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1.
基于多源观测资料和再分析资料,采用天气学诊断分析方法研究了2019年5月长江中下游地区发生的一次致洪暴雨的特征及主要成因。结果表明:该次极端致洪暴雨过程是在稳定的“西低东高”天气形势下,由持续时间长的短时强降水累积而成,具有明显的中尺度和阶段性特征。直接造成极端暴雨的中尺度对流系统在低空急流前沿不断新生东移,表现出明显的“列车效应”和准静止特点。过程中低空急流和超低空急流异常强盛,为极端暴雨提供了持续有利的水汽和对流不稳定条件,特别是整层高湿、较低的抬升凝结高度和较大暖云层厚度有利于提高降水效率,产生雨强较大的短时强降水;高低空急流耦合是强降水发生发展的重要动力机制,强垂直风切变区与暴雨落区有较好的对应。 相似文献
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基于城市投入产出指标,采用超效率DEA、Malmquist指数和耦合度分析法,对长江经济带110个城市的城市投入产出效率及其与生态环境的耦合关系进行研究,结果显示:1) 2001年~2015年上海在城市资源要素投入产出效率方面明显优于其他城市.攀枝花、六盘水等一些工业城市的城市效率得分低于0.626.城市效率相对低的城市主要由川西北、皖南等地分布转移到川西南、鄂北等地区分布.2) 从时空格局演变看,2001年~2015年间长江经济带城市的tfpch值平均每年提升0.8%.长江下游沿海地区城市和多数沿江城市的tfpch值要明显大于其他城市.3) 攀枝花、马鞍山等资源型城市的生态环境得分最低,并且得分逐年下降,表明在资源开发时对当地的生态环境破坏较为严重.整体上,长江经济带城市的生态环境状况呈现先恶化后稳定的状态.4) 从时空格局演变看,2001年~2015年长江经济带的城市投入产出与生态环境耦合协调性呈现先降低后升高的态势.低度耦合型城市由长江中下游的湘北、苏北等地区转移到鄂西北、湘南等地区. 相似文献
3.
三峡工程蓄水前后长江中下游环境流特征变化研究 总被引:1,自引:0,他引:1
环境流是为保障河流生态系统健康发展、河流生态功能得以恢复的一种水文情势过程.三峡水利工程的建设,也改变了长江的天然水文情势,也直接或间接影响该流域重要生物资源,改变生物群落的结构组成分布等,从而对长江中下游一定范围内的生态与环境带来深远影响.基于IHA分析法,研究三峡蓄水前后长江中下游的生态水文特征变化及环境流指标变化.结果表明:长江中下游4个水文站的环境流组成在三峡蓄水前后呈不同程度的变化;环境流组成也逐渐趋于单一化,各水文站的流量事件以枯水流量事件和高脉冲流量事件为主;三峡蓄水对大、小洪水事件和特枯流量事件的影响较为显著;三峡工程运行对长江中下游生态水文指标和环境流指标的影响,整体上表现出随着离三峡大坝距离的增加而有不同程度减弱的趋势;沿程汉江支流的汇入,以及洞庭湖、鄱阳湖对长江干流水文情势的调蓄作用在一定程度上缓解了三峡蓄水带来的影响. 相似文献
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基于非期望产出的超效率SBM-DEA模型,评价了 2007-2017年长江经济带108个城市的大气污染排放效率.通过耦合协调度模型和Tobit模型,验证了该区域产业结构变迁与大气污染排放效率的影响关系,结果发现:(1)仅有6个城市的大气污染排放效率均值达效率前沿面,大气污染排放效率均值从高到低依次为下游、中游和上游地区... 相似文献
6.
