Investigating the Relationship between Climate Variables and Solar Activity: A Regression Analysis Approach

The recent publication of the summary for policy makers by Working Group I of the Intergovernmental Panel on Climate Change (IPCC) [1] has injected a renewed sense of urgency to address climate change. It is therefore timely to review the notion of preventing 'dangerous anthropogenic interference with the climate system' as put forward in the United Nations Framework Convention on Climate Change (UNFCCC). The article by Danny Harvey in this issue [2] offers a fresh perspective by rephrasing the concept of 'dangerous interference' as a problem of risk assessment. As Harvey points out, identification of 'dangerous interference' does not require us to know with certainty that future climate change will be dangerous—an impossible task given that our knowledge about future climate change includes uncertainty. Rather, it requires the assertion that interference would lead to a significant probability of dangerous climate change beyond some risk tolerance, and therefore would pose an unacceptable risk.

Carbon assimilation at low carbon dioxide levels was measured on three Oryza specics (O. sativa L. cv. Toyonishiki, O. officinalis Wall, and O. meyriana Baill.), Brassica napus L. cv. Michinokunatane and Triticum aestivum L. cv. Konosu No.25. Measurements were made at two different oxygen concentrations; 140% and 21% (atmospheric pressure). An improvement in measurement device was made for ensuring an accuracy of the meter readings. That is, a recorder with a modulator was used to enlarge the differences in the carbon dioxide concentration; two- and five-fold for carbon dioxide levels above and below carbon dioxidc compensation point (gamma), respectively. It seems that HEATH and ORCHARD (1968) and HOLMGREN and JARVIS (1967) Changed the carbon dioxide concentration at large intervals, resulting in 3 to 5 measurements below gamma. Such a few measurements would obscure the statistics of the carbon dioxide exchangc rate at low carbon dioxide levels. The changes of carbon dioxide concentration in this experiment, however, were made at intervals of about 2 or 4 ppm from 0 ppm to gamma, resulting in 7 to 14 mean values below it. As the characteristics of carbon dioxide absorption at low carbon dioxide levels, GABRIELSEN (1948) proposed the 'threshold hyPothesis' in which gamma was regarded as a threshold value below which no assimilaton occurred, while HEATH and 0RCHARD (1968) postulated the existence of a 'third process', in addition to ordinary (dark) respiration and assimilation, which could be expected to have a different balance between respiration and assimilation. They denied the adoptation of the threshold hypothesis. From the prescnt experiment in which the carbon dioxide exchange rates were traced by Changing the Carbon dioxide concentrations at very small intervals, hwever, it appeared that the rate of carbon dioxide uptake at low carbon dioxide levels and atmospheric oxygen pressure tended to decrease toward 1/2 gamma carbon dioxide level, and the carbon dioxide uptake seems to cease and only the carbon dioxide release secms to occur below it. In case of measurements at 14% oxygen concentration the situation was similar to those at 2l% oxygen concentration, but a considerable decrease of the value of gamma. Thus, the process of carbon dioxide uptake at low carbon dioxide levels seems to imply the threshold hypothesis and 1/2 gamma seems to be an approximation of the threshold value. The assimilation rate is estimated as the ratio of carbon dioxide concentration differences between ambient air and assimilation center to the sum of diffusion resistances.As an estimate of carbon dioxide levels in the assimilation center in this formula, GAASTRA (1959) proposed zero, while BIERHUIZEN and SLAYTER (1964) adopted the Practise of using gamma to estimate it. From the results mentioned above, we could propose to use 1/2 gamma as its primary approximation because the photosynthetic center would be exposed to this carbon dioxide level but not absorb it.

Counting carbon costs

The solar activity by wavelet-based multifractal analysis

External forcing on air–surface temperature: Geographical distribution of sensitive climate zones

\n Aims. The study aims to find a relationship between the rotation of the small bright coronal structures (SBCS) described by the solar rotation parameters and indices of solar activity on monthly and yearly temporal scales.\n Methods. We analyse precise measurements of the solar differential rotation determined by tracing SBCS in SOHO-EIT images and compare the derived solar rotation parameters with the status of solar activity in the period 1998 − 2006. Full-disc solar images obtained with the Extreme ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO) were used to analyse solar differential rotation determined by tracing SBCS. An automatic method to identify and track the SBCS in EIT full-disc images with a six hour cadence is applied. We performed a statistical analysis of the monthly and yearly values of solar sidereal rotation velocity parameters A and B (corresponding to the equatorial rotation velocity and the gradient of the solar differential rotation, respectively) as a function of various solar activity indices.\n Results. The dependence of the solar rotation on the phase of the solar cycle was found. It is clearly visible for the solar rotation parameter A, whilst the results are not conclusive for parameter B. The relationship between the solar rotation and activity, expressed by the monthly relative sunspot number, the smoothed monthly relative sunspot number, the yearly relative sunspot number, and the interdiurnal variability (IDV) index was investigated. The statistically significant correlation was found for the solar rotation parameter A, whilst a very low and insignificant correlation was obtained for the rotation parameter B. \n Conclusions. During the maximum of the solar cycle 23 and just after it, the equatorial solar rotation velocity was lower than in other phases of the cycle, when there was less activity. This is consistent with other observational findings, obtained by different tracers and methods.\n

