Annular Solar Eclipse on 26 December 2019 and its Effect on Trace Pollutant Concentrations and Meteorological Parameters in Kannur, India: a Coastal City

1. INTRODUCTION

Solar eclipse is a natural phenomenon that provides a distinct reduction of solar radiation for a fixed duration due to the obscuration of the solar disc by the moon. Being a rare astronomical event, it provides a unique occasion to investigate the spontaneous changes in photochemistry, dynamics, and boundary layer height (BLH) in the atmosphere due to the variations in the ascending and descending phases of solar radiation (Stoev et al., 2005; Szalowski, 2002; Koepke et al., 2001; Winkler et al., 2001; Fernandez et al., 1996; Manohar et al., 1995). Several investigators have reported the effects of various atmospheric parameters at the time of a solar eclipse in different parts of the globe (Gröbner et al., 2017; Dutta et al., 2011; Krezhova et al., 2008; Aplin and Harrison, 2003; Dolas et al., 2002; Foken et al., 2001; Vogel et al., 2001; Hanna, 2000; Prenosil, 2000; Anderson, 1999; Eaton et al., 1997; Segal et al., 1996). Various researchers have explored the pronounced variations in the atmospheric boundary layer (ABL) height at the eclipse event (Ratnam et al., 2010; Founda et al., 2007; Krishnan et al., 2004; Kapoor et al., 1982; Raman, 1982). Subrahamanyam et al. (2012) observed a double mixed boundary layer between 700 and 1500 m during the solar eclipse on 15 January 2010 at Thiruvananthapuram, which was due to the horizontal advection of air mass. The atmospheric turbulence decay during the total solar eclipse of 11 August 1999 was examined by Anfossi et al. (2004), and their observations were in good agreement with the theoretical model of turbulence decay.

Studies were focused on the eclipse induced surface air temperature variations and reported a sharp decrease in air temperature at the maximum phase of the eclipse (Calamas et al., 2019; Nymphas et al., 2009; Kolarz et al., 2005; Krishnan et al., 2004; Sethuraman, 1982). Wang and Liu (2010) observed a warming of 7°C at 17 km altitude due to thermal contraction, and cooling of 2°C in the troposphere due to reduction in solar heating during the total solar eclipse on 22 July 2009. Likewise, a temperature reduction of 2°C was observed around the tropopause over Thumba by Subrahamanyam et al. (2011) at the annular solar eclipse of 2010, and revealed that these changes were associated with a significant reduction in turbulent kinetic energy, momentum flux, and sensible heat flux at the peak period of the eclipse. Observations of land surface temperature changes over Europe during the total solar eclipse on March 2015 by Elizabeth (2016) found to drop up to several degree Celsius, and this temperature drop was correlated with solar intensity variation. Muraleedharan et al. (2011) reported an abnormal warming in the upper troposphere due to decrease in tropopause height on the solar eclipse day 2010 at Goa, India.

Generally, humidity increases with the reduction in surface air temperature (Bhat and Jagannathan, 2012), and this cooling alters the stability of boundary layer in the lower atmosphere (Gorchakov et al., 2008; Praveena et al., 2004). Jokinen et al. (2017) identified the formation of new particles caused by aerosol loading and lack of oxidized organic compounds during the solar eclipse in 2015. Apart from the variations observed in meteorological parameters and atmospheric dynamics, solar eclipses induced substantial impact on the stratospheric and surface O₃ photochemistry, and several studies have been carried out in this direction (Gerasopoulos et al., 2008; Zanis et al., 2007; Tzanis, 2005; Fabian et al., 2001). Observations of total column O₃ using ground based devices during eclipse events by different groups show a decrease in O₃ concentration during the maximum phase of eclipse (Chudzynski et al., 2001; Zerefos et al., 2000; Mims and Mims, 1993).

As the sunlight is obscured for few minutes, the weather parameters fluctuate, resulting in a drastic change in the concentrations of atmospheric O₃ and nitrogen dioxide (Amiridis et al., 2007; Fabian et al., 2001). Manchanda et al. (2012) have reported a decrease in the O₃ concentration in the stratosphere and troposphere instantly after the maximum phase of the eclipse due to temperature cooling, on the solar eclipse of 15 January 2010 at Thiruvananthapuram. Only very few studies have been reported on the changes in the surface O₃ and their photochemistry during the eclipse event in India (Girach et al., 2012; Reddy et al., 2012; Vyas et al., 2012; Nishanth et al., 2010; Sharma et al., 2010; Naja and Lal, 1997; Srivastava et al., 1982). In addition, they also validated the model simulation response, which was in agreement with the observed effect.

This is the second study on the variation of air pollutants on solar eclipse, after the partial solar eclipse observed on 15 January 2010 at Kannur; in which we could investigate the variations of surface O₃, NO_x and meteorological parameters at Kannur University campus. Here we describe the results on the variation of surface O₃, NO, NO₂, CO, SO₂, NH₃, particulate matters (PM₁₀ and PM_2.5), Volatile Organic Compounds include Benzene, Tolune, Ethyle Benzene, Xylenes (collectively called BTEX), total ozone column (TOC) and meteorological parameters (total solar radiation, temperature, relative humidity, wind speed and wind direction) at Kannur Town. Further, a detailed account of the inter-correlation between observed trace pollutants and meteorological parameters is discussed. In addition to these, theoretical calculation and model simulation for the photodissociation coefficient j(NO₂) is discussed in this paper. This investigation shows that at Kannur town, which is highly polluted than Kannur University Campus, the synoptic movement of atmospheric trace species plays a crucial role in the progress of eclipse induced changes in the surface O₃ and other trace pollutant.

2. METHODS

2. 1 Description of the Eclipse

The annular solar eclipse is a phenomenon in which the sun is partially or completely obscured when the moon comes between the sun and earth, causing the sun’s outer surface appears as a ring. The annular solar eclipse of December 26, 2019 started from Hofuf in Saudi Arabia, Qatar, and UAE. It was then crossed over India, Sri Lanka, Malaysia, Indonesia, Singapore, and ended at Guam in the China Sea. Fig. 1(a) shows the path of solar eclipse over Indian region. At Kannur, the annular solar eclipse began at 08:04 IST, reached total obscuration at 09:26 IST and completed at 11:05 IST. The total eclipse lasted for 3 minutes and 12 seconds with a magnitude of 0.98, when the Moon came close to the centre of the Sun. The duration of the eclipse was 3 Hrs 1 minute at Kannur.

Fig. 1.

(a) Eclipse path passing over Indian region (source: NASA tracks the path of the annular eclipse on Google Maps), (b) aerial view of observation centre and surroundings at Kannur town, (c) timings for the annular solar eclipse viewed from Kannur (The image taken by using Canon EOS 6D Mark II Camera).

