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Teleconnection between the Indian summer monsoon onset and the Meiyu over the Yangtze River Valley

Science china Earth sciences 2008年第7期51卷 1021-1035页

作者： liu yunyun1,2.3 & {2. yihui2.1 chinese academy of Meteorological sciences, beijing 100081, china 2.National Climate Center, beijing 100081, china 3 Graduate University of chinese academy of sciences, beijing 100049, china 1. chinese academy of Meteorological {2. Beijing 100081 China 2. National Climate Center Beijing 100081 China 3. Graduate University of chinese academy of {2. Beijing 100049 China

Based on the Indian and chinese precipitation data and the NCEP-NCAR reanalysis circulation data, the relationship between the Indian summer monsoon (ISM) onset and the Meiyu over the Yangtze River Valley has been discussed by the methods of correlation analysis and composite analysis. The results show that the date of ISM onset over Kerala in the southwestern coast of the Indian Peninsula is about two weeks earlier than the beginning of the Meiyu over the Yangtze River Valley. After the outbreak of ISM, the teleconnection mode sets up from the western coast of India via the Bay of Bengal (BOB) to the Yangtze River Valley and southern Japan. It is different both in time and space from the telecon- nection mode which is from the northwest of India via the Tibetan Plateau to northern china. The for- mer mode is defined as the "south" teleconnection of the Asian summer monsoon, forming in the pe- riod of ISM onset; while the latter mode is called the "north" teleconnection, mainly occurring in the Asian monsoon culminant period. During the process of the "south" teleconnection’s formation, the Asian monsoon circulation has experienced a series of important changes: ISM onset, the northward movement of the south Asia high (SAH), the onset vortex occurrence, the eastward extension of the stronger tropical westerly belt, and the northeastward jump of the western Pacific subtropical high (WPSH), etc. Consequently, since ISM sets up over Kerala, the whole Asian continent is covered by the upper SAH after about two weeks, while in the mid- and lower troposphere, a strong wind belt forms from the Arabian Sea via the southern India, BOB and the South china Sea (SCS), then along the western flank of WPSH, to the Yangtze River Valley and southern Japan. With the northward moving of the subtropical jet streams, the upper westerly jet stream and the low level jet have been coupled ver- tically over east Asia, while the Yangtze River Valley happens to locate in the ascending motion

关键词： Indian summer monsoon (ISM) the Meiyu over the Yangtze River Valley teleconnection mode

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Analysis and Monitoring of Indoor Radon Concentrations of 37 Kindergartens — beijing Municipality, china, 2.2.

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china CDC weekly 2024年第13期6卷 272-276页

作者： Meinan Yao Kuke ding Xiaozhe Tang yunyun Wu Yanchao Song Shuyuan {2. Bin Bai Li Zhang Yongzhong Ma Institute for Radiation Hygiene Protection Beijing Center for Disease Prevention and ControlBeijingChina chinese Center for Disease Control and Prevention BeijingChina Key Laboratory of Radiological Protection and Nuclear Emergency&National Institute for Radiological Protection Chinese Center for Disease Control and PreventionBeijingChina

Introduction:Radon(2.2.n or 2.2.adon)is a radioactive gas emitted from building materials,foundations,and *** are especially susceptible to radon exposure,underscoring the need to assess indoor radon levels in *** study monitored radon concentrations in 37 beijing kindergartens from June to October ***:A random sample of 37 kindergartens was selected from 18 administrative districts in *** indoor radon concentration was measured using the solid track accumulation method,with radon detectors continuously monitored over a 3-month ***:The mean indoor radon level in 37 kindergartens,observed at 2.2.monitoring points,was 84.3 Bq/m^(3),with values varying from 12.9 to {2..5 Bq/m^(3).About 2..2.of points showed radon levels between 100.0 and 2.0.0 Bq/m^(3),while 2.4%exceeded 2.0.0 Bq/m^(3).Notably,radon levels were significantly elevated on the ground floor compared to the upper ***:Indoor radon levels in 37 kindergartens remained below the national standard limit of 300.0 Bq/m^(3) for buildings(GB/T 16146-2.15).Nonetheless,18.9%of the kindergartens exceeded the 100.0 Bq/m^(3) limit set for new *** is advised to improve radon monitoring in kindergartens and consider developing a national standard for maximum permissible radon levels in such facilities.

