Recent improvement in the KMS global marine gravity field

During the first half of 1998, the procedure for deriving the KMS global
marine gravity field (Andersen and Knudsen, 1995, 1996) was revised. The
resolution was enhanced, and several parameters were tuned to obtain a better
gravity field. The updated procedure for the new KMS98 gravity field and their
differences with the procedure for deriving the older KMS96 gravity field is
presented in this paper. An important tool in the improvement of the KMS gravity
field was the use of high quality marine gravity observations to check possible
finetuning of parameters. Testing and comparison with other recent global marine
gravity fields is carried out in regions of rapid changing gravity signal like over
trenches and sea mounts to illustrate the improvement in the new gravity field. The
improvements involved a better spatial varying filter for the interpolation of the
geoid anomalies depending on the local RMS variability, and an enhanced filtering
in the conversion between geoid anomalies and gravity. The KMS98 gravity field is
available at the Internet-address: ftp://ftp.kms.dk/pub/GRAVITY, which also,
contains information on how to use the field.