Climate‐Based Emulator of Distant Swell Trains and Local Seas Approaching a Pacific Atoll

Abstract

The general understanding of coastal inundation in the low-lying nations of the Pacific areas relates flooding to extreme water levels (i.e., astronomical tides, sea level variability) or tropical cyclones (Hoeke et al., 2013). Nevertheless, distant-source swells are less studied (Hoeke et al., 2013) and are one of the main causes of coastal flooding in the Pacific (Ford et al., 2018). After traveling thousands of kilometers (Snodgrass et al., 1966), swell dissipation results in wave set-up due to breaking waves and infragravity waves (Pomeroy et al., 2012), increasing the local impact when they reach the reef-lined coast. Furthermore, differently to tropical storms which may have more localized impacts, far-field swells can cause flooding damage among a large number of Pacific islands and atolls at the same time, as it happened in the inundation event of December 2008 (Hoeke et al., 2013).

Wave Climate Variability and Trends in Tuvalu Based on a 44‐Year High‐Resolution Wave Hindcast

“…A comparison between the method of Cagigal et al. (2021) and our simplified method showed little, negligible difference in the results.…”

“…To investigate how much wave energy a particular atoll experiences from the open ocean, we extracted the directional energy spectra from two to four points surrounding each of the atolls and merged the spectra into one single “superpoint” spectrum loosely following Cagigal et al. (2021). As a simplification from Cagigal et al.…”

“…As a simplification from Cagigal et al. (2021) who split the superpoint in different sectors pointing toward the area of interest, here we created the superpoint by using the maximum energy density of each spectral frequency‐direction bin across the various spectra (Figure 7). As the points we selected were close to the coast wave directions point toward the islands and only energy pointing toward the coastline was picked up by each point.…”

Coastal Wave Extremes around the Pacific and Their Remote Seasonal Connection to Climate Modes

“…For instance, Ranasinghe et al [45] and Anderson et al [46] observed shoreline rotation at embayed beaches, and Trombetta et al [47] observed an alongshore sediment drift reversal with large consequences for coastal zone management and infrastructures. These remote swells can also drive dramatic overtopping [6] even at storm-free areas, such as in the Gulf of Guinea [1,48], facing the South Atlantic storm track, and in the Pacific due to distant tropical cyclones [17,[49][50][51].…”

Understanding the Natural Variability of Still Water Levels in the San Francisco Bay Over the Past 500 yr: Implications for Future Coastal Flood Risk

“…Anderson et al (2019Anderson et al ( , 2021 developed the Time-varying Emulator of Short and Long-term Analysis (TESLA) for coastal flood hazard assessment and applied the approach in San Diego, CA, by linking emulated TWLs with synoptic scale climate patterns at interannual (El Niño Southern Oscillation, ENSO) through intra-seasonal (Madden Julian Oscillation, MJO) timescales. Importantly, few statistical emulators (Anderson et al, 2019;Cagigal et al, 2020Cagigal et al, , 2021 incorporate atmospheric forcing, which can be crucial for understanding the drivers of extreme coastal flood events as suggested by Barnard et al (2015) and Marcos et al (2015).…”