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
High-resolution image

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
High-resolution image

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
High-resolution image

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
High-resolution image

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
High-resolution image

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
High-resolution image

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

New release of the Finite-Size Lyapunov Exponents (FSLEs)

AVISO Climate Change News - Thu, 2018-10-04 02:34
The maps of Backward-in-time, Finite-Size Lyapunov Exponents (FSLEs) and Orientations of associated eigenvectors have been updated after a whole reprocessing from January 1st 1994 to January 18th 2018. Data are computed over global ocean within the SALP/Cnes project in collaboration with CLS, LOcean and CTOH. The main upgrades for this reprocessing are the following:
  • madt_uv input data are derived from DUACS DT2018 instead of DUACS DT2014.
  • Data are available daily from 01-01-1994 to 18-01-2018
  • Initial separation is 0.02 degree instead of 0.04 degree. The filaments are much thinner.
Data format remains unchanged. More information can be found on the product page.  Data are available on FTP and on Gridded Data Extraction tool from : My AVISO+ web page.

FSLE DUACS 2018 compare to FSLE DUACS 2014 credit CNES/CLS

Link to the video here
Categories: Climate Science News

New release of the Mesoscale Eddy Trajectory Atlas

AVISO Climate Change News - Thu, 2018-09-27 18:00
This dataset includes the tracks of eddies detected and monitored in the multimission "2-satellite" delayed-time DUACS products with additional information such as speed, radius, or eddy type (cyclonic/anticyclonic). This experimental version 2.0 takes into account the new DUACS2018 dataset (Jan 93 to Jan 18) and include some improvements in the tracking process. Complete information on the product page.
Categories: Climate Science News

Arctic sea ice extent arrives at its minimum

NSIDC Artic Sea Ice News - Thu, 2018-09-27 08:00

On September 19 and 23, Arctic sea ice appeared to have reached its seasonal minimum extent for the year, at 4.59 million square kilometers (1.77 million square miles). This ties 2018 with 2008 and 2010 for the sixth lowest minimum extent in the nearly 40-year satellite record. 

Please note that this is a preliminary announcement. Changing winds or late-season melt could still reduce the Arctic ice extent, as happened in 2005 and 2010. NSIDC scientists will release a full analysis of the Arctic melt season, and discuss the Antarctic winter sea ice growth, in early October.

Overview of conditions

Figure 1a. Arctic sea ice extent for September 23, 2018 was 4.59 million square kilometers (1.77 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

 National Snow and Ice Data Center High-resolution image

Figure 1b. The map above compares Arctic sea ice extent on September 19, 2018 and September 23, 2018, when Arctic sea ice reached its minimum extent for the year. Sea Ice Index data. About the data

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

On September 19 and 23, 2018, sea ice extent dropped to 4.59 million square kilometers (1.77 million square miles), tying for the sixth lowest minimum in the satellite record along with 2008 and 2010. This appears to be the lowest extent of the year. In response to the setting sun and falling temperatures, ice extent will begin expanding through autumn and winter. However, a shift in wind patterns or a period of late season melt could still push the ice extent lower.

The minimum extent was reached 5 and 9 days later than the 1981 to 2010 median minimum date of September 14. The interquartile range of minimum dates is September 11 to September 19. This year’s minimum date of September 23 is one of the latest dates to reach the minimum in the satellite record, tying with 1997. The lateness of the minimum appears to be at least partially caused by southerly winds from the East Siberian Sea, which brought warm air into the region and prevented ice from drifting or growing southward.

This year’s minimum extent ranked behind 2015 (fifth lowest), 2011 (fourth lowest), 2007 and 2016 (tied for second lowest), and 2012 (lowest). Moreover, the twelve lowest extents in the satellite era have all occurred in the last twelve years.

Conditions in context

Figure 2. The graph above shows Arctic sea ice extent on September 23, 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

This year’s minimum set on September 23 was 1.20 million square kilometers (463,000 square miles) above the record minimum extent in the satellite era, which occurred on September 17, 2012, and 1.63 million square kilometers (629,000 square miles) below the 1981 to 2010 average minimum extent.

