T146 Recent Sea-Level Rise: Accelerating or Not?

Tuesday, 6 November 2012
8:00 AM - 12:00 PM
218AB

RELATIVE ROLE OF REGIONAL DYNAMIC FORCINGS ON SOUTHEASTERN US TIDE GAUGE PROJECTIONS OF RELATIVE SEA LEVEL RISE; THE PROGRESSION BETWEEN “WEATHER” AGGREGATING INTO “CLIMATE”

Paper number: T146-10
Program: Technical Sessions
Time: 10:25 AM – 10:40 AM

Authors

Abstract

In meeting with coastal communities to provide guidance on the projection and potential impacts of future sea level rise for the State of South Carolina it became evident that diverse simplistic projections of past regional sea level behavior from local tide gauges complicated discussion of future change and possible adaptation strategies with public and private interests. The gravest mode of local tide gauge records (trend) using empirical modem decomposition (EMD) showed that measured rate of sea level change in South Carolina has been decelerating through the entire period of observation at the sites of the two longest tide gauge time series. This result is similar to recently published reanalysis of historic tide gauge data and has presented a particular impediment to public discussion of adaptation to potential future climate change.

The magnitude of relatively short period drivers, seasonal to decadal can be quite large relative to the local “trend” and has also clouded discussions with policy makers seeking to address concerns for future sea level rise. A simple test of one short term dynamic influence on coastal water level, wind driven forcing of coastal waters towards or away from the coast, showed a high correlation with the measured water level data on seasonal to decadal scales. A similar analysis of adjacent regions where long-term rates of sealevel rise are accelerating faster than simple regression projections of tide gauge data also show a strong correlation on seasonal to decadal scales. Presentation of seasonal to decadal shifts in local “weather” patterns (wind direction and speed, precipitation etc.) as one component of longer-term “climate” driven change in sea level experienced along the Southeast US has found some success in discussion with local decision makers about the potential utility and need for adaptation planning for future projected rise in sea level so different than recent (decadal) experience and measurement.