Dissecting the Sea Level Rise Signal in the Hampton Roads and Chesapeake Bay Area

The Sewell's Point tide gauge, located on the Hampton Rds. military base in Norfolk, VA, has shown trends in sea level greater than the global average. Local land subsidence in the region, caused by several geological factors, is believed to contribute greatly to this linear increase in sea level. Accounting for the seasonal variability in sea level can help increase our predicative capabilities of future rise. Here, the model for local sea level (LSL) is determined by fitting monthly averaged wind stress, atmospheric pressure, and ocean circulation time series to the monthly sea level time series at Sewell's Point obtained from the NOAA records. An annual and semi-annual cycle is added to the fit, accounting for most of the seasonal variability not explained by the forcing factors.

Two atmospheric forcing data sets, the NCEP and ERA40 reanalysis, were used for this research. Results from the regression analysis emphasize the zonal wind's role in the seasonal sea level cycle. The atmospheric pressure, north to south winds, and ocean circulation explain less variance in the LSL at Sewell's Point on the monthly timescale. Contributions from the forcing factors to sea level variability fluctuate depending on which forcing dataset was used.