Climate Science News

Approaching autumn, pace slows

NSIDC Artic Sea Ice News - Wed, 2018-08-15 11:11

After declining rapidly through July, sea ice extent decline slowed during the first two weeks of August. A new record September minimum is highly unlikely. Our 2018 projection for the sea ice minimum extent falls between the fourth and ninth lowest in the 39-year satellite record. Two NSIDC scientists are studying ice and ocean conditions in the western Arctic aboard an icebreaker.

Overview of conditions

Figure 1. Arctic sea ice extent for August 15, 2018 was 5.7 million square kilometers (2.2 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

As of August 15, Arctic sea ice extent was 5.7 million square kilometers (2.2 million square miles). This is 1.58 million square kilometers (610,000 square miles) below the 1981 to 2010 average, but 868,000 square kilometers (335,000 square miles) above the record low at this time of year recorded in 2012. Ice retreated recently in the Kara, Laptev, and Beaufort Seas. The ice edge was relatively unchanged near Greenland and Svalbard, and in the East Siberian Sea. Much of the Northwest Passage through Canada remains choked with ice. The Northern Sea Route appears open, according to the Multisensor Analyzed Sea Ice Extent (MASIE) analysis, though ice is lingering near the coast in the East Siberian Sea. Scattered ice floes are likely present along the route. A large patch of sea ice, separated from the main pack, persists in the southern Beaufort Sea. Such patterns of ragged patchiness or large polynyas have been a more frequent feature of Arctic summers since 2006.

Conditions in context

Figure 2a. The graph above shows Arctic sea ice extent as of August 15, 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 red. 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 average sea level pressure in the Arctic, in millibars, for August 1 to 14, 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

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

Figure 2c. This plot shows departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for August 1 to 14, 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

This a true-color composite from MODIS on the NASA Terra satellite. August 13, 2018.

Figure 2d. This shows a true color composite image of Cape Morris Jesup off of northern Greenland, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the NASA Terra satellite on August 13, 2018.

Credit: W. Meier, NSIDC/NASA
High-resolution image

Through the first two weeks of August, ice extent declined at approximately 65,000 square kilometers (25,100 square miles) per day, slightly faster than the 1981 to 2010 average of 57,000 square kilometers (22,000 square miles) per day. Sea level pressure was above average over the central Arctic Ocean, a change from last month, flanked by areas of below-average pressure in the Kara Sea and northern Canada (Figure 2b). Temperatures at 925 hPa (about 2,500 feet altitude) were generally 1 to 5 degrees Celsius (2 to 9 degrees Fahrenheit) above average over much of the Arctic Ocean for this period, with the area just north of Greenland reaching 5 to 7 degrees Celsius (9 to 13 degrees Fahrenheit) above average (Figure 2c). Below average air temperatures persisted over the Kara Sea, 1 to 3 degrees Celsius (2 to 5 degrees Fahrenheit), and the Beaufort Sea, 1 to 5 degrees Celsius (2 to 9 degrees Fahrenheit). Another feature of note is the region of open water (Figure 2d) along the north coast of Greenland, around Cape Morris Jesup, which is visible on August 13 in Moderate Resolution Imaging Spectroradiometer (MODIS) Terra true color imagery from NASA WorldView. The region normally consists of thick, consolidated ice from a general pattern of on-shore ice motion. Even when winds blow offshore, the strength of the thick ice would hold in place along the coast. However, current ice conditions appear more broken up and likely thinner, and over the past couple of weeks, offshore winds have succeeded in pushing ice off of the coast.

Estimating the September minimum extent

Figure 3. This graph shows potential sea ice minimum extents for 2018 based on ice loss rates from previous years. 2018, through August 15, is shown in blue. Projections based on 2008 rates are shown in purple dots, and 2006 rates are shown in blue dots.

Credit: W. Meier, NSIDC
High-resolution image

A simple way to project the upcoming annual minimum extent involves using the daily rates of change from previous years and applying them to the current sea ice extent. Following the 2005 to 2017 average rate of change between August 15 and the minimum, the extent is projected to drop to an annual low of 4.55 million square kilometers (1.76 million square miles), with a standard deviation range of 4.32 to 4.78 million square kilometers (1.67 to 1.85 million square miles). If sea ice extent continues at the rate of ice loss seen in 2008, the fastest recorded, the minimum at the end of summer would be 4.20 million square kilometers (1.62 million square miles), or the fourth lowest minimum in the satellite record. If sea ice extent continues with the rate for ice loss from 2006, the slowest recorded, the minimum would be 4.90 million square kilometers (1.89 million square miles), or the ninth lowest in the satellite record. It is possible that the rate of change through the remaining summer will be unprecedented in the satellite record (either faster or slower), yielding a final minimum extent outside of this range, but our estimates provide a window of the most likely minimum extent this year. Another possibility is that winds will consolidate the ice and reduce the overall extent. This was a factor contributing to the record low recorded in 2012.

