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  • richardmitnick 8:58 am on April 23, 2018 Permalink | Reply
    Tags: , , , Everything You Ever Wanted to Know About Earth’s Past Climates, , NASA Earth Observatory,   

    From Smithsonian.com: “Everything You Ever Wanted to Know About Earth’s Past Climates” 

    smithsonian
    Smithsonian.com

    April 16, 2018
    Rachel E. Gross

    They have a lot to tell us about our future.


    1:23:37

    In Silent Spring, Rachel Carson considers the Western sagebrush. “For here the natural landscape is eloquent of the interplay of forces that have created it,” she writes. “It is spread before us like the pages of an open book in which we can read why the land is what it is, and why we should preserve its integrity. But the pages lie unread.” She is lamenting the disappearance of a threatened landscape, but she may just as well be talking about markers of paleoclimate.

    To know where you’re going, you have to know where you’ve been. That’s particularly true for climate scientists, who need to understand the full range of the planet’s shifts in order to chart the course of our future. But without a time machine, how do they get this kind of data?

    Like Carson, they have to read the pages of the Earth. Fortunately, the Earth has kept diaries. Anything that puts down yearly layers—ocean corals, cave stalagmites, long-lived trees, tiny shelled sea creatures—faithfully records the conditions of the past. To go further, scientists dredge sediment cores and ice cores from the bottom of the ocean and the icy poles, which write their own memoirs in bursts of ash and dust and bubbles of long-trapped gas.

    In a sense, then, we do have time machines: Each of these proxies tells a slightly different story, which scientists can weave together to form a more complete understanding of Earth’s past.

    In March, the Smithsonian Institution’s National Museum of Natural History held a three-day Earth’s Temperature History Symposium that brought teachers, journalists, researchers and the public together to enhance their understanding of paleoclimate. During an evening lecture, Gavin Schmidt, climate modeler and director of NASA’s Goddard Institute for Space Studies, and Richard Alley, a world-famous geologist at Pennsylvania State University, explained how scientists use Earth’s past climates to improve the climate models we use to predict our future.

    Here is your guide to Earth’s climate pasts—not just what we know, but how we know it.

    How do we look into Earth’s past climate?

    It takes a little creativity to reconstruct Earth’s past incarnations. Fortunately, scientists know the main natural factors that shape climate. They include volcanic eruptions whose ash blocks the sun, changes in Earth’s orbit that shift sunlight to different latitudes, circulation of oceans and sea ice, the layout of the continents, the size of the ozone hole, blasts of cosmic rays, and deforestation. Of these, the most important are greenhouse gases that trap the sun’s heat, particularly carbon dioxide and methane.

    As Carson noted, Earth records these changes in its landscapes: in geologic layers, fossil trees, fossil shells, even crystallized rat pee—basically anything really old that gets preserved. Scientists can open up these diary pages and ask them what was going on at that time. Tree rings are particularly diligent record-keepers, recording rainfall in their annual rings; ice cores can keep exquisitely detailed accounts of seasonal conditions going back nearly a million years.

    1
    Ice cores reveal annual layers of snowfall, volcanic ash and even remnants of long-dead civilizations. (NASA’s Goddard / Ludovic Brucker)

    What else can an ice core tell us?

    “Wow, there’s so much,” says Alley, who spent five field seasons coring ice from the Greenland ice sheet. Consider what an ice core actually is: a cross-section of layers of snowfall going back millennia.

    When snow blankets the ground, it contains small air spaces filled with atmospheric gases. At the poles, older layers become buried and compressed into ice, turning these spaces into bubbles of past air, as researchers Caitlin Keating-Bitonti and Lucy Chang write in Smithsonian.com. Scientists use the chemical composition of the ice itself (the ratio of the heavy and light isotopes of oxygen in H2O) to estimate temperature. In Greenland and Antarctica, scientists like Alley extract inconceivably long ice cores—some more than two miles long!

    Ice cores tell us how much snow fell during a particular year. But they also reveal dust, sea salt, ash from faraway volcanic explosions, even the pollution left by Roman plumbing. “If it’s in the air it’s in the ice,” says Alley. In the best cases, we can date ice cores to their exact season and year, counting up their annual layers like tree rings. And ice cores preserve these exquisite details going back hundreds of thousands of years, making them what Alley calls “the gold standard” of paleoclimate proxies.

    Wait, but isn’t Earth’s history much longer than that?

    Yes, that’s right. Paleoclimate scientists need to go back millions of years—and for that we need things even older than ice cores. Fortunately, life has a long record. The fossil record of complex life reaches back to somewhere around 600 million years. That means we have definite proxies for changes in climate going back approximately that far. One of the most important is the teeth of conodonts—extinct, eel-like creatures—which go back 520 million years.

    But some of the most common climate proxies at this timescale are even more miniscule. Foraminifera (known as “forams”) and diatoms are unicellular beings that tend to live on the ocean seafloor, and are often no bigger than the period at the end of this sentence. Because they are scattered all across the Earth and have been around since the Jurassic, they’ve left a robust fossil record for scientists to probe past temperatures. Using oxygen isotopes in their shells, we can reconstruct ocean temperatures going back more than 100 million years ago.

    “In every outthrust headland, in every curving beach, in every grain of sand there is a story of the earth,” Carson once wrote. Those stories, it turns out, are also hiding in the waters that created those beaches, and in creatures smaller than a grain of sand.

    2
    Foraminifera. (Ernst Haeckel)

    How much certainty do we have for deep past?

    For paleoclimate scientists, life is crucial: if you have indicators of life on Earth, you can interpret temperature based on the distribution of organisms.

