Future changes in tropical cyclone activity projected by multi-physics and multi-SST ensemble experiments using the 60-km-mesh MRI-AGCM

Hiroyuki Murakami,Eiki Shindo,Ryo Mizuta

doi:10.1007/s00382-011-1223-x

Abstract

Uncertainties in projected future changes in tropical cyclone (TC) activity are investigated using future (2075–2099) ensemble projections of global warming under the Intergovernmental Panel on Climate Change (IPCC) A1B scenario. Twelve ensemble experiments are performed using three different cumulus convection schemes and four different assumptions for prescribed future sea surface temperatures (SSTs). All ensemble experiments consistently project significant reductions in global and hemispheric TC genesis numbers as well as reductions in TC frequency of occurrence (TCF) and TC genesis frequency (TGF) in the western North Pacific, South Indian Ocean, and South Pacific Ocean. TCF and TGF are projected to increase over the central Pacific which is consistent with the findings of Li et al. (2010). Inter-experimental variations of projected future changes in TGF and TC genesis number are caused mainly by differences in large-scale dynamical parameters and SST anomalies. Thermodynamic parameters are of secondary importance for variations in TGF and TC genesis number. These results imply that differences in SST spatial patterns can cause substantial variations and uncertainties in projected future changes of TGF and TC numbers at ocean-basin scales.

Highlights

Projections of the potential impacts of global warming on regional tropical cyclone (TC) activity are important for estimations of potential future socio-economic losses
Li et al (2010) examined the sensitivity of future TC projections with various global highresolution (40–50-km-mesh) models and various future sea surface temperatures (SSTs) patterns. We extend this methodology by examining the same model but with different physical packages, forced with different groups of future SST patterns derived from eighteen Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) coupled models
The projected global TC numbers are significantly reduced in the future climate projections by amounts ranging from 5 to 35%

Summary

Introduction

Projections of the potential impacts of global warming on regional tropical cyclone (TC) activity are important for estimations of potential future socio-economic losses Both theory (Emanuel 1987) and modelling studies (Knutson et al 2010) suggest that the TC intensity could increase with global warming (IPCC 2007); projected changes in the TC genesis number have varied considerably, especially at the ocean-basin scale (IPCC 2007; Emanuel 2008; Zhao et al 2009; Knutson et al 2010). We extend this methodology by examining the same model but with different physical packages, forced with different groups of future SST patterns derived from eighteen IPCC Fourth Assessment Report (AR4) coupled models

Methods

Results

Conclusion