Climate Science News

[Jason-2/Jason-3] MOE calculation takes into account DORIS and GPSP measurements

AVISO Climate Change News - Thu, 2019-02-14 03:27
No change should be seen in the products, except an improvement of MOE precision. Please note that in case of temporary unavailability of GPSP measurements, the calculation will automatically be performed using the former way of calculations, i.e. only with DORIS measurements.
Categories: Climate Science News

Polar vortex breakdown

NSIDC Artic Sea Ice News - Tue, 2019-02-05 11:30

In January 2019, a pattern of high-altitude winds in the Arctic, better known as the polar vortex, weakened, sweeping frigid air over North America and Europe in the second half of the month. Arctic sea ice extent remained well below average, but temperatures in the far north were closer to average than in past years.

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

Figure 1. Arctic sea ice extent for January 2019 was 13.56 million square kilometers (5.24 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 January averaged 13.56 million square kilometers (5.24 million square miles). This was 860,000 square kilometers (332,000 square miles) below the 1981 to 2010 long-term average sea ice extent, and 500,000 square kilometers (193,000 square miles) above the record low for the month set in January 2018. January 2019 was the sixth lowest January extent in the 1979 to 2019 satellite record.

The average rate of daily ice growth of 51,200 square kilometers (19,800 square miles) was faster than the long-term average. Ice growth primarily occurred in the Bering Sea and Sea of Okhotsk in the Pacific sector as well as in the Labrador and Kara Seas. Some ice spread to the northeast of Svalbard, while retreating slightly to the northwest of these islands. Total ice extent was tracking at eighth lowest on January 31, with below average extent in nearly all sectors of the Arctic.

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

Figure 2a. The graph above shows Arctic sea ice extent as of February 5, 2019, along with daily ice extent data for four previous years and the record low year. 2018 to 2019 is shown in blue, 2017 to 2018 in green, 2016 to 2017 in orange, 2015 to 2016 in brown, 2014 to 2015 in purple, and 2012 to 2013 in dotted brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

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

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

Figure 2b. This plot shows the departure from average air temperature in the Arctic at the 925 hPa level, in degrees Celsius, for January 2019. 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 departure from average sea level pressure in the Arctic at the 925 hPa level, in degrees Celsius, for January 2019. 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

Arctic temperatures were only slightly above average, contrasting recent Januaries when very warm conditions prevailed. Daily 2 meter air temperatures for the Arctic averaged above 80 degrees North from the Danish Meteorological Institute were just a few degrees above the 1958 to 2002 average, whereas in 2018, temperatures ranged from 4 to 12 degrees Celsius (7 to 22 degrees Fahrenheit) above average. Looking at the 925 hPa level (approximately 2,500 feet above the surface; Figure 2b), temperatures of 1 to 2.5 degrees Celsius (2 to 4.5 degrees Fahrenheit) above the 1981 to 2010 average were the rule over the Beaufort Sea and Canadian Arctic Archipelago, and over the Bering Sea. However, part of the Atlantic side of the Arctic had temperatures near or slightly below average for the month. The atmospheric circulation pattern was unusual, with above average pressure at sea level over a broad area including northern Canada, Greenland, and the northern North Atlantic, and a broad area of below average pressure along the Russian and Siberian Arctic coast. Low pressure also prevailed over the northern Pacific and Bering Sea (Figure 2c).

January 2019 compared to previous years  National Snow and Ice Data Center| High-resolution image

Figure 3. Monthly January ice extent for 1979 to 2019 shows a decline of 3.2 percent per decade.

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

Overall, sea ice extent during January 2019 increased by 1.59 million square kilometers (614,000 square miles). This was 270,000 square kilometers (104,000 square miles) above the 1981 to 2010 average rate for the month. The linear rate of sea ice decline for January was 46,700 square kilometers (18,000 square miles) per year, or 3.2 percent per decade relative to the 1981 to 2010 average.