关键词： Radon limit floor

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Tuning the product selectivity of dimethyl oxalate hydrogenation over WO_(x) modified Cu/SiO_(2. catalysts

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Journal of Energy Chemistry 2024年第10期97卷 128-138,I0004页

作者： Zheng Li Zhuo Ma yihui Li Ziang Zhao Yuan Tan Ziyin liu Xingkun Chen Nian Lei Huigang Wang Wei Lu Hejun Zhu Yunjie {2. Hangzhou Institute of Advanced Studies Zhejiang Normal UniversityHangzhou 311231ZhejiangChina Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina University of chinese academy of {2. Beijing 100049China Shaanxi Key Laboratory of Clean Energy Technology Utilization Yulin BranchDalian National Laboratory For Clean EnergyCASYulin 719199ShaanxiChina State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Product selectivity and reaction pathway are highly dependent on surface structure of heterogeneous *** vapor-phase hydrogenation of dimethyl oxalate(DMO),"EG route"(DMO→methyl glycolate(MG)ethylene glycol(EG)→ethanol(ET))and"MA route"(DMO→MG→methyl acetate(MA))were proposed over traditional Cu based catalysts and Mo-based or Fe-based catalysts,***,tunable yield of ET(93.7%)and MA(72.1%)were obtained through different reaction routes over WO_(x) modified Cu/SiO_(2. catalysts,and the corresponding reaction route was further proved by kinetic study and in-situ DRIFTS *** studies demonstrated that H_(2. activation ability,acid density and Cu-WO_(x) interaction on the catalysts were tuned by regulating the surface W density,which resulted in the different reaction pathway and product ***'s more,high yield of MA produced from DMO hydrogenation was firstly reported with the H_(2. pressure as low as 0.5 MPa.

关键词： Ethanol Dimethyl oxalate Selective hydrogenation Methyl acetate WCu/SiO_(2.catalyst

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The Record-breaking Mei-yu in 2.2. and Associated Atmospheric Circulation and Tropical SST Anomalies

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Advances in Atmospheric sciences 2021年第12期38卷 1980-1993页

作者： yihui ding {2. liu Zeng-Zhen HU National Climate Center China Meteorological AdministrationBeijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China Climate Prediction Center NCEP/NOAACollege ParkMD 20740USA

The record-breaking mei-yu in the Yangtze-Huaihe River valley(YHRV)in 2.2. was characterized by an early onset,a delayed retreat,a long duration,a wide meridional rainbelt,abundant precipitation,and frequent heavy rainstorm *** is noted that the East Asian monsoon circulation system presented a significant quasi-biweekly oscillation(QBWO)during the mei-yu season of 2.2. that was associated with the onset and retreat of mei-yu,a northward shift and stagnation of the rainbelt,and the occurrence and persistence of heavy rainstorm ***,during the mei-yu season,the monsoon circulation subsystems,including the western Pacific subtropical high(WPSH),the upper-level East Asian westerly jet,and the low-level southwesterly jet,experienced periodic oscillations linked with the *** notably,the repeated establishment of a large southerly center,with relatively stable latitude,led to moisture convergence and ascent which was observed to develop *** was accompanied by a long-term duration of the mei-yu rainfall in the YHRV and frequent occurrences of rainstorm ***,two blocking highs were present in the middle to high latitudes over Eurasia,and a trough along the East Asian coast was also active,which allowed cold air intrusions to move southward through the northwestern and/or northeastern *** cold air frequently merged with the warm and moist air from the low latitudes resulting in low-level convergence over the *** persistent warming in the tropical Indian Ocean is found to be an important external contributor to an EAP/PJ-like teleconnection pattern over East Asia along with an intensified and southerly displaced WPSH,which was observed to be favorable for excessive rainfall over YHRV.