Sea ice up close and personal 00 UTC) at 76N/179W, shows dirty ice amidst bright white ice. Photo credit: J. Stroeve

Figure 4a. This photograph, off the starboard side of the RV Araon on August 9, 2018 (21:00 UTC) at 76 degrees N and 179 degrees W, shows dirty ice amidst bright white ice.

Credit: J. Stroeve, NSIDC
High-resolution image

 A. Khan ||

Figure 4b. The team’s first sighting of a polar bear.

Credit: A. Khan, NSIDC
High-resolution image

Two NSIDC scientists are currently aboard the Korean icebreaker Araon as it travels through the Chukchi Sea. NSIDC scientist Julienne Stroeve wants to better understand how changes in the sea ice regime (e.g. ice thickness, snow depth, date of melt onset) influence the availability of sunlight under the ice, which plays a key role in phytoplankton blooms and grazing habits of zooplankton. Another objective is to quantify how layering of salty and fresh water in melt ponds evolves over time. To meet these objectives, the researchers will deploy several instrumented to measure seasonal snow accumulation, salinity, and temperature within selected salty and fresh melt ponds. A bio-optical buoy will measure the light and oxygen below the ice, and other buoys will measure the ice growth and melting on different types of ice floes.

As the icebreaker travels through the Arctic Ocean, NSIDC scientist Alia Khan is measuring the amount of sunlight that reaches the ice surface to assess the accuracy of incoming solar energy from weather models. Additionally, she is collecting atmospheric aerosol particles, such as smoke and dust, to measure their size distribution. On the ice, she will collect spectral reflectance measurements (reflectance of the surface in different solar energy wavelengths) of different ice types, such as thin first-year versus thick multiyear ice, snow-covered versus bare ice, and melt ponds. Lastly, she will collect snow and ice samples for analysis of black carbon and algal biomass. Black carbon comes from the incomplete combustion of biomass and fossil fuels. When the dark particles are deposited on snow and ice surfaces, the darker surface absorbs more solar radiation than the surrounding, lighter surface, reducing reflectance of solar energy and enhancing melt. The pigment of ice algae has a similar impact. Collecting these data will help scientists better understand the effects of ship traffic and long-range atmospheric transport that deposit black carbon on the sea ice.

The team left Nome, Alaska, on August 4, and is currently traveling eastwards between 74 and 75 degrees N and 167 degrees W. Before reaching the ice camp where the instruments will be deployed, the ship is retrieving and installing moorings. Ice conditions have been varied since the first sightings of sea ice occurred at 72 degrees 58 minutes N/168 degrees 18.2 minutes W. The first ice sighted mostly consisted of small multiyear ice remnants about 1 meter thick (3.3 feet) and less than 20 meters (66 feet) in size. Now the majority of the ice floes are thin, first-year ice floes between 50 to 200 meters (164 to 656 feet) in size, and 50 to 100 centimeters (1.6 to 3.3 feet) thick. While most of the ice is level ice, some large ridging has been observed. Almost all the ice floes have melt ponds, some discrete and some linked, especially on the thinner first-year ice. Most melt ponds have thaw holes. So far, the majority of melt ponds have a thin top ice layer as air temperatures are hovering around -3 degrees Celsius (27 degrees Fahrenheit). However, once the ship reached 179 degrees W, air temperatures approached 0 degrees Celsius (32 degrees Fahrenheit) and the melt ponds thawed. The most interesting feature thus far has been dirty ice in the midst of bright white ice (see Figure 4a). It is unclear if these dirty ice floes are a result of ice algae, dust, or soot deposits from this summer’s forest fires. The team has also been rewarded with sightings of polar bears (see Figure 4b).

Erratum

Readers alerted us to an error. On August 16, we reported the August 15 sea ice extent as 7.3 million square kilometers (2.82 million square miles) below the 1981 to 2010 average. Instead, it is 1.58 million square kilometers (610,000 square miles) below the 1981 to 2010 average. On August 17, 2018, we corrected the number.

Categories: Climate Science News

23 July - 5 August 2018 weeks

AVISO Climate Change News - Tue, 2018-08-07 02:14
2017, nouvelle année rouge pour le climat (Les Echos 02/08/2018) Climat : 2017, année de tous les records (Le Monde 01/08/2018) Les océans toujours aussi chauds, leur niveau toujours plus haut (BFM 02/08/2018) Seuls 13% des océans sont encore sauvages (Le Temps 26/07/2018) Environ 90% des manchots de cette colonie ont disparu, et personne ne sait pourquoi (sciencepost 31/07/2018) Un affaiblissement de la circulation océanique en Atlantique ne ralentirait pas le réchauffement climatique, mais conduirait à son amplification ! (sciencepost 28/07/2018) En plus de polluer les océans, le plastique contribue au réchauffement climatiquer ( Agence France-Presse, 02/08/2018) 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

Ice loss speeds up during second half of July

NSIDC Artic Sea Ice News - Thu, 2018-08-02 13:50

Arctic sea ice extent declined rapidly the latter half of July, despite the persistence of low sea level pressure over the Arctic Ocean and generally cool conditions. At the same time, unusually high sea level pressure persisted over the United Kingdom and Scandinavia, where several new record high temperatures were reached, fostering extensive wildfires.