Cold shoulder At left, upper atmosphere winds (70 millibars, about 60,000 feet altitude) on 15 January 2019. North America is in the center of this view. Right, surface air temperatures on 30 January, 2019. For reference, Chicago was -26 C (-15°F) on this morning (dark blue color)

Figure 4. The left image shows atmosphere winds (70 millibars, about 60,000 feet altitude) on January 15, 2019. North America is in the center of this view. The right image shows surface air temperatures on January 30, 2019. For reference, Chicago was -26 degrees Celsius (-15 degrees Fahrenheit) on this morning (dark blue color)

Credit: earth.nullschool.net
High-resolution image

When well developed, the upper atmosphere circumpolar wind pattern, or polar vortex, isolates cold Arctic air in the far north, strengthens the mid-latitude jet stream, and reduces the frequency of frigid air outbreaks into lower latitudes. Early in January 2019, the polar vortex split into several separate closed streams. There was an outbreak of bitter cold air crossing southern Canada, the US Midwest, and the East Coast, during the last week of January. Such events have been popularly termed “invasions of the polar vortex.”

Conditions in the upper US Midwest were colder than any previous winter period in the past two decades. Low temperatures in northern Minnesota and all of Wisconsin on January 30 and 31 were in the -27 to -35 degrees Celsius range (-17 to -31 degrees Fahrenheit). Large areas of Michigan, Ohio, Indiana, Iowa, and the Dakotas reached temperatures below -20 degrees Celsius (-4 degrees Fahrenheit). However, few all-time low temperature records were set during the cold snap. Very mild conditions followed the cold snap in early February.

Arctic change: Fast and furious…and urgent

In a recent review paper (Overland et al., 2019), colleagues from a spectrum of polar geophysics disciplines summarized the many facets of the Arctic’s ongoing transformation, noting that this region, perhaps foremost in the globe, requires a quick adjustment to the pace of climate change. The amplification of global climate change in the Arctic, and the emerging potential for long-term atmospheric and ocean circulation changes, permafrost greenhouse gas release, and the effects of changing snow cover and snowmelt timing, point to serious but hard-to-forecast impacts on global society and infrastructure by the second half of this century.

Antarctic notes

After a rapid December loss and record low extent in early January, Antarctic sea ice extent declined at a slower-than-average rate. On January 31, Antarctic sea ice extent dropped to third lowest on record, tying with 2006 and bested by 2017 and 2018. Sea ice extent was particularly low in the eastern Weddell Sea and the eastern Ross Sea. Over the satellite record, Antarctic January sea ice was increasing at 4,400 square kilometers (1,700 square miles) per year or 0.9 percent per decade, although this was not statistically significant at the 95 percent confidence level. The Antarctic minimum for the year is typically in late February. The Southern Annular Mode, similar to the polar vortex for the southern hemisphere, was in its positive phase, favoring westerly winds around the continent and cool conditions over its ice sheet. This was indeed the case for East Antarctica, where temperatures were 2 to 6 degrees Celsius (4 to 11 degrees Fahrenheit) below the 1981 to 2010 mean, but other parts of Antarctica and the surrounding sea ice areas were near average.

References

Danish Meteorological Institute Arctic temperatures

Overland, J., E. Dunlea, J. Box, R. Corell, M. Forsinus, V. Kattsov, M. S. Olsen, J. Pawlak, L-O Reirson, and M. Wang. 2019. The urgency of arctic change. Polar Science. doi:10.1016/j.polar.2018.11.008

 

 

Categories: Climate Science News

February 2019: Sharks in eddies and meanders

AVISO Climate Change News - Fri, 2019-02-01 03:08
Using the physical parameters of the environment, in particular from altimetry satellites, coupled...
Categories: Climate Science News

[Sentinel-3B L2P] redelivery of L2P S3B Near Real Time and Short Time Critical

AVISO Climate Change News - Tue, 2019-01-29 08:43
Please be informed that some global attribute values ("platform", "title", "summary", "source") were not appropriate in the Sentinel-3B L2P NRT and STC files delivered on the Aviso+ ftp server since the 2019/01/24.  The other attributes and variables as well as the scientific values were not affected. As a result, the whole files of the time series have been reprocessed and redistributed today (29/01 after 14h UTC) on the Aviso+ ftp server. We apologize for the inconvenience this has caused.
Categories: Climate Science News

