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1
Hrabčák, Peter. "Comparison of the optical depth of total ozone and atmospheric aerosols in Poprad-Gánovce, Slovakia." Atmospheric Chemistry and Physics 18, no. 10 (June 1, 2018): 7739–55. http://dx.doi.org/10.5194/acp-18-7739-2018.
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Abstract. The amount of ultraviolet solar radiation reaching the Earth's surface is significantly affected by atmospheric ozone along with aerosols. The present paper is focused on a comparison of the total ozone and atmospheric aerosol optical depth in the area of Poprad-Gánovce, which is situated at the altitude of 706 m a. s. l. in the vicinity of the highest mountain in the Carpathian mountains. The direct solar ultraviolet radiation has been measured here continuously since August 1993 using a Brewer MKIV ozone spectrophotometer. These measurements have been used to calculate the total amount of atmospheric ozone and, subsequently, its optical depth. They have also been used to determine the atmospheric aerosol optical depth (AOD) using the Langley plot method. Results obtained by this method were verified by means of comparison with a method that is part of the Brewer operating software, as well as with measurements made by a Cimel sun photometer. Diffuse radiation, the stray-light effect and polarization corrections were applied to calculate the AOD using the Langley plot method. In this paper, two factors that substantially attenuate the flow of direct ultraviolet solar radiation to the Earth's surface are compared. The paper presents results for 23 years of measurements, namely from 1994 to 2016. Values of optical depth were determined for the wavelengths of 306.3, 310, 313.5, 316.8 and 320 nm. A statistically significant decrease in the total optical depth of the atmosphere was observed with all examined wavelengths. Its root cause is the statistically significant decline in the optical depth of aerosols.
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Stick, C., K. Krüger, N. H. Schade, H. Sandmann, and A. Macke. "Episode of unusual high solar ultraviolet radiation over central Europe due to dynamical reduced total ozone in May 2005." Atmospheric Chemistry and Physics 6, no. 7 (May 29, 2006): 1771–76. http://dx.doi.org/10.5194/acp-6-1771-2006.
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Abstract. In late May 2005 unusual high levels of solar ultraviolet radiation were observed over central Europe. In Northern Germany the measured irradiance of erythemally effective radiation exceeded the climatological mean by more than about 20%. An extreme low ozone event for the season coincided with high solar elevation angles and high pressure induced clear sky conditions leading to the highest value of erythemal UV-radiation ever observed over this location in May since 1994. This hereafter called "ozone mini-hole" was caused by an elevation of tropopause height accompanied with a poleward advection of ozone-poor air from the tropics. The resultant increase in UV-radiation is of particular significance for human health. Dynamically induced low ozone episodes that happen in late spring can considerably enhance the solar UV-radiation in mid latitudes and therefore contribute to the UV-burden of people living in these regions.
3
du Preez, David J., Jelena V. Ajtić, Hassan Bencherif, Nelson Bègue, Jean-Maurice Cadet, and Caradee Y. Wright. "Spring and summer time ozone and solar ultraviolet radiation variations over Cape Point, South Africa." Annales Geophysicae 37, no. 2 (March 6, 2019): 129–41. http://dx.doi.org/10.5194/angeo-37-129-2019.
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Abstract. The correlation between solar ultraviolet radiation (UV) and atmospheric ozone is well understood. Decreased stratospheric ozone levels which led to increased solar UV radiation levels at the surface have been recorded. These increased levels of solar UV radiation have potential negative impacts on public health. This study was done to determine whether the break-up of the Antarctic ozone hole has an impact on stratospheric columnar ozone (SCO) and resulting ambient solar UV-B radiation levels at Cape Point, South Africa, over 2007–2016. We investigated the correlations between UV index, calculated from ground-based solar UV-B radiation measurements and satellite-retrieved column ozone data. The strongest anti-correlation on clear-sky days was found at solar zenith angle 25∘ with exponential fit R2 values of 0.45 and 0.53 for total ozone column and SCO, respectively. An average radiation amplification factor of 0.59 across all SZAs was calculated for clear-sky days. The MIMOSA-CHIM model showed that the polar vortex had a limited effect on ozone levels. Tropical air masses more frequently affect the study site, and this requires further investigation.
4
du Preez, D. Jean, Hassan Bencherif, Thierry Portafaix, Kévin Lamy, and Caradee Yael Wright. "Solar Ultraviolet Radiation in Pretoria and Its Relations to Aerosols and Tropospheric Ozone during the Biomass Burning Season." Atmosphere 12, no. 2 (January 20, 2021): 132. http://dx.doi.org/10.3390/atmos12020132.
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Biomass burning has an impact on atmospheric composition as well as human health and wellbeing. In South Africa, the biomass burning season extends from July to October and affects the aerosol loading and tropospheric ozone concentrations which in turn impact solar ultraviolet radiation (UVR) levels at the surface. Using ground-based observations of aerosols, tropospheric ozone and solar UVR (as well as modelled solar UVR) we investigated the impact of aerosols and tropospheric ozone on solar UVR in August, September, and October over Pretoria. Aerosol optical depth (AOD) and tropospheric ozone reached a peak between September and October each year. On clear-sky days, the average relative difference between the modelled and observed solar Ultraviolet Index (UVI) levels (a standard indicator of surface UVR) at solar noon was 7%. Using modelled UVR—which included and excluded the effects of aerosols and tropospheric ozone from biomass burning—aerosols had a larger radiative effect compared to tropospheric ozone on UVI levels during the biomass burning season. Excluding only aerosols resulted in a 10% difference between the modelled and observed UVI, while excluding only tropospheric ozone resulted in a difference of −2%. Further understanding of the radiative effect of aerosols and trace gases, particularly in regions that are affected by emissions from biomass burning, is considered important for future research.
5
Kazadzis, S., A. Bais, M. Blumthaler, A. Webb, N. Kouremeti, R. Kift, B. Schallhart, and A. Kazantzidis. "Effects of total solar eclipse of 29 March 2006 on surface radiation." Atmospheric Chemistry and Physics 7, no. 22 (November 22, 2007): 5775–83. http://dx.doi.org/10.5194/acp-7-5775-2007.
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Abstract. Solar irradiance spectral measurements were performed during a total solar eclipse. The spectral effect of the limb darkening to the global, direct irradiance and actinic flux measurements was investigated. This effect leads to wavelength dependent changes in the measured solar spectra showing a much more pronounced decrease in the radiation at the lower wavelengths. Radiative transfer model results were used for the computation of a correction for the total ozone measurements due to the limb darkening. This correction was found too small to explain the large decrease in total ozone column derived from the standard Brewer measurements, which is an artifact in the measured irradiance due to the increasing contribution of diffuse radiation against the decreasing direct irradiance caused by the eclipse. Calculations of the Extraterrestrial spectrum and the effective sun's temperatures, as measured from ground based direct irradiance measurements, showed an artificial change in the calculations of both quantities due to the fact that radiation coming from the visible part of the sun during the eclipse phases differs from the black body radiation described by the Planck's law.
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Nowack, Peer Johannes, Nathan Luke Abraham, Peter Braesicke, and John Adrian Pyle. "Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality." Atmospheric Chemistry and Physics 16, no. 6 (March 31, 2016): 4191–203. http://dx.doi.org/10.5194/acp-16-4191-2016.
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Abstract. Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere–ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.
7
Huang, Cong, Fuxiang Huang, Xiaoxin Zhang, Dandan Liu, and Jingtian Lv. "The Contribution of Geomagnetic Activity to Polar Ozone Changes in the Upper Atmosphere." Advances in Meteorology 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/1729454.
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Energetic particle precipitation (EPP) has significant impacts on ozone depletion in the polar middle atmosphere during geomagnetic activity. It is well known that solar ultraviolet (UV) radiation plays an important role in ozone generation. Therefore, it is interesting to compare the contributions of EPP and solar UV to ozone changes in the polar upper atmosphere. In this article, we use the annual average Ap index to denote the annual-mean magnitude of the geomagnetic activity, which is closely correlated with the EPP flux, and the annual average F10.7 index to denote the annual-mean magnitude of the solar radiation, which is somewhat related to the solar UV. We adopt the 5° zonal annual-mean ozone profile dataset to study the statistical characters between the ozone dataset and the Ap, F10.7 indices. Multiple regression analysis shows that the contributions of geomagnetic activity are not negligible and are of a similar order of magnitude as the solar UV radiation in the polar upper atmosphere (above 10 hPa). The results also show that high-speed solar-wind-stream-induced and coronal-mass-ejection-driven geomagnetic activity is of the same order of magnitude. There are interhemispheric differences according to our multiple regression analysis. We discuss the possible causes of these differences.
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Tzanis, C., C. Varotsos, and L. Viras. "Impacts of the solar eclipse of 29 March 2006 on the surface ozone concentration, the solar ultraviolet radiation and the meteorological parameters at Athens, Greece." Atmospheric Chemistry and Physics 8, no. 2 (January 31, 2008): 425–30. http://dx.doi.org/10.5194/acp-8-425-2008.
