state of Arctic sea ice across all seasons. Environmental Research Letters. doi:10.1088/1748-9326/aade56.

Categories: Climate Science News

December 2018: Retrieving hidden water contribution to river from space

AVISO Climate Change News - Mon, 2018-12-03 01:53
The minimum flow a river can have can be estimated using the overall discharge. This is one of Swot...
Categories: Climate Science News

12 - 24 November 2018 weeks

AVISO Climate Change News - Tue, 2018-11-27 09:43
How the Antarctic Circumpolar Current Helps Keep Antarctica Frozen (The Marine Executive, 24/11/2018) Beneath Antarctica’s Ice Is a Graveyard of Dead Continents (The New York Times, 23/11/2018) What a sinking island can tell us about sea-level change and earthquakes (Phys.org, 21/11/2018) How rare are November hurricanes? (EarthSky, 20/11/2018) The Earth Is Eating Its Own Oceans (Live science, 14/11/2018) Why Is the Gulf of Maine Warming Faster Than 99% of the Ocean? (EOS, 12/11/2018) Le réchauffement climatique menace l'humanité de... 467 façons ! (Sciences et Avenir, 22/11/2018) Les niveaux de gaz à effet de serre atteignent un nouveau record dans l'atmosphère (France Info, 22/11/2018) Un cachalot retrouvé mort avec 6 kg de plastique dans le ventre en Indonésie (Ouest France, 21/11/2018) Deux projets fous contre la montée des eaux (Science & Vie, 21/11/2018) Afrique : au Sahel, pas de retour à la normale après la "grande sécheresse" (L'Obs, 13/11/2018) Climat : à quoi servent les COP ? (Geo, 12/11/2018) 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

29 October - 12 November 2018 weeks

AVISO Climate Change News - Mon, 2018-11-12 08:32
Hurricane Season Is Almost Over - So Why Are Meteorologists Watching The Caribbean? (Forbes, 11/11/2018) NASA IceBridge Flight Spots Massive Antarctic Iceberg B-46 (SciTechDaily, 11/11/2018) Still waiting on El Niño for winter 2018 (Surfline, 10/11/2018) An ice age lasting 115,000 years in two minutes (Phys.org, 06/11/2018) GRACE-FO resumes data collection (Space Daily, 05/11/2018) Deep Floats Reveal Complex Ocean Circulation Patterns (EOS, 05/11/2018) Sea level rise forcing Bangladeshis to migrate (SciDevNet, 30/10/2018) How the Greenland ice sheet fared in 2018 (Phys.org, 29/10/2018) La subida del nivel del mar se está acelerando (Tiempo.com, 12/11/2018) Réchauffement climatique dans les Pyrénées : +1,2 degré en 50 ans ! Alerte rouge pour le massif (, 12/11/2018) Des images satellite révèlent des vestiges anciens sous les glaces antarctiques (Sputnik, 10/11/2018) Une île a mystérieusement disparu au Japon (Paris Match, 02/11/2018) Méditerranée : la quasi-totalité des sites Unesco menacés par le réchauffement climatique (Futura Sciences, 29/10/2018) 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

CFOSAT: first results

AVISO Climate Change News - Fri, 2018-11-09 09:56
The French-Chinese satellite CFOSAT was successfully launched on October 29th (see our dedicated news). On November 1st, the French SWIM instrument has been switched on, its rotating antenna system has been released and activated. The SWIM status is nominal with great results for the first products evidencing SWIM perfect behaviour.  The CNES processing chain in near-real time is enable to generate product levels-1 & 2. A comparison between the Significant Wave Height from SWIM instrument and ECMWF forecast shows good fitting on oceanic structures.

 

The commissioning phase is starting with these promising results. In the coming weeks, calibration works will be perform at instrument level, before the data are made available for scientific experts during the Calibration/Validation phase.

On the Chinese side, the rotating fan beam scatterometer SCAT dedicated to the ocean surface wind measurements is also operational and works properly.

