Preliminary results of 4-D water vapor tomography in the troposphere using GPS   总被引：8，自引：2，他引：6  

毕研盟  毛节泰  李成才 《大气科学进展》2006,23(4):551-560

Slant-path water vapor amounts (SWV) from a station to all the GPS (Global Positioning System) satellites in view can be estimated by using a ground-based GPS receiver. In this paper, a tomographic method was utilized to retrieve the local horizontal and vertical structure of water vapor over a local GPS receiver network using SWV amounts as observables in the tomography. The method of obtaining SWV using ground-based GPS is described first, and then the theory of tomography using GPS is presented. A water vapor tomography experiment was made using a small GPS network in the Beijing region. The tomographic results were analyzed in two ways: (1) a pure GPS method, i.e., only using GPS observables as input to the tomography; (2) combining GPS observables with vertical constraints or a priori information, which come from average radiosonde measurements over three days. It is shown that the vertical structure of water vapor is well resolved with a priori information. Comparisons of profiles between radiosondes and GPS show that the RMS error of the tomography is about 1–2mm. It is demonstrated that the tomography can monitor the evolution of tropospheric water vapor in space and time. The vertical resolution of the tomography is tested with layer thicknesses of 600 m, 800 m and 1000 m. Comparisons with radiosondes show that the result from a resolution of 800m is slightly better than results from the other two resolutions in the experiment. Water vapor amounts recreated from the tomography field agree well with precipitable water vapor (PWV) calculated using GPS delays. Hourly tomographic results are also shown using the resolution of 800 m. Water vapor characteristics under the background of heavy rainfall development are analyzed using these tomographic results. The water vapor spatio-temporal structures derived from the GPS network show a great potential in the investigation of weather disasters.  相似文献   

A new pelagic Polyconchoecia Xiang, Chen and Du, 2018 (Ostracoda: Myodocopa: Halocyprididae) from the South China Sea     

项鹏  王雨  陈瑞祥  叶又茵  王春光  陈小银  林茂 《海洋学报(英文版)》2020,39(4):73-83

Halocyprid ostracods are appreciable part of ostracods floating through virtually everywhere in marine environment.In this study,we describe a new species of genus Polyconchoecia Xiang,Chen and Du,2018,tribe Conchoeciini Chavtur and Angel,2011,family Halocyprididae Dana,1853 from the middle of the South China Sea.Polyconchoecia chenii sp.nov.is very close to P.commixtus Xiang,Chen and Du,2018.But it differs from P.commixtus by the distinctions of locations of major glands of carapace and the characteristics of appendages:more posteriorly situated left asymmetric gland of carapace,no right asymmetric gland;segmented frontal organ;the endopod 2 of the first antenna with a very small seta;a-and c-setae of the first antenna with long end joint have long end joint,the b-and d-setae have no end joint,spinose e-seta without end joint;the e-seta of the second antenna is present;teeth side is distinctive;the setal counts of the mandible,maxilla,fifth limb,and sixth limb are individual.The locations of the major glands on carapace and the characteristics of the first antenna can be the key of the new species.This work is the second discovery of the genus Polyconchoecia from the world.  相似文献   

基于自动探测方法的南海北部涡致海表温度锋面的特征研究   总被引：1，自引：0，他引：1  

邱春华  欧阳娟  俞建成  毛华斌  戚永锋  吴加学  苏丹仪 《海洋学报(英文版)》2020,39(11):82-90

南海北部具有丰富的温度锋面和中尺度涡,它们调节着局地的热量和能量平衡。本文利用卫星海洋高度异常和海表温度数据,并基于自动探测方法,探究了2007年至2017年南海北部中尺度涡边缘的海表温度锋面（涡致锋面）特征。反气旋/气旋边缘出现锋面的概率可达20%。气旋涡在各个方向上出现锋面的概率比较均匀,反气旋涡的东北部和西南部出现锋面的概率大于西北部和东南部。中尺度涡致锋面的数量有明显的季节变化,而涡动能未表现出明显的季节变化。中尺度涡致锋区的总涡动能是中尺度涡内动能的3倍,并且反气旋涡致锋面的总涡动能明显强于气旋涡致锋面的总涡动能。中尺度涡致锋面的数量和涡动能的年际变化与厄尔尼诺南方涛动指数没有明显的相关性。本研究也讨论了中尺度涡致锋面的可能机制,但是中尺度涡对海表温度锋的贡献需要进一步定量研究。  相似文献   

