A Hybrid Dynamical Approach for Seasonal Prediction of Sea‐Level Anomalies: A Pilot Study for Charleston, South Carolina

Abstract

With global-mean sea level (SL) rising at an accelerating pace (Frederikse et al., 2020;Nerem et al., 2018), many coastal cities around the globe face an increase in extreme SL and coastal flooding events (Moftakhari et al., 2015;Thompson et al., 2021;Wahl et al., 2014). For example, over the last several years, many coastal cities around the United States have started experiencing high-tide flooding (HTF) events. HTF events are floods not primarily caused by large storm systems, but due to high tides and regular variations in atmospheric and oceanic conditions (Sweet et al., 2020). Accurate predictions of such flooding events, or even assessments of coastal flooding probabilities could possibly be a valuable tool for coastal communities to prepare for these events. However, it is challenging to accurately predict such events up to a few months ahead in part because we

Acceleration of U.S. Southeast and Gulf coast sea-level rise amplified by internal climate variability

“…These results support the idea of an advective transfer of density signals from the Caribbean Sea via the larger Gulf Stream system into the Gulf of Mexico and the coastal zones south of Cape Hatteras. This is further supported by recent sensitivity experiments in the adjoint model of the Estimating Circulation and Climate of the Ocean system 56 that pointed to a strong physical linkage between MSL in Charleston, South Carolina, and wind stress forcing (as well as heat and freshwater fluxes) over the Caribbean Sea (maximizing when the latter leads by four to eight months). In line with that, ref.…”

“…4b, c). We demonstrate that most of the internal variability in coastal MSL is coherent with open ocean wind stress forcing through westward propagating Rossby waves in the tropical North Atlantic that may affect variability in the inflow of water masses into the Caribbean Sea, the Gulf of Mexico, and ultimately the Subtropical Gyre as a whole [55][56][57] . Showing peak-to-peak variations of ~45 mm (~25 mm due to open ocean wind stress forcing with additional contributions from coastal longshore winds and river discharge) on muti-year timescales such internal variability may either mask or amplify externally forced trends and acceleration along this coastline.…”

What Forcing Mechanisms Affect the Interannual Sea Level Co‐Variability Between the Northeast and Southeast Coasts of the United States?

“…The wave‐like patterns shown in maps of sea level sensitivity to wind stress as a function of forcing lead time are consistent with this mechanism (Figure S1 in Supporting Information ; also see Figure 4 of Frederikse et al. (2022)). We have analyzed the propagating wave patterns shown in these sensitivity maps.…”

“…Rossby waves induced by wind stress curl likely cause the westward prorogation of this offshore contribution (Calafat et al, 2018;Dangendorf et al, 2023;Domingues et al, 2016). The wave-like patterns shown in maps of sea level sensitivity to wind stress as a function of forcing lead time are consistent with this mechanism (Figure S1 in Supporting Information S1; also see Figure 4 of Frederikse et al (2022)). We have analyzed the propagating wave patterns shown in these sensitivity maps.…”

Nonstationary Roles of Regional Forcings in Driving Low‐Frequency Sea Level Variability Along the U.S. East Coast Since the 1950s

“…Previous studies have demonstrated the importance of regional forcings, including alongshore wind stress over the shelf, local sea level pressure (SLP) through the Inverted Barometer (IB) effect, and river discharges in causing interannual to decadal SLAs along the USEC, especially north of Cape Hatteras (e.g., Blaha, 1984; Li et al., 2014; Piecuch, Dangendorf, et al., 2016; Piecuch, Thompson, & Donohue, 2016; Piecuch et al., 2018; Piecuch & Ponte, 2015; Woodworth et al., 2014). Remote forcing from the open ocean to the east, and coastal wave propagation and advection from the subpolar region to the north can also influence USEC sea level (e.g., Bingham & Hughes, 2009; Diabaté et al., 2021; Ezer, 2013; Ezer, 2019; Ezer et al., 2013; Frederikse et al., 2017; Frederikse et al., 2022; Hong et al., 2000; Little et al., 2017; Minobe et al., 2017; Thompson & Mitchum, 2014; Wang et al., 2022; Yin & Goddard, 2013). We focus on regional forcings starting from the 1950s when much more tide gauge measurements and more accurate regional SLP and wind stress data are available (e.g., Bell et al., 2021).…”