Overview of conditions Figure 1. Arctic sea ice extent for July 2018 was 8.22 million square kilometers (3.2 million square miles). The magenta line shows the 1981 to 2010 average extent for that month.

Figure 1. Arctic sea ice extent for July 2018 was 8.22 million square kilometers (3.20 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 July 2018 averaged 8.22 million square kilometers (3.20 million square miles). This was 1.25 million square kilometers (483,000 square miles) below the 1981 to 2010 long-term average sea ice extent, and 550,000 square kilometers (212,000 square miles) above the record low for the month set in July 2012. July 2018 was the ninth lowest July extent in the satellite record.

Despite finishing ninth lowest in the monthly average, ice loss was rapid during the month. As a result, by July 31 daily extent tracked fourth lowest in the satellite record, just below the extent seen last year at this time, and also just above that seen in 2007, 2011, and 2012. Extent remained unusually low in the Atlantic sector of the Arctic, including the Barents, Kara, Laptev, and East Greenland Seas, whereas the ice edge in the Beaufort and East Siberian Seas remained near average. By the end of July, the ice within Hudson Bay had all melted out and the ice edge in the Chukchi Sea had also retreated far north of its average position for this time of year. This pattern is in stark contrast to last year when by July’s end, the ice edge was located far north of its usual position in the Beaufort and East Siberian Seas while with ice on the Atlantic side, extent was near average.

Conditions in context Figure 2. The graph above shows Arctic sea ice extent as of July 31, 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 2. The graph above shows Arctic sea ice extent as of July 31, 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

Total ice loss during July was 3.27 million square kilometers (1.26 million square miles), or a rate of -105,400 square kilometers (-41,000 square miles) per day. This was faster than the 1981 to 2010 long-term average rate of retreat for the month of -86,800 square kilometers (-34,000 square miles) per day. Ice retreat occurred primarily within Hudson Bay and the Kara, Laptev, and Chukchi Seas, and to a lesser extent within Baffin Bay, the East Greenland Sea and the East Siberian coastal regions. In contrast, ice expanded slightly in parts of the Beaufort Sea. While there was little overall change in ice extent in the Beaufort Sea, ice concentration remained low over much of the region, with large areas of open water developing between ice floes. Open water areas between floes readily absorb the sun’s energy and help to enhance lateral (from the side) and basal (from the bottom) melting. However, by the end of July the sun is lower in the sky as compared to June, so this effect is diminishing.

Continuing the pattern of the last two summers, low sea level pressure persisted over the central Arctic Ocean during July, a pattern that historically has tended to slow summer ice loss. Low sea level pressure also persisted over Greenland, paired with high sea level pressure over northern Europe and Siberia to the east, and high sea level pressure over Alaska and Canada to the west. This led to air temperatures at the 925 hPa level (approximately 2,500 feet above the surface) ranging from -0.5 to -4.0 degrees Celsius (-0.9 to -7.0 degrees Fahrenheit) below average over the Kara and Laptev, and from -0.5 to -2.0 degrees Celsius (-0.9 to -4.0 degrees Fahrenheit) over the Beaufort Sea. Near the pole, air temperatures were near average or slightly above average (+0.5 to +1.0 degrees Celsius or +0.9 to +2.0 degrees Fahrenheit). Air temperatures -0.5 to -3 degrees Celsius (-0.9 to +5.0 degrees Fahrenheit) below average also persisted over central and northern Greenland.

Meanwhile, over in Scandinavia several new record high temperatures were observed during the month. In Turku, Finland, temperatures soared to 33.3 degrees Celsius (91.9 degrees Fahrenheit) on July 17, the highest temperature recorded since 1914. In central Norway, the Trondheim airport reported a temperature of 32.4 degrees Celsius (90.3 degrees Fahrenheit) on July 16, the highest on record, while Bardufoss, just south of Tromsø within the Arctic circle, saw a new record of 33.5 degrees Celsius (92.3 degrees Fahrenheit) on July 18. In Sweden, more than forty forest fires raged across the country during the unprecedented heatwave in mid-July. Fires were also burning within Lapland and Latvia. However, it was not only Scandinavia experiencing hot and dry conditions. Western Europe continued to experience prolonged heatwaves. Wildfires in Greece have already killed nearly ninety people, while Japan declared their extreme heatwave as a natural disaster, as more than sixty-five people have died and 22,000 have been treated in hospitals.

July 2018 compared to previous years Figure 3. Monthly July ice extent for 1979 to 2018 shows a decline of 7.2 percent per decade.

