Climate Science News

29 May - 17 June 2019 Press Review

AVISO Climate Change News - Mon, 2019-06-17 09:58
Big earthquakes might make sea level rise worse. Here's how. (National Geographic, 17/06/2019) Mapped Area of Ocean Floor Doubles (The Marine Executive, 14/06/2019) Could more Hurricanes cool down the Atlantic? (News4Jax, 13/06/2019) Antarctic glaciers to honour 'satellite heroes' (BBC, 07/06/2019) Video: Perpetual ocean (EarthSky, 07/06/2019) These high-tech seals are charting future sea level rise (Pri, 03/06/2019) Antarctique : l'apparition de trous dans la banquise enfin expliquée (Science et Avenir, 14/06/2019) La plus grande opération de nettoyage de l'océan a officiellement débuté (Clubic, 09/06/2019) Espèces monstrueuses, pression phénoménale et noir complet : plongée dans les abysses avec les explorateurs des grands fonds (France TV info, 08/06/2019) La Méditerranée déborde de plastique : 600.000 tonnes rejetées par an ! (Futura planète, 07/06/2019) Océan : cartographier les fonds marins en HD en un temps record, un défi (Futura planète, 04/06/2019) Attention, trafic d'impulsions radar en or ! (CNES, 29/05/2019) 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

A glimpse on Swot satellite building and testing

AVISO Climate Change News - Fri, 2019-06-14 06:59
A few photos showing building and testing of the future satellite Swot
Categories: Climate Science News

[SARAL/Altika] Cycle 128 GDR release

AVISO Climate Change News - Wed, 2019-06-12 05:29
GDR cycle 128 (11 March 2019-15 April 2019) was just released recently. During this cycle, SARAL/AltiKa satellite regularly encountered mispointing events. The availability and the quality of data measurements continue to be degraded. Before using the data, users are still invited to remove any ocean data with “off_nadir_angle_wf” over 0.09 deg²)
Categories: Climate Science News

June 2019: Modelling the flow

AVISO Climate Change News - Fri, 2019-06-07 08:20
SWOT will provide brand new capabilities for hydrological measurements and studies. Preparation are...
Categories: Climate Science News

Warm May in the Arctic sets the stage

NSIDC Artic Sea Ice News - Tue, 2019-06-04 14:45

May saw above average temperatures over nearly all of the Arctic Ocean, Baffin Bay, and Greenland. Early sea ice retreat in the Bering Sea extended into the southern Chukchi Sea. Northern Baffin Bay and the Nares Strait have low ice cover. By month’s end, open water extended along the northeastern Alaskan and northwestern Canadian coasts, all well ahead of schedule. However, this was partly balanced by slower-than-average ice loss in the Barents Sea. At the end of May, Arctic sea ice daily extent stood at second lowest in the 40-year satellite record.

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

Figure 1. Arctic sea ice extent for May 2019 was 12.16 million square kilometers (4.70 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 averaged for May was 12.16 million square kilometers (4.70 million square miles). This is 1.13 million square kilometers (436,000 square miles) below the 1981 to 2010 average and 240,000 square kilometers (93,000 square miles) above the previous record low for the month set in May 2016. The month saw rapid ice loss in the Bering Sea and southern Chukchi Sea. During the second half of the month, an extended coastal polynya opened along the northwestern coast of the Beaufort Sea extending into the Mackenzie River Delta area. Visible MODIS imagery shows many large ice floes interspersed with open water along the ice edge and fracturing of ice further within the pack.

Although ice loss in the Barents Sea was rapid in early May, it subsequently slowed and extent slightly increased late in the month. There was nevertheless an overall ice retreat for May as a whole. Around mid-month, a polynya began to open at the north end of Baffin Bay, near the Nares Strait. At about this time, an ice arch that restrains southward ice drift in the Lincoln Sea began to fail, allowing transport of ice through the strait and creating a small polynya northwest of Greenland (discussed below). By the end of May, other polynyas started to form around the New Siberian Islands as well as Severnaya Zemlya, and open water began to develop along coastal regions in the Kara Sea and in northern Hudson Bay.

