NASA satellites see Arctic surface darkening faster

The retreat of ocean ice within the Arctic Sea is diminishing Earth's albedo, or reflectivity, by a sum substantially bigger than formerly believed, according to a different study that utilizes data from instruments that fly aboard several NASA satellites.

The research, carried out by scientists at Scripps Institution of Oceanography, in the College of California, North Park, uses data in the Clouds and Earth's Radiant Energy System, or CERES, instrument. You will find CERES instruments aboard NASA's Tropical Rain fall Measurement Mission, or TRMM, satellite, Terra, Aqua and NASA-NOAA's Suomi National Polar-revolving about Partnership (Suomi NPP) satellites. The very first CERES instrument was released in December of 1997 aboard TRMM.

Because the ocean ice touches, its whitened reflective surface is changed with a relatively dark sea surface. This reduces the quantity of sunlight being deflected to space, leading to Earth to soak up an growing quantity of solar power.

The Arctic has warmed by 3.6 F (2 C) because the seventies. The summer time minimum Arctic ocean ice extent has decreased by 40 % throughout the same time frame period. These 4 elements have decreased the region's albedo, or even the fraction of incoming light that Earth reflects back to space -- a big change the CERES instruments can measure.

Scripps graduate student Kristina Pistone and climate researchers Ian Eisenman and Veerabhadran Ramanathan used satellite dimensions to calculate Arctic albedo changes connected using the altering ocean ice cover. Albedo is measured like a percentage. A wonderfully black surface comes with an albedo of 0 % along with a perfectly whitened surface comes with an albedo of 100 %. The albedo of fresh snow is usually between 80 and 90 % whereas the albedo from the sea surface is under 20 %. Clouds along with other factors, like aerosols and black carbon, also influence the albedo of Earth.

The scientists calculated the overall albedo from the Arctic region fell from 52 percent to 48 percent between 1979 and 2011. The magnitude of surface darkening is two times as huge as that present in previous studies. Additionally they in comparison their leads to model simulations to evaluate the capacity laptop or computer models to portray and forecast albedo changes.

Previous research has used a mix of computer models and findings within their information to estimate just how much extra energy continues to be absorbed through the oceans. In comparison, the Scripps team elected to directly correlate albedo dimensions produced by NASA's CERES instrument data with findings of ocean ice extent produced by the Special Sensor Microwave Imager (SSM/I) radiometers aboard Defense Meteorological Satellite Program satellites. This method prevented the potential of systematic issues in computer models.

"It's fairly intuitive to anticipate that changing whitened, reflective ocean ice having a dark sea surface would increase the quantity of photo voltaic heating," stated Pistone. "We used actual satellite dimensions of both albedo and ocean ice in the area to ensure this and also to evaluate just how much extra warmth the location has absorbed because of the ice loss. It had been quite encouraging to determine how good the 2 datasets -- that can come from two independent satellite instruments -- agreed with one another."

The Nation's Science Foundation-funded study seems within the journal Proceedings from the Nas 45 years after atmospheric researchers Mikhail Budyko and William Retailers hypothesized the Arctic would amplify climatic change as ocean ice melted.

"Researchers have spoken about Arctic melting and albedo decrease for pretty much half a century,Inch stated Ramanathan, a distinguished professor of climate and atmospheric sciences at Scripps that has formerly carried out similar research around the global dimming results of aerosols. "This is actually the very first time this darkening effect continues to be recorded around the scale from the entire Arctic."

Eisenman, a helper professor of climate dynamics, stated the outcomes of the research reveal that the heating caused by albedo changes triggered by Arctic ocean ice retreat is "quite large." Averaged within the entire globe, it's one-4th as huge as the heating triggered by growing atmospheric CO2 levels throughout exactly the same period.

The NASA dataset utilized in this research includes a merging of CERES data and dimensions in the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, which flies on two same satellites as CERES -- namely the Terra and Aqua satellites. MODIS has the capacity to separate clouds and ocean ice, that have similar brightness. This capacity helps enhance the precision from the CERES albedo blood pressure measurements, stated Norman Loeb, CERES principal investigator.

"By taking advantage of the initial abilities of synchronised CERES and MODIS dimensions, the NASA satellite data enable studies how albedo is altering with unparalleled detail and precision," stated Loeb.

To learn more about NASA's CERES instrument, visit: http://ceres.larc.nasa.gov/

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Arctic melt season lengthening, sea quickly warming

The size of the melt season for Arctic ocean ice keeps growing by a number of days each decade, as well as an earlier begin to the melt months are permitting the Arctic Sea to soak up enough additional photo voltaic radiation occasionally to melt around four ft from the Arctic ice cap's thickness, according to a different study by National Ice and snow Data Center (NSIDC) and NASA scientists.

Arctic ocean ice has been around sharp decline throughout the final 40 years. The ocean ice cover is diminishing and loss, making researchers think an ice-free Arctic Sea throughout the summer time may be arrived at this century. The seven cheapest September ocean ice extents within the satellite record have happened previously seven years.

