Observation of Coastal Front and Circulation in the Northeastern Java Sea, Indonesia

The structure and spatial extent of a coastal front and circulation in the shallow (<55 m depth) northeastern Java Sea in Indonesia was investigated with a new dataset of high-resolution conductivity-temperature-depth (CTD) and along-track shipboard acoustic Doppler current profiler (SADCP) during a DIKTI-LIPI 2010 joint research cruise on R.V. Baruna Jaya 8. The coastal front separates fresh warm coastal water derived mainly from Barito River discharge and the saline, cool Java Sea water. The surface fresh water plume extends approximately 760 km from the Barito River estuary to the south, and its thickness varies from the surface to 10 m and 20 m depth, depending on its proximity to the fresh water source. The front is aligned a northeast and east direction, probably related to a meandering of strong northeastward monsoon current in the eastern part of the Java Sea during the observation time

浅い感潮水路における塩分と潮流の空間的および時間的変動性

広島大学(Hiroshima University)博士(工学)Doctor of Engineeringdoctora

山地河川と感潮河口域における河川流量と浮遊土砂濃度のモニタリングに対する音響トモグラフィーの適用

広島大学(Hiroshima University)博士(工学)Doctor of Engineeringdoctora

Ocean Current Measurements: Challenges and Opportunities in the Florida Current

The water velocities offshore south Florida are dominated by the Florida Current, and these effects result not only from the tremendous flow of water between Florida and the Bahamas, but also from the eddies and other rotational components imparted by the change in flow direction from eastward to northward along the Florida Keys and the end of the peninsula. These currents have been measured for decades, with methods ranging from subsurface floats to acoustic Doppler current profilers (ADCPs) and surface current measuring radars. Data suggests that there is a large degree of variability in the mean flow, including significant vorticity events, yet a comprehensive measurement, characterization, and model validation effort of the small timescale variances (hours to days), also known as turbulence, has not been conducted to date. In addition to local effects, the Florida Current has long been of interest because of the central role it must play in the general circulation of the North Atlantic Ocean and its probable role in global climatology. Studies suggest the advection of heat by ocean currents plays a major role in determining climate. The Florida Current is known to be a major transport system for heat flux across 25° N, an important location in the meridional transport of heat in the subtropical gyre. Logistically the Florida Straits have always been attractive to study because it is geographically constrained by the Florida Peninsula and the Bahamas. More recently, the potential for producing a source of clean and renewable base-load power for the Southeast Florida metropolitan area utilizing the current has been proposed. Therefore, the Florida Current has been one of the most studied ocean currents for well over 100 years. The large number of historic measurements provides an opportunity to verify computer models thru hind casting and supplement ongoing measurement and modeling activities. These datasets not only provide historic data at specific times and locations, but also depending on correlation between historic and contemporary measurements, may enable information on climatological trends to be inferred without requiring additional measurements. Past studies utilized a wide range of instruments, from mechanical current meters in the late 1800’s to modern acoustic and radar based systems at the leading edge of modern technology. The advantages of various sensors, as well as their limitations in certain applications, provide guidance on the proper means for additional data collection. A comprehensive review of historical equipment as well as the evolution of modern devices is essential for the informed planning and execution of detailed measurement efforts in the challenging waters of the Florida Current. This document provides information on historical and modern equipment that may enable the measurement of the highly dynamic surface waters of the Florida Current and provide insight on short-term variability and turbulence, as well as information beneficial to new technologies such as ocean energy production

Application of Acoustic Tomography for Gaging Discharge of Atidally Dominated River

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Review of existing and operable observing systems and sensors

Deliverable 1.4 is aimed at identification of existing and operable observing systems and sensors which are relevant to COMMON SENSE objectives. Report aggregates information on existing observing initiatives, programmes, systems, platforms and sensors. The Report includes: • inventory of previous and current EU funded projects. Some of the them, even if started before 2007, were aimed at activities which are relevant or in line with those stemming from MSFD in 2008. The ‘granulation’ of the contents and objectives of the projects varies from sensors development through observation methodologies to monitoring strategies, • inventory of research infrastructure in Europe. It starts from an attempt to define of Marine Research Infrastructure, as there is not a single definition of Research Infrastructure (RI) or of Marine Research Infrastructure (MRI), and there are different ways to categorise them. The chapter gives the categorization of the MRI, together with detailed description and examples of MRI – research platforms, marine data systems, research sites and laboratories with respect of four MSFD descriptors relevant to COMMON SENSE project, • two chapters on Research Programs and Infrastructure Networks; the pan-European initiatives aimed at cooperation and efficient use of infrastructural resources for marine observation and monitoring and data exchange are analysed. The detailed description of observing sensors and system are presented as well as frameworks for cooperation, • information on platforms (research vessels) available to the Project for testing developed sensors and systems. Platforms are available and operating in all three regions of interest to the project (Mediterranean, North Sea, Baltic), • annexed detailed description of two world-wide observation networks and systems. These systems are excellent examples of added value offered by integrated systems of ocean observation (from data to knowledge) and how they work in practice. Report concludes that it is seen a shortage of new classes of sensors to fulfil the emerging monitoring needs. Sensors proposed to be developed by COMMON SENSE project shall answer to the needs stemmed from introduction of MSFD and GES descriptors

Tidal and atmospheric influences on near-surface turbulence in an estuary

Estuarine near-surface turbulence is important for transport, mixing, and air-water exchanges of many important constituents but has rarely been studied in detail. Here, we analyze a unique set of estuarine observations of in situ atmospheric and full water column measurements, estimated air-sea exchanges, and acoustic measurements of several terms in the turbulent kinetic energy (TKE) budget. Observations from a 5.1 m deep site in the Hudson River estuary include dissipation at 50 cm depth (ɛ50), as well as profiles of TKE, shear production of TKE (P), and net turbulent vertical TKE transport (TD). Regressions suggest that the principal controlling factor for ɛ50 was wind (through the surface shear velocity, U*) and that the surface heat flux and tidal currents played a secondary role. For ebb spring tides, the TKE budget at 50 cm depth was closed within noise levels. Ebbs had high ɛ50 due to local shear production, which nearly balanced ɛ50. Floods had TD approaching P in the upper water column but generally weak near-surface shear and turbulence. Examining buoyancy fluxes that impact near-surface stratification and can indirectly control turbulence, solar heat input and tidal straining caused similar buoyancy fluxes on a sunny, calm weather day, promoting ebb tide restratification. Wind-driven mixing was found to dominate during a fall season storm event, and strong overnight heat loss after the storm helped delay restratification afterward. These results demonstrate the utility of combining detailed air-sea interaction and physical oceanographic measurements in future estuary studies

Oceanus.

v. 37, no. 2 (1994