Further information:
  • Missions: CFOSAT
  • CNES presentation : SWIM first days results in science modes - 03/11/2018
Categories: Climate Science News

Unusual warmth continues

NSIDC Artic Sea Ice News - Tue, 2018-11-06 08:30

Over the Pacific side of the Arctic, a pattern of unusual warmth noted in last month’s post continued. While sea ice extent in the Chukchi and Beaufort Seas remains below average, extent remains especially low on the Atlantic side of the Arctic in the Barents and Laptev Seas. October sea ice extent in the Arctic was the third lowest in the satellite record.

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

Figure 1. Arctic sea ice extent for October, 2018 was 6.06 million square kilometers (2.34 million square miles). The orange line shows the 1981 to 2010 average extent for that day. Sea Ice Index data. About the data

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

Figure 1b. This maps shows the difference between sea ice extent on October 1 and October 31, 2018.

Figure 1b. This maps shows the difference between sea ice extent on October 1 and October 31, 2018.

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

Arctic sea ice extent for October 2018 averaged 6.06 million square kilometers (2.34 million square miles), the third lowest October extent in the 1979 to 2018 satellite record. This was 2.29 million square kilometers (884,000 square miles) below the 1981 to 2010 average, and 170,000 square kilometers (66,000 square miles) above the record low recorded for October 2012.

Sea ice gain during the first half of the month was quite slow. By the third week of October, extent was still tracking below all years except 2016. However, toward the end of the month, the pace of ice growth increased.

Ice growth through the month was strong in the Beaufort and Chukchi Seas, but extent remained below average in these areas at the end of the month. A large area of open water remained in the Laptev Sea, which is unprecedented in the satellite record at the end of October. Especially prominent was the lack of ice growth on the Atlantic side of the Arctic in the Barents Sea, and in some regions, a slight contraction of the ice edge further north (Figure 1b). As a result, extent is presently far below average in this area, and is the primary reason why October extent for the Arctic as a whole is third lowest on record.

Conditions in context

Figure 2a. The graph above shows Arctic sea ice extent as of November 5, 2018, along with daily ice extent data for four previous years and 2012, the record low year. 2018 is shown in blue, 2017 in green, 2016 in orange, 2015 in brown, 2014 in purple, and 2012 in dotted 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 2. This plot shows departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for June 2018. Yellows and reds indicate higher than average temperature; blues and purples indicate lower than average temperature.

Figure 2b. This plot shows departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for October 2018. Yellows and reds indicate higher than average temperature; blues and purples indicate lower than average temperature.

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

October air temperatures at the 925 hPa level (about 2,500 feet above the surface) were above average across nearly all of the Arctic Ocean, but especially high temperatures—5 to 7 degrees Celsius (9 to 13 degrees Fahrenheit) above average—were found over the Beaufort and Chukchi Seas and extending poleward. The most extreme warmth was located over central Alaska, where temperatures were up to 7 degrees Celsius (13 degrees Fahrenheit) higher than average (Figure 2b).

A high-pressure ridge at 500 hPa over Alaska persisted through the month, extending onto the Chukchi and Beaufort Seas. This temperature pattern is broadly similar to that recorded for September. Below average sea ice extent over the Beaufort and Chukchi Seas is consistent with this unusual warmth. While the temperature pattern appears to be largely driven by the atmospheric circulation pattern, heat loss from the upper ocean to the lower atmosphere during ice formation likely contributed.

Why extent remains so low in the Barents Sea is not immediately clear from patterns of atmospheric circulation and temperature. October air temperatures at the 925 hPa level were only 1 to 3 degrees Celsius (2 to 5 degrees Fahrenheit) above average, associated with a trough of low pressure at sea level extending from Iceland into the region. While further investigation is warranted, this lack of ice growth may relate to the observed “Atlantification” of the Barents Sea, in which the cold, low density surface layer of the Arctic Ocean has weakened, allowing the heat from the warm Atlantic waters to more readily inhibit ice formation. It will be instructive to monitor ice growth rates in this area through the coming winter.

October 2018 compared to previous years Figure 3. Monthly October ice extent for 1979 to 2018 shows a decline of 9.5 percent per decade.

Figure 3. Monthly October ice extent for 1979 to 2018 shows a decline of 9.5 percent per decade.

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

Sea ice extent for October 2018 fell below the long-term linear trend line. The linear rate of sea ice decline for October is 79,000 square kilometers (31,000 square miles) per year, or 9.5 percent per decade relative to the 1981 to 2010 average.

