The climate monitoring 'A-Train'

Not to be confused with the “A-Team” of climate scientists, NASA/Goddard Space Flight Center announces:

Introducing the ‘A-Train’

artists concept of the A-Train with labels Artist’s Concept of the A-Train constellation of satellites. Credit: NASA

Mention the “A-Train” and most people probably think of the jazz legend Billy Strayhorn or perhaps New York City subway trains — not climate change. However, it turns out that a convoy of “A-Train” satellites has emerged as one of the most powerful tools scientists have for understanding our planet’s changing climate.

The formation of satellites — which currently includes Aqua, CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and Aura satellites — barrels across the equator each day at around 1:30 p.m. local time each afternoon, giving the constellation its name; the “A” stands for “afternoon.”

Together, these four satellites contain 15 separate scientific instruments that observe the same path of Earth’s atmosphere and surface at a broad swath of wavelengths. At the front of the train, Aqua carries instruments that produce measurements of temperature, water vapor, and rainfall. Next in line, CloudSat, a cooperative effort between NASA and the Canadian Space Agency (CSA), and CALIPSO, a joint effort of the French space agency Centre National d’Etudes Spatiales (CNES) and NASA, have high-tech laser and radar instruments that offer three-dimensional views of clouds and airborne particles called aerosols. And the caboose, Aura, has a suite of instruments that produce high-resolution vertical maps of greenhouse gases, among many other atmospheric constituents.

In coming months, the A-Train will expand with the launch of NASA’s aerosol-sensing Glory satellite and the carbon-tracking Orbiting Carbon Observatory 2 (OCO-2) satellite. In 2010, the Japan Aerospace Exploration Agency (JAXA) plans to launch the Global Change Observation Mission-Water (GCOM-W1), which will monitor ocean circulation. Meanwhile, a fifth satellite, France’s Polarization and Anistropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar (PARASOL), which studies aerosols, is easing out of an A-Train orbit as its fuel supplies dwindles.

Accidental Origins

This multi-sensor view allows scientists to simultaneously observe changes in key environmental phenomenon – such as clouds or ice sheets – from numerous perspectives. And it helps skirt around engineering obstacles that would have made it impossible to cluster all 15 instruments on one large spacecraft.

But it wasn’t necessarily planned that way. Formation flying is a fairly novel concept, and it came to the fore partly by accident. The concept of an A-Train first emerged when scientists and engineers were hashing out the orbit of Aura, which launched in 2004. At the time, rather than calculating a whole new orbital plan for Aura, flight engineers realized they could simply model its orbit after Aqua, a sister satellite NASA had launched in 2002.

They went forward with that plan, but limitations in data transmissions rates, meant that the two satellites ended up flying much closer to each other than originally planned. In the end, they decided that Aura would fly about 6,300 kilometers – a mere 15 minutes of flight – behind Aqua.

Meanwhile, two additional satellites that study minute airborne particles called aerosols and clouds – the CALIPSO and CloudSat – without realizing it had requested nearly identical orbits near Aura because the scientists involved with these missions wanted to compare their results with the humidity and cloud measurements coming from Aura. In 2006, CloudSat and CALIPSO eased into the train behind Aura just 93 kilometers – about 12.5 seconds – from one another. As a result, CALIPSO’s lidar beam and CloudSat’s radar have coincided at Earth’s surface about ninety percent of the time they have been in orbit.

Reaping the Rewards

The longer the A-Train has existed, the more scientists have begun to appreciate its potential. Indeed, scientists representing all the A-Train satellites are meeting this week in New Orleans to compare notes and to sketch out plans for future cross-satellite collaboration. Leading earth scientists from three national space agencies, including the director of NASA’s Earth Science Division Michael Freilich, Didier Renaut from CNES and Haruhisa Shimoda of JAXA, are giving talks about A-Train science. And scientists from dozens of institutions are presenting research on topics ranging from air quality, to the carbon cycle, to cloud dynamics.

There is a great deal to discuss. Multi-sensor measurements from the A-Train, for example, have proven critical in working out why the summer of 2007 experienced the greatest loss of Arctic sea ice in history. A-Train sensors captured environmental conditions during the loss – which was far greater than climate models had predicted – allowing scientists to go back after the fact to pinpoint its causes. By now, they have proven that some unexpected factors, such as anomalously high winds and an sharp decrease in cloudiness, fueled the rapid loss, in addition to more predictable culprits such as high air temperatures and low humidity.

