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Variations and drivers of aerosol vertical characterization after clean air policy in China based on 7-years consecutive observations

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Journal of Environmental Sciences 2023年第3期125卷 499-512页

作者： Xi Chen Ting Yang Haibo wang Futing wang zifa wang State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

Understanding the aerosol vertical characterization is of great importance to both climate and atmospheric environment. This study investigated the variations of aerosol profiles over eight regions of interest in China after clean air policy(2013-2019) and discussed the drivers of the vertical aerosol structure, using observations from active satellite measurements(CALIPSO). From the annual variation, the amplitude of extinction coefficient profiles showed a decreasing trend with fluctuations, and the maximum was 0.21 km-1in BeijingTianjin-Hebei(JJJ). For regions suffered from air pollution, the variation was greatest below 0.45 km, while it was between 1-1.5 km for Sichuan Basin. The correlation coefficient between the relative humidity(RH) and the extinction coefficient indicated that the increase of RH inhibited the decrease of the extinction coefficient in the Yangtze River Delta. In most regions, the main aerosol subtypes were polluted dust and polluted continental, but they were coarser in JJJ and North West. The frequency of concurrency of dust and polluted dust aerosols decreased in JJJ, but polluted continental aerosols occurred more frequently. Further, the aerosol extinction coefficient profiles under different pollution conditions showed that it changed most during heavy pollution periods in JJJ, especially in 2017, with a significant aerosol loading between700 and 1200 m. The atmospheric reanalysis data revealed that the weak convergence at low level and the divergence at high level supported the upward transport of aerosols in 2017. Overall, the differences in divergence allocation, RH, and wind filed were the main meteorological drivers.

关键词： Aerosol Vertical characteristic China CALIPSO Pollution period

Deep learning for P-wave arrival picking in earthquake early warning

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Earthquake Engineering and Engineering Vibration 2021年第2期20卷 391-402页

作者： wang Yanwei Li Xiaojun wang zifa Shi Jianping Bao Enhe College of Architecture and Civil Engineering Beijing University of TechnologyBeijing 100022China Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering Guilin University of TechnologyGuilin 541004China College of Architecture and Civil Engineering Henan UniversityKaifeng 475004China Institute of Engineering Mechanics China Earthquake AdministrationHarbin 150080China China Academy of Railway Sciences China Railway CorporationBeijing 100081China

Fast and accurate P-wave arrival picking significantly affects the performance of earthquake early warning(EEW)*** P-wave picking algorithms used in EEW have encountered problems of falsely picking up noise,missing P-waves and inaccurate P-wave arrival *** address these issues,an automatic algorithm based on the convolution neural network(DPick)was developed,and trained with a moderate number of data sets of 17,717 *** to the widely used approach of the short-term average/long-term average of signal characteristic function(STA/LTA),DPick is 1.6 times less likely to detect noise as a P-wave,and 76 times less likely to miss *** terms of estimating P-wave arrival time,when the detection task is completed within 1 s,DPick′s detection occurrence is 7.4 times that of STA/LTA in the 0.05 s error band,and 1.6 times when the error band is 0.10 *** verified that the proposed method has the potential for wide applications in EEW.

关键词： P-wave arrival convolution neural network deep learning earthquake early warning

Seasonal variation of the temperature profile and its characteristics within urban roughness sublayer

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Chinese Science Bulletin 2009年第3期54卷 468-473页

作者： wang XiQuan wang zifa GUO HU Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Beijing Meteorological Bureau Beijing 100089 China

By using conventional micro-meteorological observation data of Beijing Yuetan Park Tower (180 m), the temperature profile of urban boundary layer (UBL), its characteristics and seasonal variation are analyzed. The main results are as follows: (1) In winter, the interdiurnal surface air temperature varia- tion at the surface is not synchronized with that of the upper levels, other than in summer and other seasons, which illuminates the impacts of Beijing’s geographical location, sky view factor and stably stratified nocturnal inversion. (2) Except that the stratification is unstable around noon, the stratifica- tion in the roof layer or above-roof layer is of seasonal variability, which is weak unstable or weak sta- ble in winter or summer respectively. This weak stable stratification possibly inhibits urban pollutant dispersion upwards in summer season. (3) The effect of urban building rooftop on the UBL thermal state has seasonal difference, that is, the rooftop plays the role of heating or cooling the urban roughness sublayer, in summer or winter respectively, which is similar to the effects of the Qing- hai-Tibet Plateau on the atmospheric thermal state.