    But when we’ve gone back so far that there are no longer even any conodont teeth, we’ve lost our main indicator. Past that we have to rely on the distribution of sediments, and markers of past glaciers, which we can extrapolate out to roughly indicate climate patterns. So the further back we go, the fewer proxies we have, and the less granular our understanding becomes. “It just gets foggier and foggier,” says Brian Huber, a Smithsonian paleobiologist who helped organize the symposium along with fellow paleobiologist research scientist and curator Scott Wing.

    How does paleoclimate show us the importance of greenhouse gases?

    Greenhouse gases, as their name suggests, work by trapping heat. Essentially, they end up forming an insulating blanket for the Earth. (You can get more into the basic chemistry here.) If you look at a graph of past Ice Ages, you can see that CO2 levels and Ice Ages (or global temperature) align. More CO2 equals warmer temperatures and less ice, and vice versa. “And we do know the direction of causation here,” Alley notes. “It is primarily from CO2 to (less) ice. Not the other way around.”

    We can also look back at specific snapshots in time to see how Earth responds to past CO2 spikes. For instance, in a period of extreme warming during Earth’s Cenozoic era about 55.9 million years ago, enough carbon was released to about double the amount of CO2 in the atmosphere. The consequentially hot conditions wreaked havoc, causing massive migrations and extinctions; pretty much everything that lived either moved or went extinct. Plants wilted. Oceans acidified and heated up to the temperature of bathtubs.

    Unfortunately, this might be a harbinger for where we’re going. “This is what’s scary to climate modelers,” says Huber. “At the rate we’re going, we’re kind of winding back time to these periods of extreme warmth.” That’s why understanding carbon dioxide’s role in past climate change helps us forecast future climate change.

    That sounds pretty bad.

    Yep.

    I’m really impressed by how much paleoclimate data we have. But how does a climate model work?

    Great question! In science, you can’t make a model unless you understand the basic principles underlying the system. So the mere fact that we’re able to make good models means that we understand how this all works. A model is essentially a simplified version of reality, based on what we know about the laws of physics and chemistry. Engineers use mathematical models to build structures that millions of people rely on, from airplanes to bridges.

    Our models are based on a framework of data, much of which comes from the paleoclimate proxies scientists have collected from every corner of the world. That’s why it’s so important for data and models to be in conversation with each other. Scientists test their predictions on data from the distant past, and try to fix any discrepancies that arise. “We can go back in time and evaluate and validate the results of these models to make better predictions for what’s going to happen in the future,” says Schmidt.

    Here’s a model:

    3

    It’s pretty. I hear the models aren’t very accurate, though.

    By their very nature, models are always wrong. Think of them as an approximation, our best guess.

    But ask yourself: do these guesses give us more information than we had previously? Do they provide useful predictions we wouldn’t otherwise have? Do they allow us to ask new, better questions? “As we put all of these bits together we end up with something that looks very much like the planet,” says Schmidt. “We know it’s incomplete. We know there are things that we haven’t included, we know that we’ve put in things that are a little bit wrong. But the basic patterns we see in these models are recognizable … as the patterns that we see in satellites all the time.”

    So we should trust them to predict the future?

    The models faithfully reproduce the patters we see in Earth’s past, present—and in some cases, future. We are now at the point where we can compare early climate models—those of the late 1980s and 1990s that Schmidt’s team at NASA worked on—to reality. “When I was a student, the early models told us how it would warm,” says Alley. “That is happening. The models are successfully predictive as well as explanatory: they work.” Depending on where you stand, that might make you say “Oh goody! We were right!” or “Oh no! We were right.”

    To check models’ accuracy, researchers go right back to the paleoclimate data that Alley and others have collected. They run models into the distant past, and compare them to the data that they actually have.

    “If we can reproduce ancient past climates where we know what happened, that tells us that those models are a really good tool for us to know what’s going to happen in the future,” says Linda Ivany, a paleoclimate scientist at Syracuse University. Ivany’s research proxies are ancient clams, whose shells record not only yearly conditions but individual winters and summers going back 300 million years—making them a valuable way to check models. “The better the models get at recovering the past,” she says, “the better they’re going to be at predicting the future.”

    Paleoclimate shows us that Earth’s climate has changed dramatically. Doesn’t that mean that, in a relative sense, today’s changes aren’t a big deal?

    When Richard Alley tries to explain the gravity of manmade climate change, he often invokes a particular annual phenomenon: the wildfires that blaze in the hills of Los Angeles every year. These fires are predictable, cyclical, natural. But it’d be crazy to say that, since fires are the norm, it’s fine to let arsonists set fires too. Similarly, the fact that climate has changed over millions of years doesn’t mean that manmade greenhouse gases aren’t a serious global threat.

    “Our civilization is predicated on stable climate and sea level,” says Wing, “and everything we know from the past says that when you put a lot of carbon in the atmosphere, climate and sea level change radically.”

    Since the Industrial Revolution, human activities have helped warm the globe 2 degrees F, one-quarter of what Schmidt deems an “Ice Age Unit”—the temperature change that the Earth goes through between an Ice Age and a non-Ice Age. Today’s models predict another 2 to 6 degrees Celsius of warming by 2100—at least 20 times faster than past bouts of warming over the past 2 million years.

    ______________________________________________________________
    From NASA Earth Observatory

    How is Today’s Warming Different from the Past?

    Earth has experienced climate change in the past without help from humanity. We know about past climates because of evidence left in tree rings, layers of ice in glaciers, ocean sediments, coral reefs, and layers of sedimentary rocks. For example, bubbles of air in glacial ice trap tiny samples of Earth’s atmosphere, giving scientists a history of greenhouse gases that stretches back more than 800,000 years. The chemical make-up of the ice provides clues to the average global temperature.

