Future australian severe thunderstorm environments. Part I: A novel evaluation and climatology of convective parameters from two climate models for the late twentieth century
Climatology
; Computer simulation
; Parameter estimation
; Thunderstorms
; Atmospheric model
; Commonwealth scientific and industrial researches
; Convective available potential energies
; Convective parameters
; Model climatology
; Spatial resolution
; Twentieth century
; Vertical wind shear
; Climate models
; climate modeling
; climatology
; convective system
; potential energy
; spatial distribution
; spatial resolution
; spatial variation
; thunderstorm
; twentieth century
; wind shear
; Australia
英文摘要:
The influence of a warming climate on the occurrence of severe thunderstorms over Australia is, as yet, poorly understood. Based on methods used in the development of a climatology of observed severe thunderstorm environments over the continent, two climate models [Commonwealth Scientific and Industrial Research Organisation Mark, version 3.6 (CSIRO Mk3.6) and the Cubic-Conformal Atmospheric Model (CCAM)] have been used to produce simulated climatologies of ingredients and environments favorable to severe thunderstorms for the late twentieth century (1980-2000). A novel evaluation of these model climatologies against data from both the ECMWF Interim Re-Analysis (ERA-Interim) and reports of severe thunderstorms from observers is used to analyze the capability of the models to represent convective environments in the current climate. This evaluation examines the representation of thunderstorm-favorable environments in terms of their frequency, seasonal cycle, and spatial distribution, while presenting a framework for future evaluations of climate model convective parameters. Both models showed the capability to explain at least 75% of the spatial variance in both vertical wind shear and convective available potential energy (CAPE). CSIRO Mk3.6 struggled to either represent the diurnal cycle over a large portion of the continent or resolve the annual cycle, while in contrast CCAM showed a tendency to underestimate CAPE and 0-6-km bulk magnitude vertical wind shear (S06). While spatial resolution likely contributes to rendering of features such as coastal moisture and significant topography, the distribution of severe thunderstorm environments is found to have greater sensitivity to model biases. This highlights the need for a consistent approach to evaluating convective parameters and severe thunderstorm environments in present-day climate: an example of which is presented here.
School of Earth Sciences, University of Melbourne, Victoria, Australia; International Research Institute for Climate and Society, The Earth Institute, Columbia University, Palisades, NY, United States
Recommended Citation:
Allen J.T.,Karoly D.J.,Walsh K.J.. Future australian severe thunderstorm environments. Part I: A novel evaluation and climatology of convective parameters from two climate models for the late twentieth century[J]. Journal of Climate,2014-01-01,27(10)