08 - 24 January 2019 Press review

AVISO Climate Change News - Tue, 2019-01-29 01:07
EU and ESA signs agreement to provide financial resources for Copernicus Programme (Geospatial World, 24/01/2019) Deep data state of the climate: How the world warmed in 2018 (Red Green and Blue, 22/01/2019) How Arctic Cyclones Change the Sea Ice (EOS, 14/01/2019) Climate change makes seas rise faster and faster (Science News for Students, 10/01/2019) Three pioneers in the study of rising sea levels win the Frontiers of Knowledge Award (EurekAlert!, 09/01/2019) How Much Hotter Is Your Hometown Than When You Were Born? (The New York Times) Le réchauffement de l’océan conduit à des vagues de plus en plus puissantes (Science Post, 22/01/2019) Espace : à quoi vont servir cette année les 5,72 milliards d'euros de budget de l'ESA ? (Futura Sciences, 22/01/2019) Russie : Un nouveau satellite pour observer les phénomènes climatiques dans la zone de l'Arctique (Le Matin, 20/01/2019) Copernicus lance une nouvelle base de données pour l'observation du climat mondial (Environnement Magazine, 18/01/2019) The Ocean Cleanup : le système de nettoyage en mer imaginé par Boyan Slat en réparation à Hawaï (La 1ère France TV Info, 16/01/2019) L’océan Pacifique est en train de se refroidir en profondeur (Futura Sciences, 08/01/2019) 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

[Sentinel-3B] New added-value products are available

AVISO Climate Change News - Thu, 2019-01-24 06:46
We are pleased to inform you that the Along-track Sea Surface Heights Level-2+ (L2P) products are now available for Sentinel-3B. These mono-mission products contain along-track corrected sea surface heights with respect to a mean sea surface, corrections and geophysical parameters. The last versions of altimetric standards are used and there is a homogenized format for all satellites. These new products are processed by the Sentinel-3 L2P/L3 Marine Altimetry Service (CNES/CLS), in the frame of a EUMETSAT contract, part of the COPERNICUS Programme funded by the European Union.  The products are available in Near-Real Time, Short Time Critical and Non Time Critical, and the service is operational.  Dissemination: Sentinel-3B L2P are disseminated by AVISO+ (via ftp or AVISO+ CNES Data Center) and NRT/STC products will also be disseminated in the near future by EUMETSAT via EUMETCast. AVISO+ access: For new users, please see information and registration on the product page. For AVISO+ registered users, 
  • if you are already registered to Along-track Sentinel-3A L2P products, the new mission is available with the same access (just replace s3a by s3b)
  • if not, you need to choose the product "Sea Level Anomalies Along-track Level-2+ (L2P) Sentinel-3” in your private space. 
Categories: Climate Science News

How to use altimetry for hydrology?

AVISO Climate Change News - Mon, 2019-01-21 00:26
 This document, in pdf, have been written thanks to the help of many people. It explains the details and technical points of altimetry for hydrology. Available now in English and French, soon in Spanish and Portuguese. 
Categories: Climate Science News

Jason-3's third birthday

AVISO Climate Change News - Fri, 2019-01-18 10:01
After three years in orbit, Jason-3 closes its routine operations phase. But its mission has been extended for at least two more years. This "extended routine operations phase" will thus ensure the continuation of the high-precision sea-level measurement that began more than 25 years ago.  Jason-3 will play a key role in the commissioning of its successor Jason-CS / Sentinel-6A, which is scheduled for launch in November 2020. It will allow the in flight cross-calibration of the instruments .  See CNES's press release to know more about Jason-3's story.
Categories: Climate Science News

Presentation of Swot future data products for hydrology and oceanography

AVISO Climate Change News - Thu, 2019-01-17 07:30
Information on what the future Swot products will be in terms of content, format, etc.
Categories: Climate Science News

17 December - 07 January 2019 Press review

AVISO Climate Change News - Fri, 2019-01-11 09:26
How El Nino Impacts Solar and Wind Power Supply (WeatherNation, 07/01/2019) Study finds 2018 was fourth warmest on record: EU's Copernicus (Euronews, 07/01/2019) Scientists Invited to Collaborate in Satellite Mission’s Debut (Eos, 02/01/2019) Vital ecosystems in tidal flats lost to development and rising sea levels (The Guardian, 28/12/2018) Deadly weather: the human cost of 2018's climate disasters – visual guide (The Guardian, 21/12/2018) Interpreting Mosaics of Ocean Biogeochemistry (Eos, 17/12/2018) Sentinel satellites study climate-threatened Camargue (Euronews, 14/12/2018) L’année 2018 est la plus chaude jamais enregistrée en France (Le Monde, 21/12/2019) Pourquoi manque-t-on de plus en plus d'eau alors que les pluies augmentent ? (Futura Planète, 20/12/2018) 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] has restarted successfully on Monday 7th, January

