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621.
Yan  Jin  Tao  Ai-feng  Lin  Yi-nan  Pei  Ye  Liu  Ya-yi  Su  Jun-wei 《中国海洋工程》2020,34(2):210-222
The characteristics of swells within the East China Sea have been reported by Tao et al.(2017), while the question of where the swells come from remains unanswered. By using the wave model WAVEWATCH III and the swell tracking method proposed by Hanson(2001), the spatial sources of the swells are investigated during four typical typhoon scenarios, which usually affect the wave environment in the East China Sea, including the Recurving type,the Northward type, the Westward type(striking the East China Sea) and the Westward type(over the South China Sea). The numerical results show that parts of the swells are from the North West Pacific with a long-distance travelling. The moving paths of the swells are affected by the typhoon tracks, which result in various fetches. The Westward type(over the South China Sea) makes one peak in the evolution process. The landing process of the Westward type(striking the East China Sea) could result in swells with low energy. The swell energy depends on swell propagation distance, existence time and wind intensity of generation fetch. The consistent fetch and forceful wind intensity make swell carry more energy.  相似文献   
622.
作者鉴定中国科学院海洋研究所“金星”号调查船于1975及1976年在东海大陆架区进行综合海洋调查所采的底栖生物标本时,发现近丽海葵属(Paracalliactis)的一个新种一一中华近丽海葵(Paracalliactis sinica sp. nov,)。新种的模式标本保存于中国科学院海洋研究所(青岛)。  相似文献   
623.
提出用氧瓶燃烧-光度法来测定有机物中硫含量的定量分析方法,在低硫酸根浓度范围内(4~25mg/l),在浓碱条件下MTB(甲基百里酚蓝)的吸光度与硫酸根浓度在460nm波长处呈正相关,而在600nm(或610nm)处Ba-MTB络合物的吸光度与硫酸根浓度呈负相关。该方法标准偏差低于0.5mg,/l.变异系数低于3%,回收率为95-107%。  相似文献   
624.
立足于农村宅基地制度改革,以泸县试点为例,对农村宅基地改革试点管理平台建设思路和建设应用进行论述.在平台的构建过程中,充分结合了泸县农村宅基地改革成果,制定了相关数据标准,建立了宅基地改革数据成果入库、日常审批、管理应用、数据更新维护和信息共享等一体化的宅基地管理平台,实现了与国土资源"一张图"有序的衔接与应用.  相似文献   
625.
裴亮  刘阳  陈晨 《地理科学》2017,37(9):1403-1410
基于Landsat遥感影像提取大凌河流域1986~2014年7期土地利用/覆被变化信息,并结合1986~2014年流域气候变化情况,发现大凌河流域土地利用变化对流域气候变化具有负面影响。研究表明: 近30 a大凌河流域土地利用/覆被变化情况表现为:建设用地和农林用地的大幅度扩张,面积分别增加了322.30 km2和1 504.94 km2,并伴随着水域和旱地及其他未利用地面积的显著减少,面积分别减少了102.42 km2和1 724.61 km2; 大凌河流域近30 a来土地利用变化导致流域平均年降水量、平均相对湿度及平均风速小幅度下降,分别减少了14.94 mm、0.2%和0.04 m/s,平均气温缓慢上升,增长了0.1℃; 退耕还林还草及成立凌河保护区等工作能提高流域植被覆盖面积、使流域水域面积得以回升,从而可以缓解城市热岛效应带来的温度升高,提高流域生态环境质量。  相似文献   
626.
鲈鱼群体生化遗传学研究Ⅱ.种群生化遗传结构及变异   总被引:3,自引:6,他引:3  
1995年6月—1996年5月分别在汕头及青岛收集共100尾鲈鱼生化样品,采用淀粉胶及聚丙烯酰胺凝胶电泳分析了鲈鱼17种同工酶,记录出31个基因座位,统计了基因频率。结果表明,2群体间遗传相似度和遗传距离分别为0.9920和0.0080。作者初步认为中国近海鲈鱼为1个种,分南、北2个种群。汕头种群多态座位比例为22.6%,青岛种群为25.8%。x2检验表明,2个群体多态座位等位基因频率除汕头的Est-4外均符合Hardy-Weinberg平衡。汕头与青岛种群平均杂合度分别为0.079和0.099,表明目前鲈鱼种质资源状况尚好,但当前捕捞鲈鱼苗的压力过大,应严格控制鲈鱼苗的捕捞,以免因滥捕仔稚幼鱼而导致资源衰竭。  相似文献   
627.