Twelve lowest minimum Arctic sea ice extents (satellite record, 1979 to present) Table 1. Twelve lowest minimum Arctic sea ice extents (satellite record, 1979 to present) RANK YEAR MINIMUM ICE EXTENT DATE IN MILLIONS OF SQUARE KILOMETERS IN MILLIONS OF SQUARE MILES 1 2012 3.39 1.31 Sept. 17 2 2007
2016 4.16
4.17 1.61
1.61 Sept. 18
Sept. 10 4 2011 4.34 1.68 Sept. 11 5 2015 4.43 1.71 Sept. 9 6 2008
2018
2010 4.59
4.59
4.62 1.77
1.77
1.78 Sept. 19
Sept. 19 & 23
Sept. 21 9 2017 4.67 1.80 Sept. 13 10 2014
2013 5.03
5.05 1.94
1.95 Sept. 17
Sept. 13 12 2009 5.12 1.98 Sept. 13

Values within 40,000 square kilometers (15,000 square miles) are considered tied. The 2017 value has changed from 4.64 to 4.67 million square kilometers (1.80 million square miles) when final analysis data updated near-real time data.

Categories: Climate Science News

Live: 25 years of radar altimetry

AVISO Climate Change News - Fri, 2018-09-21 02:50
The opening session of the 25 Years of Progress in Radar Altimetry (Mon 24 Sep 08:55-13:00 UTC) will be live streamed for those who cannot unfortunately attend this event: http://www.esa.int/Our_Activities/Observing_the_Earth/Live_25_years_of_radar_altimetry
or
http://www.esa.int/live You can view and download the full program at: https://www.altimetry2018.org/ 
Categories: Climate Science News

10 - 21 September 2018 weeks

AVISO Climate Change News - Fri, 2018-09-21 02:00
Keeping score on Earth's rising seas (Nasa's Sea Level, 18/09/2018) Hurricane Florence is a climate change triple threat (The Guardian , 14/09/2018) ICESat-2: Tracking Earth's Ice with Unparalleled Detail (Space.com, 13/09/2018) Antarctique : l’un des plus grands icebergs jamais vus prend le large (Futura Sciences, 18/09/2018) La NASA lance un laser en orbite pour mesurer la fonte des glaces (Le Monde, 15/09/2018) Comment les ouragans sont-ils classés ? (Le Monde, 12/09/2018) Météo: 70% de probabilité d'un phénomène El Niño à la fin de l'année (Sciences & avenir, 10/09/2018) 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

Nearing the Arctic’s seasonal minimum

NSIDC Artic Sea Ice News - Wed, 2018-09-19 13:00

The seasonal minimum of Arctic sea ice extent is imminent; extent at the minimum is likely to be the sixth lowest in the satellite record, tied with 2008.

Overview of conditions Figure 1. Arctic sea ice extent for September 17, 2018 was 4.60 million square kilometers (1.78 million square miles). The orange line shows the 1981 to 2010 average extent for that day.

Figure 1. Arctic sea ice extent for September 17, 2018 was 4.60 million square kilometers (1.78 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

On September 17, Arctic sea ice extent stood at 4.60 million square kilometers (1.78 million square miles). This was 1.69 million square kilometers (653,000 square miles) below the 1981 to 2010 long-term average extent for this day of year, but 1.21 million square kilometers (467,000 square miles) above the record low for this day of year set in 2012. With the onset of autumn, air temperatures are dropping across the Arctic. The seasonal minimum extent is imminent. The Arctic’s minimum sea ice extent is likely to be the 6th lowest in the 39-year satellite record. Cool conditions in July played a large role in slowing the rate of summer ice loss. The Northern Sea Route nevertheless appears to be navigable. The Northwest Passage, including both the Northern and Southern routes, will not open this year. A remnant island of sea ice north of Alaska—well separated from the main area of pack ice and discussed in our previous post—is almost certain to survive the melt season.

Conditions in context Figure 2a. The graph above shows Arctic sea ice extent as of September 17, 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.

Figure 2a. The graph above shows Arctic sea ice extent as of September 17, 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 departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for September 1 to 16, 2018. Yellows and reds indicate higher than average temperatures; blues and purples indicate lower than average temperatures.

Figure 2b. This plot shows the difference from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for September 1 to 16, 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

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

Figure 2c. This plot shows the average sea level pressure in the Arctic, in degrees Celsius, for September 1 to 16, 2018. Yellows and reds indicate higher than average air pressures; blues and purples indicate lower than average air pressures.

