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The source of Double ITCZ induced by the SST bias over the tropical western Pacific as reflected in CAS-ESM2 Model

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Science China Earth sciences 2024年第5期67卷 1604-1615页

作者： Jinning TONG Fei ZHENG Jiangbo JIN Ruowen YANG Jiang ZHU Qingcun ZENG department of atmospheric sciences Yunnan UniversityKunming 650091China International Center for Climate and Environment Science Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

“Double ITCZ”is a common precipitation bias over the tropical Pacific in current climate models and Earth system models,but the reasons for its formation are still worth exploring and *** this study,we adopted the second version of Chinese Academy of sciences Earth System Model(CAS-ESM2),by comparing a set of sea surface temperature(SST)bias correction experiments over the tropical Pacific,to explore the possible mechanism of SST bias on inducing the“Double ITCZ”from the perspective of the climatic annual mean bias in the coupled *** revealed that the simulated climatic annual mean SST bias over the tropical Pacific can affect the bias of latent heat flux through the saturation specific humidity,and the bias of latent heat flux can further affect that of vertical velocity of humid air by the condensation release mechanism,and finally modulate the simulated bias in ***,through the inter-comparison between different experiments,it is found that the source of Double ITCZ might mainly come from the annual mean SST bias over the tropical western Pacific through the proposed air-sea coupled process of“SST-saturated specific humidity-latent heat flux-vertical velocity-precipitation”,indicating a possible way on reducing the couple biases in models over the tropical Pacific to improve the accuracy of CAS-ESM2 for climate simulation.

关键词： SST bias Double ITCZ Nudging SST CAS-ESM2

Distribution and Formation Causes of PM_(2.5) and O_(3) Double High Pollution Events in China during 2013–20

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Advances in atmospheric sciences 2024年第6期41卷 1235-1250,I0004-I0021页

作者： Zhixuan TONG Yingying YAN Shaofei KONG Jintai LIN Nan CHEN Bo ZHU Jing MA Tianliang ZHAO Shihua QI department of atmospheric Science School of Environmental SciencesChina University of GeosciencesWuhan 430074China State Key Laboratory of atmospheric Boundary Layer Physics and atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Research Centre for Complex Air Pollution of Hubei Province Wuhan 430074China Laboratory for Climate and Ocean–Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking UniversityBeijing 100871China Eco-environmental Monitoring Centre of Hubei Province Wuhan 430074China Key Laboratory of atmospheric Chemistry China Meteorological AdministrationBeijing 100081China School of atmospheric Physics Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Biogeology and environmental Geology China University of GeosciencesWuhan 430074China

Fine particulate matter(PM_(2.5))and ozone(O_(3))double high pollution(DHP)events have occurred frequently over China in recent years,but their causes are not completely *** this study,the spatiotemporal distribution of DHP events in China during 2013–20 is *** synoptic types affecting DHP events are identified with the Lamb–Jenkinson circulation classification *** meteorological and chemical causes of DHP events controlled by the main synoptic types are further *** show that DHP events(1655 in total for China during 2013–20)mainly occur over the North China Plain,Yangtze River Delta,Pearl River Delta,Sichuan Basin,and Central *** occurrence frequency increases by 5.1%during 2013–15,and then decreases by 56.1%during 2015–*** main circulation types of DHP events are“cyclone”and“anticyclone”,accounting for over 40%of all DHP events over five main polluted regions in China,followed by southerly or easterly flat airflow types,like“southeast”,“southwest”,and“east”.Compared with non-DHP events,DHP events are characterized by static or weak wind,high temperature(20.9℃ versus 23.1℃)and low humidity(70.0%versus 64.9%).The diurnal cycles of meteorological conditions cause PM_(2.5)(0300–1200 LST,Local Standard Time=UTC+8 hours)and O_(3)(1500–2100 LST)to exceed the national standards at different periods of the DHP *** pollutant conversion indices further indicate the rapid secondary conversions during DHP events,and thus the concentrations of NO_(2),SO_(2) and volatile organic compounds decrease by 13.1%,4.7%and 4.4%,*** results of this study can be informative for future decisions on the management of DHP events.

