Secular variation refers to the long-term changes or trends observed in a particular phenomenon over an extended period, typically spanning decades to centuries. This term is commonly used in various fields, such as geology, paleoclimatology, and even economics, to describe gradual changes that are not tied to periodic cycles (like seasonal or annual changes). In the context of geology and geomagnetism, secular variation may refer to the gradual changes in the Earth's magnetic field intensity and direction over time.
New to topics? Read the docs here!