Earth Sciences 1023A/B Lecture Notes - Lecture 17: Geomagnetic Reversal, Radiometric Dating, Continental Drift
25 Mar 2016
School
Department
Course
Professor
Document Summary
Since the 1960s, the earth"s magnetic field has been observed intermittently by satellites (300- The international association of geomagnetism and aeronomy maintains a standard global field model called the international. 11th- generation model, igrf11, was developed using data from satellites ( rsted, champ and sac-c) and a world network of geomagnetic observatories. Geomagnetic field changes constantly on time scales from milliseconds to millions of years. Short time scale variation in earth"s magnetic field: geomagnetic storms : interactions with the solar wind and. Earth"s magnetosphere: ionospheric fields: 80 200 km altitude above earth charged ions move around by differential heating and lunar tides. Since they are moving charges they create their own magnetic fields that interacts with earth"s. Large changes, which occur time scales of a year or more reflect changes in earth"s interior. Changes in declination (the angle between magnetic north and true north)