关键词： double high pollution events PM_(2.5) ozone spatiotemporal distribution meteorological causes chemical composition characteristics

Anomalies of Precipitation over China on Days with Tropical Cyclone Activity over the Bay of Bengal: Role of Moisture Transport

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Journal of Meteorological Research 2024年第2期38卷 368-382页

作者： Na WEI Ying LI Xiaoting FAN Nanjing Joint Institute for atmospheric sciences Nanjing 210041 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 department of atmospheric and Oceanic sciences and Institute of atmospheric sciences Fudan UniversityShanghai 200433

Tropical cyclones over the Bay of Bengal(BoBTC)affect the precipitation over China,with distinct seasonal and daily *** study quantitatively examines the daily standardized precipitation anomalies(SPAs)over China on the days with BoBTC activities(storm-days)and related circulations,based on rainfall measurements at surface meteorological stations and ECMWF reanalysis data on a 0.25°×0.25°resolution during *** positive SPA is found over the stations in the two adjacent regions around BoB(Southwest China in May/November and southern Tibetan Plateau in October)and three distant regions(Southeast China and the northeastern boundary of the Qinghai-Tibet Plateau in May,and central North China in October).The SPA distributions are remarkably consistent with the integrated water vapor transport(IVT)*** IVT is found associated with the interaction between southwesterly(southerly)of the BoBTC circulation and low-level monsoonal flow in May(midlevel westerly in winter months).The probabilities of extreme precipitation(EP)occurrences over the above regions all increase on *** adjacent regions,EP is significantly correlated with the northward IVT anomalies to the east of BoBTC circulation,which strengthen the water vapor input through the southern *** IVT anomalies are stronger in May,benefited by the deep monsoonal southwesterlies than those in *** distant regions,EP is more closely related to the IVT anomaly extending back from *** moisture from BoB concentrates along a local low-level convergence line over Southeast China,being further facilitated by coexistence of the BoBTC depression and midlevel westerly trough in *** results highlight the interactions between BoBTCs and local weather systems that influence the general precipitation anomalies and occurrence of EP over China,especially over distant regions.

关键词： tropical cyclone Bay of Bengal precipitation anomaly moisture transport

Quantitative estimation of global mean precipitation throughout the Phanerozoic era

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Science China Earth sciences 2024年第5期67卷 1616-1624页

作者： Xiujuan BAO Yongyun HU Laboratory for Climate and Ocean-atmospheric Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking UniversityBeijing 100871China

Quantitatively estimating the global mean precipitation(GMP)throughout Earth's history is crucial for enhancing our understanding of long-term climate evolution and the hydrological ***,currently there is no established methodology for estimating global mean ***,we present the first study that estimates GMP in the Phanerozoic *** relationship between GMP and global mean surface temperature(GMST)is investigated by analyzing data from 23 models in the Coupled Model Intercomparison Project phase 6(CMIP6).The result reveals consistent and significant impact of temperature on precipitation,with a sensitivity range of 2–3%K^(-1).Additionally,we propose a method for accessing latitudinal variations in precipitation caused by land area distributions and paleo-Koppen climatic *** climatic belts are determined based on geological indicators such as coals,evaporites,and glacial *** GMP is thus quantitatively estimated by combining variations in GMST,land area distributions,and paleo-koppen climatic belts,spanning from 540 Ma to the present *** quantitative GMP curve demonstrates fluctuations in GMP about 500 mm yr^(-1),with values ranging from 948 to1442 mm yr-1over the Phanerozoic *** curve aligns closely with findings derived from numerical *** presented paleoprecipitation variations facilitate a more comprehensive understanding of the interconnected geological and paleoclimatic developments.