Influence Analysis and Vibration Restraint Solutions Research on the Underwater Acoustic Monitoring System     

Wang  Zhen  Zheng  Yi  Mao  Yu-feng  He  Chuan-lin  Gong  Jin-long  Hao  Zong-rui 《中国海洋工程》2020,34(5):718-729

China Ocean Engineering - In order to reduce the hydrodynamic and structural influences on the detection accuracy especially in the very-low-frequency range, some vibration restraint methods are...  相似文献   

Exploring Spatially Non-stationary Relationships in the Determinants of Mineralization in 3D Geological Space     

Huang  Jixian  Mao  Xiancheng  Chen  Jin  Deng  Hao  Dick  Jeffrey M.  Liu  Zhankun 《Natural Resources Research》2020,29(1):439-458

Exploring the spatial relationships between various geological features and mineralization is not only conducive to understanding the genesis of ore deposits but can also help to guide mineral exploration by providing predictive mineral maps. However, most current methods assume spatially constant determinants of mineralization and therefore have limited applicability to detecting possible spatially non-stationary relationships between the geological features and the mineralization. In this paper, the spatial variation between the distribution of mineralization and its determining factors is described for a case study in the Dingjiashan Pb–Zn deposit, China. A local regression modeling technique, geological weighted regression (GWR), was leveraged to study the spatial non-stationarity in the 3D geological space. First, ordinary least-squares (OLS) regression was applied, the redundancy and significance of the controlling factors were tested, and the spatial dependency in Zn and Pb ore grade measurements was confirmed. Second, GWR models with different kernel functions in 3D space were applied, and their results were compared to the OLS model. The results show a superior performance of GWR compared with OLS and a significant spatial non-stationarity in the determinants of ore grade. Third, a non-stationarity test was performed. The stationarity index and the Monte Carlo stationarity test demonstrate the non-stationarity of all the variables throughout the area. Finally, the influences of the degree of non-stationary of all controlling factors on mineralization are discussed. The existence of significant non-stationarity of mineral ore determinants in 3D space opens up an exciting avenue for research into the prediction of underground ore bodies.

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潮汐调和分析的一种算法   总被引：1，自引：1，他引：1  

宋志尧  严以新  茅丽华 《海洋工程》1997,(3)

本文在常规潮汐调和分析方法的基础上，提出了一种由高低潮资料进行潮汐分析的算法。具体计算表明，该算法与现今通用的常规算法（即等间隔最小二乘法）相比，既可大大减少所需原始样本量，在相同记录长度内，是常规算法的三分之一还少，同时减少样本处理的前期工作量；又能保证潮位拟合的精度和预报的可信度，两者精度相当，结果一致。该算法原理简单、实用有效，对于局部样本缺损较易处理，具有实际应用价值。  相似文献   

温度和体重对花尾胡椒鲷幼鱼最大摄食量的影响     

王瑁  丘书院 《台湾海峡》2000,19(4):484-488

研究了花尾胡椒鲷幼鱼的最大摄食量与温度和体重的关系。花尾胡椒鲷幼鱼的最大摄食量与体重呈正相关 ,二者的关系为 :Cmax=1 5 95 .3W0 .6 87(Cmax:最大摄食量 ,J/d ;W :体重 ,g)。最大摄食量随温度的变化情况为 :在实验温度为 2 2～ 2 8℃范围内 ,二者呈正相关 ,超过 2 8℃之后呈负相关。最大摄食率与体重的相关关系为 :Rmax=1 5 0 7.6W-0 .313[(Rmax:最大摄食率 ,J/(d·g) ]。采用回归分析 ,建立了由温度和体重预测该种鱼的最大摄食量和最大摄食率的模型 :Cmax=2 86 790e-0 .90 4ln(T3-77.738T2 1985 .185T -16 42 9.710 ) W0 .6 16 　n =1 6 ,r =0 .994Rmax=0 .887e1.2 6 4ln(-T3 78.0 6 1T2 -2 0 0 3.397T 172 36 .5 2 0 ) W-0 .2 83　n =1 6 ,r=0 .978  相似文献   