    See the Earth Observatory’s series Paleoclimatology for details about how scientists study past climates.

    3
    Glacial ice and air bubbles trapped in it (top) preserve an 800,000-year record of temperature & carbon dioxide. Earth has cycled between ice ages (low points, large negative anomalies) and warm interglacials (peaks). (Photograph courtesy National Snow & Ice Data Center. NASA graph by Robert Simmon, based on data from Jouzel et al., 2007.)

    Using this ancient evidence, scientists have built a record of Earth’s past climates, or “paleoclimates.” The paleoclimate record combined with global models shows past ice ages as well as periods even warmer than today. But the paleoclimate record also reveals that the current climatic warming is occurring much more rapidly than past warming events.

    As the Earth moved out of ice ages over the past million years, the global temperature rose a total of 4 to 7 degrees Celsius over about 5,000 years. In the past century alone, the temperature has climbed 0.7 degrees Celsius, roughly ten times faster than the average rate of ice-age-recovery warming.

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    Temperature histories from paleoclimate data (green line) compared to the history based on modern instruments (blue line) suggest that global temperature is warmer now than it has been in the past 1,000 years, and possibly longer. (Graph adapted from Mann et al., 2008.)

    Models predict that Earth will warm between 2 and 6 degrees Celsius in the next century. When global warming has happened at various times in the past two million years, it has taken the planet about 5,000 years to warm 5 degrees. The predicted rate of warming for the next century is at least 20 times faster. This rate of change is extremely unusual.

    See the full NASA Earth Observatory article here .
    ______________________________________________________________

    Of course there are uncertainties: “We could have a debate about whether we’re being a little too optimistic or not,” says Alley. “But not much debate about whether we’re being too scary or not.” Considering how right we were before, we should ignore history at our own peril.

    ______________________________________________________________

    See the full article here .

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    Smithsonian magazine and Smithsonian.com place a Smithsonian lens on the world, looking at the topics and subject matters researched, studied and exhibited by the Smithsonian Institution — science, history, art, popular culture and innovation — and chronicling them every day for our diverse readership.

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  • richardmitnick 6:20 pm on January 2, 2016 Permalink | Reply
    Tags: , , NASA Earth Observatory,   

    From NASA Earth: “Freeze and Thaw in the North” 

    NASA Earth Observatory

    NASA Earth Observatory

    1.2.16
    No writer credit found.

    Temp 1
    acquired March 5, 2015

    At the planet’s highest northern latitudes, nearly all of the fresh water is frozen. Even the water in the soil is locked away as ice, making it mostly inaccessible to plants. But just a short distance to the south, in the boreal areas of Alaska, Canada, Siberia, and Scandinavia, the landscape comes alive each year after the spring thaw.

    The transition is relatively rapid, occurring over just a few weeks, and coincides with increasing sunlight and spring snowmelt. Rapid warming releases liquid water. As liquid water becomes more readily available, plant and animal activity is energized. The land greens up, and animals return to graze.

    “I’m always impressed by how rapidly northern landscapes transition from frozen and dormant conditions in the winter to a rapid burst of life and activity in the spring,” said John Kimball, a scientist at the University of Montana.

    The transition between frozen and thawed land is something researchers have observed for more than 30 years with satellites. Now, NASA’s Soil Moisture Active Passive (SMAP) satellite is continuing that record.

    NASA SMAP
    NASA/SMAP

    Data from SMAP’s radar instrument were used to produce this map, which shows the freeze-thaw status of areas north of 45 degrees latitude on March 5, 2015, as spring approached. Frozen land is blue; thawed land is pink. The measurement is possible because frozen water forms crystalline structures that can be detected by satellites.

    Kimball and colleagues have mined 30 years of freeze-thaw patterns from the satellite record. In a paper published in 2012, the researchers showed that soils in the Northern Hemisphere thawed for as many as 7.5 days more in 2008 than they did in 1979. The change was primarily driven by an earlier start to the spring thaw and coincided with measureable warming in the region.

    “This was a real eye-opener to me,” Kimball said. “We found that the earlier spring-thaw was driving widespread increases in northern growing seasons.” The start and the length of the growing season have implications for how much carbon is exchanged between the land and atmosphere.

    Questions still remain. For example: How will larger areas of thaw affect carbon sources and sinks? How stable are areas of permafrost with continued global warming? But scientists are making progress. Freeze-thaw monitoring, according to Kimball, made a major advance thanks to the development of well-calibrated, long-term satellite soil moisture records. As those observations continue, and as they encompass more of the planet, it stands to reason that our understanding of the entire water cycle will improve.

    Read more in our feature story: A Little Bit of Water, A Lot of Impact.

    References and Related Reading
    Kim, Y. et al., (2012) Satellite detection of increasing Northern Hemisphere non-frozen seasons from 1979 to 2008: Implications for regional vegetation growth. Remote Sensing of Environment, 121 (2012), 472-487.
    NASA’s Jet Propulsion Laboratory (2015, March 13) Let it Go! SMAP Almost Ready to Map Frozen Soil. Accessed September 16, 2015.
    National Snow & Ice Data Center, Satellite Observations of Arctic Change. Accessed September 16, 2015.
    Natural Resources Canada (2015, September 20) Forest carbon. Accessed September 16, 2015.
    SMAP Mission Brochure (2014) Mapping Soil Moisture and Freeze/Thaw State from Space. Accessed September 16, 2015.

