Middle atmosphere response to the solar cycle in irradiance and ionizing particle precipitation

Abstract. The impact of NOx and HOx production by three types of energetic particle precipitation (EPP), auroral zone medium and high energy electrons, solar proton events and galactic cosmic rays on the middle atmosphere is examined using a chemistry climate model. This process study uses ensemble simulations forced by transient EPP derived from observations with one-year repeating sea surface temperatures and fixed chemical boundary conditions for cases with and without solar cycle in irradiance. Our model results show a wintertime polar stratosphere ozone reduction of between 3 and 10 % in agreement with previous studies. EPP is found to modulate the radiative solar cycle effect in the middle atmosphere in a significant way, bringing temperature and ozone variations closer to observed patterns. The Southern Hemisphere polar vortex undergoes an intensification from solar minimum to solar maximum instead of a weakening. This changes the solar cycle variation of the Brewer-Dobson circulation, with a weakening during solar maxima compared to solar minima. In response, the tropical tropopause temperature manifests a statistically significant solar cycle variation resulting in about 4 % more water vapour transported into the lower tropical stratosphere during solar maxima compared to solar minima. This has implications for surface temperature variation due to the associated change in radiative forcing.

Download Full-text

Middle atmosphere response to the solar cycle in irradiance and ionizing particle precipitation

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-24853-2010 ◽

2010 ◽

Vol 10 (10) ◽

pp. 24853-24917 ◽

Cited By ~ 1

Author(s):

K. Semeniuk ◽

V. I. Fomichev ◽

J. C. McConnell ◽

C. Fu ◽

S. M. L. Melo ◽

...

Keyword(s):

Solar Cycle ◽

Radiative Forcing ◽

Climate Model ◽

Middle Atmosphere ◽

Polar Vortex ◽

Galactic Cosmic Rays ◽

Particle Precipitation ◽

Solar Cycle Variation ◽

Cycle Variation ◽

The Impact

Abstract. The impact of NOx and HOx production by three types of energetic particle precipitation (EPP), aurora, solar proton events and galactic cosmic rays is examined using a chemistry climate model. Ensemble simulations forced by transient EPP derived from observations with one-year repeating sea surface temperatures and fixed chemical boundary conditions were conducted for cases with and without solar cycle in irradiance. Our model results show a wintertime polar stratosphere ozone reduction of between 3 and 10% in agreement with previous studies. EPP is found to modulate the radiative solar cycle effect in the middle atmosphere in a significant way, bringing temperature and ozone variations closer to observed patterns. The Southern Hemisphere polar vortex undergoes an intensification from solar minimum to solar maximum instead of a weakening. This changes the solar cycle variation of the Brewer-Dobson circulation, with a weakening during solar maxima compared to solar minima. In response, the tropical tropopause temperature manifests a statistically significant solar cycle variation resulting in about 4% more water vapour transported into the lower tropical stratosphere during solar maxima compared to solar minima. This has implications for surface temperature variation due to the associated change in radiative forcing.

Download Full-text

Probing the heliosphere with the directional anisotropy of galactic cosmic-ray intensity

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312004826 ◽

2011 ◽

Vol 7 (S286) ◽

pp. 185-194 ◽

Cited By ~ 1

Author(s):

Kazuoki Munakata

Keyword(s):

Solar Cycle ◽

Magnetic Structure ◽

Large Scale ◽

Cosmic Ray ◽

High Energy ◽

Galactic Cosmic Rays ◽

Spatial Gradient ◽

Solar Cycle Variation ◽

Directional Anisotropy ◽

Cycle Variation

AbstractBecause of the large detector volume that can be deployed, ground-based detectors remain state-of-the-art instrumentation for measuring high-energy galactic cosmic-rays (GCRs). This paper demonstrates how useful information can be derived from observations of the directional anisotropy of the high-energy GCR intensity, introducing the most recent results obtained from the ground-based observations. The anisotropy observed with the global muon detector network (GMDN) provides us with a unique information of the spatial gradient of the GCR density which reflects the large-scale magnetic structure in the heliosphere. The solar cycle variation of the gradient gives an important information on the GCR transport in the heliosphere, while the short-term variation of the gradient enables us to deduce the large-scale geometry of the magnetic flux rope and the interplanetary coronal mass ejection (ICME). Real-time monitoring of the precursory anisotropy which has often been observed at the Earth preceding the arrival of the ICME accompanied by a strong shock may provide us with useful tools for forecasting the space weather with a long lead time. The solar cycle variation of the Sun's shadow observed in the TeV GCR intensity is also useful for probing the large-scale magnetic structure of the solar corona.

