**Esther Fousert, René Toes and Jyaysi Desai \***

Department of Rheumatology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands<EMAIL_ADDRESS>(E.F<EMAIL_ADDRESS>(R.T.)

**\*** Correspondence<EMAIL_ADDRESS>
Received: 16 March 2020; Accepted: 5 April 2020; Published: 8 April 2020

**Abstract:** Following fifteen years of research, neutrophil extracellular traps (NETs) are widely reported in a large range of inflammatory infectious and non-infectious diseases. Cumulating evidences from in vitro, in vivo and clinical diagnostics suggest that NETs may play a crucial role in inflammation and autoimmunity in a variety of autoimmune diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV). Most likely, NETs contribute to breaking self-tolerance in autoimmune diseases in several ways. During this review, we discuss the current knowledge on how NETs could drive autoimmune responses. NETs can break self-tolerance by being a source of autoantigens for autoantibodies found in autoimmune diseases, such as anti-citrullinated protein antibodies (ACPAs) in RA, anti-dsDNA in SLE and anti-myeloperoxidase and anti-protein 3 in AAV. Moreover, NET components could accelerate the inflammatory response by mediating complement activation, acting as danger-associated molecular patterns (DAMPs) and inflammasome activators, for example. NETs also can activate other immune cells, such as B cells, antigen-presenting cells and T cells. Additionally, impaired clearance of NETs in autoimmune diseases prolongs the presence of active NETs and their components and, in this way, accelerate immune responses. NETs have not only been implicated as drivers of inflammation, but also are linked to resolution of inflammation. Therefore, NETs may be central regulators of inflammation and autoimmunity, serve as biomarkers, as well as promising targets for future therapeutics of inflammatory autoimmune diseases.

**Keywords:** neutrophil extracellular traps (NETs); autoimmunity; autoimmune diseases; inflammation; autoantigens


**5. PSEN 1 and PSEN 2**

Presenilins (PSEN) are an important part of the γ-secretase enzyme activity, and they are responsible for the proteolytic cleavage of APP. γ-secretase is a multimeric complex of PSEN1 or PSEN2, nicastrin, and APH1. All mutations in PSEN1 increase APP cleaving activity by γsecretase, which generates the Aβ42 fragment. The PSEN1 gene is located in chromosome 14 and that of PSEN2 in chromosome 1, both of them are approximately 60% similar [43]. Regarding the gene's structure, it has been demonstrated that the first 4 exons contain untranslated regions, and exons 1 and 2 possess alternative transcription sites. The function of these sites is still unclear. The first ATG is located in exon 4, and its 12 bp is used as an alternative splicing donor site. Exon 9 is subjected to alternative splicing in leukocytes but not in other tissues. Most of the expressed transcripts are polyadenylated after the TAG stop codon in exon 13 [44]. A PSEN 2 variant has been shown to lack exon 5, which has been detected on individuals with sporadic Alzheimer's disease [45].

Several mutations on the PSEN genes are responsible for early familial Alzheimer's disease. The loss of exons 3 and 4 of PSEN demonstrates that transcripts are efficiently translated as truncated proteins at their N-terminal; however, this does not affect their function as amyloid fragment generators [46].

A PSEN2 variant that does not possess exon 5 has been reported to increase the generation of the Aβ40 y 42 fragments [47].


**5. Conclusion**

The current chapter, which was a desktop review, sought to provide an overview of various listener background variables that would influence oral performance ratings. Although the effects of these listener-related variables have been underemphasized in assessing the oral performance of L2 learners, researchers should take their influence into account and endeavor to make the potential contributions of these trait-irrelevant variables as negligible as possible. Listener training is assumed to mediate these extraneous variables. Through training, listeners are equipped with the necessary skills required to rate speech performances of L2 speakers more objectively using predetermined criteria. The effect of listener bias on the evaluation of L2 speech has also been researched in social contexts. As reported in the previous literature, the listeners who harbor negative attitudinal perspectives toward the speakers of a particular social group, especially a stigmatized one, have the proclivity to encode a distorted perception of their speech and more often than not find the speakers unintelligible. Structured intergroup contact, for example, can be a program devised to address the listeners' negative attitudes and reduce their bias. Explicit instruction of L2 listening strategies can also be effective in strengthening L2 listeners' self-efficacy and make them more motivated to embrace the challenges involved in participating in social interactions with NSs and encourage them to regard this as an opportunity to fortify their nascent oral skills. However, research on the listener role in communication is still in its infancy, and future studies should address this issue more comprehensively.

