The study of the physical processes that drive the variability of the Earth's climate system is one of the most fascinating and challenging topics of research today. Perhaps the largest uncertainties in our ability to predict climate change are the cloud formation process and the interaction of clouds with radiation. Here we show that in the southern Pacific Ocean cloud effects on the net radiative flux in the atmosphere are related to the intensity of the Earth's magnetic field through lower atmosphere cosmic ray effects. In the inner region of the Southern Hemisphere Magnetic Anomaly (SHMA) it is observed a cooling effect of approximately 18 W/m2 while in the outer region it is observed a heating effect of approximately 20 W/m2. The variability in the inner region of the SHMA of the net radiative flux is correlated to galactic cosmic rays (GCRs) flux observed in Huancayo, Peru (r = 0.73). It is also observed in the correlation map that the correlation increases in the inner region of the SHMA. The geomagnetic modulation of cloud effects in the net radiative flux in the atmosphere in the SHMA is, therefore, unambiguously due to GCRs and/or highly energetic solar proton particles effects.

[1] The influence of solar variability into the lower atmospheric regions has been suggested on different atmospheric parameters in different time scales. However, a plausible mechanism to explain these observations remains unclear. Although it is widely accepted that the climate change over the past 50 years is attributed to human influence, we present the case that local climate change in the tropical Pacific may be due to changes in the Earth's magnetic field strength. The changes in the tropical Pacific circulation have been observed during the last 50 years, and they are attributed to the increase of the global surface temperature. However, a geomagnetic modulation of the net radiative flux in the southern tropical Pacific was recently suggested. Moreover, comparisons of long-term reconstructions of the Northern Hemisphere surface temperature and solar activity proxies indicated that the existence of a geomagnetic signal in climate data would support a direct link between solar variability and their effects on climate. Here we show that in the tropical Pacific the sea-level pressure, which is a component of the Walker circulation, could be related to the magnetospheric, ionospheric, and upper-atmosphere processes which may propagate downward to the lower atmosphere. Furthermore, we show that the changes in sea-level pressure and the Walker circulation are correlated to the westward drift of the magnetic anomaly. We compare the region averaged monthly values of the sea-level pressure in the tropical Pacific with those of the magnetic field intensity near the surface for the last 50 years. We find that the sea-level pressure in the tropical Pacific is increasing as the magnetic field intensity is decreasing. The correlation coefficient of the sea-level pressure 36-month running means versus the magnetic field intensity is 0.96. We anticipate our investigation to be a starting point for a more sophisticated investigation of the coupling between the space weather processes and lower atmosphere and ocean dynamics.Citation: Vieira, L. E. A., L. A. da Silva, and F. L. Guarnieri (2008), Are changes of the geomagnetic field intensity related to changes of the tropical Pacific sea-level pressure during the last 50 years?,

Abstract. This work presents an analysis of the ionospheric responses to the solar eclipse that occurred on December 14, 2020, over the Brazilian sector. This event partially covers the south of Brazil, providing an excellent opportunity to study the modifications in the peculiarities that occur in this sector, as the Equatorial Ionization Anomaly (EIA). Therefore, we used the Digisonde data available in this period for two sites, Campo Grande (CG, 20.47° S, 54.60° W, dip ∼23° S) and Cachoeira Paulista (CXP, 22.70° S, 45.01° W, dip ∼35° S), assessing the E, and F regions, and Es layer behaviors. Additionally, a numerical model (MIRE, Portuguese acronym for E Region Ionospheric Model) is used to analyze the E layer dynamics modification around these times. The results show the F1 region disappearance and an apparent electronic density reduction in the E region during the solar eclipse. We also analyzed the total electron content (TEC) maps from the Global Navigation Satellite System (GNSS) that indicate a weakness in the EIA. On the other hand, we observe the rise of the Es layer electron density, which is related to the gravity waves strengthened during solar eclipse events. Finally, our results lead to a better understanding of the restructuring mechanisms in the ionosphere at low latitudes during the solar eclipse events, even though they only partially reached the studied regions.

Abstract. The effects of changes in the solar radiative emission on ozone levels in the stratosphere have been considered as a candidate to explain the link between solar activity and its effects on the climate. As ozone absorbs electromagnetic radiation, changes in ozone concentrations alter Earth's radiative balance by modifying both incoming solar radiation and outgoing radiation. In this way, ozone controls solar energy deposition in the stratosphere and its variations alter the thermal structure of the stratosphere. These changes are assumed to propagate downward through a chain of feedbacks involving thermal and dynamical processes. The effects of high energy particle precipitation on mesospheric and stratospheric ozone have also been investigated. However, while the effects of high energy particle precipitation on ozone distribution in the auroral region has been investigated during the last decades, little is known about the role of the high energy particle precipitation on the stratospheric composition and thermal structure in the tropical/subtropical region. Here we show that the spatial distribution of the lower stratosphere temperature is affected by the presence of the southern hemisphere magnetic anomaly. We found that during the austral winter and spring, in the subtropical region (below 30 deg S), the reduction of the lower stratosphere temperature occurs systematically in the magnetic anomaly area. This result is consistent with the observations that in the southern hemisphere subtropical region the energy of precipitating particles is deposited lower in altitude in regions with weaker magnetic field intensity.