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

Figure 2a. The graph above shows Arctic sea ice extent as of June 3, 2019, along with daily ice extent data for four previous years and the record low year. 2019 is shown in blue, 2018 in green, 2017 in orange, 2016 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. 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 May 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

Broadly following the pattern for April, air temperatures at the 925 hPa level (approximately 2,500 feet above the surface) for May were again well above average over nearly all of the Arctic Ocean. Along the western Greenland coast, a broad area north of Greenland, and westward north of the Canadian Archipelago, temperatures were as much as 7 degrees Celsius (13 degrees Fahrenheit) above the 1981 to 2010 reference average for the month. Over much of the remainder of the Arctic Ocean, temperatures were 2 to 4 degrees Celsius (4 to 7 degrees Fahrenheit) above average. By contrast, over the Barents Sea as well as along the Laptev Sea coast, temperatures were near average or up to 2 degrees (4 degrees Fahrenheit) below average. As averaged for May, there was an area of high sea level pressure, an anticyclone, centered near the pole. This pattern drew warm air from the south into Baffin Bay and into the Arctic Ocean. Also, air under an anticyclone descends and warms. Both factors help to explain the unusually high temperatures over much of the Arctic Ocean.

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

Figure 3. Monthly May ice extent for 1979 to 2019 shows a decline of 2.74 percent per decade.

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

Overall, sea ice extent during May 2019 decreased by 1.49 million square kilometers (575,300 square miles). This was fairly close to the 1981 to 2010 average loss for the month. The linear rate of sea ice decline for May from 1979 to 2019 is 36,400 square kilometers (14,100 square miles) per year, or 2.74 percent per decade relative to the 1981 to 2010 average.

Ice arch break up in the Lincoln Sea  NASA| High-resolution image

Figure 4. This NASA Worldview (download to view animation) image shows sea ice in the Nares Strait from April 19 to May 11. A new Worldview functions creates an animation using Aqua Moderate Imaging Spectroradiometer (MODIS) true color composite images.

Credit: NASA
High-resolution image

In most years (2007 being a notable exception), an ice arch forms during late autumn and winter at the north end of Nares Strait, the narrow passage that separates Greenland from Ellesmere Island. This arch acts as a barrier, preventing ice from the Arctic Ocean from drifting through the strait and into Baffin Bay. The arch typically breaks up in June or July, allowing ice to drift through the narrow channel. This year, the arch broke up by late March, much earlier than is typical. Since then, there has been a steady flow of ice through Nares Strait (download animation to view). Since 2000, only four other years appear to have had similar early breakups of the arch: 2007 (when no arch formed at all), 2008, 2010, and 2017 (Moore et al., 2018). Typically, strong wind events trigger the break up, but warm temperatures and thinner ice can also contribute.

Arctic sea ice variability linked to atmospheric temperature fluctuations  NSIDC Sea Ice index and ERA-Interim Reanalysis | High-resolution image

Figure 5. The top figure shows how the year-to-year sea ice area co-varies with mid-atmosphere temperatures (average of temperatures between 850 HPa to 400 HPa, or about 5,000 to 25,000 feet above sea level). The below bar graph provides the contributions of other suggested mechanisms. Combined, they account for about 25 percent of the sea ice variations. The direct influence of mid-atmosphere temperature fluctuations remains as the primary cause of year-to-year sea-ice variations.

Credit: NSIDC Sea Ice Index and ERA-Interim Reanalysis
High-resolution image

While Arctic sea ice extent is declining sharply, it is also highly variable from one year to the next. Scientists from the Max Planck Institute for Meteorology (MPI-M) and the University of Stockholm have proposed that this strong variability is closely related to fluctuations in the air temperature above the Arctic Ocean driven by atmospheric heat transport into the Arctic from lower latitudes. In contrast to previous assumptions, they argue that other factors, such as the ice-albedo feedback, cloud and water vapor feedbacks, and oceanic heat transported into the Arctic together explain only 25 percent of the year-to-year sea ice extent variations. Most of the sea ice variations are thus directly caused by mid-atmospheric temperature conditions; this is evident in both observational data and climate models. Their study implies that year-to-year fluctuations in sea ice extent are easier to understand than previously thought. However, their study also suggests that it may be more difficult to predict the summer extent of Arctic sea ice from one year to the next, because the problem of predicting atmospheric heat transport is closely related to the challenges of long-term weather forecasting.

