Examining the role of land motion in estimating altimeter system drifts
Event: 2015 Ocean Surface Topography Science Team Meeting
Session: Science I: Mean sea level monitoring: how to reconcile altimetry, tide gauges, land motion and other in situ observations?
Presentation type: Type Oral
Contribution: PDF file
In the ongoing attempt to determine mission-specific satellite altimeter bias drift via comparison with the tide gauge network, accurate estimates of vertical land motion (VLM) at tide gauges are essential. Previous drift studies have used a variety of VLM estimates or methodologies [e.g. Watson et al., 2015; King et al., 2012; Mitchum 2008], but none have evaluated the full range of VLM estimates. We consider VLM estimates from a variety of methods, including King et al. (2012, updated), JPL’s GPS time series (http://sideshow.jpl.nasa.gov/post/series.html), the Université de La Rochelle ULR5 (Santamaria-Gomez 2012), and Doran (2010), and produce individual drift bias estimates for each mission with each VLM solution.
We find that the drift estimates from both the combined TOPEX/Jason-1/Jason-2 dataset and the combined Envisat/AltiKa record vary by ~0.5 mm/year depending on the VLM estimate. We will discuss the implications of VLM choice and station selection criteria on the drift estimates.