SOLAR INFLUENCES ON CLIMATE Gray, L. J.; Beer, J.; Geller, M. ...
Reviews of geophysics (1985),
December 2010, Letnik:
48, Številka:
4
Journal Article
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Understanding the influence of solar variability on the Earth's climate requires knowledge of solar variability, solar‐terrestrial interactions, and the mechanisms determining the response of the ...Earth's climate system. We provide a summary of our current understanding in each of these three areas. Observations and mechanisms for the Sun's variability are described, including solar irradiance variations on both decadal and centennial time scales and their relation to galactic cosmic rays. Corresponding observations of variations of the Earth's climate on associated time scales are described, including variations in ozone, temperatures, winds, clouds, precipitation, and regional modes of variability such as the monsoons and the North Atlantic Oscillation. A discussion of the available solar and climate proxies is provided. Mechanisms proposed to explain these climate observations are described, including the effects of variations in solar irradiance and of charged particles. Finally, the contributions of solar variations to recent observations of global climate change are discussed.
The 11 year solar‐cycle component of climate variability is assessed in historical simulations of models taken from the Coupled Model Intercomparison Project, phase 5 (CMIP‐5). Multiple linear ...regression is applied to estimate the zonal temperature, wind and annular mode responses to a typical solar cycle, with a focus on both the stratosphere and the stratospheric influence on the surface over the period ∼1850–2005. The analysis is performed on all CMIP‐5 models but focuses on the 13 CMIP‐5 models that resolve the stratosphere (high‐top models) and compares the simulated solar cycle signature with reanalysis data. The 11 year solar cycle component of climate variability is found to be weaker in terms of magnitude and latitudinal gradient around the stratopause in the models than in the reanalysis. The peak in temperature in the lower equatorial stratosphere (∼70 hPa) reported in some studies is found in the models to depend on the length of the analysis period, with the last 30 years yielding the strongest response.
A modification of the Polar Jet Oscillation (PJO) in response to the 11 year solar cycle is not robust across all models, but is more apparent in models with high spectral resolution in the short‐wave region. The PJO evolution is slower in these models, leading to a stronger response during February, whereas observations indicate it to be weaker. In early winter, the magnitude of the modelled response is more consistent with observations when only data from 1979–2005 are considered. The observed North Pacific high‐pressure surface response during the solar maximum is only simulated in some models, for which there are no distinguishing model characteristics. The lagged North Atlantic surface response is reproduced in both high‐ and low‐top models, but is more prevalent in the former. In both cases, the magnitude of the response is generally lower than in observations.
Tobacco control advocates and researchers face powerful opponents who go to great lengths to protect their interests. While threats and attacks are documented in the grey literature, research into ...intimidation remains scarce. Building on previous exploratory research, this study seeks to offer in-depth insights into experiences of intimidation in the global tobacco control community. Using qualitative description, we conducted a focus group and semi-structured interviews with tobacco control advocates and researchers to explore their experiences, including forms of, and responses to, intimidation, and ways forward. Data were analysed using qualitative content analysis. Twenty-nine individuals from across the globe participated in the study. They reported several forms of intimidation including attacks in the media; online harassment; legal threats; non-legal threats, including death threats; Freedom of Information requests; perceived or actual surveillance; as well as burglary and theft. Responses included non-action (i.e. ignoring attacks); withdrawal (i.e. abandoning a project, area or field); defensive adaptation, for example through self-censorship; and offensive measures, including exposing attacks or filing complaints. Responses were shaped by several factors, including type and level of support from within internal and external networks; as well as an individual's mindset, skills and experiences; and state-civil society relations. Participants suggested several measures that could help address intimidation: 1) report and monitor intimidation; 2) (better) prepare individuals through awareness raising and training (e.g. IT security, legal); 3) support those in need through legal advice, a peer-support network and involvement in response; and 4) look beyond tobacco control to learn and build connections. Intimidation is a significant challenge to tobacco control that needs urgent attention. This study suggests measures to address intimidation that require commitment from, and collaboration amongst, multiple actors including governments, international organisations, funders, researchers and civil society. Moreover, collective action beyond tobacco control is needed to not only manage but move beyond intimidation.