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Abstract. In this study the variations in the surface ozone concentration, the solar ultraviolet radiation and the meteorological parameters at the ground before, during and after the total solar eclipse of 29 March 2006 have been examined. This analysis is based on the measurements performed at four stations located in the greater Athens basin in Greece. The experimental data demonstrated that the solar eclipse phenomenon affects the surface ozone concentration as well as the temperature, the relative humidity and the wind speed near the ground. The decrease in the surface ozone concentration that observed after the beginning of the eclipse event lasted almost two hours, probably due to the decreased efficiency of the photochemical ozone formation. The reduction of the solar ultraviolet radiation at 312 and 365 nm reached 97% and 93% respectively, while the air temperature dropped, the relative humidity increased and the wind speed decreased.
9
Sinnhuber, B. M., P. von der Gathen, M. Sinnhuber, M. Rex, G. König-Langlo, and S. J. Oltmans. "Large decadal scale changes of polar ozone suggest solar influence." Atmospheric Chemistry and Physics 6, no. 7 (May 29, 2006): 1835–41. http://dx.doi.org/10.5194/acp-6-1835-2006.
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Abstract. Long-term measurements of polar ozone show an unexpectedly large decadal scale variability in the mid-stratosphere during winter. Negative ozone anomalies are strongly correlated with the flux of energetic electrons in the radiation belt, which is modulated by the 11-year solar cycle. The magnitude of the observed decadal ozone changes (≈20%) is much larger than any previously reported solar cycle effect in the atmosphere up to this altitude. The early-winter ozone anomalies subsequently propagate downward into the lower stratosphere and may even influence total ozone and meteorological conditions during spring. These findings suggest a previously unrecognized mechanism by which solar variability impacts on climate through changes in polar ozone.
10
Jackman, C. H., D. R. Marsh, D. E. Kinnison, C. J. Mertens, and E. L. Fleming. "Atmospheric changes caused by galactic cosmic rays over the period 1960–2010." Atmospheric Chemistry and Physics Discussions 15, no. 23 (December 2, 2015): 33931–66. http://dx.doi.org/10.5194/acpd-15-33931-2015.
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Abstract. The Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM) and the Goddard Space Flight Center two-dimensional (GSFC 2-D) models are used to investigate the effect of galactic cosmic rays (GCRs) on the atmosphere over the 1960–2010 time period. The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) computation of the GCR-caused ionization rates are used in these simulations. GCR-caused maximum NOx increases of 4–15 % are computed in the Southern polar troposphere with associated ozone increases of 1–2 %. NOx increases of ∼ 1–6 % are calculated for the lower stratosphere with associated ozone decreases of 0.2–1 %. The primary impact of GCRs on ozone was due to their production of NOx. The impact of GCRs varies with the atmospheric chlorine loading, sulfate aerosol loading, and solar cycle variation. Because of the interference between the NOx and ClOx ozone loss cycles (e.g., the ClO + NO2 + M → ClONO2 + M reaction) and the change in the importance of ClOx in the ozone budget, GCRs cause larger atmospheric impacts with less chlorine loading. GCRs also cause larger atmospheric impacts with less sulfate aerosol loading and for years closer to solar minimum. GCR-caused decreases of annual average global total ozone (AAGTO) were computed to be 0.2 % or less with GCR-caused tropospheric column ozone increases of 0.08 % or less and GCR-caused stratospheric column ozone decreases of 0.23 % or less. Although these computed ozone impacts are small, GCRs provide a natural influence on ozone and need to be quantified over long time periods.
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Rowland, F. Sherwood. "Stratospheric ozone depletion." Philosophical Transactions of the Royal Society B: Biological Sciences 361, no. 1469 (February 21, 2006): 769–90. http://dx.doi.org/10.1098/rstb.2005.1783.
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Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO 2 , NO, NO 2 , Cl and ClO. The NO X and ClO X chains involve the emission at Earth's surface of stable molecules in very low concentration (N 2 O, CCl 2 F 2 , CCl 3 F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290–320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime—the ‘Antarctic ozone hole’. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules.
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Herbst, Konstantin, John Lee Grenfell, Miriam Sinnhuber, Heike Rauer, Bernd Heber, Saša Banjac, Markus Scheucher, et al. "A new model suite to determine the influence of cosmic rays on (exo)planetary atmospheric biosignatures." Astronomy & Astrophysics 631 (October 31, 2019): A101. http://dx.doi.org/10.1051/0004-6361/201935888.
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Context. The first opportunity to detect indications for life outside of the Solar System may be provided already within the next decade with upcoming missions such as the James Webb Space Telescope (JWST), the European Extremely Large Telescope (E-ELT) and the Atmospheric Remote-sensing Infrared Exoplanet Large-survey (ARIEL) mission, searching for atmospheric biosignatures on planets in the habitable zone of cool K- and M-stars. Nevertheless, their harsh stellar radiation and particle environment could lead to photochemical loss of atmospheric biosignatures. Aims. We aim to study the influence of cosmic rays on exoplanetary atmospheric biosignatures and the radiation environment considering feedbacks between energetic particle precipitation, climate, atmospheric ionization, neutral and ion chemistry, and secondary particle generation. Methods. We describe newly combined state-of-the-art modeling tools to study the impact of the radiation and particle environment, in particular of cosmic rays, on atmospheric particle interaction, atmospheric chemistry, and the climate-chemistry coupling in a self-consistent model suite. To this end, models like the Atmospheric Radiation Interaction Simulator (AtRIS), the Exoplanetary Terrestrial Ion Chemistry model (ExoTIC), and the updated coupled climate-chemistry model are combined. Results. In addition to comparing our results to Earth-bound measurements, we investigate the ozone production and -loss cycles as well as the atmospheric radiation dose profiles during quiescent solar periods and during the strong solar energetic particle event of February 23, 1956. Further, the scenario-dependent terrestrial transit spectra, as seen by the NIR-Spec infrared spectrometer onboard the JWST, are modeled. Amongst others, we find that the comparatively weak solar event drastically increases the spectral signal of HNO3, while significantly suppressing the spectral feature of ozone. Because of the slow recovery after such events, the latter indicates that ozone might not be a good biomarker for planets orbiting stars with high flaring rates.
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Xia, Lili, Peer J. Nowack, Simone Tilmes, and Alan Robock. "Impacts of stratospheric sulfate geoengineering on tropospheric ozone." Atmospheric Chemistry and Physics 17, no. 19 (October 9, 2017): 11913–28. http://dx.doi.org/10.5194/acp-17-11913-2017.
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Abstract. A range of solar radiation management (SRM) techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air pollution. In conclusion, surface ozone and tropospheric chemistry would likely be affected by SRM, but the overall effect is strongly dependent on the SRM scheme. Due to the health and economic impacts of surface ozone, all these impacts should be taken into account in evaluations of possible consequences of SRM.
14
Harrison, R. Giles, and Michael Lockwood. "Rapid indirect solar responses observed in the lower atmosphere." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 476, no. 2241 (September 2020): 20200164. http://dx.doi.org/10.1098/rspa.2020.0164.
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Establishing clear evidence of solar-induced lower atmosphere effects is hampered by the small 11-year solar cycle responses, typically swamped by meteorological variability. Strong 27-day cyclic changes are exploited here instead. During the 2007/8 minimum in solar activity, regular 27-day lighthouse-like sweeps of energetic particles crossed the heliosphere and Earth, followed by a burst of solar ultraviolet radiation. Averaging the atmospheric responses at UK sites reveals immediate cooling in the troposphere after the peak energetic particle flux, followed by warming in the stratosphere. Regionally, this is accompanied by zonal wind changes, and temperature changes beneath cloud at the same time. Of two possible rapid distinct routes of solar influence—photochemical (through ozone) and atmospheric electrical (through low level clouds)—the ozone route does not provide a phase-locked response but the electrical route is supported by observed phase-locked thickening of low level clouds. These findings have potential value to weather forecasting.
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Kvalevåg, Maria M., and Gunnar Myhre. "Human Impact on Direct and Diffuse Solar Radiation during the Industrial Era." Journal of Climate 20, no. 19 (October 1, 2007): 4874–83. http://dx.doi.org/10.1175/jcli4277.1.
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Abstract In this study the direct and diffuse solar radiation changes are estimated, and they contribute to the understanding of the observed global dimming and the more recent global brightening during the industrial era. Using a multistream radiative transfer model, the authors calculate the impact of changes in ozone, NO2, water vapor, CH4, CO2, direct and indirect aerosol effects, contrails, and aviation-induced cirrus on solar irradiances at the surface. The results show that dimming is most pronounced in central Africa, Southeast Asia, Europe, and northeast America. Human activity during the industrial era is calculated and accounts for a decrease in direct solar radiation at the surface of up to 30 W m−2 (30%–40%) and an increase in diffuse solar radiation of up to 20 W m−2. The physical processes that lead to the changes in direct and diffuse solar radiation are found to be remarkably different and the authors explain which mechanisms are responsible for the observed changes.
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Jackman, Charles H., Daniel R. Marsh, Douglas E. Kinnison, Christopher J. Mertens, and Eric L. Fleming. "Atmospheric changes caused by galactic cosmic rays over the period 1960–2010." Atmospheric Chemistry and Physics 16, no. 9 (May 13, 2016): 5853–66. http://dx.doi.org/10.5194/acp-16-5853-2016.
