Evaluation of Haney-type surface thermal boundary conditions using a coupled atmosphere and ocean model

A coupled atmosphere-ocean model developed at the Institute for Space Studi es at NASA Goddard Space Flight Center (Russell et at, 1995) was used to ve rify the validity of Haney-type surface thermal boundary condition, which l inearly connects net downward surface heat flux e to air/sea temperature di fference DeltaT by a relaxation coefficient K. The model was initiated from the National Centers for Environmental Prediction (NCEP) atmospheric obser vations for 1 December 1977, and from the National Ocean Data Center (NODC) global climatological mean December temperature and salinity fields at 1 d egrees x 1 degrees resolution. The time step is 7.5 minutes. We integrated the model for 450 days and obtained a complete model-generated global data set of daily mean downward net surface flux Q, surface air temperature T,, and sea surface temperature T,. Then, we calculated the cross-correlation c oefficients (CCC) between Q and DeltaT. The ensemble mean CCC fields show ( a) no correlation between Q and DeltaT in the equatorial regions, and (b) e vident correlation (CCC greater than or equal to 0.7) between Q and DeltaT in the middle and high latitudes. Additionally, we did the variance analysi s and found that when kappa= 120 W m(-2)K(-1), the two standard deviations, sigma (Q) and sigma (kappa DeltaT), are quite close in the middle and high latitudes. These results agree quite well with a previous research (Chu et al., 1998) on analyzing the NCEP re-analyzed surface data, except that a s maller value of kappa (80 W m(-2)K(-1)) was found in the previous study.