多波束与RTK三维水深测量技术的联合应用     

王建忠  王玉龙 《测绘工程》2014,(4):65-68

介绍多波束测深系统的构成、工作原理、作业方法,以及RTK三维水深测量技术的理论依据,通过在渤海湾航道水深测量的工作实践,证明使用多波束系统结合RTK三维水深测量技术联合作业,可以得到令人满意的测量精度。  相似文献   

伶仃洋夏季叶绿素a时间变化特征及分析     

曾滇婷  李君益  谢玲玲  叶小敏  周达 《热带海洋学报》2022,41(2):16-25

文章使用2019年7月5日—20日在珠江河口伶仃洋定点连续观测的海表面叶绿素a质量浓度、海表面气温、气压、风速、风向、海表温度、盐度、流速、流向、遥感降雨量数据和中等分辨率成像光谱仪可见光波段影像, 利用小波分析和集成经验模态分解方法分析了观测期间内伶仃洋海表面叶绿素a的时间变化特征及其影响因子。分析结果表明, 观测期间海水表层叶绿素a质量浓度的变化范围为0.44~1.75µg·L^-1, 平均值为0.80µg·L^-1, 其变化周期主要为6h、12h和24h。其与相对应周期的潮流存在明显的相位关系, 并且在降雨后两者的相位关系发生了转换。7月5日—12日, 叶绿素a与潮流基本呈反相位关系, 涨急时叶绿素a质量浓度低, 落急时叶绿素a质量浓度较高, 浓度相差约为0.3µg·L^-1。珠江流域在7月8日—13日发生了一次强降雨过程, 降雨前后海水表层叶绿素a质量浓度在6h、12h和24h周期波段的振幅由0.02~0.09µg·L^-1增加到0.15µg·L^-1左右。同时, 降雨对珠江河口的叶绿素a质量浓度造成了一个持续80h的增加过程, 浓度增加了0.3µg·L^-1。发生降雨后, 7月13日—20日期间潮流滞后于叶绿素a约6h, 水位最高时叶绿素a质量浓度最低, 水位最低时叶绿素a质量浓度最高。由以上结果可以看出, 降雨不仅引起了河口区叶绿素a质量浓度的增加, 还造成了叶绿素a和潮流间相位关系的转换。  相似文献   

Pedoiogisk kortlægning og jordbundsbonitering i et geestrandområde ved Tønder     

BJARNE HOLM JAKOBSEN M.Sc. 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):17-32

Jakobsen, Bjarne Holm: Pedoiogisk kortlægning og jordbundsbonitering i et geestrandområde ved Tønder. Geografisk Tidsskrift 81: 17–32. København, Juni 1, 1981.

The result is presented of a detailed pedological survey of the geest at the margin of the Tønder Marsh-Area. Maps showing the parents sediments, the pedology and the drainage class have been constructed. Furthermore a soil capability map is shown using the land valuation principles of the Federal Republic of Germany.  相似文献   

Indgået til redaktionen     

Karen Edelvang M.Sc.  Michael Larsen M.Sc.  assoc. prof. Morten Pejrup Ph.D. 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):116-119

Edelvang, Karen; Larsen, Michael; Pejrup, Morten: Tidal Variation in Field Settling Velocities of Suspended Sediment in a Tidal Channel. Geografisk Tidsskrift 92:116–121. Copenhagen 1992.

Particles of silt and clay may form large, low density floes when suspended in salt water. The sediment floes have settling velocities much higher than the single small particles constituting them and therefore, the flocculation process may strongly influence the transport of cohesive sediment in estuarine environments. will be described in this paper, the field settling velocities of suspended sediment were investigated in a large tidal channel with tidal current velocities up to 1.3 m/s and depths of about 10 m. The analyses of suspended sediment were made on both bottom and surface samples. For the bottom samples, equivalent median fall diameters in the range 26–98 μm were measured. For surface samples, the range was 15–40 μm. During most of the tidal period, the occurrence of much larger settling diameters near the bottom was due to the suspension of individual sand and silt particles. For the investigated periods, high-tide was the only possible time to observe flocculation influencing the vertical distribution of finegrained sediment in the water column.  相似文献   

长周期潮汐与全球地震能量释放          下载免费PDF全文

解朝娣  吴小平  雷兴林  冒蔚  孙楠 《地球物理学报》2013,56(10):3425-3433

采用1850-2012年期间USGS全球M≥5.0地震目录资料,构成全球地震能量-时间序列,进行小波变换和准周期分析. 结果表明,全球地震能量释放的时间序列存在9年、19年和45年的3个准周期,其中,45年准周期最为突出. 结合起潮力周期的物理背景,对长周期潮汐起潮力与地震能量释放准周期的关系进行了探讨,没有发现全球地震活动的能量释放与潮汐短周期相关的准周期.  相似文献   

A coupled analytical model for salt intrusion and tides in convergent estuaries     

Huayang Cai  Hubert H. G. Savenije  J. I. A. Gisen 《水文科学杂志》2013,58(2):402-419

ABSTRACT

In this paper we develop a coupled analytical model for salinity and tidal propagation in estuaries where the cross-sectional area varies exponentially. A simple analytical model for tidal dynamics has been used to estimate the tidal excursion, which has an important influence on the salt intrusion process since it determines the extreme salinities (i.e. salinity distribution for high water slack and low water slack). The objective of the coupling is to reduce the number of calibration parameters, which subsequently strengthens the reliability of the salt intrusion model. Moreover, the coupling enables us to assess the potential impacts of external changes, both human-induced interventions (e.g. dredging) and natural changes (e.g. global sea level rise), on the salt intrusion process. In addition, the fully analytical solution for hydrodynamics allows immediate estimation of the tidally averaged depth and friction coefficient for given water level recordings and salinity measurements. This is particularly useful when a geometric survey is not available. The coupled model has been applied to six previously unsurveyed estuaries in Malaysia and the results show that the correspondence between analytical estimations and observations is very good. Thus, the coupled model proves to be a useful tool to obtain estimates of salt intrusion in estuaries based on a minimum amount of information required and for assessing the effect of human-induced or natural changes.