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Some good anaprop today

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  • 11-10-2010 7:26am
    #1
    Su Campu
    Closed Accounts Posts: 4,279 ✭✭✭


    Looking at this morning's radar you'd be forgiven for thinking it was raining in the northwest. But there's no rain; those echos are actually reflections from the Scottish terrain, and the process is called Anomalous Propogation (anaprop).

    It happens during strong anticyclones, in which there is a subsidence inversion in the lower troposphere (an abrupt layer of much warmer and drier air a few thousand feet up, caused by the subsiding air from upper levels, which warms and dries as it does so....see the Castor Bay 00Z sounding). The radar beam reflects of the inversion and travels much further than normal. It will reflect off distant terrain (Scotland, for example) and the echo will return back the the receiver the same way, showing a return. In this case, the Shannon radar is picking up the anaprop in the northwest, and the Dublin one is showing it south of the Mourne Mtns and over Wales.

    attachment.php?attachmentid=130541&stc=1&d=1286778229

    2010101100.03918.stuve700.gif

    This process should get stronger over the next day or two as the High moves down over us, so don't be giving Shannon radar a hard time - for once it's not it's fault!!!


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    #2
    kc56
    Registered Users Posts: 431 ✭✭kc56


    The coverage over Donegal is from the Dublin radar. This was shown quite well a few weeks ago http://www.boards.ie/vbulletin/showthread.php?t=2055967796&page=6

    So the echoes over Donegal are reflections from high ground in Donegal and not Scotland.


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    #3
    BEASTERLY
    Registered Users Posts: 1,789 ✭✭✭BEASTERLY


    kc56 wrote: »
    The coverage over Donegal is from the Dublin radar. This was shown quite well a few weeks ago http://www.boards.ie/vbulletin/showthread.php?t=2055967796&page=6

    So the echoes over Donegal are reflections from high ground in Donegal and not Scotland.

    In Su campu's defence I think this is different from the regular echoes off high ground.


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    #4
    Su Campu
    Closed Accounts Posts: 4,279 ✭✭✭Su Campu


    Yes, the other thread had nothing to do with anaprop. It was to do with interior errors in the Shannon system itself.

    The current radar's now showing intense echos in the northern half of the country, pity we can't get a real setup like that and we'd be in business!!! :D

    130657.png

    Look at the strength of the inversion in the 12Z Castor Bay!!! :eek:

    2010101112.03918.skewt.gif


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    #5
    kc56
    Registered Users Posts: 431 ✭✭kc56


    Su Campu wrote: »
    Yes, the other thread had nothing to do with anaprop. It was to do with interior errors in the Shannon system itself.
    No, but it does illustrate which parts of the image get data from Shannon and Dublin. Donegal is covered by Dublin and therefore the echoes over Donegal are not Shannon seeing Scotish mountains but simply ANAPROP on the Dublin radar.

    This is probably one of the most severe cases of ANAPROP seen. While anaprop from Wales, IOM etc is quite common, it is much rarer from inland areas.


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    #6
    kc56
    Registered Users Posts: 431 ✭✭kc56


    BEASTERLY wrote: »
    In Su campu's defence I think this is different from the regular echoes off high ground.
    Absolutely correct. Su campu's explanation of the echoes is correct apart from the Scotland bit.


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    #7
    dexter647
    Registered Users Posts: 1,217 ✭✭✭dexter647


    Learn something new everyday. Was wondering what was up with the radar readings... Cheers:)


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    #8
    Su Campu
    Closed Accounts Posts: 4,279 ✭✭✭Su Campu


    kc56 wrote: »
    No, but it does illustrate which parts of the image get data from Shannon and Dublin. Donegal is covered by Dublin and therefore the echoes over Donegal are not Shannon seeing Scotish mountains but simply ANAPROP on the Dublin radar.

    This is probably one of the most severe cases of ANAPROP seen. While anaprop from Wales, IOM etc is quite common, it is much rarer from inland areas.

    Yes, you're right, it is being picked up from Dublin. ;-)


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