Modulation Of Quasi-11-year Solar Cycle On Sea Surface Temperature In The Tropical Pacific

Solar oscillation affects the formation and evolution of the Earth's climate system.The response of the tropical Pacific is still controversial in the quasi-11-year solar cycle.Based on the reanalysis data from 1870 to 2004,the sea surface temperature(SST)anomaly is the main feature on the tropical eastern Pacific in peak years of solar forcing;on this basis,24 historical experiments of the CMIP5 are evaluated the simulation responses of the tropical Pacific to peaks/valleys in solar.Finally,the control experiment and the solar-only sensitive experiment of the CESM-LME are used to verify the influence of peaks in solar.Different responses of the peak years compared to the valley years during the strong or weak solar cycle epoch in the tropical Pacific are discussed.The results are as follows:(1)In the reanalysis data,comparing peak years of solar forcing with the valley years of solar forcing,the tropical eastern Pacific tends to have a La Ni(?)a-like sea surface temperature distribution in the peak years.The possible response mechanisms include the evaporation process and the ocean dynamical thermostat process.The key response area of the evaporation process is in the subtropical Pacific and the ocean dynamical thermostat process is in the equatorial Pacific.(2)Nine CMIP5 models can simulate the La Ni(?)a-like phenomenon in the tropical Pacific during the peaks in solar,while the other fifteen models can simulate the El Ni(?)o-like phenomenon.The reason is that the cold tongue of the model whose simulation results are consistent with the reanalysis data is colder,which means that the climatic state of ocean dynamical thermostat process is stronger,with the stronger subsurface cold upwelling.It has a greater effect on the SST.The upwelling of the model with inconsistent simulation phenomena is weak.(3)The solar-only experiments of the CESM-LME are divided into the epoch of strong solar radiation with a distinct band of 8-14 years and the epoch of weak solar radiation without a distinct band.In the strong epoch,the negative anomaly of SST can also be stimulated on the tropical Pacific in the peak years of solar forcing,which is similar to the results of reanalysis data.In the weak epoch,the response of SST on the tropical Pacific has insignificant characteristics.The solar-only sensitivity experiments confirmed the effect of peaks in the solar on the negative anomalies of equatorial Pacific SST.