    NASA Earth Observatory map by Joshua Stevens, using data courtesy of JPL and the SMAP science team. Caption by Kathryn Hansen.

    See the full article here .

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
  • richardmitnick 3:10 pm on December 29, 2015 Permalink | Reply
    Tags: , , , NASA Earth Observatory,   

    From NASA Earth: “Seafloor Features Are Revealed by the Gravity Field” 

    NASA Earth Observatory

    NASA Earth Observatory

    12.29.15
    No writer credit found.

    1
    acquired 2014 (NASA Earth Observatory maps by Joshua Stevens, using data from Sandwell, D. et al. [2014]. Caption by Mike Carlowicz.)

    It has been said that we have more complete maps of the surface of Mars or the Moon than we do of Earth. Close to 70 percent of our planet is covered by water, and that water refracts, absorbs, and reflects light so well that it can only penetrate a few tens to hundreds of meters. To humans and most satellite eyes, the deep ocean is opaque.

    But there are ways to visualize what the planet looks like beneath that watery shroud. Sonar-based (sounding) instruments mounted on ships can distinguish the shape (bathymetry) of the seafloor. But such maps can only be made for places where ships and sonar pass frequently. The majority of such measurements have been made along the major shipping routes of the world, interspersed with results from scientific expeditions over the past two centuries. About 5 to 15 percent of the global ocean floor has been mapped in this way, depending on how you define “mapped.”

    There is another way to see the depths of the ocean: by measuring the shape and gravity field of Earth, a discipline known as geodesy. David Sandwell of the Scripps Institution of Oceanography and Walter Smith of the National Oceanic and Atmospheric Administration have spent much of the past 25 years negotiating with military agencies and satellite operators to allow them acquire or gain access to measurements of the Earth’s gravity field and sea surface heights. The result of their collaborative efforts is a global data set that tells where the ridges and valleys are by showing where the planet’s gravity field varies.

    The map above shows a global view of gravity anomalies, as measured and assembled by Sandwell, Smith, and colleagues. Shades of orange and red represent areas where seafloor gravity is stronger (in milligals) than the global average, a phenomenon that mostly coincides with the location of underwater ridges, seamounts, and the edges of Earth’s tectonic plates. Shades of blue represent areas of lower gravity, corresponding largely with the deepest troughs in the ocean. The second map shows a tighter view of that data along the Mid-Atlantic Ridge between Africa and South America.

    Temp 1
    acquired 2014

    The maps were created through computer analysis and modeling of new satellite altimetry data from the European Space Agency’s CryoSat-2 and from the NASA-CNES Jason-1 (see at the end of this post), as well as older data from missions flown in the 1980s and 90s. CryoSat-2 was designed to collect data over Earth’s polar regions, but it also collected measurements over the oceans. Jason-1 was specifically designed to measure the height of the oceans, but it had to be adjusted to a slightly different orbit in order to acquire the data needed to see gravity anomalies.

    ESA CryoSat 2
    ESA/Cryosat 2

    But how does the height of the sea surface (which is what the altimeters measured) tell us something about gravity and the seafloor? Mountains and other seafloor features have a lot of mass, so they exert a gravitational pull on the water above and around them; essentially, seamounts pull more water toward their center of mass. This causes water to pile up in small but measurable bumps on the sea surface. (If you are wondering why a greater mass would not pull the water down, it is because water is incompressible; that is, it will not shrink into a smaller volume.)

    The new measurements of these tiny bumps on the sea surface were compared and combined with previous gravity measurements to make a map that is two- to four times more detailed than before. Through their work, Sandwell, Smith, and the team have charted thousands of previously uncharted mountains and abyssal hills. The new map gives an accurate picture of seafloor topography at a scale of 5 kilometers per pixel.

    Temp 2
    acquired 2014

    From these seafloor maps, scientists can further refine their understand of the evolution and motion of Earth’s tectonic plates and the continents they carry.

    4
    The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, which float on the fluid-like (visco-elastic solid) asthenosphere. The relative fluidity of the asthenosphere allows the tectonic plates to undergo motion in different directions. This map shows 15 of the largest plates. Note that the Indo-Australian Plate may be breaking apart into the Indian and Australian plates, which are shown separately on this map.

    They can also improve estimates of the depth of the seafloor in various regions and target new sonar surveys to further refine the details, especially in areas where there is thick sediment. This third map shows the gravity data as a cartographer would represent the seafloor, with darker blues representing deeper areas.

    References and Related Reading
    Sandwell, D. et al. (2014) New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure. Science, 346 (6205), 65–67.
    Scripps Institution of Oceanography (2014, October 2) Marine Gravity from Satellite Altimetry. Accessed December 23, 2015.
    Scripps Institution of Oceanography (2014, October 2) New Map Exposes Previously Unseen Details of Seafloor. Accessed December 23, 2015.
    Carlowicz, M. (1995, October 31) New Map of Seafloor Mirrors Surface. EOS, Transactions, AGU, 441–442.
    University of Sydney (2014, October 5) Mapping the Seafloor from Space. Accessed December 23, 2015.
    Scientific American (2014, October 9) Just How Little Do We Know about the Ocean Floor? Accessed December 23, 2015.
    Schmidt Ocean Institute (2013, March 12) The Ocean: Haven’t We Already Mapped It? Accessed December 23, 2015.
    NOAA National Ocean Service (2015) What is geodesy? Accessed December 23, 2015.
    NOAA National Ocean Service (2015) How much of the ocean have we explored? Accessed December 23, 2015.

    NASA Earth Observatory maps by Joshua Stevens, using data from Sandwell, D. et al. (2014). Caption by Mike Carlowicz.

