Near real-time GPS applications for tsunami early warning systems

GPS (Global Positioning System) technology is widely used for positioning applications. Many of them have high requirements with respect to precision, reliability or fast product delivery, but usually not all at the same time as it is the case for early warning applications. The tasks for the GPS-based components within the GITEWS project (German Indonesian Tsunami Early Warning System, Rudloff et al., 2009) are to support the determination of sea levels (measured onshore and offshore) and to detect co-seismic land mass displacements with the lowest possible latency (design goal: first reliable results after 5 min). The completed system was designed to fulfil these tasks in near real-time, rather than for scientific research requirements. The obtained data products (movements of GPS antennas) are supporting the warning process in different ways. The measurements from GPS instruments on buoys allow the earliest possible detection or confirmation of tsunami waves on the ocean. Onshore GPS measurements are made collocated with tide gauges or seismological stations and give information about co-seismic land mass movements as recorded, e.g., during the great Sumatra-Andaman earthquake of 2004 (Subarya et al., 2006). This information is important to separate tsunami-caused sea height movements from apparent sea height changes at tide gauge locations (sensor station movement) and also as additional information about earthquakes' mechanisms, as this is an essential information to predict a tsunami (Sobolev et al., 2007). <br><br> This article gives an end-to-end overview of the GITEWS GPS-component system, from the GPS sensors (GPS receiver with GPS antenna and auxiliary systems, either onshore or offshore) to the early warning centre displays. We describe how the GPS sensors have been installed, how they are operated and the methods used to collect, transfer and process the GPS data in near real-time. This includes the sensor system design, the communication system layout with real-time data streaming, the data processing strategy and the final products of the GPS-based early warning system components

Report on the Marine Imaging Workshop 2017

Marine optical imaging has become a major assessment tool in science, policy and public understanding of our seas and oceans. Methodology in this field is developing rapidly, including hardware, software and the ways of their application. The aim of the Marine Imaging Workshop (MIW) is to bring together academics, research scientists and engineers, as well as industrial partners to discuss these developments, along with applications, challenges and future directions. The first MIW was held in Southampton, UK in April 2014. The second MIW, held in Kiel, Germany, in 2017 involved more than 100 attendees, who shared the latest developments in marine imaging through a combination of traditional oral and poster presentations, interactive sessions and focused discussion sessions. This article summarises the topics addressed during the workshop, particularly the outcomes of these discussion sessions for future reference and to make the workshop results available to the open public

The checker board counter:a semiconductor de/dx detector with position indication

\u3cp\u3eAs part of an extensive design study for a cyclotron project containing a few hundred semiconductor detectors of different types, we have developed a new version of the (dE/dx) detector as used in (dE/dx * E)telescopes. This checker board counter delivers, besides the ΔE signal, also information about the position of the incident particles. With this detector the angular distributions of charged reaction products can be measured with high angular accuracy in a large solid angle, while slit scattering is eliminated. The checker board counter is essentially a dE/dx detector, which is subdivided in a large number of sensitive fields. These are obtained by placing counter electrodes in the form of parallel strips on each side of the detector in such a way that the back and front side patterns are perpendicular to each other, together forming a rectangular coordinate system. In our case a checker board counter with 88 sensitive fields of 1.37 x 1.37 mm2 maintaining an angular accuracy of 1 degree with an 88-fold increase in solid angle was chosen. Some aspects of the electronic read-out system of the detector are given.\u3c/p\u3