Campbell Scientific WINDSONIC 2-D Sonic Wind Sensors - Manual (Page 37)

Appendix A. WindSonic Orientation
A.1 Determining True North and Sensor Orientation
The orientation of the WindSonic “North Arrow Markers” is found by reading
a magnetic compass and applying the site-specific correction for magnetic
declination; where the magnetic declination is the number of degrees between
True North and Magnetic North. Magnetic declination for a specific site can
be obtained from a USGS map, local airport, or through a NOAA web
calculator (Section A.2). A general map showing magnetic declination for the
Conterminous United States in 2004 is shown in FIGURE A-1.
FIGURE A-1. Magnetic declination for the conterminous United States
(2004)
A-1