Meteotsunami generation by tropical cyclone rainbands: nearshore effects
of rainband dynamics and storm surge
Abstract
During tropical cyclones, meteotsunami waves can be triggered by
atmospheric disturbances accompanying tropical cyclone rainbands (TCRs).
Due to a paucity of high resolution field data along open coasts during
these extreme events, relatively little is known about meteotsunami
generation by TCRs and the coastal impact of these wave phenomena. Here
we link high-resolution field measurements of sea-level and air pressure
from Hurricane Harvey (2017) with a numerical model to show that large
drops in air pressure accompanying trains of very narrow TCRs can
initiate meteotsunami O(40 cm) in height along open coasts distant from
the storm center (>200 km). The resonant-amplification and
propagation of meteotsunami generated by pressure forcing is highly
dependent on oceanographic (storm surge, bathymetry, and coastal
morphology) and atmospheric factors (variable TCR forward speed, TCR
path of translation). We discover that meteotsunami hazard can extend
several days before and after hurricane landfall, and that meteotsunami
are more ubiquitous along the open coast than tidal gauge records
suggest, likely due to the highly-localized propagation and inherent
structure of TCRs. This combined field and numerical study identifies
the potential, but sometimes highly localized conditions necessary, for
meteotsunami to modify storm processes (e.g., overwash, beach erosion)
and serve as a coastal flood hazard during hurricane impact.