检索结果-南通市图书馆

Roles of Upper-Level Descending Inflow in Moat Development in Simulated Tropical Cyclones with Secondary Eyewall Formation

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第6期41卷 1100-1114页

作者： Nannan QIN liguang wu Nanjing Joint Institute for Atmospheric Sciences Nanjing 210041China Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China Innovation Center of Ocean and Atmosphere System Zhuhai Fudan Innovation Research InstituteZhuhai 518057China

This study investigated the effects of upper-level descending inflow(ULDI)associated with inner-eyewall convection on the formation of the moat in tropical cyclones(TCs)with secondary eyewall formation(SEF).In our numerical experiments,a clear moat with SEF occurred in TCs with a significant ULDI,while no SEF occurred in TCs without a significant *** eyewall convection developed more vigorously in the control run.A ULDI occurred outside the inner-eyewall convection,where it was symmetrically *** ULDI was initially triggered by the diabatic warming released by the inner eyewall and later enhanced by the cooling below the anvil *** ULDI penetrated the outer edge of the inner eyewall with relatively dry air and prevented excessive solid-phase hydrometeors from being advected further *** produced extensive sublimation cooling of falling hydrometeors between the eyewall and the outer *** sublimation cooling resulted in negative buoyancy and further induced strong subsidence between the eyewall and the outer *** a result,a clear moat was *** of the moat in the ongoing SEF prevented the outer rainband from moving farther inward,helping the outer rainband to symmetrize into an outer *** the sensitivity experiment,no significant ULDI formed since the eyewall convection was weaker,and the eyewall anvil developed relatively lower,meaning the formation of a moat and thus an outer eyewall was less *** study suggests that a better-represented simulation of inner-eyewall convective structures and distribution of the solid-phase hydrometeors is important to the prediction of SEF.

关键词： tropical cyclone secondary eyewall formation upper-level descending inflow eyewall convection

Alignment of Track Oscillations during Tropical Cyclone Rapid Intensification

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第4期41卷 655-670页

作者： Tong XIE liguang wu Yecheng FENG Jinghua YU Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science and TechnologyNanjing 210044China Dept.of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China CMA-FDU Joint Laboratory of Marine Meteorology Shanghai 200438China

Recent studies on tropical cyclone(TC)intensity change indicate that the development of a vertically aligned TC circulation is a key feature of its rapid intensification(RI),however,understanding how vortex alignment occurs remains a challenging topic in TC intensity change *** on the simulation outputs of North Atlantic Hurricane Wilma(2005)and western North Pacific Typhoon Rammasun(2014),vortex track oscillations at different vertical levels and their associated role in vortex alignment are examined to improve our understanding of the vortex alignment during RI of TCs with initial hurricane *** is found that vortex tracks at different vertical levels oscillate consistently in speed and direction during the RI of the two simulated *** the consistent track oscillation reduces the oscillation tilt during RI,the reduction of vortex tilt results mainly from the mean track before *** is also found that the vortex tilt is primarily due to the mean vortex track before and after *** track oscillations are closely associated with wavenumber-1 vortex Rossby waves that are dominant wavenumber-1 circulations in the TC inner-core *** study suggests that the dynamics of the wavenumber-1 vortex Rossby waves play an important role in the regulation of the physical processes associated with the track oscillation and vertical alignment of TCs.

关键词： tropical cyclone rapid intensification vortex tilt Rossby wave

在线全文

学校读者我要写书评

暂无评论

扩散年代学:进展与展望

地质学报 2024年第3期98卷 862-875页

作者：李扬吴黎光李献华造山带与地壳演化教育部重点实验室北京大学地球与空间科学学院北京100871 岩石圈演化国家重点实验室中国科学院地质与地球物理研究所北京100029

地质年代学为地球与行星科学研究提供时间坐标,以定量解析地质过程先后关系和时间尺度。历经百余年发展,定年技术在研究对象、测试效率、空间分辨率和时间分辨率等维度均得到大幅度提高,地质年代学研究已从仅提供时代约束过渡到更加强... 详细信息