Antarctic sea ice extent exceptionally low in the Weddell and Amundsen Seas  National Snow and Ice Data Center|High-resolution image

Figure 6. Antarctic sea ice extent for May 2019 was 8.80 million square kilometers (3.40 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

Antarctic sea ice extent continues to climb toward its seasonal maximum, which is expected in late September or early October. At the end of May, Antarctic sea ice extent was very close to record daily lows over the period of satellite observations, previously set for the month in 1980. Unusually low ice extent in the eastern Weddell Sea and northern Amundsen Sea are responsible for the low overall total extent, with smaller areas of open water in the eastern Wilkes Land coastal region and southwestern Indian Ocean (Cosmonaut Sea). Slightly above average sea ice extent is present in the north-central Ross Sea and northwestern Weddell Sea.

References

Kwok, R., L. Toudal Pedersen, P. Gudmandsen, and S. S. Pang. 2010. Large sea ice outflow into the Nares Strait in 2007. Geophysical Research Letters. doi: 10.1029/2009GL041872.

Moore, G. W. K. and K. McNeil. 2018. The early collapse of the 2017 Lincoln Sea ice arch in response to anomalous sea ice and wind forcing. Geophysical Research Lettersdoi:10.1029/2018GL078428.

Olonscheck, D., T. Mauritsen, and D. Notz. 2019. Arctic sea-ice variability is primarily driven by atmospheric temperature fluctuations. Nature Geoscience. doi:10.1038/s41561-019-0363-1.

Categories: Climate Science News

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

AVISO Climate Change News - Wed, 2019-05-22 03:36
All core mission instruments have been restarted today on the last available pass :
  • POSEIDON at 08:54:07UTC
  • AMR at 08:56:06UTC
  • GPSP at 08:59:15UTC
The first OGDRs will be available around 10:30UTC.   As a reminder, 2 maneuvers are still necessary to place Jason-2 correctly in order to resume the geodetic cycle #2, stopped on February 16th. According to the current plans, this should be achieved on Tuesday 28th of May.
Categories: Climate Science News

1- 19 May 2019 Press review

AVISO Climate Change News - Mon, 2019-05-20 03:49
Nearly a quarter of West Antarctic ice is now unstable (University of Leeds, 16/05/2019) Water cycle wrapped (ESA, 15/05/2019) Image: Antarctica detailed in 3-D (Phys.org, 14/05/2019) Explorer Reaches Bottom of the Mariana Trench, Breaks Record for Deepest Dive Ever (LiveScience, 13/05/2019) Where Did All the Free-Flowing Rivers Go? (EOS, 08/05/2019) El Niño has rapidly become stronger and stranger, according to coral records (The Conversation, 06/05/2019) As Sea Levels Rise, Expect More Floods (EOS, 03/05/2019) Scientists track giant ocean vortex from space (EurekAlert!, 01/05/2019) Climat : avril 2019 quasi record de chaud (Le Monde, 16/05/2019) Changement climatique : six indicateurs qui montrent que la France n’est pas épargnée (Sud Ouest, 10/05/2019) 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

Saral/Altika Cycle 127 GDR release

AVISO Climate Change News - Fri, 2019-05-10 06:50
Dear SARAL/Altika users, Please take note of the disclaimer below :  GDR cycle 127 (04 February 2019-11 March 2019) was just released recently. During this cycle SARAL/AltiKa satellite regularly encountered mispointing events. The availability and the quality of data measurements continue to be degraded from time to time. CNES, EUMETSAT and ISRO inform users that removing any ocean data with “off_nadir_angle_wf” over 0.09 deg² will ensure a good data quality. Detailled information about calval analysis is given in this page. Quality assement report is available here.
Categories: Climate Science News

Maintenance on the Aviso+ Web services on May 14th 2019 between 10h and 10h15 UTC

AVISO Climate Change News - Thu, 2019-05-09 05:53
Due to a maintenace, the Aviso+ web sites will be disrupted on May 14th between 10h and 10h15 UTC. This will concern, the website, the Aviso+ extraction service, the TDS (Opendap), and the Live Access Server (LAS)
Categories: Climate Science News

Rapid ice loss in early April leads to new record low

NSIDC Artic Sea Ice News - Thu, 2019-05-02 14:45

April reached a new record Arctic low sea ice extent. Sea ice loss was rapid in the beginning of the month because of declines in the Sea of Okhotsk. The rate of ice loss slowed after early April, due in part to gains in extent in the Bering and Barents Seas. However, daily ice extent remained at record low levels throughout the month.