Laptev lacking ice

Figure 4. This graph shows sea ice extent in the Laptev Sea from September 1 to October 31. The black line depicts the 1979 to 2017 median; the light grey lines represent the minimum and maximum sea ice extents; and the blue line shows the 2018 sea ice extent.

Credit: W. Meier, NSIDC
High-resolution image

Another notable feature in the Arctic ice pack at the end of October was the significant amount of open water in the Laptev Sea. Even in 2007 and 2012, the previous record low minimum extent years, the Laptev had nearly completely frozen over by the end of October. As late as October 29, the Laptev sea ice extent was less than 500,000 square kilometers (193,000 square miles). The 1981 to 2010 average extent on that date is 870,000 square kilometers (336,000 square miles)—essentially the entirety of the defined Laptev Sea region. By mid-October, the long-term average sea ice extent exceeds 800,000 square kilometers (309,000 square miles). This year, the mid-October sea ice extent within the Laptev Sea was barely above 100,000 square kilometers (39,000 square miles), about 13 percent of average.

The cause of this lack of ice is multifaceted. Ocean heat gained during the summer is likely delaying freeze-up. As noted above, air temperatures were above average over the region. This may in part be a result of the ocean heat, though low pressure centered over the Barents and Kara Seas also brought in warm air and winds from the south, keeping the ice edge from advancing.

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

Figure 5. This plot shows the departure from average air temperature in Antarctica at the 925 hPa level, in degrees Celsius, for October 2018. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

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

As noted in the previous post, Antarctica’s annual maximum sea ice extent of 18.15 million square kilometers (7.01 million square miles) was reached on October 2, the fourth lowest maximum in the satellite record.

Antarctic sea ice extent for October 2018 averaged 17.66 million square kilometers (6.82 million square miles), also the fourth lowest in the satellite record. Sea ice extent was particularly low in the sector south of Australia, south of Africa, and in the Bellingshausen and Amundsen Seas. Locations and sizes of these regional features varied through the course of the month as storms and strong winds shifted. Air temperatures at 925 hPa were 3 to 6 degrees Celsius (5 to 11 degrees Fahrenheit) above the 1981 to 2010 average in West Antarctica and the southern Antarctic Peninsula, and 2 to 3 degrees Celsius (4 to 5 degrees Fahrenheit) above average over a wide part of the Bellingshausen and Amundsen Seas. However, temperatures in the Weddell Sea region were 2 to 6 degrees (4 to 11 degrees Fahrenheit) below average.

Categories: Climate Science News

November 2018: Simulating the North Atlantic ocean turbulence at a kilometer-scale

AVISO Climate Change News - Wed, 2018-10-31 11:00
To achieve a better understanding of submesoscale turbulence contribution in global ocean...
Categories: Climate Science News

CFOSAT: successful launch

AVISO Climate Change News - Mon, 2018-10-29 08:25

Click on the image above to access to the video of the CFOSAT launch. Credits CNSA.

Further information
  • CFOSAT: Missions
  • CNES website: France-China space cooperation - CFOSAT in orbit
Categories: Climate Science News

15 - 29 October 2018 weeks

AVISO Climate Change News - Mon, 2018-10-29 03:40
France-China space cooperation - CFOSat in orbit (CNES, 29/10/2018) Long March 2C lofts CFOSAT for CNES (Nasa spaceflight, 28/10/2018) El Nino alert gives first indications for Christmas weather (News.com, 25/10/2018) Polar Researchers Spot Two Rectangular Icebergs (Universe Today, 24/10/2018) State of the climate: New record ocean heat content and a growing El Niño (Carbon Brief, 23/10/2018) Mad scientists flip the Earth’s spin in climate models, watch water go nuts (Ars Technica, 17/10/2018) Climat : lancement "historique" ce lundi matin d'un satellite franco-chinois (Midi Libre, 29/10/2018) Les micro-algues, ce côté toxique du poumon de la planète (Sciences et Avenir, 25/10/2018) Méditerranée : 5 actions clé pour sauver notre mer (Futura Sciences, 24/10/2018) Réchauffement: et si le climat basculait? (L'Express, 21/10/2018) 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

Data delivery on the CNES FTP Server delayed

AVISO Climate Change News - Fri, 2018-10-26 07:02
Please be informed that due to a hard failure impacting the Cnes/Ssalto echanges, the data delivery on the CNES FTP server may be affected. Actions are on going to resume to nominal situation. We apologize for the inconvenience
Categories: Climate Science News

CFOSAT: D-4 before the launch !