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

The average rate of ice loss from September 1 through September 17 was 25,000 square kilometers per day (10,000 square miles per day), similar to average rate of loss for the first half of September over the period 1981 to 2010. Sea ice retreat primarily occurred in the northern Chukchi, East Siberian, and Laptev Seas. The ice edge retreated slightly in the Kara and Barents Seas. Air temperatures at the 925 hPa level (about 2,500 feet above the surface) were near average over much of the Arctic Ocean, the obvious exception being in the East Siberian Sea, where temperatures were as much as 7 to 9 degrees Celsius (13 to 16 degrees Fahrenheit) above average. These high temperatures helped to reduce the sea ice extent in this region. The sea level pressure pattern for this same period is dominated by an area of low pressure extending from central Siberia, across the pole, and into the Canadian Arctic, and is most pronounced north of the Laptev Sea. The feature north of the Laptev Sea, in conjunction with the area of high pressure centered over the Bering Sea, has acted to transport warm air from the south over the East Siberian Sea, helping to explain the high temperatures there.

Categories: Climate Science News

Hurricane Florence and Typhoon Mangkhut

AVISO Climate Change News - Wed, 2018-09-19 02:37
Satellite altimetry data from Sentinel-3A measured the Significant Wave Heights during the passage of these storms (see Figure 1 below):
  • more than 5 m at 10-25 km off the North and South Carolina coasts on 13 and 14 September (respectively for the ground tracks 678 and 691) while the hurricane Florence crossed this area. A peak at almost 7m was measured on 13 Sept. at ~70 km off the coasts.
  • more than 10 m at only 16 km off the Hong-Kong coasts was measured on 15-16 September (respectively for the ground tracks 733 and 748).
The SAR on the Sentinel-1B satellite provided wind fields while the super typhoon Mangkhut was heading towards southeast Asia with a maximum wind speed reaching 288 km/h on 11 September (see Figure 2 at the bottom). The upcoming launch of the Chinese-French CFOSAT satellite scheduled on 2018/10/29 will allow accurate ocean forecasts during such extreme events by collecting data both on wind speed and wave height.

Fig. 1 : Significant Wave Heights (H1/3, in meters) measured along-track by Sentinel-3A during hurricane Florence (left) and typhoon Mangkhut (right), during the passage of the storms, on September 2018.

The maps plots all the tracks between 10-14 Sept. for Florence and 15-17 Sept. for Mangkhut. The plots at the bottom only show the SWH nearest the passage of the storms off the coasts (x-axis indicates the distance to the coast in km for each track).

Credits EU Copernicus Marine Service for the data, produced by AVISO+.

Fig.2: Ocean surface wind speed map measured by Sentinel-1B on 2018/0911 while the typhoon Magkhut was in Category 5. Maximum wind speed reached more than 80m/s (288km/h). The ocean fields are given by the Sentinel-1 SAR on its Extended Wide Swath mode. The swath about 400 km-width are visible on the map. Credits Sentinel-1B: Contains modified Copernicus Sentinel data 2018 processed by IFREMER/CLS. 

Further information
  • CFOSAT
    • page Missions
    • video presentation of the CFOSAT project (posted by CNES)
  • on Copernicus Marine Service website: Looking at hurricane Florence through wave height with model data.
  • Data access:
    • Significant wave heigths from Sentinel-3A, European Copernicus Marine Service
Categories: Climate Science News

CFOSAT : launch foreseen on October 29th, 2018

AVISO Climate Change News - Fri, 2018-09-14 09:40
CFOSAT, China France Oceanography SATellite, operated by CNES and CNSA, is devoted to ocean surface wind and wave observation. The CFOSAT Joint System Review & PSR will take place from the 15th to the 18th of September, after which the launch campaign will start until the launch on October 29th.   To learn more about the mission and the instruments:
  • Missions: CFOSAT
  • CFOSAT on the Cnes space scientific missions web site
  • Multimedia: Seven posters to know more about the mission and the French (Swim for measuring waves) and Chinese (Scat for measuring global sea level surface wind) instruments
Categories: Climate Science News

1 - 9 September 2018 week

AVISO Climate Change News - Wed, 2018-09-12 03:44
China launches satellite to monitor world’s oceans (Spaceflight now, 09/09/2018) Increasing odds that Tropical Storm Florence will threaten East Coast (Axios, 07/09/2018) Climate change could affect human evolution. Here's how. (NBC news, 07/09/2018) Scientists find the reason why part of West Antarctic ice is thickening (Knowridge, 07/09/2018) World's biggest sovereign fund in Norway urges companies to help save oceans (First Post, 06/09/2018) Melting glaciers increasing risk of landslide-triggered tsunamis, study reveals (The independent, 06/09/2018) Massive Ocean Waves May Play a Role in Nuisance Flooding (EOS, 04/09/2018) Y a-t-il vraiment 5 continents de plastique dans les océans ? (Libération, 07/09/2018) 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

