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Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/nhess-2017-397
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
28 Nov 2017
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Natural Hazards and Earth System Sciences (NHESS).
The influence of sea surface temperature on the intensity and associated storm surge of tropical cyclone Yasi: A sensitivity study
Sally L. Lavender, Ron K. Hoeke, and Deborah J. Abbs Climate Science Centre, CSIRO Oceans and Atmosphere, PMB1, Aspendale, VIC, 3195, Australia
Abstract. Tropical cyclones (TCs) cause widespread damage associated with strong winds, heavy rainfall and storm surge. Understanding changes in these characteristics associated with potential future climate scenario sea surface temperatures (SSTs), as well as variations with climate modes, such as the El Niño/Southern Oscillation, is important for mitigating impacts. TC Yasi was one of the most powerful TCs to impact the Queensland coast since records began. Prior to Yasi, the SSTs in the Coral Sea were higher than average by 1–2 °C, primarily due to the 2010/2011 La Niña event. In this study, a conceptually simple sensitivity analysis is performed to gain insight into the influence of SST on the track, size, intensity and potential destructiveness of TC Yasi, including rainfall and storm surge.

In order to assess the ability of a high resolution regional model at simulating TC Yasi, the Weather Research and Forecasting (WRF) model is forced in a control run using atmospheric reanalyses and observed SST data over the period 31st January to 4th February 2013. The model is able to closely simulate the observed track, with the modelled landfall occurring within 50 km and 3-hours of the observed event. Additional simulations are carried out with uniform SST anomalies of between −4 °C and 4 °C applied to the observed SST's over the whole region in 1 degree increments, forming a set of nine simulations. The resulting surface winds and pressure were then used to force a barotropic storm surge model.

An increase in SST results in an increase in intensity, precipitation and destructiveness of the storm, however there is little influence on track prior to landfall. In addition to an increase in precipitation, there is a change in the spatial distribution of precipitation as the SST increases. Decreases in SSTs result in an increase in the radius of maximum winds due to an increase in the asymmetry of the storm, although the radius of gale-force winds decreases. These changes in the TC characteristics also lead to changes in the associated storm surge. Generally, cooler (warmer) SST lead to reduced (enhanced) maximum storm surges. However, the increase in surge reaches a maximum with an increase in SST of 2 °C. Any further increase in SST does not affect the maximum surge but the total area and duration of the simulated surge increases with increasing upper ocean temps. The largest change in storm surge occurs when a negative SST anomaly is applied with a decrease in storm surge height of over 3 m when the SST is reduced by 2 °C.

In summary, increases in SST lead to an increase in the potential destructiveness of TCs, although this relationship is not linear.


Citation: Lavender, S. L., Hoeke, R. K., and Abbs, D. J.: The influence of sea surface temperature on the intensity and associated storm surge of tropical cyclone Yasi: A sensitivity study, Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2017-397, in review, 2017.
Sally L. Lavender et al.
Sally L. Lavender et al.
Sally L. Lavender et al.

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Short summary
This study analyses the influence of sea surface temperature (SST) on the track and intensity of tropical cyclone (TC) Yasi and the associated precipitation and storm surge. A set of regional climate model simulations with SST anomalies varying from +4 °C to −4 °C are used and results used to force a storm surge model. Increases in SST lead to an increase in the potential destructiveness of the TC (intensity, rainfall and storm surge) although this relationship is not linear.
This study analyses the influence of sea surface temperature (SST) on the track and intensity of...
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