AVISO Climate Change News - Fri, 2018-10-26 00:30
The launch countdown is becoming clear at the Jiuquan Space Launch Center in China, with the Long March 2C rocket preparing for liftoff. Next Monday, 29th October 2018, the CFOSAT satellite will reach its sun-synchronous orbit at 520 km altitude. CFOSAT studies ocean surface winds and waves with a view to improving sea-state forecasts and gaining new insights into ocean-atmosphere interactions. Calibration/Validation and data processing after the launch

After about one month during the Commissioning Phase, the data will be available for scientific expert during the Calibration/Validation phase (represented in France by LATMOS, LOPS and marine forecasters and oceanographers at Météo-France). After 6-7 months, the data will be accessible to the entire scientific community. 

Chinese or French, each mission centre generates user products through two processing chains : one for SWIM data, the other for SCAT data. Each country designed and developed the scientific algorithms for its own intrument, capable of extracting physical values from the raw telemetry. Each then delivered its processing chain to the other partner for integration into the latter's operational mission centre.

The French Mission Centre supplies weather agencies with Level-1 and Level-2 products for marine weather forecasts in less than  3 hours. For other applications, France and China offer Level-3 and Level-4 value-added products.

These will be developed over longer timescales and incorporate external data, for use in research into subjects as ocean/atmosphere exchanges.

Thematic posters of CFOSAT. Credits CNES, CNSA. All posters on this page.

Further information: 
  • CFOSAT, all news about the launch:
    • 2018/10/19: What happens before the launch in 10 days?
    • 2018/10/11 : pre-launch workshop
    • 2018/10/14 : launch foreseen on October 29th, 2018
  • CFOSAT: Missions
  • Press release from CNES and CNRS (in french): Le CNES et le CNRS unissent leur expertise pour l’étude du changement climatique sur les océans
Categories: Climate Science News

[Jason-2] Jason-2 is back to nominal

AVISO Climate Change News - Thu, 2018-10-25 05:08
Today, October 25th, during last Usingen pass, all core-mission instruments have been restarted :
  • POSEIDON at 09:08:05UTC
  • AMR at 09:09:57UTC
  • GPSP at 09:12:48UTC
Jason-2 mission is then back to nominal activities at the end of cycle 609, after approximately 7 days of unavailability. The first telemetry will be available around 11:30UTC, right after the coming pass.
Categories: Climate Science News

[Jason 2] Jason 2 in Safe Hold Mode on October 19th at 11:41:34UTC

AVISO Climate Change News - Sun, 2018-10-21 23:29
On October 19th 2018 at 11:41:34UTC, Jason-2 entered in Safe Hold Mode due to the (now usual and expected) disjunction anomaly on Gyro 2. At that time, another anomaly, due to the corruption of the mass memory onboard was already preventing any products generation since October 18th around 11:11UTC. This memory corruption anomaly has no direct link with the gyro disjunction. Next week, investigations on the corruption anomaly will be carried on, and the SHM recovery schedule will be decided accordingly.  Operational teams are currently doing their best to recover the mission as soon as possible.
Categories: Climate Science News

CFOSAT : what happens before the launch in 10 days?

AVISO Climate Change News - Fri, 2018-10-19 07:01
In the framework of a cooperation between CNES and CNSA, the CFOSAT satellite will be launched on the 29th of October, 2018 from China using a Long March-2C launch vehicle. Ten days before the launch, all operations are nominal at the Jiuquan Space Launch Center: filling of the satellite hydrazine tank and their pressurization, detection of the possibility of leaks, battery charching, tests on the platform, SCAT and SWIM, process of finalization on the thermal protections on the satellite and SWIM instrument, solar panel manual deployment. The operations with the launcher will be pursue until the launch : encapsulation of the satellite into the payload fairing, connection with the launch vehicle, battery charging. Further information:
  • Missions: CFOSAT
Categories: Climate Science News

CFOSAT: pre-launch workshop

AVISO Climate Change News - Thu, 2018-10-11 06:14
This workshop was co-organized by CNES, CNRS, LATMOS, LOPS and IUEM with a wide participation of about 60 scientists : Chinese-French scientific community and for the first time, a significant number of foreign scientists coming worldwide. They showed a keen interest in future data and their applications. This workshop is undoubtedly the beginning of the scientists CALVAL operations in preparation to future data exploitation.