Figure 3. Monthly July ice extent for 1979 to 2018 shows a decline of 7.2 percent per decade.

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

The linear rate of decline for July sea ice extent is 68,700 square kilometers per year (27,000 square miles per year) or 7.2 percent per decade relative to the 1981 to 2010 average.

Beaufort on the brink? Figure 4a. This shows a true color composite image of the Beaufort Sea in the Arctic, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the NASA Terra satellite.

Figure 4a. This shows a true color composite image of the Beaufort Sea in the Arctic, taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the NASA Terra satellite.

Credit: W. Meier, NSIDC/NASA
High-resolution image

Figure 4b. This image shows sea ice concentration in the Arctic, based on data from the Japan Aerospace Exploration Agency (JAXA) Advanced Microwave Scanning Radiometer 2 (AMSR2).

Figure 4b. This image shows sea ice concentration in the Arctic, based on data from the Japan Aerospace Exploration Agency (JAXA) Advanced Microwave Scanning Radiometer 2 (AMSR2).

Credit: University of Bremen
High-resolution image

Ice concentration over much of the Beaufort Sea has rapidly declined over the past couple of weeks. July 27 imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the NASA Terra satellite showed a large off-shore region with broken-up ice and small ice floes vulnerable to rapid melt by the surrounding ocean (Figure 4a). Sea ice concentration data provided by the University of Bremen from the higher resolution Japan Aerospace Exploration Agency (JAXA) Advance Microwave Scanning Radiometer 2 (AMSR2) showed an expanding open water area within the ice pack between mid-July and August 1 (Figure 4b). By August 1, substantial open water was found throughout the Beaufort. On the other hand, near the coast to the east of Utqiaġvik (formerly Barrow), more compact and likely thicker ice remains, which is less likely to rapidly melt away. How much of the Beaufort ice cover survives the summer and how much more melts away will depend considerably on the weather conditions over the next four to six weeks.

Melt onset a mixed bag Figure 5. These maps show preliminary melt onset (left) and melt onset anomaly (right) in the Arctic relative to the 1981 to 2010 average. White areas are open ocean or areas with no melt detected.

Figure 5. These maps show preliminary melt onset (left) and melt onset difference from average (right) in the Arctic relative to the 1981 to 2010 average. White areas are open ocean or areas with no melt detected.

Data courtesy Jeffrey Miller, NASA GSFC.
High-resolution image

This summer the ice retreated quite early in the Bering Sea in late April and early May, leading to record low extent in the region. This is partly because the melt started nearly two months earlier than average in certain parts of the Bering Sea, while the regional average melt onset date was 38 days earlier. Melt also began several weeks earlier than average in the Barents Sea, stretching up through the Kara Sea and the southern Laptev Sea. In contrast, melt was later than average in most of the Chukchi and East Siberian Seas as well as parts of the Beaufort Sea. While melt onset generally happens earlier in the southern parts of the Arctic and later as one moves further north, exceptions do occur. For example, already in March some melt onset was detected over the central Arctic Ocean, but it did not continuously melt since that date.

Reconstructing sea ice extent in the Kara and Barents Seas Figure 6. This graph shows reconstructions of sea ice extent in the Barents and Kara Seas from 1289 to 1993 (red line). The gray line shows the 30-year average, the blue line shows observed sea ice extent, and the green line shows the trend.

Figure 6. This graph shows reconstructions of sea ice extent in the Kara and Barents Seas from 1289 to 1993 (red line). The gray line shows the 30-year average, the blue line shows observed sea ice extent, and the green line shows the trend.

Credit: Qi Zhang (Institute of Polar Meteorology, Chinese Academy of Meteorological Sciences, Bejing, China) and Cunde Xiao (Stake Key Laboratory of Earth Surface and Resources Ecology, Beijing Normal University, Bejing, China)
High-resolution image

While we now have forty years of consistent sea ice observations from satellite, this data record is still relatively short, especially for trying to better understand drivers of current sea ice loss and issues such as potential impacts on mid-latitude weather. A new study from a team of Chinese researchers relied on climate proxies from ice cores and tree ring data from coastal forests to provide estimates of autumn sea ice within the Kara and Barents Seas back to 1289. This new data record suggests that between the 13th and 18th centuries, sea ice extent in the Kara and Barents Seas was more extensive than today and was increasing slightly. This period coincides with the Little Ice Age. After the end of the 18th century, sea ice in this region began to decline and the downward trend became significant during the second half of the 19th century until about the 1930s to 1940s. The sea ice then expanded until the 1970s, after which it has continually declined. Based on this reconstruction, current ice loss in the Kara and Barents Seas is viewed as unprecedented, both in duration and rate of change. While the study is only regional and does not indicate overall Arctic-wide sea ice changes, it provides useful context for the recent decline relative to the long-term variability.

