Levels of Turbulence Intensity Associated with Transverse Bands in the Upper Troposphere near Japan: Comparison with and without Wave-Like Patterns on Cloud Tops

Turbulence interferes with aircraft operations and occurs frequently near transverse bands. Forecasters from the Japan Meteorological Agency have reported that these transverse bands with wave-like patterns on cloud tops (WPC) tend to generate strong turbulence. We analyzed the rates of turbulence associated with transverse bands in the upper troposphere near Japan at different altitudes, focusing on the presence or absence of WPC. The results show that a significantly higher proportion of turbulence was associated with transverse bands with WPC. Moreover, turbulence occurs above and below these transverse bands. Regarding transverse bands with WPC, moderate turbulence was observed within 4,000 ft (≃ 1.2 km) above and below the cloud, indicating that turbulence area extends over a wide vertical range.