**13**

**Author details**

Mohammadreza Dalman and Okim Kang\* Northern Arizona University, Flagstaff, USA

provided the original work is properly cited.

\*Address all correspondence to<EMAIL_ADDRESS>
© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Listener Background in L2 Speech Evaluation DOI: http://dx.doi.org/10.5772/intechopen.89414* *Listener Background in L2 Speech Evaluation DOI: http://dx.doi.org/10.5772/intechopen.89414*

*Metacognition in Learning*

limitations marked in the prior studies.

address this issue more comprehensively.

**5. Conclusion**

real-life settings. This reluctance on the part of L2 learners would exacerbate the existing bias toward them by NS. To mitigate the bias, if not eliminate it, educators can devise interventions which would foster L2 learners' self-efficacy through strategy instruction and other methods such as providing them with supportive mentors. By fortifying L2 learners' self-efficacy, they would be more encouraged to participate in interactions involving NSs. As a result of more interaction, the intensity of bias held by NSs toward that particular group of NNSs decreases.

With respect to listener background variables, researchers should be cognizant of the fact that some listener-related variables such as listeners' first language status and the amount of their exposure to accented varieties of English are more influential to listeners' perceptions of NNSs' speech than other variables (e.g., listeners' linguistic knowledge and their prior teaching experience). Thus, those variables warrant more attention in selecting listeners for rating NNSs' speech, as they might exert more potent influence and compromise the reliability of the assessment. On the other hand, as pointed out by Kang et al. [3], the effects of the latter variables are more contextually determined and should be considered regarding the type of assessment being administered. For example, if the purpose of speech assessment is evaluating the nuances of pronunciation, listeners' linguistic knowledge and their educational background should be considered for selecting listeners as raters. Additionally, the way that the prior studies have operationalized listener variables needs to be rectified. For example, Kang et al. [3] operationally defined listeners' linguistic sophistication as a function of three factors: (a) the number of foreign languages they spoke, (b) the number of years they studied foreign languages, and (c) the number of linguistic courses they had taken. However, this definition needs to be improved given that with the spread of globalization and emergence of English as an international language (EIL), the concept of foreign language is becoming ambiguous. Thus, future research should take initiatives to address these

The current chapter, which was a desktop review, sought to provide an overview of various listener background variables that would influence oral performance ratings. Although the effects of these listener-related variables have been underemphasized in assessing the oral performance of L2 learners, researchers should take their influence into account and endeavor to make the potential contributions of these trait-irrelevant variables as negligible as possible. Listener training is assumed to mediate these extraneous variables. Through training, listeners are equipped with the necessary skills required to rate speech performances of L2 speakers more objectively using predetermined criteria. The effect of listener bias on the evaluation of L2 speech has also been researched in social contexts. As reported in the previous literature, the listeners who harbor negative attitudinal perspectives toward the speakers of a particular social group, especially a stigmatized one, have the proclivity to encode a distorted perception of their speech and more often than not find the speakers unintelligible. Structured intergroup contact, for example, can be a program devised to address the listeners' negative attitudes and reduce their bias. Explicit instruction of L2 listening strategies can also be effective in strengthening L2 listeners' self-efficacy and make them more motivated to embrace the challenges involved in participating in social interactions with NSs and encourage them to regard this as an opportunity to fortify their nascent oral skills. However, research on the listener role in communication is still in its infancy, and future studies should

**12**


**4. Discussion**

Twitter enables millions of users to share information worldwide in real time. This phenomenon allows policymakers, healthcare stakeholders, and other people to influence and be influenced by opinions and discussions that flow across online social communities, making it possible to share valuable information and practices more quickly and easily than ever before. Such a possibility has become a rich source of value for information-gathering and practical dissemination, in particular for complex and low-intensity diseases like Lupus [46].

