Tropical cyclone rainbands can trigger meteotsunamis

Abstract

Tropical cyclones are one of the most destructive natural hazards and much of the damage and casualties they cause are flood-related. Accurate characterization and prediction of total water levels during extreme storms is necessary to minimize coastal impacts. While meteotsunamis are known to influence water levels and to produce severe consequences, their impacts during tropical cyclones are underappreciated. This study demonstrates that meteotsunami waves commonly occur during tropical cyclones, and that they can contribute significantly to total water levels. We use an idealized coupled ocean-atmosphere-wave numerical model to analyze tropical cyclone-induced meteotsunami generation and propagation mechanisms. We show that the most extreme meteotsunami events are triggered by inherent features of the structure of tropical cyclones: inner and outer spiral rainbands. While outer distant spiral rainbands produce single-peak meteotsunami waves, inner spiral rainbands trigger longer lasting wave trains on the front side of the tropical cyclones.

Weather radar and ancillary observations of the convective system causing the northern Persian Gulf meteotsunami on 19 March 2017

“…These resonances are the most efficient when the speed of the atmospheric meteotsunamigenic forcing is equal to the speed of long ocean or edge waves over several wavelengths of atmospheric disturbance (Hibiya and Kajiura 1982;Vilibić 2008;Šepić et al 2015a), while they are potentially further amplified by coastal shallowing and other topographic changes (Vennell 2010; Williams et al 2020). The drivers of these meteotsunamigenic disturbances may be of different atmospheric origins: (1) wave-ducting, which has been largely researched in the Mediterranean, a known meteotsunami hot spot (Monserrat and Thorpe 1996); (2) squall lines (Churchill et al 1995;Paxton and Sobien 1998); (3) wave-CISK (convective instability of the second kind, Belušić et al 2007); (4) fast moving storms such as derechos Bechle et al 2016); (5) convective cells (Sibley et al 2016;Williams et al 2019); (6) tropical cyclones and hurricanes (Shi et al 2020) and others. However, all of these atmospheric processes are highly mesoscale and require non-standard meteorological measurements at a high resolution, which are rarely available from regular meteorological networks.…”

“…However, all of these atmospheric processes are highly mesoscale and require non-standard meteorological measurements at a high resolution, which are rarely available from regular meteorological networks. To document the spatial and temporal changes at the mesoscale, including the estimation of the basic meteotsunamigenic disturbance parameters (intensity, horizontal gradients, disturbance speed and propagation direction), weather radar observations were found to be quite useful in meteotsunami research (Vilibić et al 2014;Wertman et al 2015;Sibley et al 2016;Linares et al 2019;Shi et al 2020).…”

Temporal and Spatial Impact of Precipitable Water Vapor on GPS Relative Positioning During the Tropical Cyclone Hato (2017) in Hong Kong and Taiwan

“…The spiral band structure in the vicinity of TCs has a breadth of tens of kilometers on average (Subrahmanyam et al., 2018; Yu et al., 2018). The bands propagate outward in the form of waves along the radial direction for a period of several hours (Nolan & Zhang, 2017; Shi et al., 2020). Accordingly, the 2–5 h scale was herein selected.…”

Meteotsunamis Accompanying Tropical Cyclone Rainbands During Hurricane Harvey

“…In contrast, the numerical modeling conducted as part of this study shows that air pressure disturbances accompanying TCRs can initiate and resonantly amplify sea-level anomalies across the wide GOM shelf and in some cases produce meteotsunamis with similar periods O(20 min) and amplitudes O(0.2 m) as surf zone observations (Figures 5 and 6). One potentially important distinction between the modeling conducted by Shi et al (2020) and this current study is the numerical resolution of large gradients in air pressure over short distances. The air pressure disturbances measured during Hurricane Harvey featured sharp changes in pressure over short distances, particularly for the "landfall" scenario where trough and crest wavelengths ranged between 6 and 16 km for the range of simulated forward speeds ( Figure 6).…”