Abstract
High-quality magnetic data are important in guiding new knowledge of the
solid earth in frontier regions, such as Antarctica, where these data
are often among the first data collected. The difficulties of data
collection in remote regions often lead to less than ideal data
collection, leading to data that are sparse and four-dimensional in
nature. Standard aeromagnetic data collection procedures are optimised
for the (nearly) 2D data that are collected in industry-standard
surveys. In this work we define and apply a robust magnetic data
correction approach that is optimised to these four dimensional data.
Data are corrected in three phases, first with operations on point data,
correcting for spatio-temporal geomagnetic conditions, then operations
on line data, adjusting for elevation differences along and between
lines and finally a line-based levelling approach to bring lines into
agreement while preserving data integrity. For a large-scale East
Antarctic survey, comparison with more traditional processing approaches
demonstrates superiority, gains in this case are relatively marginal for
phase 1 (3-5%) but more substantial for phase 2 (10-35%). For the full
implementation, median cross-tie error reduction is 89%, reaching a
final error of 8-9 nT. Residual errors are attributed to limitations in
the models used for in predicting the 4D geomagnetic conditions and also
some limitations of the inversion process used in phase 2. Nevertheless,
data have improved utility for tectonic and glacio-tectonic
interpretation and modelling, in particular quantitative approaches,
which are enabled with less bias and more confidence compared to
conventional processing.