The Statistic And Numerical Simulation Study On The Character Of Solar Wind Impacting On Northern Hemispheric Circulation In Winter

Solar wind induced climate change is considered as one of the important pathways to amplify the solar activity signal in the climate system.The atmospheric circulation anomaly in the middle and high latitudes,especially the North Atlantic Oscillation(NAO),is closely related to the solar activity,and is one of the key sensitive areas where solar activity affects climate through space weather mechanism.This research focus on the pathway of solar wind driven chemistry effect of energetic electrons on climate change,and employed multiple linear regression method to analyze the boreal winter atmospheric circulation,NAO and sea surface temperature(SST)response to the solar wind speed(SWS).Then the possible propagation pathways and mechanisms of solar wind signal in the climate system were discussed.Furthermore,based on the particle forcing data of the solar forcing for the sixth Coupled Model Intercomparison Project(CMIP6),we used a coupled chemistry-climate model,SOCOL3.0,to simulate the effect of energetic particle precipitation(EPP)on the climate,and evaluated the extent and process of the space particle forcing affecting climate.The main conclusions are as follows:(1)Multiple linear regression analysis of the boreal winter atmospheric circulation,NAO and SST on the factors including SWS,sunspot numbers,volcanic,ENSO,Quasi Biennial Oscillation(QBO)and trend term showed that the SWS had a more significant impact on the NAO and related atmospheric circulation and SST than other external forcing factors or atmospheric internal factors.The influence of solar wind on planetary wave activity plays an important role in the poleward and downward propagation of SWS signal and the coupling of stratosphere and troposphere.(2)Based on the particle forcing input of the solar forcing for CMIP6,SOCOL3.0was used to simulate and evaluate the chemical effects of solar wind induced low energy electrons(LEE)and middle energy electrons(MEE)precipitation.The results pointed out that the upper boundary condition setting of NO_x([N]+[NO]+[NO2])flux of LEE is of decisive significance.In this paper,the simulation experiments with the LEE parameterization scheme recommended by CMIP6 showed that the NO_x generated by LEE not only destroy a lot of ozone in the mesosphere,but also can be transported to the stratosphere through EPP indirect effect to affect stratospheric ozone.(3)The simulation results showed that adding LEE and MEE into the model could improve the simulation accuracy of NO_x concentration,and improve the simulation of temperature in boreal winter and southern spring.(4)Including the LEE and MEE to the model,the examined responses of winter temperature and zonal wind in the Northern Hemisphere to SWS in the ERA-Interim data can be well reproduced.This further provided strong evidence for the chemical-dynamical mechanism that may affect NAO.It also indicates that a climate model including a complete description of EPP process is necessary to improve the accuracy of climate simulation.(5)There are two possible pathways for solar wind to affect boreal winter climate and NAO:one is the chemical-dynamical mechanism caused by the EPP;the other is the mechanism of space weather-atmospheric electric-cloud microphysics.According to the results of this paper,the chemical-dynamical mechanism induced by high energetic electrons can partially explain the relationship between SWS and NAO and associated SST in the observational data,and these results also indicate that atmospheric electrical effect may also play an important role in the climate system,especially on the lower tropospheric atmospheric circulation anomaly.