Limitations in our knowledge of the Sun’s variability and impact on stratospheric ozone

2016 ◽  
Author(s):  
William Thomas Ball
Keyword(s):  
Solar Cycle ◽  
Solar Irradiance ◽  
Stratospheric Ozone ◽  
Standard Solar Model ◽  
Solar Observations ◽  
Surface Climate ◽  
The Standard Model ◽  
The Tropics ◽  
Climate Studies ◽  
Solar Ultraviolet

Changes in the Sun over the 11-year solar cycle modify the amount of ozone in the atmosphere over the tropics above 20 km. It is thought that the temperature change resulting from the induced variations of ozone may lead to an impact on the surface climate. Knowing by how much the solar ultraviolet light changes over the cycle is key to understanding the size of that influence. We provide a new model dataset of solar irradiance variability and compare it to the standard model used in climate studies, and to solar observations. We have shown that our model agrees better with an older instrument observing solar irradiance than the standard solar model for climate, though the two solar models and the older observations display much lower solar cycle variability than more recent observations. We discuss the differences and the uncertainties in the measurements. We also demonstrate that the true effect of solar ultraviolet changes on ozone is highly uncertain. This is important to be aware of since our understanding of the Sun’s impact on climate depends, in part, on getting the solar cycle changes in the ultraviolet correct.

scholarly journals The representation of solar cycle signals in stratospheric ozone. Part II: Analysis of global models

2017 ◽  
Author(s):  
Amanda C. Maycock ◽  
Katja Matthes ◽  
Susann Tegtmeier ◽  
Hauke Schmidt ◽  
Rémi Thiéblemont ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Solar Irradiance ◽  
Climate Models ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Temperature Response ◽  
Solar Variability ◽  
High Latitudes ◽  
Stratospheric Temperature ◽  
The Impact

Abstract. The impact of changes in incoming solar irradiance on stratospheric ozone abundances should be included in climate model simulations to fully capture the atmospheric response to solar variability. This study presents the first systematic comparison of the solar-ozone response (SOR) during the 11 year solar cycle amongst different chemistry-climate models (CCMs) and ozone databases specified in climate models that do not include chemistry. We analyse the SOR in eight CCMs from the WCRP/SPARC Chemistry-Climate Model Initiative (CCMI-1) and compare these with three ozone databases: the Bodeker Scientific database, the SPARC/AC&C database for CMIP5, and the SPARC/CCMI database for CMIP6. The results reveal substantial differences in the representation of the SOR between the CMIP5 and CMIP6 ozone databases. The peak amplitude of theSOR in the upper stratosphere (1–5 hPa) decreases from 5 % to 2 % between the CMIP5 and CMIP6 databases. This difference is because the CMIP5 database was constructed from a regression model fit to satellite observations, whereas the CMIP6 database is constructed from CCM simulations, which use a spectral solar irradiance (SSI) dataset with relatively weak UV forcing. The SOR in the CMIP6 ozone database is therefore implicitly more similar to the SOR in the CCMI-1 models than to the CMIP5 ozone database, which shows a greater resemblance in amplitude and structure to the SOR in the Bodeker database. The latitudinal structure of the annual mean SOR in the CMIP6 ozone database and CCMI-1 models is considerably smoother than in the CMIP5 database, which shows strong gradients in the SOR across the midlatitudes owing to the paucity of observations at high latitudes. The SORs in the CMIP6 ozone database and in the CCMI-1 models show a strong seasonal dependence, including large meridional gradients at mid to high latitudes during winter; such seasonal variations in the SOR are not included in the CMIP5 ozone database. Sensitivity experiments with a global atmospheric model without chemistry (ECHAM6.3) are performed to assess the impact of changes in the representation of the SOR and SSI forcing between CMIP5 and CMIP6. The experiments show that the smaller amplitude of the SOR in the CMIP6 ozone database compared to CMIP5 causes a decrease in the modelled tropical stratospheric temperature response over the solar cycle of up to 0.6 K, or around 50 % of the total amplitude. The changes in the SOR explain most of the difference in the amplitude of the tropical stratospheric temperature response in the case with combined changes in SOR and SSI between CMIP5 and CMIP6. The results emphasise the importance of adequately representing the SOR in climate models to capture the impact of solar variability on the atmosphere. Since a number of limitations in the representation of the SOR in the CMIP5 ozone database have been identified, CMIP6 models without chemistry are encouraged to use the CMIP6 ozone database to capture the climate impacts of solar variability.

scholarly journals Estimating solar ultraviolet irradiance (290-385 nm) by means of the spectral parametric models: SPCTRAL2 and SMARTS2

