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performance of LIDAR- and radar-based turbulence intensity measurement in comparison with anemometer-based turbulence intensity estimation based on aircraft data for a typical case of terrain-induced turbulence in association with a typhoon

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Journal of Zhejiang University-Science A(Applied physics & Engineering) 2013年第7期14卷 469-481页

作者： p.w.chan Y.F.LEE Hong Kong Observatory

The Hong Kong Observatory (HKO) provides low-level turbulence alerting service for the Hong Kong International Airport (HKIA) through the windshear and turbulence warning system (wTwS). In the wTwS, turbulence intensities along the flight paths of the airport are estimated based upon correlation equations established between the surface anemometer data and the turbulence data from research aircraft before the opening of the airport. The research aircraft data are not available on day-to-day basis. The remote sensing meteorological instruments, such as the Doppler light detection and ranging (LIDAR) and radar, may be used to provide direct measurements of turbulence intensities over the runway corridors. The performances of LIDAR- and radar-based turbulence intensity data are studied in this paper based on actual turbulence intensity measurements made on 423 commercial jets for a typical case of terrain-induced turbulence in association with a typhoon. It turns out that, with the tuning of the relative operating characteristic (ROC) curve between hit rate and false alarm rate, the LIDAR-based turbulence intensity measurement performs better than the anemometer-based estimation of wTwS for turbulence intensity at moderate level or above. On the other hand, the radar-based measurement does not perform as well when compared with wTwS. By combining LIDAR- and radar-based measurements, the performance is slightly better than wTwS, mainly as a result of contribution from LIDAR-based measurement. As a result, the LIDAR-based turbulence intensity measurement could be used to replace anemometer-based estimate for non-rainy weather conditions. Further enhancements of radar-based turbulence intensity measurement in rain would be necessary.

关键词： Fault tolerant High availability quadruple vital computer (HAQVC) Reliability availability maintainability and safety (RAMS)

Multiscale simulation of the urban wind environment under typhoon weather conditions

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Building Simulation 2023年第9期16卷 1713-1734页

作者： Zihan Zhao Yiqing Xiao Chao Li p.w.chan Gang Hu Qingfeng Zhou School of Construction Engineering Shenzhen PolytechnicShenzhenChina School of Civil and Environmental Engineering Harbin Institute of Technology ShenzhenShenzhenChina Hong Kong Observatory KowloonHong KongChina Shenzhen Urban planning&Land Resources Research Center ShenzhenGuangdong 518055China

Accurate simulations of planetary boundary layer(pBL)winds in urban areas require combining meteorological knowledge and fine-grained geometrical *** fluid dynamics(CFD)is widely used to assess pedestrian wind comfort and wind disasters in planning resilient ***,the CFD-predicted pBL is highly affected by the inflow *** profiles under extreme weather conditions,such as tropical cyclones,can hardly be determined,and associated uniform logarithmic or power law expressions have not been *** this study,urban wind flow over mountainous terrain was simulated using a one-way nested simulation approach between mesoscale and microscale *** inflow wind speed,turbulence scalars,and potential temperature in the CFD code are sustained by the numerical weather prediction(Nwp)*** considering typhoon weather conditions were examined to improve the numerical accuracy in determining mesoscale typhoon structures and pedestrian-level wind *** numerical errors were quantified in mesoscale and microscale formulations.A new tendency assimilation was proposed by incorporating local-scale observations into the CFD *** approach entailed empirical mode decomposition to quantify the mean wind speed differences between the observations and Nwp results,which were then extrapolated to Nwp-CFD nested interfaces via multiplication by the spatial correlation *** numerical performance was validated against both on-site observations for meteorological purposes and wind profiles retrieved from the experimental LiDAR of the landfalling typhoon *** simulated wind field exhibited an increased accuracy in the local urban *** specifically,the index of agreement in wind speeds was improved from 0.28 to 0.72,and the mean absolute errors were reduced from 5.46 m/s to 1.89 m/s.

关键词： Nwp-CFD urban wind flow data assimilation typhoon disaster resilient cities

Computational fluid dynamics simulation of the wind flow over an airport terminal building

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Journal of Zhejiang University-Science A(Applied physics & Engineering) 2010年第6期11卷 389-401页

作者： Chun-ho LIU Dennis Y.C.LEUNG Alex C.S.MAN p.w.chan Department of Mechanical Engineering The University of Hong Kong Hong Kong Observatory

