Low-level wind shear: a critical review

Wind shear is the local variation of the wind vector. Significant shear at low levels may be produced by synoptic scale fronts, sea breezes, lowlevel jets and mountain waves. Convective features producing wind shear are the thunderstorm gust front and the squall line. Theoretical and observational background information on the occurrence of low-level wind shear is provided. Aircraft takeoff, approach and landing incidents related to wind shear are cited. Graphs and tables which can aid in the forecasting of low-level wind shear under various conditions are provided. The occurrence of wind shear with synoptic scale systems and with convective systems is described. This paper is intended to be a guide to the forecaster in predicting low-level wind shear and assessing its significance. 1979 NWS (National Weather Service) Library Public Domain 1931

风切变是风矢量的局地变化。低空显著风切变可由天气尺度锋面、海陆风、低空急流与山地波诱发。可产生风切变的对流性天气特征包括雷暴阵风锋与飑线。本资料涵盖了低空风切变发生的理论与观测背景资料。文中列举了与风切变相关的航空器起飞、进近及着陆事故案例。同时提供了可辅助多场景下低空风切变预报的图表与表格。本文阐述了风切变与天气尺度系统、对流系统相伴发生的规律，旨在为预报人员预测低空风切变并评估其影响严重性提供专业指南。本资料为1979年美国国家气象局（National Weather Service, NWS）图书馆公有领域馆藏，编号1931。