The surface response to the 11 year solar cycle is assessed in ensemble simulations of the twentieth century climate performed in the framework of the fifth phase of the Coupled Model ...Inter‐Comparison Project (CMIP5). A lead/lag multiple linear regression analysis identifies a multi‐model mean (MMM) global mean surface warming of about 0.07 K, lagging the solar cycle by 1–2 years on average. The anomalous warming penetrates to approximately the first 80–100 m depth in the ocean. Solar signals in the troposphere show a similar time lag of 1–2 years and the strongest MMM warming is simulated in the Tropics above 300 hPa. At the surface, the MMM response in a subset of models that show statistically significant global mean warming (CMIP5‐SIG95) is characterized by an anomalous warming in the west equatorial Pacific Ocean and the Arctic, at 1–2 years after solar maximum. The Arctic warming is twice as strong as the global mean response and appears in the winter months only. The surface warming in the equatorial Pacific Ocean is related to dynamical/thermodynamical processes. Different increase rates of global mean precipitation and atmospheric water vapour in response to a warmer surface lead to a weaker Walker circulation and anomalous westerly winds over the equatorial Pacific in the years following the solar maximum. Owing to atmosphere–ocean coupling, the anomalous westerly winds cool the subsurface and warm the surface in the western equatorial Pacific by ∼0.14 K. The CMIP5‐SIG95 MMM surface warming in the equatorial Pacific and Arctic is weak but qualitatively similar compared with solar signals in the HadCRUT4 dataset.
The NCAR Whole Atmosphere Community Climate Model, version 3 (WACCM3), is used to study the atmospheric response from the surface to the lower thermosphere to changes in solar and geomagnetic forcing ...over the 11‐year solar cycle. WACCM3 is a general circulation model that incorporates interactive chemistry that solves for both neutral and ion species. Energy inputs include solar radiation and energetic particles, which vary significantly over the solar cycle. This paper presents a comparison of simulations for solar cycle maximum and solar cycle minimum conditions. Changes in composition and dynamical variables are clearly seen in the middle and upper atmosphere, and these in turn affect terms in the energy budget. Generally good agreement is found between the model response and that derived from satellite observations, although significant differences remain. A small but statistically significant response is predicted in tropospheric winds and temperatures which is consistent with signals observed in reanalysis data sets.
A multiple linear regression statistical method is applied to model data taken from the Coupled Model Intercomparison Project, phase 5 (CMIP‐5) to estimate the 11‐year solar cycle responses of ...stratospheric ozone, temperature, and zonal wind during the 1979–2005 period. The analysis is limited to the six CMIP‐5 models which resolve the stratosphere (high‐top models) and which include interactive ozone chemistry. All simulations assumed a conservative 11‐year solar spectral irradiance (SSI) variation based on the Naval Research Laboratory model. These model responses are then compared to corresponding observational estimates derived from two independent satellite ozone profile datasets and from ERA‐Interim reanalysis meteorological data. The models exhibit a range of 11‐year responses with three models (CESM1‐WACCM, MIROC‐ESM‐CHEM and MRI‐ESM1) yielding substantial solar‐induced ozone changes in the upper stratosphere which compare favourably with available observations. The remaining three models do not, apparently because of differences in the details of their radiation and photolysis rate codes. During winter in both hemispheres, the three models with stronger upper‐stratospheric ozone responses produce relatively strong latitudinal gradients of ozone and temperature in the upper stratosphere which are associated with accelerations of the polar night jet under solar maximum conditions. This behaviour is similar to that found in the satellite ozone and ERA‐Interim data, except that the latitudinal gradients tend to occur at somewhat higher latitudes in the models. The sharp ozone gradients are dynamical in origin and assist in radiatively enhancing the temperature gradients, leading to a stronger zonal wind response. These results suggest that simulation of a realistic solar‐induced variation of upper‐stratospheric ozone, temperature and zonal wind in winter is possible for at least some coupled climate models even if a conservative SSI variation is adopted.