Antarctic sea ice update

Sea ice in the Southern Hemisphere grew at a slightly faster-than-average pace from June through mid-July, but then slowed through the second half of July. At mid-July, ice extent was near average in all sectors except the region north of Dronning Maud Land. In the last two weeks of July, an area of below-average ice extent developed north of Wilkes Land in response to warm winds from the northeast, reducing the overall ice growth and bringing the Southern Hemisphere ice extent down relative to the 1981 to 2010 average (below the range of 90 percent of the past observational years). Above average temperatures at the 925 hPa level (about 2,500 feet above sea level) of 4 to 5 degrees Celsius (7 to 9 degrees Fahrenheit) occurred over the northern West Antarctic coast and the southern Peninsula, where the Peninsula high pressure ridge brought winds from the north. Temperatures 3 to 6 degrees Celsius (5 to 11 degrees Fahrenheit) above average also occurred along the Wilkes Land coast.

References

Divine, D. V. and C. Dick. 2007. March through August ice edge positions in the Nordic Seas, 1750-2002, Version 1. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: https://doi.org/10.7265/N59884X1.

Zhang, Q., C. Xiao, M. Ding, and T. Dou. 2018. Reconstruction of autumn sea ice extent changes since AD1289 in the Barents-Kara Sea, Arctic. Science China Earth Sciences, doi:10.1007.s11430-017-9196.4.

Categories: Climate Science News

August 2018: Waves steepen in accelerating currents

AVISO Climate Change News - Wed, 2018-08-01 01:08
Altimetry showns an increased steepness of waves interacting with currents accelerating abruptly....
Categories: Climate Science News

Visual presentation of the ODATIS Ocean Cluster

AVISO Climate Change News - Mon, 2018-07-30 02:41
ODATIS, Ocean Data Information and Services, serves as the entry point to access all French Ocean observation data. Its general objective is to promote and facilitate the use of ocean observations sampled by way of in situ and remote sensing measurements. ODATIS contributes to describing, quantifying and understanding the ocean as a whole — offshore and coastal — with regard to aspects such as the dynamics and thermodynamics of the ocean, the evolution of its physico-chemical properties, biogeochemical cycles, the operation of marine ecosystems, the evolution of the ocean and the ocean-climate relationship in the past. See the video presentation on the ODATIS website (in french)
Categories: Climate Science News

[JASON-2] : BACK TO OPERATIONS

AVISO Climate Change News - Wed, 2018-07-25 08:27
From today at 08:30UTC Jason-2 spacecraft is back to operations. The first OGDRs could be generated around 10:45UTC.  It is now starting its measurements on the i-LRO orbit, on cycle 600.
Categories: Climate Science News

9 - 22 July 2018 weeks

AVISO Climate Change News - Mon, 2018-07-23 03:24
Why Our Intuition About Sea-Level Rise Is Wrong (Nautilus, 19/07/2018) Expected sea-level rise following Antarctic ice shelves' collapse (Science Daily, 19/07/2018) Reducing carbon emissions could limit sea level rise (Knowridge, 18/07/2018) The Water is Wider (Earth Observatory, 18/07/2018) Giant Iceberg Looming Over Greenland Village Is the Perfect Metaphor for 2018 (Earther, 18/07/2018) Reducing carbon emissions will limit sea level rise (Science Daily, 16/07/2018) Buried internet infrastructure at risk as sea levels rise (Science Daily, 16/07/2018) Geological records reveal sea-level rise threatens UK salt marshes, study says (Science Daily, 12/07/2018) The 'monster' iceberg: What happened next? (BBC news, 09/07/2018) La préservation des mers et des océans inscrite dans la Loi (Sciences et Avenir, 20/07/2018) Le réchauffement climatique peut-il favoriser les conflits armés ? (Sciences et Avenir, 15/07/2018) Les satellites du CNES aident les sinistrés au Japon (La Dépêche, 14/07/2018) Réchauffement climatique : il faut peut-être s’attendre à pire (Science Presse, 11/07/2018) Le programme spatial européen Copernicus, une ambition citoyenne, un leadership économique (La Tribune, 10/07/2018) La bataille de l’Arctique a bel et bien commencé (Courrier International, 09/07/2018) 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

[JASON-2] : SATELLITE IN SAFE HOLD MODE SINCE WEDNESDAY JULY 18th 09:00 UTC

AVISO Climate Change News - Wed, 2018-07-18 07:50
The Jason-2 spacecraft entered safe mode today (Wednesday, July 18th) at 09:00UTC, immediately interrupting its measurements.   The satellite is currently in a safe and stable Sun-pointing configuration. The analysis of the telemetry shows that the safe hold mode is consecutive to a gyro #1 disjunction. Those anomalies are now known and, as decided during last JSG, the reconfiguration of the satellite on gyro#2 started immediately. Recovery operations will keep on during the following days, and Jason-2 mission is expected to restart nominally next week, hopefully on Wednesday, July 25th. The exact time of instruments restart will be communicated later.  

