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Observational study of land-atmosphere turbulent flux exchange over complex underlying surfaces in urban and suburban areas

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Science China Earth Sciences 2021年第7期64卷 1050-1064页

作者： Jie SHA Jun ZOU jianning sun School of Atmospheric Sciences Nanjing UniversityNanjing 210023China Joint International Research Laboratory of Atmospheric and Earth System Sciences Nanjing UniversityNanjing 210023China Jiangsu Provincial Collaborative Innovation Center of Climate Change Nanjing 210023China

Based on observation data from urban observation stations in Nanjing and Suzhou at two heights in the roughness sublayer above the canopy and observation data at three heights in the SORPES station at the Xianlin Campus of Nanjing University in a suburban area,the of land-atmosphere turbulent flux exchange and the energy balance over complex underlying surfaces were *** results indicated that in the roughness sublayer above the canopy,the nearsurface momentum flux,sensible heat flux,and latent heat flux increase with height,and the observation value of the surface albedo increases with ***,the observation value of the net radiation decreases with height,thus resulting in a change in the urban surface energy budget with *** the SORPES station in the Xianlin Campus of Nanjing University located in a hilly area,the momentum flux,sensible heat flux,and latent heat flux of the ground observation field significantly differed from those of the two heights on the tower,while the two heights on the tower were extremely *** results indicate that the flux observation over the complex underlying surface exhibits adequate local only when it is conducted at a higher altitude above the *** turbulent flux observation results at a lower altitude in urban areas are underestimated,while the turbulent flux observation results near the surface produce a large deviation over the underlying hilly complex.

关键词： Complex underlying surface Land-atmosphere exchange Turbulent flux Observation height Local representativeness

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Parameterization of Sheared Entrainment in a Well-developed ***Ⅱ:A Simple Model for Predicting the Growth Rate of the CBL

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Advances in Atmospheric Sciences 2016年第10期33卷 1185-1198页

作者： Peng LIU jianning sun Lidu SHEN School of Atmospheric Sciences&Institute for Climate and Global ChangeNanjing UniversityNanjing 210023China Jiangsu Provincial Collaborative Innovation Center of Climate Change Nanjing 210023China

Following the parameterization of sheared entrainment obtained in the companion paper, Liu et al. （2016）, the present study aims to further investigate the characteristics of entrainment, and develop a simple model for predicting the growth rate of a well-developed and sheared CBL. The relative stratification, defined as the ratio of the stratification in the free atmosphere to that in the entrainment zone, is found to be a function of entrainment flux ratio （Ae）. This leads to a simple expression of the entrainment rate, in which Ae needs to be parameterized. According to the results in Liu et al. （2016）, Ae can be simply expressed as the ratio of the convective velocity scale in the sheared CBL to that in the shear-free CBL. The parameterization of the convective velocity scale in the sheared CBL is obtained by analytically solving the bulk model with several assumptions and approximations. Results indicate that the entrainment process is influenced by the dynamic effect, the interaction between mean shear and environmental stratification, and one other term that includes the Coriolis effect. These three parameterizations constitute a simple model for predicting the growth rate of a well-developed and sheared CBL. This model is validated by outputs of LESs, and the results show that it performs satisfactorily. Compared with bulk models, this model does not need to solve a set of equations for the CBL. It is more convenient to apply in numerical models.

关键词： sheared convective boundary layer relative stratification parameter entrainment rate entrainment flux ratio,convective velocity scale

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Characteristics of Secondary Circulations in the Convective Boundary Layer over Two-Dimensional Heterogeneous Surfaces

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Journal of Meteorological Research 2016年第6期30卷 944-960页

作者： SHEN Lidu sun jianning and LIU Peng School of Atmospheric Sciences & Institute for Climate and Global Change Nanjing University Jiangsu Provincial Collaborative Innovation Centre of Climate Change School of Earth and Space Sciences University of Science and Technology of China

Large-eddy simulations are conducted to investigate the impacts of the scale of chessboard-like heteroge- neous surface heating and the background wind on secondary circulations （SCs） in the convective boundary layer （CBL）. When the wind blows along the diagonal of the chessboard pattern, the cases with different heterogeneity length scales （λ = 1.2, 2.4, and 4.8 km） and weak background wind （U = 2.5 m s-1） suggest that there exists a threshold for the roll-like SCs, which is satisfied when the heterogeneity length scale is 1.6 times the boundary layer height （λ = 1.6zi）. During the CBL development, the SC intensity increases before this threshold is met, whereas it decreases thereafter. The cases with different background wind speeds （U = 2.5, 5.0, and 10.0 m s-1） and relatively large heterogeneity length scale （λ = 4.8 km） show that the SCs are strengthened by larger wind speeds when the heterogeneity length scale is so large that the threshold cannot be met during the CBL development. Another case with wind direction along neither the diagonal nor the side of the chessboard pattern shows that the roll-like SCs can still be triggered, but the roll axes are orientated along the diagonal of the chessboard pattern rather than along the wind direction.