    Instrument(s):
    Model
    JASON-1

    NASA Jason-1
    NASA/JPL JASON-1

    See the full article here .

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
  • richardmitnick 5:07 pm on November 29, 2015 Permalink | Reply
    Tags: , , NASA Earth Observatory,   

    From NASA Earth: A New Island 

    NASA Earth Observatory

    NASA Earth Observatory

    11.25.15

    1
    acquired November 6, 2013

    2
    acquired October 11, 2015

    Two years ago, a new island, or “nijima,” rose above the water line in the western Pacific, about 1,000 kilometers (600 miles) south of Tokyo. It grew out of the sea just 500 meters from Nishinoshima, another volcanic island. Over the past two years, that new island swallowed up its neighbor, and the merged island is now twelve times the size of the old island.

    The Operational Land Imager (OLI) on Landsat 8 captured these images of the old and new Nishinoshima.

    NASA Landsat 8 OLI
    OLI

    NASA LandSat 8
    Landsat 8

    The top image shows the area on November 6, 2013, two weeks before the eruption started. The second image was acquired on October 11, 2015, the most recent cloud-free view. In both images, pale areas just offshore likely reveal volcanic gases bubbling up from submerged vents or sediments disturbed by the eruption. Turn on the image comparison tool to see the transformation.

    Nishinoshima is part of the Ogasawara Islands, in the Volcano Islands arc.

    3
    The Ogasawara Islands, consisting of the Mukojima, Chichijima, and Hahajima island groups, are located far south of the Japanese home islands.

    It is located at 27°14’ North latitude and 140°52’ East longitude, about 130 kilometers (80 miles) from the nearest inhabited island. According to the Japanese coast guard, which surveyed the island on November 17, the island now stretches 1.9 kilometers from east to west and 1.95 kilometers from north to south. It stands about 100 meters above the sea surface.

    Lava continues to ooze out slowly, though there are occasional explosions of rock and ash as well. Investigators noted that the total surface area of the island decreased a bit from September to November 2015—2.67 square kilometers to 2.64—likely because of erosion of the coasts by wave action.

    You can see the evolution of the volcanic island by visiting out natural hazards event page.

    See the full article here .

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
  • richardmitnick 1:05 pm on October 13, 2015 Permalink | Reply
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    From NASA Earth: “El Niño Strengthening” 

    NASA Earth Observatory

    NASA Earth Observatory

    1
    acquired October 5, 1997 – October 4, 2015

    The latest analyses from the National Oceanic and Atmospheric Administration and from NASA confirm that El Niño is strengthening and it looks a lot like the strong event that occurred in 1997–98. Observations of sea surface heights and temperatures, as well as wind patterns, show surface waters cooling off in the Western Pacific and warming significantly in the tropical Eastern Pacific.

    “Whether El Niño gets slightly stronger or a little weaker is not statistically significant now. This baby is too big to fail,” said Bill Patzert, a climatologist at NASA’s Jet Propulsion Laboratory. October sea level height anomalies show that 2015 is as big or bigger in heat content than 1997. “Over North America, this winter will definitely not be normal. However, the climatic events of the past decade make ‘normal’ difficult to define.”

    The maps above show a comparison of sea surface heights in the Pacific Ocean as observed at the beginning of October in 1997 and 2015. The measurements come from altimeters on the TOPEX/Poseidon mission (left) and Jason-2 (right); both show averaged sea surface height anomalies. Shades of red indicate where the ocean stood higher (in tens of millimeters) than the normal sea level because warmer water expands to fill more volume. Shades of blue show where sea level and temperatures were lower than average (contraction). Normal sea-level conditions appear in white.

    “The trade winds have been weakening again,” Patzert said. “This should strengthen this El Niño.” Weaker trade winds out of the eastern Pacific allow west wind bursts to push warm surface waters from the central and western Pacific toward the Americas. Click here [in the full article] to watch a video of Kelvin waves propagating across the ocean in the first seven months of 2015.

    In its October monthly update, scientists at NOAA’s Climate Prediction Center stated: “All multi-model averages predict a peak in late fall/early winter. The forecaster consensus unanimously favors a strong El Niño…Overall, there is an approximately 95 percent chance that El Niño will continue through Northern Hemisphere winter 2015–16.”

    2

    The July–September average of sea surface temperatures was 1.5°C above normal, NOAA reported, ranking third behind 1982 (1.6°C) and 1997 (1.7°C). The plot above shows sea surface temperatures in the tropical Pacific for all moderate to strong El Niño years since 1950.

    Both Patzert and NOAA forecasters believe the southern tier of North America, particularly southern California, is likely to see a cooler and wetter than normal winter, while the northern tier could be warmer and drier. But the sample of El Niños in the meteorological record are still too few and other elements of our changing climate are too new to say with certainty what the winter will bring.

    NASA Earth Observatory map by Jesse Allen, using Jason-2 and TOPEX/Posideon data provided by Akiko Kayashi and Bill Patzert, NASA/JPL Ocean Surface Topography Team. NASA Earth Observatory chart by Joshua Stevens, using data from NOAA. Caption by Mike Carlowicz.

    NASA Jason 2
    NASA/Jason-2

    NASA Topex Poseiden
    NASA TOPEX/Poseodon

    Instrument(s):
    TOPEX/Poseidon
    JASON-2

    See the original article for further reading references.

    See the full article here .