关键词：城市边界层温度季节变更北京

Effect of urbanization on the winter precipitation distribution in Beijing area

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Science China Earth Sciences 2009年第2期52卷 250-256页

作者： wang XiQuan wang zifa QI YanBin GUO Hu Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Jilin Province Weather Modification Offices Changchun 130062China Beijing Meteorological Bureau Beijing 100089China

According to the urbanization extent of Beijing area, and with 1980 as a turning point, the duration from 1961 to 2000 is divided into two periods: one is defined as the slow urbanization period from 1961 to 1980, and other one as the fast urbanization period from 1981 to 2000. Based on the 40-year’s precipi-tation data of 14 standard weather stations in Beijing area, the effect of urbanization on precipitation distribution is studied. It is found that there has been a noticeable and systematic change of winter precipitation distribution pattern between these two periods in Beijing area: in the slow urbanization period, the precipitation in the southern part of Beijing is more than that in the northern part; but in the fast urbanization period, the precipitation distribution pattern is reverse, i.e. the precipitation in the southern part is less than that in the northern part; But in other seasons, the precipitation distribution pattern did not change remarkably in general. The possible cause resulting in the change of winter precipitation distribution pattern, might be that with urban area extension, the effects of "urban heat island" and "urban dry island" become more and more intensified, and increase hydrometeors evapo-ration below precipitable cloud, and then cause less precipitation received on the ground surface in the downtown and the southern part. It is also noteworthy to further research why the precipitation distri-bution pattern does not change systematically in other seasons except winter after intense urbaniza-tion in Beijing area.

关键词： urbanization urban precipitation urban heat island urban dry island Beijing area

Observation of Wind Shear during Evening Transition and an Estimation of Submicron Aerosol Concentrations in Beijing Using a Doppler Wind Lidar

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Journal of Meteorological Research 2017年第2期31卷 350-362页

作者： Yong CHEN Junling AN Xiquan wang Yele SUN zifa wang Jing DUAN State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 Center for Excellence in Urban Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021 Chinese Academy of Meteorological Sciences Beijing 100081

The wind speed and direction measured over six months by a Doppler wind lidar（Windcube-8）were compared with wind cup anemometers mounted on the 325-m Beijing meteorological tower（BMT）.Five mountain–plain wind cases characterized by wind direction shear were selected based on the high-frequency（1.1 s）wind profile of the Windcube-8 and analyzed with 1-h mesoscale surface weather *** analyzed was the relationship between insitu PM_1（aerodynamic diameter≤1μm）concentrations measured at 260 m on BMT and the carrier-to-noise ratio（CNR）of the co-located *** results showed that the 10-min averaged wind speed and direction were highly correlated（R=0.96–0.99）at three matched levels（80,140,and 200 m）.The evening transition duration was1–3 h,with an average wind speed of 1 m s^（–1） at 80 m above the *** addition,there was a zero horizontalwind-speed zone along the wind direction shear line,and in one case,the wind speed was characterized by a Kelvin–Helmholtz gravity *** variability of the PM_1 concentrations was captured by the CNR of the Windcube-8 in a fair weather period without the long-range transport of dust.

关键词： mountain–plain wind wind shear wind lidar PM_1

Foreshowing of the Western Pacific tropical cyclone track to PM10 air pollution episode in the Beijing area

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Chinese Science Bulletin 2009年第5期54卷 830-835页

作者： wang XiQuan wang zifa YU Tong GONG YanBang Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Beijing Environmental Protection Monitoring Center Beijing 100084 China

By utilizing the air quality monitoring data and the NCEP reanalysis data, the relationship between thePM10 air pollution episode and synoptic situation is analyzed in the Beijing area. It is interesting to findthat PM10 air pollution episode in and around the Beijing area is correlated with the Western Pacifictropical cyclone track to some extent, namely when a tropical cyclone lands southward to the Chang-jiang River, PM10 air pollution episode is not easy to take place generally in the Beijing area; but when atropical cyclone moves northward and finally lands at the Korea Peninsula or the Japanese mainland,and under this condition the Beijing area is generally controlled by weak high or weak low for severaldays, PM10 air pollution episode often takes place in one day or several days. Above findings indicatethat predicting the Western Pacific tropical cyclone track can foretell whether or not PM10 air pollutionepisode takes place in the Beijing area, which can offer a technique for urban air quality prediction andair pollution source management in the Beijing area.

