The Project MAGNET mission provided a wealth of airborne-magnetometer data spanning the globe (Coleman, 1992). This dataset represents a single track of horizontal field intensities (a very small subset of the full collection!).
A dataframe with 2048 observations on the following 4 variables.
km
Relative along-track distance, in kilometers. The first observation is at zero kilometers.
raw
Raw intensities, in nanotesla.
clean
Edited raw intensities, in nanotesla
mdiff
The difference between clean
and raw
intensities, in nanotesla.
There are non-real data points in raw MAGNET series; these are instrumental artefacts, and can severely affect power spectral density (PSD) estimates. A clean series has been included so that a comparison of PSDs may be made.
Some command like subset(magnet, abs(mdiff) > 0)
can be used to identify the rows where edits have been made.
Coleman, R. J. (1992), Project Magnet high-level vector survey data reduction. In Types and Characteristics of Data for Geomagnetic Field Modeling, 3153, pp. 215-248.
pspectrum
, Tohoku
, hfsnm