Simulation of a torrential rainstorm in Xinjiang and gravity wave analysis

We used a weather research and forecasting model to simulate a torrential rainstorm that occurred in Xinjiang, China during June 16-17, 2016. The model successfully simulated the rainfall area, precipitation intensity, and changes in precipitation. We identified a clear wave signal using the two-dimensional fast Fourier transform method; the waves propagated westwards, with wavelengths of 45-20 km, periods of 50-120 min, and phase velocities mainly concentrated in the -25 m/s to -10 m/s range. The results of wavelet cross-spectral analysis further confirmed that the waves were gravity waves, peaking at 11:00 UTC, June 17, 2016. The gravity wave signal was identified along 79.17-79.93°E, 81.35-81.45°E and 81.5-81.83°E. The gravity waves detected along 81.5-81.83°E corresponded well with precipitation that accumulated in 1 h, indicating that gravity waves could be considered a rainstorm precursor in future precipitation forecasts.