Effect of air-sea exchange parameters on ocean model simulations: comparison with TRITON observations

Abstract

A detailed analysis and validation of ocean thermodynamic variables, simulated, using an Ocean general circulation Model (OGCM) forced by QuikSCAT scatterometer (QS-R) has been carried out in this study. The results are discussed in terms of comparison of vertical profiles of temperature against TRITON observations for the year 2004. Root mean square error (RMSE) of Sea Surface Temperature (SST) simulated by QS-R showed an error of the order of 0.6°C. QS-R SST also has a cooler bias. Another OGCM simulation was carried out in which the National Center for Environmental Prediction (NCEP) reanalysis winds (NCEP-R) were used to force the OGCM. The simulated SST resulted in lesser RMSE (~0.5°C) and there was no bias. However, variabilities in SST were captured more realistically in scatterometer forced solution. However the RMSE in SST was higher which could be partly due to physical inconsistency between scatterometer winds and other air-sea exchange parameters used from NCEP. A detailed statistics of the model simulated temperatures at different depths show excellent performance of scatterometer forced simulations as compared to NCEP-R. Maximum error in the temperature profile was in the thermocline region (~1.5°C) in QS-R as against 3.5°C in NCEP-R. Possible causes of these errors in relation to air-sea exchange parameters used in forcing the OGCM are described in this work.