Aviso+ Users Newsletter #15

AVISO Climate Change News - Mon, 2018-09-10 05:35
We are pleased to announce you the publication of the fifteenth  Aviso+ Users Newsletter :  CONTENTS: 
  • Project News: Ongoing and forthcoming missions, ongoing developments
  • Aviso+ User Satisfaction Survey 2018 : What are you telling us ?
  • Toward a new generation of DUACS products with finer resolution
  • Events
Find all the past newsletters here.
Categories: Climate Science News

[Sentinel-3A L2P] redelivery of NTC Sentinel-3A cycle 24 on September 6th 2018

AVISO Climate Change News - Thu, 2018-09-06 07:07
Please, be informed that the cycle 24 of the NTC Sentinel-3A L2P products covering the period between 16/11 to 23/11/2017 has been redelivered.
Indeed, following the installation of the new software version, the values of the SLA bias were not correct.
The files from version 02_00 named global_sla_l2p_ntc_s3a_C0024_P*_201711*_20180823*.nc.gz have been redelivered with the corrected variables 'inter_mission_bias' and 'sea_level_anomaly' We apologize for the inconvenience.
Categories: Climate Science News

No endless summer in the Arctic

NSIDC Artic Sea Ice News - Tue, 2018-09-04 11:19

With the waning of Arctic summer, the seasonal decrease in sea ice extent has slowed. At this time of the year, the extent is the highest it has been since 2014. Nevertheless, sea ice extent remains well below the interdecile range (lowest 10 percent for ice extent years). The minimum is expected to be one of the ten lowest in the satellite record.

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

Figure 1. Arctic sea ice extent for August 2018 was 5.61 million square kilometers (2.17 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 August 2018 averaged 5.61 million square kilometers (2.17 million square miles). This was 1.59 million square kilometers (614,000 square miles) below the 1981 to 2010 long-term average sea ice extent, and 890,000 square kilometers (344,000 square miles) above the record low for the month set in August 2012. August 2018 was the seventh lowest August extent in the satellite record, but the highest August extent since 2014.

At the end of the month, sea ice extent stood at 4.97 million square kilometers (1.92 million square miles). Sea ice extent remained low along the coastal seas of the Arctic Ocean with the exception of the East Siberian Sea. The Northern Sea Route nevertheless appears to be navigable. Low sea ice concentrations persist in the northern Beaufort and Laptev Seas; these areas may still retreat further north before the melt season ends. The Northwest Passage is still choked with ice and is likely to remain so.

Conditions in context

Figure 2a. The graph above shows Arctic sea ice extent as of September, 4, 2018, along with daily ice extent data for four previous years and 2012, the year with record low minimum extent. 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 departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for August 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

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

Figure 2c. This plot shows average sea level pressure in the Arctic, in millibars, for August 2018. Yellows and reds indicate higher than average sea level pressure; blues and purples indicate lower than average sea level pressure.

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

The average ice loss rate for August was 57,500 square kilometers (22,200 square miles) per day. This was slightly faster than the 1981 to 2010 average, but substantially slower than August loss rates in recent years, particularly 2008, 2012, 2015, and 2016.

Air temperatures at the 925 hPa level (about 2,500 feet above sea level) were up to 4 degrees Celsius (7 degrees Fahrenheit) above average over much of the Arctic Ocean and the Laptev Sea, but up to 4 degrees Celsius (7 degrees Fahrenheit) below average over the Canadian Archipelago (Figure 2b). Higher temperatures over the ocean were related to high sea level pressure east of the Laptev Sea and low pressure over the Barents and Kara Seas, funneling in warm air from Eurasia (Figure 2c).

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

Figure 3. Monthly August ice extent for 1979 to 2018 shows a decline of 10.4 percent per decade.

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

The linear rate of decline for August sea ice extent is 75,000 square kilometers (29,000 square miles) per year, or 10.4 percent per decade relative to the 1981 to 2010 average. Ice loss during the month was 1.78 million square kilometers (687,000 square miles), which is nearly the same as the 1981 to 2010 average August decrease.

