Direct measurement of dissolved N2 and denitrification along a subtropical river-estuary gradient,China     

Jiezhong Wu  Nengwang Chen  Huasheng Hong  Ting Lu  Longjian Wang  Zhuhong Chen 《Marine pollution bulletin》2013,66(1-2):125-134

The spatial pattern and seasonal variation of denitrification were investigated during 2010–2011 in the Jiulong River Estuary (JRE) in southeast China. Dissolved N₂ was directly measured by changes in the N₂:Ar ratio. The results showed that excess dissolved N₂ ranged from ?9.9 to 76.4 μmol L^?1. Tidal mixing leads to a seaward decline of dissolved gaseous concentrations and water–air fluxes along the river-estuary gradient. Denitrification at freshwater sites varied between seasons, associated with changes in N input and water temperature. The denitrification process was controlled by the nitrate level at freshwater sites, and the excess dissolved N₂ observed at the tidal zone largely originated from upstream water transport. Compared to other estuaries, JRE has a relative low gaseous removal efficiency (E_d = 12% of [DIN]; annual N removal = 24% of DIN load), a fact ascribed to strong tidal mixing, coarse-textured sediment with shallow depth before bedrock and high riverine DIN input.  相似文献   

自然伽马拟声波曲线构建技术探讨     

查华胜  ;甘志超  ;刘卫佳  ;卞振平  ;徐翠云  ;于卓  ;盖一新 《中国煤炭地质》2014,(5):58-62

声波测井曲线在地震反演中起着约束和控制模型反演的作用,当其不能反映地层岩性变化时,通常会将现有的非声波测井曲线按照一定的经验公式或统计方法来重构新的声波曲线。但是,这些拟声波曲线构建技术并没有考虑到地层岩石孔隙及孔隙中流体的影响。在考虑到岩石孔隙和孔隙中流体的情况下,拟声波曲线构建技术可以先利用岩石基质的声波速度与自然伽马之间的关系来重构具有声波量纲的新曲线,然后结合原声波曲线中能够反映背景速度的低频信息,构建出新的声波曲线。该方法在鄂尔多斯盆地镇泾地区取得了不错的应用效果。  相似文献   

中国近百年雨量与大气环流因子的关系   总被引：11，自引：0，他引：11  

严华生  陈兴芳  谢应齐  曹杰  周传喜 《热带气象学报》1998,14(3):251-257

研究了近百年南方涛动年指数,北半球西风带大气环流Ｗ．Ｃ．环流型年频数对中国大范围年降水量有旱涝的影响,探讨了大气环流因子影响的空间分布变化规律及影响的复杂性,非线性及南北环流不同配置多因子相互作用造成的综合影响特征,发现：（１）ＳＯＩ、Ｗ、Ｗ．Ｃ．Ｅ环流因子对中国降雨的影响不是局地的,而 大范围普遍存在的,只不过对越靠近海洋的地方越显著;（２）并不是单个环流因子的变化就可完全解释清楚雨量的变化,多  相似文献   

ECMWF集合预报产品在广西暴雨预报中的释用   总被引：2，自引：1，他引：2       下载免费PDF全文

赵华生  黄小燕  黄颖 《应用气象学报》2018,29(3):344-353

基于最大相关最小冗余度算法和随机森林回归算法,该文提出一种对欧洲中期天气预报中心（ECMWF）集合预报产品进行暴雨预报的释用方法。该方法采用最大相关最小冗余度算法,对ECMWF集合预报的51个成员进行筛选,选取若干个与预报对象相关性最大、相互间冗余度最小的成员作为随机森林回归算法的输入因子。利用ECMWF集合预报降水量平均值对建模样本进行分类,使预报模型的建模样本更具有针对性。通过2012年4月—2015年12月的交叉独立样本试验预报和2016年1—9月的业务预报试验的统计结果表明:该释用方法的暴雨预报TS和ETS评分,均比采用ECMWF集合预报产品51个成员降水量预报进行插值后取平均值的释用方法分别提高了0.07和0.05以上,显示了较好的数值预报产品释用效果。  相似文献   

利用轻型机机载GPS辅助进行大比例尺地形图航测     

石华胜  王守康  高宇 《测绘通报》2013,(7):46-48

通过对轻型机机载GPS辅助航空摄影进行介绍,以及对其生产应用精度进行分析,探讨一种高精度、快捷、经济的航空摄影测量技术,以期用于国内大比例尺航测生产实践。  相似文献   

