Impact of Stochastic Physics and Model Resolution on the Simulation of Tropical Cyclones in Climate GCMs
Open Access
- 1 June 2021
- journal article
- research article
- Published by American Meteorological Society in Journal of Climate
- Vol. 34 (11), 4315-4341
- https://doi.org/10.1175/jcli-d-20-0507.1
Abstract
The role of model resolution in simulating geophysical vortices with the characteristics of realistic tropical cyclones (TCs) is well established. The push for increasing resolution continues, with general circulation models (GCMs) starting to use sub-10-km grid spacing. In the same context it has been suggested that the use of stochastic physics (SP) may act as a surrogate for high resolution, providing some of the benefits at a fraction of the cost. Either technique can reduce model uncertainty, and enhance reliability, by providing a more dynamic environment for initial synoptic disturbances to be spawned and to grow into TCs. We present results from a systematic comparison of the role of model resolution and SP in the simulation of TCs, using EC-Earth simulations from project Climate-SPHINX, in large ensemble mode, spanning five different resolutions. All tropical cyclonic systems, including TCs, were tracked explicitly. As in previous studies, the number of simulated TCs increases with the use of higher resolution, but SP further enhances TC frequencies by ~30%, in a strikingly similar way. The use of SP is beneficial for removing systematic climate biases, albeit not consistently so for interannual variability; conversely, the use of SP improves the simulation of the seasonal cycle of TC frequency. An investigation of the mechanisms behind this response indicates that SP generates both higher TC (and TC seed) genesis rates, and more suitable environmental conditions, enabling a more efficient transition of TC seeds into TCs. These results were confirmed by the use of equivalent simulations with the HadGEM3-GC31 GCM.Keywords
This publication has 101 references indexed in Scilit:
- Dynamical Downscaling Projections of Twenty-First-Century Atlantic Hurricane Activity: CMIP3 and CMIP5 Model-Based ScenariosJournal of Climate, 2013
- A stochastic parametrization for deep convection using cellular automataQuarterly Journal of the Royal Meteorological Society, 2013
- Developing versus Nondeveloping Disturbances for Tropical Cyclone Formation. Part II: Western North PacificMonthly Weather Review, 2012
- Developing versus Nondeveloping Disturbances for Tropical Cyclone Formation. Part I: North AtlanticMonthly Weather Review, 2012
- Uncertainty in weather and climate predictionPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2011
- Self-Stratification of Tropical Cyclone Outflow. Part I: Implications for Storm StructureJournal of the Atmospheric Sciences, 2011
- Modelling climate change: the role of unresolved processesPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2005
- Low frequency variability of tropical cyclone potential intensity 1. Interannual to interdecadal variabilityJournal of Geophysical Research: Atmospheres, 2002
- Comment on “Can existing climate models be used to study anthropogenic changes in tropical cyclone climate”Geophysical Research Letters, 1992
- Can existing climate models be used to study anthropogenic changes in tropical cyclone climate?Geophysical Research Letters, 1990