长三角区域酸雨类型转变趋势研究 总被引:1,自引:0,他引:1
[目的]酸雨是人类面临的重要环境问题,而我国长三角区域已成为全球重要酸雨影响地区之一.目前,我国已对SO2排放进行了有效控制,但随着氮氧化物排放量显著增多,氮沉降问题逐渐加剧.为此,探究长三角区域的酸雨类型转变趋势,为现在及将来酸雨危害严重地区森林生态系统恢复和可持续经营发展提供理论依据.[方法]将长三角区域作为研究对... 相似文献
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研究长江经济带运动休闲特色小镇的空间分布及影响因素,对促进长江经济带的发展具有重要意义.该文以长江经济带42个运动休闲特色小镇为研究对象,运用地理集中指数、核密度指数、区域重心法等方法探究了其空间分布特征;并从资源禀赋、GDP与人口、交通、区域竞技体育实力等方面,基于地理联系率与皮尔逊相关系数,研究了其影响因素.结果显示:长江经济带运动休闲特色小镇呈现集中分布状态,主要分布在三大城市群,分布重心位于湖北省与湖南省交界的长江干流,类型分布数量从多到少依次为娱乐型、赛事型、健康型、文化民俗型、智能制造型与培训型;影响因素方面,运动休闲特色小镇的创建依赖于适宜的资源禀赋、适中的经济基础、较高的交通通达度、以及靠近长江干流,与区域体育竞技实力相关性较小.依据分析结果,结合长江经济带发展提出关于运动休闲特色小镇建设的建议. 相似文献
8.
枯水年和平水年调水均加重了长江口南支、南港上段的盐水入侵强度,丰水年调水600m3/s、1000m3/s、1500m3/s对长江口南支宝钢河段、南港高桥河段水域的盐水入侵强度无影响.特枯水文年即使只调水600m3/s,对长江河口南支、南港河段盐水入侵就造成严重影响.建议枯水年枯季调水最好不要超过1000m3/s;平水年调水最好不要超过2000m3/s.另外,不同特征水文年调水对长江南港高桥站的盐水入侵强度的影响程度比对南支宝钢河段盐水入侵强度的影响要小. 相似文献
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SHRIMP zircon U-Pb dating for volcanic rocks of the Dasi Formation in southeast Hubei Province, middle-lower reaches of the Yangtze River and its implications 总被引:13,自引:0,他引:13
Guiqing Xie Jingwen Mao Ruiling Li Shaodong Zhou Huishou Ye Quanren Yan Zusong Zhang 《科学通报(英文版)》2006,51(24):3000-3009
The Jinniu Basin in southeast Hubei,located at the westernmost part of middle-lower val-ley of the Yangtze River,is one of the important vol-canic basins in East China. Volcanic rocks in the Jin-niu Basin are distributed mainly in the Majiashan Formation,the Lingxiang Formation and the Dasi Formation,consisting of rhyolite,basalt and basaltic andesite,(trachy)-basalt and basaltic trachy-andesite and (trachy)-andesite and (trachy)-dacite and rhyolite respectively,in which the Dasi volcanism is volumet-rically dominant and widespread. The Dasi volcanic rocks were selected for SHRIMP zircon U-Pb dating to confirm the timing of volcanism. The results indi-cate that there exist a large amount of magmatic zir-cons characterized by high U and Th contents in the volcanic rocks. The concordia ages for 13 points are 128 ± 1Ma (MSWD = 3.0). On account of the shape of zircons and Th/U ratios,this age is considered to represent the crystallization time of the Dasi volcan-ism. The volcanic rocks in the Dasi,Majiashan and Lingxiang Formations share similar trace elementand REE partition patterns as well as Sr-Nd isotopic compositions. In combination with the regional geol-ogy,it is proposed that the southeast Hubei volcanic rocks were formed mainly during the Early Creta-ceous,just like other volcanic basins in middle-lower Yangtze valley. A lithospheric extension is also sug-gested for tectonic regime in this region in the Cre-taceous Period. 相似文献
10.
2003年夏季江淮特大暴雨成因分析 总被引:3,自引:0,他引:3
利用全球NCEP/NCAR资料,采用诊断分析方法,对2003年夏季6月29日~7月4日发生在淮河流域的特大暴雨过程成因进行了分析,结果表明:暴雨出现与大气环流异常以及水汽输送、西南季风的异常偏强有关;暴雨区的水汽来源于阿拉伯海至孟加拉湾及北太平洋至中国南海地区。 相似文献
11.
