Dependence of tropical cyclone intensification rate on sea‐surface temperature

Abstract

The dependence of tropical cyclone intensification rate on the sea-surface temperature (SST) is examined in the prototype problem for tropical cyclone intensification on an fplane using a three-dimensional, non-hydrostatic numerical model. The effects of changing the SST are compared with those of changing the latitude examined in a recent article. It is found that the dependence of intensification rate on latitude is largest when the SST is marginal for tropical cyclone intensification (26 • C) and reduces in significance as the SST is increased. Further, at a given latitude, intensification begins earlier and the rate of intensification increases with increasing SST, on account of a significant increase of surface moisture fluxes from the warmer ocean. These higher fluxes result in higher values of near-surface moisture and equivalent potential temperature, leading to a larger radial gradient of diabatic heating rate in the low to middle troposphere above the boundary layer. This larger radial gradient leads to a stronger overturning circulation, which in turn leads to a stronger radial import of absolute angular momentum surfaces and therefore more rapid spin-up. These arguments invoke the classical axisymmetric spin-up mechanism. Non-axisymmetric issues are touched upon briefly.

Mean radiosonde soundings for the Australian monsoon/cyclone season

“…Taken together, the results of Črnivec et al () and the present study indicate that tropical cyclone intensification rate is sensitive to both the environmental sounding used and the SST.…”

“…In a recent paper we showed that the intensification rate depends strongly on the SST (Črnivec et al , ) so that, for example, a 1° increase in SST when using the Willis Island sounding would be expected to significantly elevate the intensification rate. In that paper we showed that a larger SST leads to an increase in the surface moisture fluxes, which, in turn, result in higher values of near‐surface moisture, equivalent potential temperature and, most significantly, to a larger radial gradient of diabatic heating rate in the lower to mid troposphere.…”

“…The calculations are performed using the three‐dimensional version of the non‐hydrostatic, time‐dependent, state‐of‐the‐art, Bryan cloud model (CM1) as configured in Črnivec et al (). In brief, the domain is 3005 × 3005 km in size with 570‐grid points in each horizontal direction.…”

A numerical study of deep convection in tropical cyclones

“…() and C̆rnivec et al . (), except that a larger inner grid‐mesh region with constant grid spacing is used here. Specifically, the outer domain is 1500 × 1500 km 2 in size, with variable spacing increasing to 10 km near the domain boundaries.…”

Remote Thermodynamic Impact of the Kuroshio Current on a Developing Tropical Cyclone Over the Western North Pacific in Boreal Fall

“…Of course, there have been numerous studies that discussed the interaction between the warm ocean and an overlying TC (e.g., Chan et al, 2001;Cione & Uhlhorn, 2003;Crnivec et al, 2016;Shay et al, 2000;Wu et al, 2007). Of course, there have been numerous studies that discussed the interaction between the warm ocean and an overlying TC (e.g., Chan et al, 2001;Cione & Uhlhorn, 2003;Crnivec et al, 2016;Shay et al, 2000;Wu et al, 2007).…”