美丽海葵属三新种   总被引:2,自引:0,他引:2  
美丽海葵属(Calliactis)属链索海葵科( Hormathiidae),有发达的基部,体壁光滑,壁孔1-3环,呈规则状排列于近基部处。柱体外胚层裸露,有时有一薄层分泌的表皮。括约肌很发达,位于中胶层。有2个水管,6对不育的完全隔膜,其收缩肌呈弥散型。海葵体与寄居蟹共栖。本文所用标本分别于1975-1976年采自东海和南海,经鉴定其中有3新种,分述如下。  相似文献   
628.
According to the results of The Second Comprehensive Scientific Expedition on the Qinghai-Tibet Plateau, the balance of solid and liquid water on the Qinghai-Tibet Plateau is disturbed, and a large amount of solid water, such as glaciers and perpetual snow, is transformed into liquid water, which aggravates the risk of flood disasters in the Plateau. Based on the historical flood disaster records of the Qinghai-Tibet Plateau, this paper analyzed the temporal and spatial distribution characteristics of the flood disasters in the Plateau, and estimated the critical rainfall for the flood disasters combined with precipitation data from the meteorological stations in each basin of the Qinghai-Tibet Plateau. The results show that most of the flood disaster events in the Plateau are caused by precipitation, and the average annual occurrence of flood disasters is more than 30 cases and their frequency is on the rise. The high frequency areas of flood disasters in the Qinghai-Tibet Plateau are mainly in the Hehuang Valley and the Hengduan Mountains area; the secondary high frequency areas are located in the valley area of South Tibet and the peripheral area of the Hehuang valley. Finally, we found that the highest critical rainfall value of flood disasters in the Qinghai-Tibet Plateau is in the southern area of the plateau, followed by the eastern and southeastern parts of the plateau, and the lowest values are in the central, western and northern parts of the Plateau.  相似文献   
629.
Recently, the desiccation effect of the North Atlantic Oscillation(NAO) is found to be positively correlated with violent conflict in pre-industrial Europe, with agricultural shrinkage and its subsequent economic shocks to be their causal link. However, it remains unexplored whether the correlation persists if the study period is extended backward in time, a different definition of violent conflict is applied, or the relationship is examined at lower geographic levels. In this study, we based on 835 internal disturbance incidents in Europe during 1049–1800 to conduct long-temporal and multi-scalar examination on the NAO-conflict nexus. ′Time-series′ and ′panel data′ disaggregation approaches, together with Granger Causality, Multiple Regression, and Survival Analyses were applied to verify the nexus quantitatively. Results show that the positive NAO-conflict correlation was significant at the continent and physiographic zone levels. During the positive NAO phases, the annual probability of internal disturbance outbreak increased by 70.0% in the southern Europe and the Mediterranean, a zone most affected by the NAO-induced desiccation effect. Yet, the NAO-conflict correlation was rather inconsistent when it was downscaled to the sub-regional level. Moreover, the NAO-conflict correlation was inflated under the time-series approach, while the panel data approach demonstrated the region-specific nature of the NAO forcing more clearly. The associated implications in examining climate-conflict nexus are discussed. Our findings may be crucial in examining violent conflict in the northwestern Africa, a highly agricultural region affected by the NAO.  相似文献   
630.
Sedimentary sequences with drastic thickening over short distances have been observed in Qiaojia County, Yunnan Province, Southwest China. These are related to a pull-apart basin controlled by the Xiaojiang strike-slip fault. Our field investigations include determining the surface characteristics of the Qiaojia basin which consists of three terrace sequences and a series of alluvial fans. Several drill holes were used to reveal the internal structure of the basin. The results suggest that the basinal sediments are over 300 m thick. From bottom to top, they can be classified into five different units. We inferred that the units of lacustrine sediments are deposited in a paleo-lake which was formed by a paleo-landslide. Accelerator mass spectrometry radiocarbon dating (AMS 14C dating) was used to estimate the ages of the terrace and lacustrine sediments. We use the results to infer that the paleo-lake has existed about 15,000 years and that the Qiaojia basin was uplifted at an average rate of 3.3 mm/a. Furthermore, we then model the evolution process of the basin and interpreted 6 phases of development.  相似文献   
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