检索结果-南通市图书馆

Atmospheric and Oceanic Science Letters 2014年第4期7卷 334-339页

作者： ZHU Jiang-Shan kong fan-you LEI Heng-Chi Institute of Atmospheric Physics Chinese Academy of Sciences Center for Analysis and Prediction of Storms University of Oklahoma

A running mean bias （RMB） correction ap- proach was applied to the forecasts of near-surface variables in a seasonal short-range ensemble forecasting experiment with 57 consecutive cases during summer 2010 in the northern China region. To determine a proper training window length for calculating RMB, window lengths from 2 to 20 days were evaluated, and 16 days was taken as an optimal window length, since it receives most of the benefit from extending the window length. The raw and 16-day RMB corrected ensembles were then evaluated for their ensemble mean forecast skills. The results show that the raw ensemble has obvious bias in all near-surface variables. The RMB correction can remove the bias reasonably well, and generate an unbiased ensemble. The bias correction not only reduces the ensemble mean forecast error, but also results in a better spreaderror relationship. Moreover, two methods for computing calibrated probabilistic forecast （PF） were also evaluated through the 57 case dates： 1） using the relative frequency from the RMB-eorrected ensemble; 2） computing the forecasting probabilities based on a historical rank histogram. The first method outperforms the second one, as it can improve both the reliability and the resolution of the PFs, while the second method only has a small effect on the reliability, indicating the necessity and importance of removing the systematic errors from the ensemble.

关键词： short-range ensemble forecast bias-corrected ensemble forecast running mean bias correction near-surface variable forecast

Cloud Seedability Study with a Dual-Model System

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2013年第4期6卷 197-202页

作者： JIN Ling LEI Heng-Chi kong fan-you YANG Jie-fan HU Zhao-Xia Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Center for Analysis and Prediction of Storms University of Oklahoma

In this research, one-dimensional stratiform a novel dual-model system, cold cloud model （1DSC） coupled to Weather Research and Forecast （WRF） model （WRF-1DSC for short）, was employed to investigate the effects of cloud seeding by silver iodide （AgI） on rain enhancement. Driven by changing environmental conditions extracted from the WRF model, WRF-1DSC could be used to assess the cloud seeding effects quantitatively. The employment of WRF- 1DSC, in place of a one-dimen- sional two-moment cloud seeding model applied to a three-dimensional mesoscale cloud-resolving model, was found to result in massive reduction of computational resources. Numerical experiments with WRF-1DSC were conducted for a real stratiform precipitation event ob- served on 4-5 July 2004, in Northeast China. A good agreement between the observed and modeled cloud system ensured the ability of WRF-1DSC to simulate the observed precipitation process efficiently. Sensitivity tests were performed with different seeding times, locations, and amounts. Experimental results showed that the optimum seeding effect （defined as the percentage of rain enhancement or rain enhancement rate） could be achieved through proper seeding at locations of maximum cloud water content when the updraft was strong. The optimum seeding effect was found to increase by 5.61% when the cloud was seeded at 5.5 km above ground level around 2300 UTC 4 July 2004, with the maximum AgI mixing ratio （As） equaling 15 ng kg-1. On the other hand, for an overseeded cloud, a significant reduction occurred in the accumulated precipitation （-12.42%） as Xs reached 100 ng kg^-1. This study demonstrates the potential of WRF- 1DSC in determining the optimal AgI seeding strategy in practical operations of precipitation enhancement.

关键词： dual-model system AgI cloud seeding WRF clmld model

Analysis of Deep Convective Towers in a Southwest-Vortex Rainstorm Event

在线全文

学校读者我要写书评

暂无评论

Journal of Tropical Meteorology 2021年第2期27卷 177-190页

作者： ZHAI Dan-hua kong fan-you DAI Ze-jun GAO Song DENG Cheng-zhi ZHANG Yong Chongqing Meteorological Observatory Chongqing 401147 China Center for Analysis and Prediction of Storms University of OklahomaNorman 73072 USA Hunan Meteorological Observatory Changsha 410118 China Chongqing Institute of Meteorological Sciences Chongqing 401147 China

