Campbell-scientific RAWS-H Remote Automated Weather Station Manuel d'utilisateur télécharger pdf (Page 25)

RAWS-H Remote Automated Weather Station

9.2 USGS Web Calculator

The USGS provides an easy way of determining the declination of a specific

site. Since magnetic declination fluctuates with time, it should be adjusted

each time the wind sensor orientation is adjusted. The calculator can be

accessed at: www.ngdc.noaa.gov/geomagmodels/Declination.jsp. FIGURE 9-4

shows an example for Logan, UT.

FIGURE 9-4. USGS web calculator

In the example above the declination for Logan, UT is 12º 24′ or 12.4º. As

shown in FIGURE 9-4, the declination for Utah is east (positive), so True

North for this site is 360 – 12.4 = 347.6 degrees. The annual change is 7

minutes west per year or ─7 minutes/year.

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Campbell-scientific RAWS-H Remote Automated Weather Station Manuel d'utilisateur Page 25