NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Vertical Angle Measurement Errors
From: Marcel Tschudin
Date: 2013 Apr 2, 12:46 +0300
-> sea surface temperature (SST possibly from http://ourocean.jpl.nasa.gov/ see G1SST) or/and sea temperature from a buoy. My Hs measurements show indeed a correlation with the temperature difference between SST and air.
-> Cloud cover. You possibly ask now why also cloud cover. For his studies in Archaeoastronomy Victor Reijs had the idea to relate terrestrial refraction to the atmospheric Stability Classes. You find more on this on his Web-page(s) http://www.iol.ie/~geniet/eng/stabilityclasses.htm The Stability Classes could possibly indeed contribute to an improved dip estimate.
-> Nearest meteorological station (having comparable conditions to observer location) providing archived data records (via e.g. http://english.wunderground.com)
-> Nearest radio sounding station (having comparable conditions to observer location) providing archived data records (via e.g. http://weather.uwyo.edu/upperair/sounding.html or via http://www.ncdc.noaa.gov/oa/climate/igra/index.php?name=coverage )
From: Marcel Tschudin
Date: 2013 Apr 2, 12:46 +0300
Bruce, regarding your dip measurements you wrote:
In case these measurements will be done in view of producing a larger data set allowing (hopefully) to arrive at an improved way to estimate the dip, then the "etc." may eventually also stand for e.g:
Wave height, temp, wind, time, tide etc will be observed/recorded. Knowing how variable waves can be, an effort will be made via the angle measurements to estimate wave height where sighting.
-> sea surface temperature (SST possibly from http://ourocean.jpl.nasa.gov/ see G1SST) or/and sea temperature from a buoy. My Hs measurements show indeed a correlation with the temperature difference between SST and air.
-> Cloud cover. You possibly ask now why also cloud cover. For his studies in Archaeoastronomy Victor Reijs had the idea to relate terrestrial refraction to the atmospheric Stability Classes. You find more on this on his Web-page(s) http://www.iol.ie/~geniet/eng/stabilityclasses.htm The Stability Classes could possibly indeed contribute to an improved dip estimate.
It may eventually also be useful to know:
-> Nearest meteorological station (having comparable conditions to observer location) providing archived data records (via e.g. http://english.wunderground.com)
-> Nearest radio sounding station (having comparable conditions to observer location) providing archived data records (via e.g. http://weather.uwyo.edu/upperair/sounding.html or via http://www.ncdc.noaa.gov/oa/climate/igra/index.php?name=coverage )
Marcel
