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NASA Confirms Rainy Cities

Posted by timothy on from the view-from-above dept.

Devil's BSD writes: "It's true, urban areas are rainier than rural areas. Using the Tropical Rainfall Measuring Mission satelite to measure rainfall around cities, NASA found that areas downwind from cities had up to 116% more precipitation than those upwind from it. The cause? The major heat difference, up to about 10 degrees Fahrenheit (5.6 Celsius degrees), caused by the asphalt and concrete in cities. This story is posted on the Goddard Space Flight Center page."

3 of 21 comments (clear)

  1. It's particulate matter that matters by CTalkobt · · Score: 2, Insightful

    ( Pardon the pun ).

    This has been known for some time. The claim, when I heard it, was that particulate matter in the air from exhaust etc gave the water vapor something to coallese onto and hence form water droplets. I think particulate matter is more reasonable to expect than temputure variations ( even tho these do exist ).

    Why is Nasa re-inventing what is already known? This was out about 5 years ago ( or longer - memory rentention tends to blur ).

    --
    There's a gorilla from Manilla whose a fella that stinks of vanilla and has salmonella.
  2. causation by Anonymous Coward · · Score: 1, Insightful

    The cause? The major heat difference, up to about 10 degrees Fahrenheit (5.6 Celsius degrees),

    post hoc ergo proctor hoc

    I'm too lazy to read the science and peer review it, but lots of cities sprung up around rivers (for trade & transportation), so the area might have been rainier before the city appeared to support the river.

    Without before/after rain measurements, I can't accept their conclusions.

    1. Re:causation by Matthias+Wiesmann · · Score: 4, Insightful
      Indeed many cities are built on the border of rivers, but those rivers exist before they flow into the city and after they run out of it.

      So if the change of temperature was only caused by the body of water, the whole river would cause rain down-wind (this is probably true, but is an orthogonal problem).

      Claiming that the observed effects can be explained by the rivers would imply that those river do not exist outside of the city...