地质年代学为地球与行星科学研究提供时间坐标,以定量解析地质过程先后关系和时间尺度。历经百余年发展,定年技术在研究对象、测试效率、空间分辨率和时间分辨率等维度均得到大幅度提高,地质年代学研究已从仅提供时代约束过渡到更加强调对地质过程时间尺度与节律的研究,进而约束地质事件的驱动机制和互馈机理。然而,基于放射性同位素衰变的绝对定年技术精度存在物理极限,不能无限提高,且其时间分辨率一般随年龄增加而变差,难以满足深时地质研究的高时间分辨率需求,发展时间分辨率不受绝对年龄约束的相对定年技术是地质年代学的重要发展方向。本文围绕扩散年代学这一具有重要发展前景的相对定年技术,在系统回顾其理论模型和测量技术的基础上,重点对制约扩散年代学准确性和精确性的问题,如扩散系数的不确定性、扩散初始条件假设、浓度曲线的测试质量以及误差评估等进行了探讨。本文还对扩散年代学近年来在岩浆储存与运移、成矿时间尺度与节律和变质过程等领域取得的部分重要进展予以评述。精确的扩散系数是开展扩散年代学研究的前提,以石英中的Ti为例,不同实验给出的扩散系数差异超过3个数量级,据此计算的花岗岩岩浆在固相线上的储存时间从几十年变化到百万年尺度,显著影响我们对岩浆储存状态的理解。高质量的元素浓度剖面测量是扩散年代学的关键,因石英Ti含量的高空间分辨率精准测量较为困难,CL灰度常被作为Ti含量的替代指标,但这需要考虑Al等元素对CL灰度的影响,并严格评估Ti含量校正曲线和扩散剖面空间尺度不匹配对定年结果的影响。高温变质过程U-Pb定年通常给出较为离散的表观年龄,并被解释为变质过程具有较长的持续时间,这一定程度上可以通过高温下同位素体系因扩散引起的不封闭予以解释。展望未来,进一步完善扩散年代学在高温体系中的研究,拓展在中低温条件下的应用,并与绝对定年深度结合,是扩散年代学的重要发展方向,也是实现深时地质研究高时间分辨率解析的必由之路。

关键词：相对定年时间分辨率扩散系数

有机配体结构对ZIFs材料结晶度及其CO_(2)吸附性能的影响机制

在线全文

学校读者我要写书评

暂无评论

环境科学学报 2024年第8期44卷 110-121页

作者：刘晗翀吴梦雅吴礼光王挺浙江工商大学环境科学与工程学院杭州310012

沸石咪唑酯框架(ZIFs)被认为是一种用于高效CO_(2)捕获的多孔晶体材料,其晶体结构是影响CO_(2)吸附性能的关键因素之一.本文分别选用2-甲基咪唑、2-乙基咪唑和3-氨基-1,2,4-三唑作为有机配体,通过反相微乳液制备了ZIFs材料用于CO_(2)的... 详细信息

沸石咪唑酯框架(ZIFs)被认为是一种用于高效CO_(2)捕获的多孔晶体材料,其晶体结构是影响CO_(2)吸附性能的关键因素之一.本文分别选用2-甲基咪唑、2-乙基咪唑和3-氨基-1,2,4-三唑作为有机配体,通过反相微乳液制备了ZIFs材料用于CO_(2)的捕获.结合ZIFs材料结构表征、气体吸附、巨正则蒙特卡洛(GCMC)以及分子动力学(MD)模拟,研究了有机配体对ZIFs的结晶度、孔结构和CO_(2)吸附性能的影响.结果表明:采用2-甲基咪唑合成的ZIF-8-M与2-乙基咪唑合成的ZIF-8-N,两者除了结晶度外其它结构差异并不十分显著,但ZIF-8-M材料CO_(2)吸附容量较高,可达0.69 mmol·g^(-1);ZIF-8-N结晶度、比表面积和孔隙率较小,CO_(2)吸附容量也较低,仅为0.29 mmol·g^(-1).提高合成温度,ZIF-8-M和ZIF-8-N结晶度均明显增大,CO_(2)吸附容量也显著提高,这可能是由于高结晶度的ZIFs更有利于氢键的形成和π-π堆积作用的发生.当温度从30℃升高到60℃时,ZIF-8-M的CO_(2)吸附容量提高了2.2倍,ZIF-8-N的CO_(2)吸附容量增大了4.9倍.此外,GCMC和MD模拟结果表明:随着晶体结构无序化程度的增加,ZIF-8-M对CO_(2)分子的吸附能由-52.5 kcal·mol^(-1)增大至511.0 kcal·mol^(-1),吸附能力下降,吸附的CO_(2)分子个数明显下降.再次验证了结晶度是影响ZIFs材料吸附CO_(2)性能的关键结构参数.

