Contribution Quantification to Spring Low‐Level Jets Over the Western Bohai Sea Coast: Insights From Doppler LiDAR Observations, WRF Modeling and EOF Analysis

Abstract Low‐level jets (LLJs), as dynamically significant narrow air currents in the lower troposphere, profoundly influence regional weather and anthropogenic activities. Motivated by persistent LLJs detected through Doppler LiDAR observations during March to April 2021, this study systematically characterizes these LLJs over Juehua Island (western Bohai Sea coast) by integrating high‐resolution Weather Research and Forecasting Model simulations. Based on a 61‐day simulation spanning March to April 2021, this study reveals a notable LLJ occurrence frequency of 25.3%, dominated by two distinct directional modes: southwesterly and northeasterly. The high frequency and pronounced directional dominance of LLJs in this region motivated a systematic investigation combining Empirical Orthogonal Function (EOF) analysis and sensitivity experiments. The LLJ‐favorable synoptic patterns were extracted through EOF analysis of the sea‐level pressure (SLP) field. The northwest‐southeast SLP dipole pattern plays a dominant role, contributing 68% to LLJ formation. Southwesterly and northeasterly LLJs are favored by “high‐southeast, low‐northwest” and its opposite synoptic dipoles, respectively. Sensitivity experiments quantify the contribution of local geography at 21%, collectively accounted for by the Bohai Sea (16%) and the northwestern highlands (5%). Additionally, the Bohai Sea preferentially enhances southwest LLJs, which exhibit lower LLJ heights. In contrast, the northwestern highlands elevate LLJ heights and align LLJ directions with the terrain orientation, resulting in a more clustered wind direction distribution. This study quantified LLJ‐favorable synoptic patterns, Bohai Sea and northwestern high terrain influences. These findings could provide valuable insights for regional LLJ forecasting.