Variations in the total solar irradiance (TSI) associated with solar activity have been argued to influence the Earth's climate system, in particular when solar activity deviates from the average for a substantial period. One such example is the 17th Century Maunder Minimum during which sunspot numbers were extremely low, as Earth experienced the Little Ice Age. Estimation of the TSI during that period has relied on extrapolations of correlations with sunspot numbers or even more indirectly with modulations of galactic cosmic rays. We argue that there is a minimum state of solar magnetic activity associated with a population of relatively small magnetic bipoles which persists even when sunspots are absent, and that consequently estimates of TSI for the Little Ice Age that are based on scalings with sunspot numbers are generally too low. The minimal solar activity, which measurements show to be frequently observable between active-region decay products regardless of the phase of the sunspot cycle, was approached globally after an unusually long lull in sunspot activity in 2008–2009. Therefore, the best estimate of magnetic activity, and presumably TSI, for the least-active Maunder Minimum phases appears to be provided by direct measurement in 2008–2009. The implied marginally significant decrease in TSI during the least active phases of the Maunder Minimum by 140 to 360 ppm relative to 1996 suggests that drivers other than TSI dominate Earth's long-term climate change.

Using the facilities at Heliophysics Science Division of NASA Goddard Space Flight Center, Greenbelt, MD, USA, we attempted to investigate the impact of solar magnetic activities on the climate of Wet Zone West Africa. The solar activity data namely, Sunspot Number (SSN) was obtained from the Royal Observatory of Belgium, Brussels; and Geomagnetic aa-index was obtained from World Data Center, Kyoto, Japan. Surface Air Temperature (SAT) and Rainfall data [for Port Harcourt in Nigeria and Abidjan in Cote D’Ivoire] were obtained from the HadCRUT-4 project of Climate Research Unit of University of East Anglia, United Kingdom. Firstly, we carried out Time Series Analysis of SSN and Geomagnetic aa-index spanning from 1950 to 2016. Secondly, we performed Regression Analysis on both solar activity data and climate variables to estimate the impact of solar magnetic activity on the Wet Zone West African climate. The Time Series Analysis showed that SSN variation was in-phase with Geomagnetic aa-index in all the solar cycles studied. Thus, Geomagnetic aa-index can be used as a proxy for studying solar magnetic activities. Performance of Regression Analysis showed that SSN regressed on SAT and Rainfall amounted to an average of 0.49 and 0.02% respectively throughout Solar Cycles 22–24. Furthermore, a regression of Geomagnetic aa-index on SAT and Rainfall yielded an average of 0.145 and 0.125% respectively. Our models showed that the variability of SAT and Rainfall in Wet Zone West Africa during Solar Cycles 22–24 are far less than 1%. Hence, the influence of SSN and Geomagnetic aa-index on SAT and Rainfall is less than 1%; and could cause ‘very small’ effect. These weak impacts are proofs that the variability of SAT and Rainfall were most probably not effected by SSN and Geomagnetic aa-index. Consequently, the variability of SAT and Rainfall in Wet Zone West Africa could not be attributed to SSN and Geomagnetic aa-index. We therefore, attempt to conclude that climate variability in Wet Zone West Africa is most probably not driven by solar magnetic activity, but could be attributed to anthropogenic activities.

The oxygen production of a photosynthetic gas exchanger containing Chlorella pyrenoidosa (1% packed cell volume) was measured when various concentrations of carbon dioxide were present within the culture unit. The internal carbon dioxide concentrations were obtained by manipulating the entrance gas concentration and the flow rate. Carbon dioxide percentages were monitored by means of electrodes placed directly in the nutrient medium. The concentration of carbon dioxide in the nutrient medium which produced maximal photosynthesis was in the range of 1.5 to 2.5% by volume. Results were unaffected by either the level of carbon dioxide in the entrance gas or the rate of gas flow. Entrance gases containing 2% carbon dioxide flowing at 320 ml/min, 3% carbon dioxide at 135 ml/min, and 4% carbon dioxide at 55 ml/min yielded optimal carbon dioxide concentrations in the particular unit studied. By using carbon dioxide electrodes implanted directly in the gas exchanger to optimize the carbon dioxide concentration throughout the culture medium, it should be possible to design more efficient large-scale units.