关键词：反相微乳液 ZIF-8 结晶度 CO_(2)吸附分子动力学模拟

不同非对称介孔碳掺杂的混合基质膜分离CO_(2)性能的提升机制

在线全文

学校读者我要写书评

暂无评论

环境科学学报 2024年第6期44卷 318-329页

作者：王沛张珂王挺吴礼光李春娟浙江工商大学环境科学与工程学院杭州310012

为了阐明膜分离CO_(2)性能提升机制,以浸渍碳化-硬模板法制备的非对称介孔碳材料作为掺杂组分,通过原位聚合法构建不同聚酰亚胺(Polyimide,PI)混合基质膜.同时,结合气体吸附及渗透实验系统研究了不同非对称介孔碳材料掺杂后对混合基质... 详细信息

为了阐明膜分离CO_(2)性能提升机制,以浸渍碳化-硬模板法制备的非对称介孔碳材料作为掺杂组分,通过原位聚合法构建不同聚酰亚胺(Polyimide,PI)混合基质膜.同时,结合气体吸附及渗透实验系统研究了不同非对称介孔碳材料掺杂后对混合基质膜分离CO_(2)性能提升机制.结果表明,多次浸渍碳化过程使碳材料中无序结构转变为规则孔道结构.非对称结构可以在介孔碳材料中引入丰富的晶体缺陷结构,从而使材料中产生很多可以与CO_(2)分子形成强作用的C原子sp2和sp3杂化,因此,各个非对称介孔碳材料都具有优异的CO_(2)吸附性能.浸渍碳化次数过多碳材料中孔道变得更为紧致和规则,晶体缺陷结构减少,导致材料对CO_(2)气体吸附性能下降.低掺杂量非对称介孔碳的加入不能显著提升膜分离中CO_(2)溶解性能.但C原子sp2和sp3杂化作为CO_(2)的主要捕获中心,在膜中形成CO_(2)促进扩散过程,从而显著提升混合基质膜对CO_(2)的扩散选择性.非对称介孔碳材料掺杂后混合基质膜的最优CO_(2)/N2选择性可达40,接近纯PI膜的10倍,超过CMK-3构建的混合基质膜的2倍.

关键词：非对称介孔碳聚酰亚胺混合基质膜 CO_(2)吸附气体渗透性 CO_(2)促进扩散

Influence of Future Tropical Cyclone Track Changes on Their Basin-Wide Intensity over the Western North Pacific: Downscaled CMIP5 Projections

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2015年第5期32卷 613-623页

作者： WANG Chao wu liguang Earth System Modeling Center and Pacific Typhoon Research Center Key Laboratory of Meteorological Disaster of the Ministry of Education Nanjing University of Information Science and Technology

The possible changes of tropical cyclone（TC） tracks and their influence on the future basin-wide intensity of TCs over the western North Pacific（WNP） are examined based on the projected large-scale environments derived from a selection of CMIP5（Coupled Model Intercomparison Project Phase 5） models. Specific attention is paid to the performance of the CMIP5 climate models in simulating the large-scale environment for TC development over the WNP. A downscaling system including individual models for simulating the TC track and intensity is used to select the CMIP5 models and to simulate the TC activity in the *** assessment of the future track and intensity changes of TCs is based on the projected large-scale environment in the21 st century from a selection of nine CMIP5 climate models under the Representative Concentration Pathway 4.5（RCP4.5）scenario. Due to changes in mean steering flows, the influence of TCs over the South China Sea area is projected to decrease,with an increasing number of TCs taking a northwestward track. Changes in prevailing tracks and their contribution to basin-wide intensity change show considerable inter-model variability. The influences of changes in prevailing track make a marked contribution to TC intensity change in some models, tending to counteract the effect of SST warming. This study suggests that attention should be paid to the simulated large-scale environment when assessing the future changes in regional TC activity based on climate models. In addition, the change in prevailing tracks should be considered when assessing future TC intensity change.