As indicated earlier this week, Jason-2 maneuvers have been performed in order to place Jason-2 on an “interleaved LRO” orbit, so that more precise results are available for geodetic purpose. Fortunately, the reconfiguration to safe hold mode has been triggered after the last maneuver, which means Jason-2 should be ready to provide measurements on cycle 600 (new cycle numbering for the i-LRO measurements) right after restart.
Categories: Climate Science News

Smoke on the frozen water

NSIDC Artic Sea Ice News - Tue, 2018-07-17 11:00

Sea ice declined at a near average rate through the first half of July as low sea level pressure dominated the Arctic Ocean. Wind patterns caused smoke from Siberian forest fires to sweep over the ice.

Overview of conditions Figure 1. Arctic sea ice extent for July 15, 2018 was 3.3 million square kilometers (3.8 million square miles). The orange line shows the 1981 to 2010 average extent for that day.

Figure 1. Arctic sea ice extent for July 15, 2018 was 8.5 million square kilometers (3.3 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

As of July 15, Arctic sea ice extent was 8.5 million square kilometers (3.3 million square miles). This is 1.24 million square kilometers (479,000 square miles) below the 1981 to 2010 average, but 670,000 square kilometers (259,000 square miles) above the record low for this day in 2011. While total Arctic sea ice extent was tracking at record low levels during winter, the rate of summer ice loss has been unremarkable thus far. Thus far in July, ice retreat has been most pronounced in the Kara Sea, whereas in the Beaufort Sea, the ice edge expanded slightly southwards. The ice edge has changed little within the Barents and East Greenland Seas on the Atlantic side, and retreat has been sluggish in the Chukchi Sea on the Pacific side of the Arctic Ocean.

Conditions in context Figure 2. The graph above shows Arctic sea ice extent as of July 15 , 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, 2015 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 July 15, 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 average sea level pressure in the Arctic, in millibars, for July 1 to 15, 2018. Yellows and reds indicate higher than average sea level pressure; blues and purples indicate lower than average sea level pressure.

Figure 2b. This plot shows average sea level pressure in the Arctic, in millibars, for July 1 to 15, 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

Through the first two weeks of July, ice extent declined at a rate of 134,000 square kilometers (52,000 square miles) per day, which is near the 1981 to 2010 average. The spatial pattern of ice loss has not changed much since the end of June, with minimal ice loss around the entire ice edge. The Beaufort Sea saw some increase in extent due to the transport of ice from the north. Low sea level pressure dominated the central Arctic Ocean and Greenland. Typically, this pattern, associated with counterclockwise (cyclonic) winds is associated with cool conditions and also causes ice divergence, helping to spread the ice cover over a larger area. However, air temperatures over the pole and the East Siberian and Chukchi Seas at the 925 hPa level (approximately 2,500 feet above the surface) ranged 1 to 2 degrees Celsius (2 to 4 degrees Fahrenheit) above average for the first part of July. Regions with below average air temperatures were found in the Kara, Laptev, and Beaufort Seas (-1 to -3 degrees Celsius or -2 to -5 degrees Fahrenheit below average).

The passive microwave data show a decrease in ice concentration in several areas of the Arctic Ocean, particularly in northern areas of the Beaufort and Chukchi Seas. This is not necessarily a real decrease—it manifests as surface melt and the development of melt ponds on the ice surface. Microwave emission is sensitive to the freeze-thaw state of water. Liquid water atop the ice surface changes the returned signal, mimicking a reduced sea ice concentration. Because the calculation of ice extent does not consider concentration (except for the 15 percent concentration threshold), extent values are much less sensitive to this melt effect. During the melt season, ice extent provides a more consistent and reliable measure of total ice cover.

Siberian smoke over the Arctic Ocean  NASA| High-resolution image

Figure 3. These images from the NASA Moderate Resolution Imaging Spectroradiometer (MODIS) sensor show the Arctic Ocean and surrounding land from July 3 to 6, 2018. Blue arrows indicate smoke that had drifted from fires in Siberia.

Credit: NASA
High-resolution image

Fires in the western United States have been much in the news lately. Less noted are significant fires in Siberia. Over several days at the beginning of July, smoke from these fires was brought into the Arctic Ocean by winds associated with the pattern of low pressure in the region. The smoke streamed over the East Siberian, Chukchi, and Beaufort Seas and eventually across Alaska into northern Canada.

The smoke has two potential effects on sea ice. First, as it drifts over the ice, the smoke particles scatter solar radiation and reduce how much is received at the surface. This has a cooling effect that will tend to reduce the rate of ice loss. However, smoke particles that settle onto the ice will darken the surface, thus decreasing the reflectivity of the surface, or albedo. This increases the amount of solar energy absorbed by the ice and enhances melt. The atmospheric scattering effect of the smoke is short term and dissipates after the smoke drifts away. The surface albedo effect has a longer-term impact and could serve to enhance melt rates through the summer. The magnitude of the effect will depend on how many smoke particles are deposited on the surface, the albedo of the surface that the particles fall on, and the amount of cloud cover which reduces the incoming sunlight. The biggest effect would be on bright, snow-covered ice. It would be smaller on darker melting ice and melt ponds, and there would be no effect in open water areas.

