Estimation of extreme sea levels over the eastern continental shelf of North America

Abstract

[1] This study presents distributions of extreme sea levels over the eastern continental shelf of North America (ECSNA) associated with storm surges and tidal surface elevations produced by a 2-D ocean circulation model for the period 1979-2010. The 2-D circulation model is driven by atmospheric and tidal forcing. The large-scale atmospheric forcing is the wind stress and sea level atmospheric pressures extracted from NCEP (National Centers for Environmental Prediction) Climate Forecast System Reanalysis (CFSR) fields at 6 h intervals. A parameterized vortex is inserted into the CFSR fields to better represent the atmospheric forcing associated with a tropical storm or hurricane. The tidal forcing includes specification of tides at model open boundaries and tide generating potential at each model grid. The model performance is assessed using observed sea levels over the ECSNA. The simulated surface elevations driven by the atmospheric force are used to estimate the 50 year return level of extreme sea levels associated with storm surges over the ECSNA using an extremal analysis. The potential regions of the ECSNA to be threatened by severe storm surges are presented. The extreme total sea levels due to tides and storm surges are also estimated using the Monte Carlo method from model results. Regions over the ECSNA experiencing severe 50 year extreme total sea levels due to the storm surges and tides are similar to those regions of 50 year extreme surge-induced elevations, but with much higher extreme values.Citation: Zhang, H., and J. Sheng (2013), Estimation of extreme sea levels over the eastern continental shelf of North America,

Numerical Modeling of Historical Storm Tides and Waves and Their Interactions Along the U.S. East and Gulf Coasts

“…Based on the balance between the accuracy and computational cost of the models used in our previous studies, we have selected a resolution between 1 and 100 km for the present study. The selected mesh resolution at the coast (∼1 km) and in the surf zone and shallow waters (i.e., water depth of 20 m or less) is an improvement compared to the resolution of computational meshes used in the previous basin‐scale studies (e.g., ∼ 5–7 km in Zhang and Sheng, ; ∼5 km in Muis et al, ). A finer mesh may improve the model accuracy but can increase the computational demand, which is not optimal for simulating a large number of historical storms in the present study and tens of thousands of synthetic storms in our subsequent basin‐scale flood hazard assessment study.…”

“…Recently, a few basin‐scale studies have been carried out to simulate a large number of historical storms and to present storm surge hazards over the entire basin. For example, Zhang and Sheng () presented the spatial distribution of water levels induced by tropical and extratropical cyclones over the eastern continental shelf of North America. They used the two‐dimensional (2‐D) depth‐averaged version of Princeton Ocean Model (POM), with a horizontal resolution of about 5–7 km, to simulate astronomical tides and storm surges during a 31 year period between 1979 and 2010.…”

“…In other words, due to the high computational cost of spectral wave models, these studies neglect storm waves and, in turn, the influence of waves on the water level. For instance, while the basin‐scale model of Zhang and Sheng () accounts for the influence of tide‐surge interaction on the water level, it neglects wave effects. In addition to waves, the global‐scale study of Muis et al () further neglects the influence of tide‐surge interaction on the water level.…”

A Bayesian Quantile Regression Approach for Nonstationary Frequency Analysis of Annual Maximum Sea Level in a Changing Climate

“…Several extreme value analysis techniques were developed to estimate the return periods of extreme sea levels (Bernardara;Andreewsky and Benoit, 2011;Kim, 2010, 2012;Woodworth and Blackman, 2002). Many studies have suggested the use of the GEV approach to estimate the extreme sea levels (Kim et al, 2016;Zhang and Sheng, 2013). Before applying NSFA, the data should be tested against trends or changes/shifts in the mean and variability in order to assess its stationarity or the nonstationarity (Hawkes et al, 2008).…”

Estimating Sea-Level Allowances for Atlantic Canada using the Fifth Assessment Report of the IPCC

“…The Gumbel model parameters and 50-year return levels for all tide-gauge stations show large spatial variations for Atlantic Canada (Table 3). The location parameter is equal to the (Bernier & Thompson, 2006;Zhang & Sheng, 2013). A smaller-scale parameter indicates that the return period is sensitive to small changes in mean SLR.…”