Download Full-text

Atmospheric changes caused by galactic cosmic rays over the period 1960–2010

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-5853-2016 ◽

2016 ◽

Vol 16 (9) ◽

pp. 5853-5866 ◽

Cited By ~ 17

Author(s):

Charles H. Jackman ◽

Daniel R. Marsh ◽

Douglas E. Kinnison ◽

Christopher J. Mertens ◽

Eric L. Fleming

Keyword(s):

Cosmic Rays ◽

Climate Model ◽

Cosmic Ray ◽

Galactic Cosmic Rays ◽

Sulfate Aerosol ◽

Solar Cycle Variation ◽

Aerosol Loading ◽

Ion Production ◽

Column Ozone ◽

The Impact

Abstract. The Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM) and the Goddard Space Flight Center two-dimensional (GSFC 2-D) models are used to investigate the effect of galactic cosmic rays (GCRs) on the atmosphere over the 1960–2010 time period. The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) computation of the GCR-caused ionization rates are used in these simulations. GCR-caused maximum NOx increases of 4–15 % are computed in the Southern polar troposphere with associated ozone increases of 1–2 %. NOx increases of ∼ 1–6 % are calculated for the lower stratosphere with associated ozone decreases of 0.2–1 %. The primary impact of GCRs on ozone was due to their production of NOx. The impact of GCRs varies with the atmospheric chlorine loading, sulfate aerosol loading, and solar cycle variation. Because of the interference between the NOx and ClOx ozone loss cycles (e.g., the ClO + NO2+ M  →  ClONO2+ M reaction) and the change in the importance of ClOx in the ozone budget, GCRs cause larger atmospheric impacts with less chlorine loading. GCRs also cause larger atmospheric impacts with less sulfate aerosol loading and for years closer to solar minimum. GCR-caused decreases of annual average global total ozone (AAGTO) were computed to be 0.2 % or less with GCR-caused column ozone increases between 1000 and 100 hPa of 0.08 % or less and GCR-caused column ozone decreases between 100 and 1 hPa of 0.23 % or less. Although these computed ozone impacts are small, GCRs provide a natural influence on ozone and need to be quantified over long time periods. This result serves as a lower limit because of the use of the ionization model NAIRAS/HZETRN which underestimates the ion production by neglecting electromagnetic and muon branches of the cosmic ray induced cascade. This will be corrected in future works.

Download Full-text

Atmospheric changes caused by galactic cosmic rays over the period 1960–2010

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-33931-2015 ◽

2015 ◽

Vol 15 (23) ◽

pp. 33931-33966 ◽

Cited By ~ 5

Author(s):

C. H. Jackman ◽

D. R. Marsh ◽

D. E. Kinnison ◽

C. J. Mertens ◽

E. L. Fleming

Keyword(s):

Cosmic Rays ◽

Climate Model ◽

Galactic Cosmic Rays ◽

Sulfate Aerosol ◽

Solar Cycle Variation ◽

Aerosol Loading ◽

Long Time ◽

Column Ozone ◽

Atmospheric Changes ◽

The Impact

Abstract. The Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM) and the Goddard Space Flight Center two-dimensional (GSFC 2-D) models are used to investigate the effect of galactic cosmic rays (GCRs) on the atmosphere over the 1960–2010 time period. The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) computation of the GCR-caused ionization rates are used in these simulations. GCR-caused maximum NOx increases of 4–15 % are computed in the Southern polar troposphere with associated ozone increases of 1–2 %. NOx increases of ∼ 1–6 % are calculated for the lower stratosphere with associated ozone decreases of 0.2–1 %. The primary impact of GCRs on ozone was due to their production of NOx. The impact of GCRs varies with the atmospheric chlorine loading, sulfate aerosol loading, and solar cycle variation. Because of the interference between the NOx and ClOx ozone loss cycles (e.g., the ClO + NO2 + M → ClONO2 + M reaction) and the change in the importance of ClOx in the ozone budget, GCRs cause larger atmospheric impacts with less chlorine loading. GCRs also cause larger atmospheric impacts with less sulfate aerosol loading and for years closer to solar minimum. GCR-caused decreases of annual average global total ozone (AAGTO) were computed to be 0.2 % or less with GCR-caused tropospheric column ozone increases of 0.08 % or less and GCR-caused stratospheric column ozone decreases of 0.23 % or less. Although these computed ozone impacts are small, GCRs provide a natural influence on ozone and need to be quantified over long time periods.

Download Full-text