Comparison of Tropical Atmosphere Ocean (TAO) Array Flux sensors at 00° 140°W

As part of the transition from the originators of the Tropical Atmosphere Ocean (TAO) Array, NOAA´s Pacific Marine Environmental Laboratory (PMEL), to the National Data Buoy Center (NDBC), obsolescent sensors that are currently on the TAO Legacy buoys will be replaced by commercial off-the-shelf (COTS) sensors that will be on the TAO Refresh buoys. Side-by-side testing of a number of the moorings is being conducted. One of the comparison sites is at the equator and 140°W, where a flux site is located. A flux site consists of the seventeen sensors that are normally at a TAO buoy site, plus an additional sixteen meteorological and oceanographic sensors. The Refresh mooring at 00° 140°W was deployed for approximately 375 days with a visit eight months after deployment to replace the air temperature - relative humidity sensor and the rain gauge. Therefore, the comparison is separated into two portions. The sensors being compared include meteorological sensors such as anemometers, air temperature and relative humidity sensors, Additional meteorological sensors at flux sites include short-wave and long-wave radiometers, barometers, and rain-rate sensors. TAO ocean sensors include sea surface temperature and conductivity (salinity is derived), and a string of eight temperature sensors and two temperature sensors with pressure to 500 meters depth. The flux sites include four or five single point current meters with associated temperature sensors, in addition to temperature sensors at 5 and 10 meter depths. High-resolution 10-minute data are the basis for comparison. In some cases, daily averages are compared due to the lack of high-resolution data from the Legacy buoy. The means and standard deviations for the Legacy and Refresh wind speed and direction, air temperature, relative humidity, short-wave radiation, and barometric pressure are compared. The mean and standard deviation of the difference between the sensors, the difference root mean squar- value and the maximum and minimum differences are also presented. Finally, the slope and intercept values for the regression between the two sensor time series are presented. The same statistical testing is applied to the surface temperature and salinity values, the subsurface temperatures and pressures, and the time series of current speed and direction from the subsurface point source current meters. Ideally, the results will fall within the accuracy values for the specific sensors being compared. Any discrepancies in the data will be noted and investigated. Information on the condition of the buoy and instruments upon recovery will be incorporated into the evaluation. Additionally, any activity noted during the daily quality control of the data will be utilized and applied, as necessary. Post-deployment calibrations will be performed on all instruments after data is downloaded to ensure their accuracy.