3. RESULTS AND DISCUSSION

3. 1 Variation of Solar Radiation, Surface and Total Column O₃

In order to study the influence of solar eclipse on the variation of air pollutants over Kannur, the study period was divided into two spans; viz., eclipse day (26 December 2019) and control days (pre-eclipse days of December 23, 24, 25 and post-eclipse days of December 27, 28, 29). Fig. 2 shows the day time variations in (a) solar radiation, and (b) surface O₃ at the observational site on the solar eclipse day and the control days. The error bars in the figure shows a standard deviation in the respective parameter for 6 control days. The beginning, maximum and the end of the solar eclipse are marked as B, M and E in the figure with vertical lines. The figure displays a steady decrease in solar insolation observed from 08:04 IST and became minimum during the maximum obscuration at 09:26 IST, and then started increasing.

Fig. 2.

Variations of (a) solar radiation and (b) surface O3 observed during eclipse day and control days.

The intensity of solar radiation regained its normal value by the end of the eclipse (11:05 IST). It was found that the intensity of solar radiation declined from 376±101 Wm^-2 (average value on control days) to 26 Wm^-2 on the eclipse day at 9.26 IST with a reduction of 93%. Likewise, surface O₃ concentration started to decrease from 9.3 pbbv at the beginning of the eclipse (08:15 IST) and reached its minimum value of 6.5 ppbv at 09:26 IST, and after full obscuration it started to increase till the end of the eclipse. During control days and eclipse day, surface O₃ concentration reaches its peak value at the noon time, 30 minutes after the maximum intensity of solar radiation, while the O₃ decline was in phase with solar radiation on eclipse day. Thus, a sharp decrease in O₃ concentration (61.5%) was noticed during the maximum phase of the eclipse at 09:26 IST when compared to the respective values in the control days. This decline of O₃ was due to the slow rate of photolysis of NO₂ in the declining phase of the solar intensity as shown in the figure. This is in tune with the similar observations at the maximum phase of solar obscuration during the eclipse on 15 January 2010, at Kannur University campus (Nishanth et al., 2011), and at Thiruvananthapuram (Girach et al., 2012).

Studies carried out at various locations during different solar eclipses have shown different magnitudes of change in the concentration of surface O₃. Naja and Lal (1997) have observed a decrease of 18-21% at Ahmedabad during the solar eclipse of 24 October 1995 and Abram et al. (2000) have reported a decrease of 8% of O₃ at Silwood Park, Ascot during the solar eclipse of 11 August 1999. Tzanis et al. (2008) have observed a higher rate of change O₃ one hour after the maximum phase of the solar obscuration over four observation centres in Greece during the solar eclipse of 29 March 2006.

The day time variations of total column O₃ on the eclipse day and the control days are shown in Fig. 3. Column O₃ concentration was found to increase during day time when photochemical reactions occurs in the presence of solar radiation, N₂O₅, and nitrogen oxides such as NO, NO₂ and NO₃ (Kostadinov et al., 1999). Actinic flux in troposphere may have a strong reduction by stratospheric O₃ absorption by which photochemistry in the troposphere depends on stratospheric O₃ concentrations (Madronich and Flocke, 1999). In high NO_x environments, higher photo-dissociation rate coefficients (j) result in tropospheric O₃ production; while in low NO_x regions, O₃ destruction is enhanced (Fuglestvedt et al., 1995; Madronich and Granier, 1992; Liu and Tranier, 1988).

Fig. 3.

Variation of total column O3 for control days and the eclipse day.

Fig. 4.

Variations of (a) CO, (b) NO, (c) NO2, (d) SO2, (e) NH3 and (f) BTEX observed during eclipse day and control days.

The average concentration of total column O₃ varied between 248±4.4 to 285±8.2 DU during control days, and it showed a lower concentration on eclipse day. From the figure, it is clear that the total column O₃ concentration was found to be decreasing from the beginning of the eclipse (08:04 IST) and reached the minimum during the maximum phase of the eclipse and then returns to normal value after the eclipse event. With respect to control days, TCO was decreased from 262±6.6% to 231±5.3% in a time of 10 minutes after the maximum phase of solar obscuration. Thus, a change of 31 DU which correspond to 11.8% change in TCO was observed. A similar variations were reported at Thiruvananthapuram (Kumar et al., 2014) and New Delhi (Chakrabarty et al., 2001) during the eclipse events in 2010 and 1995. Chakrabarty et al. (1997) observed a sharp decrease in total column ozone before 10 minutes of maximum obscuration of the Sun over Ahmedabad during the solar eclipse of 1997. Using MICROTOPS Sun photometer, Kazadzis et al. (2007) reported that a decrease in 30-40 DU total column ozone in Kastelorizo, Greece on the day of eclipse on 29 March 2006. The measurements of total column ozone using MICROTOPS II Ozone Monitor by Girach et al. (2012) show a decrease of 14 DU at the maximum phase of eclipse at Thiruvananthapuram during 2010. Further they observed a fluctuation of columnar ozone about 20 minutes after the maximum phase of eclipse due to the presence of wave activity. Thus, the observed variation in TCO over Kannur, during the eclipse needs a detailed investigation incorporating fluid dynamics, and photochemical models to explore the boundary layer dynamics and associated vertical mixing.

3. 3 Variations of Particulate Matters

Particulate Matters (PM₁₀ and PM_2.5) are considered to be one of the significant components in the atmosphere, present in the form of solid and liquid suspensions. The primary source of PM in a non-industrialised location is the exhaust of automobiles (Liu et al., 2015; Srimuruganandam and Nagendra, 2011; Cheng et al., 2006; Latha and Badarinath, 2005). Concentration of particulate matters are depending on the variation of boundary layer height, wind speed and direction, surface solar radiation, cloud cover, sea level pressure, and precipitation. Larger boundary layer and stronger surface wind gust help speedy dispersion of particulate matters (Kim and Kim, 2020; Yang et al., 2016). From night to early morning hours, atmosphere is almost stable without significant mixing which provide a favorable condition for the accumulation of particulate matters. With an increase in solar radiation in the afternoon, different environmental features mentioned above tend to accelerate the dispersion of particulate matters (Miao and Liu, 2019; Kim et al., 2017). Day time variations of PM₁₀ and PM_2.5 observed during eclipse day, and control days over Kannur are shown in Fig. 5. Diurnal variations of PM₁₀ and PM_2.5 shows higher concentrations during morning (09:00 to 12:00 IST) and evening (16:00 to 20:00) hours due to the peak traffic and late-night hours due the accumulation of pollutants by shallow boundary layer. During eclipse day, the concentrations of PM₁₀ and PM_2.5 started increase from the beginning of the eclipse, and reaches higher concentrations during the maximum phase of eclipse. The magnitude of PM₁₀ increased from 94.88±18.44 to 112.4 μg/m³ and PM_2.5 from 62.52±14.04 to 69.56 μg/m³ with percentages of increase 18.5% and 11.3%, respectively. This enhancement in PM₁₀ and PM_2.5 may be influenced by the shallow boundary layer and relatively low wind speed during the eclipse.

