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51.
Using the 28°C isotherm to define the Western Pacific Warm Pool(WPWP), this study analyzes the seasonal variability of the WPWP thermohaline structure on the basis of the monthly-averaged sea temperature and salinity data from 1950 to 2011, and the dynamic and thermodynamic mechanisms based on the monthly-averaged wind,precipitation, net heat fluxes and current velocity data. A DT=–0.4°C is more suitable than other temperature criterion for determining the mixed layer(ML) and barrier layer(BL) over the WPWP using monthly-averaged temperature and salinity data. The WPWP has a particular thermohaline structure and can be vertically divided into three layers, i.e., the ML, BL, and deep layer(DL). The BL thickness(BLT) is the thickest, while the ML thickness(MLT) is the thinnest. The MLT has a similar seasonal variation to the DL thickness(DLT) and BLT.They are all thicker in spring and fall but thinner in summer. The temperatures of the ML and BL are both higher in spring and autumn but lower in winter and summer with an annual amplitude of 0.15°C, while the temperature of the DL is higher in May and lower in August. The averaged salinities at these three layers are all higher in March but lower in September, with annual ranges of 0.41–0.45. Zonal currents, i.e., the South Equatorial Current(SEC)and North Equatorial Counter Current(NECC), and winds may be the main dynamic factors driving the seasonal variability in the WPWP thermohaline structure, while precipitation and net heat fluxes are both important thermodynamic factors. Higher(lower) winds cause both the MLT and BLT to thicken(thin), a stronger(weaker)NECC induces MLT, BLT, and DLT to thin(thicken), and a stronger(weaker) SEC causes both the MLT and BLT to thicken(thin) and the DLT to thin(thicken). An increase(decrease) in the net heat fluxes causes the MLT and BLT to thicken(thin) but the DLT to thin(thicken), while a stronger(weaker) precipitation favors thinner(thicker)MLT but thicker(thinner) BLT and DLT. In addition, a stronger(weaker) NECC and SEC cause the temperature of the three layers to decrease(increase), while the seasonal variability in salinity at the ML, BL, and DL might be controlled by the subtropical cell(STC).  相似文献   
52.
针对以离散余弦变换为核心的人类视觉模型舰船检测算法受数据类型限制的问题(即对复数类型的数据检测效果不好),该文提出了一种改进的人类视觉模型SAR图像舰船检测算法。该算法是以快速傅里叶变换代替离散余弦变换,将SAR图像从空间域变换到频率域;快速傅里叶变换对数据类型要求较低,只要求数据是离散的,并且运行效率更高。然后,采用3种星载SAR数据——ENVISAT ASAR(25m)、Sentinel-1(10m)和Cosmo-Skymed(2.5m)进行对比实验。结果表明,以快速傅里叶变换为核心的人类视觉模型舰船检测算法的检测性能和效率优于以离散余弦变换为核心的算法、双参数恒虚警率(CFAR)算法和K分布恒虚警率算法。  相似文献   
53.
基于无人机原始航片数据量大、网络传输速度慢的问题,本文开发了原始航片压缩工具,实现了保留原始分辨率及纹理特征的压缩算法,并成功应用于“四川长宁6.0级地震”“8·20汶川强降雨特大山洪泥石流灾害”等应急测绘任务中,为数据传输、后方处理提供了技术支撑。  相似文献   
54.
Urban areas and its evolution are important anthropogenic indicators and human ecological footprints, and play decisive roles in environmental change analysis, global geo-conditional monitoring, and sustainable development. China has the highest rate of urban expansion and has emerged as an urban expansion hotspot worldwide. In this paper, the progress of studies on Chinese urban expansion based on remote sensing technology are summarized and analyzed from the aspects of urban area definition, remotely sensed imagery applied in urban expansion, monitoring methods of urban expansion, and urban expansion applications. Existing issues and future directions of Chinese urban expansion are discussed and proposed. Results indicate that: 1) The fusion of multi-source remotely sensed imagery is imperative to meet the needs of urban expansion with various monitoring terms and frequencies on different scales and dimensions. 2) To guarantee the classification accuracy and efficiency and describe urban expansion and its influences on local land use simultaneously, the combination of visual interpretation and automatic classification is the tendency of future monitoring methods of urban areas. 3) Urban expansion data have become the prerequisite for recognizing the urban development process, excavating its driving forces, simulating and predicting the future development directions, and also is conducive to revealing and explaining urban ecological and environmental issues. 4) In the past decades, Chinese scholars have promoted the application of remote sensing technology in the urban expansion field, with data construction, methods and models developing from the quotation stage to improvement and innovation stage; however, an independent and consistent urban expansion data on the national scale with long-term and high-frequency (such as annual monitoring) monitoring is still lacking.  相似文献   
55.