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Abstract. The Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM) and the Goddard Space Flight Center two-dimensional (GSFC 2-D) models are used to investigate the effect of galactic cosmic rays (GCRs) on the atmosphere over the 1960–2010 time period. The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) computation of the GCR-caused ionization rates are used in these simulations. GCR-caused maximum NOx increases of 4–15 % are computed in the Southern polar troposphere with associated ozone increases of 1–2 %. NOx increases of ∼ 1–6 % are calculated for the lower stratosphere with associated ozone decreases of 0.2–1 %. The primary impact of GCRs on ozone was due to their production of NOx. The impact of GCRs varies with the atmospheric chlorine loading, sulfate aerosol loading, and solar cycle variation. Because of the interference between the NOx and ClOx ozone loss cycles (e.g., the ClO + NO2+ M → ClONO2+ M reaction) and the change in the importance of ClOx in the ozone budget, GCRs cause larger atmospheric impacts with less chlorine loading. GCRs also cause larger atmospheric impacts with less sulfate aerosol loading and for years closer to solar minimum. GCR-caused decreases of annual average global total ozone (AAGTO) were computed to be 0.2 % or less with GCR-caused column ozone increases between 1000 and 100 hPa of 0.08 % or less and GCR-caused column ozone decreases between 100 and 1 hPa of 0.23 % or less. Although these computed ozone impacts are small, GCRs provide a natural influence on ozone and need to be quantified over long time periods. This result serves as a lower limit because of the use of the ionization model NAIRAS/HZETRN which underestimates the ion production by neglecting electromagnetic and muon branches of the cosmic ray induced cascade. This will be corrected in future works.
17
Nowack, P. J., N. L. Abraham, P. Braesicke, and J. A. Pyle. "Ozone changes under solar geoengineering: implications for UV exposure and air quality." Atmospheric Chemistry and Physics Discussions 15, no. 21 (November 13, 2015): 31973–2004. http://dx.doi.org/10.5194/acpd-15-31973-2015.
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Abstract. Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term Solar Radiation Management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere–ocean coupled climate model, we include atmospheric composition feedbacks such as ozone changes under this scenario. Including the composition changes, we find large reductions in surface UV-B irradiance, with implications for vitamin D production, and increases in surface ozone concentrations, both of which could be important for human health. We highlight that both tropospheric and stratospheric ozone changes should be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.
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Smith, Karen L., Michael Previdi, and Lorenzo M. Polvani. "The Antarctic Atmospheric Energy Budget. Part II: The Effect of Ozone Depletion and its Projected Recovery." Journal of Climate 26, no. 24 (December 2, 2013): 9729–44. http://dx.doi.org/10.1175/jcli-d-13-00173.1.
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Abstract In this study the authors continue their investigation of the atmospheric energy budget of the Antarctic polar cap (the region poleward of 70°S) using integrations of the Whole Atmosphere Community Climate Model from the years 1960 to 2065. In agreement with observational data, it is found that the climatological mean net top-of-atmosphere (TOA) radiative flux is primarily balanced by the horizontal energy flux convergence over the polar cap. On interannual time scales, changes in the net TOA radiative flux are also primarily balanced by changes in the energy flux convergence, with the variability in both terms significantly correlated (positively and negatively, respectively) with the southern annular mode (SAM). On multidecadal time scales, twentieth-century stratospheric ozone depletion produces a negative trend in the net TOA radiative flux due to a decrease in the absorbed solar radiation within the atmosphere–surface column. The negative trend in the net TOA radiative flux is balanced by a positive trend in energy flux convergence, primarily in austral summer. This negative (positive) trend in the net TOA radiation (energy flux convergence) occurs despite a positive trend in the SAM, suggesting that the effects of the SAM on the energy budget are overwhelmed by the direct radiative effects of ozone depletion. In the twenty-first century, ozone recovery is expected to reverse the negative trend in the net TOA radiative flux, which would then, again, be balanced by a decrease in the energy flux convergence. Therefore, over the next several decades, ozone recovery will, in all likelihood, mask the effect of greenhouse gas warming on the Antarctic energy budget.
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Wilson, S. R. "Characterisation of <i>J</i>(O<sup>1</sup>D) at Cape Grim 2000–2005." Atmospheric Chemistry and Physics 15, no. 13 (July 8, 2015): 7337–49. http://dx.doi.org/10.5194/acp-15-7337-2015.
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Abstract. Estimates of the rate of production of excited oxygen atoms due to the photolysis of ozone (J(O1D)) have been derived from radiation measurements carried out at Cape Grim, Tasmania (40.6° S, 144.7° E). The individual measurements have a total uncertainty of 16 % (1σ). These estimates agree well with model estimates of clear-sky photolysis rates. Observations spanning 2000–2005 have been used to quantify the impact of season, clouds and ozone column amount. The annual cycle of J(O1D) has been investigated via monthly means. These means show an interannual variation (monthly standard deviation) of 9 %, but in midsummer and midwinter this reduces to 3–5 %. Variations in solar zenith angle and total column ozone explain 86 % of the observed variability in the measured photolysis rates. The impact of total column ozone, expressed as a radiation amplification factor (RAF), is found to be ~ 1.53, in agreement with model estimates. This ozone dependence explains 20 % of the variation observed at medium solar zenith angles (30–50°). The impact of clouds results in a median reduction of 30 % in J(O1D) for the same solar zenith angle range. Including estimates of cloudiness derived from long-wave radiation measurements resulted in a statistically significant fit to observations, but the quality of the fit did not increase significantly as measured by the adjusted R2.
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Aun, Margit, Kaisa Lakkala, Ricardo Sanchez, Eija Asmi, Fernando Nollas, Outi Meinander, Larisa Sogacheva, et al. "Solar UV radiation measurements in Marambio, Antarctica, during years 2017–2019." Atmospheric Chemistry and Physics 20, no. 10 (May 25, 2020): 6037–54. http://dx.doi.org/10.5194/acp-20-6037-2020.
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Abstract. In March 2017, measurements of downward global irradiance of ultraviolet (UV) radiation were started with a multichannel GUV-2511 radiometer in Marambio, Antarctica (64.23∘ S; 56.62∘ W), by the Finnish Meteorological Institute (FMI) in collaboration with the Servicio Meteorológico Nacional (SMN). These measurements were analysed and the results were compared to previous measurements performed at the same site with the radiometer of the Antarctic NILU-UV network during 2000–2008 and to data from five stations across Antarctica. In 2017/2018 the monthly-average erythemal daily doses from October to January were lower than those averaged over 2000–2008 with differences from 2.3 % to 25.5 %. In 2017/2018 the average daily erythemal dose from September to March was 1.88 kJ m−2, while in 2018/2019 it was 23 % larger (2.37 kJ m−2). Also at several other stations in Antarctica the UV radiation levels in 2017/2018 were below average. The maximum UV indices (UVI) in Marambio were 6.2 and 9.5 in 2017/2018 and 2018/2019, respectively, whereas during years 2000–2008 the maximum was 12. Cloud cover, the strength of the polar vortex and the stratospheric ozone depletion are the primary factors that influence the surface UV radiation levels in Marambio. The lower UV irradiance values in 2017/2018 are explained by the high ozone concentrations in November, February and for a large part of October. The role of cloud cover was clearly seen in December, and to a lesser extent in October and November, when cloud cover qualitatively explains changes which could not be ascribed to changes in total ozone column (TOC). In this study, the roles of aerosols and albedo are of minor influence because the variation of these factors in Marambio was small from one year to the other. The largest variations of UV irradiance occur during spring and early summer when noon solar zenith angle (SZA) is low and the stratospheric ozone concentration is at a minimum (the so-called ozone hole). In 2017/2018, coincident low total ozone column and low cloudiness near solar noon did not occur, and no extreme UV indices were measured.
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Ockenfuß, Paul, Claudia Emde, Bernhard Mayer, and Germar Bernhard. "Accurate 3-D radiative transfer simulation of spectral solar irradiance during the total solar eclipse of 21 August 2017." Atmospheric Chemistry and Physics 20, no. 4 (February 21, 2020): 1961–76. http://dx.doi.org/10.5194/acp-20-1961-2020.
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Abstract. We calculate the variation of spectral solar irradiance in the umbral shadow of the total solar eclipse of 21 August 2017 and compare it to observations. Starting from the Sun's and Moon's positions, we derive a realistic profile of the lunar shadow at the top of the atmosphere, including the effect of solar limb darkening. Subsequently, the Monte Carlo model MYSTIC (Monte Carlo code for the phYSically correct Tracing of photons In Cloudy atmospheres) is used to simulate the transfer of solar radiation through the Earth's atmosphere. Among the effects taken into account are the atmospheric state (pressure, temperature), concentrations of major gas constituents and the curvature of the Earth, as well as the reflectance and elevation of the surrounding area. We apply the model to the total solar eclipse on 21 August 2017 at a position located in Oregon, USA, where irradiance observations were performed for wavelengths between 306 and 1020 nm. The influence of the surface reflectance, the ozone profile, the mountains surrounding the observer and aerosol is investigated. An increased sensitivity during totality is found for the reflectance, aerosol and topography, compared to non-eclipse conditions. During the eclipse, the irradiance at the surface not only depends on the total ozone column (TOC) but also on the vertical ozone distribution, which in general complicates derivations of the TOC from spectral surface irradiance. The findings are related to an analysis of the prevailing photon path and its difference compared to non-eclipse conditions. Using the most realistic estimate for each parameter, the model is compared to the irradiance observations. During totality, the relative difference between model and observations is less than 10 % in the spectral range from 400 to 1020 nm. Slightly larger deviations occur in the ultraviolet range below 400 and at 665 nm.