"The Arctic is warming which is leading to the melt season to keep going longer,Inch stated Julienne Stroeve, a senior researcher at NSIDC, Boulder and lead author from the new study, that has been recognized for publication in Geophysical Research Letters. "The lengthening from the melt months are permitting for a lot of sun's energy to obtain saved within the sea while increasing ice melt throughout the summer time, overall weakening the ocean ice cover."

To review the evolution of ocean ice melt onset and freeze-up dates from 1979 to the current day, Stroeve's team used passive microwave data from NASA's Nimbus-7 Checking Multichannel Microwave Radiometer, and also the Special Sensor Microwave/Imager and also the Special Sensor Microwave Imager and Sounder transported onboard Defense Meteorological Satellite Program spacecraft.

When snow and ice start to melt, the existence of water causes spikes within the microwave radiation the snow grains emit, which these sensors can identify. When the melt months are entirely pressure, the microwave emissivity from the snow and ice balances, also it does not change again before the start of the freezing season causes another group of spikes. Researchers can appraise the alterations in the ice's microwave emissivity utilizing a formula produced by Thorsten Markus, co-author from the paper and chief from the Cryospheric Sciences Laboratory at NASA's Goddard Space Flight Center in Greenbelt, Md.

Results reveal that even though the melt months are lengthening at both finishes, by having an earlier melt onset early in the year along with a later freeze-in the autumn, the predominant phenomenon stretching the melting may be the later start of freeze season. Some areas, like the Beaufort and Chukchi Seas, are freezing between six and 11 days later per decade. But while melt onset versions are more compact, the timing of the start of the melt season includes a bigger effect on the quantity of photo voltaic radiation absorbed through the sea, because its timing coincides with once the sun is greater and better within the Arctic sky.

Despite large regional versions at first and finish from the melt season, the Arctic melt season has extended normally by 5 days per decade from 1979 to 2013.

Still, weather helps make the timing from the fall freeze-up vary so much from year upon year.

"There's a trend later on freeze-up, but we can not tell whether a specific year will have an early on or later freeze-up," Stroeve stated. "There remains lots of variability from year upon year regarding the exact timing of once the ice will reform, which makes it hard for industry to organize when you should stop procedures within the Arctic."

To determine alterations in the quantity of solar power absorbed through the ice and sea, the scientists checked out the evolution of ocean surface temps and analyzed monthly surface albedo data (the quantity of solar power reflected through the ice and also the sea) along with the incoming photo voltaic radiation for that several weeks of May through October. The albedo and ocean surface temperature data the scientists used originates from the nation's Oceanic and Atmospheric Administration's polar-revolving about satellites.

They discovered that the ice pack and sea waters are absorbing increasingly more sunlight due both for an earlier opening from the waters along with a darkening from the ocean ice. The ocean ice cover has become less reflective since it now mostly includes thinner, more youthful ice, that is less reflective compared to older ice that formerly centered the ice pack. Also, the youthful ice is flatter, permitting the dark melt ponds that form in the initial phases from the melt season can spread more broadly, further lowering its albedo.

The scientists calculated the rise in photo voltaic radiation absorbed through the ice and sea for that period varying from 2007 to 2011, which in certain regions of the Arctic Sea exceed 300 to 400 megajoules per square meter, or the quantity of energy required to thin the ice by yet another 3.1 to 4.2 ft (97 to 130 centimeters).

The increases in surface sea temps, coupled with a warming Arctic atmosphere because of global warming, explain the postponed freeze in the autumn.

"If air and sea temps offer a similar experience, the sea won't lose warmth towards the atmosphere as quickly as it might once the variations are greater," stated Linette Boisvert, co-author from the paper along with a cryospheric researcher at Goddard. "Within the last years, top of the sea warmth submissions are much greater than it was once, so it takes a longer period to awesome off as well as for freeze as much as begin."

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Periodic Arctic summer time ice extent still difficult to forecast, study states

Will next year's summer time Arctic ice extent be low or high? Can ship captains intend on moving the famous Northwest Passage -- an immediate shipping route from Europe to Asia over the Arctic Sea -- to reduce some time and fuel? New research states year-to-year predictions from the Arctic's summer time ice extent are not reliable.

Researchers in the National Ice and snow Data Center (NSIDC), College College London, College of Nh and College of Washington examined 300 summer time Arctic ocean ice predictions from 2008 to 2013 and located that predictions are very accurate when ocean ice the weather is near to the downward trend that's been noticed in Arctic ocean ice during the last 3 decades. However, predictions aren't so accurate when ocean ice the weather is abnormally greater or lower in comparison for this trend.

"We discovered that in a long time once the ocean ice extent departed strongly in the trend, such as with 2012 and 2013, forecasts unsuccessful no matter the technique accustomed to forecast the September ocean ice extent," stated Julienne Stroeve, a senior researcher at NSIDC and professor at College of school London. Stroeve is lead author from the study, released lately in Geophysical Research Letters.

