东南沿海前汛期与后汛期降水的比较分析   总被引：4，自引：1，他引：3  

任广成  范飞龙  沈爱华 《海洋预报》2007,24(1):16-24

本文通过对东南沿海前汛期降水与后汛期降水的多年气候变化及500hPa环流场和北太平洋海温场对比分析发现:前汛期降水与后汛期降水在年代际变化上差异明显。前汛期降水逐年变化幅度小,大旱、大涝年少;后汛期降水逐年变化幅度大,大旱、大涝年多。前汛期降水与后汛期降水的大旱、大涝年环流形势场和海温场均存在明显差异。在与北半球500hPa高度场和北太平洋海温场的相关分布上,表现出基本相反的分布类型。计算分析还发现,前期8～9月和冬季1～2月北半球副高,尤其是太平洋副高与前汛期降水相关尚好。前期1月赤道洋流区中部海域的海温,对前汛期降水均有较好的预测指示意义。前期2月北大西洋涛动和黑潮区以东至太平洋中部海域的海温对后汛期降水具有较好的预测指示意义。  相似文献   

冬季西太平洋副高异常变化对我国气温的影响及其与前期北太平洋海温的关系   总被引：1，自引：1，他引：0  

任广成  吴小林  沈爱华 《气象与环境科学》2007,30(3):10-13

利用1951-2005年全国160个站气温资料、西太平洋副高特征指数和北太平洋海温资料,分析了冬季西太平洋副高强度和位置异常变化对我国气温的影响及其与前期北太平洋海温的关系,结果发现:冬季西太平洋副高强度和西伸脊点与我国气温分别存在着很好的正、负相关关系;前期北太平洋海温距平场呈现厄尔尼诺和拉尼娜分布型及赤道东太平洋海温异常变化,对冬季西太平洋副高强度和位置具有很好的预测指示意义.  相似文献   

Fuzzy risk analysis of dam overtopping from snowmelt floods in the nonstationarity case of the Manas River catchment,China     

Yang  Kuan  Chen  Fulong  He  Chaofei  Zhang  Zhijun  Long  Aihua 《Natural Hazards》2020,104(1):27-49

Natural Hazards - With the significant climate change that has occurred in the Manas River catchment, the temporal and spatial patterns of the natural changes in the regional water cycle have...  相似文献   

Pulse phase-resolved analysis of SMC X-3 during its 2016–2017 super-Eddington outburst     

Hai-Hui Zhao  Shan-Shan Weng  Ming-Yu Ge  Wei-Hao Bian  Qi-Rong Yuan 《Astrophysics and Space Science》2018,363(2):21

The Be X-ray pulsar SMC X-3 underwent an extra long and ultraluminous giant outburst from 2016 August to 2017 March. The peak X-ray luminosity is up to \(\sim10^{39}~\mbox{erg/s}\), suggesting a mildly super-Eddington accretion onto the strongly magnetized neutron star. It therefore bridges the gap between the Galactic Be/X-ray binaries (\(L_{\mathrm{X}}^{\mathrm{peak}} \leq10^{38}~\mbox{erg/s}\)) and the ultraluminous X-ray pulsars (\(L_{\mathrm{X}}^{\mathrm{peak}} \geq10^{40}~\mbox{erg/s}\)) found in nearby galaxies. A number of observations were carried out to observe the outburst. In this paper, we perform a comprehensive phase-resolved analysis on the high quality data obtained with the Nustar and XMM-Newton, which were observed at a high and intermediate luminosity levels. In order to get a better understanding on the evolution of the whole extreme burst, we take the Swift results at the low luminosity state into account as well. At the early stage of outburst, the source shows a double-peak pulse profile, the second main peak approaches the first one and merges into the single peak at the low luminosity. The second main peak vanishes beyond 20 keV, and its radiation becomes much softer than that of the first main peak. The line widths of fluorescent iron line vary dramatically with phases, indicating a complicated geometry of accretion flows. In contrast to the case at low luminosity, the pulse fraction increases with the photon energy. The significant small pulse fraction detected below 1 keV can be interpreted as the existence of an additional thermal component located at far away from the central neutron star.  相似文献   

A three-point method for estimating wave reflection of obliquely incident waves over a sloping bottom     

Swun-Kwang Wang  Tai-Wen Hsu  Wen-Kai Weng  Shan-Hwei Ou 《Coastal Engineering》2008

A three-point method for estimating wave reflection is proposed to account for monochromatic oblique incident waves propagating over a sloping beach. The amplitudes of reflected wave and incident wave are separated using wave amplitudes measured at three fixed wave gauges with a distance. The applicability of the theory is verified by comparing the simulated results with the available theoretical, numerical and experimental results for the estimation of wave reflection. The sensitivity is also tested to provide a more accurate prediction of the reflection coefficient.  相似文献   

单晶固体中正电子波函数的计算     

熊涛  张杰  陈祥磊  叶邦角  杜淮江  翁惠民 《海洋学报》2010,32(10):7374-7377

介绍了正电子波函数计算的两种基本方法——有限差分方法(FDM)与平面波方法(PW).并以单晶Si为例,计算出正电子的波函数,从而计算出正电子在Si中的密度分布;由该正电子密度,进一步计算出了正电子在Si中的体寿命.计算结果与我们最近的实验结果(220 ps)符合得很好.最后,探讨了这两种方法各自的优缺点.  相似文献   

