The Skin-Layer Ocean Heat Flux Instrument (SOHIF). Part II: Field measurements of surface heat flux and solar irradiance

The Skin-Layer Ocean Heat Flux Instrument (SOHFI) described by Sromovsky et al. (Part I, this issue) was field-tested in a combination of freshwater a nd ocean deployments. Solar irradiance monitoring and field calibration tec hniques were demonstrated by comparison with independent measurements. Trac king of solar irradiance diurnal variations appears to be accurate to withi n about 5% of full scale. Preliminary field tests of the SOHFI have shown r easonably close agreement with bulk aerodynamic heat flux estimates in fres hwater and ocean environments (generally within about 20%) under low to mod erate wind conditions. Performance under heavy weather suggests a need to d evelop better methods of submergence filtering. Ocean deployments and recov eries of drifting SOHFI-equipped buoys were made during May and June 1995, during the Combined Sensor Program of 1996 in the western tropical Pacific region, and in the Greenland Sea in May 1997. The Gulf Stream and Greenland Sea deployments pointed out the need for design modifications to improve r esistance to seabird attacks. Better estimates of performance and limitatio ns of this device require extended intercomparison tests under field condit ions.