持续时间和累计雨量均创新高 今年华北雨季为何“超长待机”？

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]