National Data Buoy Center transition of the Tropical Atmosphere Ocean (TAO) program

The National Oceanic and Atmospheric Administration\´s (NOAA\´s) National Data Buoy Center (NDBC) operates and maintains 55 Tropical Atmosphere Ocean (TAO) buoys in the equatorial Pacific Ocean from 9°N latitude to 8°S latitude and 95°W longitude to 165°E longitude. The TAO array was developed after the need was determined following the 1982-1983 El Niño event, which had evaded detection by the science community until well into its maturity. NOAA\´s Office of Oceanic and Atmospheric Research (OAR) Pacific Marine Environmental Laboratory (PMEL) is an interdisciplinary organization whose focal point is collecting open ocean data for monitoring and predicting purposes. PMEL\´s TAO project was created with help from NOAA\´s Equatorial Pacific Ocean Climate Studies (EPOCS) program to enhance the understanding and prediction of El Niño and La Niña events. PMEL completed the TAO array in December of 1994 and in 2005, PMEL began transitioning the TAO array (55 TAO buoys and four Acoustic Doppler Current Profilers (ADCPs)) to NDBC, first in data management and quality control (QC) and later in next-generation creation and implementation of buoys. The technology equipping the TAO array has become obsolescent. Many components are no longer offered or supported by manufacturers, and to maintain the continuity of the TAO array a technological "refresh" was necessary. The data logger and the temperature-conductivity sensors are two of the major refreshed components. Maximum cost-effectiveness was a high priority in the refresh effort. Commercial off-the- shelf (COTS) underwater temperature-conductivity sensors were utilized, as well as a new all-purpose data collection system, the Advanced Modular Payload System (AMPS), and a new Short Burst Data (SBD) Iridium^® (Iridium Communications Inc.) data transmission process. Developed by NDBC, AMPS is also presently deployed on many of NDBC\´s real-time weather b- oys. The refresh effort began in 2006. Since May 2007, NDBC has tested TAO refresh systems to determine their capacity to replace PMEL\´s Autonomous Temperature Line Acquisition System (ATLAS) buoy, which communicates over the Service Advanced Research and Global Observation Satellite (ARGOS) system. Refresh buoys are configured to transmit high-resolution (10- minute) data hourly over the SBD Iridium satellite system, providing a capability only available previously following delayed mode processing. Lab sensor comparisons were conducted between ATLAS and refresh sensors and the performance was found to be favorable. Refresh buoys have been deployed within 10 km of nearby ATLAS buoys for direct comparisons of data quality and data availability. COTS have been proven effective in the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) TRIangle Trans-Ocean buoy Network (TRITON) array. With COTS and AMPS both used across NDBC weather and ocean stations, the maintainability, reliability, continuity, and availability of environmental data will be maximized. Presented are the results of real-time refresh data availability studies, NDBC\´s deployment plan, and how NDBC\´s Data Assembly Center (DAC) will handle the changes in data processing. From June 1, 2010 to June 1, 2011, the refresh buoys at 5°S 140°W, 8°N 155°W, 2°S 170°W, 2°S 165°E, and 8°S 165°E provided high data availability percentages proving that the refresh system can provide data reliability as a replacement for the legacy buoys. NDBC plans to deploy refresh systems in place of legacy systems beginning in August 2011. The abundance of new data made available in real-time presents new challenges for quality control efforts of data in the DAC. One challenge is inductive noise associated with sensors located on the inductive line and new Environmental Quality Control (EQC) limits to address them. It is estimated that th