Sun and planets from a climate point of view

The Sun plays a dominant role as the gravity centre and the energy source of a planetary system. A simple estimate shows that it is mainly the distance from the Sun that determines the climate of a planet. The solar electromagnetic radiation received by a planet is very unevenly distributed on the dayside of the planet. The climate tries to equilibrate the system by transporting energy through the atmosphere and the oceans provided they exist. These quasi steady state conditions are continuously disturbed by a variety of processes and effects. Potential causes of disturbance on the Sun are the energy generation in the core, the energy transport trough the convection zone, and the energy emission from the photosphere. Well understood are the effects of the orbital parameters responsible for the total amount of solar power received by a planet and its relative distribution on the planet's surface. On a planet, many factors determine how much of the arriving energy enters the climate system and how it is distributed and ultimately reemitted back into space. On Earth, there is growing evidence that in the past solar variability played a significant role in climate chang

Predicting space climate change

The recent decline in the open magnetic flux of the Sun heralds the end of the Grand Solar Maximum (GSM) that has persisted throughout the space age, during which the largest‐fluence Solar Energetic Particle (SEP) events have been rare and Galactic Cosmic Ray (GCR) fluxes have been relatively low. In the absence of a predictive model of the solar dynamo, we here make analogue forecasts by studying past variations of solar activity in order to evaluate how long‐term change in space climate may influence the hazardous energetic particle environment of the Earth in the future. We predict the probable future variations in GCR flux, near‐Earth interplanetary magnetic field (IMF), sunspot number, and the probability of large SEP events, all deduced from cosmogenic isotope abundance changes following 24 GSMs in a 9300‐year record

Solar modulation during the Holocene

International audienceWe built a composite of three reconstructions of the solar modulation function over the Holocene. The reconstructions until 1950 are based on data from cosmogenic radionuclides and the present time (1951?2004) on neutron monitor data. Interpreting our composite as an index of solar activity, we were able to compare the current solar activity with the last 9300 years. During this time span 25 periods with similar high activity than the current period were found. That corresponds to about 15% of the time which lead to the conclusion that currently the Sun is very but not exceptionally active. Our composite has a large potential for studies dealing with solar activity like the understanding of the solar dynamo and the reconstruction of solar forcing

Cosmogenic Radionuclides as an Extension of the Neutron Monitor Era into the Past: Potential and Limitations

The cosmogenic radionuclides, 10Be, 14C and others, provide a record of the paleo-cosmic radiation that extends >10,000 years into the past. They are the only quantitative means at our disposal to study the heliosphere prior to the commencement of routine sunspot observations in the 17th century. The cosmogenic radionuclides are primarily produced by secondary neutrons generated by the galactic cosmic radiation, and can be regarded, in a sense, as providing an extrapolation of the neutron monitor era into the past. However, their characteristics are quite different from the man-made neutron monitor in several important respects: (1)they are sensitive to somewhat lower cosmic ray energies; (2)their temporal resolution is ∼1 to 2 years, being determined by the rapidity with which they are sequestered in ice, biological, or other archives; (3)the statistical precision for annual data is very poor (∼19%); however it is quite adequate (∼5% for 22-year averages) to study the large variations (±40%) that have occurred in the paleo-cosmic ray record in the past between grand solar minima and maxima. The data contains "noise” caused by local meteorological effects, and longer-term climate effects, and the use of principal component analysis to separate these "system” effects from production effects is outlined. The concentrations of 10Be decreased by a factor of two at the commencement of Holocene, the present-day "interglacial”, due to a 100% increase in the ice accumulation rates in polar regions. The use of the 10Be flux to study heliospheric properties during the last glacial is discussed briefl

10Be in Ice Cores and 14C in Tree Rings: Separation of Production and Climate Effects

Cosmogenic radionuclides are more and more used in solar activity reconstructions. However, the cosmogenic radionuclide signal also contains a climate component. It is therefore crucial to eliminate the climate information to allow a better interpretation of the reconstructed solar activity indices. In this paper the method of principal components is applied to 10Be data from two ice cores from opposite hemispheres as well as to 14C data from tree rings. The analysis shows that these records are dominated by a common signal which explains about 80% of the variance on multi decadal to multi millennial time scales, reflecting their common production rate. The second and third components are significantly different for 14C and 10Be. They are interpreted as system effects introduced by the transport of 10Be and 14C from the atmosphere where they are produced to the respective natural archives where they are stored. Principal component analysis improves significantly extraction of the production signal from the cosmogenic isotope data series, which is more appropriate for astrophysical and terrestrial studie

