scholarly journals On the Interaction of Galactic Cosmic Rays with Heliospheric Shocks During Forbush Decreases

Solar Physics ◽  
2020 ◽  
Vol 295 (2) ◽  
Author(s):  
Anamarija Kirin ◽  
Bojan Vršnak ◽  
Mateja Dumbović ◽  
Bernd Heber
Keyword(s):  
Cosmic Rays ◽  
Galactic Cosmic Rays ◽  
Forbush Decreases

scholarly journals Solar activity and Earth seismicity

2021 ◽  
Vol 7 (1) ◽  
pp. 84-97
Author(s):  
Valery Yanchukovsky
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Coronal Holes ◽  
Time Lag ◽  
Galactic Cosmic Rays ◽  
Tectonic Activity ◽  
Solar Cosmic Rays ◽  
Strong Earthquakes ◽  
Forbush Decreases ◽  
The Relationship

Using the results of continuous long-term observations over 50 years (including solar cycles 20–24), we study the relationship between Earth’s seismicity and solar activity. An increase in the number of strong earthquakes on the planet occurs during the decline phase of solar activity when charged particle fluxes from high-latitude coronal holes increase, as well as during solar minimum when the intensity of galactic cosmic rays reaches a maximum. The change in the number of strong earthquakes (with magnitude 6) is considered in terms of variations in the intensity of galactic cosmic rays, Forbush decreases, and ground level enhancements in solar cosmic rays (GLE events). The number of strong earthquakes is shown to increase after Forbush decreases with a time lag from ~1 to ~6 days depending on the amplitude of Forbush decrease and after GLE events the number of strong earthquakes increases by ~8 day. In the number of strong earthquakes, a six-month variation is observed, which seems to follow the six-month variation in cosmic rays with a delay of ~1–2 months. It is surmised that the relationship between solar activity and Earth’s seismicity seems to be mediated through the modulation of galactic cosmic rays and atmospheric processes that provoke the occurrence of earthquakes in regions where the situation has already been prepared by tectonic activity.

scholarly journals Solar activity and Earth seismicity

2021 ◽  
Vol 7 (1) ◽  
pp. 67-77
Author(s):  
Valery Yanchukovsky
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Coronal Holes ◽  
Time Lag ◽  
Galactic Cosmic Rays ◽  
Tectonic Activity ◽  
Solar Cosmic Rays ◽  
Strong Earthquakes ◽  
Forbush Decreases ◽  
The Relationship

Using the results of continuous long-term observations over 50 years (including solar cycles 20–24), we study the relationship between Earth’s seismicity and solar activity. An increase in the number of strong earthquakes on the planet occurs during the decline phase of solar activity when charged particle fluxes from high-latitude coronal holes increase, as well as during solar minimum when the intensity of galactic cosmic rays reaches a maximum. The change in the number of strong earthquakes (with magnitude 6) is considered in terms of variations in the intensity of galactic cosmic rays, Forbush decreases, and ground level enhancements in solar cosmic rays (GLE events). The number of strong earthquakes is shown to increase after Forbush decreases with a time lag from ~1 to ~6 days depending on the amplitude of Forbush decrease and after GLE events the number of strong earthquakes increases by ~8 day. In the number of strong earthquakes, a six-month variation is observed, which seems to follow the six-month variation in cosmic rays with a delay of ~1–2 months. It is surmised that the relationship between solar activity and Earth’s seismicity seems to be mediated through the modulation of galactic cosmic rays and atmospheric processes that provoke the occurrence of earthquakes in regions where the situation has already been prepared by tectonic activity.

scholarly journals Model of optical response of marine aerosols to Forbush decreases

2010 ◽  
Vol 10 (6) ◽  
pp. 2765-2776 ◽  
Author(s):  
T. Bondo ◽  
M. B. Enghoff ◽  
H. Svensmark
Keyword(s):  
Cosmic Rays ◽  
Forbush Decrease ◽  
Optical Response ◽  
Galactic Cosmic Rays ◽  
Gas Production ◽  
Marine Aerosols ◽  
Forbush Decreases ◽  
Angstrom Exponent ◽  
Ångström Exponent ◽  
Ångstrom Exponent

