Detecting the relationship between summer rainfall anomalies in eastern china and the SSTA in the global domain with a new significance test method   总被引：1，自引：0，他引：1  

Chuhan Lu  Zhaoyong Guan  Panxing Wang  Mingkeng Duan 《中国海洋大学学报(英文版)》2009,8(1):15-22

It is suggested that the multiple samples in a correlation map or a set of correlation maps should be examined with sig-nificance tests as per the Bernoulli probability, model. Therefore, both the contemporaneous and lag correlations of summertime pre-cipitation R in any one of the three regions of Northern China (NC), the Changjiang-Huaihe River Valley (CHRV), and Southern China (SC) with the SSTA in the global domain have been tested in the present article, using our significance test method and the method proposed by Livezey and Chen (1983) respectively. Our results demonstrate that the contemporaneous correlations of sum-mer R in CHRV with the SSTA are larger than those in NC. Significant correlations of SSTA with CHRV R are found to be in some warm SST regions in the tropics, whereas those of SSTA with NC R, which are opposite in sign as compared to the SSTA-CHRV R correlations, are found to be in some regions where the mean SSTs are low. In comparison with the patterns of the contemporaneous correlations, the 1 to 12 month lag correlations between NC R and SSTA, and those between CHRV summer R and SSTA show simi-lar patterns, including the magnitudes and signs, and the spatial distributions of the coefficients. However, the summer rainfall in SC is not well correlated with the SSTA, no matter how long the lag interval is. The results derived from the observations have set up a relationship frame connecting the precipitation anomalies in NC, CHRV, and SC with the SSTA in the global domain, which is criti-cally useful for our understanding and predicting the climate variabilities in different parts of China Both NC and CHRV summer R are connected with El Nino events, showing a'--'pattern in an El Nino year and a'+ +'pattern in the subsequent year.  相似文献   

基于拔桩能力的自升式平台海外作业优选     

宋林松  曹式敬  李军伟  段梦兰 《海洋地质译丛》2010,(4):106-110

针对某海外项目中可能遇到的钻井平台压载后入泥深度过大和拔桩困难的问题,开展平台优选计算。首先搜集了预定作业井位周围井位的地质勘查资料,利用二次插值法进行作业井位地质勘察数据计算,据此计算了桩脚入泥深度,并根据作业平台结构参数计算了平台的拔桩阻力。为解决平台极限拔桩能力小于拔桩阻力的问题,设计了可控冲桩阀和冲桩系统以消除或减小桩靴底部的吸附力、桩靴侧部土体剪切力和桩靴上部土重。最后将平台拔桩能力与最终拔桩阻力进行对比,给出平台推荐结果。  相似文献   

两形态类型织纹螺(Nassarius)的鉴定   总被引：3，自引：2，他引：1  

李海涛  张敬怀  董燕红  方宏达  林端  李秀芹  欧强 《海洋与湖沼》2008,39(4)

在整理广东珠海高栏岛潮下带的螺类样品时,发现两不同形态类型的织纹螺,一类型鉴定为西格织纹螺（Nassarius siquijorensis）,另一类型与前者在内唇和外唇形态上存在明显差异但其他特征基本相同。比较了两类型个体的齿舌形态,并对选取的5个个体的COⅠ基因序列进行了研究。结果表明,两类型个体的齿舌形态基本一致,齿列数53—66排,中央齿上缘小齿8—12枚;COⅠ基因序列存在较大的变异,709bp的DNA片段上共有40个位点变异,其中38个变异位点为密码子第三位碱基,个体间的碱基差异在2—35bp之间;贝壳变异与DNA变异不存在关系,同类型的个体在DNA序列上差异较大,不同类型个体的差异却极小;在基于COⅠ基因序列构建的系统树中两类型的个体明显聚为一支。依据5条COⅠ基因核苷酸序列推导的氨基酸残基序列完全相同。齿舌形态和分子生物学证据都证实两种类型的个体同属于西格织纹螺。  相似文献   