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
  • richardmitnick 11:01 am on October 11, 2015 Permalink | Reply
    Tags: , , , NASA Earth Observatory, NASA Landsat 8   

    From NASA Earth: “Malaspina Glacier, Alaska” 

    NASA Earth Observatory

    NASA Earth Observatory

    1
    acquired September 24, 2014

    The ice of a piedmont glacier spills from a steep valley onto a relatively flat plain, where it spreads out unconstrained like pancake batter. Elephant Foot Glacier in northeastern Greenland is an excellent example; it is particularly noted for its symmetry. But the largest piedmont glacier in North America (and possibly the world) is Malaspina in southeastern Alaska.

    On September 24, 2014, the Operational Land Imager (OLI) on Landsat 8 acquired this image of Malaspina Glacier.

    NASA Landsat 8 OLI
    OLI

    NASA LandSat 8
    NASA LandSat 8

    The main source of ice comes from Seward Glacier, located at the top-center of this image. The Agassiz and Libbey glaciers are visible on the left side, and the Hayden and Marvine glaciers are on the right.

    The brown lines on the ice are moraines—areas where soil, rock, and other debris have been scraped up by the glacier and deposited at its sides. Where two glaciers flow together, the moraines merge to form a medial moraine. Glaciers that flow at a steady speed tend to have moraines that are relatively straight.

    But what causes the dizzying pattern of curves, zigzags, and loops of Malaspina’s moraines? Glaciers in this area of Alaska periodically “surge,”meaning they lurch forward quickly for one to several years. As a result of this irregular flow, the moraines at the edges and between glaciers can become folded, compressed, and sheared to form the characteristic loops seen on Malaspina. For instance, a surge in 1986 displaced moraines on the east side of Malaspina by as much as 5 kilometers (3 miles).

    See the full article for the list of references with links.

    See the full article here .

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
  • richardmitnick 12:46 pm on October 3, 2015 Permalink | Reply
    Tags: , , NASA Earth Observatory,   

    From NASA Earth: “Some Insight on the Color of the Ocean” 

    NASA Earth Observatory

    NASA Earth Observatory

    September 28th, 2015
    Mike Carlowicz

    For nearly 20 years, Jim Acker, a contract support scientist at the NASA Goddard Earth Science Data and Information Services Center (GES DISC), has helped oceanographers compile and study data collected by satellites. A chemical oceanographer by training, he has been involved in the study of ocean color as viewed from space. He recently wrote a book for NASA about the history of the subject. He is also scheduled to deliver the NASA Goddard Science Colloquium on September 30 at 3:30 p.m. His talk is entitled: Rise of the Machines: Computational Power and the History of NASA’s Ocean Color Missions. He gave us a preview of the book and the talk this week.

    NASA Earth Observatory: Most of us think of the ocean as blue; in some places, it looks green. So what do scientists mean when they refer to “ocean color?”

    1

    Jim Acker: Well, it’s blue and green and brown, and occasionally a few other related hues. Ocean color refers to the science of using satellite sensors to measure the light emanating from the ocean and determining what is in the water based on those light measurements. The main things that change the color of the ocean are phytoplankton—the floating plants at the base of the ocean food chain—dissolved colored substances, and different kinds of sediments.

    EO: What are some of the things we have learned by looking at the ocean from satellites?

    Acker: One of the main things done with global observations has been estimating how much carbon is produced by the growth of phytoplankton. Ocean color observations have shown how much this can vary, particularly with events like El Niño or La Niña in the Pacific Ocean.

    The satellite view also can show how much variation there is over relatively short distances. A ship could be sitting in nice clear water, and just a few tens of kilometers away there could be a strong phytoplankton bloom that they would never know about without observations from space.

    2

    The observations also have helped understand phytoplankton patterns in hard-to-reach places like the polar seas and the Red Sea or Arabian Sea. The interaction of the land and ocean, with weather patterns and river inflows, has also been better observed.

    EO: Have there been any big surprises?

    Acker: Definitely. One of the biggest surprises from the Coastal Zone Color Scanner, the first NASA ocean color mission, was truly how much the ocean varied over small distances. Where oceanographers used to draw simple lines, they realized there were swirls and spirals and curlicues and loops and jets and rings. It was much more complicated.

    Another surprise when SeaWiFS and MODIS started making global observations was how cloudy it is over the oceans.

    NASA SeaWiFS
    SeaWiFS

    NASA AQUA MODIS
    MODIS

    It takes really impressive data processing to get accurate values because of that.

    4

    And because the satellites make continuous observations, they have observed many different features that weren’t where we expected them to be or they happened more often than we thought.

    EO: What provoked you to write a book?

    Acker: NASA wanted to have some histories of NASA science, and I wanted to tell the history of ocean color because it’s been so successful. It’s like a well-trained, elite athlete: they make what they do look easy, though a lot of hard effort and training makes that possible.

    5

    Ocean color measurements are very difficult to make, but because the missions have been so successful, the public and even most scientists have just seen the beautiful results and have not realized the dedicated, behind-the-scenes work that made them possible. It isn’t just about seeing images from space on a computer monitor. To be sure the data is accurate, there have been some true high-seas adventures. I was able to get a lot of real-life experiences from the scientists and engineers into the book.

    EO: What is your favorite book about science? And your favorite writer?

    Acker: My favorite book that was sort of about science was The Map that Changed the World by Simon Winchester; I also enjoyed his book about the eruption of Krakatoa. My favorite writers are Pat Conroy and J.R.R. Tolkien. The late Stephen Jay Gould wrote a lot of things about science I liked. And I have to mention that I just read Andy Weir’s The Martian and was quite impressed. I’m looking forward to seeing the movie.

    See the full article here .