Geology and ground-water resources of Clayton County, Iowa

https://ir.uiowa.edu/igs_wsb/1006/thumbnail.jp

The chaotic solar cycle II. Analysis of cosmogenic 10Be data

Context. The variations of solar activity over long time intervals using a solar activity reconstruction based on the cosmogenic radionuclide 10Be measured in polar ice cores are studied. Methods. By applying methods of nonlinear dynamics, the solar activity cycle is studied using solar activity proxies that have been reaching into the past for over 9300 years. The complexity of the system is expressed by several parameters of nonlinear dynamics, such as embedding dimension or false nearest neighbors, and the method of delay coordinates is applied to the time series. We also fit a damped random walk model, which accurately describes the variability of quasars, to the solar 10Be data and investigate the corresponding power spectral distribution. The periods in the data series were searched by the Fourier and wavelet analyses. The solar activity on the long-term scale is found to be on the edge of chaotic behavior. This can explain the observed intermittent period of longer lasting solar activity minima. Filtering the data by eliminating variations below a certain period (the periods of 380 yr and 57 yr were used) yields a far more regular behavior of solar activity. A comparison between the results for the 10Be data with the 14C data shows many similarities. Both cosmogenic isotopes are strongly correlated mutually and with solar activity. Finally, we find that a series of damped random walk models provides a good fit to the 10Be data with a fixed characteristic time scale of 1000 years, which is roughly consistent with the quasi-periods found by the Fourier and wavelet analyses.Comment: 8 pages, 11 figure

The solar influence on the probability of relatively cold UK winters in the future

Recent research has suggested that relatively cold UK winters are more common when solar activity is low (Lockwood et al 2010 Environ. Res. Lett. 5 024001). Solar activity during the current sunspot minimum has fallen to levels unknown since the start of the 20th century (Lockwood 2010 Proc. R. Soc. A 466 303–29) and records of past solar variations inferred from cosmogenic isotopes (Abreu et al 2008 Geophys. Res. Lett. 35 L20109) and geomagnetic activity data (Lockwood et al 2009 Astrophys. J. 700 937–44) suggest that the current grand solar maximum is coming to an end and hence that solar activity can be expected to continue to decline. Combining cosmogenic isotope data with the long record of temperatures measured in central England, we estimate how solar change could influence the probability in the future of further UK winters that are cold, relative to the hemispheric mean temperature, if all other factors remain constant. Global warming is taken into account only through the detrending using mean hemispheric temperatures. We show that some predictive skill may be obtained by including the solar effect

Solar cycle 24: implications for energetic particles and long-term space climate change

The recent solar minimum was the longest and deepest of the space age, with the lowest average sunspot numbers for nearly a century. The Sun appears to be exiting a grand solar maximum (GSM) of activity which has persisted throughout the space age, and is headed into a significantly quieter period. Indeed, initial observations of solar cycle 24 (SC24) continue to show a relatively low heliospheric magnetic field strength and sunspot number (R), despite the average latitude of sunspots and the inclination of the heliospheric current sheet showing the rise to solar maximum is well underway. We extrapolate the available SC24 observations forward in time by assuming R will continue to follow a similar form to previous cycles, despite the end of the GSM, and predict a very weak cycle 24, with R peaking at ∼65–75 around the middle/end of 2012. Similarly, we estimate the heliospheric magnetic field strength will peak around 6nT. We estimate that average galactic cosmic ray fluxes above 1GV rigidity will be ∼10% higher in SC24 than SC23 and that the probability of a large SEP event during this cycle is 0.8, compared to 0.5 for SC23. Comparison of the SC24 R estimates with previous ends of GSMs inferred from 9300 years of cosmogenic isotope data places the current evolution of the Sun and heliosphere in the lowest 5% of cases, suggesting Maunder Minimum conditions are likely within the next 40 years

Precision measurement of the E2E2 transition strength to the 21+^+_1 state of 12^{12}C

The form factor of the electromagnetic excitation of $^{12}$C to its 2$^+_1$ state was measured at extremely low momentum transfers in an electron scattering experiment at the S-DALINAC. A combined analysis with the world form factor data results in a reduced transition strength $B(E2; 2^+_1\rightarrow 0^+_1) =7.63(19)$ e$^2$fm$^4$ with an accuracy improved to 2.5\%. In-Medium-No Core Shell Model results with interactions derived from chiral effective field theory are capable to reproduce the result. A quadrupole moment $Q(2^+_1) = 5.97(30)$ efm$^2$ can be extracted from the strict correlation with the $B((E2)$ strength emerging in the calculations.Comment: 6 pages, 6 figures, submitted to Phys. Rev.