Sea ice off the Alaskan coast

Figure 4. This map of the Arctic Ocean shows sea surface temperatures (SST) from the University of Washington Polar Science Center UpTempO project. The image shows SSTs from the National Oceanic and Atmospheric Administration (NOAA) and sea ice concentrations from the National Snow and Ice Data Center (NSIDC). The numbered circles denote the location of UpTempO buoys, which are measuring the temperature in the near-surface ocean layer. Data from the buoys is available from the UpTempO website.

Credit: University of Washington
High-resolution image

Ice that has persisted along the Alaskan coast is starting to rapidly disintegrate. However, some remnants consist of thick floes. Sea surface temperatures obtained from the University of Washington’s UpTempO website indicate that waters in the area are near the freezing point. As such, some ice in this region may survive the melt season. These temperatures are consistent with those collected during the cruise of the South Korean icebreaker Aaron (see From the field, a wrap up below). Sea surface temperatures ranged between -1 and +1 degrees Celsius (30 and 34 degrees Fahrenheit) when the ship was traveling through the ice, and more than 4 degrees Celsius (39 degrees Fahrenheit) within the open waters of the Chukchi and Bering Seas.

Opening north of Greenland, closed Northwest Passage

Figure 5a. This map shows sea ice conditions in the western part of the Canadian Archipelago. The colors in the color bar correspond to sea ice concentration in tenths. Dark blue is low concentration (less than 10 percent), white is high concentration (100 percent).

Credit: Canadian Ice Service
High-resolution image

Figure 5b. This chart shows total sea ice area for selected years and the 1981 to 2010 average within the northern route of the Northwest Passage. The dotted red line shows 2018 and the other colors show ice conditions in different years.

Credit: Canadian Ice Service
High-resolution image

As noted in our previous post, an unusual area of open water formed off the northern coast of Greenland. It reached a maximum size of about 23,000 square kilometers (about 8,900 square miles) in mid-August—about the size of the state of New Jersey or the country of Wales. The opening has closed somewhat since then, but an ice-free region remains east of Cape Morris Jesup.

In contrast to northern Greenland, substantial amounts of ice remain in the channels of the Canadian Archipelago, thus the Northwest Passage is not open (Figure 5a). As of the end of August, sea ice area in the northern route of the Northwest Passage is currently tracking just above the 1981 to 2010 average (Figure 5b). The region is far from being free of sea ice; high ice concentrations are still present, about half of which is multiyear ice. Below average air temperature over the western Canadian Arctic Archipelago has limited ice melt. Low sea level pressures over the Beaufort Sea and Canadian Basin have packed ice against the western entrance of the Northwest Passage. The southern route of the Northwest Passage also contains relatively high ice concentrations, although mainly first-year ice. In the unlikely event that the southern route does open in the coming weeks it will be short-lived since multi-year ice from the northern regions would quickly move southward to fill the open water gaps.

From the field, a wrap up Figure 6. Snow depth from August 20 to August 30, 2018 as recorded from two MetOcean snow buoys deployed by NSIDC researcher Julienne Stroeve.

Figure 6a. These graphs show the evolution of snow depth, in meters, from August 20 to August 30, 2018 as recorded by two MetOcean snow buoys, which NSIDC scientist Julienne Stroeve deployed.

Credit: J. Stroeve, NSIDC
High-resolution image

Figure 6b. This photograph shows the MetOcean Snow Buoy set up on Arctic sea ice in the Chukchi Sea.

Figure 6b. This photograph shows the MetOcean Snow Buoy set up on sea ice in the Chukchi Sea.

Credit: J. Stroeve, NSIDC
High-resolution image

Figure 6c. NSIDC researcher Alia Khan collects snow samples for black carbon analysis, snow grain size, and snow depth. These measurements were collected in conjunction with spectral albedo measurements.

Figure 6c. NSIDC scientist Alia Khan collects snow samples for black carbon analysis, and measures snow grain size, snow depth, and spectral albedo.