The main topics of the workshop were on:

  • CFOSAT data processing methods,
  • preparation of the geophysical CAL/VAL (calibration/validation) activity,
  • combined use of SWIM and SCAT observations,
  • scientific studies based on CFOSAT products,
  • synergetic use of CFOSAT products and data from other missions and sensors,
  • data assimilation in numerical models, operational model validation,
  • links with future satellite missions.
CFOSAT is an innovative satellite mission, which will carry two radar instruments (SWIM and SCAT). It will be launched on October 29th, 2018. CFOSAT studies ocean surface winds and waves with a view to improving sea-state forecasts and gaining new insights into ocean-atmosphere interactions. Thanks to the new types of observations that it will provide (directional wave spectra), it will also be a key element to prepare future oceanographic satellite missions such as those devoted to surface current measurements. CFOSAT is developed and will be exploited under a Chinese-French cooperation as agreed through the Chinese-French Memorendum of Understanding (MOU). More generally, a strong partnership with the international scientific community is wished to maximize the scientific return. Further information:
  • on the website of the pre-launch workshop
  • Missions: CFOSAT
Categories: Climate Science News

Arctic summer 2018: September extent ties for sixth lowest

NSIDC Artic Sea Ice News - Mon, 2018-10-08 13:15

After starting the year with record lows in January and February, Arctic sea ice extent ended tied with 2008 for the sixth lowest average September extent in the satellite record. The 2018 minimum extent was reached on both September 19 and 23. September 23 is among the latest dates for the seasonal minimum in the nearly 40-year satellite record. In the Antarctic, the annual maximum extent appears to have been reached on October 2.

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

Figure 1. Arctic sea ice extent for September 2018 was 4.71 million square kilometers (1.82 million square miles). The magenta line shows the 1981 to 2010 average 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 September 2018 averaged 4.71 million square kilometers (1.82 million square miles), tying with 2008 for the sixth lowest September in the 1979 to 2018 satellite record. This was 1.70 million square kilometers (656,000 square miles) below the 1981 to 2010 average, and 1.14 million square kilometers (440,000 square miles) above the record low recorded for September 2012. Prior to September 19, sea ice extent declined at a relatively rapid 14,440 square kilometers (5,580 square miles) per day, significantly faster than in most years. The near-zero loss rate between September 19 and 23, and the very late onset of significant seasonal ice growth after September 23, were atypical of the satellite record.

Sea ice loss during the first half of September primarily occurred within the East Siberian, northern Laptev, and northern Chukchi Seas, in part because winds from the south brought warm air into the region and inhibited ice from drifting or growing southward. Retreat in these areas was partially offset by ice expansion in the eastern Beaufort Sea and the northern Kara and Barents Seas. The old ice that had been persisting in the Beaufort Sea near Prudhoe Bay mostly melted out by the end of September. While the Northern Sea Route opened again this year, as it has every year since 2008, ice lingered in the central section of the southern route of the Northwest Passage between Bellot Strait and Gjoa Haven.

Since the seasonal minimum extent, reached on September 19 and again on September 23 at 4.59 million square kilometers (1.77 million square miles), ice cover has expanded in the Canadian Archipelago, the northern Chukchi and Beaufort Seas, and the East Greenland Sea, while retreating slightly within the Kara Sea.

Conditions in context

Figure 2a. The graph above shows Arctic sea ice extent as of October 07, 2018, along with daily ice extent data for four previous years and the record low year. 2018 is shown in blue, 2017 in green, 2016 in orange, 2015 in brown, 2014 in purple, and 2012 in dotted 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. This plot shows the difference from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for September 2018. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

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

September air temperatures at the 925 hPa level (about 2,500 feet above the surface) were from 3 to 8 degrees Celsius (5 to 14 degrees Fahrenheit) above average over the western Beaufort, Chukchi, and East Siberian Seas. As noted above, this delayed the seasonal onset of ice growth in these areas, seen in the late timing of the seasonal sea ice minimum for the Arctic as a whole, and the near-zero change in ice extent over the period September 19 to 23.

