Measurement of Net Ocean Surface Heat Flux, Solar Irradiance and Near-Surface Temperature using a Novel Surface Contact Lagrangian Buoy

Development of a 3
^rd
generation light, wave-following surface contact multi-sensor float (SCMsF) is underway. This instrument is designed to simultaneously measure net ocean surface heat flux, solar irradiance, near-surface water temperature and sea state. Whereas the 2
^nd
generation SCMsF design is tethered to a WOCE-type Lagrangian drifter, the 3
^rd
generation is designed to be autonomous. This paper reports preliminary results from a series of experiments performed at a wind-wave-current tank under a variety of meteorological and sea state conditions to assess SCMsF flux and temperature accuracy and operational limits. Comparisons suggest SCMsF net surface fluxes are in generally good agreement with values measured or derived using standard instruments and methods. These experiments also indicate the latest design has significantly improved wave-following characteristics, potentially allowing measurement of net ocean surface heat flux up to wind speeds of 10 m s
^-1
. Infrared imagery of the SCMsF in the wind-wave-current tank and in a rooftop pool suggests the region containing the flux measuring thermopiles is typically 0.5 to 0.9degC cooler than the cool water skin surface. This SCMsF surface temperature offset is relatively insensitive to environmental conditions - even during strong insolation