SCALAR MAGNETIC ANOMALY MAPS OF EARTH DERIVED FROM POGO AND MAGSAT DATA

A new POGO scalar magnetic anomaly map at 400 km altitude is presented which consists of spherical harmonics of degree 15-60. On the basis o f the common features of this map with two new Magsat anomaly maps, da wn and dusk, two scalar magnetic anomaly maps of the Earth are present ed using two selection criteria with different levels of stringency. T hese selection criteria suppress the nonclustal components of the orig inal maps by different amounts. The more stringent selection criteria seek to eliminate as much contamination as possible, at the expense of suppressing some anomaly signal. This map is represented by spherical harmonics of degree 15-60. The less stringent selection criteria seek to retain as much crustal signal as possible, at the expense of also retaining some contaminating fields. This map is represented by spheri cal harmonics of degree 15-65. The resulting two maps are highly corre lated with degree correlation coefficients greater than 0.8.