POM对南海海温年变化的模拟   总被引：7，自引：3，他引：4  

钱永甫  王谦谦  朱伯承 《大气科学》2000,24(3):373-380

将Internet上的美国普林斯顿大学海洋模式（POM）改造为能够模拟南海（SCS）海洋要素的模式。在POM中,加入了真实的南海海底地形,使用了误差扣除的压力梯度计算方法,引进了海气界面上热通量计算方案,增加了前置和后置处理程序,使模式能够根据研究目的,模拟和预测海洋要素的时间变化及空间分布。利用改造后的POM模拟了南海海温的年变化,并进行了详细的分析和讨论。结果表明,改造后的POM可较好地模拟出南海海温的年变化特征,其模拟性能随季节而有不同。文中对模拟中存在的不足之处也进行了讨论。  相似文献   

公里级CMA_MESO模式FSS评分技术研究     

刘志丽  Jimy Dudhi  陈静  齐倩倩 《气象科技》2022,50(5):660-669

本文研究计算CMA_MESO模式预报降水FSS（Fractions Skill Score）评分时,当其水平分辨率与观测降水不一致时,采取两种匹配方式统一分辨率,分析这两种方式得到的FSS评分结果是否有差异。针对3 km分辨率CMA_MESO模式6 h累积降水,选取5 km分辨率的观测降水,分别采取预报降水匹配观测降水分辨率,以及观测降水匹配预报降水分辨率两种方式,选择4种邻域尺度：5、25、51和105 km;4种降水阈值：0.1、4、13和25 mm,得到两组不同预报时效的FSS评分。通过分析发现：两组FSS评分结果没有显著差异。研究结果表明,当CMA_MESO模式预报降水水平分辨率与观测降水不一致时,可以将预报降水匹配到观测降水格点场,也可以将观测降水匹配到预报降水格点场,两种匹配方式对FSS评分结果没有影响。  相似文献   

Beach ridges of Dali Lake in Inner Mongolia reveal precipitation variation during the Holocene     

Mengyao Jiang  Zhiyong Han  Xusheng Li  Yong Wang  Thomas Stevens  Jun Cheng  Cunjuan Lv  Yuwen Zhou  Qianqian Yang  Zhiwei Xu  Shuangwen Yi  Huayu Lu 《第四纪科学杂志》2020,35(5):716-725

Variability in East Asian summer monsoon precipitation during the Holocene remains of debate. In this study, we use a closed lake with well-dated lake beach ridges located on the margin of the East Asian summer monsoon, a region highly sensitive to monsoon precipitation changes, to obtain a temporal sequence of water volume in North China. The elevation of each beach ridge calibrated to the modern lake level was surveyed. Optically stimulated luminescence dating of undisturbed sediments of beach ridges was performed. The lake area and water volume corresponding to each beach ridge were calculated using a digital elevation model. This study reveals relatively reduced monsoon precipitation from ~12 to 7 ka interrupted by strengthening of the monsoon circulation to a maximum from ~7 to ~5 ka and followed by greatly reduced monsoon intensity until the present day. These results demonstrate that changes in the East Asian summer monsoon precipitation may not be directly driven by global temperature or atmospheric CO₂ content. Rather, we suggest that variation in the the monsoon margin precipitation is probably mainly driven by ice volume and subordinately by the summer solar insolation difference between mid-latitude land and low-latitude ocean.  相似文献   

螺旋箍筋约束套筒浆锚搭接的装配式剪力墙抗震性能有限元分析          下载免费PDF全文

王倩倩  王丽霖  孙海玲 《地震工程学报》2021,43(6):1429-1435,1451

采用有限元分析软件ABAQUS建立现浇剪力墙和螺旋箍筋约束套筒浆锚搭接装配式剪力墙有限元模型,用单向加载的方法模拟模型的正向骨架曲线。结果表明,在边缘构件受压区设置约束混凝土模型,可以较好地模拟螺旋箍筋约束边缘构件的剪力墙的抗震指标,并证明利用ABAQUS软件模拟现浇和装配式剪力墙力学性能的可行性,为采用浆锚搭接的装配式剪力墙相关的研究提供依据。  相似文献   

Particulate organic carbon export flux by ²³⁴Th/²³⁸U disequilibrium in the continental slope of the East China Sea     

BI Qianqian  DU Jinzhou  WU Ying  ZHOU Jing  ZHANG Jing 《海洋学报(英文版)》2013,32(10):67-73

234Th is widely used to quantify the magnitude of upper ocean particulate organic carbon(POC)export in oceans.In the present work,the rates of particulate organic carbon export were measured based on the distribution patterns of234Th/238U disequilibrium in the water column within the continental slope of the East China Sea(ECS)during May 2011.The profiles of particulate and dissolved234Th activities at all three stations showed a relative deficit with respect to238U in the upper 100 m of the water column.The dissolved234Th scavenging rates and the particulate234Th removal rates and their residence times were calculated by a one-dimensional steady state model.The results showed that the dissolved234Th scavenging rates and the particulate234Th removal rates ranged from 12.4–61.4 dpm/(m3·d)andfrom3.8–21.8 dpm/(m3·d),respectively.The residence times of dissolved and particulate234Th were in the range of 3.4–158 d and 63.7–96.5 d,respectively.Combined with the measurement of POC/234Th ratios of suspended particles,POC export flux(calculated by carbon)from the euphotic zone was estimated in the study region,which ranged from 4.14–14.7 mmol/(m2·d),withanaverageof8.21mmol/(m2·d),occupying35%oftheprimeproductivity in the study area.The results of this study can provide new information for better understanding the carbon biogeochemical cycle within the continental slope of the ECS.  相似文献   