Interactivity among online communities makes it possible to renovate not only the healthcare organizations' online approach but the manner in which people's attitudes and intentions regarding health behavior might be influenced [47]. However, valuable information is complex to detect and depict, considering how vast and fast social media platforms work, too often spreading rumors or misinformation [48].

For these reasons, investigating the dynamics played by online communities during specific events like the World Lupus Day can offer a powerful tool to stakeholders for identifying and setting up policy strategies for gathering valuable information and sharing good practices. This ability can offer a concrete tool for decision-makers in dealing with information asymmetry [49], obtain valuable new elements for the decision-making process, promote trust across the identified communities, and promote health-seeking behavior [50].

In our study, we sought to analyze latent themes spread on Twitter during World Lupus Day and detect online user communities' behavior by measuring the users' retweet network.

We measured and found two different types of influencers in our analysis, who behaved and acted differently. There was one type of influencer who was more generally public-oriented, measured on the ratio between the number of followers and the ability to amplify the content they posted, and a second type of influencer, more based on the retweets and network attention count, as an endorsement of their tweet content.

Network influencer users, mostly led by patient organizations, have many followers who tend to have intense connections among themselves, and show more interest in specific topic discussions about the role of social support and policy advocacy. General influencers show less network connection and appear to attract more followers with content related to general disease advice.

Many topics discussed by the two types of influencer were in common. However, the attention posed in some topics were different. This is well represented by the discussion order of topics 2 (Information and advice), 5 (social support), and 6 (advocating), which are swapped in the likelihood order.

Another difference between the topics was posed by the fact that general influencers discussed body symptoms (topic 11), whereas the network influencer discussed topics related to patient involvement (topic 9) and diseases description (topic 8).

To the best of our knowledge, this study is the first to employ a combination of methods to explore deeply latent topic discussions and online communities' interactions regarding a low-prevalence disease like Lupus. Unlike other kinds of diseases such as diabetes, HIV, or stroke, where the vast population offers more opportunities for investigation, low-prevalence or rare diseases can benefit greatly from the application of such methodologies to identify unmet needs or improve the network of care and treatment for patient communities. Therefore, it is critical for public health institutions to systematically explore how to effectively use interactive features on social media to attract public attention and maintain communication with the public.

Further research should also evaluate a qualitative analysis of the selected topics, offering insights that can help improve the judgement in understanding the topic relationships [51].


*Edited by Iraj Rasooli*

There are significant concerns regarding the potential side effects from the chronic use of conventional drugs such as corticosteroids, especially in children. Herbal therapy is less expensive, more readily available, and increasingly becoming common practice all over the world. Such practices have both their benefits and risks. However, herbal self-therapy might have serious health consequences due to incorrect selfdiagnosis, inappropriate choice of herbal remedy or adulterated herbal product. In addition, absence of clinical trials and other traditional safety mechanisms before medicines are introduced to the wider market results in questionable safe dosage ranges which may produce adverse and unexpected outcomes. Therefore, the use of herbal remedies requires sufficient knowledge about the efficacy, safety and proper use of such products. Hence, it is necessary to have baseline data regarding the use of herbal remedies and to educate future health professionals about various aspects of herbal remedies.

ISBN 978-953-307-805-2

Bioactive Compounds in Phytomedicine

Photo by Maor Winetrob / iStock


**3. Polar vortex as a possible reason for the variability of GCR effects on the lower atmosphere**

Antarctic coasts in the South Atlantic and the Indian ocean, as well at climatic Polar fronts over the South Pacific [42]. So, GPH700 anomalies for the Southern hemisphere (**Figure 6b**)

**Figure 6.** *Left*: Temporal variations of GPH700 anomalies in the belts 30–60° and GCR fluxes (detrended yearly values) in the Northern (a) and Southern (b) hemispheres. *Right*: Correlation coefficients for sliding 11-year intervals between LCA and GCR fluxes (dashed lines), GPH700 anomalies and GCR fluxes (solid lines) in the Northern (c) and Southern (d) hemispheres. In the Southern hemisphere, the correlation coefficients are shown for the whole belt 30–60°S (light green line) and for the cyclonic areas (dark green line). Dotted lines show the significance levels of the correlations coefficients

**Figure 5.** Long-term variations of tropospheric pressure (12-month running averages of GPH700) in the belts 30–60° of

were calculated for these cyclonic areas.

