A FURTHER STUDY ON ESTIMATING SURFACE EVAPORATION USING MONTHLY MEAN DATA - COMPARISON OF BULK FORMULATIONS

This study further examines the errors in estimating surface evaporati on using monthly mean surface atmospheric variables from the moored bu oys in the equatorial Pacific. Results from two significantly differen t bulk aerodynamic formulas are compared. It is shown that for both fo rmulas the errors are within 2-3 W m(-2) on average, representing a re lative error of less than 3% in the equatorial Pacific. Although small , this error varies systematically across the equatorial Pacific and d epends on the bulk formula used. It is also demonstrated that the indi vidual nonlinear contributions associated with the strong dependence o f exchange coefficient on surface wind to monthly mean surface evapora tion are significant. However, they largely cancel each other, leaving small net effect.