A very pronounced high pressure ridge contributed to this unusual warmth. The Capital Weather Gang reports that the high pressure ridge, which formed over the Bering Sea in early September, drifted eastward, became especially pronounced late in the month, and then expanded into the Beaufort and Chukchi Seas. This contributed to the slow freeze up after the minimum. Sunny, warm, and dry conditions spread across much of Alaska. Anchorage, Alaska experienced its warmest September on record. Air motion under a pressure ridge tends to be downwards, inhibiting the formation of clouds, rainfall, or snowfall.

 

September 2018 compared to previous years  National Snow and Ice Data Center| High-resolution image

Figure 3. Monthly September ice extent for 1979 to 2018 shows a decline of 12.8 percent per decade.

Credit: National Snow and Ice Data Center
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Sea ice extent for September 2018 fell just above the long-term linear trend line. The linear rate of sea ice decline for September is 82,300 square kilometers (32,000 square miles) per year, or 12.8 percent per decade relative to the 1981 to 2010 average.

A look back at the summer melt season Arctic air temperature ranking at 925 hPa based on NCEP/NCAR reanalysis for all areas north of 70oN. Credit: Zachary Labe/affiliation?

Figure 4a. This graphic ranks months based on their Arctic air temperature from 1979 to 2018 at 925 hPa from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis for all areas north of 70 degrees N. Dark reds indicate warmest months; dark blues indicate coldest months.

Credit: Z. Labe, University of California, Irvine
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Figure 4b. This true color composite shows the patch of sea ice off Point Barrow, north of Utqiaġvik, Alaska, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the NASA Terra satellite on September 19, 2018.

Credit: NASA Worldview
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Total sea ice extent reached record lows in January and February, and stayed at second lowest from March through May, largely due to extremely low extent in the Bering Sea. However, the September extent tied for sixth lowest in the record, slightly above the long-term trend line.

Melt began slowly over most of the western Arctic Ocean and the East Siberian Sea. As a result, despite June temperatures that were slightly above average (Figure 4a), the rate of ice loss in June of 52,800 square kilometers (20,000 square miles) per day was slightly below the 1981 to 2010 average of 56,300 square kilometers (22,000 square miles) per day. A cloudy and cool July followed, especially over the East Siberian Sea and stretching westward towards the Kara Sea. In response, ice was particularly slow to retreat in the East Siberian Sea. Indeed, July ranked as the ninth coldest July since 1979.

Puzzling in this regard is that the July ice decline rate of 105,400 square kilometers (41,000 square miles) per day, was considerably faster than the 1981 to 2010 average decline of 86,800 square kilometers (34,000 square miles) per day. Only in 2007 and 2009 did July have faster rates of ice loss. This is counter intuitive, and likely illustrates the importance of atmospheric processes in transporting ice northwards, and the role of ocean warmth in melting ice.

While July is usually the warmest month of the year, air temperatures this August exceeded those in July. This has only happened once before in the last 70 years, according to analysis of data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalyses. August air temperatures at the 925 hPa level were up to 5 degrees Celsius (9 degrees Fahrenheit) above average in the Laptev Sea. Still, the August ice loss of 57,500 square kilometers (22,000 square miles) per day was nearly identical to the 1981 to 2010 average decline. The large tongue of ice that had been persisting within the East Siberian Sea started to melt out. Above average air temperatures continued through early September, especially in the East Siberian Sea, which helped to further melt sea ice that had persisted all summer. By the end of the melt season, about 267,000 square kilometers (103,000 square miles) of ice remained in this sector. The least amount of sea ice within the East Siberian Sea was recorded in 2007 (2,980 square kilometers or 1,150 square miles). As discussed above, the late date of the sea ice minimum and the near-zero change in ice extent from September 19 to 23 reflects the influence of the very warm conditions associated with the high pressure ridge.