Fig. 5.

Variations of (a) PM10, (b) PM2.5 observed during eclipse day and control days.

3. 4 Variations of Meteorological Parameters

In order to understand the impact of eclipse on terrestrial meteorological parameters, the daily variations of surface air temperature, relative humidity, wind speed and wind direction were analysed in detail. The required meteorological parameters were measured by using an automatic weather station (LSI LASTEM) established in the observation centre during the eclipse day and 6 control days. The diurnal variations in temperature, relative humidity, wind speed and wind direction observed on the control and eclipse days are shown in the Fig. 6. The eclipse proscribes sun light incident on the Earth’s surface, and that could significantly affect the surface air temperature, and relative humidity distribution. Consequently, observed air temperature was decreased from 29.13±1.35°C (with respect to control day’s average) to 25.04°C with a temperature drop of 4.09°C during maximum phase of the eclipse. This temperature dip was 16.3% with a time lag of 17 minute at the full phase of the eclipse. The diurnal variation of temperature is shown in the Fig. 6(a). The reduction in temperature during eclipse episode induced a corresponding increase in relative humidity as shown in the Fig. 6(b). The relative humidity was found to be increased from 60.41±4.2% (with respect to control day’s average) to 76.82% during the maximum phase of solar obscuration. It resulted a change of 27.1% of increase in RH with a time lag of 18 minutes at the maximum phase of the eclipse. Namboodiri et al. (2011) have reported a temperature dip of 3.5°C, and 19% increase in relative humidity at a peninsular Indian coastal station (Thumba) during an eclipse on 15 January 2010.

Fig. 6.

Variations of (a) temperature, (b) relative humidity, (c) wind speed, (d) wind direction observed during eclipse day and control days.

The wind speed was found to be decreased to 36.1% with respect to control days at the maximum phase of eclipse (Fig. 6(c)), while wind direction remained unchanged during eclipse episode (Fig. 6(d)). The observed wind speed was found to decrease during the starting of eclipse, and reached its low at the full obscuration, and tended to increase and regain its normal value after completing the eclipse episode. This decrease in wind speed might be due to the freezing of atmospheric boundary due to the absence of solar radiation (Sharma et al., 2010). Certainly, these deviations in weather parameters will persuade the distresses in the photochemistry of trace gases in the lower atmosphere.

The concentrations of O₃ precursor gases significantly varied during the solar eclipse episode, and the percentage of variations are listed in the Table 1. The observed NO concentrations did not show any substantial variation compared to the control days which reveal the absence of titration of O₃ leading to its destruction. From the table, it is evident that, 93% of reduction in solar radiation resulted in a decrease in temperature by 16.3% and O₃ concentration by 61.5% at the maximum phase of eclipse. At the same time NO₂, CO, and RH showed an enhancement by 42.2%, 28.9% and 27.1%, respectively.

Table 1.

Percentage of changes observed in solar radiation, O3, NO2, CO, SO2, NH3, BTEX, temperature and relative humidity during the solar eclipse episode with respect to control days.

3. 5 Correlation between Air Pollutants and Meteorological Parameters

Statistical analysis (Pearson’s test) is performed, and the resulted correlation coefficient between observed trace gases, particulate matters and meteorological parameters over the study area during eclipse episode is shown in the Table 2. The results point out that O₃ shows a positive correlation between NO, NH₃, solar radiation, temperature, wind speed and negative correlation with NO₂, CO, SO₂, PM₁₀, VOC’s (BTEX) and relative humidity. A good positive correlation between O₃ and solar radiation (r=0.90) indicates the production of O₃ by the photolysis of NO₂. Further, the correlation between O₃ and wind speed (r=0.68) revealed the transport of O₃ over the observational site. Meteorological parameters such as solar radiation and temperature are in positive correlation with NO, and negative correlation with NO₂, CO, SO₂, NH₃, PM₁₀ and VOC’s. The negative correlations existing between wind speed with SO₂, NO₂, CO and PM₁₀ point out the reduction of these pollutants by the wind. Relative humidity shows positive correlations with NO, SO₂ and negative correlations with O₃, NO₂, CO, NH₃, PM₁₀, VOC’s and solar radiation. PM₁₀ shows a negative correlation (r=-0.76) with temperature, which is due to the thermally induced decreased convection of particulate matters and condensation of VOC̓s. Similarly PM₁₀ shows a negative correlation with (r=-0.67) with relative humidity.

Table 2.

Correlation coefficients between observed trace gases, particulate matter and meteorological parameters during eclipse episode.

3. 6 Theoretical Calculation and Model Simulation for j(NO₂)

Photodissociation rate coefficients (j values) is one of the vital parameters that unfolds the chemistry of air pollution. They depend on absorption cross sections, quantum yield and also the availability of solar radiation at any specific location in the atmosphere. The photolysis rate coefficient j(NO₂) at a location is estimated by the equation j(NO₂)=∫F(λ)σ(λ,T)φ(λ,T)dλ, and the temporal variation of j(NO₂) is shown in Fig. 7(a). It is found that the j(NO₂) started to increase in the morning of the eclipse day, just as in the normal day. Its value gradually reduced in tune with the intensity of solar radiation in its descending and ascending phases of the eclipse and reached its minimum level during the complete obscuration. Thus, a change in the j(NO₂) was found in tune with the observed variation of surface O₃. The photolysis rate coefficient j(NO₂) was found to be reduced by about 87.5% during the maximum phase of the eclipse with respect to the control days. This result reveals that the photochemical production of surface O₃ from NO₂ in the presence of sunlight. Therefore, it is further realised that surface O₃ and j(NO₂) found a positive relation during day time hours.

Fig. 7.

Diurnal variation of (a) theoretically calculated j(NO2), (b) Model simulated j(NO2) for control day and eclipse day.

The Tropospheric Ultraviolet-Visible (TUV) model was used in the wavelength range 121-750 nm, for calculating the spectral irradiance, spectral actinic flux, and photodissociation coefficients (j-values). The TUV model simulations of j(NO₂) were carried out to study the influence of solar radiation on the photochemical production of O₃ from NO₂ over the observational period. More details about the model is described by Madronich and Flocke, (1999). The model simulations were carried out by keeping all the input parameters kept constant in their normal concentrations, and by varying the intensity of solar radiation from lower to maximum. The model simulated of j(NO₂) variations are shown in Fig. 7(b) for the control days and eclipse day. From the figure, it is evident, that similar to theoretical calculation, j(NO₂) started to decline from its normal value of 1.19×10⁸ molecules cm^-3 sec^-1 (beginning of eclipse at 08:06 IST) to 0.245×10⁸ molecules cm^-3 sec^-1 (maximum phase of the eclipse at 09:26 IST). The decline in the (jNO₂) during the maximum phase of eclipse is calculated to be 91.65% with respect to control days at the same time. After completing maximum obscuration, the j(NO₂) again started to increase and reaches its normal value later completing the eclipse episode at 11:05 IST.

