Group 1 - The core viewpoint of the articles highlights the unprecedented rainfall and extended rainy season in North China, marking it as the strongest since 1961 [2][6][13] - The North China rainy season began on July 5, 2023, which is 13 days earlier than the average, and lasted for 59 days, significantly longer than the typical 30 days [6][13] - The cumulative rainfall in North China has been exceptionally high, with some areas experiencing rainfall amounts 50% to 200% above the historical average [8][10] Group 2 - The rainfall has led to significant hydrological impacts, with 23 rivers exceeding warning levels, prompting a level IV flood defense response in Sichuan and Shaanxi provinces [1] - The rainfall has caused secondary disasters such as mountain floods and urban waterlogging, while also alleviating drought conditions in some regions [8][10] - The meteorological conditions contributing to this unusual weather pattern include abnormal sea surface temperatures in the equatorial Pacific and strong subtropical high pressure in the western Pacific [15]

Core Insights - The North China rainy season officially ended on September 2, 2023, marking the longest duration and highest cumulative rainfall since 1961, making it the strongest rainy season on record [1][3][19] Summary by Sections Rainy Season Duration and Intensity - The rainy season in North China began on July 5, 2023, which is 13 days earlier than the average, and lasted for 59 days, 29 days longer than usual [3][13] - The intensity of the rainy season was significantly stronger compared to historical averages, with the overall rainfall in North China being the highest since 1961 [3][5] Regional Rainfall Distribution - Since June, the average national rainfall has approached historical levels, but distribution has been uneven, with northern regions experiencing 50% to 200% more rainfall than usual [5][9] - In Tianjin, the average rainfall reached 586.7 mm, which is 40% above the historical average [9] Economic and Environmental Impact - The prolonged rainy season has had dual effects: while it caused flooding and geological disasters in some areas, it also alleviated drought conditions in parts of central and western China, benefiting pasture growth and improving water levels in lakes and wetlands [7][11] - The increased rainfall has affected agriculture, transportation, and tourism, with significant impacts on public perception of weather conditions during peak commuting hours [13][19] Meteorological Factors - The unusual weather patterns are attributed to several factors, including abnormal sea temperatures in the equatorial Pacific and the persistent strength of the subtropical high-pressure system in the western Pacific [14][16] - The geographical features of the Beijing-Tianjin-Hebei region, including the Taihang and Yanshan mountains, contribute to the significant rainfall as warm, moist air is forced to rise, leading to precipitation [16][17] Future Considerations - Meteorological experts note that the duration of the rainy season has shown interdecadal variability, with a trend of increasing duration since 2011, suggesting potential future changes [19]

Core Insights - The North China rainy season has been notably prolonged this year, lasting 55 days as of August 28, compared to the average of 30 days, marking the earliest start since 1961 [1][2][4] - The rainy season has been characterized by increased rainfall, with cumulative precipitation exceeding the normal value by 131% as of August 25 [1][2] - Multiple factors contribute to the extended duration and intensity of the rainy season, including abnormal sea surface temperatures in the equatorial Pacific and a strong subtropical high pressure system [4][5][6] Rainfall Characteristics - There have been 29 significant rainfall events since the onset of the rainy season, with 10 classified as strong and 2 as exceptionally strong [2] - 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 [2][5] Climate Change Implications - The record-breaking rainy season is seen as a local manifestation of global climate system changes, with increasing frequency and intensity of extreme weather events [6][7] - Experts suggest that the duration of the rainy season may continue to exhibit interdecadal variability, with a trend of increasing duration observed since 2011 [6][7]

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].

Core Viewpoint - The northern regions of China are experiencing a prolonged rainy season, with significant rainfall expected to continue in various areas, particularly in the Beijing-Tianjin-Hebei region and surrounding provinces [5][6][7]. Weather Forecast - A yellow rainstorm warning has been issued, predicting heavy rainfall from August 27 to August 28 in regions including Liaoning, Hebei, Beijing, Tianjin, and parts of Sichuan, with localized areas expecting extreme rainfall of 100-150 mm [2][4]. - The rainfall is expected to shift eastward, with the heaviest precipitation anticipated in the Beijing-Tianjin-Hebei area, followed by a further eastward movement towards Liaoning [4][6]. Rainfall Statistics - As of August 25, the rainy season in North China has lasted 52 days, significantly longer than the average duration of 30 days, with an average rainfall of 315.5 mm, which is 131% above the normal value of 136.6 mm [5][6]. Contributing Factors - The excessive rainfall in North China this summer is attributed to several factors, including abnormal sea surface temperatures in the equatorial Pacific, a persistent and strong subtropical high-pressure system, typhoon activity, and geographical influences [6][7]. - The subtropical high has expanded northward due to global warming, facilitating the continuous influx of warm, moist air into northern China, which, combined with cold air from higher latitudes, has resulted in increased precipitation [7]. Geographical Influence - The topography of the Beijing-Tianjin-Hebei region, characterized by the Taihang and Yanshan mountain ranges, enhances rainfall through orographic lift, where moist air is forced to rise, leading to condensation and precipitation [7].