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
  • richardmitnick 12:15 pm on September 27, 2015 Permalink | Reply
    Tags: , , Indonesia fires, NASA Earth Observatory   

    From NASA Earth: “Smoke Blankets Indonesia” 

    NASA Earth Observatory

    NASA Earth Observatory

    1
    2
    acquired September 24, 2015

    Fires in Indonesia are not like most other fires. They are extremely difficult to extinguish. They smolder under the surface for long periods, often for months. Usually, firefighters can only put them out with the help of downpours during the rainy season. And they release far more smoke and air pollution than most other types of fires.

    The root cause is large deposits of peat—a soil-like mixture of partly decayed plant material formed in wetlands—lining the coasts of Borneo and Sumatra. Peat fires start to burn in Indonesia every year because farmers engage in “slash and burn agriculture,” a technique that involves frequent burning of rainforest to clear the way for crops or grazing animals. In Indonesia, the intent is often to make room for new plantings of oil palm and acacia pulp.

    “Most burning starts on idle, already-cleared peatlands and escapes underground into an endless source of fuel,” explained David Gaveau of the Center for International Forestry Research.

    As seen in this September 24 image from the <a href="http://“>Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, 2015 is no exception.

    NASA AQUA MODIS
    MODIS on Terra

    NASA Terra satellite
    NASA/Terra

    Red outlines indicate hot spots where the sensor detected unusually warm surface temperatures associated with fires. Thick gray smoke hovers over both islands and has triggered air quality alerts and health warnings in Indonesia and neighboring countries. Visibility has plummeted.

    Scientists monitoring the fires are concerned that the problem will get worse before it gets better. That’s because strong El Niños, like the one currently brewing in the Pacific, lengthen the dry season and reduce the amount of rainfall. During a strong El Niño in 1997, the lack of rain allowed fires to burn out of control on a wide scale, releasing record levels of air pollution and greenhouse gases.

    “We are on a similar trajectory to other bad years,” said Robert Field, a Columbia University scientist based at NASA’s Goddard Institute for Space Studies. “Conditions in Singapore and southeastern Sumatra are tracking close to 1997, with some stations having visibility less than 1 kilometer (0.6 miles) on average for a week. In Kalimantan, there have been reports of visibility less than 50 meters (165 feet).”

    Aerosol optical depth data (collected by MODIS) show particle levels similar to the peak in 2006, the last major burning event. This time, however, the high levels are occurring several weeks earlier. “If the forecasts for a longer dry season hold,” said Field, “this suggests 2015 will rank among the most severe events on record,”

    Vrije Universiteit Amsterdam scientist Guido van der Werf has been monitoring the number and size of the Indonesian fires with MODIS. “There are more and larger fires this year. We are on a track above any other year since 2001, when MODIS observations became available,” he said. “And we are only halfway through the fire season.”

    Along with colleagues at NASA and the University of California, Irvine, van der Werf has developed a technique to estimate the amount of trace gases and airborne particles that fires emit—many of them pollutants—based on satellite observations of fires and vegetation cover. The project, known as the Global Fire Emissions Database (GFED), produces both regional and global estimates of fire emissions based on data from 1997 to the present. According to the GFED analysis, the 2015 Indonesia fires have released greenhouse gases equivalent to about 600 million tons through September 22, a number that rivals carbon dioxide a year of carbon emissions from Germany.

    References
    The Conversation (2015, June 16) Indonesia at risk from huge fires because of El Nino. Accessed September 24, 2015.
    Field, R. (2009, February 22) Human amplification of drought-induced biomass burning in Indonesia since 1960. Nature Geoscience, 6112.
    Gaveau, D. (2014, May 7) Major atmospheric emissions from peat fires in Southeast Asia during non-drought years: evidence from the 2013 Sumatran fires. Scientific Reports, 6112.
    International Business Times (2015, September 24) Singapore Blanketed In Haze Blown In From Indonesia, Conditions Expected To Worsen. Accessed September 24, 2015.
    Turetsky et al, (2015) Global vulnerability of peatlands to fire and carbon loss. Nature Geoscience, 2, 185-189.
    Straits Times (2015, September 24) Indonesia declares emergency in haze-hit province. Accessed September 24, 2015.
    Wildfire Magazine (2014, May 7) The long slow burn of smoldering peat mega-fires. Accessed September 24, 2015.
    World Resources Institute (2014, April 3) Preventing Forest Fires in Indonesia: Focus on Riau Province, Peatland, and Illegal Burning. Accessed September 24, 2015.

    NASA image by Adam Voiland (NASA Earth Observatory) and Jeff Schmaltz (LANCE MODIS Rapid Response). Caption by Adam Voiland.

    See the full article here .

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
  • richardmitnick 4:51 pm on September 20, 2015 Permalink | Reply
    Tags: , NASA AQUA, NASA Earth Observatory   

    From NASA Earth: “Snow in the Andes” 

    NASA Earth Observatory

    NASA Earth Observatory

    9.20.15

    1
    acquired September 12, 2015

    As the end of Southern Hemisphere winter approached, snow painted the region’s mountain ranges. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this image of the snowy Andes Mountains on September 12, 2015.

    NASA AQUA MODIS
    MODIS

    NASA Aqua satellite
    AQUA

    The Andes—the longest series of mountain ranges the world—span about 7,242 kilometers (4,500 miles) and runs through seven countries. The segment visible in the image above shows about 1,200 kilometers (750 miles) of the range in Chile and Argentina. View the large image to see an even broader area.

    The political boundary between Chile and Argentina runs through the rugged mountain terrain. Aconcagua, the highest mountain in the Southern Hemisphere, is visible just east of the border, in Argentina. The peak rises 6,962 meters (22,841 feet) above sea level.