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

Figure 1. Arctic sea ice extent for April 2019 was 13.45 million square kilometers (5.19 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 April 2019 averaged 13.45 million square kilometers (5.19 million square miles). This was 1.24 million square kilometers (479,000 square miles) below the 1981 to 2010 long-term average extent and 230,000 square kilometers (89,000 square miles) below the previous record low set in April 2016.

Rapid ice loss occurred in the Sea of Okhotsk during the first half of April; the region lost almost 50 percent of its ice by April 18. Although sea ice was tracking at record low levels in the Bering Sea from April 1 to 12, the ice cover expanded later in the month. Elsewhere, there was little change except for small losses in the Gulf of St. Lawrence, the southern part of the East Greenland Sea, and southeast of Svalbard. In addition, open water areas developed along coastal regions of the Barents Sea. The ice edge expanded slightly east of Novaya Zemlya.

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

Figure 2a. The graph above shows Arctic sea ice extent as of May 1, 2019, along with daily ice extent data for four previous years and 2012. 2019 is shown in blue, 2018 in green, 2017 in orange, 2016 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. 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 April 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

Air temperatures at the 925 hPa level (approximately 2,500 feet above the surface) were above average across the Arctic during the first two weeks of April, especially over the East Siberian Sea and the Greenland Ice Sheet where air temperatures were as much as 9 degrees Celsius (16 degrees Fahrenheit) above average (Figure 2b). Elsewhere, 925 hPa temperatures were between 3 to 5 degrees Celsius (5 to 9 degrees Fahrenheit) above average, including the Sea of Okhotsk where ice loss early in the month was especially prominent. These relatively warm conditions were linked to a pattern of high sea level pressure over the Beaufort Sea paired with low sea level pressure over Alaska, Siberia, and the Kara and Barents Seas. This drove warm air from the south over the East Siberian Sea. Similarly, high pressure over Greenland and the North Atlantic, coupled with low sea level pressure within Baffin Bay, helped usher in warm air over southern Greenland from the southeast.

During the second half of the month, temperatures remained above average over most of the Arctic Ocean, and up to 8 degrees Celsius (14 degrees Fahrenheit) above average over the East Greenland Sea. However, temperatures were 1 to 5 degrees Celsius (2 to 9 degrees Fahrenheit) below average over the Bering Sea, and up to 8 degrees Celsius (14 degrees Fahrenheit) below average over the Canadian Arctic Archipelago. Air temperatures were slightly below average in the Kara Sea.

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

Figure 3. Monthly April ice extent for 1979 to 2019 shows a decline of 2.64 percent per decade.

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

The 1979 to 2019 linear rate of decline for April ice extent is 38,800 square kilometers (15,000 square miles) per year, or 2.64 percent per decade relative to the 1981 to 2010 average.

Sea ice age update  W. Meier, NSIDC|High-resolution image

Figure 4. The top maps compare Arctic sea ice age for (a) April 8 to 14, 1984, and (b) April 9 to 15, 2019. The time series (c) of mid-April sea ice age as a percentage of Arctic Ocean coverage from 1984 to 2019 shows the nearly complete loss of 4+ year old ice; note the that age time series is for ice within the Arctic Ocean and does not include peripheral regions where only first-year (0 to 1 year old) ice occurs, such as the Bering Sea, Baffin Bay, Hudson Bay, and the Sea of Okhotsk.

Credit: W. Meier, NSIDC
High-resolution image

Younger sea ice tends to be thinner than older ice. Therefore, sea ice age provides an early assessment of the areas most susceptible to melting out during the coming summer. The Arctic sea ice cover continues to become younger (Figure 4), and therefore, on average, thinner. Nearly all of the oldest ice (4+ year old), which once made up around 30 percent of the sea ice within the Arctic Ocean, is gone. As of mid-April 2019, the 4+ year-old ice made up only 1.2 percent of the ice cover (Figure 4c). However, 3 to 4-year-old ice increased slightly, jumping from 1.1 percent in 2018 to 6.1 percent this year. If that ice survives the summer melt season, it will somewhat replenish the 4+ year old category going into the 2019 to 2020 winter. However, there has been little such replenishment in recent years.

