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Re: [MSG-1] Haw valid are the precipitation images?

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  • Scott Sinclair
    ... Both weather radar and satellite based precipitation estimates are based on indirect methods i.e. compared to a rain gauge, which is basically a bucket to
    Message 1 of 3 , Sep 30, 2008
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      > "Ulrich G. Kliegis" <Ulrich.Kliegis@...> 09/30/08 10:22 AM
      > comparing the MPE precipitation images with other, radar based
      > observations

      > I see essential differences. How are these two image modalities linked and
      > validated?

      Both weather radar and satellite based precipitation estimates are based on indirect methods i.e. compared to a rain gauge, which is basically a bucket to catch a physical volume of water at a point.

      Since the radar and satellite are measuring different things (electromagnetic radiation at different wavelengths from very different positions - radar on the ground, satellite geostationary or earth orbiting) and using different techniques to estimate the precipitation, you can expect to see different results (and should be surprised if you don't!).

      Validation is a complicated (and largely unsolved) question and usually done by comparing the statistical properties of the different estimates (at a range of spatial and time scales), rather than by direct comparison.

      I hope that helps to shed a little light.

      Regards,
      Scott
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    • Ulrich G. Kliegis
      Scott, thanks for yor reply. It confirms my observation that the data from the two origins are (still) very different. At least, the rain radar images
      Message 2 of 3 , Oct 1, 2008
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        Scott,
        thanks for yor reply. It confirms my observation that the data from the two
        origins are (still) very different. At least, the rain radar images distributed by
        the DWD are pretty congruent with the local needs for umbrellas, oilies or
        massive roofs. Thus, they could serve the satellite signal processors as a
        reference to come close to.

        Cheers,
        U.


        On 1 Oct 2008 at 8:51, Scott Sinclair wrote:

        > I hope that helps to shed a little light.
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