The Meehanism Of The Wave Indue Mixing Effeot On The Equatorial SST In The Elimate System

The coupled ocean-atmosphere general circulation models (CGCMs) widely used in the global climate research can provide credible simulations of fundamental properties of the climate system. However, the simulation results of these coupled models are often unsatisfactory without the inclusion of appropriate flux corrections. One of the common problems is that the simulated sea surface temperature (SST) deviates noticeably from the real observations in the tropical region. Thus the refinement of the physical process of the coupled models could improve the climate simulations essentially. The preliminary results show that the coupled models incorporated with the wave-induced vertical mixing could reduce the tropical bias. However, the exact process and factor of the improvement are not well understood yet. This study will focus on this issue by analyzing the coupled models, CCSM3 and the atmosphere-wave-ocean circulation coupled model based on the CCSM3 and wave model, simulation results to clarify the key processes and leading factors of the local changes and ocean basin-scale spatial variation in the tropical region SST by considering the wave-induced vertical mixing, and then probes the improvement mechanism of the tropical Pacific SST bias.Based on the theory of wave-induced mixing proposed by Qiao Fangli, the MASNUM atmosphere-wave-ocean circulation coupled model was established, which incorporates the MASNUM wave number spectral model and the coupled ocean-atmosphere general circulation model, CCSM3. The model is applied to study the climate research. The results compared with CCSM3 simulation are shown as follows:(1) Based on the atmosphere-wave-ocean circulation model, we designed a Nudging assimilation method of the CGCMs, and then apply the model to make experimental ENSO forecast. Compared with the CCSM3, the atmosphere-wave-ocean circulation model has the better ability of the ENSO prediction. Further, both the better initial condition of prediction and better simulation of the CGCMs also could improve the prediction ability. From the results, by considering with the wave-induced mixing effect, the bias of the initial condition and the simulation could be reduced, so the atmosphere-wave-ocean circulation model could has the better EN SO prediction.(2) One of the challenges faced by the climate model of the Community Climate System Model version 3 (CCSM3) is the spuriously simulated semi-annual cycle of the sea surface temperature (SST) in the equatorial eastern Pacific. This model bias has limited the performance of the climate simulation and prediction. Based on the surface wave-circulation coupled theory, an atmosphere-wave-ocean coupled model was developed, which incorporates the MASNUM (Marine Sciences and Numerical Modeling) wave number spectral model into CCSM3. The coupled atmosphere-wave-ocean model successfully removes the spurious semi-annual cycle simulated by the original CCSM3 and reasonably produces an SST annual cycle with warm and cold phases in April and August, respectively. The correlation between the simulated and observed SST in the equatorial eastern Pacific is improved from 0.66 to 0.93. The ocean surface layer heat budget analysis indicates that the wave-induced vertical mixing is responsible for improving the simulation of the SST seasonal cycle in the equatorial eastern Pacific.(3) Considered with the wave-induced mixing, the equatorial SST anomaly become west warm and east cold, which mean there are warm anomaly in the western ocean while cold anomaly in the eastern ocean. The process analysis of the coupled model and solo-ocean model experiments that there become cold SST anomaly due to the direct effect of the wave-induced mixing. And there become warm and cold SST anomaly through the ocean dynamical process. But the wave effect is larger due to the higher or shallower MLD (Mixed Layer Depth), so there is still cold SST anomaly in the eastern ocean. The warm and cold SST anomaly could be amplified due to the air-sea interaction. Then west warm and east cold pattern appeared. And the positive feedback is Bjernkes feedback while the SST-NetHeat is negative feedback.(4) We investigate the impact of the parallel computational uncertainty on climate simulations using the Community Climate System Model Version 3 (CCSM3). A series of sensitivity experiments have been conducted and the analyses are focused on the global and Nino3.4 sea surface temperature. It is shown that the amplitude of the deviation induced by the parallel computational uncertainty is almost the same as that of the climate system change. However, the ensemble mean method can reduce the influence and the ensemble number of 15 is enough to ignore simulated errors. For climatology, the influence can be ignored when using more than 30-year simulations calculate the climatological mean. It is also found that the parallel computational uncertainty has no effect on the simulated periods of climate variability such as ENSO. Finally, it is suggested that the influence of the parallel computational uncertainty on Coupled General Climate Models (CGCMs) could be a quality standard or a metric for developing CGCMs.