A patch of sea ice remained through the summer in the Beaufort Sea, northeast of Point Barrow, consisting of first-year ice interspersed with floes of more resistant multiyear ice. This patch was no longer detected in the passive microwave imagery once it became too sparse. However, ice was still evident through the end of the melt season in visible imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) (Figure 4b) and was charted in operational analyses from the Multisensor Analyzed Sea Ice Extent (MASIE).

In short, the reasons why September sea ice extent for 2018 ended up as sixth lowest, well above 2007 and 2012, remains to be fully determined. Melt onset was somewhat late, but despite cool conditions the July ice loss was rather rapid. The ice loss rate in August was near average. Further research is warranted.

The importance of ice age  M. Tschudi, S. Stewart, University of Colorado, Boulder, and W. Meier, J. Stroeve, NSIDC

Figure 5a. This map shows sea ice age category during week 38 in 2018, showing the origin of the patch of ice in the Beaufort Sea and the last remnant. The age category value designates the maximum age of that ice. Click here for the full animation.

Credit: M. Tschudi, S. Stewart, University of Colorado, Boulder, and W. Meier, J. Stroeve, NSIDC
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Figure 5b. This time series shows multiyear ice at the end of each summer melt season since 1985. Note that these images are based on an updated soon-to-be-released version of the current sea ice age product and a near-real-time version for 2018.

Credit: M. Tschudi, S. Stewart, University of Colorado, Boulder, and W. Meier, J. Stroeve, NSIDC
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Over a winter season, first-year ice can grow up to 1.5 to 2 meters (4.9 to 6.6 feet) thick. Ice that survives the summer season can grow through the next winter by ridging and rafting and additional thermodynamic ice growth to well over 3 meters (9.8 feet) thick. Multiyear ice has a better chance of surviving the following melt season. Multiyear ice moved into the Beaufort Sea from the northwest through the spring and summer as part of the Beaufort Gyre—a clockwise circulation of ice centered over the northern Beaufort Sea (Figure 5a). By contrast, the tongue of ice in the East Siberian Sea largely consisted of first-year ice. Overall, the amount of multiyear ice remaining at the end of summer (Figure 5b) is considerably lower than it used to be during the 1980s and 1990s. Now multiyear ice covers 2 million square kilometers (772,000 square miles) or less of the Arctic Ocean. The oldest ice, which has survived at least four melt seasons, used to cover nearly 1.5 million square kilometers (579,000 square miles). In 2018, this old ice covered only 94,000 square kilometers (36,0000 square miles) at the September minimum.

Antarctica’s wandering path to its seasonal maximum

Figure 6. The graph above shows Antarctic sea ice extent as of October 7, 2018, along with daily ice extent data for four previous years. 2018 is shown in blue, 2017 in green, 2016 in orange, 2015 in brown, and 2014 in dotted 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
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Antarctic sea ice may have reached its maximum extent on October 2, 2018, at 18.15 million square kilometers (7.01 million square miles). If the downward trend continues, it will be the fourth lowest maximum in the satellite record—higher than the 1986, 2002, and 2017 maxima. It is 180,000 square kilometers (70,000 square miles) above the record low Antarctic maximum set in 1986, at 17.97 million square kilometers (6.94 million square miles). It is also 560,000 square kilometers (216,000 square miles) below the 1981 to 2010 average maximum extent of 18.71 million square kilometers (7.22 million square miles). This year’s maximum date of October 2 is about nine days later than the 1981 to 2010 median date and ten days later than the 1981 to 2010 average date. With spring sunshine and warmth increasing daily, the likelihood of a major sea ice expansion is small. However, some years, as in 2002, the maximum was reached on October 12, the latest in the satellite record. There are also brief increases in ice extent as late as October 22 that do not result in new maxima.

In 2018, the Southern Ocean has been true to form. Overall, September sea ice extent has been at near-record lows over the period of satellite observations. A peak in ice extent early in September was followed by a steep decline through mid-month. By the third week of September, extent increased steadily. After a few days of minimal decline, extent reached its maximum on October 2.

