Navigation

    Windy Community

    • Register
    • Login
    • Search
    • Unread
    • Categories
    • Groups
    • Go to windy.com

    Indicate model terrain height and faq on atmospheric levels

    Your Feedback and Suggestions
    2
    2
    489
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • D
      drmatt | Premium last edited by

      Hi. I've looked through the FAQ but cannot seem to find a clear answer to how atmospheric levels relate to model terrain height. For instance, in a large mountain range, the averaged elevation of the 9 km grid cell of the DEM may be 4000 ft. If I want to know the predict wind speed at the surface here, do I look at the Surface value or the 4000 ft value? Similarly, if the cloud bases are predicted to be 4000 feet here, does this mean 4000 feet above the 4000 foot elevation, or does this mean the clouds are at the surface? If it does, how do I physically interpret data from atmospheric levels that are below model terrain level, since they clearly show dynamics here. And if the atmospheric levels are relative to model terrain surfaces, how do I interpret or visualize how winds at 14,000 foot atmospheric level intersect a 18,000 foot mountain?

      I'm sure this question has been asked before, so please point me towards the answer if it is here somewhere. And again the question is not about the impact of the difference between model terrain and actual terrain, but rather how to interpret the atmospheric height levels relative to model terrain.

      I think in any case, as something for your large the suggestion box, I think it it would be handy for the user to know the DEM's elevation, perhaps with a tool tip, or a check box that makes it appear on meteograms, or simply a colored overlay on the map window. The app is so awesome this feature is probably here already and I'm missing is, so I apologize if so!

      Thanks!

      Gkikas LGPZ 1 Reply Last reply Reply Quote 1
      • Gkikas LGPZ
        Gkikas LGPZ Moderator @drmatt last edited by Gkikas LGPZ

        @drmatt

        Some related posts:
        https://community.windy.com/topic/4513/what-elevation-for-spot-forecasts

        https://community.windy.com/topic/5674/terrain-effects

        https://community.windy.com/topic/4219/terrain-height-v-s-forecast-height

        Vertical structure of the grid points in a model:
        upper levels are close to the pressure coordinate
        while lower levels are terrain-following.
        0_1529385120043_49a958b4-8c8b-49ff-8720-f26d1608d37c-εικόνα.png
        Source: http://www.hko.gov.hk/wservice/tsheet/nwp.htm

        For further reading:
        ICON model
        https://www.dwd.de/SharedDocs/downloads/DE/modelldokumentationen/nwv/icon/icon_dbbeschr_aktuell.html

        ECMWF model, forecast user guide:
        https://software.ecmwf.int/wiki/display/FUG/Forecast+User+Guide

        P.S. I agree with you that windy must appear model's orography on meteograms (in the "about location" section).
        e.g. for Bern, Switzerland
        0_1529386620978_491bfaac-cf31-46fb-8704-a6dd93e40b55-εικόνα.png

        1 Reply Last reply Reply Quote 1
        • First post
          Last post
        Windyty, S.E. - all rights reserved. Powered by excellent NodeBB
        NodeBB & contributors, OSM & contributors, HERE maps
        Terms and Conditions     Privacy Policy