4. CONCLUSION

A total solar eclipse provides a rare opportunity to study the effects of atmospheric changes due to the gradual dimming of solar radiation in the daytime. At Kannur, the annular solar eclipse began at 08:04 IST, reached maximum obscuration at 09:26 IST and completed at 11:05 IST. The highlights of the observation are the following:

• ▶ At the maximum phase of eclipse, solar radiation displayed a sharp decline (93%), which resulted a strident reduction (61.5%) in surface O₃ concentration due to reduced photochemical activity. The observation of total column O₃ using MICROTOPS II recorded a decrease of 31 DU in a time lag of 10 minutes from the maximum phase of the eclipse.
• ▶ Increasing trends in ground level CO and NO₂ were observed from the beginning of eclipse, and they reached their maximum concentrations during the peak of the eclipse. This enhancement in CO and NO₂ concentration were estimated to be 28.9% and 42.2%, respectively, and this increase might be due to the reduced photochemical reactions, lower boundary layer height, low wind speed and morning traffic. NO concentration remains unchanged during the maximum phase of eclipse.
• ▶ Since O₃ acts as a major oxidising agent for sulphur, consequently a decreased concentration of SO₂ was observed on the day of eclipse. With respect to control day’s concentration, SO₂ decreased to 17.6% and NH₃ increased to 11.3% during the maximum phase of solar obscuration. Volatile organic compounds collectively measured BTEX was found to increase 22.6% during the maximum solar obscuration.
• ▶ Meteorological parameters such as surface air temperature, relative humidity, wind speed and wind direction were analysed on the day of eclipse. During the maximum phase of the eclipse, surface air temperature and wind speed were dropped to 16.3% and 36.1%, respectively, and relative humidity increased to 27.1%. The concentrations of PM₁₀ and PM_2.5 started increasing, and attained a peak during the maximum phase of the eclipse. This upsurge leads to 18.5% and 11.3% for PM₁₀ and PM_2.5 concentrations, respectively during eclipse episode.
• ▶ The variation of photodissociation coefficient j(NO₂) values were theoretically calculated from the observed data, and a reduction of 87.5% was found. This shows a good agreement with the model simulated j(NO₂) reduction of 91.65%.

The results of this study are preliminary at a polluted costal city in north Kerala during a solar eclipse. This study revealed a synoptic movement of atmospheric trace species over Kannur town, a polluted location compared to Kannur University campus in which the earlier observations were made in 2010. The observed abrupt changes in surface O₃ and other trace pollutants should be validated with more observations with the support of other prominent trace species including OH radical and organic samples to understand their role in O₃ chemistry and transport in the coming eclipse events.

Acknowledgments

The authors are grateful to the Indian Space Research Organization (ISRO), Bangalore for the financial support provided through Atmospheric Chemistry, Transport, and Modeling project of Geosphere Biosphere Programme. Likewise, authors express their gratitude to Kerala State Council for Science Technology and Environment (KSCSTE) for granting financial support for the study of air pollutants over Kannur region. The authors wish to thank Dr. Shyam Lal, Physical Research Laboratory Ahmadabad for his constant inspiration and support throughout the programme. Authors express their gratitude to Smt. Anita Koyan (Environmental Engineer), and Dr. Smina CS (Assistant Scientist)of KSPCB for providing support in this study. Resmi expresses her gratitude to Dr. R. Venkatachalam (Principal) and Dr.D. Manivannan (HOD of Physics) of Erode Arts and Science College, Tamil Nadu for providing the necessary facilities and constant support. Prof. Valsaraj thanks the Charles and Hilda Roddey Distinguished Professorship in Chemical Engineering at LSU which supported the preparation of this manuscript. Authors thank the two anonymous reviewers and the Editor for their critical comments/suggestions which have helped us to improve the manuscript in the present form.

