北方多地为何出现极端强降水 气象专家：大气环流与地形增幅效应是背后“推手”

Core Viewpoint - The recent heavy rainfall in northern China, particularly in Beijing and Hebei, is attributed to abnormal atmospheric circulation patterns, with the subtropical high pressure system playing a significant role in the early onset of the rainy season [1][3]. Group 1: Weather Patterns and Impacts - The subtropical high pressure has shifted northward, leading to an influx of warm, moist air into northern China, which has resulted in extreme rainfall events [1][2]. - The average rainfall in the North China region has reached 121 mm, which is nearly 30% higher than the historical average for the same period [2]. - The rainy season in North China began on July 5, 13 days earlier than the historical average, marking the earliest start since 1961 [2][3]. Group 2: Typhoon Influence - Typhoon "Zhu Jie Cao" has been reclassified and is expected to impact eastern China significantly, with strong winds and heavy rainfall predicted in several regions [4]. - The typhoon indirectly affects the rainfall patterns in northern China by altering the atmospheric circulation, which influences the subtropical high pressure's position and intensity [4]. Group 3: Future Weather Forecast - A strong rainfall event is anticipated in northern China, with warnings issued for potential mountain floods and geological disasters due to cumulative rainfall effects [5]. - The overall precipitation trend is expected to weaken, but localized heavy rainfall may still occur [5].