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Shibata, Kiyotaka. "Simulations of Ozone Feedback Effects on the Equatorial Quasi-Biennial Oscillation with a Chemistry–Climate Model." Climate 9, no. 8 (July 29, 2021): 123. http://dx.doi.org/10.3390/cli9080123.
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Ozone feedback effects on the quasi-biennial oscillation (QBO) were investigated with a chemistry–climate model (CCM) by modifying ozone abundance in the radiative process. Under a standard run for 50 years, the CCM could realistically reproduce the QBO of about a 28-month period for wind and ozone. Five experiment runs were made for 20 years through varying ozone abundance only in the equatorial stratosphere from 100 to 10 hPa by −40, −20, −10, +10, and +20%, respectively, after the chemistry module and transferring the resultant ozone to the radiation calculation. It was found that the modification of ozone abundance in the radiation substantially changed the period of the QBO but slightly influenced the amplitude of the QBO. The 10% and 20% increase runs led to longer QBO periods (31 and 34 months) than that of the standard run, i.e., lengthening by 3 and 6 months, while the 10%, 20%, and 40% decrease runs resulted in shorter periods (24, 22, and 17 months), i.e., shortening by 4, 6, and 11 months. These substantial changes in the QBO period in the experiment runs indicate that the ozone feedback significantly affects the QBO dynamics through the modulation in solar heating.
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Ball, William T., Natalie A. Krivova, Yvonne C. Unruh, Joanna D. Haigh, and Sami K. Solanki. "A New SATIRE-S Spectral Solar Irradiance Reconstruction for Solar Cycles 21–23 and Its Implications for Stratospheric Ozone*." Journal of the Atmospheric Sciences 71, no. 11 (October 29, 2014): 4086–101. http://dx.doi.org/10.1175/jas-d-13-0241.1.
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Abstract The authors present a revised and extended total and spectral solar irradiance (SSI) reconstruction, which includes a wavelength-dependent uncertainty estimate, spanning the last three solar cycles using the Spectral and Total Irradiance Reconstruction—Satellite era (SATIRE-S) model. The SSI reconstruction covers wavelengths between 115 and 160 000 nm and all dates between August 1974 and October 2009. This represents the first full-wavelength SATIRE-S reconstruction to cover the last three solar cycles without data gaps and with an uncertainty estimate. SATIRE-S is compared with the Naval Research Laboratory Spectral Solar Irradiance (NRLSSI) model and ultraviolet (UV) observations from the Solar Radiation and Climate Experiment (SORCE) Solar Stellar Irradiance Comparison Experiment (SOLSTICE). SATIRE-S displays similar cycle behavior to NRLSSI for wavelengths below 242 nm and almost twice the variability between 242 and 310 nm. During the decline of the last solar cycle, between 2003 and 2008, the SSI from SORCE SOLSTICE versions 12 and 10 typically displays more than 3 times the variability of SATIRE-S between 200 and 300 nm. All three datasets are used to model changes in stratospheric ozone within a 2D atmospheric model for a decline from high solar activity to solar minimum. The different flux changes result in different modeled ozone trends. Using NRLSSI leads to a decline in mesospheric ozone, while SATIRE-S and SORCE SOLSTICE result in an increase. Recent publications have highlighted increases in mesospheric ozone when considering version 10 SORCE SOLSTICE irradiances. The recalibrated SORCE SOLSTICE version 12 irradiances result in a much smaller mesospheric ozone response than that of version 10, and this smaller mesospheric ozone response is similar in magnitude to that of SATIRE-S. This shows that current knowledge of variations in spectral irradiance is not sufficient to warrant robust conclusions concerning the impact of solar variability on the atmosphere and climate.
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Perin, S., and D. RS Lean. "The effects of ultraviolet-B radiation on freshwater ecosystems of the Arctic: Influence from stratospheric ozone depletion and climate change." Environmental Reviews 12, no. 1 (March 1, 2004): 1–70. http://dx.doi.org/10.1139/a04-003.
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Depletion of stratospheric ozone, the principal atmospheric attenuator of ultraviolet-B (UVB) radiation, by man-made chemicals has raised scientific and public concern regarding the biological effects of increased UVB radiation on Earth. There is an increased awareness that existing levels of solar UV radiation have an important influence on biological and chemical processes in aquatic ecosystems. For aquatic organisms, numerous studies have shown direct detrimental effects of UVB radiation at each trophic level. Fortunately, many aquatic organisms also possess a range of photoprotective mechanisms against UV radiation toxicity. In addition to its direct impact, harmful effects of UVB radiation at a single-trophic level can cascade through the food web and indirectly affect organisms from other trophic levels. Because UV radiation photochemically reacts with humic substances and other photosensitive agents in the water, increases in solar UVB can also indirectly affect aquatic organisms through the production and (or) release of different photoproducts like biologically available nutrients and harmful reactive oxygen species. Polar aquatic ecosystems have been of particular concern, since stratospheric ozone-related UVB increases have been the greatest in these regions. With the influences of climate warming and the possibility of future volcanic eruptions, ozone losses are expected to get worse in the Arctic stratosphere, and the ozone layer recovery may not follow the slow decline of industrial ozone-depleting compounds in the atmosphere. Climate warming is also expected to bring important changes in underwater ultraviolet radiation (UVR) penetration in Arctic freshwaters that would be more significant to the aquatic biota than stratospheric ozone depletion.Key words: Arctic, UV radiation, UVB, ozone depletion, climate change, aquatic ecosystems.
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Upadhaya, Poojan, Hongbo Du, and Raghava R. Kommalapati. "Meteorological Detrending of Ozone at Three Sites in the Dallas-Fort Worth Area: Application of KZ Filter Method." Atmosphere 11, no. 11 (November 13, 2020): 1226. http://dx.doi.org/10.3390/atmos11111226.
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The Dallas-Fort Worth (DFW) area that experiences high temperature and intense solar radiation falls into the moderate nonattainment classification. The variation in meteorological parameters plays an important role in ambient ozone levels variation. Meteorological influences need to be decoupled from ozone data for long-term trend analysis. Temporal separation of maximum daily average 8-h ozone (MDA8 ozone), maximum daily temperature (TMAX), daily average solar radiation (DASR), and daily average wind speed (DAWS) were conducted using Kolmogorov-Zurbenko (KZ) filter for ozone records at Keller (C17), Arlington (C61), Red Bird (C402) monitoring stations in the DFW area from 2003 to 2017. Temporal separation, regression analysis, and meteorological detrending were performed. The long-term component had a clear and stable trend. The contribution of the long-term component to total variation was negligible, which is less than 2%. This is due to the removal of the data noise from the original time series data. The seasonal component had a major contribution (55% to 72%) in the total variation of the maximum temperature and solar radiation. However, the short-term component was dominant in the total variation of the MDA8 ozone (41–54%) and wind speed (68–79%). Regression analysis showed the baseline component bears the highest correlation than the short-term and raw. Solar radiation had the highest correlation to the MDA8 ozone, followed by temperature data in all three stations. Meteorological detrending showed the detrended long-term ozone had an increasing trend. The increasing trend was significant at C402 with a trend of 0.19 ± 0.006 ppb/y (0.398 R2), whereas slight increasing trends were found at C17 (0.072 ± 0.006 (0.107 R2)) and at C61 (0.019 ± 0.007 (0.005 R2)). The increasing trend of long-term components of MDA8 ozone was justified by the increasing level of NOx and VOCs from the mobile sources in the DFW area.
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Stolarski, Richard S., Anne R. Douglass, Stephen Steenrod, and Steven Pawson. "Trends in Stratospheric Ozone: Lessons Learned from a 3D Chemical Transport Model." Journal of the Atmospheric Sciences 63, no. 3 (March 1, 2006): 1028–41. http://dx.doi.org/10.1175/jas3650.1.