The sea ice age data products were recently updated through 2018 (Version 4, Tschudi et al., 2019). Data is available here. In addition, an interim QuickLook product that will provide preliminary updates every month is in development.

Changing ice and sediment transport  T. Krumpen|High-resolution image

Figure 5a. This map shows the main sea ice drift patterns.
Figure 5b. This illustration shows how sediments can be ingrained into the newly forming sea ice.
Figure 5c. This graph shows the probability that newly formed ice in the winter will survive the summer.

Credit: T. Krumpen
High-resolution image

 R. Stein, AWI, 2014.

Figure 5d. This image shows sediment-rich sea ice in the Transpolar Drift Stream. A crane lowers two researchers from the decks of the icebreaker RV Polarstern to the surface of the ice to collect samples.

Photo Credit: R. Stein, Alfred Wegener Institut
High-resolution image

Scientists from the Alfred Wegener Institut (AWI) monitored and analyzed sea ice motion using satellite data from 1998 to 2017 and concluded that only 20 percent of the sea ice that forms in the shallow Russian seas of the Arctic Ocean now reaches the central Arctic Ocean to join the Transpolar Drift Stream (Figures 5a and b). The Russian seas, including the Kara, Laptev, and East Siberian Seas, are considered the ice nursery of the Arctic. The remaining 80 percent of this first-year ice melts before it has a chance to leave this nursery. Prior to the year 2000, that number was about 50 percent (Figure 5c).

These conclusions find support from sea ice thickness observations in Fram Strait, which is fed by the Transpolar Drift Stream. AWI scientists regularly gather ice thickness data in Fram Strait as part of their IceBird program. The ice now leaving the Arctic Ocean through the Fram Strait is, on average, 30 percent thinner than it was 15 years ago. There are two reasons for this. First, winters are warmer and the melt season now begins much earlier than it used to. Second, much of this ice no longer forms in the shallow seas, but much farther north. As a result, it has less time to thicken from winter growth and/or ridging as it drifts across the Arctic Ocean.

These changes in transport and melt affect biogeochemical fluxes and ecological processes in the central Arctic Ocean. For example, in the past, the sea ice that formed along the shallow Russian seas transported mineral material, including dust from the tundra and steppe, to the Fram Strait (Figure 5d). Today, the melting floes release this material en route to the central Arctic Ocean. Far less material now reaches the Fram Strait and it is different in composition. This finding is based on two decades of data sourced from sediment traps maintained in the Fram Strait by AWI biologists. Instead of Siberian minerals, sediment traps now contain remains of dead algae and microorganisms that grew within the ice as it drifted.

Putting current changes into longer-term perspective Figure6updated

Figure 6. This map shows Arctic regions used in the Walsh et al. study and how much each area’s September extent contributes to the total September sea ice extent. The top number gives the percentage (as squares of correlations, or R2) when the raw 1953 to 2013 ice extent time series is used. The bottom number (bold) gives what the percentage drops to after the time series data have been detrended. For example, about 70 percent of the September Arctic-wide extent number is explained by the September extent in the seas north of Alaska, but that drops to about 20 percent once the trends have been removed.

Credit: Walsh et al., 2019, The Cryosphere
High-resolution image

While changes in sea ice extent over the past several decades are usually shown as linear trends, they can mask important variations and changes. A recent study led by John Walsh at University Alaska Fairbanks compared various trend-line fits to sea ice extent time series back to 1953, for the Arctic as a whole and various sub-regions. This data set extends the satellite record by using operational ice charts and other historical sources (Walsh et al., 2016). They found that a two-piece linear fit with a break point in the 1990s provides a more meaningful basis for calculations of sea ice departures from average conditions and their persistence, rather than a single trend line computed over the period 1953 to the present. Persistence of sea ice departures from average conditions represents the memory of the system, which can be used to forecast sea ice conditions a few months in advance. September Arctic-wide ice extent can also be predicted with some limited skill when the data include the trend. However, this apparent skill largely vanishes when the trend is removed from the data using the two-piece linear fit. This finding is consistent with the notion of a springtime predictability barrier, such that springtime sea ice conditions are usually not a strong predictor of the summer ice cover because atmospheric circulation patterns in summer erode this memory in the system. For example, despite the extensive coverage of fairly young—and hence thin—ice this spring, cool summer weather conditions may limit melt, leading to a higher September ice extent than might otherwise be expected.

