Charting Magnetic Dip Poles and Associated Field Patterns

The elongated configuration of potential in the Arctic calls for special techniques of magnetic cartography. The paper explains the procedures developed by the author, involving the resolution of the horizontal components of the field vector and of the secular-change vector into components parallel and perpendicular to an appropriately chosen meridian. Stress is placed on the ways in which the presence of elongation affects certain postulates otherwise valid in the polar vicinity, and on the importance of appropriate treatment of secular change. The paper concludes with a discussion of the technique of deriving the drift of a dip pole.