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Abstract Stratospheric ozone is affected by external factors such as chlorofluorcarbons (CFCs), volcanoes, and the 11-yr solar cycle variation of ultraviolet radiation. Dynamical variability due to the quasi-biennial oscillation and other factors also contribute to stratospheric ozone variability. A research focus during the past two decades has been to quantify the downward trend in ozone due to the increase in industrially produced CFCs. During the coming decades research will focus on detection and attribution of the expected recovery of ozone as the CFCs are slowly removed from the atmosphere. A chemical transport model (CTM) has been used to simulate stratospheric composition for the past 30 yr and the next 20 yr using 50 yr of winds and temperatures from a general circulation model (GCM). The simulation includes the solar cycle in ultraviolet radiation, a representation of aerosol surface areas based on observations including volcanic perturbations from El Chichon in 1982 and Pinatubo in 1991, and time-dependent mixing ratio boundary conditions for CFCs, halons, and other source gases such as N2O and CH4. A second CTM simulation was carried out for identical solar flux and boundary conditions but with constant “background” aerosol conditions. The GCM integration included an online ozonelike tracer with specified production and loss that was used to evaluate the effects of interannual variability in dynamics. Statistical time series analysis was applied to both observed and simulated ozone to examine the capability of the analyses for the determination of trends in ozone due to CFCs and to separate these trends from the solar cycle and volcanic effects in the atmosphere. The results point out several difficulties associated with the interpretation of time series analyses of atmospheric ozone data. In particular, it is shown that lengthening the dataset reduces the uncertainty in derived trend due to interannual dynamic variability. It is further shown that interannual variability can make it difficult to accurately assess the impact of a volcanic eruption, such as Pinatubo, on ozone. Such uncertainties make it difficult to obtain an early proof of ozone recovery in response to decreasing chlorine.
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Harde, Hermann. "Radiation Transfer Calculations and Assessment of Global Warming by CO2." International Journal of Atmospheric Sciences 2017 (March 20, 2017): 1–30. http://dx.doi.org/10.1155/2017/9251034.
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We present detailed line-by-line radiation transfer calculations, which were performed under different atmospheric conditions for the most important greenhouse gases water vapor, carbon dioxide, methane, and ozone. Particularly cloud effects, surface temperature variations, and humidity changes as well as molecular lineshape effects are investigated to examine their specific influence on some basic climatologic parameters like the radiative forcing, the long wave absorptivity, and back-radiation as a function of an increasing CO2 concentration in the atmosphere. These calculations are used to assess the CO2 global warming by means of an advanced two-layer climate model and to disclose some larger discrepancies in calculating the climate sensitivity. Including solar and cloud effects as well as all relevant feedback processes our simulations give an equilibrium climate sensitivity of CS = 0.7°C (temperature increase at doubled CO2) and a solar sensitivity of SS = 0.17°C (at 0.1% increase of the total solar irradiance). Then CO2 contributes 40% and the Sun 60% to global warming over the last century.
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Sonkaew, T., V. V. Rozanov, C. von Savigny, A. Rozanov, H. Bovensmann, and J. P. Burrows. "Cloud sensitivity studies for stratospheric and lower mesospheric ozone profile retrievals from measurements of limb-scattered solar radiation." Atmospheric Measurement Techniques 2, no. 2 (November 4, 2009): 653–78. http://dx.doi.org/10.5194/amt-2-653-2009.
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Abstract. Clouds in the atmosphere play an important role in reflection, absorption and transmission of solar radiation and thus affect trace gas retrievals. The main goal of this paper is to examine the sensitivity of stratospheric and lower mesospheric ozone retrievals from limb-scattered radiance measurements to clouds using the SCIATRAN radiative transfer model and retrieval package. The retrieval approach employed is optimal estimation, and the considered clouds are vertically and horizontally homogeneous. Assuming an aerosol-free atmosphere and Mie phase functions for cloud particles, we compute the relative error of ozone profile retrievals in a cloudy atmosphere if clouds are neglected in the retrieval. To access altitudes from the lower stratosphere up to the lower mesosphere, we combine the retrievals in the Chappuis and Hartley ozone absorption bands. We find significant cloud sensitivity of the limb ozone retrievals in the Chappuis bands at lower stratospheric altitudes. The relative error in the retrieved ozone concentrations gradually decreases with increasing altitude and becomes negligible above approximately 40 km. The parameters with the largest impact on the ozone retrievals are cloud optical thickness, ground albedo and solar zenith angle. Clouds with different geometrical thicknesses or different cloud altitudes have a similar impact on the ozone retrievals for a given cloud optical thickness value, if the clouds are outside the field of view of the instrument. The effective radius of water droplets has a small influence on the error, i.e., less than 0.5% at altitudes above the cloud top height. Furthermore, the impact of clouds on the ozone profile retrievals was found to have a rather small dependence on the solar azimuth angle (less than 1% for all possible azimuth angles). For the most frequent cloud types, the total error is below 6% above 15 km altitude, if clouds are completely neglected in the retrieval. Neglecting clouds in the ozone profile retrievals generally leads to a low bias for a low ground albedo and to a high bias for a high ground albedo, assuming that the ground albedo is well known.
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Sonkaew, T., V. V. Rozanov, C. von Savigny, A. Rozanov, H. Bovensmann, and J. P. Burrows. "Cloud sensitivity studies for stratospheric and lower mesospheric ozone profile retrievals from measurements of limb scattered solar radiation." Atmospheric Measurement Techniques Discussions 2, no. 1 (February 24, 2009): 379–438. http://dx.doi.org/10.5194/amtd-2-379-2009.
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Abstract. Clouds in the atmosphere play an important role in reflection, absorption and transmission of solar radiation affecting trace gas retrievals. The main goal of this paper is to examine the sensitivity of stratospheric and lower mesospheric ozone retrievals from limb-scattered radiance measurements to clouds using the SCIATRAN radiative transfer model and retrieval package. Assuming an aerosol-free atmosphere and Mie phase functions for cloud particles, we compute the relative error of ozone profile retrievals in a cloudy atmosphere if clouds are neglected in the retrieval. To access altitudes from the lower stratosphere up to lower mesosphere, we combine the retrievals in the Chappuis and Hartley ozone absorption bands. We find significant cloud sensitivity of the limb ozone retrievals in the Chappuis bands at lower stratospheric altitudes. The relative error in the retrieved ozone concentrations gradually decreases with increasing altitude and becomes negligible above about 40 km. The parameters with the largest impact on the ozone retrievals are cloud optical thickness, ground albedo and solar zenith angle. Clouds with different geometrical thicknesses or different cloud altitudes have a similar impact on the ozone retrievals for a given cloud optical thickness value, if the clouds are outside the field of view of the instrument. The effective radius of water droplets has a small influence on the error, i.e., less than 0.5% at altitudes above the cloud top height. Furthermore, the impact of clouds on the ozone profile retrievals was found to have a rather small dependence on the solar azimuth angle (less than 1% for all possible azimuth angles). For the most frequent cloud types the total error is below 6% above 15 km altitude, if clouds are completely neglected in the retrieval. Neglecting clouds in the ozone profile retrievals generally leads to a low bias for a low ground albedo and to a high bias for a high ground albedo, assuming that the ground albedo is well known.
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Vardavas, I. M., J. H. Carver, and F. W. Taylor. "The role of water-vapour photodissociation on the formation of a deep minimum in mesopause ozone." Annales Geophysicae 16, no. 2 (February 28, 1998): 189–96. http://dx.doi.org/10.1007/s00585-998-0189-4.
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Abstract. A one-dimensional atmospheric photochemical model with an altitude grid of about 1.5 km was used to examine the structure of the global mean vertical ozone profile and its night-time-to-daytime variation in the upper atmosphere. Two distinct ozone layers are predicted, separated by a sharp drop in the ozone concentration near the mesopause. This naturally occurring mesopause ozone deep minimum is primarily produced by the rapid increase in the destruction of water vapour, and hence increase in HOx, at altitudes between 80 and 85 km, a region where water-vapour photodissociation by ultraviolet radiation of the solar Lyman-alpha line is significant, and where the supply of water vapour is maintained by methane oxidation even for very dry conditions at the tropospheric-stratospheric exchange region. The model indicates that the depth of the mesopause ozone minimum is limited by the efficiency with which inactive molecular hydrogen is produced, either by the conversion of atomic hydrogen to molecular hydrogen via one of the reaction channels of H with HO2, or by Lyman-alpha photodissociation of water vapour via the channel that leads to the production of molecular hydrogen. The ozone concentration rapidly recovers above 85 km due to the rapid increase in O produced by the photodissociation of O2 by absorption of ultraviolet solar radiation in the Schumann-Runge bands and continuum. Above 90 km, there is a decrease in ozone due to photolysis as the production of ozone through the three-body recombination of O2 and O becomes slower with decreasing pressure. The model also predicts two peaks in the night-time/daytime ozone ratio, one near 75 km and the other near 110 km, plus a strong peak in the night-time/daytime ratio of OH near 110 km. Recent observational evidence supports the predictions of the model.Key words. Atmospheric composition and structure · Middle atmosphere · Thermosphere · Transmission and scattering of radiation
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Montornès, A., B. Codina, and J. W. Zack. "Analysis of the ozone profile specifications in the WRF-ARW model and their impact on the simulation of direct solar radiation." Atmospheric Chemistry and Physics 15, no. 5 (March 10, 2015): 2693–707. http://dx.doi.org/10.5194/acp-15-2693-2015.
