Towards a New Baseline of Vertical Land Motions in the Chesapeake Bay
Using GNSS and InSAR
Abstract
Relative sea-level rise is a major coastal hazard affecting about half
the population of the United States. The Chesapeake Bay is characterized
by the fastest rate of sea-level rise along the Atlantic coast of North
America, in part because of land subsidence. Previous studies have
quantified a range of land subsidence rates in the Chesapeake Bay
(~1-4 mm/yr) from various measurement techniques that
contribute to high rates of relative sea-level rise. In this study, we
present progress towards developing a new vertical land motion map for
the Chesapeake Bay region to provide more robust constraints on
estimates of relative sea-level rise. We are using a combination of GNSS
observations and InSAR interferograms. Available continuous GNSS data in
the region that span November 2014 - September 2020 are processed with
GAMIT-GLOBK to align temporally with available Sentinel-1 InSAR
satellite data. We are using an approach that combines the two geodetic
observations to provide a new solution of vertical land motions for the
Chesapeake Bay. Additionally, this project is collecting new campaign
GNSS observations across the Chesapeake Bay each fall for 5 years,
beginning in 2019. We will also present about the 2020 and planned 2021
campaign GNSS observations, which will ultimately be incorporated into
our new map of vertical land motions for the region. The impacts of this
work will be improved flooding and inundation hazard maps, as well as
updated projections for municipal flood mitigation planning that will be
created using the new dataset.