关键词： PM10 空气污染西太平洋热带飓风轨道北京空气质量

Simulating Dry Deposition Fluxes of PM_(10) and Particulate Inorganic Nitrogen over the Eastern China Seas During a Severe Asian Dust Event Using WRF-Chem Model

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Journal of Ocean University of China 2012年第3期11卷 301-314页

作者： YAN Han GAO Huiwang YAO Xiaohong wang zifa Key Laboratory of Marine Environment and Ecology Ministry of Education of ChinaOcean University of ChinaQingdao 266100P.R.China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029P.R.China

A WRF-Chem model including a comprehensive gas-phase nitrogen chemistry module was used to simulate a severe dust event appearing in the eastern China on 19-25 March, 2002. The modeling result well reproduced PM10 concentrations in various distances from the dust sources and the transport pathway of the dust strom. The results showed that both the concentrations and the dry deposition fluxes of PM10 increased over the China seas during the dust event following the passage of a cold front system. The maximum fluxes of PM10 in the Yellow Sea and the East China Sea during the dust event were 5.5 and 8.4 times of those before the event, respectively. However, the temporal variations of the dry deposition fluxes of particulate inorganic nitrogen differed over the Yellow Sea from those over the East China Sea. Nitrate and ammonium in the whole northern China rapidly decreased because of the intrusion of dust-loaded air on 19 March. The dust plume arrived in the Yellow Sea on 20 March, decreasing the particulate inorganic nitrogen in mass concentration accordingly. The minimum dry deposition fluxes of nitrate and ammonium in the Yellow Sea were about 3/5 and 1/6 of those before the dust arrival, respectively. In contrast, when the dust plume crossed over the Yangtze Delta area, it became abundant in nitrate and ammonium and increased the concentrations and dry deposition fluxes of particulate inorganic nitrogen over the East China Sea, where the maximum dry deposition fluxes of nitrate and ammonium increased approximately by 4.1 and 2.6 times of those prior to the dust arrival.

关键词： Asian dust aerosol inorganic particulate nitrogen dry deposition flux WRF-Chem model

A Rapid Estimation Method for Post-earthquake Building Losses

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International Journal of Disaster Risk Science 2023年第3期14卷 428-439页

作者： Dengke Zhao zifa wang Jianming wang Dongliang Wei Yang Zhou Zhaoyan Li Institute of Engineering Mechanics China Earthquake AdministrationHarbin 150080China CEAKJ ADPRHexa Inc. Shaoguan 512000China

Rapid estimation of post-earthquake building damage and loss is very important in urgent response *** current approach leaves much room for improvement in estimating ground motion and correctly incorporating the uncertainty and spatial correlation of the *** study proposed a new approach for rapidly estimating post-earthquake building loss with reasonable *** proposed method interpolates ground motion based on the observed ground motion using the Ground Motion Prediction Equation(GMPE)as the *** samples the building seismic loss quantile considering the spatial loss correlation that is expressed by Gaussian copula,and kriging is applied to reduce the dimension of direct sampling for estimation *** proposed approach was validated using three historical earthquake events in Japan with actual loss reports,and was then applied to predict the building loss amount for the March 2022 Fukushima Mw7.3 *** proposed method has high potential in future emergency efforts such as search,rescue,and evacuation planning.

关键词： Earthquake building loss estimation Fukushima earthquake 2022 Gaussian copula sampling Japan Spatial correlation of earthquake losses Spatial interpolation of ground motion

Vertical aerosol data assimilation technology and application based on satellite and ground lidar:A review and outlook

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Journal of Environmental Sciences 2023年第1期123卷 292-305页

作者： Ting Yang Hongyi Li Haibo wang Youwen Sun Xi Chen Futing wang Lei Xu zifa wang State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Key Laboratory of Environmental Optics and Technology Anhui Institute of Optics and Fine MechanicsHFIPSChinese Academy of SciencesHefei 230031China University of Chinese Academy of Sciences Beijing 100049China Department of Precision Machinery and Precision Instrumentation University of Science and Technology of ChinaHefei 230026China

Observations and numerical models are mainly used to investigate the spatiotemporal distribution and vertical structure characteristics of aerosols to understand aerosol pollution and its ***,the limitations of observations and the uncertainties of numerical models bias aerosol calculations and *** assimilation combines observations and numerical models to improve the accuracy of the initial,analytical fields of models and promote the development of atmospheric aerosol pollution *** studies have been conducted to integrate multi-source data,such as aerosol optical depth and aerosol extinction coefficient profile,into various chemical transport models using various data assimilation algorithms and have achieved good assimilation *** definition of data assimilation and the main algorithms will be briefly presented,and the progress of aerosol assimilation according to two types of aerosol data,namely,aerosol optical depth and extinction coefficient,will be *** application of vertical aerosol data assimilation,as well as the future trends and challenges of aerosol data assimilation,will be further analysed.

关键词： Atmospheric pollution Atmospheric environment Air quality modelling Aerosol assimilation