调控华北沙尘日数年代际变化的大气环流及其近期预估  

Atmospheric modulation of the interdecadal variation in dust days over North China and its near-term projections

作　　者：宁淑畅 宋晓蕾 霍芊伊 尹志聪[1,2] NING Shuchang;SONG Xiaolei;HUO Qianyi;YIN Zhicong(State Key Laboratory of Climate System Prediction and Risk Management/Key Laboratory of Meteorological Disaster,Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing 210044,China;School of Atmospheric Sciences,Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学气候系统预测与变化应对全国重点实验室/气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心,江苏南京210044 [2]南京信息工程大学大气科学学院,江苏南京210044

出　　处：《大气科学学报》2025年第2期229-239,共11页Transactions of Atmospheric Sciences

基　　金：国家自然科学基金项目(42088101)。

摘　　要：沙尘天气对社会经济与生态环境产生不利影响,认识其年代际变化并探索其未来态势具有重要意义。本文使用站点资料与再分析数据,研究了调控1961—2020年3—4月华北地区沙尘日数年代际变化的关键大气环流,并利用CMIP6和CESM-LE两套模式数据预估其近期变化。结果表明,华北地区沙尘日数在20世纪80年代末90年代初发生了显著突变,高发时期(1961—1989年,P1)的沙尘日数大约是低发时期(1992—2020年,P2)的3.5倍。这一变化受到由西欧平原东传至乌拉尔山及蒙古高原的波列系统(西欧低压-乌拉尔山高压-蒙古低压异常,anomaly of geopotential height in Western Europe,Ural Mountains and Mongolia,简称EUM)影响。相较于P2时期,P1时期波列较强,乌拉尔山地区位势高度升高,其东部异常偏北气流有利于冷空气南下。蒙古地区位势高度降低,显著的蒙古气旋异常为华北地区沙尘天气提供了动力条件。同时沙源地上空水汽辐散,不利于降水。EUM指数具有与华北地区沙尘日数较为一致的年代际变化特征,对后者未来变化有一定的指示作用。但不同模式对EUM年代际变化的模拟能力差异较大。通过筛选能够再现EUM年代际减弱特征的最优模式集合,发现在高排放情境下,未来近期(2021—2050年,P3)EUM显著增强,有利于华北地区沙尘天气增加。Dust weather has significant socioeconomic and environmental impacts and pose serious threats to human health.Understanding its interdecadal variability and future changes is of great importance.In this study,station observations and reanalysis datasets are used to investigate the key atmospheric circulation patterns governing the interdecadal variability of dust days in North China from March to April during the period 1961-2020.Additionally,two model datasets,CMIP6 and CESM-LE,are employed to project future changes in dust days.Results show a significant shift in the number of dust days in North China at the transition between the late 1980s and early 1990s.During the high-incidence period(1961 to 1989,P1),the average number of dust days was approximately 3.5 times as high as that in the low-incidence period(1992 to 2020,P2).This variation is closely linked to an atmospheric circulation pattern associated with a wave train extending eastward from the western European Plain to the Ural Mountains and the Mongolian Plateau(EUM).Compared to P2,the wave train was more pronounced during P1,with an increased meridional extent of atmospheric circulation over mid-and high-latitude Eurasia.At the 500 hPa,the geopotential height field exhibited significant negative,positive,and negative anomalies over western Europe,the Ural Mountains,and the Mongolian Plateau,respectively.The intensified blocking high over the Ural Mountains,along with the deepened Mongolian low,strengthened the northerly winds east of the Ural Mountains and enhanced the pressure gradient force at mid-latitudes near the surface,facilitating the southward transport of cold air.Simultaneously,the intensified Mongolian cyclone,characterized by strong winds and unstable stratification,promoted dust uplift and transport.Moreover,water vapor divergence over the dust source regions suppressed precipitation,further favoring dust generation.The EUM index exhibits interdecadal variability highly consistent with the number of dust days in North China,making it a va

关 键 词：沙尘日数 年代际变化 影响机制 模式评估 近期预估 

分 类 号：P426.4[天文地球—大气科学及气象学]