关键词： record-breaking mei-yu western Pacific subtropical high quasi-biweekly oscillation Tropical Indian Ocean warming low-level southwesterly jet blocking high

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Atmospheric Circulation and Dynamic Mechanism for Persistent Haze Events in the beijing–Tianjin–Hebei Region

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Advances in Atmospheric sciences 2017年第4期34卷 429-440页

作者： Ping WU yihui ding Yanju {2. College of Atmospheric Science Nanjing University of Information Science and TechnologyNanjing 210044China chinese academy of Meteorological {2. Beijing 100081China National Climate Center Beijing 100081China

In this study, regional persistent haze events（RPHEs） in the beijing–Tianjin–Hebei（BTH） region were identified based on the Objective Identification Technique for Regional Extreme Events for the period 1980–2.13. The formation mechanisms of the severe RPHEs were investigated with focus on the atmospheric circulation and dynamic mechanisms. Results indicated that：（1） 49 RPHEs occurred during the past 34 years.（2. The severe RPHEs could be categorized into two types accor{2. to the large-scale circulation, i.e. the zonal westerly airflow（ZWA） type and the high-pressure ridge（HPR） type. When the ZWA-type RPHEs occurred, the BTH region was controlled by near zonal westerly airflow in the mid–upper *** winds prevailed in the lower troposphere, and near-surface wind speeds were only 1–2.ms^-1. Warm and humid air originating from the northwestern Pacific was transported into the region, where the relative humidity was 70% to 80%, creating favorable moisture conditions. When the HPR-type RPHEs appeared, northwesterly airflow in the mid–upper troposphere controlled the region. Westerly winds prevailed in the lower troposphere and the moisture conditions were relatively weak.（3） Descen{2. motion in the mid-lower troposphere caused by the above two circulation types provided a crucial dynamic mechanism for the formation of the two types of RPHEs. The descen{2. motion contributed to a reduction in the height of the planetary boundary layer（PBL）, which generated an inversion in the lower troposphere. This inversion trapped the abundant pollution and moisture in the lower PBL, lea{2. to high concentrations of pollutants.

关键词： beijing–Tianjin–Hebei region regional persistent haze events atmospheric circulation dynamic mechanism

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Tropospheric biennial oscillation of the western Pacific subtropical high and its relationships with the tropical SST and atmospheric circulation anomalies

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chinese Science Bulletin 2013年第27期58卷 3664-3672页

作者： liu yunyun {2. yihui GAO Hui LI WeiJing National Climate Center China Meteorological Administration

There is the significant period of tropospheric biennial Oscillation(TBO)over East Asian monsoon region at the interannual timescales,which has the important influences on East china *** on a set of reconstructed indices which describes the western Pacific subtropical high(WPSH)objectively,this paper focuses on the TBO component of WPSH,one of the key members of the East Asian Monsoon system,and its relationships with the tropical SST and atmospheric circulation *** is found that(1)As an important interannual component of WPSH,the time series of TBO has the obvious transition in the late1970s,and the variability of the WPSH’s TBO component is more significant after the late 1970s.(2.The time-lag correlations between the WPSH’s TBO and the tropical sea surface temperature(SST)anomalies in several key ocean regions are more significant and have longer correlation duration than the raw *** response of the western boundary index to ENSO is earlier than the intensity index,and the time-lag correlations of them are up to maximum when lagging ENSO by 3–5 months and 5–6months,respectively.(3)In the course of the WPSH’s TBO cycle,the occurrence of the El Ni o-like anomaly in the tropical central-eastern Pacific in winter is always coupled with the weak East Asian winter monsoon,with the most significant enhancing phase of the WPSH’*** contrast,the La Ni a-like anomaly in the central-eastern Pacific in winter is coupled with the strong East Asian winter monsoon,with the most weakening phase of the WPSH’s TBO.(4)The distribution of the tropical SST and atmospheric circulations anomalies are asymmetric in the TBO *** WPSH’s TBO is more significant in the period of the developing El Ni o-like anomaly in central-eastern Pacific than in the period of the developing La Ni a-like ***,during the period of developing El Ni o-like anomaly,more attention should be paid to the interannual component of TBO signal in the short-term climate pre