白细胞介素10(Interleukin 10,IL-10)是一种抗炎细胞因子,可以抑制机体免疫反应。本研究经过分析大黄鱼基因组数据库发现了IL-10同源基因,并对其cDNA编码区序列和基因组DNA序列进行了克隆分析。大黄鱼IL-10(LycIL-10)基因由5个外显子和4个内含子构成,其序列全长1 869bp,其开放阅读框(ORF)长555bp,编码184个氨基酸,其N端的22个氨基酸残基为预测的信号肽,成熟肽由162个氨基酸残基组成,包含了脊椎动物IL-10标志性保守序列。LycIL-10的氨基酸序列同其他已知物种的IL-10氨基酸序列的一致性为26.49%~77.01%。Real-time PCR分析发现LycIL-10在检测的组织中为组成型表达,在脾脏和肌肉中转录水平相对较高。三联灭活细菌疫苗和聚肌苷酸胞苷酸(poly(I∶C))刺激后,大黄鱼头肾和脾脏中LycIL-10mRNA的转录水平会显著升高,表明LycIL-10可能参与抑制大黄鱼由细菌和病毒引起的炎症反应。  相似文献   
56.
在分析矿区地形地貌、地层岩性、水文地质条件和影响排土场稳定因素的基础上,结合区内2#排场的监测资料,采用FLAC3D模拟软件和刚体极限平衡法中的毕肖普条分法,对排土场边坡变形、破坏的主要影响因素进行了分析,揭示了其滑坡机理;对3#排土场的稳定性做出预测,认为排土场边坡变形破坏模式是上部排弃物沿圆弧滑面剪切滑移与下部沿粉土、粉质粘土平面滑移的圆弧—平面组合滑移形式;基底土层的内摩擦角对排土场允许排高较为敏感,是决定允许排高的内在因素,基底粉质粘土的极限承载力是决定排土场允许排高的外在因素;基底土体极限承载力所决定的排土场的允许排高为90.60~91.60m。提出了填沟压脚、降低第一排台阶高度和基底排水等措施来满足排土场边坡稳定的要求。  相似文献   
57.
基于2014年河北省CORS观测及气象资料,利用GNSS PWV进行水汽输送路径研究。通过GNSS PWV、ΔPWV变化与实际降水的比较发现,GNSS PWV空间变化与水汽输送路径一致,验证了河北省存在由南向北、由西北向东南的两条水汽输送路径。  相似文献   
58.
Framework of distributed coupled atmosphere-ocean-wave modeling system   总被引:1,自引:0,他引:1  
In order to research the interactions between the atmosphere and ocean as well as their important role in the intensive weather systems of coastal areas, and to improve the forecasting ability of the hazardous weather processes of coastal areas, a coupled atmosphere-ocean-wave modeling system has been developed. The agent-based environment framework for linking models allows flexible and dynamic information exchange between models. For the purpose of flexibility, portability and scalability, the framework of the whole system takes a multi-layer architecture that includes a user interface layer, computational layer and service-enabling layer. The numerical experiment presented in this paper demonstrates the performance of the distributed coupled modeling system.  相似文献   
59.
水力封堵型煤层气藏判识条件分析   总被引:1,自引:0,他引:1  
从宏观和微观两个方面分析了不同条件下煤层气的赋存特征,总结出水力封堵型煤层气藏的判识条件。研究表明,宏观上,可以通过煤储层边界的物理性质进行判识,在煤储层与地下水连通的基础上,分析断层、岩性、地下水三者之间的组合对水力封堵型煤层气藏赋存所起的作用,将水力封堵型煤层气藏划分为地层-水力封堵型、开放性断层-水力封堵型、封闭性断层-水力封堵型、岩性-水力封堵型、开放性断层-岩性-水力封堵型五种类型;微观上,主要通过煤储层流体的化学性质来判识,包括水的矿化度、水化学类型、甲烷碳同位素等三个方面,通常水力封堵型煤层气藏的地层水矿化度低于1 000mg/L,甲烷碳同位素较轻,且水化学类型为NaHCO3型、Na2SO4型或为NaHCO3和Na2SO4混合型。  相似文献   
60.
喀斯特山区城镇边缘带界定及特征研究   总被引:1,自引:0,他引:1  
针对城镇边缘带在空间上存在动态的不确定性问题,该文提出以边缘带土地利用特征(主要指标为建设用地土地利用率与垦殖率)为基础的边缘带相对静态定界体系。采用ArcGIS Python实现体系中的自然断点分类法和空间筛选法,对特定时间节点的喀斯特山区城镇边缘带分布格局进行自动识别。从统计学、景观学探讨静态定界体系中网格参数设置,并从GIS统计分析山区城镇边缘带分布特征。研究表明:研究区域内边缘带约80%面积分布在0~15°坡度带;它与到核心区距离中度相关;山体和河道分布对城镇空间发展的连续性有影响;在交通网络影响下,地貌对边缘带界限的影响减弱,部分边缘带没有与城镇核心区相邻。因此,喀斯特山区小城镇边缘带分布在受地块与核心区之间距离、地形地貌、交通网络空间分布综合影响下,呈"飞地"分布。  相似文献   
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