Evidence of solar signals in tree rings of Smith fir from Sygera Mountain in southeast Tibet

Solar activities have obvious effects on earth＇s climate. Many scientists have studied the relationship between solar activities and climate change, and a lot of papers have been published in this field. The relative sunspot numbers is an important factor in the research of solar activities. Wavelet transform is a fine method to analyze time serials periods. By using different data, the periods are different. In the past time, many scholars had analyzed solar activities by others statistical methods, found that changes of solar activity have periods of 5-6 years, 11 years, 22 years, 80-100 years, and so on. The periods are so disunity that they can＇t be better used to forecast change trend of solar activities. In this paper, being applied to analysis of solar activities, the wavelet transform method was introduced to analyze periods change, and found some meaningful results. The relative sunspot numbers change with periods of 10.7 year and 101 year. The 10.7 year period is remarkable, and it＇s amplitude varies with time. In 1935 to 2000, the amplitude of 10.7 year period are especially distinct. The solar activities exist strong or weak phases. Abrupt change occurred in 1950 year, and solar activities became stronger since 1950. It is predicled that the solar activity will be weaker in the near future.

Knowing what ancient variations in the concentration of carbon dioxide, indicative of climatic change, in the earth's atmosphere have occurred, can help scientists predict what lies in store for the next century as pollution drives carbon dioxide levels up. A new technique offers hope for tracing carbon dioxide levels back in time. Paleobotanists report that morphological studies of fossil leaves can offer a clue. Research on vegetation growing in greenhouse has shown that the density of stomata depends on the atmospheric concentration of carbon dioxide, a relationship found also outside the greenhouse. Palobotanists have developed a stomatal index to evaluate ancient leaves, and then have gone further by devising an equation relating stomata indexes to carbon dioxide concentrations of ancient times. This technique suggests that gas levels 10 million years ago averaged around 370 ppm, then dropped to 280 ppm during a cool spell, later rising back to 370 ppm. As with other techniques, this has some critisms, mentioned in the article, but it does add to the information available for evaluating future climatic change.

There is compelling evidence that warming of the climate system due to human influence is taking place. The mechanisms for these processes include increasing levels of greenhouse gases (GHGs) in the atmosphere. In May 2013, carbon dioxide levels in the atmosphere exceeded 400 ppm for the first time in several hundred millennia. Levels of carbon dioxide in the remote atmosphere have increased by 0.28 and 2.93 parts per million (ppm) per year since 1960. Ongoing increases in levels of GHGs can be expected to result in a rise in global temperatures, which could trigger a wide range of risk scenarios. A level of 450 ppm is considered to be the atmospheric concentration of carbon dioxide at which temperature change can still be limited to 2 °C. This is a benchmark of climate change specified so as to limit the dangerous effects of climate change. The international community has initiated a series of programmes to address GHG emissions, underpinned by a significant effort to develop robust emission inventories: however, these initiatives have had limited success in limiting the rising trends in GHG emissions. The key issues encountered during these programmes include: population and economic growth; scientific credibility; political priorities; outsourcing of emissions; and difficulties in implementing renewable energy technologies. In this context, the scientific community has an ongoing role to produce data and analysis to link individual, corporate and state actions and policies to evaluations of GHG emissions, and analysis of evidence for changes in the global climate. The scientific and policy communities should continue to engage with the public, to provide reliable information about the vitally important issues associated with global climate change. Public support for positive action and investment to mitigate climate change is essential to support the decisions which will need to be taken in the coming decades.

We propose using multiple regression to create a statistical model for describing climate change under the influence of specified climate-forming factors. This model provides not only estimates of the temporal evolution of global temperature, but also a set of corresponding confidence intervals with a high level of statistical significance (probability). Eliminating the linear trend of climatic temperature series (CRUTEM) and atmospheric CO2 concentration allows an objective quantitative assessment of the impact of natural factors on climate change. The global CRUTEM temperature responds quasi-synchronously to the fluctuations in the average surface temperature of the North Atlantic (AMO index); however, to changes in solar activity (Wolf numbers), it does so with a delay of approximately 15 years. The linear trend of increasing CO2 concentration in the atmosphere explains almost all the interannual variability and reflects the linear trend of global temperature, but covers only part of its interannual variability.

We carried out wavelet and correlation analysis in the range of periods of 20–70 years of the following instrumental data series: the number of sunspots in 1700–2020, on the one hand, and the average global temperature and Earth rotation rate, as well as the and components of the geomagnetic field measured in magnetic observatories starting from the end of the 19th century, on the other hand. It was obtained that over the past ~150–170 years, ~40-year and ~20-year variations have been observed in the wavelet spectra. In all spectra of geophysical data at this time, 60–70-year variation dominates, in addition, fluctuations with periods from ~20 to ~40 years appear in different time intervals. The rotation rate correlates with the temperature at the level of 0.8 and both processes are almost the same in phase. Their main common period is 69 years. The identified ~60–70-year variations in the spectra of the geomagnetic field are caused by changes in internal sources in the Earth’s liquid core. Our results suggest that the influence of solar activity does not manifest itself in ~60–70 year changes in the magnetic field components, as well as in the temperature of the Earth. At the same time, solar activity appears to be able to contribute directly to temperature changes with periods of ~35 years; the correlation coefficient of the and temperature spectra in this period range was ≈0.5.