The influence on precipitation over the eastern China of different intensities of solar radiation superimposed on different phases of PDO

Abstract:

In this study, simulations of one control experiment and four solar-only forcing experiments(spectral solar irradiance: SSI) from the Community Earth System Model Last Millennium Ensemble (CESM-LME) archive were used to investigate the influence on precipitation over the eastern China of different intensities of solar radiation superimposed on different phases of PDO during the past millennium. By analyzing the cases of strong solar radiation superimposed on the positive PDO, strong solar radiation superimposed on negative PDO, weak solar radiation superimposed on the positive PDO, and weak solar radiation superimposed on the negative PDO, the results show that in the strong solar radiation, the precipitation of positive PDO is significantly less than the negative PDO, while the precipitation of positive PDO and negative PDO were no significant difference in weak solar radiation. This phenomenon is caused by a significant reduction in precipitation of weak solar radiation superimposed on the negative PDO. In addition, when the influence of solar radiation on precipitation is not taken into account, the precipitation of positive PDO is significantly less than the negative PDO, while the precipitation of positive PDO is also significantly less than the negative PDO when considering the effects of solar radiation, but the significance is lower than the former. This phenomenon is caused by a significant reduction in precipitation of weak solar radiation superimposed on the negative PDO. The results also show that the precipitation in the case of strong solar radiation is significantly higher than that in the weak solar radiation. In positive PDO, the precipitation in the case of strong solar radiation is significantly lower than that in the case of weak solar radiation. This difference is caused by the non-significant decrease of precipitation of the positive PDO superimposed on strong solar radiation and the non-significant increase of precipitation of the positive PDO superimposed on weak solar radiation. Meanwhile, in the case of negative PDO, the precipitation in the case of strong solar radiation is more significant than that in the case of negative PDO. Therefore, both solar radiation intensity and PDO phase will affect precipitation over eastern China, and have different influences on precipitation when different intensities of solar radiation superimposed on different phases of PDO.