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A wavelet‐based analysis of convective organization in ICON large‐eddy simulations
Author(s) -
Brune Sebastian,
Kapp Florian,
Friederichs Petra
Publication year - 2018
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.3409
Subject(s) - convection , convective available potential energy , wavelet , large eddy simulation , meteorology , squall line , geology , physics , turbulence , computer science , artificial intelligence
Wavelet spectra of rain rates are used to characterize convective organization in high‐resolution simulations (horizontal grid spacing 156 m) with the large‐eddy model ICON‐LEM over Germany. Scattered convection takes place on scales between 1.2 and 4.8 km, while organized structures like supercells or mesoscale convective systems act on scales above 4.8 km. Organization of convection within squall lines is visible in the spectra as spectral energy is increased in certain directions. We further investigate the dynamical properties that relate to convective organization, and highlight the role of parameters such as CAPE and wind shear. Preferred spatial scale, average convective rain rate and anisotropy as inferred from the wavelet spectra are important characteristics to quantify convective organization. They are used to introduce a wavelet‐based organization index (WOI). Compared with other indices for convective organization, WOI does not require the definition of objects. Using the WOI we are able to distinguish organized from non‐organized convection.