计算机辅助编绘-钱塘江海塘带状地形图

钱塘江海塘,担负着保护杭嘉湖平原及肖绍平原免受洪、潮灾害的重大使命,近年钱塘江海塘险情迭出。建造能抗御百年一遇洪、潮灾害和12级台风的水上长城——钱塘江标准海塘已经是刻不容缓,追在眉睫。而修建标准海塘的研究、设计、立项等前期工作都离不开钱塘江海塘带状地形图,并且对信息需求量越来越大,要求成图周期缩短,     

Tidal analysis in the venturi-shaped area between Zhenhai and Shenjiamen in the East China Sea

In order to better understand the general tidal features in the venturi-shaped area between Zhenhai and Shenjiamen in the northern coastal region of Zhejiang Province in the East China Sea, the tidal data were obtained from both the three permanent tide stations of Zhenhai, Dinghai and Shenjiamen, and four temporary tide stations of Mamu, Chuanshan, Guoju and Liuheng, along with the current speed being observed at Luotou Waterway. Results from harmonic analysis show that: (1) The area was dominated by shallow water tides with irregular semi-diurnal features, and the smallest tidal range occurred in the area near a crossing line between Zhenhai and Dinghai stations, indicating that a tidal node existed in the southern Hangzhou Bay; (2) Formulae, HS2/HM2 >0.4 and gM2-(gK1+gO1)=270° (where H and g are harmonic constants), could be used as judging criteria for high and low tidal level diurnal inequalities; (3) The duration difference between ebb and flood tides could be roughly assessed by the ratio of HM4 vs. HM2; and the larger the ratio is, the bigger the duration difference is. At the same time, the duration period could be assessed by 2gM2-gM4, the epoch difference between M2 and M4 tidal constituents. If 2gM2-gM4 <180°, then the ebb duration is longer than the flood duration; if 180°< 2gM2-gM4 <360°, the result is reversed; (4) Taking Dinghai station as a center point, the highest tidal levels and the average high tidal levels, as well as the average tidal ranges at all stations became higher and larger both southeastwards and northwestwards, while the lowest tidal levels and the average low tidal levels appeared to be lower both southeastwards and northwestwards; and (5) The tidal patterns were not all in line with the tidal current patterns. As a conclusion, the smallest tidal range occurred in the narrow part of the venturi-shaped area. Along the both sides of the area, the highest tidal level and tidal range became higher and larger, while the lowest tidal level became lower with the increase of the distance from the narrow throat area. This is somehow different from the theory that the tidal level increases gradually when it moves towards the top narrow area of a V-shaped bay or estuary.     

应用导航型GPS定位系统进行小比例尺水深测量的探讨

美国天宝（Trimble）导航公司生产的Navtrac GPS接收机，以它的良好导航性能，经济的价格，广泛应用于各种船舶的导航。但用该GPS进行小比例尺水深测量（动态）的测点定位，尚没有成熟的经验。我队干1994年初，购置了两台NavtracGPS，并配置两台便携式计算机，通过测试和现场实践，     

侧扫声纳探测水下障碍物时拖曳速度的探讨

本文介绍了影响侧扫声纳拖曳速度因子，并提出了实际工程中设计拖曳速度的一般方法。     

测船航速一全站仪极坐标法水下地形测量定位精度的保障

水下地形测量中,定位是一个重要的组成部分,定位精度的高低,直接关系到水下地形图所表示的水下地物、地貌的正确性。不同比例尺的水下地形测量的定位精度,必须采用相应精度的定位方法来保障,目前常用的定位方法有：前方交会法、后方交会法、侧方交会法、极坐标法、无线电定位法、GPS差分定位法及水下声学定位等。