 

 

 

Categories: Climate Science News

2 - 8 July week

AVISO Climate Change News - Thu, 2018-07-12 08:02
Baltic Sea oxygen levels at '1,500-year low due to human activity' (The Guardian, 05/07/2018) Red-hot planet: All-time heat records have been set all over the world during the past week (The Washington Post, 05/07/2018) Démarrage officiel de l’Observatoire spatial du climat (Air&Cosmos, 05/07/2018) Great Barrier Reef Imperiled as Heat Worsens Die-Offs, Experts Say (The New York Times, 04/07/2018) Les cyclones tropicaux sont plus lents, et donc potentiellement plus destructeurs (Pour la Science, 04/07/2018) Rising sea levels could cost the world $14 trillion a year by 2100 (Science Daily, 03/07/2018) Gulf stream eddies as a source of iron (Science Daily, 03/07/2018) Le dérèglement du Jet Stream multiplie les canicules dans le monde (Up' magazine, 02/07/2018) 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

July 2018: Adopting a Swot crossover for biophysical studies

AVISO Climate Change News - Fri, 2018-07-06 03:13
Swot will be a major asset to study the socean fine scales, especially relevant for marine biology....
Categories: Climate Science News

July 2018: Adopting a Swot crossover for biophysical studies

AVISO Climate Change News - Fri, 2018-07-06 03:13
Swot will be a major asset to study the socean fine scales, especially relevant for marine biology....
Categories: Climate Science News

A sluggish June

NSIDC Artic Sea Ice News - Wed, 2018-07-04 11:44

Arctic sea ice extent declined at a slightly slower-than average pace in June. Despite the slow loss, warm conditions and winds from the south developed a large area of open water in the Laptev Sea.

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

Figure 1. Arctic sea ice extent for June 2018 was 10.7 million square kilometers (4.1 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 June 2018 averaged 10.7 million square kilometers (4.1 million square miles). This was 1.05 million square kilometers (405,000 square miles) below the 1981 to 2010 average and 360,000 square kilometers (139,000 square miles) above the record low June extent set in 2016. This was the fourth lowest June average extent in the satellite record.

Extent at the end of June remained below average in the Chukchi Sea, but because of slow retreat through June in the region, extent in the Chukchi is now closer to average than was the case at the end of May. The Barents Sea and East Siberian Sea also have extents well below average at the end of June. Most of the ice in the Sea of Okhotsk has melted. Ice has been retreating in the west side of Hudson Bay where extent is below average. However, this is countered by above average extent in the eastern side of the bay. Notably, a large area of open water has developed in the Laptev Sea, leading to record low extents in that region during the first half of June.

Conditions in context

Figure 2. The graph above shows Arctic sea ice extent as of July, 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

Figure 3

Figure 3a. This plot shows the average sea level pressure in the Arctic at the 925 hPa level, in millibars, for June 2018. Yellows and reds indicate higher than average air pressure; blues and purples indicate lower than average air pressure.

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

Figure 3b

Figure 3b. 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.

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

The salient features of the atmospheric pattern for June include a region of low sea level pressure centered over the northern Barents Sea, and a high pressure cell centered over the Laptev Sea. A ridge of high pressure also extends eastward into northern Canada (Figure 3a). Winds from the south between the low pressure area in the Barents Sea and the high pressure area in the Laptev Sea gave rise to a pronounced region of above-average temperatures centered over Central Siberia and extending over the Laptev and East Siberian Seas (Figure 3b). However, elsewhere over the Arctic Ocean, temperatures were near average or slightly below average.

The temperature pattern is consistent with the early development of open water in the Laptev Sea. Extents in this area oscillated between slightly above and below the record low extent set in June 2014. Parts of the Laptev Sea opened as early as mid-April, likely due to winds transporting ice away from the fast ice zone (ice that is locked to the shoreline). While new ice formed in these open water areas, this ice was thin and prone to melting out once the summer melt season started.

Also of note was the passage of a strong cyclone in early June. This system moved into the Kara Sea on June 6, and reached a minimum central pressure of less than 970 hPa on June 7. By June 10, it had migrated into the Beaufort Sea. It dissipated on June 13.

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

Figure 4. Monthly June ice extent for 1979 to 2018 shows a decline of 4.1 percent per decade.

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

The linear rate of decline for June sea ice extent is 48,000 square kilometers (18,500 square miles) per year, or 4.1 percent per decade relative to the 1981 to 2010 average. Ice loss during the month was 1.6 million square kilometers (618,000 square miles), somewhat slower than the 1981 to 2010 average loss of 1.7 million square kilometers (656,000 square miles) for the month. Clearly the early ice losses in the Laptev Sea, associated with warm conditions over the region, could not make up for slower retreats elsewhere.

