截至8月28日，已持续55天 今年华北雨季为何偏长

Core Viewpoint - The North China rainy season has been notably prolonged this year, lasting 55 days as of August 28, which is significantly longer than the average duration of 30 days, influenced by various climatic factors [1][2][4]. Summary by Relevant Sections Rainy Season Characteristics - The rainy season in North China began on July 5, 13 days earlier than the average start date of July 18, marking the earliest onset since 1961 [2][5]. - As of August 25, the cumulative rainfall in the monitoring area was 131% above the normal seasonal value [2]. Rainfall Events - There have been 29 significant rainfall events since the onset of the rainy season, with 10 classified as strong and 2 as exceptionally strong [3]. - Notable rainfall amounts include over 250 mm in certain areas, with specific locations like Beijing's Miyun District recording 573.5 mm and Baoding in Hebei reaching 605.8 mm [3]. Influencing Factors - The prolonged rainy season is attributed to several factors, including abnormal sea temperatures in the equatorial Pacific, a strong and shifted subtropical high-pressure system, typhoon activity, and geographical features [5][6]. - The subtropical high-pressure system has been particularly strong and has shifted northward, facilitating the influx of warm, moist air from the south [6]. Climate Change Context - The record-breaking rainy season is seen as a local manifestation of global climate change, with increasing frequency and intensity of extreme weather events [7][8]. - Experts suggest that while the rainy season's duration has shown an increasing trend since 2011, it is too early to definitively conclude that this "warming and wetting" trend will continue [7][8].