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151.
近惯性内波广泛存在于全球海洋,是维持深层海洋跨等密度面湍流混合及海洋层结的重要能量来源。基于黑潮-亲潮混合区的多年深海潜标数据,分析了:(1)该海域近惯性内波及其能量的季节变化特征与影响因素,(2)上层和深层近惯性运动的频率、波数谱及垂向分布等特征。结果表明,该海域存在丰富的近惯性动能,无论海洋上层还是深层均呈现显著的冬季强、夏季弱的季节变化特征,冬季(12~2月)上层的近惯性能量可占全年能量的41%,深层近惯性信号同样显著,同潮汐信号相当。平板模型分析表明,该区域近惯性动能的季节循环特征主要受风场的季节变化所主导,同时受到黑潮延伸体流轴的摆动调制。 相似文献
152.
Aleksi Räsänen Vera Kauppinen Sirkku Juhola Gunhild Setten Haakon Lein 《Norsk geografisk tidsskrift. Norwegian journal of geography》2020,74(3):165-180
ABSTRACT Despite a notable increase in the literature on community resilience, the notion of ‘community’ remains underproblematised. This is evident within flood risk management (FRM) literature, in which the understanding and roles of communities may be acknowledged but seldom discussed in any detail. The purpose of the article is to demonstrate how community networks are configured by different actors, whose roles and responsibilities span spatial scales within the context of FRM. Accordingly, the authors analyse findings from semi-structured interviews, policy documents, and household surveys from two flood prone areas in Finnish Lapland. The analysis reveals that the ways in which authorities, civil society, and informal actors take on multiple roles are intertwined and form different types of networks. By implication, the configuration of community is fuzzy, elusive and situated, and not confined to a fixed spatiality. The authors discuss the implications of the complex nature of community for FRM specifically, and for community resilience more broadly. They conclude that an analysis of different actors across scales contributes to an understanding of the configuration of community, including community resilience, and how the meaning of community takes shape according to the differing aims of FRM in combination with differing geographical settings. 相似文献
153.
杨俊梅 《沙漠与绿洲气象(新疆气象)》2023,17(6)
基于2011年5月9日山西中部地区一次积层混合云降水的机载探测和地面雨滴谱观测资料,分析了空中云系微物理参量的垂直分布、冰晶形态及演变和地面降水的微物理特征。结果表明:此次积层混合云为冷云结构,垂直分布不均匀,云中过冷水较为丰沛,对流泡的存在造成云内不同区域云水含量不均匀。云滴的凝华增长导致5.3 km处大云粒子和降水粒子数浓度明显增加。小云粒子谱分布以单峰型为主,峰值直径主要位于5~6 μm或9~10 μm,大云粒子谱分布呈多峰型,不同高度处变化较大。此次降水观测到的冰晶形态包括板状、针柱状、柱帽状、辐枝状和不规则形状,4.9 km处受聚合和淞附过程的共同影响,辐枝状和针柱状冰晶增多,在4.1 km处融化层附近淞附状冰晶明显增加。地面降水受到雨滴谱仪布设位置的影响,其微物理结构主要呈现为层状云降水的特征。 相似文献
154.
Precipitation episodes in the form of freezing rain and ice pellets represent natural hazards affecting eastern Canada during the cold season. These types of precipitation mainly occur in the St. Lawrence River valley and the Atlantic provinces of Canada. This study aims to evaluate the ability of the fifth-generation Canadian Regional Climate Model (CRCM5), using a 0.11° horizontal grid mesh, to hindcast mixed precipitation when driven by reanalyses produced by the European Centre for Medium-range Weather Forecasts (ERA-Interim) for a 35-year period. In general, the CRCM5 simulation slightly overestimates the occurrence of freezing rain, but the geographical distribution is well reproduced. The duration of freezing rain events and accompanying surface winds in the Montréal region are reproduced by CRCM5. A case study is performed for an especially catastrophic freezing-rain event in January 1998; the model succeeds in simulating the intensity and duration of the episode, as well as the propitious meteorological environment. Overall, the model is also able to reproduce the climatology and a specific event of freezing rain and ice pellets. 相似文献
155.
XIAO Chuantao Jianghan Petroleum Institute Jingzhou Hubei PAN Yuntang Graduate School Academia Sini Beijing Liu Xinzhu 《《地质学报》英文版》1999,73(3):341-347
The Carboniferous system in the Xiaohaizi area, Bachu County, Xinjiang Uygur Autonomous Region, composed of typical mixed terrigenous clastic, carbonate and sulphate sediments, was mainly deposited in the tidal flat and lagoon environments. The mixed sediments occur as the following eleven types: 1. limestone intercalated with siltstone; 2. interbeds of shale and limestone; 3. gypsolyte interbedded with limestone; 4. gypsolyte intercalated with siltstone; 5. gypsolyte interbedded with shale; 6. gypsolyte intercalated with siltstone, limestone and dolomite; 7. siltstone interbedded with gypsolyte and limestone; 8. terrigenous detritus scattered in carbonate matrix; 9. carbonate as cement in clastic rocks; 10. mixed sediments of carbonate and terrigenous mud; 11. mixed sediments of carbonate grains with terrigenous sand. Based on the analysis of the dynamic mechanism of mixed sediments, it is believed that these types of mixed sediments in the study area were controlled by climate, sea level change and so 相似文献
156.
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158.
提出了有着广泛应用的混合线性模型中参数估计的一种新方法,称层三角变换估计。将该变换用于检验和估计中,将产生一束套用于全面分析混合线模型的计算过程,这些过程在计算是稳定的,而且节省空间。 相似文献
159.
钢屈服—摩擦复合耗能器的性能研究 总被引:6,自引:1,他引:5
本文提出了“综合利用不同耗能原理和机制来设计新型耗能器”的思想,研究开发了钢屈服-摩擦复合耗能器,并对其进行了性能试验和对比试验,考察了耗能器的工作性能和耗能性能。给出了耗能器的恢复力模型,研究结果表明,钢屈服-摩擦复合耗能器利用钢屈服滞回和摩擦两种机制耗能,具有稳定的工作性能,耗能能力强且可调节,构造简单,形状紧凑,体积小,造价低,制作与安装方便,是一种有广阔应用前景的新型耗能减震装置。 相似文献
160.
Parameterized thermal model of a mixed mantle convection 总被引:4,自引:0,他引:4
IntroductionTectonicevolutionisinfluencedbythermalhistoryoftheEarth.TheEarthhasabout4.6Gahistory.ThermalenergyfromtheinterioroftheEachprovidesthemainpowerfortectonicevolution.ItnotonlycontrolstheformationofthelayeredstructuresinsidetheEarth,butalsopromotesthetectonicmovementsofthesurfaceplatesduringthegeologicalera.ThestudyofthethermalhistoryoftheEarthhaspassedseveralstages.Inearlystudies,onlyconductivemechanism(Lubimova,1958)isdiscussedinthethermalevolution.However,theimpotalceofthermalco… 相似文献