To detect eddies, intensive surveys of the northeast South China Sea (SCS) (114°30′– 121°30′ E, 17°–22°N) were conducted in July 1998 during the international SCS Monsoon Experiment (SCSMEX), the U.S. Navy using Airborne Expendable Bathythermograph and Conductivity-Temperature-Depth sensors (AXBT/AXCTD), and the Chinese Academy of Sciences using Acoustic Doppler Current Profilers (ADCP). The hy...

As part of the EU funded OMEGA project a cruise to the Eastern Alboran (Western Mediterranean) was carried out on board RRS Discovery during December 1996 and January 1997. During the cruise, a fine scale survey, designed to be oriented along ERS ground tracks, was repeated several times. Several additional survey legs were carried out, part of which lay along additional ERS or TOPEX/POSEIDON a...

The objective of this project is to develop and support the capability for synoptic and pseudo synoptic data collection through simultaneous operation of multiple AUVs. The goal is to use synoptic and pseudo synoptic measurements to efficiently characterize near land shallow water and sea bottom environments. An emphasis will be placed on shallow water hydrographic survey and locating and mappi...

[1] Secondary circulation, referring to the motion relative to a basic flow (geostrophic and hydrostatic balanced), occurs often in the ocean such as deep convection and circulations driven by fronts and eddies. It affects the general circulation and the mass, heat, salt, and energy balance. The oceanic secondary circulation is difficult to measure directly, but is easy to be identified by pseu...

The paper describes how historical geographical data in the form of depth soundings have been used to improve the understanding of hydroacoustic signal propagation through a large ducted water channel. The geo-computational elements of the paper fit within the larger framework of research into underwater vehicles, subsea communications and imaging, carried out by the Ocean Systems Laboratory ov...

A number of GPS augmentation systems have recently been developed for different applications in various regions. The manufacturers of these commercial services claim decimeter or near-decimeter level (1σ) horizontal positioning precision. These systems provide different types of correction and integrity signals to users via satellite links. Three services were studied: the NavCom Technology, In...

The Differential Global Positioning System (DGPS) is a marine navigation system operating at frequencies of 283.5–325 kHz, which now the primary method for locating vessels in coastal shipping, as well hydrography and mapping systems worldwide. Its positioning accuracy determined by following: pseudorange error to (GPS) satellites, age corrections, value Horizontal Dilution Precision (HDOP), wh...

A large number of genera in the tropical fish family Characidae are incertae sedis. Cytogenetic analysis was made of four of these species: Astyanax eigenmanniorum, Deuterodon stigmaturus, Hyphessobrycon luetkenii, and H. anisitsi, collected from various hydrographic basins: hydrographic system from Laguna dos Patos/RS, Tramandaí basin/RS and Tibagi River basin/PR. The first two species we...