NDBC Wave Observation Changes

The National Oceanic and Atmospheric Administration's (NOAA) National Data Buoy Center (NDBC) operates a network of over 100 marine weather observation buoys located in the coastal and deep ocean areas of the continental U.S., Great Lakes, Hawaii, and Alaska regions. These buoys use a wave observation system named the Digital Directional Wave Module (DDWM). This NDBC designed system has been in operation since approximately 2009 (“NDBC's Digital Directional Wave Module”, Oceans 2009). Some commercial components of the DDWM are now obsolete. Therefore, the NDBC completed an engineering effort to replace these obsolete components (“NDBC OWL Wave System Development”, IEEE MTS CWTMA, 2019) which created a new wave observation system named Ocean Wave Linux (OWL). The existing DDWM code was ported to the OWL which uses a Linux platform. Extensive testing and debug cycles were completed at NDBC and in co-located field deployments of the OWL and DDWM. These field trials showed that the OWL performed as well as the DDWM. The DDWM is contained in a single package housed in a tube and named WAVCEAN-16 which is a payload in the NDBC's Self-Contained Ocean Observation Payload (SCOOP). WAVCEAN-16 physically contains the Wave and Ocean modules. The Ocean module measures ocean sea surface temperature at a one (1) meter depth. Since the OWL function was proven in field trials, an effort began to modify the WAVCEAN-16 to replace the DDWM components with the OWL components while not changing the Ocean module. This new tube is named WAVCEAN-18. This paper will review those changes, field test results, and other wave observation changes. The WAVCEAN-18 modifications included replacing the metal rack with a 3D printed rack which fixed some testing problems and allows for easier future mounting design changes. A cumbersome prototype wiring harness was replaced with a printed circuit board for cleaner and more reliable wiring connections and signal distribution. Wiring was added to an existing external connector for access to the OWL and motion sensor to support potential debugging activities. Field tests were conducted at NDBC stations 46042 (27NM WNW of Monterey, CA), 46059 (357NM West of San Francisco, CA), and 44014 (64 NM East of Virginia Beach, VA). The tests showed proper operability in that NDBC Technicians and Data Analysts could test, deploy, operate and quality control (QC) the new WAVCEAN-18 system and resulting data. Data availability results met requirements. The overall SCOOP power consumption was lower and matched expectations developed from lab tests. The bulk wave parameters compared well with nearby stations. A detail data analysis including spectral data results remains to be completed. NDBC has also increased wave observations from every sixty (60) minutes to every thirty (30) minutes on both the older WAVCEAN-16 and the newer WAVCEAN-18. The twenty (20) minute observation period and waves processing have not changed; just the reporting frequency. Decreasing power demands from electronics over the years allowed NDBC to make this change and satisfied external groups requests for more frequent wave reports. The paper will conclude with some discussion on future wave observation enhancements NDBC is considering. Presently these include exploring the use of the heave mode from the motion sensor, implementing a maximum wave height observation, and exploring new Iridium satellite transmission capabilities that could be capable of reporting raw motion sensor data from the buoy to shore allowing wave processing to be accomplished completely onshore.