Turbulence in the wake generated by wind flow over buildings or obstacles may produce complex flow patterns in downstream *** include the recirculating flow and wind deficit areas behind an airport terminal building and their potential impacts on the aircraft landing on nearby runways.A computational fluid dynamics(CFD) simulation of the wind flow over an airport terminal building was performed in this study of the effect of the building wake on landing *** normal meteorological conditions,the studied airport terminal building causes limited effects on landing aircraft because most of the aircraft have already landed before entering the turbulent wake *** simulating the approach of a tropical cyclone,additional CFD sensitivity tests were performed to study the impacts of building wake under extreme meteorological *** was found that,in a narrow range of prevalent wind directions with wind speeds larger than a certain threshold value,a substantial drop in wind speed(>3.6 m/s) along the glide path of aircraft was observed in the building *** CFD results also showed that under the most critical situation,a drop in wind speed as large as 6.4 m/s occurred right at the touchdown point of landing aircraft on the runway,an effect which may have a significant impact on aircraft *** study indicated that a comprehensive analysis of the potential impacts of building wake on aircraft operations should be carried out for airport terminals and associated buildings in airfields to ensure safe aviation operation under all meteorological conditions and to facilitate implementation of precautionary measures.

关键词： Aviation safety Building aerodynamics Computational fluid dynamics (CFD) k-e turbulence model Tropicalcyclone

An Observational Study of the Hygroscopic properties of Aerosols over the pearl River Delta Region

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An Observational Study of the Hygroscopic Properties of Aero...

An Observational Study of the Hygroscopic properties of Aerosols over the pearl River Delta Region

十一届全国气溶胶会议暨第十届海峡两岸气溶胶技术研讨会

作者： Haobo Tan Yan Yin Xuesong Gu Fei Li p.w.chan Hanbing Xu Xuejiao Deng Institute of Tropical and Marine Meteorology China Meteorological Administration Key Laboratory for Aerosol-cloud-precipitation of China Meteorological Administration Nanjing University of Information Science and Technology Hong Kong Observatory Experimental Teaching Center Sun Yat-sen University

Hygroscopic growth can significantly affect size distribution and activation of aerosol particles, as well as their effects on human health, atmospheric visibility, and climate. In this study, a H-TDMA（Hygroscopic Tandem Differential Mobility Analyzer） was utilized to measure hygroscopic growth factor and mixing state of aerosol particles at the CAwNET station in panyu, Guangzhou, China. A statistical analysis of the results show that, at relative humidity（RH） of 90%, for less-hygroscopic particles of 40-200 nm in diameter, the growth factor（g LH） was around 1.13, while the number fraction（NF LH） varied between 0.41±0.136 and 0.26±0.078;for more-hygroscopic particles, the growth factor（g MH） varied between 1.46 and 1.55 with the average equivalent ammonium sulfate ratio ranging from 0.63 to 0.68. The differences in AS among particle of different sizes reveal that more-hygroscopic inorganic salts, such as ammonium sulfate and ammonium nitrate, are of more effective condensation growth for Aitken mode particles. A combined analysis of the probability density function of growth factor（Gf-pDF） and simultaneous meteorological data shows that during clean periods with air masses moving from the north, the particles are more likely to have homogeneous chemical composition, while during polluted or pollution accumulation periods, variations in mean number weighted growth factor（g mean）and NF MH become more pronounced, indicating that locally-emitted aerosol particles tend to be in an externally mixed state and contain a certain proportion of less-hygroscopic particles. This study can help improve our understanding of aerosol hygroscopicity and its impact on the atmospheric visibility and environment.

关键词： H-TDMA aerosol hygroscopicity urban aerosol haze pearl River Delta

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An Observational Study of the Hygroscopic Properties of Aero...

第八届全国优秀青年气象科技工作者学术研讨会

作者： Haobo Tan Yan Yin Xuesong Gu Fei Li p.w.chan Hanbing Xu Xuejiao Deng Qilin wan Key Laboratory for Aerosol-cloud-precipitation of China Meteorological Administration Nanjing University of Information Science and Technology Key Laboratory of Regional Numerical weather prediction Institute of Tropical and Marine Meteorology China Meteorological Administration Hong Kong Observatory Experimental Teaching Center Sun Yat-sen University

Hygroscopic growth can significantly affect size distribution and activation of aerosol particles,as well as their effects on human health,atmospheric visibility,and *** this study,a H-TDMA（Hygroscopic Tandem Differential Mobility Analyzer）was utilized to measure hygroscopic growth factor and mixing state of aerosol particles at the CAwNET station in panyu,Guangzhou,China.A statistical analysis of the results show that,at relative humidity（RH）of 90%,for less-hygroscopic particles of 40-200 nm in diameter,the growth factor（gLH）was around 1.13,while the number fraction（NFLH）varied between 0.41±0.136 and 0.26±0.078;for more-hygroscopic particles,the growth factor（gMH）varied between 1.46 and 1.55 with the average equivalent ammonium sulfate ratio（εAS）ranging from 0.63 to *** differences inεAS among particle of different sizes reveal that more-hygroscopic inorganic salts,such as ammonium sulfate and ammonium nitrate,are of more effective condensation growth for Aitken mode particles.A combined analysis of the probability density function of growth factor（Gf-pDF）and simultaneous meteorological data shows that during clean periods with air masses moving from the north,the particles are more likely to have homogeneous chemical composition,while during polluted or pollution accumulation periods,variations in mean number weighted growth factor（gmean）and NFMH become more pronounced,indicating that locally-emitted aerosol particles tend to be in an externally mixed state and contain a certain proportion of less-hygroscopic *** study can help improve our understanding of aerosol hygroscopicity and its impact on the atmospheric visibility and environment.