关键词： Paleoprecipitation Paleoclimate K?ppen climatic belts Global mean precipitation Hydrological cycle

A new portable open-path instrument for ambient NH_(3) and on-road emission measurements

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Journal of environmental sciences 2024年第2期136卷 606-614页

作者： Wenhao Dai Shanshan Wang Sanbao Zhang Jian Zhu Chuanqi Gu Zhibin Sun Ruibin Xue Bin Zhou Shanghai Key Laboratory of atmospheric Particle Pollution and Prevention(LAP3) Department of Environmental Science and EngineeringFudan UniversityShanghai 200438China Institute of Eco-Chongming(IEC) Shanghai 202162China Institute of atmospheric sciences Fudan UniversityShanghai 200433China

Increased attentions to vehicle emission of NH_(3)have been paid since it is generally regarded as an important source in urban ***,we developed a movable instrument based on Differential Optical Absorption Spectroscopy(DOAS)principle for detecting on-road NH_(3),which can avoid the losses in the sampling process attributed to the non-sampling *** this mobile DOAS,the temporal resolution,detection limit and relative error for NH_(3)were 1 min,2.29 ppbv and 4.57%±2.44%,*** employed to the on-road measurements along the arterial highway in Shanghai,the spatial distributions of NH_(3)and NO were obtained,and their dependence of traffic and road conditions were *** slopes of linear regression between NH_(3)and NO were 0.40,0.02 and 0.07 on the Middle Ring Road,Outer Ring Road and Chongming Island Ring *** indicates that light gasoline vehicles(LGVs)were found to be the main contributor to NH_(3)emissions,while heavy-duty diesel vehicles(HDVs)mainly emitted *** on the measured NH_(3)in the tunnel,the mileagebased NH_(3)emission factor per vehicle was estimated to be 17.9±6.3 mg/*** reported open-path instrument can be broadly used in on-road pollutant monitoring or vehicle emissions,and the measurements can reveal the real situation of emission characteristics,even find the abnormal operations of vehicle catalyst system.

关键词： Ammonia Traffic emissions DOAS Emission factor Mobile measurements

Potential for soil carbon sequestration under conservation agriculture in a warming climate

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Science Bulletin 2024年第13期69卷 2030-2033页

作者： Lijun Yu Wen Zhang Jingjing Liu Wenjuan Sun Qing Zhang State Key Laboratory of atmospheric Boundary Layer Physics and atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of sciences Beijing 100049China Anyang Meteorological Service Anyang 455000China State Key Laboratory of Vegetation and environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China

Agricultural soil has numerous links with climate *** comprises a substantial part of farming systems that are affected by climate change and can significantly impact food security[1].An increase in the soil carbon(C)stock is associated with an increase in the crop ***,agricultural soil remains a source for all three major greenhouse gases(GHGs),i.e.,carbon dioxide(CO_(2)),methane and nitrous oxide,which contributes directly to climate *** addition,enhancing soil C sequestration in agricultural land could offset GHG emissions,promote more sustainable and climate-resilient agricultural systems.

关键词： soil warming agricultural

Drivers of East Asian summer monsoon variability:Global oceans and the Tibetan Plateau

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Science Bulletin 2024年第16期69卷 2487-2490页

作者： Anmin Duan Guoxiong Wu Bin Wang Andrew G.Turner Jun Hu Wenting Hu Ping Zhang Die Hu Yuheng Tang Center for Marine Meteorology and Climate Change State Key Laboratory of Marine Environmental ScienceCollege of Ocean and Earth SciencesXiamen UniversityXiamen 361102China State Key Laboratory of Numerical Modeling for atmospheric sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China department of atmospheric sciences School of Ocean and Earth Science and TechnologyUniversity of HawaiiHonolulu 96822USA department of Meteorology University of ReadingReading RG67BEUK

The East Asian summer monsoon(EASM)profoundly influences the hydroclimate,ecosystems,and water resources of a densely populated region in *** EASM can lead to floods,droughts,significant economic losses,and social disruption in East Asia and Southeast *** the Indian and African monsoons,the EASM is shaped by both tropical and extratropical climate systems,including tropical oceanic modes,cross-equatorial airflows,the Madden-Julian Oscillation,the thermal condition of the Tibetan Plateau,the South Asia High,and the mid-latitude westerly jet.