88 Cosmic Rays

between GPH700 and GCR fluxes.

the Northern (a) and Southern (b) hemispheres. Red lines show polynomial trends.

It is well known that temporal variability is a characteristic feature of solar-atmospheric links (see, for example, [56]). Correlation links observed between lower atmosphere characteristics and phenomena related to solar activity may weaken, disappear and even change sign depending on time period. So, a violation of the cloud-GCR link in the 2000s is not an extraordinary event. Herman and Goldberg [56] suggested that a reason for temporal variability of solar-atmospheric links may be long-term processes of the Sun which do not influence sunspot numbers and/or some changes of atmospheric conditions. Veretenenko and Ogurtsov [42, 43] showed that temporal behavior of correlation links between surface pressure at extratropical latitudes and sunspot numbers is characterized by a roughly 60-year periodicity caused by changes in the epochs of the large-scale atmospheric circulation. The reversals of the correlation signs were found in the end of the nineteenth century, in the early 1920s, the 1950s and the early 1980s coinciding with climatic regime shifts at middle latitudes [57], as well as with the transitions between cold and warm epochs in the Arctic [58]. So, a violation of the cloud-GCR link in the 2000s seems not to be unexpected and may be associated with the next change of the circulation epochs resulting in the change of GCR contribution to extratropical cyclonic activity and, then, to cloud field formation.

According to the suggestions in [58], the changes of the circulation epochs are closely related to the state of the polar vortex. The polar vortex is a cyclonic circulation forming in a cold air mass in the polar region of the Northern and Southern hemispheres and spreading from the middle troposphere to the upper stratosphere. A circular air motion in the vortex results in a decrease of heat exchange between polar and middle latitudes and this contributes to a temperature drop inside the vortex and an increase of temperature gradients at its edges (see **Figure 7**). The vortex can also be seen as a region of enhanced velocity of zonal winds in the stratosphere during cold months for the given hemisphere, the highest values being observed at latitudes 50–80° at the pressure levels above 50 hPa.

The polar vortex is an important factor of the large-scale atmospheric circulation and climate variability. Gudkovich et al. [58] showed that the rotation of cold and warm epochs in the Arctic are caused by changes of the vortex intensity, warm and cold epochs being associated with a strong and weak vortex, respectively. Indeed, under strong vortex conditions cyclone tracks are shifted to the north [59] and more North-Atlantic cyclones arrive in the polar region bringing warm air. An important feature of the polar vortex is its influence on the troposphere-stratosphere coupling via planetary waves. Propagation of planetary waves upward depends on stratospheric circulation (for example, [60, 61]). If the vortex is strong and a velocity of western winds in the stratosphere exceeds some critical value, these waves are reflected back to the troposphere. If the vortex is weak, planetary waves propagate freely upward. So, the stratosphere may influence the troposphere under a strong vortex regime. Under a weak vortex, only the troposphere may influence the stratosphere. This point seems to be of importance to understand the observed temporal variability of solar activity/GCR effects on tropospheric circulation.

Let us consider variations of the polar vortex intensity and compare them with temporal behavior of GCR effects on cyclonic activity and clouds. To characterize the vortex strength, we used zonally averaged velocity of western winds (i.e. the U-component of wind velocity directed from west to east from [55]) at the level 50 hPa (~20 km). In **Figure 8** (top panel) there are presented variations (detrended values) of mean zonal wind velocity in the belts 60–80° in both hemispheres averaged for six cold months (October-March in the Northern hemisphere and April-September in the Southern one). The correlation coefficients R(GPH, FCR) and R(LCA,FCR) for sliding 11-year intervals are shown in **Figure 8** (bottom panel).