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Abstract. Although ozone is an atmospheric gas with high spatial and temporal variability, mesoscale numerical weather prediction (NWP) models simplify the specification of ozone concentrations used in their shortwave schemes by using a few ozone profiles. In this paper, a two-part study is presented: (i) an evaluation of the quality of the ozone profiles provided for use with the shortwave schemes in the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) model and (ii) an assessment of the impact of deficiencies in those profiles on the performance of model simulations of direct solar radiation. The first part compares simplified data sets used to specify the total ozone column in six schemes (i.e., Goddard, New Goddard, RRTMG, CAM, GFDL and Fu–Liou–Gu) with the Multi-Sensor Reanalysis data set during the period 1979–2008 examining the latitudinal, longitudinal and seasonal limitations in the ozone profile specifications of each parameterization. The results indicate that the maximum deviations are over the poles and show prominent longitudinal patterns in the departures due to the lack of representation of the patterns associated with the Brewer–Dobson circulation and the quasi-stationary features forced by the land–sea distribution, respectively. In the second part, the bias in the simulated direct solar radiation due to these deviations from the simplified spatial and temporal representation of the ozone distribution is analyzed for the New Goddard and CAM schemes using the Beer–Lambert–Bouguer law and for the GFDL using empirical equations. For radiative applications those simplifications introduce spatial and temporal biases with near-zero departures over the tropics throughout the year and increasing poleward with a maximum in the high middle latitudes during the winter of each hemisphere.
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Choon Yeap, Eng, Hwee San Lim, and Zubir Mat Jafri. "Modelling of Solar Spectral Radiation in Penang Island on a Digital Elevation Model." International Journal of Engineering & Technology 7, no. 4.14 (December 24, 2019): 461. http://dx.doi.org/10.14419/ijet.v7i4.14.27719.
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Interest has been increasingly focused on the studies of solar radiation across the globe ever since people are more concern about energy conservation. Due to the increment of terrestrial application of solar energy, the scientific interest on solar distribution has expanded from broadband solar energy to its spectral distribution. Measurement of solar radiation with its spectral profile provides knowledge for making important decisions involving resources and energy, agriculture and climate. In remote sensing, the measurement of spectral solar radiation is important for sensor calibration and image enhancement to extract the most information out of a satellite image. The spectral radiation can be measured using spectral radiometer specifically design for measuring solar radiation; however such instruments are expensive and only provide point data which is very limited in most studies. This study aims to provide a rigorous spectral radiation model that predict the spectral solar irradiance in temporal resolution of every minute with spectral range from 350nm to 2200nm under cloudless condition. The parameters used in this model include the distance between sun and earth, time, coordinate, atmospheric interference and terrain effect. Atmospheric sounding data was used in this study to provide the necessary atmospheric parameter in the simulation of solar propagation through the atmosphere. The atmospheric effects considered in this study include Rayleigh scattering, aerosol attenuation and the absorption of water vapor, ozone and uniformly mixed gas. The simulation results were projected onto a digital elevation model to further calculate the effect introduced by the topographic variation and to get a three dimensional solar spectral radiation. The result obtained from this study is compared with spectral solar irradiance data collected during the month of June and July, 2018 with root mean square deviation of 9 watt per meter square at the wavelength of 350nm to 2200nm.
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Shrestha, P. M., N. P. Chapagain, I. B. Karki, and K. N. Poudyal. "Variation on Atmospheric Transmittance Solar Radiation at Kathmandu Valley." Journal of Nepal Physical Society 6, no. 1 (August 8, 2020): 105–12. http://dx.doi.org/10.3126/jnphyssoc.v6i1.30558.
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The daily solar irradiance was measured using CMP6 first class pyranometer at the horizontal surface of Kathmandu Valley (Lat.:-27.7° N, Long.:-85.5° E, Alt. 1350 m above sea level.) from January to December, 2012 (one year). Monthly mean of atmospheric transmittance is calculated based on different meteorological parameters. The effect of different meteorological parameters as well as physical parameters on the atmospheric transmittance of solar radiation was analyzed. The maximum and the minimum monthly mean solar radiation are found to be 21.32 ± 4.14 MJ/m2/day and 10.93 ± 2.03 MJ/m2/day in May and January, respectively. The value of yearly mean solar radiation measures is 16.68 ± 4.60 MJ/m2/day. Similarly, the annual average of atmospheric transmittance value of 0.51 ± 0.12 was obtained that was due to cloudy and more precipitation day during the months of measurements taken. The yearly mean of atmospheric transmittance 0.983, 0.987, 0.698 and 0.889 are found due to Rayleigh scattering followed by ozone, water vapor, gas mixture and aerosols respectively, the maximum atmospheric transmittance due to water vapor and while minimum due to gas mixture. This research work will be beneficial for the further identification of other affecting factors of different parameters for the interaction with radiation at different places of the country.
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Čížková, Klára, Kamil Láska, Ladislav Metelka, and Martin Staněk. "Reconstruction and analysis of erythemal UV radiation time series from Hradec Králové (Czech Republic) over the past 50 years." Atmospheric Chemistry and Physics 18, no. 3 (February 7, 2018): 1805–18. http://dx.doi.org/10.5194/acp-18-1805-2018.
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Abstract. This paper evaluates the variability of erythemal ultraviolet (EUV) radiation from Hradec Králové (Czech Republic) in the period 1964–2013. The EUV radiation time series was reconstructed using a radiative transfer model and additional empirical relationships, with the final root mean square error of 9.9 %. The reconstructed time series documented the increase in EUV radiation doses in the 1980s and the 1990s (up to 15 % per decade), which was linked to the steep decline in total ozone (10 % per decade). The changes in cloud cover were the major factor affecting the EUV radiation doses especially in the 1960s, 1970s, and at the beginning of the new millennium. The mean annual EUV radiation doses in the decade 2004–2013 declined by 5 %. The factors affecting the EUV radiation doses differed also according to the chosen integration period (daily, monthly, and annually): solar zenith angle was the most important for daily doses, cloud cover, and surface UV albedo for their monthly means, and the annual means of EUV radiation doses were most influenced by total ozone column. The number of days with very high EUV radiation doses increased by 22 % per decade, the increase was statistically significant in all seasons except autumn. The occurrence of the days with very high EUV doses was influenced mostly by low total ozone column (82 % of days), clear-sky or partly cloudy conditions (74 % of days) and by increased surface albedo (19 % of days). The principal component analysis documented that the occurrence of days with very high EUV radiation doses was much affected by the positive phase of North Atlantic Oscillation with an Azores High promontory reaching over central Europe. In the stratosphere, a strong Arctic circumpolar vortex and the meridional inflow of ozone-poor air from the southwest were favorable for the occurrence of days with very high EUV radiation doses. This is the first analysis of the relationship between the high EUV radiation doses and macroscale circulation patterns, and therefore more attention should be given also to other dynamical variables that may affect the solar UV radiation on the Earth surface.
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Kilifarska, Natalya. "Latitudinal dependence of the stratospheric ozone and temperature response to solar particles’ forcing оn 20 January 2005." Aerospace Research in Bulgaria 31 (2019): 5–20. http://dx.doi.org/10.3897/arb.v31.e01.
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This study examines the latitudinal-altitudinal variations of the midday O3and temperature response to the forcing of the enhanced flux of energetic particles, during January 2005 Solar Proton Event (SPE). We show that short-term response of the stratospheric O3 depends strongly on the latitude and the energy of precipitating particles. At polar latitudes, where the relativistic electrons and “soft” protons are able to penetrate deeper into the atmosphere, we found a reduction of the peak ozone density in periods of enhanced particles’ fluxes. Such a response is widely explained by the activation of HOx and NOx ozone destructive cycles. At mid-latitudes, however, the stratospheric part of the O3profile remains insensitive to these lower energy particles, because they affect only the thermospheric and mesospheric O3. On the other hand, the “hard” protons, emitted during the third solar flare on 20 January, are able to propagate much deeper, affecting even the stratospheric ozone and reducing its density. As a consequence of the thinning of the ozone optical depth, the solar UV penetrates deeper into the atmosphere, activating the Slanger’s mechanism for ozone production at lower levels –known also as ozone self-restoration. This could be an explanation for the obtained raise of the mid-latitude peak O3density in the period of atmospheric restoration after the SPE’2005. The earlier raise of the polar ozone maximal density –i.e. between 18 and 21 January –could be related to the fact that at the moment of SPE’2005it has been already diminished by the relativistic electrons and “soft” protons, getting ahead of the strongest proton flare. So the further ozone destruction (by particles with mixed energies) triggered the activation of its restoration several days earlier. Consequently, the latitudinal differences in the ozone response –found in ERA Interim data –could be attributed to the different energetic spectrum of solar flares, the depth of the particles’ penetration into the atmosphere and the zenith angle of stratosphere illumination by the solar UV radiation. Enhancement of the lower and middle stratospheric temperature during the SPE’2005 has to be attributed to the increased ozone density and the more solar UV radiation absorbed.
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Serrano, A., M. Antón, M. L. Cancillo, and J. A. García. "Proposal of a new erythemal UV radiation amplification factor." Atmospheric Chemistry and Physics Discussions 8, no. 1 (January 23, 2008): 1089–111. http://dx.doi.org/10.5194/acpd-8-1089-2008.