关键词： H-TDMA aerosol hygroscopicity urban aerosol haze pearl River Delta

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基于奇异值分解的激光雷达湍流预警算法

光学精密工程 2019年第3期27卷 671-679页

作者：庄子波陈星台宏达宋德龙陈柏纬中国民航大学飞行技术学院天津300300 中国民航大学天津市空管运行规划与安全技术重点实验室天津300300 中国民航大学电子信息与自动化学院天津300300 香港天文台香港999077

提出了一种基于奇异值分解(Singular Value Decomposition,SVD)的湍流速度结构函数构造方法,将该方法构造的速度结构函数与湍流模型拟合,可以实现激光雷达的湍流识别。首先对激光雷达扫描的空间数据进行距离门扇区划分,在每个子扇区内... 详细信息

提出了一种基于奇异值分解(Singular Value Decomposition,SVD)的湍流速度结构函数构造方法,将该方法构造的速度结构函数与湍流模型拟合,可以实现激光雷达的湍流识别。首先对激光雷达扫描的空间数据进行距离门扇区划分,在每个子扇区内对湍流风场做奇异值分解,得到特征速度基准值和每个距离门的湍流脉动速度,构建出速度结构函数。选取标准von Kármán湍流模型函数作为拟合约束,得出涡流耗散率的立方根来判断湍流的强度。最后,利用兰州机场的实测数据,对比分析了在不同湍流强度下SVD方法的速度结构函数与局部平均方法的性能。通过与机组报告的湍流数据进行对比分析,SVD方法进行湍流预警的预警率可以达到85.2%。该方法对提高机场湍流探测和识别有重要意义。

关键词：激光雷达奇异值分解速度结构函数湍流

Human endogenous retrovirus type-w and multiple sclerosis–related smoldering neuroinflammation

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Neural Regeneration Research 2025年第3期20卷 813-814页

作者： Joel Gruchot Laura Reiche Andrew chan Robert Hoepner patrick Küry Department of Neurology Medical Faculty and University Hospital DüsseldorfHeinrich Heine University DüsseldorfDüsseldorfGermany Department of Neurology InselspitalBern University Hospital and University of BernBernSwitzerland

Introduction to human endogenous retrovirus type-w(HERV-w): Genomic inheritance from the past includes retroviral sequences that have been stably incorporated into our genomes and account for up to 8% of human DNA.

关键词： endogenous inflammation Human

A novel method for clustering cellular data to improve classification

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Neural Regeneration Research 2025年第9期20卷 2697-2705页

作者： Diek w.wheeler Giorgio A.Ascoli Center for Neural Informatics Structures&PlasticityKrasnow Institute for Advanced Study Bioengineering Department Volgenau School of Engineering George Mason University FairfaxVAUSA

Many fields,such as neuroscience,are experiencing the vast prolife ration of cellular data,underscoring the need fo r organizing and interpreting large datasets.A popular approach partitions data into manageable subsets via hierarchical clustering,but objective methods to determine the appropriate classification granularity are *** recently introduced a technique to systematically identify when to stop subdividing clusters based on the fundamental principle that cells must differ more between than within *** we present the corresponding protocol to classify cellular datasets by combining datadriven unsupervised hierarchical clustering with statistical *** general-purpose functions are applicable to any cellular dataset that can be organized as two-dimensional matrices of numerical values,including molecula r,physiological,and anatomical *** demonstrate the protocol using cellular data from the Janelia MouseLight project to chara cterize morphological aspects of neurons.

关键词： cellular data clustering dendrogram data classification Levene's one-tailed statistical test unsupervised hierarchical clustering

Genistein:a possible solution for the treatment of Alzheimer’s disease

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Neural Regeneration Research 2025年第10期20卷 2903-2905页

作者： Karolina pierzynowska Bartosz Karaszewski Grzegorz węgrzyn Department of Molecular Biology University of GdanskGdanskPoland Gdansk Polandand Department of Adult NeurologyFaculty of MedicineMedical University of GdanskGdanskPoland

Neurodegenerative diseases are defined as disorders resulting from the slow and progressive loss of function and eventual death of neural cells that result from the primary pathology of nervous *** can lead to severe nervous system dysfunction,eventually affecting multiple organs and *** hundred neurodegenerative diseases have been described,and owing to their prevalence,severity.

关键词： organs Alzheimer death