From the middle 1980s to the middle 1990s the polar vortices in both hemispheres were enhanced. The vortex enhancement was the most prominent in the Northern hemisphere, the wind velocity increasing up to 4–7 m.s−1 relative to the trend values. This agrees well with the data [62] showing no strong sudden stratospheric warming destroying the vortex in the indicated period. The vortex in the Southern hemisphere is more stable than that in the Northern one; however, we can also see a noticeable increase in wind velocity. The data in **Figure 8** show that in the period of the vortex enhancement most statistically significant correlations between pressure (cyclonic intensity) and GCR fluxes, as well as between low clouds and GCR fluxes take place. In the late 1990s both the vortices and the correlations GPH–GCR and LCA–GCR in both hemispheres started weakening. A sharp decrease of the wind velocities resulting in the vortex transition to its weak state occurred near 2000 in both hemispheres. The reversal of correlation coefficients under study coincided well with the transition of the vortices to a weak state. Thus, the presented data allow suggesting that the violation of the correlation between low cloudiness and GCR intensity detected on the decadal scale is closely

**Figure 8.** *Top*: Variations of mean zonal velocity of western winds (the U-component) at the stratospheric level 50 hPa in the belt 60–80° for cold months in the Northern (a) and Southern (c) hemispheres. Thick lines show 11-year running averages and polynomial fits. *Bottom*: Correlation coefficients for sliding 11-year intervals between LCA and GCR fluxes (dashed lines), GPH700 anomalies and GCR fluxes (solid lines) in the Northern (b) and Southern (d) hemispheres. Dotted lines show the significance levels of the correlation coefficients. The period of an enhanced vortex is marked by vertical dashed lines.

Galactic Cosmic Rays and Low Clouds: Possible Reasons for Correlation Reversal

http://dx.doi.org/10.5772/intechopen.75428

91

The results of this study confirm that the changes of the atmosphere state, in particular, of the intensity of the stratospheric polar vortex, may be a real reason for the observed temporal variability of solar-atmospheric links. Indeed, sign reversals of correlation links between

related to the change of the polar vortex strength.

**Figure 7.** Distribution of mean monthly temperature at the pressure level 20 hPa (a) and of magnitude of horizontal temperature gradients (b) in the Northern hemisphere in January 2005. White asterisk indicates a minimum of temperature in the vortex; thick black line connects the points of maximal values of the temperature gradient at given latitude.

Galactic Cosmic Rays and Low Clouds: Possible Reasons for Correlation Reversal http://dx.doi.org/10.5772/intechopen.75428 91

in a decrease of heat exchange between polar and middle latitudes and this contributes to a temperature drop inside the vortex and an increase of temperature gradients at its edges (see **Figure 7**). The vortex can also be seen as a region of enhanced velocity of zonal winds in the stratosphere during cold months for the given hemisphere, the highest values being

The polar vortex is an important factor of the large-scale atmospheric circulation and climate variability. Gudkovich et al. [58] showed that the rotation of cold and warm epochs in the Arctic are caused by changes of the vortex intensity, warm and cold epochs being associated with a strong and weak vortex, respectively. Indeed, under strong vortex conditions cyclone tracks are shifted to the north [59] and more North-Atlantic cyclones arrive in the polar region bringing warm air. An important feature of the polar vortex is its influence on the troposphere-stratosphere coupling via planetary waves. Propagation of planetary waves upward depends on stratospheric circulation (for example, [60, 61]). If the vortex is strong and a velocity of western winds in the stratosphere exceeds some critical value, these waves are reflected back to the troposphere. If the vortex is weak, planetary waves propagate freely upward. So, the stratosphere may influence the troposphere under a strong vortex regime. Under a weak vortex, only the troposphere may influence the stratosphere. This point seems to be of importance to understand the observed temporal variability of solar activity/GCR

Let us consider variations of the polar vortex intensity and compare them with temporal behavior of GCR effects on cyclonic activity and clouds. To characterize the vortex strength, we used zonally averaged velocity of western winds (i.e. the U-component of wind velocity directed from west to east from [55]) at the level 50 hPa (~20 km). In **Figure 8** (top panel) there are presented variations (detrended values) of mean zonal wind velocity in the belts 60–80° in both hemispheres averaged for six cold months (October-March in the Northern hemisphere and April-September in the Southern one). The correlation coefficients R(GPH, FCR)

