Modeled dependence of wind and waves on ocean temperature in tropical cyclones

Abstract:

A coupled ocean-atmosphere-wave model is used to investigate the sensitivity of surface wind speed and significant wave height to ocean temperature for idealized tropical cyclones (TCs). More intense and larger TCs, with higher waves, form when ocean temperature is increased. The maximum significant wave height increases more than the maximum wind speed for TCs up to hurricane force wind. However, above hurricane force wind the change in maximum wind speed is similar or greater than the change in maximum significant wave height. This can be explained by the wind drag coefficient decreasing as wind speed exceeds hurricane force wind, so that the growth of waves is dampened. The areal footprint of wave height grows considerably more than the maximum as ocean temperature is increased. This suggests a large increase in the surface area of damaging waves generated by TCs may be the dominant impact of a future warmer ocean.