关键词： background wind convective boundary layer heterogeneous surface large-eddy simulation secondary circulation turbulence

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Numerical Simulation of the Impact of Urban Non-uniformity on Precipitation

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Advances in Atmospheric Sciences 2016年第6期33卷 783-793页

作者： Yuqiang SONG Hongnian LIU Xueyuan WANG Ning ZHANG jianning sun School of Atmospheric Sciences Nanjing UniversityNanjing 210093 Dalian Meteorological Station Dalian 116000

To evaluate the influence of urban non-uniformity on precipitation, the area of a city was divided into three categories （commercial, high-density residential, and low-density residential） according to the building density data from Landsat satel- lites. Numerical simulations of three corresponding scenarios （urban non-uniformity, urban uniformity, and non-urban） were performed in Nanjing using the WRF model. The results demonstrate that the existence of the city results in more precip- itation, and that urban heterogeneity enhances this phenomenon. For the urban non-uniformity, uniformity, and non-urban experiments, the mean cumulative summer precipitation was 423.09 mm, 407.40 mm, and 389.67 mm, respectively. Urban non-uniformity has a significant effect on the amount of heavy rainfall in summer. The cumulative precipitation from heavy rain in the summer for the three numerical experiments was 278.2 mm, 250.6 mm, and 236.5 mm, respectively. In the non- uniformity experiments, the amount of precipitation between 1500 and 2200 （LST） increased significantly. Furthermore, the adoption of urban non-uniformity into the WRF model could improve the numerical simulation of summer rain and its daily variation.

关键词： urban non-uniformity urban precipitation WRF model

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Observation-based Estimation of Aerosol-induced Reduction of Planetary Boundary Layer Height

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Advances in Atmospheric Sciences 2017年第9期34卷 1057-1068页

作者： Jun ZOU jianning sun Aijun DING Minghuai WANG Weidong GUO Congbin FU School of Atmospheric Sciences and Institute for Climate and Global Change Nanjing University Joint International Research Laboratory of Atmospheric and Earth System Sciences of Ministry of Education Nanjing University

Radiative aerosols are known to influence the surface energy budget and hence the evolution of the planetary boundary layer. In this study, we develop a method to estimate the aerosol-induced reduction in the planetary boundary layer height （PBLH） based on two years of ground-based measurements at a site, the Station for Observing Regional Processes of the Earth System （SORPES）, at Nanjing University, China, and radiosonde data from the meteorological station of Nanjing. The observations show that increased aerosol loads lead to a mean decrease of 67.1 W m-2 for downward shortwave radiation （DSR） and a mean increase of 19.2 W m-2 for downward longwave radiation （DLR）, as well as a mean decrease of 9.6 W m-2 for the surface sensible heat flux （SHF） in the daytime. The relative variations of DSR, DLR and SHF are shown as a function of the increment of column mass concentration of particulate matter （PM2.5）. High aerosol loading can significantly increase the atmospheric stability in the planetary boundary layer during both daytime and nighttime. Based on the statistical relationship between SHF and PM2.5 column mass concentrations, the SHF under clean atmospheric conditions （same as the background days） is derived. In this case, the derived SHF, together with observed SHF, are then used to estimate changes in the PBLH related to aerosols. Our results suggest that the PBLH decreases more rapidly with increasing aerosol loading at high aerosol loading. When the daytime mean column mass concentration of PM2.5 reaches 200 mg m-2, the decrease in the PBLH at 1600 LST （local standard time） is about 450 m.

