Evidence for complete and partial surface renewal at an air-water interface

[1] A wind-wave flume is used to determine the extent to which the thermal boundary layer (TBL) at a wind-forced air-water interface is completely renewed from below. We measure skin temperature, Tskin, radiometrically, temperature immediately below the TBL, Tsubskin, using a temperature profiler, and net heat flux using the gradient flux technique. The Tskin probability density function, p(Tskin), and surface renewal time scale, t, were measured using passive and active infrared imaging techniques, respectively. We find that the mean percentile rank of Tsubskin in p(Tskin) is 99.90, implying that complete surface renewal occurs. This result suggests an alternative to radiometric measurement of Tskin through the simple combination of an infrared camera and an in situ temperature sensor. Comparison of the temperature difference across the TBL to the expected cooling implies that a significant portion of events only partially renew the TBL. This result should impact efforts to improve air-sea transfer models. Citation: Jessup, A. T., W. E. Asher, M. Atmane, K. Phadnis, C. J. Zappa, and M. R. Loewen (2009), Evidence for complete and partial surface renewal at an air-water interface, Geophys. Res. Lett., 36, L16601, doi:10.1029/ 2009GL038986.