Altimetry enhanced free-air gravity anomalies in the high latitude region

Abstract

Available marine free-air gravity anomalies (FAGA) derived from multiple satellite altimetry missions have had geologically useful, short wavelength features removed during processing. An approach is described for augmenting these FAGA in the high latitude region with coherent higher frequency data. This added-value approach is demonstrated over the Barents Sea in the Arctic using existing FAGA predictions from the Danish National Cadastre (KMS98) as a reference. Short wavelength components between 4 and 111 km were added from reduced and correlation-filtered ERS1 168-day mission altimetry that had been sorted into ascending and descending datasets for separate processing. The processed data were then recombined by spectral quadrant swapping to generate a correlated, high frequency gravity field related to the local geologic sources. This added-value surface adjusted the reference FAGA to better reflect features at wavelengths related to the distances between altimetry tracks.