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Abstract. This work is aimed to propose a natural expansion of radiation amplification factor (RAF) for erythemal irradiance to consider all solar zenith angles cases together. In this direction, the article analyzes the relationship between measurements of UV erythemal radiation (UVER) recorded at Badajoz (Spain) and the total ozone column estimated by the instrument TOMS/NASA for that location during the period February 2001–December 2005. The new RAF parameter is formulated by power equation using slant ozone and UVER atmospheric transmissivity values. Thus, reliable values of this parameter have been reported. These values could serve as a new relevant index for comparison with other studies and model's result. The new RAF is calculated with measurements recorded during completely clear cases using clearness index values higher than 0.75. The RAF value was 1.35±0.01, it is to say, when the slant ozone amount decreases 1% at Badajoz, UVER atmospheric transmissivity values and, therefore, UVER surface values approximately increase 1.35%. This result emphasizes the interest of measuring and monitoring simultaneous measurements of UV radiation and stratospheric ozone even for mid-latitudes. The influence of total ozone amount and cloudiness changes on new RAF values is analyzed. Cloud-free conditions allow to study the ozone influences while cloud effects are analyzed with all data by means of monthly average of slant ozone and UVER atmospheric transmissivities values.
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Janjai, S., I. Masiri, S. Pattarapanitchai, and J. Laksanaboonsong. "Mapping Global Solar Radiation from Long-Term Satellite Data in the Tropics Using an Improved Model." International Journal of Photoenergy 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/210159.
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This paper presents an improved model and its application for mapping global solar radiation from satellite data in the tropics. The model provides a more complete description of the absorption and scattering of solar radiation in the earth-atmosphere system as compared to the earlier models. The study is conducted in the tropical environment of Thailand. Digital data from the visible channel of GMS4, GMS5, GOES9, and MTSAT-1R satellites collected during a 15-year period (1995–2009) are used as a main input to the model. Satellite gray levels are converted into earth-atmospheric reflectivity and used to estimate the cloud effect. The absorption of solar radiation due to water vapour is computed from precipitable water derived from ambient temperature and relative humidity. The total ozone column data from TOMS/EP and OMI/AURA satellites are used to compute solar radiation absorption by ozone. The depletion of solar radiation due to aerosol is estimated from visibility data. In order to test its performance, the model is employed to calculate monthly average daily global solar radiation at 36 solar monitoring stations across the country. It is found that solar radiation calculated from the model and that obtained from the measurement are in good agreement, with a root mean square difference of 5.3% and a mean bias difference of 0.3%. The model is used to calculate the monthly average daily global solar radiation over the entire country, and results are displayed as monthly and yearly maps. These maps reveal that the geographical distribution of solar radiation in Thailand is strongly influenced by the tropical monsoons and local geographical features.
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Feister, U., J. Junk, M. Woldt, A. Bais, A. Helbig, M. Janouch, W. Josefsson, et al. "Long-term solar UV radiation reconstructed by ANN modelling with emphasis on spatial characteristics of input data." Atmospheric Chemistry and Physics 8, no. 12 (June 23, 2008): 3107–18. http://dx.doi.org/10.5194/acp-8-3107-2008.
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Abstract. Artificial Neural Networks (ANN) are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100 years into the past. Special emphasis will be given to the discussion of small-scale characteristics of input data to the ANN model. Annual totals of UV radiation derived from reconstructed daily UV values reflect interannual variations and long-term patterns that are compatible with variabilities and changes of measured input data, in particular global dimming by about 1980/1990, subsequent global brightening, volcanic eruption effects such as that of Mt. Pinatubo, and the long-term ozone decline since the 1970s. Patterns of annual erythemal UV radiation are very similar at sites located at latitudes close to each other, but different patterns occur between UV radiation at sites in different latitude regions.
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Elias, Ana G. "Lower and middle atmosphere and ozone layer responses to solar variation." Proceedings of the International Astronomical Union 5, S264 (August 2009): 336–42. http://dx.doi.org/10.1017/s1743921309992882.
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AbstractGlobal warming in the troposphere and the decrease of stratospheric ozone concentration has become a major concern to the scientific community. The increase in greenhouse gases and aerosols concentration is believed to be the main cause of this global change in the lower atmosphere and in stratospheric ozone, which is corresponded by a cooling in the middle and upper atmosphere. However, there are natural sources, such as the sun and volcanic eruptions, with the same ability to produce global changes in the atmosphere. The present work will focus on solar variation and its signature in lower and middle atmosphere parameters. The Sun can influence the Earth and its climate through electromagnetic radiation variations and also through changes in the solar wind which causes geomagnetic storms. The effects of both mechanisms over the lower and middle atmosphere and ozone layer will be discussed through an overview of selected papers, which by no means cover this subject that is extremely wide and complex. A fundamental understanding of the atmosphere response to solar variations is required for understanding and interpreting the causes of atmospheric variability. This is an essential focus of climate science, which is seeking to determine the extent to which human activities are altering the planetary energy balance through the emission of greenhouse gases and pollutants.
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Damiani, A., M. Storini, M. Laurenza, and C. Rafanelli. "Solar particle effects on minor components of the Polar atmosphere." Annales Geophysicae 26, no. 2 (February 26, 2008): 361–70. http://dx.doi.org/10.5194/angeo-26-361-2008.
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Abstract. Solar activity can influence the Earth's environment, and in particular the ozone layer, by direct modulation of the e.m. radiation or through variability of the incoming cosmic ray flux (solar and galactic particles). In particular, solar energetic particles (SEPs) provide additional external energy to the terrestrial environment; they are able to interact with the minor constituents of the atmospheric layer and produce ionizations, dissociations, dissociative ionizations and excitations. This paper highlights the SEP effects on the chemistry of the upper atmosphere by analysing some SEP events recorded during 2005 in the descending phase of the current solar cycle. It is shown that these events can lead to short- (hours) and medium- (days) term ozone variations through catalytic cycles (e.g. HOx and NOx increases). We focus attention on the relationship between ozone and OH data (retrieved from MLS EOS AURA) for four SEP events: 17 and 20 January, 15 May and 8 September. We confirm that SEP effects are different on the night and day hemispheres at high latitudes.
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Kalbarczyk, Robert, and Eliza Kalbarczyk. "Ozone concentration in ground-level air layer in north-western Poland - The role of meteorological elements." Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation 41, no. 1 (January 1, 2009): 19–39. http://dx.doi.org/10.2478/v10060-008-0047-9.
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Ozone concentration in ground-level air layer in north-western Poland - The role of meteorological elements The research aimed at recognising time structure and variability of tropospheric ozone as a function of daytime and nocturnal meteorological conditions, particularly in the spring season (March-May), as well as finding a weather cluster at which the highest O3 concentration occurs. Ozone concentrations recorded every hour during the two years and data on five other meteorological elements: total solar radiation, air temperature, relative air humidity, atmospheric pressure, wind direction and speed provided the input data for the analysis. The data were collected at Widuchowa weather station, north-western Poland, near the Polish-German border. The highest ozone concentration was observed at daytime day, under conditions of eastern wind, low relative air humidity (about 35%), high values of total solar radiation (about 209 W·m-2), air temperature (17.0°C), atmospheric pressure (1016 hPa) and high wind speed (2.7 m·s-1). It is concluded that the magnitude of tropospheric ozone concentration recorded at Widuchowa is influenced by gaseous pollutants originating not only from the territory of Poland but also from Germany.
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Delia-Gabriela, Calinoiu, and Paulescu Marius. "Impact of Aerosol on the Estimation Accuracy of Solar Radiation." Annals of West University of Timisoara - Physics 60, no. 1 (August 1, 2018): 97–103. http://dx.doi.org/10.2478/awutp-2018-0010.
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AbstractThe paper is focused on the solar irradiance estimation in clear-sky conditions and an aerosol-loaded atmosphere. Two parametric models developed by our group and three empirical models are tested. The estimates of the parametric models are based on three atmospheric parameters (ozone, nitrogen dioxide and water vapor column content) and the aerosol properties quantified by means of several specific parameters (Ångström turbidity coefficient, single scattering albedo, asymmetry factor). The empirical models contain no inputs for aerosol properties. Data collected from 10 stations were used to test the models. The inputs for the parametric models were retrieved from Aerosol Robotic Network - AERONET. Global and diffuse solar irradiance data at high-quality standards were retrieved from the Baseline Surface Radiation Network BSRN. A comparative analysis of the models’ accuracy in estimating clear-sky solar irradiance is discussed from the perspective of aerosol proprieties.
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Zhang, Zhiming, Jian Rao, Dong Guo, Wenhui Zhang, Liping Li, Zhou Tang, Chunhua Shi, Yucheng Su, and Fuying Zhang. "Interdecadal Variations of the Midlatitude Ozone Valleys in Summer." Atmosphere 10, no. 11 (November 2, 2019): 677. http://dx.doi.org/10.3390/atmos10110677.
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Using the ERA-Interim total column ozone data, the spatial distributions of the long-term mean of the global total ozone in summer are analyzed. The results demonstrate that there are three midlatitude ozone “valleys” on earth—they are centered over the Tibetan Plateau (TIP), the Rocky Mountains (ROM), and the Southwest Pacific (SWP), respectively. The interdecadal variations of the three ozone valleys are positively modulated by the solar radiation, and the TIP ozone’s correlation with the solar radiation gets maximized with a two-year lag. The interdecadal variation of the SWP ozone valley has a significantly negative relationship with the Pacific Decadal Oscillation (PDO) and the South Pacific quadrupole (SPQ). Warm sea surface temperature anomalies (SSTAs) associated with the SPQ strengthen the vertical ascending motion, which dilutes the high concentration ozone at high altitudes. The interdecadal variation of the ROM ozone valley is positively correlated with the PDO, leading by three years. The ROM ozone content is also modulated by SSTAs in the Indian Ocean basin (IOB) by the circumglobal teleconnection (CGT). The observed regional SSTAs can exert a significant impact on the regional and even global circulation, via which the ozone content in midlatitudes also varies.
