Contributions of Surface Sensible Heat Fluxes to Tropical Cyclone. Part I: Evolution of Tropical Cyclone Intensity and Structure

Abstract

The contributions of surface sensible heat fluxes (SHX) to the evolution of tropical cyclone (TC) intensity and structure are examined in this study by conducting cloud-resolving simulations. Results suggest that although the peak values of SHX could account for nearly 30% of those of the total surface latent and sensible heat fluxes, the impact of SHX on TC intensification is nonetheless not distinct. However, the TC size shows great sensitivity to the SHX that the storm is shrunk by over 20% after removing the SHX.A potential temperature budget analysis indicates that the adiabatic cooling accompanying the radial inflow is largely balanced by the transfer of sensible heat fluxes rather than the entrainment of subsiding air from aloft. If there is upward transfer of SHX from underlying ocean so that the near-surface potential temperature decreases upward, the SHX will play a vital role; instead, if the upward SHX are absent so that the potential temperature increases upward near the surface, the downward sensible heat fluxes become the dominant contributor to warm the inflow air. The changes in TC size are found to be primarily caused by the rainband activities. The SHX help maintain high convective available potential energy as well as the cold pool feature outside the eyewall, thus being crucial for the growth of outer rainbands. If without upward transport of SHX, the outer-rainband activities could be largely suppressed, thereby leading to a decrease of the TC size.

Simulated Sensitivity of Tropical Cyclone Size and Structure to the Atmospheric Temperature Profile

“…10b). A similar process was also noted in Ma et al (2015). In contrast, the negative SH fluxes in W3 produce a temperature minimum near the RMW and a strong, positive-radial temperature gradient beyond 100 km that may be constraining the radial inflow in the boundary layer.…”

Effect of the Eyewall Cold Pool on the Inner Rainband of a Tropical Cyclone

“…This study discusses the formation of the ECP and the mechanism by which it triggers the inner rainbands, using numerical simulations of idealized TCs with the CM1 model. There is a clear cold pool just outside the eyewall at low levels, which has been found in some previous numerical studies (Akter & Tsuboki, ; Chen et al, ; Ma et al, ; Moon & Nolan, ; Sawada & Iwasaki, ; Williams, ). The ECP is related to the TC intensity.…”

Sensitivity of the Simulated Tropical Cyclone Intensification to the Boundary‐Layer Height Based on a K‐Profile Boundary‐Layer Parameterization Scheme

“…Three domains are configured with dimensions of 220 × 220, 163 × 163, and 202 × 202 and horizontal resolutions of 15, 5, and 1.67 km, respectively. As in Ma, Fei, Huang, et al (2015a), there are 31 levels distributed as default in the vertical direction, with 10 levels being placed below~2 km. The lowest half model level is roughly at a height of 30 m. The microphysical processes are parameterized using the Lin scheme (Lin et al, 1983).…”

“…Note that there are some important differences among these schemes, including the handling of the turbulent Prandtl number, diffusion above the boundary layer, and specification of the critical bulk‐Richardson number (Bu et al, ). Although the K‐profile parameterization scheme has its limitations as cautioned by Kepert (), it has been proved to work well in modeling the intensity and structure of tropical cyclones (e.g., Ma et al, ; Ma, Fei, Huang, et al, ; Ma, Fei, Cheng, et al, ; Nolan, Zhang, et al, ; Nolan, Stern, et al, ; Zhang et al, ), and performs satisfactorily in the HWRF model (Gopalakrishnan et al, ; Zhang et al, , ). As a typical K‐profile parameterization scheme, the YSU scheme is chosen to parameterize boundary‐layer processes in this study.…”