On the basis of thermodynamic considerations, a relationship between overwater Bowen ratio, B, and sea–air temperature difference, (Tsea − Tair), under unstable conditions has been formulated by Hsu (1998). The purpose of this note is to further support the proposed general form that B = a(Tsea − Tair)b, where a and b are to be determined from field experiments.
Datasets incorporated into this study as shown in Fig. 1 are based on Table 1 as provided by Yasuda (1975) from measurements made in the East China Sea during winter. Table 2 is based on Pond et al. (1971) from data collected during the Research Platform FLIP cruises off San Diego, California, and in the equatorial Atlantic Ocean. Figure 1 shows our results, where (Tsea − Tair) has extended to about 13°C and B to over 0.5. If one accepts the high correlation coefficient of 0.94 [i.e., the equation provided in Fig. 1 can directly account for(0.94)2 = 88% of the variability in B], Fig. 1 may be useful from the tropical ocean to the cold air outbreak region such as over the East China Sea. The composite values of a (=0.146) and b (=0.49) are also provided in Fig. 1.
Acknowledgments
The AMTEX Data Reports and related scientific papers including those data used here were provided by Drs. Y. Mitsuta and M. Yasushi, Disaster Prevention Research Institute, Kyoto University, Kyoto, Japan.
REFERENCES
Hsu, S. A., 1998: A relationship between the Bowen ratio and sea–air temperature difference under unstable conditions at sea. J. Phys. Oceanogr.,28, 2222–2226.
Pond, S., G. T. Phelps, J. E. Paquin, G. McBean, and R. W. Stewart, 1971: Measurements of the turbulent fluxes of momentum, moisture, and sensible heat over the ocean. J. Atmos. Sci.,28, 901–917.
Yasuda, N., 1975: The heat balance at the sea surface observed in the East China Sea. The Science Reports of the Tohoku University, Series 5, Geophysics, Vol. 22, No. 3–4, 87–105.
A relationship between the Bowen ratio and sea–air temperature difference.
Citation: Journal of Physical Oceanography 29, 6; 10.1175/1520-0485(1999)029<1372:OTEOOB>2.0.CO;2
Daily mean values for parameters used to compute B in the East China Sea in Feb 1974 (based on Yasuda 1975, Tables 1 and 2).*
List of Bowen ratio vs Tsea − Tair (in °C) for the equatorial Atlantic Ocean and off California (based on Pond et al. 1971, Table 1 and appendix).