AVISO Climate Change News - Fri, 2019-01-11 07:52
Jason-2 is then back to nominal activities at cycle 617, pass 132.
Categories: Climate Science News

New year lows once again

NSIDC Artic Sea Ice News - Mon, 2019-01-07 12:20

As 2018 came to a close, Arctic sea ice extent was tracking at its third lowest level in the satellite record, while sea ice in the Antarctic remained at historic lows. Slightly faster growth in the first few days of the new year, mostly in the Pacific sea ice areas, has the daily sea ice extent at fifth lowest as of this post.

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

Figure 1. Arctic sea ice extent for December, 2018 was 11.86 million square kilometers (4.60 million square miles). The magenta 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

Arctic sea ice extent for December averaged 11.86 million square kilometers (4.60 million square miles). This was the fourth lowest December average in the 1979 to 2018 satellite record, falling 980,000 square kilometers (378,000 square miles) below the 1981 to 2010 average, and 400,000 square kilometers (154,000 square miles) above the record December low set in 2016. However, slow ice growth during the second half of the month resulted in an ice extent that was tracking third lowest for December 31. Since then, growth has sped up, especially within the Sea of Okhotsk and to a lesser degree in the southwestern Kara Sea, bringing the daily sea ice extent up to the fifth lowest in the satellite record.

As has been typical the last few winters, sea ice extent remained below average within the Kara and Barents Seas, tracking third lowest in the Barents Sea as of December 31 and second lowest for the month of December as a whole. December extent in the Kara Sea was the fifth lowest for the month. Much of the area around Svalbard remains ice free. Elsewhere, ice extent tracked near average for this time of year, including in the Chukchi Sea where the ice was slow to form this past winter.

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

Figure 2a. The graph above shows Arctic sea ice extent as of January 7, 2018, along with daily ice extent data for four previous years and the record low year. 2018 to 2019 is shown in blue, 2017 to 2018 in green, 2016 to 2017 in orange, 2015 to 2016 in brown, 2014 to 2015 in purple, and 2012 to 2013 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. About the data

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

Figure 2. Daily 2m air temperatures for the Arctic averaged above 80oN from Zachary Labe, using ERA40 for the 1958-2002 climatology (blue line) and the operational ECMWF for the current year (in red). Figure is modified from the Danish Meteorological Institute.

Figure 2b. This graph shows daily air temperatures at 2 meters for the Arctic averaged above 80 degrees North from Zachary Labe, using ERA40 for the 1958 to 2002 climatology (blue line) and the operational European Centre for Medium-Range Weather Forecasts (ECMWF) for the current year (in red).

Figure is modified from the Danish Meteorological Institute
High-resolution image

Unfortunately, as a result of the partial government shutdown, we are unable to access the National Oceanic and Atmospheric Administration (NOAA) pages to retrieve information on atmospheric air temperatures and sea level pressure patterns. Instead, we turn to daily (2 meters above the surface) mean air temperatures north of 80 degrees North from the European Centre for Medium-Range Weather Forecasts (ECMWF) operational model. This analysis shows that air temperatures remained above the 1958 to 2002 average for all of December (Figure 2b).

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

Figure 3. Monthly December ice extent for 1979 to 2018 shows a decline of 3.7 percent per decade.

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

Overall, sea ice extent during December 2018 increased 1.63 million square kilometers (629,000 square miles). This is 358,000 square kilometers (138,000 square miles) less ice gained than the December 1981 to 2010 average. The linear rate of sea ice decline for December is 47,200 square kilometers (18,200 square miles) per year, or 3.7 percent per decade relative to the 1981 to 2010 average.

Southern exposure

As noted in our post last week, Antarctic sea ice declined at a rate well above the 1981 to 2010 average for the last three weeks of December, leading to record low extent for this time of year. This pattern has continued through the first week of 2019, with areas of the northern and eastern Weddell Sea and the central Ross Sea losing ice extent.