    The 2015 winter season began with little precipitation, compounding the effects of a multi-year drought in and around Santiago. In mid-July, however, a large storm dumped as much as 3 meters (10 feet) of snow in the mountains northeast of the city. Smaller accumulations were recorded elsewhere in the range.

    The snowpack that accumulates in the mountains each winter is the primary source of water for communities at lower altitudes. Streams deliver the melt water to populated areas of central-western Argentina and central Chile, where it is particularly important for cities’ water supply, power generation, and agriculture. However, according to a report by the Intergovernmental Panel on Climate Change, frozen areas in the Andes are generally retreating, and runoff in the vicinity of Chile and Argentina is decreasing.

    See the full article here .

    Please help promote STEM in your local schools.

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
  • richardmitnick 1:18 pm on September 13, 2015 Permalink | Reply
    Tags: , , NASA Earth Observatory   

    From NASA Earth: “Partial Opening of the Northwest Passage” 

    NASA Earth Observatory

    NASA Earth Observatory

    Temp 1
    acquired August 31, 2015

    2
    acquired August 31, 2015

    There was a time when the Northwest Passage was a sort of maritime Holy Grail, a route so desired and sought after, but so elusive. For most of the recorded history of North America, the Passage has been nearly impassable and often deadly. But with the modernization of ships and the warming of the Earth, cruising and sailing through the Canadian Archipelago from Baffin Bay to the Beaufort Sea has grown more common and easier. But it’s not necessarily easy.

    The top image above shows the Northwest Passage as it appeared on August 31, 2015, to the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi-NPP satellite. The second image was acquired the same day by the Operational Land Imager (OLI) on Landsat 8. The white box on the top image shows the area depicted in the Landsat view. Both images are natural color. Note that much of the white covering the Northwest Passage in the VIIRS image is cloud cover, not sea ice.

    NASA VIIRS
    VIIRS

    NASA Suomi NPP
    Suomi-NPP

    NASA Landsat 8 OLI
    OLI on Landsat 8

    NASA LandSat 8
    Landsat 8

    The Northwest Passage is a complex, winding maze of sounds, channels, bays, and straits that pass through often ice-choked Arctic waters. Mariners refer to two main routes: a southern passage and a northern passage.

    The southern route generally follows the one taken by Roald Amundsen from 1903–1906, when his crew completed the first successful transit through the region. The southern passage goes south of Prince of Wales Island and Victoria Island (and sometimes King William Island) and enters the Beaufort Sea south of Banks Island. It includes several narrow and shallow waterways that are better suited to small ships than large commercial vessels. This southern or “Amundsen” passage has been open for several weeks in the summer of 2015.

    The northern passage runs through Lancaster Sound, Parry Channel, and McClure Strait—waterways that are wider, deeper, and more suited to large ships. In the satellite images above, the Parry Channel is filled with a melange of sea ice, though it does not appear to be completely frozen over. According to an August 31 analysis by the Multisensor Analyzed Sea Ice Extent (MASIE) product (created by the U.S. National Ice Center and posted by the National Snow and Ice Data Center) the northern route was considered mostly ice-filled for the sake of navigation. See the MASIE map below.

    3

    As NASA ice scientists Walt Meier and Claire Parkison note, the opening of the Northwest Passage is not that unusual anymore, particularly along the southern route. However, with the warming of the Arctic and the shrinking of sea ice in the past three decades, the southern passage is now open more often and for longer stretches of each summer. According to Canadian government sources, as many as 30 passages were made as recently as 2012. The number of ships crossing the Northwest Passage has been steadily growing since the 1980s.

    But even as Arctic sea ice declines, the opening of the Northwest Passage is not necessarily a sure bet in any given year. “The Northwest Passage does not always correlate with the overall sea ice because it is dependent to some degree on ice drifting into and out of the channels,” Meier said. “You can have a relatively high ice year overall when the passage clears out, and you can have a relatively low ice year—like this year—when the passage still has ice. There is less ice in recent years than there used to be and the passages are more easily navigable than they used to be, but specific conditions from year to year can vary substantially.”

    A new paper [link not found]published in Geophysical Research Letters notes that a warm and mostly ice-free Arctic will not necessarily mean smooth sailing through the Northwest Passage any time soon. The ice that forms in these channels and bays is often some of the thickest in all of the Arctic. That makes it more likely to survive through the summer at a thickness that could harm ships.

    Related Reading
    Haas, C., and Howell, S.E.L. (2015) Ice thickness in the Northwest Passage. Geophysical Research Letters, 42.
    National Snow and Ice Data Center (2015, September 2) Arctic Sea Ice News and Analysis: Steady decline, seasonal minimum approaching. Accessed September 11, 2015.
    Northwest Passage 2015 (2015) Northwest Passage Ice Maps. Accessed September 11, 2015.
    Northwest Territories (Canada) Environment and Natural Resources (2015) Trends in shipping in the Northwest Passage and the Beaufort Sea. Accessed September 11, 2015.
    The Washington Post (2015, September 10) The Arctic is melting—but getting ships through the Northwest Passage is another story. Accessed September 11, 2015.

    NASA Earth Observatory images by Jesse Allen, using VIIRS data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Landsat data from the U.S. Geological Survey. Multisensor Analyzed Sea Ice Extent (MASIE) data courtesy of teh National Snow and Ice Data Center. Caption by Mike Carlowicz.

    Instrument(s):
    Suomi NPP – VIIRS
    Landsat 8 – OLI

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    The Earth Observatory’s mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models. The Earth Observatory staff is supported by the Climate and Radiation Laboratory, and the Hydrospheric and Biospheric Sciences Laboratory located at NASA Goddard Space Flight Center.

     
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