The Long-term Performance of NOAA’s Operational Open Ocean Tsunameter Array

Abstract:

The National Oceanic and Atmospheric Administration’s (NOAA) National Data Buoy Center (NDBC) has operated and maintained the full 39-station array of open ocean tsunameters since 2008 using the second generation Deep-ocean Reporting and Assessment of Tsunamis technology. The array provides real-time, ocean bottom measurements to Tsunami Warning Centers (TWC) located in Hawai’i and Alaska. These measurements aid them in detecting the presence or absence of tsunamis in the open ocean and in determining the essential characteristics of a tsunami to support the TWC. Thirty-two of the stations span the Pacific Ocean, while seven are located in the Atlantic Ocean, Gulf of Mexico, and the Caribbean Sea. The sensors are located on the ocean floor to depths of 6000 m and the system must deliver measurements from that depth to the TWCs in 3 minutes or less. These vast horizontal and vertical distances and the often extreme conditions of the open ocean raise considerable challenges in maintaining necessary and sufficient measurements to support the TWCs. To support this effort, NDBC aims to maintain and generally achieves a goal of 80% real-time data availability. Data availability is the percentage of measurements received versus the number of expected measurements.

Using seven years of data we examine operational performance parameters such as real-time and retrospective data availability and tsunami detection for trends, patterns, and the factors affecting performance and reliability of the array. We will also discuss the initial results of the Field Evaluation of the 4^th Generation technology.