References

• Abram, J.P., Creasey, D.J., Heard, D.E., Lee, J.D., Pilling, M.J. (2000) Hydroxyl radical and ozone measurements in England during the solar eclipse of 11 August 1999. Geophysical Research Letters, 27(21), 3437-3440. [https://doi.org/10.1029/2000GL012164]
• Amiridis, V., Melas, D., Balis, D.S., Papayannis, A., Founda, D., Katragkou, E., Giannakaki, E., Mamouri, R.E., Gerasopoulos, E., Zerefos, C. (2007) Aerosol lidar observations and model calculations of planetary boundary layer evolution over Greece during the March 2006 total solar eclipse. Atmospheric Chemistry and Physics, 7, 6181-6189. [https://doi.org/10.5194/acp-7-6181-2007]
• Anderson, J. (1999) Meteorological changes during a solar eclipse. Weather, 54, 207-215. [https://doi.org/10.1002/j.1477-8696.1999.tb06465.x]
• Anfossi, D., Schayes, G., Degrazia, G., Goulart, A. (2004) Atmospheric turbulence decay during the solar total eclipse of 11 August 1999. Boundary layer Meteorology, 111, 301-311. [https://doi.org/10.1023/B:BOUN.0000016491.28111.43]
• Aplin, K.L., Harrison, R.G. (2003) Meteorological effects of the eclipse of 11 August 1999 in cloudy and clear conditions. Proceedings of Royal Society of London, 459, 353-371. [https://doi.org/10.1098/rspa.2002.1042]
• Atkinson, R. (2000) Atmospheric chemistry of VOCs and NO_x. Atmospheric Environment, 34, 2063-2101. [https://doi.org/10.1016/S1352-2310(99)00460-4]
• Beig, G., Gunthe, S., Jadhav, D.B. (2007) Simultaneous measurements of O₃ and its precursors on a diurnal scale at a semi urban site in India. Journal of Atmospheric Chemistry, 57, 239-253. [https://doi.org/10.1007/s10874-007-9068-8]
• Bhat, G.S., Jagannathan, R. (2012) Moisture depletion in the surface layer in response to an annular solar eclipse. Journal of Atmospheric and Solar Terrestrial Physics, 80, 60-67. [https://doi.org/10.1016/j.jastp.2012.02.025]
• Calamas, D.M., Nutter, C., Guajardo, D.N. (2019) Effect of 21 August 2017 solar eclipse on surface-level irradiance and ambient temperature. International Journal of Energy and Environmental Engineering, 10, 147-156. [https://doi.org/10.1007/s40095-018-0290-8]
• Chakrabarty, D.K., Peshin, S.K., Srivastav, S.K., Shah, N.C., Pandya, K.V. (2001) Further evidence of total O₃ variation during the solar eclipse of 1995. Journal of Geophysical Research, 106(D3), 3213-3218. [https://doi.org/10.1029/2000JD900522]
• Chakrabarty, D.K., Shah, N.C., Pandya, K.V. (1997) Fluctuation in column O₃ during the total solar eclipse of 24 October 1995. Journal of Geophysical Research, 24, 3001-3003. [https://doi.org/10.1029/97GL03016]
• Cheng, Y., Ho, K.F., Lee, S.C., Law, S.W. (2006) Seasonal and diurnal variations of PM1.0 PM_2.5 and PM₁₀ in the roadside environment of Hong Kong, China. Particuology, 4, 312-315. [https://doi.org/10.1016/S1672-2515(07)60281-4]
• Chudzynski, S., Czyzewski, A., Ernst, K., Pietruczuk, A., Skubiszak, W., Stacewicz, T., Stelmaszczyk, K., Szymanski, A., Sowka, I., Zwozdziak, A., Zwozdziak, J. (2001) Observation of O₃ concentration during the solar eclipse. Atmospheric Research, 57, 43-49. [https://doi.org/10.1016/S0169-8095(00)00071-5]
• Dolas, P.M., Ramchandra, R., Sen, G.K., Patil, S.M., Jadhav, P.N. (2002) Atmospheric surface-layer processes during the total solar eclipse of 11 August 1999. Boundary Layer Meteorology, 104, 445-461. [https://doi.org/10.1023/A:1016577306546]
• Dutta, D., Kumar, V.P., Ratnam, M.V., Mohammad, S., Kumar, M.C.A., Rao, P.V., Rahaman, K., Basha, H.A. (2011) Response of tropical lower atmosphere to annular solar eclipse of 15 January 2010. Journal of Atmospheric and Solar Terrestrial Physics, 73, 1907-1914. [https://doi.org/10.1016/j.jastp.2011.04.025]
• Eaton, F.D., Hines, J.R., Hatch, W.H., Cionco, R.M., Byer, J., Garvey, D., Miller, D.R. (1997) Solar eclipse effects observed in the planetary boundary layer over a desert. Boundary Layer Meteorology, 83, 331-346. [https://doi.org/10.1023/A:1000219210055]
• Elizabeth, G. (2016) Satellite observations of surface temperature during the March 2015 total solar eclipse. Philosophical Transactions of the Royal Society, 374, 1-16. [https://doi.org/10.1098/rsta.2015.0219]
• Fabian, P., Bernhard, R., Andreas, S., Herbert, W., Martin, W., Hans, S., Paul, S., Harald, B., Uwe, K., Peter, K., Joachim, R., Wolfram, B. (2001) Boundary layer photochemistry during a total solar eclipse. Meteorologische Zeitschrift, 10, 187-192. [https://doi.org/10.1127/0941-2948/2001/0010-0187]
• Fernandez, W., Hidalgo, H., Coronel, G., Morales, E. (1996) Changes in meteorological variables in Coronel Oviedo Paraguay during the total solar eclipse of 3 November 1994. Earth Moon Planet, 74, 49-59. [https://doi.org/10.1007/BF00118721]
• Foken, T., Wichura, B., Klemm, O., Gerchau, J., Winterhalter, M., Weidinger, T. (2001) Micrometeorological measurements during the total solar eclipse of August 11 1999. Meteorologische Zeitschrift, 10, 171-178. [https://doi.org/10.1127/0941-2948/2001/0010-0171]
• Founda, D., Melas, D., Lykoudis, S., Lisaridis, I., Gerasopoulos, E., Kouvarakis, G., Petrakis, M., Zerefos, C. (2007) The effect of the total solar eclipse of 29 March 2006 on meteorological variables in Greece. Atmospheric Chemistry and Physics, 7, 5543-5553. [https://doi.org/10.5194/acp-7-5543-2007]
• Fuglestvedt, J.S., Jonson, J.E., Isaksen, I.S.A. (1994) Effects of reductions in stratospheric Ozone on Tropospheric chemistry through changes in Photolysis Rates. Tellus B: Chemical and Physical Meteorology, 46, 172-192. [https://doi.org/10.1034/j.1600-0889.1992.t01-3-00001.x-i1]
• Gerasopoulos, E., Zerefos, C.S., Tsagouri, I., Founda, D., Amiridis, V., Bais, A.F., Belehaki, A., Christou, N., Economou, G., Kanakidou, M., Karamano, S,A., Petrakis, M., Zanis, P. (2008) The total solar eclipse of March 2006: Overview. Atmospheric Chemistry and Physics, 8, 5205-5220. [https://doi.org/10.5194/acp-8-5205-2008]
• Girach, I.A., Nair, P.R., David, L.M., Hegde, P., Mishra, M.K., Kumar, G.M., Das, S.M., Ojha, N., Naja, M. (2012) The changes in near-surface O₃ and precursors at two nearby tropical sites during annular solar eclipse of 15 January 2010. Journal of Geophysical Research, 117, D01303 [https://doi.org/10.1029/2011JD016521]