南秦岭前寒武纪岩浆构造事件与地壳生长 总被引:6,自引:0,他引:6
前寒武纪构造体制与地球动力学机制是当前南秦岭构造带研究的薄弱环节,利用南秦岭广泛分布的前寒武纪岩石地层、岩浆-构造事件,尤其是记录前寒武纪地壳生长、演化及其地幔动力学机制的岩浆构造事件,对南秦岭前寒武纪地质体、岩浆活动、构造事件的组成、特征与年代学进行了综合研究。结果表明:南秦岭太古代类似于华北太古代地幔的特征;元古代地幔则发生了先亏损后富集的演化;其中,8-9亿年南秦岭发生了急剧的地壳生长事件,并以垂向加积增生为主要机制。 相似文献
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Recent temperature increase recorded in an ice core in the source region of Yangtze River 总被引:3,自引:4,他引:3
KANG ShiChang ZHANG YongJun QIN DaHe REN JiaWen ZHANG QiangGong Bjorn GRIGHOLM Paul A. MAYEWSKI 《科学通报(英文版)》2007,52(6):825-831
Interests on climate change in the source region of Yangtze River have been raised since it is a region with the greatest warming over the Tibetan Plateau (TP). A 70-year history of precipitation δ~(18)O has been recovered using an ice core record retrieved in a plat portion of the firn area in the Guoqu Glacier (33°34′37.8″N, 91°10′35.3″E, 5720 m a.s.l.), Mt. Geladaindong (the source region of Yangtze River), in November, 2005. By using a significant positive relationship between ice core δ~(18)O record and summer air temperature (July to September) from the nearby meteorological stations, a history of summer air temperature has been reconstructed for the last 70 years. Summer temperature was relatively low in 1940s and high in 1950s to the middle of 1960s. The lowest temperature occurred in the middle of 1970s. Temperature was low in 1980s and dramatically increased since 1990s, keeping the trend to the begin-ning of the 21st century. The warming rate recorded in the ice core with 0.5℃/10 a since 1970s is much higher that that in the central TP and the Northern Hemisphere (NH), and it becomes 1.1℃/10 a since 1990s which is also higher than these from the central TP and the NH, reflecting an accelerated warm-ing and a more sensitive response to global warming in the high elevation region. 相似文献
13.
CO_2排放量与经济发展之间的动态关系是低碳经济建设中的重要指标.长江经济带是我国"三大支撑带"之一,对长江经济带CO_2排放与经济发展之间的动态关系进行研究非常必要.基于Tapio脱钩模型和改进的加权因素分解模型,对长江经济带1995~2013年经济发展与能源消费起源CO_2排放之间的脱钩关系及其驱动因素进行了研究,得到以下结论:长江经济带三次产业能源消费起源CO_2排放量约占全国排放总量的三分之一,1995~2012年间CO_2排放总量逐年增加,2013年稍有下降,第二产业是CO_2主要排放源,占三次产业CO_2排放总量的80%左右;1996~2013年,长江经济带CO_2排放与经济发展之间动态关系在大多数年份处于弱脱钩状态,少数年份出现了强脱钩和扩张性负脱钩状态;经济因素是阻碍CO_2排放脱钩的最主要因素,能源强度因素是促进CO_2脱钩的最主要因素,结构因素对CO_2脱钩也起阻碍作用,碳排放系数因素影响不稳定. 相似文献
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Mature Archean continental crust in the Yangtze craton: Evidence from petrology, geochronology and geochemistry 总被引:3,自引:0,他引:3
Previous studies have shown that the Archean basement is widely distributed throughout the Yangtze craton. To date, however, Archean basement terrains have not been found, except for a few Kongling high-grade metamorphic terrains in the Huangling dome that have been confirmed to be of Archean age. To further understand the basement component and crustal evolution of the Yangtze craton, we carried out a petrological, geochronological and geochemical study of the Jinshan K-feldspar granite emplaced within the Yangpo Group, located in Huji Town, Zhongxiang City, Hubei Province. Results indicate that the zircon SHRIMP U-Pb age of the Jinshan granite is 2655±9 Ma, placing it within the middle Neoarchean. Chemically, this pluton yields abundant silica and alkalis and is depleted in Ca, Mg and Ti. Furthermore, it is enriched in Rb, Th, Ga, Y and Zr, depleted in Sr, Ba, Nb and Ta, and especially lacking in Eu. High ratios of FeO*/MgO (32.0 to 58.7) and 104 ×Ga/Al (3.19 to 3.41) were also found. The pluton exhibits characteristics typical of A-type granites with crustal source magmas. Moreover, the meta-sedimentary rock association of the Yangpo Group, into which the pluton intruded, clearly shows relatively stable depositional environments of a shallow shelf sequence. Therefore, before the middle Neoarchean, the Yangtze craton contained mature continental crust. This breakthrough discovery opens a new window on the study of the formation and evolution of the Yangtze craton basement. 相似文献
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《科学通报(英文版)》2008,(Z1):140-152