基于空间密度函数的哈尼梯田世界遗产地滑坡时空格局变化   总被引：2，自引：0，他引：2  

丁智强  高璇  角媛梅  李玉辉  郭汝军 《热带地理》2020,40(3):478-486

为探究哈尼梯田世界文化景观遗产地核心区滑坡灾害时空分布规律，以Google Earth 0.55 m分辨率的2005、2009、2015年3期遥感影像为基础，结合实地走访调查，建立滑坡数据库，在ArcGIS 10.2平台上计算滑坡点的最邻近指数、K函数曲线及密度分布。结果显示：1）哈尼梯田遗产核心区2005、2009、2015年的滑坡数量分别为184、337和285个，对应最邻近指数为0.556、0.603、0.628；最显著聚集的空间尺度为1 000 m，从聚集向离散分布转变的空间尺度阈值分别为2.9、3.9、3.6 km。2）3个年份滑坡点高密度区占比逐渐增加（2.3%→5.8%→8.3%），中密度区占比亦逐渐增大（15.7%→21.8%→27.9%），低密度区占比逐渐减小（82.0%→72.5%→66.8%）。3）需要重点防范滑坡灾害风险的区域为森林区的西段和东段，村寨区的多依树、硐浦、勐品、水卜龙等地，以及阿勐控河和碧猛河流域内的梯田区。综上，研究区2005－2015年滑坡空间格局发生了显著变化，随着人类活动对地表景观干预程度不断加大，滑坡灾害风险增加了更多的不确定性。  相似文献   

塔里木盆地南部中生代碰撞相关构造及其在古特提斯研究中的意义     

李勇  李曰俊  杨宪彰  文磊  黄少英  张亮  王祥  陈才  王斌  段云江  周慧  李洪辉  刘亚雷  黄彤飞 《地质科学》2022,57(2):315-340

地震资料解释和野外地质调查,在塔里木盆地南部发现中生代碰撞相关构造.同碰撞构造发育于西昆仑山前、阿尔金山前和麦盖提斜坡,为晚三叠世冲断构造.既有晚三叠世新形成的冲断构造,也有先存构造的复活(如车尔臣断裂).碰撞后构造见于西昆仑和阿尔金山前,是一些规模不大的侏罗纪—白垩纪正断层及其控制下形成堑—垒构造.晚三叠世构造应力场...  相似文献   

The effect of three-dimensional variational data assimilation of QuikSCAT data on the numerical simulation of typhoon track and intensity   总被引：4，自引：0，他引：4  

ZENG Zhihu  DUAN Yihong  LIANG Xudong  MA Leiming  Johnny Chung-leung CHAN 《大气科学进展》2005,22(4):534-544

In this paper, the three-dimensional variational data assimilation scheme (3DVAR) in the mesoscalemod el version 5 (MM5) of the US Pennsylvania State University/National Center for Atmospheric Research is used to study the effect of assimilating the sea-wind data from QuikSCAT on the prediction of typhoon track and intensity. The case of Typhoon Dujuan (2003) is first tested and the results show appreciable improvements. Twelve other cases in 2003 are then evaluated. The assimilation of the QuikSCAT data produces significant impacts on the structure of Dujuan in terms of the horizontal and vertical winds, sealevel pressure and temperature at the initial time. With the assimilation, the 24-h (48-h) track prediction of 11 (10) out of the 12 typhoons is improved. The 24-h (48-h) prediction of typhoon intensity is also improved in 10 (9) of the 12 cases. These experiments therefore demonstrate that assimilation of the QuikSCAT sea-wind data can increase the accuracy of typhoon track and intensity predictions through modification of the initial fields associated with the typhoon.  相似文献   

Chemical characteristics of haze during summer and winter in Guangzhou   总被引：33，自引：0，他引：33  

Ji-Hua Tan  Jing-Chun Duan  Duo-Hong Chen  Xin-Hua Wang  Song-Jun Guo  Xin-Hui Bi  Guo-Ying Sheng  Ke-Bin He  Jia-Mo Fu 《Atmospheric Research》2009,94(2):238-245