**Figure 7.** Distribution of mean monthly temperature at the pressure level 20 hPa (a) and of magnitude of horizontal temperature gradients (b) in the Northern hemisphere in January 2005. White asterisk indicates a minimum of temperature in the vortex; thick black line connects the points of maximal values of the temperature gradient at given

and R(LCA,FCR) for sliding 11-year intervals are shown in **Figure 8** (bottom panel).

observed at latitudes 50–80° at the pressure levels above 50 hPa.

effects on tropospheric circulation.

90 Cosmic Rays

latitude.

**Figure 8.** *Top*: Variations of mean zonal velocity of western winds (the U-component) at the stratospheric level 50 hPa in the belt 60–80° for cold months in the Northern (a) and Southern (c) hemispheres. Thick lines show 11-year running averages and polynomial fits. *Bottom*: Correlation coefficients for sliding 11-year intervals between LCA and GCR fluxes (dashed lines), GPH700 anomalies and GCR fluxes (solid lines) in the Northern (b) and Southern (d) hemispheres. Dotted lines show the significance levels of the correlation coefficients. The period of an enhanced vortex is marked by vertical dashed lines.

From the middle 1980s to the middle 1990s the polar vortices in both hemispheres were enhanced. The vortex enhancement was the most prominent in the Northern hemisphere, the wind velocity increasing up to 4–7 m.s−1 relative to the trend values. This agrees well with the data [62] showing no strong sudden stratospheric warming destroying the vortex in the indicated period. The vortex in the Southern hemisphere is more stable than that in the Northern one; however, we can also see a noticeable increase in wind velocity. The data in **Figure 8** show that in the period of the vortex enhancement most statistically significant correlations between pressure (cyclonic intensity) and GCR fluxes, as well as between low clouds and GCR fluxes take place. In the late 1990s both the vortices and the correlations GPH–GCR and LCA–GCR in both hemispheres started weakening. A sharp decrease of the wind velocities resulting in the vortex transition to its weak state occurred near 2000 in both hemispheres. The reversal of correlation coefficients under study coincided well with the transition of the vortices to a weak state. Thus, the presented data allow suggesting that the violation of the correlation between low cloudiness and GCR intensity detected on the decadal scale is closely related to the change of the polar vortex strength.

The results of this study confirm that the changes of the atmosphere state, in particular, of the intensity of the stratospheric polar vortex, may be a real reason for the observed temporal variability of solar-atmospheric links. Indeed, sign reversals of correlation links between troposphere pressure in the Northern hemisphere and sunspot numbers during the twentieth century coincided with the changes in the evolution of the large-scale circulation, which, in turn, were associated with the polar vortex transitions from one state to another [42, 43]. A roughly 60-year periodicity was revealed in the vortex strength, the phases of the Arctic Oscillation being used as a proxy of the vortex intensity [43], which is consistent with a similar periodicity found earlier in correlation links between pressure at extratropical latitudes and sunspot numbers [42]. Thus, the data presented in this study revealed the next change of the vortex state, which resulted in the reversal of correlation links between atmosphere characteristics and phenomena associated with solar activity.

**4. Conclusion**

**Author details**

**References**

LA>2.0.CO;2

Svetlana Veretenenko1

\*, Maxim Ogurtsov1

\*Address all correspondence to<EMAIL_ADDRESS>
1991;**96**:18537-18549. DOI: 10.1029/91JD01992

