Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Refraction at the horizon.
    From: Marcel Tschudin
    Date: 2008 Mar 19, 11:20 +0200

    ... when I wrote last night the above comment related to the powers of
    temperature and pressure I should have added that I don't understand
    (yet) the reason for it. I therefore can't absolutely exclude an
    artefact of the calculation itself. However, thanks to Andrew T. Young
    the program could be tested beforehand carefully on several less and
    more critical bench mark calculations. The more critical cases were
    situations just at the edge before ducting occurs and situations with
    ducting, this for different observer positions. The results compared
    well. We found that the (small) differences we had resulted mainly
    from calculating/using gravity slightly different when calculating the
    pressure for the different layers. Andy used one same gravity value
    for all layers, calculated for an intermediate hight of the atmosphere
    (which is for his simulations absolutely sufficient) whereas in my
    model the gravity is calculated for an intermediate height within each
    layer.
    
    When I dug again in the files which were produced one year ago I
    selected "a" set of available graphs without finding out whether they
    really corresponded to the latest results found at that time. The aim
    was to show you what I meant with exponential behaviour, not more.
    It's clear that it would be interesting to understand the reason for
    this.
    
    Marcel
    
    --~--~---------~--~----~------------~-------~--~----~
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To unsubscribe, email NavList-unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
    Email:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site