Environmental archaeology of archaeological sites on both sides of the Dachang section in the Daning River,the Three Gorges of the Yangtze River,shows that riverbed evolution has a great influence on the distribution of archaeological sites during the prehistorical and historical period,and it restricts human activity and the development of ancient culture.Field investigation,dating data,paleocurrent analysis of 100 gravels on the riverbed and archaeological excavation reveal that the riverbed of the Dachang section developed in the Shuangyantang region during the early stage,after about 30 kaBP it shifted westward gradually and reached the present place.Along with the westward shift,the focus of ancient culture changed for several times.In the Western Zhou Dynasty’s period,the east riverbank of the Daning River was the main residential area.During the Han Dynasty,along with the westward shift,the living space of ancient people was no longer confined to the east riverbank and the focus of culture moved westward.Then the Zhangjiawan site became the main dwelling district.In the late Han Dynasty, the villages were flooded and the ancients had to immigrate to a high place.Tombs of the Han and the Jin Dynasties outcropped on the flood plain of the east bank because their surface sediments were eroded by several flood events and the westward shift of the riverbed. 相似文献
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东昆仑构造岩浆带的划分及晚华力西期-燕山期岩石构造组合 总被引:2,自引:0,他引:2
《青海大学学报》2010,(5)
论述东昆仑火成岩与构造演化关系密切,空间上构成明显的分带性。依据印支-燕山期岩浆岩时空组构、岩石构造组合及动力学特征可将东昆仑构造岩浆带自北向南划分为祁漫塔格-都兰、东昆北、东昆南、及东部的鄂拉山四个构造岩浆带,自西向东划分为西、中、东三个区段;结合东昆仑碰撞造山过程的特点,将火成岩构造组合与其他(沉积、变质等)岩石构造组合及其所处动力学背景结合起来,划分火成岩构造组合。 相似文献
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阐述了农业技术进步对经济增长贡献份额的两种主要方法——索洛余值法与指数法。并专将种植业从农业中分离出来,用索洛余值法测算了1995年至2006年上海,浙江和江苏省三地种植业的科技进步贡献率。在分析对比三地生产要素弹性的基础上,发现21世纪后三地种植业科技进步贡献率下降。这显然与整个农林牧渔业领域科技进步贡献率不断上升有悖。因此,认为我国在加快促进林牧渔业技术进步的基础上,也不能忽视了种植业领域的科技进步。 相似文献
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Detrital zircon U-Pb ages of Late Cenozoic sediments from the Yangtze delta: Implication for the evolution of the Yangtze River 总被引:1,自引:0,他引:1
JunTao Jia HongBo Zheng XiangTong Huang FuYuan Wu ShouYe Yang Ke Wang MengYing He 《科学通报(英文版)》2010,55(15):1520-1528
Detrital zircon grains of Late Cenozoic sediments dated back to ca.3.6 Ma from core DY03 in the Yangtze delta were dated by LA-ICP-MS,in order to investigate the sedimentary provenance and to find some clue for the evolution of the Yangtze River.Most of the detrital zircon U-Pb ages are distributed at 100 300 Ma,350 550 Ma,600 1000 Ma,1400 2000 Ma and 2200 2800 Ma,which correspond well with the main tectonic and magmatic events in the Yangtze drainage.The detrital zircon age patterns show distinct differenc... 相似文献
20.
Based on daily observation records of fog and atmospheric visibility from 24 meteorological stations in the Yangtze Delta in the period from 1954 to 2005,the identification standard of dense fog events(DFE)has been proposed in this paper,a quite complete time series of DFEs for the delta constructed,and the climate characteristics of these events analyzed sequentially.Preliminary results showed that there were 564 typical DFEs in the delta from 1954 to 2005.The most frequent season for DFEs was from October to next April,when the number of the events accounted for 89.9% of the annual total,while the least frequent season was summer,when the number only accounted for 1.6% of the total due to higher temperature and more convective weather in the season.In the Yangtze Delta, DFEs occurred less and were weaker in the 1960s,but turned to increase from the end of the 1970s to the beginning of the 1980s,with an abrupt change in 1978.Afterwards,DFEs occurred more frequently,intensively,and indeterministically,and in particular,most fre- quently in the 1980s and intensively in the 1990s.However both the frequency and intensity of DFEs decline apparently in the period of 2000—2005 in the delta. 相似文献