2018 year in review

Figure 4. This graph shows the Bering Sea ice extent for 2017 to 2018 (blue) compared to the 1979 to 2017 median (black) and the 1979 to 2017 minimum to maximum range (gray shading).

Credit: W. Meier, NSIDC
High-resolution image

Figure 4. Sea ice extent anomalies relative to 1981-2010 from 1850 to 2018 (updated from Walsh et al., 2015. Gridded Monthly Sea Ice Extent and Concentration, 1850 Onward, Version 1)

Figure 5. This figure shows departures from average sea ice extent in the Arctic Ocean relative to 1981 to 2010 from 1850 to 2018. Above average extent is shown by red and orange colors, while below average extent is shown in blue colors.

Credit: Updated from Walsh et al., 2015. Gridded Monthly Sea Ice Extent and Concentration, 1850 Onward, Version 1
High-resolution image

January 2018 began the year with record low sea ice extents for the Arctic as a whole. Regionally, below average ice extent characterized both the Kara and Barents Seas and the Chukchi and Bering Seas. This pattern continued into February and early March. The low sea ice conditions in the Bering Sea persisted throughout the entire winter and were the lowest ever recorded during the satellite record (Figure 4). In particular, the ice in the region significantly declined in February—normally the time when extent is reaching its seasonal maximum. As reported in the NOAA Arctic Report Card, during a two and a half week period in mid-February, the Bering Sea ice extent dropped by over 225,000 square kilometers (87,000 square miles), an area roughly the size of Idaho.

The seasonal maximum, reached on March 17, 2018, was the second lowest in the satellite record. While low extent persisted through April and May, sea ice loss during early summer was unremarkable despite above average 925 hPa air temperatures over the Arctic Ocean and Eurasia. Antarctica reached its second-lowest annual minimum on February 20 and 21, and extent remained low throughout the year. However, the locations of the regional departures from average shifted during the year, as is often the case. Extent in the northern and eastern margins of the Weddell Sea were persistently low.

Air temperatures over the Arctic Ocean in July were below average, followed by above average temperatures in August. In fact, on average, August temperatures were higher than July temperatures in 2018. This is highly unusual in the Arctic and something not seen in at least 40 years. Overall the June, July, and August mean 925 hPa air temperatures over the Arctic Ocean ranked as the sixth highest since 1979.

The September 2018 seasonal minimum extent ended up slightly above the long-term linear trend line, tying with 2008 for the sixth lowest in the satellite record. After the minimum, the ocean was slow to freeze up, and October sea ice extent ended up as the third lowest. However, ice growth was very rapid in November, such that November 2018 extent approached the interquartile range of the 1981 to 2010 median. Nevertheless, large amounts of open water remained in the Barents and Chukchi Seas. By the end of December, ice conditions in the Chukchi Sea were back to average, while extent remained unusually low in the Barents Sea.

Coverage of old ice (greater than 4 years old) over the Arctic continued to decline. Such old ice covers only 5 percent of the area it used to in 1980s.

It is interesting to compare these conditions to historical reconstructions. Today’s departures from average conditions are quite remarkable when viewed over the last 160+ years (Figure 5). While some lower than average (computed 1981 to 2010) winter and summer sea ice conditions occurred prior to the satellite data record, they were not as large in magnitude or as persistent as recent departures have been. Further, recent years have shown unusually low sea ice extent persisting well into autumn and winter, reflecting a distinct change in seasonality in the Arctic compared to earlier years with low summer ice conditions.

Categories: Climate Science News

A record-low start to the new year in Antarctica

NSIDC Artic Sea Ice News - Thu, 2019-01-03 10:24

As of January 1, 2019, Antarctic sea ice extent had experienced several days of record lows. These record-low extents, which followed a period of rapid ice loss in December, exemplify the high seasonal and year-to-year variability in Antarctic sea ice. With six to eight weeks remaining in the melt season, it remains to be seen whether the present situation will persist and lead to a record-low annual minimum. A discussion of Arctic conditions will be posted next week.

