The Mansurov effect is related to the interplanetary magnetic field (IMF) and its ability to modulate the global electric circuit, which is further hypothesized to impact the polar troposphere through cloud generation processes. We investigate the connection between IMF By-component and polar surface pressure by using daily ERA5 reanalysis for geopotential height since 1980. Previous studies produce a 27-day cyclic response during solar cycle 23 which appears to be significant according to conventional statistical tests. However, we show here that when statistical tests appropriate for strongly autocorrelated variables are applied, there is a fairly high probability of obtaining the cyclic response and associated correlation merely by chance. Our results also show that data from three other solar cycles, produce similar cyclic responses as during solar cycle 23, but with seemingly random offset in respect to timing of the signal. By generating random normally distributed noise with different levels of temporal autocorrelation, and using the real IMF By-time series as forcing, we show that the methods applied to support the Mansurov hypothesis up to now, are highly susceptible to random chance, as cyclic patterns always arise as artefacts of the methods. Potential non-stationary behavior of the Mansurov effect makes it difficult to achieve solid statistical significance on decadal time scales. We suggest more research on, e.g., seasonal dependence of the Mansurov effect to understand better potential IMF effects in the atmosphere.

<p>Evidence are pointing to two potential links between solar wind forcing and atmospheric dynamics in polar regions. The chemical link follows from energetic particle precipitation (EPP) ionizing the higher atmosphere, leading to a production of nitrogen and hydrogen oxides (NOx and HOx), which later on participate in ozone destruction. This can lead to changes in the radiative balance of the atmosphere, followed by related changes in winds. The physical link is related to the interplanetary magnetic field (IMF) and its ability to modulate the global electric circuit (GEC), with a hypothesized link between changes in the GEC and polar tropospheric dynamics through cloud generation processes. By use of ERA-5 reanalysis data and OMNI near Earth solar wind magnetic field and plasma parameter data, we investigate these links with a multiple correlation analysis. Internal atmospheric variability is excluded before the analysis. Time period of the data is 1979-2018. Results concerning the chemical link show a significant negative correlation between EPP (geomagnetic activity index Ap used as a proxy) and pressure anomalies in the local winter inside the polar vortex. The anomaly, starting in the stratosphere, extends downwards to the surface in a matter of days. The results indicate a greater response in the north compared to the south. For the physical link, a significant correlation is seen between the IMF horizontal (By) component and lower tropospheric pressure in the south for certain months in local summer. There seems to be no correlation between the two indices, Ap and By, indicating that these mechanisms operate individually without aliasing between the two. These results imply that solar wind variability can potentially impact polar atmospheric dynamics during specific seasons in different ways. This can enhance our understanding on solar related atmospheric effects.</p>

Recently, observational and re‐analysis studies have outlined potentially enhanced influence of Energetic Particle Precipitation (EPP) either at times preceding Sudden Stratospheric Warmings (SSW) or when the distribution of planetary wave activity is suitable. In addition, significant correlations have been found between EPP and the occurrence rate of SSWs when the phases of the Quasi‐Biennial Oscillation (QBO) are taken into account. Here we study the influence of EPP during disturbed stratospheric polar vortex conditions using chemistry‐climate model SOCOL‐MPIOM3 over the 20th century. When classifying disturbed conditions, the definition of minor SSWs are utilized along with a temperature gradient (day‐to‐day variations) criteria at 90°N and 10 hPa acting as a measure of the strength of the events. We find no influence of EPP on the occurrence rate of disturbed conditions over the last 100 year period. However, conditions preceding and during the disturbances are significantly different when EPP forcing is included into the model. This is especially true for stratospheric disturbances occurring in February. Furthermore, there is a clear tendency that the EPP effect becomes more notable after the 1950s. Our results imply that EPP forcing could be important for the stratospheric conditions during winter and that pre‐conditioning forced by atmospheric disturbances are an important factor when considering how the mechanism operates.

<p>The Mansurov Effect is related to the interplanetary magnetic field (IMF) and its ability to modulate the global electric circuit, which is further hypothesized to impact the polar troposphere through cloud generation processes. In this paper we investigate the connection between IMF By-component and polar surface pressure by using daily ERA5 reanalysis for geopotential height since 1980. Previous studies have shown to produce a significant 27-day cyclic response during solar cycle 23. However, when appropriate statistical tests are applied, the correlation is not significant at the 95% level. Our results also show that data from three other solar cycles, which have not been investigated before, produce similar cyclic responses as during solar cycle 23, but with seemingly random offset in the timing of the signal. We examine the origin of the cyclic pattern occurring in the super epoch/lead lag regression methods commonly used to support the Mansurov hypothesis in all recent papers, as well as other phenomena in this community. By generating random normally distributed noise with different levels of temporal autocorrelation, and using the real IMF By-index as forcing, we show that the methods applied to support the Mansurov hypothesis up to now, are highly susceptible, as cyclic patterns always occurs as artefacts of the methods. This, in addition to the lack of significance, suggests that there is no adequate evidence in support of the Mansurov Effect.</p>

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