关键词： aerosol radiation atmospheric stability surface sensible heat flux planetary boundary layer height

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A comparative study of the land-atmosphere energy and water exchanges over the Tibetan Plateau and the Yangtze River Region

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Atmospheric and Oceanic Science Letters 2024年第2期17卷 52-59页

作者： Nan Yao Yaoming Ma Binbin Wang Jun Zou jianning sun Zhipeng Xie Land–Atmosphere Interaction and Its Climatic Effects Group State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijingChina College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijingChina College of Atmospheric Science Lanzhou UniversityLanzhouChina National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes DingriChina Kathmandu Center of Research and Education Chinese Academy of SciencesBeijingChina China–Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabadPakistan School of Atmospheric Sciences Nanjing UniversityNanjingChina Jiangsu Provincial Collaborative Innovation Center for Climate Change NanjingChina

正确认识不同区域能量和水分循环特征是研究局地地气相互作用及准确预测区域天气,气候变化的关键.为了研究属于干旱/半干旱气候的青藏高原(TP)和湿润/半湿润气候的长江流域(YRR)之间地表能量和水分交换的异同,本文对比分析了两个区域8... 详细信息

正确认识不同区域能量和水分循环特征是研究局地地气相互作用及准确预测区域天气,气候变化的关键.为了研究属于干旱/半干旱气候的青藏高原(TP)和湿润/半湿润气候的长江流域(YRR)之间地表能量和水分交换的异同,本文对比分析了两个区域8个不同地表类型(包括高山荒漠,高山草地,(平原)城市和(平原)草地等)观测站点的地表辐射和能量通量数据.结果显示:(1)TP由于高原大气层稀薄且空气洁净,年平均入射短波辐射为251.3W m^(-2),是YRR的1.7倍.加之高原地表反照率高导致反射辐射(59.6 W m^(-2))是YRR的2.87倍.入射及出射的长波辐射为231.5和338.0 W m^(-2),分别为YRR的0.64和0.83.而两个区域的净辐射差异不大;(2)草地站更多的潜热释放使得地表总加热效率高于城市和高山荒漠,TP和YRR的草地站的年平均潜热分别为35.0和38.8 W m^(-2),而植被稀疏且土壤干燥的高山荒漠地区感热最大,年平均感热为42.1 W m^(-2);其次是城市下垫面,其年平均感热为37.7 W m^(-2).研究结果揭示了不同气候背景下典型下垫面地气相互作用特征,为地气相互作用过程深入分析奠定了基础.

关键词：能量和水分交换辐射分量地表能量通量青藏高原长江流域不同地表类型

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Long-term observation of air pollution-weather/climate interactions at the SORPES station： a review and outlook

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Frontiers of Environmental Science & Engineering 2016年第5期10卷 9-23页

作者： Aijun Ding Wei Nie Xin Huang Xuguang Chi jianning sun Veli-Matti Kerminen Zheng Xu Weidong Guo Tuukka Petaja Xiuqun Yang Markku Kulmala Congbin Fu Joint International Research Laboratory of Atmospheric and Earth System Sciences (JirLATEST) Nanjing University Nanjing 210023 China Institute for Climate and Global Change Research School of Atmospheric Sciences Nanjing University Nanjing 210023 China Collaborative Innovation Center of Climate Change Jiangsu Province Nanjing 210023 China Department of Physics University of Helsinki Helsinki 00014 Finland

This work presents an overall introduction to the Station for Observing Regional Processes of the EarthSystem - SORPES in Nanjing, East China, and gives an overview about main scientific findings instudies of air pollution-weather/climate interactions obtained since 2011. The main results summarizedin this paper include overall characteristics of trace gases and aerosols, chemical transformationmechanisms for secondary pollutants like O3, HONO andsecondary ingrganic aerosols, and the airpollution- weather/climate interactions and feedbacks in mixed air pollution plumes from sources likefossil fuel combustion, biomass burning and dust storms. The future outlook of the development plan on instrumentation, networking and data-sharing for the SORPES station is also discussed.

关键词： Secondary pollution Ground-based measurement Planetary boundary layer meteorology Earth system processes

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Study on the influence of the discharge voltage on the ignition process of Hall thrusters

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Plasma Science and Technology 2020年第9期22卷 25-37页

作者： Wenbo LI Liqiu WEI Hong LI Yongjie DING jianning sun Haikuo CAI Daren YU Shangmin WANG Ning GUO School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001People's Republic of China Key Laboratory of Aerospace Plasma Propulsion Ministry of Industry and Information TechnologyHarbin 150001People's Republic of China Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of PhysicsLanzhou 730000People's Republic of China

A high-speed charge-coupled device camera was used to capture images of the plume and acceleration channel of a Hall effect thruster during ignition at different discharge *** better understand the influence of changes in the discharge voltage on the plasma parameters during thruster ignition,a particle-in-cell numerical model was used to calculate the distribution characteristics of the ion density and electric potential at different ignition moments under different discharge *** results show that when the discharge voltage is high,the ion densities in the plume and acceleration channel are significantly higher at the initial phase of thruster ignition;with the gradual strengthening of the ignition process,the propellant avalanche ionization during thruster ignition occurs earlier and the pulse current peak *** main reason for these phenomena is that the change in the discharge voltage results in different energy acquisitions of the emitted electrons entering the thruster channel.