• Gorchakov, G.I., Kadygrov, E.N., Kortunova, Z.V., Isakov, A.A., Karpov, A.V., Kopeikin, V.M., Miller, E.A. (2008) Eclipse effects in the atmospheric boundary layer. Izvestiya Atmospheric and Oceanic Physics, 44, 100-106. [https://doi.org/10.1134/S0001433808010118]
• Gröbner, J., Kazadzis, S., Kouremeti, N., Doppler, L., Tagirov, R., Shapiro, A.I. (2017) Spectral solar variations during the eclipse of March 20th 2015 at two European sites AIP Conference Proceedings, 1810, 080008. [https://doi.org/10.1063/1.4975539]
• Hanna, E. (2000) Meteorological effect of the solar eclipse of 11 August 1999. Weather, 55, 430-446. [https://doi.org/10.1002/j.1477-8696.2000.tb06481.x]
• Jokinen, T., Kontkanen, J., Lehtipalo, K., Manninen, H.E., Aalto, J., Castell, A.P., Garmash, O., Nieminen, T., Ehn, M., Kangasluoma, J., Junninen, H., Levula, J., Duplissy, J., Ahonen, L.R., Rantala, P., Heikkinen, L., Yan, C., Sipilä, M., Worsnop, D.R., Bäck, J., Petäjä, T., Kerminen, V.M., Kulmala, M. (2017) Solar eclipse demonstrating the importance of photochemistry in new particle formation. Nature Scientific Reports, 7, 45707. [https://doi.org/10.1038/srep45707]
• Kapoor, R., Adiga, B.B., Singhal, S.P., Aggarwal, S.K., Gera, B.S. (1982) Studies on the atmospheric stability characteristics during the solar eclipse of February 16 1980. Boundary Layer Meteorology, 24, 415-419. [https://doi.org/10.1007/BF00120730]
• Kazadzis, S., Bais, A., Blumthaler, M., Webb, A., Kouremeti1, N., Kift, R., Schallhart, B., Kazantzidis, A. (2007) Effects of solar eclipse of 29 March 2006 on surface radiation. Atmospheric Chemistry and Physics, 7, 5775-5783. [https://doi.org/10.5194/acp-7-5775-2007]
• Kim, H.C., Kim, S., Kim, B.U., Jin, C.S., Hong, S., Park, R., Son, S.W., Bae, C., Bae, M., Song, C.K., Stein, A. (2017) Recent increase of surface particulate matter concentrations in the Seoul Metropolitan Area, Korea. Nature Scientific Report, 7, 4710. [https://doi.org/10.1038/s41598-017-05092-8]
• Kim, S.U., Kim, K.Y. (2020) Physical and chemical mechanisms of the daily-to-seasonal variation of PM₁₀ in Korea. Science of the Total Environment, 712, 136429. [https://doi.org/10.1016/j.scitotenv.2019.136429]
• Koepke, P., Reuder, J., Schween, J. (2001) Spectral variation of the solar radiation during an eclipse. Meteorologische Zeitschrift, 10, 179-186. [https://doi.org/10.1127/0941-2948/2001/0010-0179]
• Kolarz, P., Sekaric, J., Marinkovic, B.P., Filipović, D.M. (2005) Correlation between some of the meteorological parameters measured during the partial solar eclipse 11 August 1999. Journal of Atmospheric and Solar Terrestrial Physics, 67, 1357-1364. [https://doi.org/10.1016/j.jastp.2005.07.016]
• Kostadinov, I., Giovanelli, G., Ravegnani, F., Bortoli, D., Petritili, A. (1999) Depolarization ratio of the zenith scattered radiation and measured NO₂ slant columns. Proceedings of Society of Photo Optical Instrumentation Engineers, 3754, 402-410.
• Krezhova, D.D., Krumov, A.H., Yanev, T.K. (2008) Spectral investigations of the solar radiation during the total solar eclipse on March 29 2006. Journal of Atmospheric and Solar Terrestrial Physics, 70, 365-370. [https://doi.org/10.1016/j.jastp.2007.08.057]
• Krishnan, P., Kunhikrishnan, P.K., Nair, S.M., Ravindran, S., Ramachandran, R., Subrahamanyam, D.B., Ramana, M.V. (2004) Observations of the atmospheric surface layer parameters over a semi-arid region during the solar eclipse of August 11th 1999. Proceedings of Indian Academy of Science, 113, 353-363. [https://doi.org/10.1007/BF02716730]
• Kumar, A., Shukla, D.K., Kumar, A., Sarkar, S.K., Arya, B.C. (2014) Effects of the solar eclipse of 15 January 2010 on direct solar irradiances, surface ozone, NO_x, total ozone column and water vapour observed at Thiruvananthapuram, India. Mausam, 65, 128-136.
• Latha, K.M., Badarinath, K.V.S. (2005) Seasonal variations of PM₁₀ and PM_2.5 particles loading over tropical urban environment. International Journal of Environmental Health Research, 15, 63-68. [https://doi.org/10.1080/09603120400018964]
• Lee, S.C., Chiu, M.Y., Ho, K.F., Zou, S.C., Wang, X. (2002) Volatile organic compounds (VOCs) in urban atmosphere of Hong Kong. Chemosphere, 48, 375-382. [https://doi.org/10.1016/S0045-6535(02)00040-1]
• Liu, S.C., Tranier, M. (1988) Responses of the tropospheric ozone and odd hydrogen radicals to column ozone change. Journal of Atmospheric Chemistry, 6, 221-233. [https://doi.org/10.1007/BF00053857]
• Liu, Z., Hu, B., Wang, L., Wu, F., Gao, W., Wang, Y. (2015) Seasonal and diurnal variation in particulate matter (PM₁₀ and PM_2.5) at an urban site of Beijing: analyses from a 9-year study. Environmental Science and Pollution Research, 22, 627-642. [https://doi.org/10.1007/s11356-014-3347-0]
• Madronich, S., Flocke, S. (1999) The role of solar radiation in atmospheric chemistry. The Handbook of Environmental Chemistry- Environmental Photochemistry, Boule P (Ed), Springer-Verlag Berlin Heidelberg, 2, 1-26. [https://doi.org/10.1007/978-3-540-69044-3_1]
• Madronich, S., Granier, C. (1992) Impact of recent total ozone changes on tropospheric ozone photodissociation, hydroxyl radicals, and methane trends. Geophysical Research Letters, 19, 465-467. [https://doi.org/10.1029/92GL00378]
• Mahapatra, P.S., Panda, S., Walvekar, P.P., Kumar, R., Das, T., Gurjar, B.R. (2014) Seasonal trends meteorological impacts and associated health risks with atmospheric concentrations of gaseous pollutants at an Indian coastal city. Environmental Science and Pollution Research, 21, 11418-11432. [https://doi.org/10.1007/s11356-014-3078-2]
• Manchanda, R.K., Sinha, P.R., Sreenivasan, S., Trivedi, D.B., Kapardhi, B.V.N., Kumar, B.S., Kumar, P.R., Satyaprakash, U., Rao, V.N. (2012) In-situ measurements of vertical structure of O₃ during the solar eclipse of 15 January 2010. Journal of Atmospheric and Solar Terrestrial Physics, 84, 88-100. [https://doi.org/10.1016/j.jastp.2012.05.011]
• Manohar, G.K., Kandalgaonkar, S.S., Kulkarni, M.K. (1995) Impact of a total solar eclipse on surface atmospheric electricity. Journal of Geophysical Research, 100, 20805-20814. [https://doi.org/10.1029/95JD01295]