Parallel hydrodynamic finite element model with an N-Best refining partition scheme     

Zhang  Zhenchang  Hong  Huasheng  Wai  Onyx Winghong  Jiang  Yuwu  Zhou  Changle 《中国海洋湖沼学报》2010,28(6):1340-1349

We enhance a robust parallel finite element model for coasts and estuaries cases with the use of N-Best refinement algorithms, in multilevel partitioning scheme. Graph partitioning is an important step to construct the parallel model, in which computation speed is a big concern. The partitioning strategy includes the division of the research domain into several semi-equal-sized sub-domains, minimizing the sum weight of edges between different sub-domains. Multilevel schemes for graph partitioning are divided into three phases: coarsening, partitioning, and uncoarsening. In the uncoarsening phase, many refinement algorithms have been proposed previously, such as KL, Greedy, and Boundary refinements. In this study, we propose an N-Best refinement algorithm and show its advantages in our case study of Xiamen Bay. Compared with original partitioning algorithm in previous models, the N-Best algorithm can speed up the computation by 1.9 times, and the simulation results are in a good match with the in-situ data.  相似文献   

厦门市环境灾害防治与区域可持续发展的关系     

陈宗团  薛雄志  江毓武  洪华生 《热带海洋学报》1998,(2)

可持续发展作为一种发展战略已普遍被世界各国所接受。然而,环境灾害的危害是制约一个城市可持续发展的主要因素。厦门市存在包括纯自然作用产生的灾害、纯人为作用产生的灾害和两者结合型的灾害3大类10个亚类。在探讨了厦门市10种灾害的分布与危害后,又讨论集美一高崎的跨海海堤、员当港口海堤（西堤）和马銮海堤3项重大海岸工程对自然环境的重要影响,以及它们引起的对海洋生态的破坏、危及港口的发展和后来人们为了恢复其环境所付出的代价和成功经验,进而阐述环境灾害的预防对厦门市可持续发展的关系。  相似文献   

一种基于统一引力场表示理论的外部扰动场赋值建模方法     

朱灼文  黄金水  操华胜  罗志才 《武汉大学学报(信息科学版)》1999,(2)

提出一种新的外部扰动场赋值的建模方法。该方法将场赋值问题纳入统一引力场表示理论的框架,得到的模式具有结构简单、奇性弱的核,并顾及了地形效应,适合低空引力速算。  相似文献   

一种非线性动力统计模型及其预报试验     

曹杰  陶云  谢应齐  严华生 《热带气象学报》1999,15(2):136-145

在引入样条函数的基础上,设计了一种新的非线性动力统计模型及其一整套反演方案,并用由昆明和蒙自逐月雨量和温度构成的局地气候系统对此模型进行了检验。计算结果表明：（1）无论是在拟会历史气候的变化方面,还是在预测未来气候的变化方面,此模型均具有较高的精度;（2）此模型具有良好的稳定性,历史气候变化的拟合精度和未来气候变化的预测精度相差较小。  相似文献   

Review on current and seawater volume transport through the Taiwan Strait   总被引：12，自引：0，他引：12  

Jianyu Hu  Hiroshi Kawamura  Chunyan Li  Huasheng Hong  Yuwu Jiang 《Journal of Oceanography》2010,66(5):591-610

Patterns and features of currents and seawater volume transports in the Taiwan Strait have been reviewed by examining the results from more than 150 research papers in recent decades. It is noted that there are diverse or even conflicting viewpoints on these subjects. Here both common and different opinions are summarized. This review paper covers the studies involving in situ measurements and numerical modeling of current velocity, analyses of hydrographic data, and classification of water masses. Generally speaking, there are three currents in the Taiwan Strait: the China Coastal Current along the Fujian coast in the western Taiwan Strait, the extension of the South China Sea Warm Current in the western and central Taiwan Strait, and the Kuroshio’s branch or loop current intruding through the eastern Taiwan Strait. The current pattern in winter is quite different from that in summer, and the currents also exhibit differences between the upper and lower layers. The seawater volume transport through the Taiwan Strait is about 2.3 Sv northward in summer but about 0.8 Sv northward in winter. Both the current pattern and the seawater transport vary with local winds in the Taiwan Strait. This is particularly true in winter when the currents and the transport in the upper layer are significantly affected by strong northeasterly winds.  相似文献