New insights into warming in the northern Barents Sea

An interesting feature of recent years is a region of unusually high winter air temperatures, or a winter hotspot, over the northern Barents Sea. Previous studies have provided evidence linking the hotspot to a halocline retreat, which is a retreat or weakening of the cold, fresh waters at the ocean surface that prevent ocean heat imported from the Atlantic from mixing upwards. A new paper by Lind et al. (2018) argues that the hotspot is driven by the lack of sea ice transport. Sea ice is mostly fresh water (low salinity) and less is being transported into that region. Hence the ocean surface becomes less fresh over the northern Barents Sea, allowing the warm Atlantic water to mix upwards.

Antarctica in June Figure 5

Figure 5. This plot shows departure from average air temperature in Antarctica 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.

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

Sea ice expanded at a faster-than-average pace in June in the Southern Hemisphere, bringing Antarctic sea ice extent closer to typical ice extents for this time of year. This follows on the heels of a period of below-average ice extent since austral winter in 2016. Sea ice extent is near average in all sectors except the northeastern Weddell Sea, and a small area in the northern Davis Sea. Higher-than-average air temperatures prevailed in these regions, and cool conditions prevailed over the northern Ross Sea.

Antarctica’s sea ice and ice shelf disintegration

A new study in the Journal Nature found that reduced sea ice in the northwestern Weddell Sea and southern Bellingshausen Sea likely contributed to the weakening of major ice shelves prior to their disintegration in the 1990s and early 2000s. Loss of the sea ice buffer near Antarctica’s coast allows long-period ocean swell to flex ice shelves. Under ordinary conditions, this flexing has little effect. However, if the ice shelves have been pre-conditioned by seasonal melt-water flooding, the flexing by wave action in late summer can have a devastating effect. Minor flexure of the ice shelf plate allows water to infiltrate existing cracks and initiate fracturing of the ice.

Four major ice shelf break-up events in 1995 (Larsen A), 2002 (Larsen B), and 2008 and 2009 (Wilkins) all occurred after multiple weeks where no sea ice was present near the ice shelf fronts to dampen ocean swell. In the case of the Larsen A and B events, the loss of the ice shelves initiated a significant acceleration of the tributary glaciers. The study demonstrates that sea ice—a component of the cryosphere that is very sensitive to changing climate and ocean—has an important protective effect on the Antarctic ice sheet.

Further Reading

Lind, S., R. B. Ingvaldsen, and T. Furevik. 2018. Arctic warming hotspot in the Northern Barents Sea linked to declining sea-ice import. Nature Climate Changedoi:10.1038/s41558-018-0205-y.

Massom, R., T. A. Scambos, L. G. Benetts, P. Reid, V. A. Squire, and S. Stammerjohn. 2018. Antarctic ice shelf disintegration triggered by sea ice loss and ocean swell. Nature, 558, 383-389, doi:10.1038/s41586-018-0212-1.

Categories: Climate Science News

25 June - 1 July 2018 week

AVISO Climate Change News - Tue, 2018-07-03 01:41
Comment les satellites Jason ont révolutionné notre connaissance du climat (Futura Sciences, 30/06/2018) Politique américaine des océans : exit le climat (Science Presse, 29/06/2018) The Sounds of Satellites (Earth Observatory, 28/06/2018) Global surface area of rivers and streams is 45 percent higher than previously thought (Science Daily, 28/06/2018) Un œil sur l’océan (Télématin Sciences, 27/06/2018) Images satellitaires et drones, de nouveaux alliés contre le réchauffement climatique (Le Monde, 26/06/2018) L’Europe met à disposition toutes ses données climatiques. On ne pourra pas dire qu’on ne savait pas… (Up' magazine, 26/06/2018) 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

New SSALTO/DUACS Experimental products delivery

AVISO Climate Change News - Fri, 2018-06-29 06:02
We are proud to announce the release of the new AVISO+ SSALTO/DUACS experimental products. For 20...
Categories: Climate Science News

Feeling the heat

NASA Climate News - Fri, 2012-09-14 00:09
A former intern tells why she?s returned to JPL
Categories: Climate Science News

Grace mission offers a novel view of Earth?s water supplies

NASA Climate News - Thu, 2012-09-13 02:09
The Grace mission offers a novel and much needed view of Earth?s water supplies.
Categories: Climate Science News

'Earth Now' available for Android

NASA Climate News - Mon, 2012-09-10 02:09
Follow the vital signs of our planet
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NASA's Global Hawk mission begins with flight to Hurricane Leslie

NASA Climate News - Fri, 2012-09-07 01:09
NASA has begun its latest hurricane science field campaign.
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NASA voyage set to explore link between sea saltiness and climate

NASA Climate News - Tue, 2012-09-04 22:09
A NASA-sponsored expedition is set to sail to the North Atlantic's saltiest spot.
Categories: Climate Science News
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