• Margitan, J.J. (1984) Mechanism of the atmospheric oxidation of Sulfur dioxide catalysis by hydroxyl radicals. Journal of Physical Chemistry, 88, 3314-3318. [https://doi.org/10.1021/j150659a035]
• Miao, Y., Liu, S. (2019) Linkages between aerosol pollution and planetary boundary layer structure in China. Science of the Total Environment, 650, 288-296. [https://doi.org/10.1016/j.scitotenv.2018.09.032]
• Mims III, F.M., Mims, E.R. (1993) Fluctuation in column O₃ during the total solar eclipse of July 11 1991. Journal of Geophysical Research, 20, 367-370. [https://doi.org/10.1029/93GL00493]
• Muraleedharan, P.M., Nisha, P.G., Mohankumar, K. (2011) Effect of January 15 2010 annular solar eclipse on meteorological parameters over Goa India. Journal of Atmospheric and Solar Terrestrial Physics, 73, 1988-1998. [https://doi.org/10.1016/j.jastp.2011.06.003]
• Nair, P.R., Ajayakumar, R.S., David, L.M., Girach, I.A., Mottungan, K. (2018) Decadal changes in surface ozone at the tropical station Thiruvananthapuram (8.542°N, 76.858°E), India: Effects of anthropogenic activities and meteorological variability. Environmental Science and Pollution Research, 25, 14827-14843. [https://doi.org/10.1007/s11356-018-1695-x]
• Naja, M., Lal, S. (1997) Solar eclipse induced changes in surface O₃ at Ahmedabad. Indian Journal of Radio and Space Physics, 26, 312-318.
• Naja, M., Lal, S. (2002) Surface O₃ and precursor gases at Gadanki (135°N 792°E) a tropical rural site in India. Journal of Geophysical Research, 107(D14), 1-13. [https://doi.org/10.1029/2001JD000357]
• Namboodiri, K.V.S., Dileep, P.K., Mammen, K., Ramkumar, G., Kumar, K.N.V.P., Sreenivasan, S., Kumar, S.B., Manchanda., R.K. (2011) Effects of annular solar eclipse of 15 January 2010 on meteorological parameters in the 0 to 65 km region over Thumba India. Meteorologische Zeitschrif, 20, 635-647. [https://doi.org/10.1127/0941-2948/2011/0253]
• Nishanth, T., Ojha, N., Kumar, M.K.S., Naja, M. (2011) Influence of solar eclipse of 15 January 2010 on surface O₃. Atmospheric Environment, 45, 1752-1758. [https://doi.org/10.1016/j.atmosenv.2010.12.034]
• Nishanth, T., Praseed, K.M., Kumar, M.K.S., Valsaraj, K.T. (2014) Influence of ozone precursors and PM₁₀ on the variation of surface O₃ over Kannur India. Atmospheric Research, 138, 112-124. [https://doi.org/10.1016/j.atmosres.2013.10.022]
• Nymphas, E.F., Adeniyi, M.O., Ayoola, M.A., Oladiran, E.O. (2009) Micrometeorological measurements in Nigeria during the total solar eclipse of 29 March 2006. Journal of Atmospheric and Solar Terrestrial Physics, 71, 1245-1253. [https://doi.org/10.1016/j.jastp.2009.04.014]
• Praveena, K., Kunhikrishnan, P.K., Nair, S.M., Sudha, R., Radhika, R., Subrahamanyam, D.B., Ramana, M.V. (2004) Observations of the atmospheric surface layer parameters over a semi-arid region during the solar eclipse of August 11th 1999. Proceedings of Indian Academy of Science, 113, 353-363. [https://doi.org/10.1007/BF02716730]
• Prenosil, T. (2000) The influence of the 11 August 1999 total solar eclipse on the weather over central Europe. Meteorologische Zeitschrift, 9, 351-359. [https://doi.org/10.1127/metz/9/2000/351]
• Raman, S. (1982) Dynamics of the atmospheric boundary layer during the 1980 total solar eclipse. Proceedings of Indian National Science Academy, 48, 187-195.
• Ratnam, M.V., Kumar, M.S., Basha, G., Anandan, V.K., Jayaraman, A. (2010) Effect of the annular solar eclipse of 15 January 2010 on the lower atmospheric boundary layer over a tropical rural station. Journal of Atmospheric and Solar Terrestrial Physics, 72, 1393-1400. [https://doi.org/10.1016/j.jastp.2010.10.009]
• Reddy, K.K., Naja, M., Ojha, N., Mahesh, P., Lal, S. (2012) Influences of the boundary layer evolution on surface O₃ variations at a tropical rural site in India. Journal of Earth System Science, 121, 911-922. [https://doi.org/10.1007/s12040-012-0200-z]
• Sahu, L.K., Saxena, P. (2015) High time and mass resolved PTR-TOF-MS measurements of VOC’s at an urban site of India during winter: role of anthropogenic biomass burning biogenic and photochemical sources. Atmospheric Research, 164, 84-94. [https://doi.org/10.1016/j.atmosres.2015.04.021]
• Segal, M., Turner, R.W., Prusa, J., Bitzer, J.R., Finley, S.V. (1996) Solar eclipse effect on shelter air temperature. Bulletin of American Meteorological Society, 77, 89-99. [https://doi.org/10.1175/1520-0477(1996)077<0089:SEEOSA>2.0.CO;2]
• Seinfeld, J.H., Pandis, S.N. (2006) Atmospheric chemistry and Physics from air pollution to climate change. John Wiley and Sons New York.
• Sethuraman, S. (1982) Dynamics of the atmospheric boundary layer during the 1980 total solar eclipse. Proceedings of INSA Bulletin, 48, 187-195.
• Sharma, S.K., Mandal, T.K., Arya, B.C., Saxena, M., Shukla, D.K., Mukherjee, A., Bhatnagar, R.P., Nath, S., Yadav, S., Gautam, R., Saud, T. (2010) Effects of solar eclipse on 15 January on the surface O₃, NO, NO₂, NH₃, CO mixing ratio and the meteorological parameters at Thiruvananthapuram India. Annales Geophysicae, 28, 1199-1205. [https://doi.org/10.5194/angeo-28-1199-2010]
• Sillman, S. (1995) The use of NO_x, H₂O₂ and HNO₃ as indicators for O₃-NO_x-hydrocarbon sensitivity in urban locations. Journal of Geophysical Research, 100, 14175-14188. [https://doi.org/10.1029/94JD02953]
• Singh, S., Kulshrestha, U.C. (2012) Abundance and distribution of gaseous ammonia and particulate ammonium at Delhi India. Biogeosciences, 9, 5023-5029. [https://doi.org/10.5194/bg-9-5023-2012]
• Singh, S.P., Satsangi, G.S., Khare, P., Kakhani, A., Maharaj, Kumari, M., Srivastava, S.S. (2001) Multiphase measurement of atmospheric ammonia. Chemosphere, 3, 107-116. [https://doi.org/10.1016/S1465-9972(00)00029-5]
• Srimuruganandam, B., Nagendra, S.M.S. (2011) Chemical characterization of PM₁₀ and PM_2.5 mass concentrations emitted by heterogeneous traffic. Science the total Environment, 409, 3144-3157. [https://doi.org/10.1016/j.scitotenv.2011.04.042]