1 Ioffe Institute, Sankt-Petersburg, Russia

2 Natural Resources Institute, Finland

The question of cloud-GCR links remains controversial and requires new studies, both experimental and theoretical, to evaluate a real contribution of galactic cosmic rays to solar activity influence on the Earth's climate. The data presented in this chapter show that possible links between clouds and GCR variations on the decadal and longer time scales could involve not only direct (microphysical) effects, but mostly indirect ones mediated by circulation changes. This should be taken into account when considering long-term GCR effects on the cloudiness state. An important part in the formation of long-term GCR effects on cloud cover at extratropical latitudes seems to be played by the stratospheric polar vortex. The state of the vortex controls the stratosphere-troposphere coupling creating more favorable conditions for GCR influence on extratropical cyclonic activity and, consequently, on cloud cover under a strong vortex regime. In this connection, a high positive correlation of low cloudiness and GCR variations in the 1980s–1990s, which was the period of a strong vortex, may be explained by a pronounced intensification of extratropical cyclones associated with GCR increases in the minima of the 11-year solar cycle. A sharp change of the vortex state near 2000 both in the Northern and Southern hemispheres altered the character of GCR effects on cyclone evolution and, thus, resulted in a violation of cloud-GCR correlation links observed earlier under strong vortex conditions.

Galactic Cosmic Rays and Low Clouds: Possible Reasons for Correlation Reversal

http://dx.doi.org/10.5772/intechopen.75428

93

, Markus Lindholm2

[1] Harrison EF, Minnis P, Barkstrom BR, Ramanathan V, Cess RD, Gibson GG. Seasonal variation of cloud radiative forcing derived from the earth radiation budget experiment. Journal of Geophysical Research. 1990;**95**:18687-18703. DOI: 10.1029/JD095iD11p18687

[2] Ardanuy PE, Stowe LL, Gruber A, Weiss M. Shortwave, longwave, and net cloud-radiative forcing as determined from Nimbus 7 observations. Journal of Geophysical Research.

[3] Dickinson RE. Solar variability and the lower atmosphere. Bulletin of the American Meteorological Society. 1975;**56**:1240-1248. DOI: 10.1175/1520-0477(1975)056<1240:SVAT

and Risto Jalkanen2

The detected modulation of long-term solar activity/GCR effects on troposphere dynamics by the polar vortex state seems to be due to its role in troposphere-stratosphere coupling via planetary waves. As it was said above, the stratosphere may influence the troposphere only under a strong vortex regime when planetary waves are reflected back to the troposphere. Hence, a strong vortex regime seems to be more favorable to transfer a signal produced in the polar stratosphere by GCRs (or other solar activity phenomena) to the troposphere, as changes in the vortex formation region may influence its intensity and, then, conditions for propagation of planetary waves. Indeed, we can see that GCR effects on cyclonic activity are most pronounced under a strong vortex (see **Figures 6** and **8**) that agrees well with the previous data [42]. Thus, the results of this study provide new evidence for an important part of the polar vortex in the mechanism of solar activity/GCR influence on the troposphere dynamics on the decadal and longer time scales.

Let us note a favorable location of the vortex for GCR effects on the lower atmosphere. The vortex is formed in the region of low geomagnetic cutoff rigidities (Rc < 2–3 GV) that allows particles with a broad energy range to precipitate, including low-energy GCR component which is strongly modulated by solar activity. Wind velocities in the vortex reach maximal values at the heights ~20–30 km where the maximum of the transition curve is observed [63]. This height range also involves the layer of stratospheric aerosols consisting mainly of water solution of sulfuric acid (the Junge layer) (for example, [64]). This creates conditions for influence of ionization changes on aerosol formation which, in turn, may influence the radiative-thermal balance and temperature in the stratosphere and, as a result, the vortex characteristics.

We should also stress that the data presented above do not imply a lack of GCR influence on microphysical processes in clouds. However, they suggest that the formation of cloud-GCR correlation links differs depending on the time scale. GCR variations may influence nucleation rates and growth of particles in clouds according to IMN and/or electric mechanisms [3–11], but this influence may be detected only on rather short time scales (from hours to several days) until the response of atmosphere dynamics to radiative forcing of cloud changes enhances or weakens initial microphysical effects. On longer time scale direct effects of GCRs on cloud formation are masked by more powerful indirect effects through circulation changes associated with GCR variations, these indirect effects depending on the polar vortex state. Taking into account this suggestion, the violation of cloud-GCR correlation links detected near 2000 may be explained.