There has been remarkable tobacco control progress in many places around the globe. Tobacco industry interference (TII) has been identified as the most significant barrier to further implementation ...of the World Health Organization Framework Convention on Tobacco Control (WHO FCTC). Civil society has been recognised as a key actor in countering TII. While TII has been extensively studied for several decades now, there is little research that focuses on counteractions to limit it and their effectiveness to do so. This scoping review seeks to map the peer-reviewed literature on civil society's activities of countering TII in policymaking to identify common counterstrategies and assess their effectiveness.
Data sources: We searched Embase, IBSS, JSTOR, PubMed, Science Direct, Scopus and Web of Science using the following terms: ("Tobacco industry" OR "Tobacco compan*") AND. ("corporate political activity" OR "CPA" OR "lobbying" OR "interference") AND ("advoca*" OR "counter*" OR "activi*"), without time or language restrictions.
Our selection criteria included peer-reviewed studies that were written in English, German, or Spanish that drew on primary data and/or legal and policy documents and reported at least one specific example of civil society members or organisations countering tobacco industry action-based strategies.
Advocates' counterstrategies were analysed inductively and countered industry strategies were analysed using the Policy Dystopia Model (PDM). Perceptions of effectiveness of countering attempts were analysed descriptively.
We found five common counterstrategies among 30 included papers covering five WHO regions; 1. Exposing industry conduct and false claims; 2. Accessing decision-makers; 3. Generating and using evidence; 4. Filing a complaint or taking legal action; 5. Mobilising coalition and potential supporters. These counterstrategies were used to work against a wide range of industry strategies, which are captured by five action-based strategies described in the PDM (Coalition Management, Information Management, Direct Access and Influence, Litigation, Reputation Management). While some studies reported the outcome of the countering activities, their impact remained largely underexplored.
The review shows that peer-reviewed literature documenting how civil society actors counter TII is scarce. It suggests that advocates employ a range of strategies to counter TII in its different forms and use them flexibly. More work is needed to better understand the effects of their actions. This could stimulate discussions about, and facilitate learning from, past experiences and help to further enhance advocates' capacity.
Major stratospheric sudden warmings are prominent disturbances of the Northern Hemisphere polar winter stratosphere. Understanding the factors controlling major warmings is required, since the ...associated circulation changes can propagate down into the troposphere and affect the surface climate, suggesting enhanced prediction skill when these processes are accurately represented in models. In this study we investigate how different natural and anthropogenic factors, namely, the quasi‐biennial oscillation (QBO), sea surface temperatures (SSTs), anthropogenic greenhouse gases, and ozone‐depleting substances, influence the frequency, variability, and life cycle of major warmings. This is done using sensitivity experiments performed with the National Center for Atmospheric Research's Community Earth System Model (CESM). CESM is able to simulate the life cycle of major warmings realistically. The QBO strengthens the climatological stratospheric polar night jet (PNJ) and significantly reduces the frequency of major warmings through reduction of planetary wave propagation into the PNJ region. Variability in SSTs weakens the PNJ and significantly increases the major warming frequency due to enhanced wave forcing. Even extreme climate change conditions (RCP8.5 scenario) do not influence the total frequency but determine the prewarming phase of major warmings. The amplitude and duration of major warmings seem to be mainly determined by internal stratospheric variability. We also suggest that SST variability, two‐way ocean/atmosphere coupling, and hence the memory of the ocean are needed to reproduce the observed tropospheric negative Northern Annular Mode pattern after major warmings.
Key Points
The QBO reduces the frequency of major SSWs; SST variability increases it
Anthropogenic GHGs and ODSs determine the prewarming phase of major SSWs
Two‐way ocean/atmosphere coupling is needed for the negative AO response after SSWs
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