Bayesian methods for outliers detection in GNSS time series   总被引：1，自引：0，他引：1  

Zhang Qianqian  Gui Qingming 《Journal of Geodesy》2013,87(7):609-627

This article is concerned with the problem of detecting outliers in GNSS time series based on Bayesian statistical theory. Firstly, a new model is proposed to simultaneously detect different types of outliers based on the conception of introducing different types of classification variables corresponding to the different types of outliers; the problem of outlier detection is converted into the computation of the corresponding posterior probabilities, and the algorithm for computing the posterior probabilities based on standard Gibbs sampler is designed. Secondly, we analyze the reasons of masking and swamping about detecting patches of additive outliers intensively; an unmasking Bayesian method for detecting additive outlier patches is proposed based on an adaptive Gibbs sampler. Thirdly, the correctness of the theories and methods proposed above is illustrated by simulated data and then by analyzing real GNSS observations, such as cycle slips detection in carrier phase data. Examples illustrate that the Bayesian methods for outliers detection in GNSS time series proposed by this paper are not only capable of detecting isolated outliers but also capable of detecting additive outlier patches. Furthermore, it can be successfully used to process cycle slips in phase data, which solves the problem of small cycle slips.  相似文献   

先存断层产状及其组合关系对反转构造变形影响的离散元数值模拟研究     

孙倩倩  刘志娜  余一欣  唐贤君  陈石  彭浩 《大地构造与成矿学》2022,46(1):22-35

反转构造在我国含油气盆地中广泛发育,对于油气勘探具有重要意义.本文采用离散元颗粒流方法研究了先存正断层的陡缓程度、倾向组合关系和距离挤压端的远近等因素对断层的反转构造发育及其反转量的影响.模拟结果显示,先存断层的产状及其距离挤压端的远近会影响先存断层的反转次序、反转量,进而影响盖层内反转构造的发育.当先存正断层倾向指向...  相似文献   

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高鹏飞  楼益栋  王仲想  尹倩倩 《大地测量与地球动力学》2014,34(3):116-120

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Kinematics and age constraints of deformation in a Late Carboniferous accretionary complex in Western Junggar,NW China     

Ji'en Zhang  Wenjiao Xiao  Chunming Han  Songjian Ao  Chao Yuan  Min Sun  Hongyan Geng  Guochun Zhao  Qianqian Guo  Chong Ma 《Gondwana Research》2011,19(4):958-974

The Karamay area, situated in the eastern part of Western Junggar, Southern Altaids, contains an ophiolitic mélange with ultramafic rocks, gabbro, basalt, chert and limestone, which show typical block-in-matrix structures, and coherent turbidites and tuffs. These lithological associations are interpreted as incoherent and coherent series formed in an accretionary complex. On the basis of detailed field mapping and analyses of the asymmetry of imbricate thrusts, duplexes, tilted structures, shear band cleavages, and the NW-verging inclined to overturned folds, we conclude that the overall movement in the accretionary complex was top-to-the-NW. The youngest tuff involved in the deformation contains detrital zircons that have a U–Pb age (LA-MC ICP-MS) of 308 ± 7 Ma. ³⁹Ar–⁴⁰Ar resistance furnace step-heating of amphibole separates from a diorite dike, which cuts the folded and imbricated rocks in the accretionary prism, yielded a plateau age of 307 ± 2 Ma. Consequently, the age of the deformation in the prism is tightly constrained at 307–308 Ma, implying that the deformation occurred in an extremely short time-span during SE-ward subduction. Combined contemporaneous occurrence of Baogutu adakite, high-Mg, Sr-enriched and Y-poor dioritic dikes, Miaoergou charnockite, and Maliya mafic rocks, we further suggest the accretionary complex was cut by near-trench volcanic rocks and plutons possibly due to interaction with a spreading ridge.  相似文献   

多维距离对流动人口回流意愿的影响及群体异质性     

殷江滨  张倩倩  武文杰  黄晓燕  翟婧彤  祁琪 《地理学报》2022,77(12):3146-3161

人口回流正成为中国人口流动的重要趋势,并将深刻影响中西部及沿海地区的发展前景。本文从地理学的“距离”视角切入,在传统人口迁移理论的基础上,将两个非经济因素的距离维度,即制度距离和文化距离引入人口回流研究,构建了多维距离影响流动人口回流意愿的理论框架,并运用全国层面的流动人口调查数据进行实证分析。结果发现：与理论预测一致,流入地与户籍地间的多维距离对流动人口的回流意愿具有显著的影响。经济距离抑制了流动人口的回流,而地理距离、制度距离和文化距离均对人口回流产生促进作用。在考虑了解释变量可能存在的测量误差后,这一发现依然稳健。此外,多维距离对回流意愿的影响因流动人口个体及所在城市特征的差异而不同。个体异质性方面,随着流动人口年龄的增长和文化水平的提高,经济距离对回流意愿的影响不断增强,而地理距离的影响则逐渐减弱。城市异质性方面,随着城市人口规模的增加,制度距离对回流意愿的促进作用不断减弱;城市经济水平的提高则弱化了地理距离对回流意愿的正向效应。  相似文献