关键词： tropical cyclone track and intensity climate change downscaling CMIP5

Re-examination of Tropical Cyclone Formation in Monsoon Troughs over the Western North Pacific

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2015年第7期32卷 924-934页

作者： ZONG Huijun wu liguang Pacific Typhoon Research Center and Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science and Technology State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences

The monsoon trough （MT） is one of the large-scale patterns favorable for tropical cyclone （TC） formation over the western North Pacific （WNP）. This study re-examines TC formation by treating the MT as a large-scale background for TC activity during May-October. Over an 11-year （2000-10） period, 8.3 TC formation events on average per year are identified to occur within MTs, accounting for 43.1% of the total TC formation events in the WNP basin. This percentage is much lower than those reported in previous studies. Further analysis indicates that TC formation events in monsoon gyres were included at least in some previous studies. The MT includes a monsoon confluence zone where westerlies meet easterlies and a monsoon shear line where the trade easterlies lie north of the monsoon westerlies. In this study, the large-scale flow pattern associated with TC formation in the MT is composited based on the reference point in the confluence zone where both the zonal and meridional wind components are zero with positive vorticity. While previous studies have found that many TCs form in the confluence zone, the composite analysis indicates that nearly all of the TCs formed in the shear region, since the shear region is associated with stronger low-level relative vorticity than the confluence zone. The prevailing easterly vertical shear of zonal wind and barotropic instability may also be conducive to TC formation in the shear region, through the development of synoptic-scale tropical disturbances in the MT that are necessary for TC formation.

关键词： monsoon trough tropical cyclone formation summer monsoon vertical wind shear

Quantifying the Contribution of Track Changes to Interannual Variations of North Atlantic Intense Hurricanes

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2022年第2期39卷 260-271页

作者： Jun LU liguang wu Shunwu ZHOU Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Joint Center for Data Assimilation Research and ApplicationsNanjing University of Information Science and TechnologyNanjing 210031China Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200433China Innovation Center of Ocean and Atmosphere System Zhuhai Fudan Innovation Research InstituteZhuhai 518057China

Previous studies have linked interannual variability of tropical cyclone(TC)intensity in the North Atlantic basin(NA)to Sahelian rainfall,vertical shear of the environmental flow,and relative sea surface temperature(SST).In this study,the contribution of TC track changes to the interannual variations of intense hurricane activity in the North Atlantic basin is evaluated through numerical *** is found that that observed interannual variations of the frequency of intense hurricanes during the period 1958–2017 are dynamically consistent with changes in the large-scale ocean/atmosphere *** changes can account for~50%of the interannual variability of intense hurricanes,while no significant difference is found for individual environmental parameters between active and inactive *** only significant difference between active and inactive years is in the duration of TC intensification in the region east of 60°*** duration increase is not due to the slow-down of TC *** active years,a southeastward shift of the formation location in the region east of 60°W causes TCs to take a westward prevailing track,which allows TCs to have a longer opportunity for *** the other hand,most TCs in inactive years take a recurving track,leading to a shorter duration of *** study suggests that the influence of track changes should be considered to understand the basin-wide intensity changes in the North Atlantic basin on the interannual time scale.

关键词： interannual variations intense hurricanes track changes vertical shear

Characteristics of extreme rainfall and rainbands evolution of Super Typhoon Lekima (2019) during its landfall

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2022年第1期16卷 64-74页

作者： Chunyi XIANG liguang wu Nannan QIN Key Laboratory of Meteorological Disaster(Ministry of Education) Nanjing University of Information Science and TechnologyNanjing 210044China National Meteorological Center Beijing 100081China Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200433China

As one of the most devastating tropical cyclones over the western North Pacific Ocean,Super Typhoon Lekima(2019)has caused a wide range of heavy rainfall in *** on the CMA Multi-source merged Precipitation Analysis System(CMPAS)-hourly data set,both the temporal and spatial distribution of extreme rainfall is *** is found that the heavy rainfall associated with Lekima includes three main episodes with peaks at 3,14 and 24 h after landfall,*** first two rainfall episodes are related to the symmetric outburst of the inner rainband and the persistence of outer *** third rainfall episode is caused by the influence of cold,dry air from higher latitudes and the peripheral circulation of the warm moist tropical *** averaged rainrate of inner rainbands underwent an obvious outburst within 6 h after *** asymmetric component of the inner rainbands experienced a transport from North(West)quadrant to East(South)quadrant after landfall which was related to the storm motion other than the Vertical Wind Shear(VWS).Meanwhile the outer rainband in the vicinity of three times of the Radius of Maximum Wind(RMW)was active over a 12-h period since the decay of the inner *** asymmetric component of the outer rainband experienced two significant cyclonical migrations in the northern semicircle.

关键词： extreme rainfall rainband evolution landfalling tropical cyclone