Characteristics of Supercells in the Rainband of Numerically Simulated Cyclone Sidr

Abstract

Cyclone Sidr had an intense rainband east of the cyclone center. The rainband exhibited two strong convective lines (band axes) composed of convective cells. To study the characteristics of the convective cells, a simulation was performed at 1-km resolution by using a cloud-resolving model. In both band axes, some cells showed the characteristic structure of a supercell. Supercells within the outer axis had stronger updraft, more intense precipitation, and a longer lifetime than those of the inner axis. The values of the CAPE and helicity are different in the strong vertical shear environment of the inner and outer axes. A large moisture flux was present throughout the troposphere on the east side of the outer axis. On the other hand, the upper level west of the inner axis was relatively dry. These are additional factors affecting the differences in cell characteristics in the two band axes.

Recurvature and movement processes of tropical cyclones over the Bay of Bengal

“…The Cloud Resolving Storm Simulator (CReSS) is a three‐dimensional terrain‐following cloud‐resolving model developed at Nagoya University, Japan (Tsuboki and Sakakibara, 2002); this model can perform numerical simulations of different weather phenomena (i.e., Wang et al ., 2005; Maesaka et al ., 2006; Ohigashi and Tsuboki, 2007; Yamada, 2008; Rafiuddin et al ., 2013) with resolutions on the order of a few tens of meters to a few kilometers. The CReSS model has also successfully simulated TCs (i.e., Tsujino et al ., 2020; Tsujino and Tsuboki, 2020; Wang et al ., 2020), including TCs and monsoon depressions over the BoB (Akter and Tsuboki, 2010; 2012; Fujinami et al ., 2020). The model architecture supports a horizontal curvilinear Arakawa “C” grid and a Lorenz grid in the vertical direction.…”

Multiscale Processes Leading to Supercells in the Landfalling Outer Rainbands of Hurricane Katrina (2005)

“…Idealized simulations by McCaul and Weisman (1996) initiated storms with a warm bubble within a horizontally homogeneous environment derived from a TC tornado proximity sounding. A recent simulation of an Indian Ocean TC by Akter and Tsuboki (2010) contained supercells in the outer rainbands, as did more idealized simulations by Morin et al (2010). Mashiko et al (2009) simulated the outer rainband of a Japanese typhoon, but were more focused on modeling down to the tornado scale (the minimum horizontal grid spacing was 50 m).…”