The structure and organization of the extreme-rain-producing deep convection towers and their roles in the formation of a southwest vortex(SWV)event are studied using the intensified surface rainfall observations,weather radar data and numerical simulations from a high-resolution convection-allowing *** deep convection towers occurred prior to the emergence of SWV and throughout its onset and development *** largely resemble the vortical hot tower(VHT)commonly seen in typhoons or hurricanes and are thus considered as a special type of VHT(sVHT).Each sVHT presented a vorticity dipole structure,with the upward motion not superpose the positive vorticity.A positive feedback process in the SWV helped the organization of sVHTs,which in turn strengthened the initial disturbance and development of *** meso-γ-scale large-value areas of positive relative vorticity in the mid-toupper troposphere were largely induced by the diabatic heating and *** strong mid-level convergence was attributed to the mid-level vortex *** low-level vortex intensification was mainly due to low-level convergence and the stretching of upward *** meso-α-scale large-value areas of positive relative vorticity in the low-level could expand up to about 400 hPa,and gradually weakened with time and height due to the decaying low-level convergence and vertical stretching in the matured *** the SWV matured,two secondary circulations were formed,with a weaker mean radial inflow than the outflow and elevated to 300-400 hPa.

关键词： southwest vortex deep convective towers diabatic heating secondary circulations heavy rain

在线全文

学校读者我要写书评

暂无评论

基于增长模繁殖法的风暴尺度集合预报试验

高原气象 2010年第2期29卷 429-436页

作者：高峰闵锦忠孔凡铀南京信息工程大学大气科学学院江苏南京210044 南京信息工程大学气象灾害省部共建教育部重点实验室江苏南京210044 Center for Analysis and Prediction of Storms/The University of Oklahoma Norman OK 73072 USA

利用WRFV2.2模式,对1977年5月20日发生在美国俄克拉荷马州的典型超级单体风暴进行风暴尺度集合预报试验。通过对比由Monte-Carlo法和增长模繁殖法构造的集合预报系统的性能,检验了增长模繁殖法应用于风暴尺度集合预报的合理性及其价值... 详细信息

利用WRFV2.2模式,对1977年5月20日发生在美国俄克拉荷马州的典型超级单体风暴进行风暴尺度集合预报试验。通过对比由Monte-Carlo法和增长模繁殖法构造的集合预报系统的性能,检验了增长模繁殖法应用于风暴尺度集合预报的合理性及其价值。研究表明,在预报误差的意义上,集合技术能够明显改善中尺度强对流天气的单一确定性预报;但纯统计意义的Monte-Carlo法动力意义不足,导致集合离散度偏低;作为改进方法,增长模繁殖法充分考虑了预报中误差增长的信息,改善了离散度增长偏慢的缺陷。研究结果还显示,增长模繁殖法构造的集合预报系统的各预报评分(RSS、ETS等)均高于Monte-Carlo法,体现了增长模繁殖法的显著优势,但不同的繁殖周期对非降水场和降水场的预报能力有所差异,合理的繁殖周期需要在两者之间寻求平衡点。

关键词：风暴尺度集合预报 Monte-Carlo法增长模繁殖法

在线全文

学校读者我要写书评

暂无评论

碎石化施工技术在混凝土路面大修中的应用

西部交通科技 2018年第6期 89-91页

作者：孔凡友广西壮族自治区岑溪公路管理局广西岑溪543200

文章介绍了碎石化施工技术所采用的相关机械设备,分析了碎石化施工技术的应用原理,并结合工程实例,阐述了碎石化施工技术应用于水泥混凝土路面大修工程的工艺要点。

关键词：碎石化施工技术水泥混凝土路面大修应用

Cloning and Characterization of a Family of Disease Resistance Gene Analogs from 6VS of Haynaldia villosa

在线全文

学校读者我要写书评

暂无评论

Agricultural Sciences in China 2003年第8期2卷 937-942页

作者： kong fan-jing, MA you-zhi, CHEN Xiao and XIN Zhi-yong(Institute of Crop Breeding and Cultivation , Chinese Academy of Agricultural Sciences , Beijing 100081,P. R. China Open Laboratory of Saline Lake Resources and Environment of Ministryof Land and Resources , Beijing 100037 , P.R. China) Institute of Crop Breeding and Cultivation Chinese Academy of Agricultural Sciences Beijing 100081P.R. China Open Laboratory of Saline Lake Resources and Environment of Ministry of Land and Resources Beijing 100037 P.R. China Institute of Crop Breeding and Cultivation Chinese Academy of Agricultural Sciences Beijing 100081P.R. China

In the present study, microdissection of 6VS and the cloning of the resistance gene analogs(RGA)from them were reported. The 6VS were microdissected with needle and 10 types of resistance gene analogs were obtained by PCR with degenerate oligonucleotide primer designed according to resistance genes. They were designated as Hvrgak1-Hvrgak10, GenBank accession numbers are AF387113-AF387121, AY040671- AY040672. Identity among RGAs was about 10-50%, and identity with cloned R gene from plants was 5-20%. Southern hybridization analysis results showed 3 RGAs, Hvrgak2, Hvrgak4, and Hvr-gak5 were linked with wheat powdery mildew resistance. These RGAs may be used as direct entrance or probes for cloning the disease resistance genes.

