Combination of geodetic observations and models for glacial isostatic adjustment fields in Fennoscandia
Artikel i vetenskaplig tidskrift, 2010
We demonstrate a new technique for using geodetic data to update a priori predictions
for Glacial Isostatic Adjustment (GIA) in the Fennoscandia region. Global Positioning
System (GPS), tide gauge, and Gravity Recovery and Climate Experiment (GRACE)
gravity rates are assimilated into our model. The technique allows us to investigate the
individual contributions from these data sets to the output GIA model in a self‐consistent
manner. Another benefit of the technique is that we are able to estimate uncertainties
for the output model. These are reduced with each data set assimilated. Any uncertainties
in the GPS reference frame are absorbed by reference frame adjustments that are estimated
as part of the assimilation. Our updated model shows a spatial pattern and magnitude
of peak uplift that is consistent with previous models, but our location of peak uplift
is slightly to the east of many of these. We also simultaneously estimate a spatially
averaged rate of local sea level rise. This regional rate (∼1.5 mm/yr) is consistent for
all solutions, regardless of which data sets are assimilated or the magnitude of a priori GPS
reference frame constraints. However, this is only the case if a uniform regional gravity
rate, probably representing errors in, or unmodeled contributions to, the low‐degree
harmonic terms from GRACE, is also estimated for the assimilated GRACE data. Our
estimated sea level rate is consistent with estimates obtained using a more traditional
approach of direct “correction” using collocated GPS and tide gauge sites.
GRACE
Glacial Isostatic Adjustment
GPS