"That downward trend reflects Arctic global warming, but what causes yearly versions round the trend are not as easy to pin lower," stated Lawrence Hamilton, co-author along with a investigator in the College of Nh. "This assortment of predictions from a variety of sources highlights where they are doing well, where more jobs are needed."

Arctic ocean ice cover develops each winter as sunset for many several weeks, and reduces each summer time because the sun increases greater within the northern sky. Every year, the Arctic ocean ice reaches its minimum extent in September. Researchers consider Arctic ocean ice like a sensitive climate indicator and track this minimum extent each year to ascertain if any trends emerge.

Multi-funnel passive microwave satellite instruments happen to be monitoring ocean ice extent since 1979. Based on the data, September ocean ice extent from 1979 to 2013 has rejected 13.7 percent per decade. The current years have proven a much more dramatic decrease in Arctic ice. In September 2012, Arctic ocean ice arrived at an archive minimum: 16 percent less than any previous September since 1979, and 45 percent less than the typical ice extent from 1981 to 2010.

Lengthy-term forecasts of summer time Arctic extent produced by global climate models (GCMs) claim that the downward trend will probably result in an ice-free Arctic summer time in the center of a lifetime. GCMs have been in overall agreement on lack of Arctic summer time ocean ice consequently of anticipated warming from the increase in green house gases this century.

Shorter-term predictions of summer time ice extent are not as easy to create but have reached popular. The diminishing ice has caught the interest of seaside towns within the Arctic and industries thinking about removing assets as well as in a shorter shipping route between Asia and europe.

Most of the predictions examined within the study centered on the condition from the ice cover just before the summer time melt season. Based on the study, including ocean ice thickness and concentration could enhance the periodic predictions.

"It might be also easy to predict ocean ice cover annually ahead of time rich in-quality findings of ocean ice thickness and snow cover within the whole Arctic," stated Cecilia Bitz, co-author and professor of atmospheric sciences in the College of Washington.

"Temporary forecasts are achievable, but challenges stay in predicting anomalous years, and there's an excuse for better data for initialization of forecast models," Stroeve stated. "Obviously there's always the problem that people cannot predict the elements, and summer time weather designs remain important."

The research examined predictions from study regarding Environment Arctic Change (SEARCH) Ocean Ice Outlook, a task that gathers and summarizes ocean ice predictions produced by ocean ice scientists and conjecture centers. Contributing factors towards the SEARCH Ocean Ice Outlook project employ a number of strategies to forecast the September ocean ice extent, varying from heuristic, to record, to stylish modeling approaches.

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Rainfall to blame for decline in Arctic peregrines

Rain, crucial to sustaining life on Earth, is proving deadly for young peregrine falcons in Canada's Arctic.

A University of Alberta study recently published in Oecologia shows that an increase in the frequency of heavy rain brought on by warmer summer temperatures is posing a threat not seenin this species since before pesticides such as DDT were banned from use in Canada in 1970.

The study is among the first to directly link rainfall to survival of wild birds in Canada.

A nest-box experiment at the heart of the study, co-written by U of A researcher Alastair Franke and Alexandre Anctil of the Universit? du Qu?bec, has provided "unequivocal evidence" that gradual changes in Arctic temperature and precipitation are responsible for a long-term decline in reproduction for the peregrine, a top predator in the Arctic.

The change in rainfall patterns in recent years has had a big influence on the overall decline in reproductive success over the last three decades, Franke said.

Paired with historical weather data and measures of breeding success dating back to 1980, the researchers also conducted a nest-box experiment from 2008 to 2010 in a dense population of peregrines breeding near Rankin Inlet in Nunavut on the shores of the Hudson Bay. Falcon nests were monitored using motion-sensitive cameras, and images confirmed that more than one-third of the chick deaths recorded were indeed caused by rain, whether they were raised in nest boxes or on natural ledges.

"The nestlings died from hypothermia and in some cases from drowning in their flooded nests. Without constant parental care, they are most vulnerable to cold and wet conditions in the first three weeks of life."

Over the past 30 years, scientists have been surprised to discover an ongoing decline, even when pesticide residues were known to be too low to cause reproductive failure.

"We knew DDT was no longer an issue and based on field observations, we wondered whether changes in climate were responsible for high mortality in recent years," Franke said.

Besides deaths attributed to rainfall, the study also revealed additional fallout for chicks: starvation.

"We were surprised to find that a considerable number of nestlings raised in nest boxes later died of starvation despite having been spared from the direct effects of rain."

Believing that storms may also be the culprit in reducing the abundance of prey for peregrines, Franke has launched a food supplementation study to explore the possible link.

Grim as the study's findings are, "they have improved our understanding of the direct effects of long-term changes in weather patterns and have identified the potential importance of indirect effects," Franke said.

The work also shows that wildlife can be sensitive to many different environmental pressures and that ongoing vigilance and monitoring is critical, he noted.

The study was funded by ArcticNet, the U of A's Canadian Circumpolar Institute, the Nunavut Wildlife Management Board and Department of Environment, the Natural Sciences and Engineering Research Council of Canada, the Fonds de recherche Nature et technologies Qu?bec and a W. Garfield Weston Award.

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