Likewise, synergistic A-Train measurements have yielded great insight into aerosols – small airborne particles such as dust, sea salt, and soot. Depending on their composition, aerosols can scatter and or absorb the sun’s heat, and can thus both warm and cool the planet. Some types of aerosols also seed clouds, A-Train sensors have helped reveal, and can change cloud behavior. A-Train instruments aboard Aura and Aqua, for example, produced groundbreaking insight about aerosols and ice clouds, making it possible for scientists to prove that polluted ice clouds have smaller particles and are therefore much less likely to produce rain.

Still, pressing questions about our climate remain. What is the overall affect of aerosols and clouds on climate? How much carbon is absorbed by forests? How will the monsoon cycle react to a warming world? To what extent will a changing climate change the size and strength of hurricanes? And what feedback cycles will encourage or discourage climate change? These and many more questions still need answers, and now that the power of formation flying is clear, it is a good bet that A-Train satellites will play a key role in answering them.

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Written by:

Adam Voiland

NASA’s Earth Science News Team

http://www.nasa.gov/mission_pages/a-train/a-train.html#

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38 thoughts on “The climate monitoring 'A-Train'

  1. Will the “scientists” change or “hide the decline” of the raw satellite data to suit their “consensus” models/settled science/public policies?

  2. Questions raised…Still, pressing questions about our climate remain. What is the overall affect of aerosols and clouds on climate? How much carbon is absorbed by forests? How will the monsoon cycle react to a warming world? To what extent will a changing climate change the size and strength of hurricanes? And what feedback cycles will encourage or discourage climate change?
    Don’t we have enough data in the can to answer at least some of these questions?
    What is the overall affect of aerosols and clouds on climate? Hasn’t this been studied?
    How much carbon is absorbed by forests? Weigh some trees.
    How will the monsoon cycle react to a warming world? Look at how the monsoon cycle reacted to two warming periods during the last century. Ditto for “To what extent will a changing climate change the size and strength of hurricanes?”
    It seems to me that we need more studies because they don’t like the answers available from current data, not becasue there are no answers to be had.

  3. “In coming months, the A-Train will expand with the launch of NASA’s aerosol-sensing Glory satellite”
    I read this article quickly and this sentence really made me laugh

  4. Thanks. Fascinating. Will the cloud observations give an answer to the proposed link to G.Cosmic Rays? When can one expect results and conclusions to be available?

  5. I just finished reading the post and comments about the planet saving possibility via reducing my number of e-mails. Now I read of multiple satellites and rocket launches. This makes we wonder:
    How many e-mails equal one rocket launch?
    One air plane flight from New York to Sydney?
    One ice core drilled in Greenland?
    One circumnavigation of the Arctic Ocean followed by a Canadian Icebreaker. One shipment of beer from the craft brewer to my refrigerator . . . Wait a minute!

  6. “There is a great deal to discuss. Multi-sensor measurements from the A-Train, for example, have proven critical in working out why the summer of 2007 experienced the greatest loss of Arctic sea ice in history. A-Train sensors captured environmental conditions during the loss – which was far greater than climate models had predicted – allowing scientists to go back after the fact to pinpoint its causes. By now, they have proven that some unexpected factors, such as anomalously high winds and an sharp decrease in cloudiness, fueled the rapid loss, in addition to more predictable culprits such as high air temperatures and low humidity.”
    #
    To bad all of this wonderful instrumentation is being to be used to give a patina of science to propaganda.

  7. I hope these satellites can be used to identify how the troposphere is cooled by radiation escaping from this part of the atmosphere. I have seen a lot of speculation on this subject and generated some of my own.
    To the best of my knowledge, all we see is heat being convected upward with no real good explanation of how that heat is converted to radiation that escapes to outer space. There is no substitute for real data. As long as we do not appear to know the spectrum of this non-surface, atmospheric radiation, I do not think we can assess the impact of CO2 on the convective cooling.