关键词： Hall effect thruster ignition process discharge voltage PIC simulation CCD image

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对流边界层顶部光学湍流的室内模拟研究

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光学学报 2006年第9期26卷 1287-1292页

作者：袁仁民罗涛孙鉴泞中国科学技术大学地球和空间科学学院合肥230026 南京大学大气科学系南京210093

对流边界层顶部夹卷层是边界层和自由大气之间的过渡带，夹卷层的湍流结构是其主要特征之一。由于夹卷层的位置较高，进行精细结构观测很难，对此认识较少。利用尺寸为150cm×150cm×60cm室内对流水槽模拟了大气对流边界层的发生和发展... 详细信息

对流边界层顶部夹卷层是边界层和自由大气之间的过渡带，夹卷层的湍流结构是其主要特征之一。由于夹卷层的位置较高，进行精细结构观测很难，对此认识较少。利用尺寸为150cm×150cm×60cm室内对流水槽模拟了大气对流边界层的发生和发展。将准直光通过模拟对流边界层，根据光在湍流介质中的传输理论得到混合层顶部夹卷层的温度结构常数的特点，在夹卷层内，归一化的温度结构常数满足相同的规律；在高度0．8zi处，温度结构常数最小，随着高度增加，温度结构常数增大，置处达最大，然后又随着高度减逐渐小，在高度1．2zi处湍流消失。在边界层顶部zi处，归一化的温度结构常数处于一定的变化范围，归一化温度结构常数处于0．08～0．3之间，这可能与夹卷层的大尺度结构有关。

关键词：大气光学光学湍流温度结构常数夹卷层闪烁大尺度结构

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3,4-Oxo-isopropylidene-shikimic acid promotes adiopkine expression during murine 3T3-L1 fibroblast differentiation into adipocytes

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Journal of Traditional Chinese Medical Sciences 2014年第2期1卷 120-125页

作者： Shifen Dong Naomi Yasui Hiroko Negishi Ming Gao Yukio Yamori Katsumi Ikeda jianning sun Department of Pharmacology School of Chinese Materia MedicaBeijing University of Chinese MedicineBeijing 100029China School of Pharmacy and Pharmaceutical Sciences Mukogawa Women’s University11-68Nishinomiya 663-8179Japan Institute for World Health Development Mukogawa Women’s University11-68Nishinomiya 663-8179Japan

Objective:3,4-Oxo-isopropylidene-shikimic acid(ISA),a derivative of shikimic acid,has exhibited ameliorative effect on cognitive impairment in experimental animal models of *** study investigated the effect of ISA on lipid accumulation and adipokine secretion during differentiation of 3T3-L1 fibroblasts to ***:3T3-L1 cells were cultured and treated with ISA(50e800 mM)from days *** accumulation and triglyceride content were *** expression of adipokines(adiponectin,leptin,and resistin),CCAAT/enhancer binding protein(C/EBP)b,C/EBP a and peroxisome proliferator-activated receptor g(PPAR g)and PPAR target genes,including adipocyte fatty acid binding protein(aP2)and fatty acid synthase(FAS)were ***:ISA promoted 3T3-L1 fibroblast differentiation to adipocytes and increased triglyceride content by 26%.On mechanistic levels,ISA increased expressions of C/EBP b,PPAR g,C/EBP a,aP2 and ***,ISA stimulated expressions of adipokines secreted by adipocytes,including adiponectin,leptin,and ***:These findings demonstrated that ISA promoted adipogenesis by up-regulating expressions of C/EBP b,PPAR g,C/EBP a,aP2 and FAS,and also stimulated adipokines during adipocyte *** study should clarify the relationship between stimulation of adipokines and cognitive enhancing effect of ISA.

关键词： 3,4-Oxoisopropylideneshikimic acid 3T3-L1 fibroblasts Adipocytes Adipogenesis Adipokines

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