Recent ice growth has occurred in the northernmost Ross Sea, partially offsetting ice losses in the area north of Dronning Maud Land and the Drake Passage. Temperatures from August 21 to September 20 at the 925 hPa level were 2 to 5 degrees Celsius (4 to 9 degrees Fahrenheit) above average over much of the ice edge in the Weddell and western Ross Seas. Cool conditions, with temperatures of 4 to 8 degrees Celsius (7 to 14 degrees Fahrenheit) below average, characterized the northern Bellingshausen Sea. Sea surface temperatures near the ice edge were near average except in the northern Bellingshausen Sea, where they have been 0.5 to 1.5 degrees Celsius (0.9 to 2.7 degrees Fahrenheit) lower than average.

Categories: Climate Science News

Copernicus Sentinel-3 improves observation of inland waters

AVISO Climate Change News - Fri, 2018-10-05 04:46
While world-class scientists are meeting in the Azores to discuss how satellites have revealed changes in the height of the sea, ice, inland bodies of water and more, the Copernicus Sentinel-3 satellite has new reasons to shine. Radar altimeters record the surface topography along the satellite's ground track. They precisely measure the height of water, land and ice by timing the interval between the transmission and reception of very short radar pulses. This is the only technology that can measure, systematically and globally, changes in the height of the ocean - and is therefore essential for monitoring sea-level rise. After a successful commissioning phase (flying 30 seconds apart in tandem with its twin Sentinel-3A), the Sentinel-3B satellite of the European Union's Copernicus Programme will be moved, in October, to its final orbit. During this drift period, the altimeter will be uploaded with new Open-Loop Tracking Command (OLTC) tables, which are used to control the return echo acquisition phase of the altimeter by setting its reception window. This on-board process ensures recording reliable and quality measurements over inland waters. These tables have been upgraded with more than 32,500 virtual stations defining lakes, reservoirs, rivers and even glaciers worldwide, as shown on the featured image. More information here.
Categories: Climate Science News

22 September - 5 October 2018 Weeks

AVISO Climate Change News - Fri, 2018-10-05 02:07
The new normal? How climate change is making droughts worse (The Guardian, 03/10/2018) ICESat-2 laser fires for first time, measures Antarctic height (EurekAlert!, 03/10/2018) A rare combination of Category 5 storms in the Pacific (Axios, 02/10/2018) What caused the Indonesia tsunami and could lives have been saved? (The Guardian, 02/10/2018) Terrawatch: why did the quake in Sulawesi cause a tsunami? (The Guardian, 02/10/2018) Scientists solve a Southern Ocean climate change mystery (Axios, 28/09/2018) What pushed 2017’s Atlantic hurricane season into overdrive? (Ars Technica, 28/09/2018) New research shows the world’s ice is doing something not seen before (The Guardian, 26/09/2018) How reliable are turtles for measuring ocean trash and marine health? (Science Daily, 26/09/2018) A vast wall in Antarctica could slow rising seas, but some scientists are wary of the idea (NBC news, 26/09/2018) European Space Agency shining the spotlight on sea-level rise (Digital Journal, 25/09/2018) Liquid climate archives: A study on tide levels in the straits (Phys.org, 25/09/2018) Earth from Space - São Miguel, Azores (Spaceref, 21/09/2018) Au Bangladesh, les eaux avancent, les hommes reculent (L'Obs, 04/10/2018) Le Portugal se dote d'une base spatiale aux Açores (Sciences & avenir, 02/10/2018) Réchauffement climatique. Comment garder la tête hors de l’eau ? (Courrier International, 02/10/2018) Les côtes arctiques franchies pour la première fois par la Marine française (Sciences & avenir, 02/10/2018) Climat : limiter la hausse des températures à 1,5°C, est-ce possible ? (Sciences & avenir, 01/10/2018) Le Japon balayé par le typhon Trami et ses rafales à 216 km/h (Le Monde, 30/09/2018) Australie: une célèbre plage avalée par la mer (L'Express, 26/09/2018) Cent jours sans gel au Pic du Midi: un nouveau record historique (Sciences & avenir, 22/09/2018) 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

October 2018: A new satellite to measure winds and waves

AVISO Climate Change News - Fri, 2018-10-05 00:46
CFOSAT launch is planned on Oct. 29, 2018. Some ideas of what this brand-new satellite concept will...
Categories: Climate Science News

September 2018: A buoy trapped in filaments

AVISO Climate Change News - Fri, 2018-10-05 00:44
Sometimes drifting buoys stay around the same point. FSLE can help interpret this.
Categories: Climate Science News
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