Overview of conditions Sea ice extent for January 1, 2019

Figure 1. Antarctic sea ice extent for January 1, 2019 was 5.47 million square kilometers (2.11 million square miles). The orange 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

On January 1, Antarctic sea ice extent stood at 5.47 million square kilometers (2.11 million square miles), the lowest extent on this date in the 40-year satellite record. This value is 30,000 square kilometers (11,600 square miles) below the previous record low for January 1, set in 2017, and 1.88 million square kilometers (726,000 square miles) below the 1981 to 2010 average. Extent declined at a rate of 253,000 square kilometers (97,700 square miles) per day through December, considerably faster than the 1981 to 2010 mean for December of 214,000 square kilometers (82,600 square miles) per day. Indeed, the rate of Antarctic ice extent loss for December 2018 is the fastest in the satellite record, albeit close to 2010 and 2005.

Conditions in context Lowest December Antarctic sea ice time series

Figure 2: Derived from NSIDC’s Charctic tool, this time series compares the six lowest December extents for Antarctic sea ice. For the 40-year satellite record, the years coming closest to the 2018 extent are 1979 and 2016. Note that the extent lines for 1979 and 1982 end on December 30 because older satellite sensors only collected data every other day. The absence of any late or early tendency in the lowest December extents indicates the lack of an overall trend in Antarctic sea ice.

Credit: W. Meier, NSIDC
High-resolution image

On December 26, Antarctic sea ice extent fell below the low mark for this date, set in 2016, and has continued to track below all other years. Notably, the November to December 2016 period was considered an extreme excursion of Antarctic sea ice at the time. However, since then Antarctic sea ice extent has continually remained below the 1981 to 2010 median and mostly below the interquartile extent (below 75 percent of the 30-year range of values). This change in behavior, which began during the austral spring of 2016, contradicts prior characterizations of Antarctic sea ice cover as slowly expanding, yet highly variable. Instead, another strong decline through late December 2018 has taken the extent below the November and December 2016 levels to new record lows. Antarctica’s high year-to-year variability (record high extents for December were observed as recently as 2014 and 2007) suggests that a conclusive sea ice trend associated with the warming air and ocean around Antarctica has yet to reveal itself.

Spatial patterns of loss Extend comparison

Figure 3a. This maps shows the difference between Antarctic sea ice extent on December 1, 2018, and January 1, 2019.

Credit: W. Meier, NSIDC
High-resolution image

The rapid ice loss through December 2018 and into early January 2019 has exposed large areas of the Southern Ocean that are typically ice-covered at this time of year. At the beginning of December 2018, a substantial band of ice ringed most of the Antarctic continent, although regions of open water had begun to appear along portions of the coast near the Amery Ice Shelf and within the ice pack to the east of the Weddell Sea (Figure 3a). Despite being ice-covered at the beginning of the month, concentrations were quite low in the eastern Weddell, eastern Ross Sea, and the region north (and to either side) of the Amery. These areas have since melted out completely. Many other areas of low concentration ice remain, particularly in the northeastern Weddell Sea and the northern Ross Sea (Figure 3b). These areas are expected to melt out soon.

Six to eight weeks remain in the Antarctic melt season. Whether the record low daily extents now being seen will persist and lead to a record seasonal minimum cannot be predicted.

Concentration and anomaly maps

Figure 3b. These maps show sea ice concentration (left) and sea ice concentration anomaly, or difference from average (right), for December 31, 2018. In the right map, blues indicate higher than average sea ice concentrations; reds indicate lower than average concentrations.

Figure courtesy of Phil Reid, Australian Bureau of Meteorology. Sea ice concentration data from NSIDC.
High-resolution image

Although it is too soon for us to isolate what caused the rapid December decline and recent record low extents, it is likely that unusual atmospheric conditions and high sea surface temperatures—important factors in the 2016 and 2017 record lows—are playing a role. Unfortunately, as of this post our usual source of atmospheric data is not accessible due to the US government shutdown. NSIDC will continue to monitor the low ice conditions in the Antarctic and will provide updated analyses through the austral summer.

Categories: Climate Science News

January 2019: From La Niña to El Niño, 20 years of Images of the Month on Aviso web site!