Credit: A. Khan, NSIDC
High-resolution image

NSIDC scientists Julienne Stroeve and Alia Khan have returned from their Arctic expedition on the South Korean icebreaker Aaron. Both successfully deployed their instruments and collected scientific measurements. Now the work of data analysis begins. Since the buoy deployment by Stroeve and others, two of the melt pond buoy systems have already shown 20 centimeters (7.9 inches) of ice melt. Both snow buoys deployed by Stroeve (Figure 6b) are sending back good data (Figure 6a), with a mean snow depth for the last ten days in August of around 9.5±3.3 centimeters (3.74±1.3 inches for buoy #1 and 8.6±1.8 centimeters (3.4±0.7 inches) for buoy #2. While snow depth at the second buoy remained relatively constant, buoy #1 shows the effect of a snowfall event that likely occurred on August 30. Both buoys have drifted considerably eastwards since deployment, with buoy #1 drifting 104 kilometers (65 miles) in ten days (from 79.0 degrees N, longitude 164.5 degrees W to 79.0 degrees N, longitude 159.6 degrees W), and buoy #2 drifting 132 kilometers (82 miles) in nine days (from 78.4 degrees N, longitude 167.9 degrees W to 78.5 degrees N, longitude 162.0 degrees W).

Khan collected snow and ice samples (Figure 6c) for the analysis of black carbon (BC), which comes from the incomplete combustion of biomass and fossil fuels. When the dark particles are deposited on snow and ice surfaces, they absorb more solar radiation than the surrounding surface, reducing the albedo and enhancing melt. Over the course of the five-day ice camp, her team collected 133 snow samples. The team is interested in exploring local BC signals from shipping traffic, transport and deposition from regional Arctic wildfires, and background concentrations of long-range atmospheric transport of BC. They will compare BC concentrations in snow and sea ice with spectral albedo measurements, as well as results from a global aerosol atmospheric transport model to look at potential source regions of the aerosols.

Antarctic Report Figure 7. Daily Antarctic sea ice extent for the austral winter season from the past seven years (2012-2018) and the 1981-2010 median, and interquartile and interdecile ranges.

Figure 7. This graph shows daily Antarctic sea ice extent for the austral winter season from the past seven years, 2012 to 2018. 2012 is shown in red, 2013 in a dashed green line, 2014 in solid green, 2015 in yellow, 2016 in magenta, 2017 in purple, and 2018 in orange. 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.

Credit: NSIDC
High-resolution image

Antarctic sea ice has increased at a faster-than-average pace in the later part of August. The sea ice maximum is typically reached in late September. Overall sea ice extent is still in the bottom quartile (the lowest 25 percent of years) of the satellite record (Figure 7). Ice extent is below the median of the past 40 years in several regions, including the northern Weddell, far northeastern Weddell, and southern Indian Ocean.

The past seven austral winter seasons for Antarctic sea ice extent have been remarkably variable. In 2012, 2013, and 2014, Antarctic sea ice extent set consecutive satellite-era record highs for the annual maximum. However, 2015 had a near-average seasonally maximum ice extent, while 2016 saw ice extent plunge in late August to reach unprecedented low levels by austral spring in November. Since 2016, ice has remained below the 1981 to 2010 average extent, setting the second-lowest winter maximum extent in October 2017.

Categories: Climate Science News

6 - 31 August 2018 weeks

AVISO Climate Change News - Mon, 2018-09-03 09:14
The Most Powerful Storm of 2018 Is Headed Toward Japan (Earther, 31/08/2018) How a Battle to Build the Best Weather Model Impacts Everyone on Earth (Earther, 30/08/2018) Future impacts of El Niño, La Niña likely to intensify, increasing wildfire, drought risk (National Science Foundation, 28/08/2018) Arctic’s strongest sea ice breaks up for first time on record (The Guardian, 21/08/2018) Why sea level rise varies from place to place (Science News, 15/08/2018) Humans are pushing the Earth closer to a climate cliff (The Guardian, 15/08/2018) Jakarta is slowing sinking into the Earth (World Economic Forum, 15/08/2018) Jakarta, the fastest-sinking city in the world (BBC, 13/08/2018) From greenhouse to hothouse: the language of climate change (The Guardian, 09/08/2018) Pollution is slowing the melting of Arctic sea ice, for now (The Guardian, 03/08/2018) Le Libé des Océans (Libération, 31/08/2018) The Ocean Cleanup va déployer son premier barrage anti-déchets dans l’océan Pacifique-Nord ! (Science Post, 31/08/2018) La couche de glace la plus solide et la plus ancienne de l’arctique se fracture (Science Post, 26/08/2018) Mystère du triangle des Bermudes : l'hypothèse des vagues scélérates (Futura Science, 18/08/2018) Canicules : ça chauffe aussi très fort pour les océans (Le Nouvel Obs, 16/08/2018) 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

World Water Week - 26 – 31 August, 2018

AVISO Climate Change News - Thu, 2018-08-30 01:12
an international meeting on globe’s water issues
Categories: Climate Science News
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