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Satellites Show That Earth Has a Fever

Posted by simoniker on from the worldwide-baywatch dept.

Roland Piquepaille writes "A recent study from NASA says that satellites are acting as thermometers in space. Contrary to meteorological ground stations which measure the air temperature around two meters above the ground, satellites can accurately measure the temperature of the Earth's skin. And this new study, which covers the 18-year period going from 1981 to 1998, shows that the Earth's temperature is rising 0.43C per decade instead of the O.34C found by previous methods. Unfortunately for us, if satellites can more precisely measure this rise of the Earth's temperature, they cannot cure this fever. This overview contains more details and a spectacular image showing the European heat wave of the summer of 2003."

2 of 596 comments (clear)

  1. Well, actually, by Space+cowboy · · Score: 5, Informative

    Quite apart from the fact that sometimes life didn't go on (which ought to be enough to concern anyone), if you look at how these phenomena manifest, you'll see that it's typically not a linear process. There's normally a critical point over which X happens and below which Y happens. If X is lethal to human life (snowball earth, greenhouse earth) then we'd damn well better hope we stick with Y.

    A case in point is the atlantic conveyer (the 'Gulf Stream' to us Brits). If the conveyer stops, an absolutely massive amount of energy will cease to be delivered to where it currently is. The knock-on effects aren't really model-able, we just don't have the knowledge, but since staggeringly enormous amounts of warmth would cease to be delivered to the UK coastline, you could assume it will get colder, even if you don't know quite how much. To give some perspective, it generates a difference of approximately 20 degrees celcius between points at the same latitude. 20 degrees of delta-T over several hundred billion tons of water is a lot of energy to be dependent on far-easier-to-change salinity level.

    The atlantic conveyer depends on salinity in different parts of the world. If it rains more (in places that it currently rains little) and rains less (in places where it currently rains significantly) the saline levels will change, and the conveyer will be affected - at the critical point, it will simply stop. There's no obvious way we could restart it either. Shifting several hundred billion tons of water is way beyond our capabilities, and restoring the initial conditions may not be sufficient.

    I guess I'm sufficiently worried about the consequences (which we will not be able to counter) to pay some heed to people who try to assess risk under next-to-impossible scientific conditions. I guess, given the potential consequences, that I'm willing to listen more to those who get off their backsides and put some effort into the analysis than people who sit around saying, 'hell we've had ice ages before and we will again'.

    Actually humankind hasn't had ice-ages before, and to suggest we'd just cope is hubris of the highest order. We live in a highly technological society, and yes, given an immense struggle I think we would probably cope, as in 'Western civilisation' would cope. Countless millions would die in poorer, less developed, and simply unluckily-positioned countries as weather systems went out of control. One other thought is that a highly-structured, lean-and-mean (due to commercial pressures, mainly) society is a vulnerable society. If central America were reduced to a desert (unlikely, but possible) then the food chain would break within the US, and other countries would have a hard-enough time to feed their own. 280 million people is a lot of mouths...

    Simon

    --
    Physicists get Hadrons!
  2. The technology behind these satellites... by Van+Halen · · Score: 5, Informative
    I happen to work for a company that manufactures and sells some of these satellite-based temperature sensors to the government. I actually work on the ground processing software for one of them, which has all kinds of neat algorithms for turning raw microwave spectrum measurements into meaningful science data, including surface temperature and air temperature at several different levels of the atmosphere. If anyone is interested in the technology behind them, here are just a few of the sensors used by the US government for these purposes:

    MSU - 1970s era air temperature

    AMSU - next generation of MSU, several are flying on US and European satellites ATMS - next generation AMSU, scheduled for first flight in a few years SSM/T-1 - old 1970s/80s era air temperature sensor, the last one launched in 1999 SSMIS - next generation SSM/T-1 that also combines functions of 2 other older sensors (atmospheric water vapor and a ton of surface data like ice concentration, sea surface wind speed, soil moisture, etc), the first of 5 launched in October of last year CMIS - next generation SSMIS scheduled to fly by the end of the decade

    All of the above are what are known as microwave sounders or radiometers. They look at radiation in specific bands in the microwave region of the spectrum (based on oxygen absorption lines) to infer air temperatures.

    It looks like the study in the article was using MODIS and TOVS data. TOVS consists of some of the above instruments - MSU and AMSU in particular for this application. MODIS is another sensor that doesn't look at the microwave region of the spectrum, so it's out of my area of expertise. Look at the website for more info on that if you're interested. :)

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