Cambrian integrative stratigraphy and timescale of China   总被引：1，自引：0，他引：1  

Zhu  Maoyan  Yang  Aihua  Yuan  Jingliang  Li  Guoxiang  Zhang  Junming  Zhao  Fangchen  Ahn  Soo-Yeun  Miao  Lanyun 《中国科学:地球科学(英文版)》2019,62(1):25-60

The Cambrian Period is the first period of the Phanerozoic Eon and witnessed the explosive appearance of the metazoans, representing the beginning of the modern earth-life system characterized by animals in contrary to the Precambrian earth-life system dominated by microbial life. However, understanding Cambrian earth-life system evolution is hampered by regional and global stratigraphic correlations due to an incomplete chronostratigraphy and consequent absence of a highresolution timescale. Here we briefly review the historical narrative of the present international chronostratigraphic framework of the Cambrian System and summarize recent advances and problems of the undefined Cambrian stage GSSPs, in particular we challenge the global correlation of the GSSP for the Cambrian base, in addition to Cambrian chemostratigraphy and geochronology. Based on the recent advances of the international Cambrian chronostratigraphy, revisions to the Cambrian chronostratigraphy of China, which are largely based on the stratigraphic record of South China, are suggested, and the Xiaotanian Stage is newly proposed for the Cambrian Stage 2 of China. We further summarize the integrative stratigraphy of South China, North China and Tarim platforms respectively with an emphasis on the facies variations of the Precambrian-Cambrian boundary successions and problems for identification of the Cambrian base in the different facies and areas of China. Moreover, we discuss stratigraphic complications that are introduced by poorly fossiliferous dolomite successions in the upper Cambrian System which are widespread in South China, North China and Tarim platforms.  相似文献   

利用CAP方法分析吉林松原4.9级地震震源机制     

刘爱华  张伟  龚飞  姜锦华  张雁翔  李俊秋  相传芳 《地震地磁观测与研究》2018,39(6):78-85

地震震源机制解的确定,对于地震研究及孕震机理解释具有重要意义。近年来我国东北几次破坏性地震主要发生在吉林松原地区,分析震源机制,对认识该地区地质构造和孕震机理具有重要的科学价值。2017年7月23日吉林松原发生4.9级地震,利用CAP方法,反演得到此次地震震源机制解：节面Ⅰ：走向307.0°,倾角66.0°,滑动角12.0°;节面Ⅱ：走向212.1°,倾角79.1°,滑动角155.5°;震源深度6.9 km,结果表明此次地震震源机制解类型为走滑型。  相似文献   

Effects of the Land Use and Check Dams on Flood in Upper Catchment of Fuping Hydrological Station by Hydrological Modeling     

Fulong Chen  Jintao Zheng  Shaofei Li  Aihua Long 《Water Resources》2018,45(4):508-522

Flood peaks and volumes had been detected a downward trend in Fuping hydrological station. To quantify the effects of check dams on flood peaks and volumes, a hydrological model integrating land use was established. The model performed well in flood processes simulation, and the Nash efficiency of the model was 0.72. Then the model was used to identify the comprehensive effects of land use and land cover change on flood processes by comparing the simulation results of the selected flood events under 1980 and 2000 land use and land cover conditions. 24.5, 37.7 and 51.3% decrease in flood peaks for flood events of greater than 10 years, 5~10 years and less than 5 years return periods, respectively, and 16.3, 27.9 and 28.5% decrease in flood volumes for the three groups flood events of different return periods. Contributions of land use change and check dams to decrease in flood peak and volume were simulated, and it was found that peak discharge and volume for each flood event responded differently to the two factors. The results in this study can provide valuable information on design flood calculation in the basin under land use and land cover change.  相似文献   

Three-dimensional electrical exploration methods for the mapping of polymetallic targets in Gansu Province,China     

Shengping Gong  Yabin Yang  Pinrong Lin  Wenli Wu  Caijun Zheng  Fusheng Shi  Xiaoping Wu  Aihua Weng  Guangzhi Zhang  Guanwen Gu  Yixin Ye 《Geophysical Prospecting》2019,67(7):1929-1947

We describe a three-dimensional electrical exploration system, and its use in carrying out a three-dimensional survey on a polymetallic deposit located in China's Gansu Province. A time-domain-induced polarization method, along with a controlled-source audiomagnetotelluric method, was used to survey the same station points for comparison. Then, a three-dimensional inversion based on the incomplete Gauss–Newton method (for time-domain-induced polarization) and a nonlinear conjugate gradient (for controlled-source audiomagnetotelluric) method were developed and applied in order to model the data sets. Four subsurface targets were mapped by the three-dimensional electrical exploration method. A strong correlation was found between the zones of the revealed ore-bearing anomalies and the geological setting. Using the results of the three-dimensional electrical exploration, we revealed the spatial distribution of the ore-bearing stratum, as well as the relationship between the ore bodies and the stratum. The results potentially provided evidence for future interpretations of deep geological structures, along with evaluations of mineral resources.  相似文献