关键词：西太平洋副热带高压大气环流异常热带海温准两年振荡对流层东亚冬季风短期气候预测东亚季风区

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Environmental and Dynamic Conditions for the Occurrence ofPersistent Haze Events in North china

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Engineering 2017年第2期3卷 266-271页

作者： yihui ding Ping Wu Yanju {2. Yafang Song National Climate Center Beijing 100081 China chinese academy of Meteorological Sdences Beijing 100081 China College of Atmospheric Science Nanjing University o.f lnforrnation Sdence and Technology Nanjing 210044 China

This paper presents a concise summary of recent studies on the long-term variations of haze in Northchina and on the environmental and dynamic conditions for severe persistent haze events. Resultsindicate that haze days have an obviously rising trend over the past 50 years in North china. Theoccurrence frequency of persistent haze events has a similar rising trend due to the continuous riseof winter temperatures, decrease of surface wind speeds, and aggravation of atmospheric stability. InNorth china, when severe persistent haze events occur, anomalous southwesterly winds prevail in thelower troposphere, providing sufficient moisture for the formation of haze. Moreover, North china ismainly controlled by a deep downdraft in the mid-lower troposphere, which contributes to reducing thethickness of the planetary boundary layer, obviously reducing the atmospheric capacity for *** atmospheric circulation and sinking motion provide favorable conditions for the formation andmaintenance of haze in North china.

关键词： North china Persistent haze events Environmental conditions Dynamic conditions

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Decadal northward shift of the Meiyu belt and the possible cause

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chinese Science Bulletin 2009年第24期54卷 4742-4748页

作者： SI Dong ding yihui {2. YanJu College of Atmospheric Science Nanjing University of Information Science and Technology Nanjing 210044 China National Climate Center Beijing 100081 China

The feature of the decadal movement of the Meiyu belt and their association with East Asia atmospheric circulation for the period of 1979―2.07 is examined in this study. It is shown that the Meiyu belt of china has a decadal shift in the late 1990s. There is a remarkable difference between the periods before and after 1999, with the Meiyu belt mainly located to the south of the Yangtze River valley before 1999, but afterward mainly located in the Huaihe River valley. At the same time, a distinctive tropospheric warming and stratospheric cooling trend is found in the mid-latitudes of East Asia, which causes the upper tropospheric pressure surfaces upward bulging and the tropoause elevated in the subtropics and associated widening of the subtropical area over East Asia. Accompanying the subtropics widening, the subtropical westerly jet over East Asia shifts northward and the East Asia tropical Hadley circulation expands poleward, which results in the northward shift of the Meiyu belt.

关键词：年代际变化梅雨带北移亚热带地区 Hadley环流东亚地区原因大气环流

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The impact of meteorological changes from 2.13 to 2.17 on PM2.5 mass reduction in key regions in{2.

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Science china Earth sciences 2019年第12期62卷 1885-1902页

作者： Xiaoye ZHANG Xiangde XU yihui ding Yanju {2. Hengde ZHANG Yaqiang WANG Junting ZHONG chinese academy of Meteorological {2. China Meteorological AdministrationBeijing 100081China National Climate Centre China Meteorological AdministrationBeijing 100081China National Meteorological Center China Meteorological AdministrationBeijing 100081China