  8. If it is trying to predict what is going to happen in the future you are after, a crystal ball would be a whole lot cheaper. And every bit as effective.
    In reality, there is nothing humans can do which would make the slightest difference. “Climate” is a complete misnomer used as “global climate”. Climates are all of a local nature, and are a compendium of the kind of weather and temperatures that have occurred in the past within a given area. Variances from “averages” can be and are substantial. Even knowing a whole lot more about what is happening right now will not allow humans to control weather in the future, and certainly not predict future weather events.
    Earth movements and volcanic events were rather mild in the 20th Century, as compared with a good many previous centuries. That it was a rare warm period was wonderful for civilization. The dawning of the Petroleum Age , circa 1850, was the beginning of a “golden age” for humans, and allowed for far greater food production (and a good many other things beneficial to humans), as has the increased levels of CO2 in the atmosphere. There is no technology in sight which can actually replace natural gas, coal and petroleum that would come even close to meeting the needs of the present human population of Earth.
    Natural forces rule, and always will rule. All that we are doing with present western culture government policies is making humans live more miserable lives, which will all end in any event.
    The seismic activity of the planet is getting far more active, again. The future looks as if it might become very interesting . . . and deadly to all life forms.
    What I read as of now is that there is a serious world food shortage, and much of this shortage seems to be caused by using productive agricultural land for the purpose of making ethanol instead of for food production, which is, in my opinion, complete absurdity.
    The entire world, it seems to me, has gone quite mad. We are destroying ourselves with our foolishness.

  9. LarryOldtimer says:
    October 27, 2010 at 9:51 am
    The entire world, it seems to me, has gone quite mad. We are destroying ourselves with our foolishness.
    What you say isperhaps correct for the US and some European countries. Don’ t think you can generalize it, believe me, YOU ARE in troubles, we are not.
    The occidental world’s original sin was “agnosticism”.

  10. All that expensive hardware whizzing around in orbit, measuring climate stuff, and the climate alarmists still can’t get it right…

  11. John from CA
    What about the 18.0 degrees on the North east coast of Greenland that is covered by ice? It appears that someone is letting all of those anomolous tempetures that they use to jack up the AGW to show up on their output again. Someone’s head must roll.

  12. #
    LarryOldtimer says:
    October 27, 2010 at 9:51 am
    If it is trying to predict what is going to happen in the future you are after, a crystal ball would be a whole lot cheaper. And every bit as effective.
    ——————————
    But not a cool as satellites. Disclaimer … I used to work in the space industry when NASA still did science. BTW, the post you commented on before was sarcasm 😛 We should have been on the moon 20 years ago!
    #
    That it was a rare warm period was wonderful for civilization. The dawning of the Petroleum Age , circa 1850, was the beginning of a “golden age” for humans, and allowed for far greater food production …
    ————————————-
    Technically, we are still in an ice-age. A few more degrees C would do wonders for civilization. As far as golden-age … to realy get things going, we need to put the statist back in their boxes which is something that sometimes goes hand-in-hand with improving weather.
    #
    Natural forces rule, and always will rule.
    ——————————
    And even if man had any significant impact, we are part of nature 😀
    #
    All that we are doing with present western culture government policies is making humans live more miserable lives, which will all end in any event.
    —————————–
    I think this is the objective of the statist 🙁

  13. Glen says:
    October 27, 2010 at 11:21 am
    John from CA
    What about the 18.0 degrees on the North east coast of Greenland that is covered by ice? It appears that someone is letting all of those anomolous tempetures that they use to jack up the AGW to show up on their output again. Someone’s head must roll.
    =====
    I’m not sure whats up with Sailwx. They are also showing ships in the ice fields along the Northern coast of Greenland.
    http://sailwx.info/shiptrack/shiplocations.phtml?lat=78.9&lon=10.3&radius=925

  14. old44 says:
    October 27, 2010 at 12:09 pm
    Which one stops the manipulation of data after it has been received.
    #
    That would be the WUWT satellite.

  15. The problem with using these satellites for climate observation is that they are in earth orbit. While the close correlation in their observing times does provide advantages, they are still extrapolating to the whole earth from what they scan from a strip. The one space craft that really needs to be launched is DSCOVR. This is still sitting on the ground instead of in the L1 position between Earth and the Sun. However as the results from DSCOVR are likely to confirm Dr. Spencers work, I question how much political will there is to launch the climate observatory.

