摘要
The impact of vertical resolution on the simulation of Typhoon Lekima(2019)is investigated using the Weather Research and Forecasting(WRF)model version 3.8.1.Results show that decreasing vertical grid spacing from approximately 1000 m to 100 m above 1 km height barely influences the simulated track.However,significant differences are found in the simulated tropical cyclone(TC)structure.The simulation with the coarsest vertical resolution shows a clear double warm-core structure.The upper warm core weakens and even disappears with the increase of vertical resolution.A broader eye and a more slantwise eyewall are observed with the increase of vertical resolution due to the vertically extended lower-level and upper-level outflow,which likely results in a weaker subsidence.Vertical grid convergence is evaluated with the simulated kinetic energy(KE)spectra.As the vertical grid spacing becomes finer than 200 m,convergent KE spectra are found in both the free atmosphere and the outer core of the TC.However,sensitivity tests reveal that the grid convergence is sensitive to the choice of the planetary boundary layer scheme.
基金
sponsored by the Research Program from Science and Technology Committee of Shanghai(No.19dz1200101)
the National Key Research and Development Program of China(No.2016YFE0109700)
the National Natural Science Foundation of China(Grant No.42075012).