In 2.13,china issued the"Action Plan for the Prevention and Control of Air Pollution"("Ten Statements of Atmosphere")and implemented a series of pollution reduction measures from 2.13 to *** key regions of china,the mass concentrations of particulate matter with aerodynamic equivalent diameters less than 2.5μm(PM2.5)have dropped ***,the contributions of meteorological changes to PM2.5 reduction are largely uncertain,which has attracted particular concern from the government and the ***,we investigated the impact of large-scale and boundary layer(BL)meteorological conditions on aerosol pollution and estimated the contributions of meteorological changes to PM2.5 reduction based on in-depth analysis and diagnosis of various observed meteorological elements and an integrated pollution-linked meteorological index(PLAM,which is approximately and linearly related to PM mass concentration).In this study,we found that the meteorological conditions worsened in 2.14 and 2.15 and improved in 2.16 and 2.17 relative to those in 2.13 in key regions in *** 2.17 relative to 2.13,only^5%(approximately 13%of the total PM2.5 decline)of the 39.6%reduction in PM2.5 mass concentrations can be attributed to meteorological changes in the beijing-Tianjin-Hebei(BTH)region,and only^7%(approximately 2.%of the total PM2.5 decline)of the 34.3%reduction can be attributable to meteorological changes in the Yangtze River Delta(YRD)***,the PM2.5 reduction due to meteorological improvement is much lower than the observed PM2.5 reduction in these areas,which indicates that emission reduction during the five-year implementation of the"Ten Statements of Atmosphere"is the dominant factor in the improvement in air *** changes in meteorology and climate are conducive to PM2.5 reduction but do not dominate the substantial improvement in air *** to the above regions,in the Pearl River Delta(PRD)region,the impact of meteorological changes on the

关键词： Quantifying unfavorable meteorological conditions Contribution of Meteorological Conditions to PM2.5 Change Ten Statements of Atmosphere

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快速动脉自旋标记成像在脑胶质瘤中的临床应用价值

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中华放射学杂志 2024年第5期58卷 529-533页

作者：张艳玲徐慕榕徐晓璐丁金立段云云刘亚欧江裕华卓芝政首都医科大学附属北京天坛医院放射科北京100070 军事科学院军事医学研究院卫生勤务与血液研究所北京100850 首都医科大学附属北京天坛医院神经外科北京100070

目的探讨快速动脉自旋标记(ASL)成像应用于脑胶质瘤成像的可行性。方法前瞻性纳入2.2.年5月至2.2.0}2.就诊于首都医科大学附属北京天坛医院的脑胶质瘤患者,所有患者均接受MR快速ASL(扫描时间1 min)和常规ASL(扫描时间4 min 30 s)检查... 详细信息

目的探讨快速动脉自旋标记(ASL)成像应用于脑胶质瘤成像的可行性。方法前瞻性纳入2.2.年5月至2.2.0}2.就诊于首都医科大学附属北京天坛医院的脑胶质瘤患者,所有患者均接受MR快速ASL(扫描时间1 min)和常规ASL(扫描时间4 min 30 s)检查,得到脑血流分数(CBF)图。由2.放射科医师独立对2.序列扫描所得的CBF进行定性(人工判读肿瘤区CBF信号的高低)和定量分析(提取肿瘤实体区和水肿区等区域CBF平均值)。采用Kappa检验对定性评估结果进行一致性分析;采用ICC对定量结果进行一致性分析。结果共纳入脑胶质瘤患者30例。2.医师采用快速ASL判断肿瘤区低灌注、等灌注、高灌注分别为1、6、2.例和0、5、2.例;采用常规ASL判断肿瘤区低灌注、等灌注、高灌注均为0、9、2.例;快速ASL与常规ASL定性分析的一致性均较高(Kappa分别为0.830、0.850)。定量分析显示,快速ASL与常规ASL测量脑不同部位的CBF值具有较高一致性(ICC为0.940~0.994)。结论快速ASL可替代常规ASL用于脑胶质瘤组织灌注评估,有助于胶质瘤的临床诊断。

关键词：磁共振成像快速动脉自旋标记脑胶质瘤灌注成像

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