关键词： Tibetan monsoon East

Development and evaluation of an online monitoring single-particle optical particle counter with polarization detection

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Journal of environmental sciences 2024年第4期138卷 585-596页

作者： Weijie Yao Xiaole Pan Yu Tian Hang Liu Yuting Zhang Shandong Lei Junbo Zhang Yinzhou Zhang LinWu Yele Sun Zifa Wang State Key Laboratory of atmospheric Boundary Layer Physics and atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary sciences University of Chinese Academy of SciencesBeijing 100049China Center for Excellence in Regional atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

We developed a single-particle optical particle counter with polarization detection(SOPC)for the real-time measurement of the optical size and depolarization ratio(defined as the ratio of the vertical component to the parallel component of backward scattering)of atmospheric particles,the polarization ratio(DR)value can reflect the irregularity of the *** SOPC can detect aerosol particles with size larger than 500 nm and the maximum particle count rate reaches~1.8×10^(5)particles per *** SOPC uses a modulated polarization laser to measure the optical size of particles according to forward scattering signal and the DR value of the particles by backward S and P signal *** sampling rate of the SOPC was 106#/(sec·channel),and all the raw data were processed *** calibration curve was obtained by polystyrene latex spheres with sizes of 0.5-10μm,and the average relative deviation of measurement was 3.96% for sub 3μm particles.T-matrix method calculations showed that the DR value of backscatter light at 120°could describe the variations in the aspect ratio of particles in the above size *** performed insitu observations for the evaluation of the SOPC,the mass concentration constructed by the SOPC showed good agreement with the PM_(2.5)measurements in a nearby state-controlled monitoring *** instrument could provide useful data for source appointment and regulations against air pollution.

关键词： Instrument development Single particle detection Measurement uncertainty Optical simulation Mass concentration

Development of an automatic measurement system using atmospheric pressure photoionization ultrahigh-resolution mass spectrometry and application for on-line analysis of particulate matter

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Journal of environmental sciences 2024年第4期138卷 516-530页

作者： Yayuan Dong Ranran Liu Ling Xie Xiaole Pan Yele Sun Lin Wu ZifaWang State Key Laboratory of atmospheric Boundary Layer Physics and atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary sciences University of Chinese Academy of SciencesBeijing 100049China Center for Excellence in Regional atmospheric Environment Chinese Academy of SciencesInstitute of Urban EnvironmentXiamen 361021China

On-line chemical characterization of atmospheric particulate matter(PM)with soft ionization technique and ultrahigh-resolution Mass Spectrometry(UHRMS)provides molecular information of organic constituents in real *** we describe the development and application of an automatic measurement system that incorporates PM_(2.5)sampling,thermal desorption,atmospheric pressure photoionization,and UHRMS *** formulas of detected organic compounds were deducted from the accurate(±10 ppm)molecular weights obtained at a mass resolution of 100,000,allowing the identification of small organic compounds in PM_(2.5).Detection efficiencies of 28 standard compounds were determined and we found a high sensitivity and selectivity towards organic amines with limits of detection below 10 *** a proof of principle,PM_(2.5)samples collected off-line in winter in the urban area of Beijing were analyzed using the Ionization Module and HRMS of the *** automatic system was then applied to conduct on-line measurements during the summer time at a time resolution of 2 *** detected organic compounds comprised mainly CHON and CHN compounds below 350 m/*** seasonal variations in elemental composition were observed with shorter carbon backbones and higher O/C ratios in summer than that in *** result is consistent with stronger photochemical reactions and thus a higher oxidation state of organics in *** variation in signal intensity of each formula provides crucial information to reveal its source and formation *** summary,the automatic measurement system serves as an important tool for the on-line characterization and identification of organic species in PM_(2.5).

关键词： PM_(2.5) Chemical composition On-line measurement technique High resolution mass spectrometry