National Assessment of Coastal Vulnerability to Sea-Level Rise: Preliminary Results for the U.S. Atlantic Coast
Figure 4. Map of the Coastal Vulnerability Index for the New York to New Jersey region.
Figure 8. Map of the Coastal Vulnerability Index for the North Carolina to Georgia region.
The data underlying the coastal vulnerability index (CVI) show variability at several spatial
scales. The rate of sea-level rise, and tide range vary over a
spatial scale of >100 km. In the case of sea-level rise, this
represents the large-scale patterns of isostasy and tectonism
present along the Atlantic continental margin of North America
(Peltier, 1996; Braatz and Aubrey, 1987). Changes in tide range
generally reflect changes in the configuration of the continental
shelf as a whole (e.g., shelf width).
A second group of variables, consisting of geomorphology and
wave height, vary on a ~10 km scale that reflects primarily the
landward changes in environments and energy in the coastal system.
For example, there is a nearly continuous chain of barrier islands
backed by estuaries and lagoons along the open-ocean coast from
eastern Long Island, New York to the Florida Keys.
The shoreline erosion/accretion rates vary on a spatial scale
equal to the minimum size of our grid, which is 3 minutes or ~6 km.
It is this variable which adds the greatest variation to the CVI
values. As described above, this is also the variable in our data
set that is the least well-documented.
To highlight the nature of the CVI and its underlying data,
different index variables from two geographic regions are presented
on the next two pages: