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Parameterization of Sheared Entrainment in a Well-developed CBL.PartⅡ: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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Improving the WRF/urban modeling system in China by developing a national urban dataset

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Geoscience Frontiers 2022年第4期13卷 75-88页

作者： Huidong Li Fenghui Yuan lidu shen Yage Liu Zhonghua Zheng Xu Zhou CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China Lamont-Doherty Earth Observatory of Columbia University PalisadesNY 10964United States National Tibetan Plateau Data Centre Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

Accurate modeling of urban climate is essential to predict potential environmental risks in cities.Urban datasets,such as urban land use and urban canopy parameters(UCPs),are key input data for urban climate models and largely affect their performance.However,access to reliable urban datasets is a challenge,especially in fast urbanizing countries.In this study,we developed a high-resolution national urban dataset in China(NUDC)for the WRF/urban modeling system and evaluated its effect on urban climate modeling.Specifically,an optimization method based on building morphology was proposed to classify urban land use types.The key UCPs,including building height and width,street width,surface imperviousness,and anthropogenic heat flux,were calculated for both single-layer Urban Canopy Model(UCM)and multiple-layer Building Energy Parameterization(BEP).The results show that the derived morphological-based urban land use classification could better reflect the urban characteristics,compared to the socioeconomic-function-based classification.The UCPs varied largely in spatial within and across the cities.The integration of the developed urban land use and UCPs datasets significantly improved the representation of urban canopy characteristics,contributing to a more accurate modeling of near-surface air temperature,humidity,and wind in urban areas.The UCM performed better in the modeling of air temperature and humidity,while the BEP performed better in the modeling of wind speed.The newly developed NUDC can advance the study of urban climate and improve the prediction of potential urban environmental risks in China.

关键词： Urban climate modeling UCM BEP Urban land use Urban canopy parameter Chinese cities

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Characteristics of Boundary Layer Structure during a Persistent Haze Event in the Central Liaoning City Cluster, Northeast China

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Journal of Meteorological Research 2018年第2期32卷 302-312页

作者： Xiaolan LI Yangfeng WANG lidu shen Hongsheng ZHANG Hujia ZHAO Yunhai ZHANG Yanjun MA Institute of Atmospheric Environment China Meteorological Administration Shenyang 110166 shenyang Regional Climatic Center Shenyang 110166 Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic Sciences School of Physics Peking University Beijing 100871

The characteristics of boundary layer structure during a persistent regional haze event over the central Liaoning city cluster of Northeast China from 16 to 21 December 2016 were investigated based on the measurements of particulate matter（PM） concentration and the meteorological data within the atmospheric boundary layer（ABL）. During the observational period, the maximum hourly mean PM_（2.5） and PM10 concentrations in shenyang, Anshan, Fushun, and Benxi ranged from 276 to 355 μg m–3 and from 378 to 442 μg m–3, respectively, and the lowest hourly mean atmospheric visibility（VIS） in different cities ranged from 0.14 to 0.64 km. The central Liaoning city cluster was located in the front of a slowly moving high pressure and was mainly controlled by southerly winds. Wind speed（WS） within the ABL（〈 2 km） decreased significantly and WS at 10-m height mostly remained below 2 m s–1 during the hazy episodes, which was favorable for the accumulation of air pollutants. A potential temperature inversion layer existed throughout the entire ABL during the earlier hazy episode [from 0500 Local Time（LT） 18 December to 1100 LT 19 December], and then a potential temperature inversion layer developed with the bottom gradually decreased from 900 m to 300 m. Such a stable atmospheric stratification further weakened pollutant dispersion. The atmospheric boundary layer height（ABLH） estimated based on potential temperature profiles was mostly lower than 400 m and varied oppositely with PM_（2.5） in shenyang. In summary, weak winds due to calm synoptic conditions, strong thermal inversion layer, and shallow atmospheric boundary layer contributed to the formation and development of this haze event.The backward trajectory analysis revealed the sources of air masses and explained the different characteristics of the haze episodes in the four cities.

关键词： haze event thermal inversion layer atmospheric boundary layer Northeast China

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Spatiotemporal Variations and Regional Transport of Air Pollutants in Two Urban Agglomerations in Northeast China Plain

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Chinese Geographical Science 2019年第6期29卷 917-933页

作者： LI Xiaolan HU Xiaoming SHI Shuaiyi shen lidu LUAN Lan MA Yanjun Institute of Atmospheric Environment China Meteorological AdministrationShenyang 110166China Center for Analysis and Prediction of Storms University of OklahomaNormanOK 73072USA School of Meteorology University of OklahomaNormanOK 73072USA State Key Laboratory of Remote Sensing Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China shenyang Regional Climatic Center Shenyang 110166China Chinese Academy of Meteorological Sciences Beijing 100081China

Characteristics of air pollution in Northeast China(NEC) received less research attention in the past comparing to other heavily polluted regions in China.Spatiotemporal variations of six criteria air pollutants(PM10, PM2.5, SO2, NO2, O3 and CO) in Central Liaoning Urban Agglomeration(CLUA) and Harbin-Changchun Urban Agglomeration(HCUA) in NEC Plain were analyzed in this study based on three-year hourly observations of air pollutants and meteorological variables from 2015 to 2017.The results indicated that the annual mean concentrations of air pollutants are generally higher in the middle and southern regions in NEC Plain and lower in the northern region.Megacities such as shenyang, Harbin and Changchun experience severe air pollution, with a three-year averaged air quality index(AQI) larger than 80, far exceeding the daily AQI standard at the first-level of 50 in China.The annual mean PM and SO2 concentrations decrease most significantly in NEC urban agglomerations from 2015 to 2017, followed by CO and NO2, while O3 shows a slight increasing trend.All the six pollutants exhibit obvious seasonal and diurnal variations, and these variations are dictated by local emission and meteorological conditions.PM2.5 and O3 concentrations in NEC urban agglomerations strongly depend on wind conditions.High O3 concentrations at different cities usually occur in presence of strong winds but are independent on wind direction(WD), while high PM2.5 is usually accompanied by weak winds and poor dispersion condition, and sometimes also occur when the northerly or southerly winds are strong.Regional transport of air pollutants between NEC urban agglomerations is common.A severe haze event on November 1–4, 2017 is examined to demonstrate the role of regional transport on pollution.

关键词： criteria air pollutant meteorological condition regional transport urban agglomeration of Northeast China

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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：沈历都孙鉴泞袁仁民刘鹏 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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2019年辽宁开原龙卷风观测事实分析

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灾害学 2021年第1期36卷 112-116页

作者：阎琦张爱忠沈历都崔锦赵梓淇辽宁省气象台辽宁沈阳110166 民航东北地区空中交通管理局气象中心辽宁沈阳110169 沈阳区域气候中心辽宁沈阳110166 中国气象局沈阳大气环境研究所辽宁沈阳110166

利用加密自动站、FY-4A卫星及多普勒雷达等观测资料,对2019年7月3日辽宁开原突发龙卷天气进行分析。结果表明:在冷涡减弱阶段,中纬度冷空气活动频繁,冷涡底部500 hPa与850 hPa的短波槽垂直分布,利于辽宁北部对流不稳定加强。FY-4A可见... 详细信息

利用加密自动站、FY-4A卫星及多普勒雷达等观测资料,对2019年7月3日辽宁开原突发龙卷天气进行分析。结果表明:在冷涡减弱阶段,中纬度冷空气活动频繁,冷涡底部500 hPa与850 hPa的短波槽垂直分布,利于辽宁北部对流不稳定加强。FY-4A可见光云图显示,开原龙卷生消迅速,有明显的上冲云顶。雷达反射率因子特征是,对流单体合并形成超级单体,出现连续体扫的中气旋、并伴有钩状回波,三维显示出现空洞结构;强回波区向移动方向一侧倾斜、垂直剖面存在穹隆结构和有界弱回波区时,钩状回波处最容易产生龙卷;空洞的位置与中气旋和钩状回波中心区相吻合,表明超级单体在此处产生强烈涡旋,有利于漏斗云脱离母体向地面发展。速度产品上出现对称的正负速度区,旋转速度持续增大,且正负速度区不断向下发展,低仰角探测到紧邻的速度对时,中气旋相应也出现向下延伸和迅速收缩,预示龙卷的发生。东北冷涡以及蒙古气旋前侧低压带、低层干冷空气侵入导致锋生等动力条件,是辽宁北部对流的天气尺度和中α尺度的触发机制。

关键词：冷涡突发龙卷中尺度特征触发机制辽宁开原

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系留气艇探测风速的误差订正及其应用评估

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气象科学 2013年第5期33卷 485-491页

作者：王昊哲孙鉴泞朱莲芳刘鹏沈历都南京大学大气科学学院南京210093 苏州市气象局江苏苏州215131

使用系留气艇探空系统在常州、苏州、南京市区对边界层风速、温度、湿度廓线进行了观测,原始数据表明探测结果存在明显的系统误差。本文主要讨论风速订正问题,分析发现风速误差与高度和风速有关,据此提出了依据高度和依据风速的两种订... 详细信息

使用系留气艇探空系统在常州、苏州、南京市区对边界层风速、温度、湿度廓线进行了观测,原始数据表明探测结果存在明显的系统误差。本文主要讨论风速订正问题,分析发现风速误差与高度和风速有关,据此提出了依据高度和依据风速的两种订正方案。对比结果表明:两种方案都能有效修正系留气艇测量风速的系统误差,高度订正方案表现更好。本文还用订正后的系留气艇探测结果与苏州市气象局的风廓线雷达资料进行对比,结果显示风廓线雷达探测结果在500 m以下系统偏小。

关键词：系留气艇大气边界层探空资料风廓线雷达误差订正

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城市化对辽宁省近地面风速的影响分析

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气象 2020年第9期46卷 1153-1164页

作者：敖雪翟晴飞崔妍沈历都周晓宇赵春雨朱玲沈阳区域气候中心沈阳110166 辽宁省人工影响天气办公室沈阳110166

利用1979-2018年辽宁省逐月风速资料和再分析资料,结合卫星遥感分类方法,并采用UMR(urban minus rural)方法和OMR(observation minus reanalysis)方法定量分析了城市化对辽宁省近地面风速的影响。研究表明:近40年辽宁省年和四季风速均... 详细信息

利用1979-2018年辽宁省逐月风速资料和再分析资料,结合卫星遥感分类方法,并采用UMR(urban minus rural)方法和OMR(observation minus reanalysis)方法定量分析了城市化对辽宁省近地面风速的影响。研究表明:近40年辽宁省年和四季风速均呈减小趋势,城市站的减小速率明显快于乡村站,UMR值的变化趋势为-0.11 m·s^-1·(10 a)^-1,城市化影响贡献率为73.3%;空间分布上,辽宁中北部城市群减小趋势较明显,南部和东南部风速减小相对缓慢;UMR方法计算的城市化影响呈现自西向东逐渐增强的纬向分布形势。再分析资料的减小趋势与乡村站的减小趋势较接近,春季风速的减小速率最明显;OMR值的变化趋势为-0.10 m·s^-1·(10 a)^-1,对应的城市化影响贡献率为66.7%,利用两种方法计算得到的城市化影响和贡献率较一致,均能在一定程度上反映城市化对风速的影响。空间分布上,再分析资料显示渤海海峡风速呈微弱增加趋势,风速减小的高值区位于渤海北部和黄海北部。两种方法计算的城市化影响空间分布均呈现为西部和南部受城市化影响较小、中东部受城市化影响较大,一致性较好。

关键词：城市化风速气候变化辽宁省

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基于EOF分解的辽宁省城市化气候效应检测

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地理科学进展 2020年第9期39卷 1532-1543页

作者：敖雪翟晴飞崔妍周晓宇沈历都赵春雨宁喜龙沈阳区域气候中心沈阳110166 辽宁省人工影响天气办公室沈阳110166 阜新市气象局辽宁阜新123100

论文利用1961—2017年逐日气象数据以及社会经济数据,构建新的城市化指标,分析了城市化对辽宁气候变化的影响。研究表明:辽宁省气温呈显著增加趋势,国家站增温速率明显快于乡村站;城市化对平均最低气温影响最显著,平均气温次之,平均最... 详细信息

论文利用1961—2017年逐日气象数据以及社会经济数据,构建新的城市化指标,分析了城市化对辽宁气候变化的影响。研究表明:辽宁省气温呈显著增加趋势,国家站增温速率明显快于乡村站;城市化对平均最低气温影响最显著,平均气温次之,平均最高气温相对较弱;就四季而言,秋季城市化影响贡献率最大,冬季和夏季次之,春季相对较小。空间分布上,城市化影响高值区位于辽宁中部和西部地区,与辽宁省城市化发展水平基本吻合,城市化对气温的影响不是单一的,对于多数地区尤其是沈阳、大连等经济发展水平较高的地区,起到增温作用,但也对少数台站的升温起到了抑制作用。气温指标中,城市化对年和四季平均气温的影响最显著,对应模态均是第一模态,方差贡献率均在89%以上,空间相关性均通过显著性检验,其次是平均最低气温和日较差;季节变化特征上,冬季和春季的增温相对于秋季和夏季明显。降水指标基本对应第二模态,方差贡献率在9%~18%之间,城市化对气温的影响强于降水;结合时间系数,城市化效应表现为春季和冬季降水、大雨和暴雨日数略有增加,年、夏季、秋季降水、小雨、中雨日数减少。城市化对降水的影响表现出两面性,一方面使年降水和小量级降水减少,另一方面又使极端降水事件增多。

关键词：城市化 EOF 气候变化辽宁省

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2021年3月27-28日中国北方沙尘天气特征分析

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气象与环境学报 2023年第4期39卷 9-16页

作者：徐红陈军庆路海军宋明坤陈玺伍龚强朱玲沈历都沈阳区域气候中心辽宁沈阳110166 93161部队辽宁沈阳110015 中国科学院沈阳应用生态研究所辽宁沈阳110016

选用常规气象观测资料、探空站气象观测资料、卫星云图反演沙尘产品、NCEP/NCAR再分析资料对2021年3月27—28日中国北方一次典型强沙尘天气进行分析。结果表明:干燥(平均降水量小于10 mm、降水量负距平的地区超过80%)、高热(气温较常年... 详细信息

选用常规气象观测资料、探空站气象观测资料、卫星云图反演沙尘产品、NCEP/NCAR再分析资料对2021年3月27—28日中国北方一次典型强沙尘天气进行分析。结果表明:干燥(平均降水量小于10 mm、降水量负距平的地区超过80%)、高热(气温较常年偏高超过6℃)为此次沙尘天气的气候条件。同时,受蒙古气旋影响,中低空、地面大风和强烈的垂直上升运动为此次沙尘天气提供了动力条件。大气温度直减率、抬升指数、K指数、对流有效位能指数、I_(Conve(700—850))指数、I_(Conve(700—sfc))指数、PW指数表明,沙源地大气层结存在不稳定状态,为沙尘天气发生提供了热力条件。24 h后向轨迹模型表明,沈阳上空500 m高度的沙尘来自内蒙古地表抬升至1000 m高空后远距离输送,而1000~2500 m高度的沙尘源自蒙古国4000~5000 m高空,随气流下沉远距离输送至目标区域。

关键词：大风动力条件热力条件后向轨迹模型

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