关键词： 6VS of Haynaldia Villosa Microdissection Resistance gene analogs(RGA) Cloning

在线全文

学校读者我要写书评

暂无评论

350t落下孔车组装工艺

机车车辆工艺 2005年第5期 5-6,11页

作者：孔凡友张涛中铁十九局集团第四工程有限公司辽宁辽阳111200 齐齐哈尔铁路车辆(集团)有限责任公司黑龙江齐齐哈尔161002

通过对350 t落下孔车结构及制造难点的分析,制定合理的组装工艺。

关键词：长大落下孔车、组装、工艺

在线全文

学校读者我要写书评

暂无评论

风暴尺度集合成员数对预报技巧的影响

南京气象学院学报 2009年第2期32卷 215-221页

作者：高峰闵锦忠孔凡铀王雪莉南京信息工程大学大气科学学院江苏南京210044 南京信息工程大学气象灾害省部共建教育部重点实验室江苏南京210044 Center for Analysis and Prediction of Storms/The University of Oklahoma Norman OK 73072 USA 通信指挥学院军队信息化建设教研室湖北武汉430010

利用WRFV2.2模式,对1977年5月20日发生在美国Oklahoma的典型超级单体风暴进行集合预报试验。采用蒙特卡洛法对不同区域初值扰动,对比分析成员个数的变化对预报技巧的影响,检验集合技术应用于风暴尺度系统的可行性及应用价值。结果显示,... 详细信息

利用WRFV2.2模式,对1977年5月20日发生在美国Oklahoma的典型超级单体风暴进行集合预报试验。采用蒙特卡洛法对不同区域初值扰动,对比分析成员个数的变化对预报技巧的影响,检验集合技术应用于风暴尺度系统的可行性及应用价值。结果显示,基于WRFV2.2模式的风暴尺度集合预报（storm-scale ensemble forecasting,SSEF）能够从热力场和动力场上改善单一确定性预报,并成功预报极端降水,表明SSEF具有较高的应用和研究价值;总体上预报技巧随成员数增加而增加,当集合成员数达到5-13时,预报技巧呈饱和特征,不同变量、不同扰动区域时的饱和成员数略有差异。

关键词：集合预报风暴尺度饱和成员数

高密度电阻率法在铧尖子水库大坝渗漏隐患探测中的应用

在线全文

学校读者我要写书评

暂无评论

广东水利水电 2008年第6期 13-15,18页

作者：孔繁友郭伟贺清录辽宁省水利水电科学研究院辽宁沈阳110003

该文详细介绍了高密度电阻率法在辽宁省铧尖子水库大坝隐患探测中的应用,为水库除险加固设计提供了可靠依据。实践表明,该探测技术应用在大坝渗漏隐患探测中,具有快速高效、稳定性好、操作简便、探测结果可靠等优点。

关键词：高密度电阻率大坝渗漏隐患综合物探钻探验证

Test on Stochastic Block Model:Local Smoothing and Extreme Value Theory

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2022年第4期35卷 1535-1556页

作者： WU fan kong Xinbing XU Chao School of Mathematics Southeast UniversityNanjing211819China School of Statistics and Mathematics Nanjing Audit UniversityNanjing211815China School of Information Engineering Nanjing Audit UniversityNanjing211815China

In this paper,to obtain a consistent estimator of the number of communities,the authors present a new sequential testing procedure,based on the locally smoothed adjacency matrix and the extreme value *** the null hypothesis,the test statistic converges to the type I extreme value distribution,and otherwise,it explodes fast and the divergence rate could even reach n in the strong signal case where n is the size of the network,guaranteeing high detection *** method is simple to use and serves as an alternative approach to the novel one in Lei(2016)using random matrix *** detect the change of the community structure,the authors also propose a two-sample test for the stochastic block model with two observed adjacency *** studies justify the *** authors apply the proposed method to the political blog data set and find reasonable group structures.

关键词： Extreme value distribution network data stochastic block model