  16. “Still, pressing questions about our climate remain. What is the overall affect of aerosols and clouds on climate? How much carbon is absorbed by forests? How will the monsoon cycle react to a warming world? To what extent will a changing climate change the size and strength of hurricanes? And what feedback cycles will encourage or discourage climate change? These and many more questions still need answers, and now that the power of formation flying is clear, it is a good bet that A-Train satellites will play a key role in answering them.
    Just shows how little we really know… and I thought the science was settled!!!

  17. So basically what is going on is that another technological “choke point” is being created so that a James Hanson or another Phil Jones can connive another “successful Psuedo-Scientific Fraud.” Is that it? Is that what I’m reading?

  18. CloudSat Payload: “The spacecraft payload consists of a millimeter-wave radar.”
    The CALIPSO payload: “the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), the Imaging Infrared Radiometer (IIR), and the Wide Field Camera (WFC).”
    NASA claims it is studying earth’s weather and climate systems but has not put instrumentation on their cloud satellites which would be able to detect gamma and x-ray energies:
    Earth’s Gamma-Ray Bursts Triggered by Lightning
    “New observations from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) satellite raise the maximum recorded energy of TGFs [Terrestrial gamma-ray flashes] by a factor of ten and indicate that the Earth gives off about 50 TGFs every day, and possibly more.
    “The energies we see are as high as those of gamma rays emitted from black holes and neutron stars,” said David Smith, an assistant professor of physics at UC Santa Cruz and author of a scientific paper on this topic.
    The exact mechanism that accelerates the electron beams to produce TGFs is still uncertain, he said, but it probably involves the build-up of electric charge at the tops of thunderclouds due to lightning discharges. This results in a powerful electric field between the cloudtops and the ionosphere, the outer layer of Earth’s atmosphere.”
    If you really don’t want to know, that is the way not to find out. Just leave those energies out of your observations.

  19. Gosh, different disciplines comparing notes. What a novel idea. If they do this right, discoveries would be like being a kid in a candy store. There is no better moment than this one: “Ah Ha! So that’s how it works! Cool!” I think it would be so much fun to be at that convention of A Train scientists.

  20. Zeke the Sneak says:
    October 27, 2010 at 4:02 pm
    Guess they are watching their navels LOL!!! (are they dirty or not: To be or not To be…that´s the question!

  21. … one of the most powerful tools scientists have for understanding our planet’s changing climate.
    Trouble is our actual climate is not changing, yet, and colder’s the next direction. Smells of an arrow, not a train, aimed at any scientist with a skeptical mind.
    If these satellites show nothing unusual is happening, as is reality, I will be shocked!Might even start to have some trust in science again.

  22. At the great risk of being repetative:-
    More should be done to study the Sun & find out how it affects the Earth! As the IPCC freely admit, albeit unintentionally, they know very little about the Sun’s affect upon the planet, yet they are convinced CO2 over-powers it. They don’t know what effect element ‘A’ really has on element ‘B’, but they know for certain the element ‘C’ over-powers it! Flawless logic or what?

  23. Surely we need a railway person to lead this project.
    Does Mr. Pachauri have some time on his hands for this train now that Climate is going onto the backburner in favour of biodiversity?

  24. Based on the picture, above, it’s becoming quite littered with space junk up ‘there’ and we have to do something fast to counter the effect all these things are having on global temperatures. Perhaps it’s time to start letting the UN General Assembly vote on whether or not a country can put up another piece AGW space junk? I mean, if everyone in the world is as concerned as we’re told they are, then it only stands to reason that we need to do something like this, right? Heck, NASA says it serious, right? The ESA says it’s serious, right? And the BIGGEST piece of space junk, heating the most space, is the ISS, right? I’ll bet we could save an awful lot of money by NOT sending all that suff up there too. So, in order to get the best bang for the buck and be able to have enough CO2 to grow food for everyone plus a few trees, we need to immediately stop all launches and bring the folks back from the ISS via Atmospheric Friction Decelleration and Reentry Burnout and High Altitude Individual Bailout (AFC and RB and HAIB, for short). Oh Yes, Sarc off!

  25. Ref my last. Get a little dislexic sometimes, AFC should read AFD, don’t want NASA/ESA/Etc to get huffy or miffed.

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