AVISO Climate Change News - Wed, 2019-01-02 04:32
Wandering through 20 years of Images of the Month on this web site.
Categories: Climate Science News

[Jason-2] is in safe hold mode since December 26th at 01:33:54UTC

AVISO Climate Change News - Thu, 2018-12-27 01:16
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 well known. Recovery operations will start after Christmas holidays period. Very best regards  Merry Christmas and happy New Year 2019 Nadège Quéruel (SALP on call) on behalf of Christophe Marechal, CNES Jason 2 project manager.
Categories: Climate Science News

[Jason-3] reprocessed POE delivery

AVISO Climate Change News - Thu, 2018-12-20 10:04
All POE have been reprocessed for Jason-3 in level F. From today (Dec. 20th), they can be retrieved on SEF
Categories: Climate Science News

Jason-3 reprocessed POE delivery

AVISO Climate Change News - Thu, 2018-12-20 10:04
All POE have been reprocessed for Jason-3 in level F. From today (Dec. 20th), they can be retrieved on SEF
Categories: Climate Science News

1 - 16 December 2018 weeks

AVISO Climate Change News - Tue, 2018-12-18 06:33
Snow over Antarctica buffered sea level rise during last century (Science Daily, 13/12/2018) Drones help map sea level rise (Phys.org, 12/12/2018) The Arctic Ocean has lost 95 percent of its oldest ice — a startling sign of what’s to come (Washington Post, 11/12/2018) Argo finds ocean stores 90% of the Earth's heat and water is getting saltier (Daily Mail, 10/12/2018) Another El Niño on the horizon? (Esa, 07/12/2018) Ice loss in Greenland is Accelerating (Universe Today, 06/12/2018) Portrait of a planet on the verge of climate catastrophe (The Guardian, 02/12/2018) Climat : la COP24 adopte les règles d’application de l’accord de Paris (Le Monde, 15/12/2018) COP24 : des capteurs bon marché pour surveiller les océans (Sciences & Avenir, 11/12/2018) COP24 : la France fera partie des 20 pays les plus touchés par le changement climatique (Sciences & Avenir, 07/12/2018) Augmentation de la variance des événements El Niño de l’est du Pacifique liée au réchauffement global (INSU, 07/12/2018) Surfaces enneigées records en Amérique du nord (Meteo France, 05/12/2018) La grande barrière de corail de Nouvelle-Calédonie est en danger (France Inter, 04/12/2018) On line availability of articles depends on the Newspaper/magazine. We can't thus certify that above articles will be freely and permanently available.
Categories: Climate Science News

CFOSAT: the end of the Commissioning Phase

AVISO Climate Change News - Wed, 2018-12-05 01:05
The French-Chinese satellite CFOSAT was successfully launched on October 29th (see our dedicated news). Throughout this last month, the Commissioning Phase took place with initial calibration and validation aimed at assessing the good functionality of the instruments, the final orbit and the first steps of the ground segment: reception and processing of satellite telemetry from the stations network.  The first period of the Commissioning Phase started just after launch with the switch on of the instruments. Only a few days after the launch, the SWIM status was nominal with great results for the first wave products evidencing SWIM perfect behaviour. On the Chinese side, the SCAT scatterometer dedicated to the ocean surface wind measurements was also operational and works properly (see our dedicated news). The operational orbit was quickly reached three days after the launch. Periodic station keeping maneuvers will take place to maintain the orbit close to its reference orbit and nominal tracks. The reception and processing of satellite telemetry data from Chinese and French sides have also been successfully tested and validated. The Commissioning Phase ended with these promising results, the Calibration/Validation phase is starting now where the data are available for scientific experts (represented in France by LATMOS, Ifremer/LOPS and marine forecasters and oceanographers at Météo-France).

Schema of the different development phases from the CFOSAT launch and up to the routine phase in Summer 2019. Credits CNES.

Further information:
  • Missions : CFOSAT
Categories: Climate Science News

Autumn freeze-up amps up

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

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

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

Figure 1. Arctic sea ice extent for November 2018 was 9.80 million square kilometers (3.78 million square miles). The magenta line shows the 1981 to 2010 average extent for that month. Sea Ice Index data. About the data

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

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

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

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

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

Figure 2. The graph above shows Arctic sea ice extent as of December 03, 2018, along with daily ice extent data for four previous years and the record low year. 2018 is shown in blue, 2017 in green, 2016 in orange, 2015 in brown, 2014 in purple, and 2012 in dotted brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

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

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

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

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

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

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

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

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

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

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

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

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

 Barton et al., 2018, Journal of Physical Oceanography

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

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

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

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

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

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

Antarctic note

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

Reference

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

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

Categories: Climate Science News
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