Operational performance of the second generation deep-ocean assessment and reporting of Tsunamis (DART trade II)

Abstract

In March 2005, the National Oceanic and Atmospheric Administration (NOAA) completed the transition from research to operations of the second generation of the Deep-ocean Assessment and Reporting of Tsunamis (DARTtrade II). DARTtrade II systems are a part of NOAA's Tsunami Program, which is part of a cooperative effort to save lives and protect property through hazard assessment, warning guidance, mitigation, research capabilities, and international coordination. NOAA's National Weather Service (NWS) is responsible for the overall execution of the Tsunami Program. Among its responsibilities under the Tsunami Program, NWS acquires, operates, and maintains observation systems required in support of tsunami warning, such as DARTtrade. NWS also supports observations and data management through the National Data Buoy Center (NDBC). The DARTtrade II systems join NWS base stations, the Tropical Atmosphere Ocean Array, and the Coastal Marine Automated Network stations in the NOAA/NWS/NDBC Ocean Observing System of Systems (NOOSS). In the two years since being declared operational: ldr DARTtrade II systems have replaced all but three DARTtrade I systems, ldr DARTtrade network has expanded to 28 stations stretched across the Pacific and now into the North Atlantic, Caribbean Sea, and the Gulf of Mexico. ldr Three DARTtrade II systems have been provided to other countries to aid in their tsunami warning capability, ldr DARTtrade II systems provided estimated water-level information for the 2006 events in Tonga, Hawai'i, Kuril Islands, and Taiwan. In 2007, DARTtrade II systems provided observations for the Solomon Islands event and another Kuril Islands event. ldr DARTtrade II data availability for the standard mode observations have been more than 85% exceeding the target data availability goal of 80%. DARTtrade II provides increased capabilities over the DARTtrade I systems with the most significant improvement being the additional capability of bidirectional communications from NDBC or the Tsunami Warning Centers (TWCs) to the Bottom Pressure Recorder (BPR) using the commercial Iridium satellite communications system. This capability allows the TWC to set a BPR in event mode and provide high-frequency (1-minute interval) estimated water-level observations and allows the retrieval of up to one hour of the highest frequency (15-second interval) original temperature and pressure counts that can be converted to estimated water-level observations. Furthermore bidirectional communications provides troubleshooting and diagnostic capability in real-time. During the two years since the operational debut of DARTtrade II, NOAA achieved significant accomplishments in data management, including the development of a Tsunami Data Management plan and the establishment of a 24x7 IOOS Data Assembly Center (DAC) at NDBC. The IOOS DAC continuously monitors the NOOSS, including DARTtrade systems, and facilitates the exchange of status information between NDBC and the TWCs. Improvements to the real-time data distribution system included increased system reliability by moving the Iridium communications server and a fail-over web site to Silver Spring MD to co-locate with the National Weather Service Telecommunications Gateway. NDBC's plans include replacing the last three DARTtrade I systems with DARTtrade II systems, the completion of the 39-station DARTtrade network by the end of 2008, increasing the reliability of the systems, and the engineering development of a multi-capability platform.