Abstract. In order to elucidate the effect of galactic cosmic rays on cloud formation, we investigate the optical response of marine aerosols to Forbush decreases – abrupt decreases in galactic cosmic rays – by means of modeling. We vary the nucleation rate of new aerosols, in a sectional coagulation and condensation model, according to changes in ionization by the Forbush decrease. From the resulting size distribution we then calculate the aerosol optical thickness and Angstrom exponent, for the wavelength pairs 350, 450 nm and 550, 900 nm. In the cases where the output parameters from the model seem to compare best with atmospheric observations we observe, for the shorter wavelength pair, a change in Angstrom exponent, following the Forbush Decrease, of −6 to +3%. In some cases we also observe a delay in the change of Angstrom exponent, compared to the maximum of the Forbush decrease, which is caused by different sensitivities of the probing wavelengths to changes in aerosol number concentration and size. For the long wavelengths these changes are generally smaller. The types and magnitude of change is investigated for a suite of nucleation rates, condensable gas production rates, and aerosol loss rates. Furthermore we compare the model output with observations of 5 of the largest Forbush decreases after year 2000. For the 350, 450 nm pair we use AERONET data and find a comparable change in signal while the Angstrom Exponent is lower in the model than in the data, due to AERONET being mainly sampled over land. For 550, 900 nm we compare with both AERONET and MODIS and find little to no response in both model and observations. In summary our study shows that the optical properties of aerosols show a distinct response to Forbush Decreases, assuming that the nucleation of fresh aerosols is driven by ions. Shorter wavelengths seem more favorable for observing these effects and great care should be taken when analyzing observations, in order to avoid the signal being drowned out by noise.

scholarly journals Model of optical response of marine aerosols to Forbush decreases

2009 ◽  
Vol 9 (5) ◽  
pp. 22833-22863
Author(s):  
T. Bondo ◽  
M. B. Enghoff ◽  
H. Svensmark
Keyword(s):  
Cosmic Rays ◽  
Forbush Decrease ◽  
Optical Response ◽  
Galactic Cosmic Rays ◽  
Gas Production ◽  
Marine Aerosols ◽  
Forbush Decreases ◽  
Angstrom Exponent ◽  
Ångström Exponent ◽  
Ångstrom Exponent

Abstract. In order to elucidate the effect of galactic cosmic rays on cloud formation, we investigate the optical response of marine aerosols to Forbush decreases – abrupt decreases in galactic cosmic rays – by means of modeling. We vary the nucleation rate of new aerosols, in a sectional coagulation and condensation model, according to changes in ionization by the Forbush decrease. From the resulting size distribution we then calculate the aerosol optical thickness and Angstrom exponent, for the wavelength pairs 350, 450 nm and 550, 900 nm. For the shorter wavelength pair we observe a change in Angstrom exponent, following the Forbush Decrease, of −6 to +3% in the cases with atmospherically realistic output parameters. For some parameters we also observe a delay in the change of Angstrom exponent, compared to the maximum of the Forbush decrease, which is caused by different sensitivities of the probing wavelengths to changes in aerosol number concentration and size. For the long wavelengths these changes are generally smaller. The types and magnitude of change is investigated for a suite of nucleation rates, condensable gas production rates, and aerosol loss rates. Furthermore we compare the model output with observations of 5 of the largest Forbush decreases after year 2000. For the 350, 450 nm pair we use AERONET data and find a comparable change in signal while the Angstrom Exponent is lower in the model than in the data, due to AERONET being mainly sampled over land. For 550, 900 nm we compare with both AERONET and MODIS and find little to no response in both model and observations. In summary our study shows that the optical properties of aerosols show a distinct response to Forbush Decreases, assuming that the nucleation of fresh aerosols is driven by ions. Shorter wavelengths seem more favorable for observing these effects and great care should be taken when analyzing observations, in order to avoid the signal being drowned out by noise.

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