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Jain, Basanti. "EFFECTS OF GLOBAL WARMING." International Journal of Research -GRANTHAALAYAH 3, no. 9SE (September 30, 2015): 1–2. http://dx.doi.org/10.29121/granthaalayah.v3.i9se.2015.3116.
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The abnormal increase in the concentration of the greenhouse gases is resulting in higher temperatures. We call this effect is global warming. The average temperature around the world has increased about 1'c over 140 years, 75% of this has risen just over the past 30 years.
The solar radiation, as it reaches the earth, produces "greenhouse effect" in the atmosphere. The thick atmospheric layers over the earth behaves as a glass surface, as it permits short wave radiations from coming in, but checks the outgoing long wave ones. As a result, gradually the atmosphere gets heated up during the day as well as night. If such an effect were not there in the atmosphere the ultraviolet, infrared and other ionizing radiations would have also entered our atmosphere and the very existence of life would have been endangered. The ozone layer shields the earth from the sun's harmful ultraviolet radiations. The warm earth emits long wave (infrared) radiations, which is partly absorbed by the green house gaseous blanket. This atmospheric blanket raises the earth’s temperature.
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Bilbao, J., R. Román, C. Yousif, D. Mateos, and A. de Miguel. "UV and global irradiance measurements and analysis during the Marsaxlokk (Malta) campaign." Advances in Science and Research 12, no. 1 (July 9, 2015): 147–55. http://dx.doi.org/10.5194/asr-12-147-2015.
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Abstract. A solar radiation measurement campaign was performed in the south-eastern village of Marsaxlokk (35°50' N; 14°33' E; 10 m a.s.l), Malta, between 15 May and 15 October 2012. Erythemal solar radiation data (from a UVB-1 pyranometer), and total horizontal solar radiation (global and diffuse components) from two CM21 pyranometer were recorded. A comparison of atmospheric compounds from ground measurements and satellites shows that TOC (total ozone column) data from the Ozone Monitoring Instrument OMI, TOMS and DOAS algorithms correlate well with ground-based recorded data. The water vapour column and the aerosol optical depth at 550 nm show a significant correlation at the confidence level of 99 %. Parametric models for evaluating the solar UV erythemal (UVER), global (G) and diffuse (D) horizontal irradiances are calibrated, from which aerosol effects on solar irradiance are evaluated using the Aerosol Modification Factor (AMF). The AMFUVER values are lower than AMFG, indicating a greater aerosol effect on UVER than on global solar irradiance. In this campaign, several dust event trajectories are identified by means of the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and by synoptic conditions for characterizing desert dust events. Hence, changes in the UV index due to atmospheric aerosols are described.
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Feister, U., J. Junk, and M. Woldt. "Long-term solar UV radiation reconstructed by Artificial Neural Networks (ANN)." Atmospheric Chemistry and Physics Discussions 8, no. 1 (January 10, 2008): 453–88. http://dx.doi.org/10.5194/acpd-8-453-2008.
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Abstract. Artificial Neural Networks (ANN) are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100 years into the past. Annual totals of UV radiation derived from reconstructed daily UV values reflect interannual variations and long-term patterns that are compatible with variabilities and changes of measured input data, in particular global dimming by about 1980–1990, subsequent global brightening, volcanic eruption effects such as that of Mt. Pinatubo, and the long-term ozone decline since the 1970s. Patterns of annual erythemal UV radiation are very similar at sites located at latitudes close to each other, but different patterns occur between UV radiation at sites in different latitude regions.
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Fadnavis, S., and G. Beig. "Decadal solar effects on temperature and ozone in the tropical stratosphere." Annales Geophysicae 24, no. 8 (September 13, 2006): 2091–103. http://dx.doi.org/10.5194/angeo-24-2091-2006.
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Abstract. To investigate the effects of decadal solar variability on ozone and temperature in the tropical stratosphere, along with interconnections to other features of the middle atmosphere, simultaneous data obtained from the Halogen Occultation Experiment (HALOE) aboard the Upper Atmospheric Research Satellite (UARS) and the Stratospheric Aerosol and Gas Experiment II (SAGE II) aboard the Earth Radiation Budget Satellite (ERBS) during the period 1992–2004 have been analyzed using a multifunctional regression model. In general, responses of solar signal on temperature and ozone profiles show good agreement for HALOE and SAGE~II measurements. The inferred annual-mean solar effect on temperature is found to be positive in the lower stratosphere (max 1.2±0.5 K / 100 sfu) and near stratopause, while negative in the middle stratosphere. The inferred solar effect on ozone is found to be significant in most of the stratosphere (2±1.1–4±1.6% / 100 sfu). These observed results are in reasonable agreement with model simulations. Solar signals in ozone and temperature are in phase in the lower stratosphere and they are out of phase in the upper stratosphere. These inferred solar effects on ozone and temperature are found to vary dramatically during some months, at least in some altitude regions. Solar effects on temperature are found to be negative from August to March between 9 mb–3 mb pressure levels while solar effects on ozone are maximum during January–March near 10 mb in the Northern Hemisphere and 5 mb–7 mb in the Southern Hemisphere.
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den Outer, P. N., A. van Dijk, H. Slaper, A. V. Lindfors, H. De Backer, A. F. Bais, U. Feister, T. Koskela, and W. Josefsson. "Correcting spaceborne reflectivity measurements for application in solar ultraviolet radiation levels calculations at ground level." Atmospheric Measurement Techniques Discussions 5, no. 1 (January 4, 2012): 61–96. http://dx.doi.org/10.5194/amtd-5-61-2012.
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Abstract. The Lambertian Equivalent Reflection (LER) produced by satellite-carried instruments is used to determine cloud effects on ground level UltraViolet (UV) radiation. The focus is on data use from consecutive operating instruments: the Total Ozone Mapping Spectrometers (TOMS) flown on Nimbus 7 from 1979 to 1992, TOMS on Earth Probe from 1996 to 2005, and the Ozone Monitoring Instrument (OMI) flown on Aura since 2004. The LER data produced by TOMS on Earth Probe is only included until 2002. The possibility to use the Radiative Cloud Fraction (RCF)-product of OMI is also investigated. A comparison is made with cloud effects inferred from ground-based pyranometer measurements at over 83 World Radiation Data Centre stations. Modelled UV irradiances utilizing LER data are compared with measurements of UV irradiances at eight European low elevation stations. The LER data set of the two TOMS instruments shows a consistent agreement, and the required corrections are of low percentage i.e. 2–3%. In contrast, the LER data of OMI requires correction of 7–10%, and a solar angle dependency therein is more pronounced. These corrections were inferred from a comparison with pyranometer data, and tested using the UV measurements. The RCF product of OMI requires a large correction but can then be implemented as a cloud effect proxy. However, a major drawback of RCF is the large number of clipped data, i.e. 18%, and results are not better than those obtained with the corrected LER product of OMI. The average reduction of UV radiation due to clouds for all sites together indicate a small trend: a diminishing cloudiness, in line with ground-based UV observations. Uncorrected implementation of LER would have indicated the opposite. An optimal field of view of 1.25° was established for LER data to calculate UV radiations levels. The corresponding area can be traversed within 5–7 h at the average wind speeds found for the West European continent.
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Yurganov, L. N. "Surface layer ozone above the Weddell Sea during the Antarctic spring." Antarctic Science 2, no. 2 (June 1990): 169–74. http://dx.doi.org/10.1017/s0954102090000220.
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Ozone concentrations in the atmospheric surface layer above the Weddell Sea during the Antarctic spring season of 1989 varied significantly. Lower levels of ozone were associated with colder Antarctic air masses and higher values with warmer mid-latitude air. The lowest ozone concentration (1 to 2 ppbv) was measured in the centre of a low pressure system. A definite diurnal variation of tropospheric ozone observed during clear days with low total ozone amount (177 matm cm) may be interpreted as a consequence of the occurrence of photochemical reactions under conditions of increased ultraviolet solar radiation.
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Vincent, W. F. "Poles together." Antarctic Science 5, no. 4 (December 1993): 333. http://dx.doi.org/10.1017/s0954102093000446.
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In March 1993 the Atmospheric Environment Service's monitoring network across Canada registered ground-level fluxes of solar ultraviolet-B radiation (UVBR) that were the highest on record. This effect was correlated with the spring-time depletion of ozone in the northern upper atmosphere, and AES predicted that the average depletion over Canada could be this severe or worse for the next 15–20 years. These reports heightened awareness amongst the Canadian public as well as the scientific community about the Antarctic ozone hole, and about the most recent UVBR and atmospheric research findings from Antarctica. The causes and biological impacts of high latitude ozone depletion is but one example where information derived from one polar zone is of vital interest to those living in, or otherwise concerned with the other. In this and other research areas the time is appropriate for a bipolar perspective on Antarctica.