Earth Sciences 1023A/B Lecture Notes - Lecture 18: Motonori Matuyama, Gravitational Constant, Solar Wind

• School: Western University
• Department: Earth Sciences
• Course: Earth Sciences 1023A/B
• Professor: Richard Secco

Document Summary

Lecture 18: earth"s magnetic field changes over time of years. patterns of motion in the core, is referred to as secular variation. by differential heating and lunar tides. Since the 1960s, the earth"s magnetic field has been observed intermittently by satellites (300-900 km altitude). Geomagnetic field changes constantly on time scales from milliseconds to millions. Short time scale variation in earth"s magnetic field: (cid:883). Geomagnetic storms: )nteractions with the solar wind and earth"s magnetosphere: ionospheric fields: 80 200 km altitude above earth charged ions move around their own magnetic fields that interacts with earth"s. Long time scale variation in earth"s magnetic field: the slow (cid:523)non-periodic) variation in the geomagnetic field, due to the changing, typical variations are on the order of years to (cid:883)(cid:882)(cid:882)(cid:882)"s of years. Large changes, which occur time scales of a year or more reflect changes in earth"s.