April snow melt in Greenland—notable but not unusual

Temperatures were well above average over Greenland for much of April but were still below freezing except near the coast. Satellite data indicate that there was a small area surface melt on the southeastern coastal part of the ice sheet early in the month. In the last week of April, melt became more extensive, spreading further north on the east coast and starting on the west coast. While interesting, this is not especially unusual. Most years of the past decade have some surface melt in April. In 2012 and 2016, strong melt events occurred in April that covered a much larger area than in 2019. NSIDC is now tracking Greenland surface melt for 2019 on a daily basis.

Further reading

Krumpen, T., H. J. Belter, A. Boetius, E. Damm, C. Haas, S. Hendricks, M. Nicolaus, E.-M. Nöthig, S. Paul, I. Peeken, R. Ricker, and R. Stein. 2019. Arctic warming interrupts the Transpolar Drift and affects long range transport of sea ice and ice-rafted matter. Scientific Reports. doi:10.1038/s41598-019-41456-y.

Tschudi, M. A., W. N. Meier, and J. S. Stewart. 2019. An enhancement to sea ice motion and age products. The Cryosphere Discussion, in review. doi:10.5194/tc-2019-40.

Walsh, J. E., W. L. Chapman, and F. Fetterer. 2015, updated 2016. Gridded Monthly Sea Ice Extent and Concentration, 1850 Onward, Version 1. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi:10.7265/N5833PZ5.

Walsh, J. E., J. S. Stewart, and F. Fetterer. 2019. Benchmark seasonal prediction skill estimates based on regional indices. The Cryosphere. doi:10.5194/tc-13-1073-2019.

The Alfred Wegener Institute (AWI) IceBird Program

Categories: Climate Science News

May 2019: Liguro-Provençal current seen by in situ instruments and altimetry

AVISO Climate Change News - Tue, 2019-04-30 17:01
A multidata combined approach is a unique way to obtain a complete picture of a system as complex...
Categories: Climate Science News

[SARAL/Altika] Data quality : back to normal

AVISO Climate Change News - Fri, 2019-04-26 07:59
Dear SARAL/Altika users,  We are pleased to inform you that the quality of data is almost back to normal. Indeed, ISRO teams have improved the pointing stability thanks to new operational procedures. Since April 19th 2019, the availability and the quality of data measurements are better (small time to time limited effects may anyway occur). Therefore, before using the data, Users are still invited to remove any ocean data with “off_nadir_angle_wf” over 0.09 deg²)
Categories: Climate Science News

[SARAL/Altika] Data quality : back to normal

AVISO Climate Change News - Fri, 2019-04-26 07:52
Dear SARAL/Altika users,  We are pleased to inform you that the quality of data is almost back to normal. Indeed, ISRO teams have improved the pointing stability thanks to new operational procedures. Since April 19th 2019, the availability and the quality of data measurements are better (small time to time limited effects may anyway occur). Therefore, before using the data, Users are still invited to remove any ocean data with “off_nadir_angle_wf” over 0.09 deg²)
Categories: Climate Science News

Article on line: Scientists Invited to Collaborate in Satellite Mission’s Debut

AVISO Climate Change News - Thu, 2019-04-25 08:35
Available on EOS: Scientists Invited to Collaborate in Satellite Mission’s Debut

The Surface Water and Ocean Topography mission will begin by scanning Earth’s surface once a day. We invite ocean scientists to contribute ground-based measurements to compare with the satellite data.