Airborne particles were collected with a 10-stage MOUDI and a PM₁₀ sampler in Guangzhou, China, during both haze and normal days in the summer of 2002 and 2003, and winter 2002. The characteristics of PAHs, organic carbon, elemental carbon and water-soluble inorganic ions were studied under four periods (summer normal, summer haze, winter normal and winter haze). In this study, secondary pollutants (OC, SO₄²⁻, NO₃⁻ and NH₄⁺) were the major chemical components and appeared to show a remarkably rapid increase from normal to haze days. The particle mass size distributions were bimodal and dominated by fine particles in haze days. A significantly higher OC/EC ratio was found in haze days (3.2–4.7) compared to normal days (1.8–2.8), indicating secondary organic aerosol formation might be significant during haze days. Correlation analysis between visibility and chemical species showed that the major scattering species were TC (total carbon) and sulfate in normal days and nitrate and TC in haze days, respectively. Simultaneously, correlation analysis between visibility and meteorological factors demonstrated that visibility increased with both temperature and wind speed, while it decreased with relative humidity. Furthermore, the relatively higher value of IcdP/(BghiP + IcdP) and the low value of Cmax, CPI, and BghiP/BeP in winter haze could be due to the growth of motor vehicle usage and energy consumption in winter.  相似文献   

用SA雷达产品对京西三次局地暴雨落区形成的精细分析   总被引：6，自引：3，他引：3  

段丽  卞素芬  俞小鼎  崔永义 《气象》2009,35(3):21-28

利用新一代Doppler雷达各种探测产品,对2006年6月底至7月上旬北京西郊香山、石景山、门头沟一带落区相同的三次局地暴雨和大暴雨过程,进行精细分析和研究.重点分析雷达探测产品对落区在同一地点形成的短时临近影响系统和指示意义.研究表明,发生在北京西郊山前、落区相同的三次局地暴雨和大暴雨,其雷达回波发展和演变形式各不相同.但三次过程强降雨前,近地面平原东南风和边界层偏西风的垂直风廓线结构在地形作用下对暴雨落区形成的影响是一致的:近乎与山脉垂直的平原近地面东南风长时间(6小时左右)维持,增加山前局地近地面温湿条件,并在北京西郊山脉阻挡下,形成山前近地面局地辐合和强迫抬升.山顶附近边界层的偏西风为近地面空气强迫抬升后在边界层的后卷辐散提供了有利条件.研究还显示,落区附近单体风暴、逆风区辐合带、中气旋等中小尺度回波系统的活动和发展,是暴雨落区形成的重要因素.  相似文献   

沪宁高速公路大雾及气象要素特征分析   总被引：3，自引：0，他引：3  

吴和红  严明良  缪启龙  段春锋 《气象与减灾研究》2010,33(4):31-37

利用2006年6月-2009年5月沪宁高速公路AWM自动气象站资料,研究了不同类型大雾持续时间、能见度变化及其出现过程中风、湿度变化特征。结果表明,有超过50%的大雾会发展成浓雾;大雾持续时间以平流雾最长,辐射雾最短;67.6%的大雾在长时间低能见度之前会出现类似"象鼻"形的突变前兆,这可能与地理环境有关;大雾过程中风向以东风和西风为主,锋面雾有部分为偏南风;平流雾发生时风速较辐射雾和锋面雾大,锋面雾发生时风速较多为静风,结束时风速快速增大;平流雾发生时相对湿度多有突变,而辐射雾、锋面雾的相对湿度以渐变为主。  相似文献   

塔里木多旋回盆地复合构造样式初步分析   总被引：20，自引：10，他引：10  

何治亮  徐宏节  段铁军 《地质科学》2005,40(2):153-166

塔里木盆地多旋回的演化历史导致了多期次的复合构造变形作用。不同方式的构造运动导致了不同方式的复合,不同等级和不同规模的变形叠加导致了不同级次的复合构造。根据造成复合构造的应力场变化的特征,结合具体实例将塔里木盆地复合构造划分为8种主要类型:继承性挤压、继承性走滑、挤压--走滑、走滑--挤压、拉张--挤压、挤压--拉张、挤压--重力和重力--挤压复合构造。复合构造为油气运移提供了新的运移动力场及高效输导体系。构造复合一方面可能会加大早期构造的幅度并使其更为复杂,另一方面会导致各种圈闭更为复杂的平面组合与纵向叠置方式。构造复合对早期已聚集的油气存在一定的破坏作用,同时,由多油源、多期生烃、多通道、多圈闭类型和多成藏期组成的成藏条件也在复合构造中形成了以塔河--轮南特大型油气田为代表的复式油气聚集带。  相似文献