• Srivastava, A., Joseph, A.E., Patil, S., More, A., Dixit, R.C., Prakash, M. (2005) Air toxics in ambient air of Delhi. Atmospheric Environment, 39, 59-71. [https://doi.org/10.1016/j.atmosenv.2004.09.053]
• Srivastava, G.P., Pakkir, M.P.M., Balwalli, R.R. (1982) O₃ concentration measurements near the ground at Raichur during the solar eclipse of 1980. Proceedings of Indian Academy of Science, 48, 138-142.
• Stoev, A., Stoeva, P., Valev, D., Kiskinova, N., Tasheva, T. (2005) Dynamics of the microclimatic parameters of the ground atmospheric layer during the total solar eclipse on August 11 1999. Geophysical Research Abstracts, 7, 10209.
• Subrahamanyam, D.B., Anurose, T.J., Mohan, M., Santosh, M., Kumar, K., Kumar, N.V.P., Sijikumar, S. (2012) Impact of annular solar eclipse of 15 January 2010 on the atmospheric boundary layer characteristics over Thumba: a case study. Pure and Applied Geophysics, 169, 741-753. [https://doi.org/10.1007/s00024-011-0336-9]
• Subrahamanyam, K.V., Ramkumar, G., Kumar, K.K., Swain, D., Kumar, S.V.S., Das, S.S., Choudhary, R.K., Namboodiri, K.V.S., Uma, K.N., Veena, S.B., John, S.R., Babu, A. (2011) Temperature perturbation in the troposphere-stratosphere at Trivandrum during the solar eclipse 2009/2010. Annales Geophysicae, 29, 275-282. [https://doi.org/10.5194/angeo-29-275-2011]
• Szalowski, K. (2002) The effect of the solar eclipse on air temperature near the ground. Journal of Atmospheric and Solar Terrestrial Physics, 64, 1589-1600. [https://doi.org/10.1016/S1364-6826(02)00134-7]
• Tiwari, V., Hanai, Y., Masunaga, S. (2010) Ambient levels of volatile organic compounds in the vicinity of petrochemical industrial area of Yokohama Japan. Air Quality Atmosphere and Health, 3, 65-75. [https://doi.org/10.1007/s11869-009-0052-0]
• Torre, H.L.M., Hernandez, R.M., Domínguez, A.M. (2015) Diurnal and seasonal variation of volatile organic compounds in the atmosphere of Monterrey Mexico. Atmospheric Pollution Research, 6, 1073-1081. [https://doi.org/10.1016/j.apr.2015.06.004]
• Tyagi, S., Tiwari, S., Mishra, A., Hopke, P.K., Attri, S.D., Srivastava, A.K., Bisht, D.S. (2016) Spatial variability of concentrations of gaseous pollutants across the national capital region of Delhi India. Atmospheric Pollution Research, 7(5), 808-816. [https://doi.org/10.1016/j.apr.2016.04.008]
• Tzanis, C. (2005) Ground-based observations of O₃ at Athens Greece during the solar eclipse of 1999. International Journal of Remote Sensing, 26, 3585-3596. [https://doi.org/10.1080/01431160500076947]
• Tzanis, C., Varotsos, C., Viras, L. (2008) Impacts of the solar eclipse of 29 March 2006 on the surface O₃ concentration the solar ultraviolet radiation and the meteorological parameters at Athens Greece. Atmospheric Chemistry and Physics, 7, 425-430. [https://doi.org/10.5194/acp-8-425-2008]
• Verma, N., Satsangi, A., Lakhani, A., Kumari, K.M., Lal, S. (2017) Diurnal Seasonal and Vertical Variability in Carbon Monoxide levels at a Semi-urban Site in India. Clean Soil Air Water, 45, 1600432. [https://doi.org/10.1002/clen.201600432]
• Vogel, B., Baldauf, M., Fiedler, F. (2001) The influence of a solar eclipse on temperature and wind in the Upper-Rhine Valley-A numerical case study. Meteorologische Zeitschrift, 10, 207-214. [https://doi.org/10.1127/0941-2948/2001/0010-0207]
• Vyas, B.M., Saxena, A., Panwar, C. (2012) Study of atmospheric air pollutants during the partial solar eclipse on 15 January 2010 over Udaipur: A semi-arid location in Western India. Advances in Space Research, 50, 1553-1563. [https://doi.org/10.1016/j.asr.2012.07.021]
• Wang, K.Y., Liu, C.H. (2010) Profiles of temperature response to the 22 July 2009 total solar eclipse from FORMASAT-3/COSMIC constellation. Geophysical Research Letters, 37, L01804. [https://doi.org/10.1029/2009GL040968]
• Wang, S., Nan, J., Shi, C., Fu, Q., Gao, S., Wang, D., Cui, H., Lopez, S.A., Zhou, B. (2015) Atmospheric ammonia and its impacts on regional air quality over the megacity of Shanghai China. Nature Scientific Reports, 5, 15842. [https://doi.org/10.1038/srep15842]
• Winkler, P., Kaminski, U., Kohler, U., Riedl, J., Schroers, H., Anwender, D. (2001) Development of meteorological parameters and total O₃ during the total solar eclipse of August 11, 1999. Meteorologische Zeitschrift, 10, 193-199. [https://doi.org/10.1127/0941-2948/2001/0010-0193]
• Yang, Y., Liao, H., Lou, S. (2016) Increase in winter haze over eastern China in recent decades: roles of variations in meteorological parameters and anthropogenic emissions. Journal of Geophysical Research, 121, 13050-13065. [https://doi.org/10.1002/2016JD025136]
• Yassaa, N., Ciccioli, P., Brancaleoni, E., Frattoni, M., Youcef, B.M. (2011) Ambient measurements of selected VOC’s in populated and remote sites of the Sahara desert. Atmospheric Research, 100, 141-146. [https://doi.org/10.1016/j.atmosres.2011.01.001]
• Yurdakul, S., Civan, M., Kuntasal, O., Dogan, G., Pekey, H., Tuncel, G. (2017) Temporal variations of VOC’s concentrations in Bursa atmosphere. Atmospheric Pollution Research, 1-18. [https://doi.org/10.1016/j.apr.2017.09.004]
• Zanis, P., Katragkou, E., Kanakidou, M., Psiloglou, B.E., Karathanasis, S., Vrekoussis, M., Gerasopoulos, E., Markakis, K., Poupkou, A., Amiridis, V., Melas, D., Mihalopoulos, N., Zerefos, C. (2007) Effects on surface atmospheric photo-oxidants over Greece during the total solar eclipse event of 29 March 2006. Atmospheric Chemistry and Physics, 7, 6061-6073. [https://doi.org/10.5194/acp-7-6061-2007]
• Zerefos, C.S., Balis, D.S., Meleti, C., Bais, K., Tourpali, K., Kourtidis, K., Vanicek, K., Cappelani, F., Kaminski, U., Colombo, T., Stubi, R., Manea, L., Formenti, P., Andreae, M.O. (2000) Changes in surface solar UV irradiances and total ozone during the solar eclipse of August 11, 1999. Journal of Geophysical Research, 105(D21), 26463-26473. [https://doi.org/10.1029/2000JD900412]
• Zhao, M., Wang, S., Tan, J., Hua, Y., Wu, D., Hao, J. (2016) Variation of urban atmospheric Ammonia pollution and its relation with PM_2.5 Chemical Property in Winter of Beijing, China. Aerosol and Air Quality Research, 16, 1378-1389. [https://doi.org/10.4209/aaqr.2015.12.0699]