1998年夏季南海水团分析   总被引：8，自引：0，他引：8  

刘增宏  李磊  许建平  侍茂崇 《海洋学研究》2001,19(3):1-10

根据 1 998年夏季“南海季风试验 ( SCSMEX)”期间所获的 CTD资料 ,使用系统聚类、Fuzzy模式聚类、Bayes判别分析和 Fuzzy分析等水团分析方法 ,对南海水体的结构和水团配置状况等进行了分析 ,划出了南海存在的 9个主要水团 ,并对各水团的温、盐度特征进行了初析。在调查期间 ,南海本地水 (南海水 )几乎控制了整个调查海区 ,而黑潮水仅出现在台湾岛的西南海域 ;海水强烈混合发生在吕宋海峡附近 ;在中南半岛以东和吕宋岛以西海域 ,表层水明显下沉 ;在南海东南部可能有来自苏禄海的海水 ,其温、盐度特征类似于吕宋海峡中的黑潮水  相似文献   

台湾岛以东海域束毛藻种群的组成与分布   总被引：2，自引：0，他引：2  

王雨  林茂  杨清良  林更铭 《海洋通报》2012,31(4):426-432

分别对1996年5月和1997年7月台湾岛以东黑潮及邻近海域51个采样站位的87份网采浮游植物进行了分析,总结了束毛藻种群的物种构成和丰度分布特征,并初步探讨了水动力条件、温盐、营养盐及其他元素对束毛藻生长及分布的影响.结果表明,调查区的束毛藻种群由铁氏束毛藻(Trichodesmium thiebautii)、汉氏束毛藻(Trichodesmium hildebrandtii)和红海束毛藻(Trichodesmium erythraeum)组成,前者分布最为普遍,检出率100%,丰度最大.1996年5月束毛藻平均藻丝体密度为44.55伊102 filaments/m3,铁氏束毛藻占91%,在吕宋海峡密集,总体呈现西南高,东北低的分布态势.1997年7月束毛藻平均藻丝体密度为152.72伊102 filaments/m3,铁氏束毛藻占99%,除吕宋海峡外,台湾东北部海域为次高值区,总体呈现西南高,中部和东部低的分布态势.较之邻近海区结果,台湾岛以东黑潮及邻近海域的束毛藻平均藻丝体密度高于太平洋赤道热带海域、南黄海和东海陆架区、东海产卵场,低于台湾海峡西侧20 m 以浅和东海低氧区.在台湾岛以东海域,束毛藻的丰度分布由其特定的地理位置和黑潮流向所决定,高温高盐的黑潮水系利于束毛藻的增殖,束毛藻的丰度分布与 Fe、P 等化学因子的关系有待进一步寻找证据.  相似文献   

Tide-induced Lagrangian residual velocity and dynamic analysis based on field observations in the inner Xiangshan Bay,China     

Xiaoxuan Sheng  Qi Quan  Jinzhen Yu  Xinyan Mao  Wensheng Jiang 《海洋学报(英文版)》2022,41(10):32-40

In the Xiangshan Bay at the east coast of China, coastal marine pollution is conspicuous and severe in recent years. As transport of the pollutants is closely related to the coastal circulation, there is a great practical significance to investigate the circulation in this area. In this work, the surface pattern and vertical profiles of Lagrangian residual velocity (LRV) were studied based on field observation data from the inner Xiangshan Bay. By tracking GPS-GPRS drifters’ trajectories, the surface LRV pattern is going out in the central deep trough and flowing inwards near the shoreside. Combined with data from two mooring stations, vertical profiles of LRV is flowing out at surface and flowing in at the bottom, consistent with the gravitational circulation induced by baroclinic effects at the estuary. However, according to the diagnostic analysis, the main mechanism driving the residual current is barotropic rather than baroclinic. The LRV equation is controlled by the tidally-averaged barotropic pressure gradient force, tidal body force and tidally-averaged turbulent stress, while the tidally-averaged baroclinic pressure gradient force is one order of magnitude less than other forces. Additionally, the tidally mean eddy viscosity coefficient which is used in the expression of tidally-averaged turbulent stress might be not adequate and requires further studies.  相似文献