By Rosemary Morrow, Lee-Lueng Fu, Francesco D’Ovidio, and J. Thomas Farrar See also: - Swot Orbit page - Image of the Month, July 2018: Adopting a Swot crossover for biophysical studies
Categories: Climate Science News

Release of Jason-3 and Saral/Altika GDR annual validation reports 2018

AVISO Climate Change News - Tue, 2019-04-23 02:05
The executive summaries give the essential results of the validation: Jason-3 and Saral/Altika.  The annual reports describe the complete and detailed analysis: Jason-3 and Saral/Altika.  Find here more information about the Calibration and Validation (CalVal) activities.
Categories: Climate Science News

[Saral/AltiKa] Data information

AVISO Climate Change News - Fri, 2019-04-19 01:26

Dear SARAL/Altika users,

 Please take note of the disclaimer below :

 SARAL/AltiKa satellite encounters since 3rd of February 2019 some issues affecting the nadir pointing accuracy. ISRO Operational Team in charge of the platform is doing many efforts to fix the issues and to recover a nominal mission as soon as possible.  

The availability and the quality of data measurements is degraded from time to time. Nevertheless, Cnes, EUMETSAT and ISRO have decided to continue the dissemination of the near real time and off-line products;  Therefore, before using the data, Users are invited to remove any ocean data with “off_nadir_angle_wf” over 0.09 deg²; otherwise standard quality flags may be used.

 

GDR cycle 126 (31 December 2018-04 February 2019 is just released today. It covers the beginning of the degraded period and you are encouraged to read the associated Cal/Val report available on AVISO+. In brief, during this cycle mispointing is quite larger than usual from pass 962 (03/02/2019 06:21:18 ) due to this attitude deviation. Hence a higher percentage of rejected measurements (up to  80%) is observed starting at pass 962. The attitude deviation also explains the higher percentage of missing measurements Users are advised not to use data with off_nadir_angle > 0.09deg².

Categories: Climate Science News

[Saral/AltiKa] Data information

AVISO Climate Change News - Thu, 2019-04-18 00:24
Dear SARAL/Altika users,  Please take note of the disclaimer below :  SARAL/AltiKa satellite encounters since 3rd of February 2019 some issues affecting the nadir pointing accuracy. ISRO Operational Team in charge of the platform is doing many efforts to fix the issues and to recover a nominal mission as soon as possible.   The availability and the quality of data measurements is degraded from time to time. Nevertheless, Cnes, EUMETSAT and ISRO have decided to continue the dissemination of the near real time and off-line products;  Therefore, before using the data, Users are invited to remove any ocean data with “off_nadir_angle_wf” over 0.09 deg²; otherwise standard quality flags may be used. GDR cycle 126 (31 December 2018-04 February 2019 is just released today. It covers the beginning of the degraded period and you are encouraged to read the associated Cal/Val report available on AVISO+. In brief, during this cycle mispointing is quite larger than usual from pass 962 (03/02/2019 06:21:18 ) due to this attitude deviation. Hence a higher percentage of rejected measurements (up to  80%) is observed starting at pass 962. The attitude deviation also explains the higher percentage of missing measurements Users are advised not to use data with off_nadir_angle > 0.09deg².
Categories: Climate Science News

AVISO+ user satisfaction survey 2019

AVISO Climate Change News - Tue, 2019-04-16 02:37
Please find the survey at the following address
https://www.aviso.altimetry.fr/en/survey/survey-2019.html This anonymous 5-7 minute-questionnaire aims at improving the quality of our products and services. It includes three subparts with questions about:
  • What altimeter user are you ?
  • The website Aviso+
  • The User Service Desk
     
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Categories: Climate Science News

[Jason-3] Jason-3 is back

AVISO Climate Change News - Fri, 2019-04-12 02:16

This Morning, on a pass at 07:00UTC(i.e. on cycle 116, pass 246) all JASON-3 core mission instruments were restarted :

-POSEIDON at 07:16:24UTC

-AMR at 07:18:12UTC

-GPSPB at 07:20:01UTC

The first post-SHM mission telemetry has been delivered. First IGDRs will be Distributed on Monday April 15th.

Categories: Climate Science News

[Jason-3]The Jason-3 spacecraft entered safe mode on Saturday, April 6, 2019 at 23:17:22 UTC

AVISO Climate Change News - Tue, 2019-04-09 01:26
The Jason-3 spacecraft entered safe mode on Saturday, April 6, 2019 at 23:17:22 UTC, immediately interrupting its measurements. SEALEVEL j3 datasets in NRT are no longer updated with fresh data up to the recovery of the mission.   Investigation in progress on CNES side, the root cause has not yet been identified.
Categories: Climate Science News
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