Investigation of Intense Precipitation from Tropical Cyclones during the 21st Century by Dynamical Downscaling of CCSM4 RCP 4.5

Abstract

In this article, a dynamical downscaling (DD) procedure is proposed to downscale tropical cyclones (TCs) from a general circulation model, with the goal of investigating inland intense precipitation from these storms in the future. This DD procedure is sequential as it is performed from the large scale to the small scale within a one-way nesting modeling framework with the Weather Research and Forecasting (WRF) model. Furthermore, it involves a two-step validation process to ensure that the model produces realistic TCs, both in terms of their general properties and in terms of their intense precipitation statistics. In addition, this procedure makes use of several algorithms such as for the detection and tracking of TCs, with the objective of automatizing the DD process as much as possible so that this approach could be used to downscale massively many climate projections with several sets of model options. The DD approach was applied to the Community Climate System Model (CCSM) version 4 using Representative Concentration Pathway (RCP) 4.5 during the period 2005–2100, and the resulting TCs and their intense precipitation were examined.

Sensitivity of simulating Typhoon Haiyan (2013) using WRF: the role of cumulus convection, surface flux parameterizations, spectral nudging, and initial and boundary conditions

“…In a two-way nesting configuration, both domains are run simultaneously and interact with each other, so that the highest-possible-resolution information produced by the innermost domain affects the solutions over the overlapping area of the coarser domains. The input from the coarse outer domain is introduced through the boundary of the fine inner domain, while feedback to the coarse domain occurs all over the inner domain interior, as its values are replaced by combination of fine inner domain values (Alaka et al, 2022;Mure-Ravaud et al, 2019;Harris and Duran, 2010). We have used two-way nesting in the sensitivity runs, rather than oneway nesting, following recommended practice and previous studies that looked at sensitivities to physics parameterizations in WRF (Wu et al, 2019;Biswas et al, 2014;Li and Pu, 2009;Parker et al, 2017;Spencer et al, 2012;Bopape et al, 2021), studies that simulated Typhoon Haiyan in the Philippines (Li et al, 2018;Nakamura et al, 2016), and TC cases in other basins (Parker et al, 2018;Mittal et al, 2019;Reddy et al, 2021), among others.…”