2000 ◽  
Vol 18 (11) ◽  
pp. 1382-1389 ◽  
Author(s):  
I. Foyo-Moreno ◽  
J. Vida ◽  
F. J. Olmo ◽  
L. Alados-Arboledas
Keyword(s):  
Solar Irradiance ◽  
Biological Effects ◽  
Stratospheric Ozone ◽  
Radiant Energy ◽  
Parametric Models ◽  
Spectral Irradiance ◽  
Atmospheric Composition ◽  
Relevant Variables ◽  
Ultraviolet Irradiance ◽  
Solar Ultraviolet

Abstract. Since the discovery of the ozone depletion in Antarctic and the globally declining trend of stratospheric ozone concentration, public and scientific concern has been raised in the last decades. A very important consequence of this fact is the increased broadband and spectral UV radiation in the environment and the biological effects and heath risks that may take place in the near future. The absence of widespread measurements of this radiometric flux has lead to the development and use of alternative estimation procedures such as the parametric approaches. Parametric models compute the radiant energy using available atmospheric parameters. Some parametric models compute the global solar irradiance at surface level by addition of its direct beam and diffuse components. In the present work, we have developed a comparison between two cloudless sky parametrization schemes. Both methods provide an estimation of the solar spectral irradiance that can be integrated spectrally within the limits of interest. For this test we have used data recorded in a radiometric station located at Granada (37.180°N, 3.580°W, 660 m a.m.s.l.), an inland location. The database includes hourly values of the relevant variables covering the years 1994-95. The performance of the models has been tested in relation to their predictive capability of global solar irradiance in the UV range (290–385 nm). After our study, it appears that information concerning the aerosol radiative effects is fundamental in order to obtain a good estimation. The original version of SPCTRAL2 provides estimates of the experimental values with negligible mean bias deviation. This suggests not only the appropriateness of the model but also the convenience of the aerosol features fixed in it to Granada conditions. SMARTS2 model offers increased flexibility concerning the selection of different aerosol models included in the code and provides the best results when the selected models are those considered as urban. Although SMARTS2 provide slightly worse results, both models give estimates of solar ultraviolet irradiance with mean bias deviation below 5%, and root mean square deviation close to experimental errors.Key words: Atmospheric composition and structure (transmission and scattering of radiation) - Meteorology and atmospheric dynamics (radiative process)

scholarly journals Episode of unusual high solar ultraviolet radiation in central Europe due to dynamical reduced stratospheric ozone in May 2005

2005 ◽  
Vol 5 (5) ◽  
pp. 10409-10420 ◽  
Author(s):  
C. Stick ◽  
K. Krüger ◽  
N. H. Schade ◽  
H. Sandmann ◽  
A. Macke
Keyword(s):  
Ultraviolet Radiation ◽  
Uv Radiation ◽  
Stratospheric Ozone ◽  
Solar Ultraviolet Radiation ◽  
Solar Uv ◽  
Resultant Increase ◽  
The Tropics ◽  
Effective Radiation ◽  
Ozone Episodes ◽  
Solar Ultraviolet

Abstract. In late May this year unusual high levels of solar ultraviolet radiation were observed in 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 the high solar elevation angles during late spring leading to the highest value of erythemal UV-radiation ever observed at this location in May. This ''ozone mini-hole'' was caused by an elevation of tropopause height accompanied with a poleward advection of natural low total ozone from the tropics. The resultant increase in UV-radiation is of particular significance for human health. Dynamically induced low ozone episodes that happen around the summer solstice can considerably enhance the solar UV-radiation in the mid latitudes and therefore contribute to the UV-burden of people living in the mid latitudes.

scholarly journals Anthropogenic changes in the surface all-sky UV-B radiation through 1850–2005 simulated by an Earth system model

2012 ◽  
Vol 12 (11) ◽  
pp. 5249-5257 ◽  
Author(s):  
S. Watanabe ◽  
T. Takemura ◽  
K. Sudo ◽  
T. Yokohata ◽  
H. Kawase
Keyword(s):  
Lower Stratosphere ◽  
Stratospheric Ozone ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Total Change ◽  
Anthropogenic Changes ◽  
Ozone Transport ◽  
The Tropics ◽  
Solar Ultraviolet

Abstract. The historical anthropogenic change in the surface all-sky UV-B (solar ultraviolet: 280–315 nm) radiation through 1850–2005 is evaluated using an Earth system model. Responses of UV-B dose to anthropogenic changes in ozone and aerosols are separately evaluated using a series of historical simulations including/excluding these changes. Increases in these air pollutants cause reductions in UV-B transmittance, which occur gradually/rapidly before/after 1950 in and downwind of industrial and deforestation regions. Furthermore, changes in ozone transport in the lower stratosphere, which is induced by increasing greenhouse gas concentrations, increase ozone concentration in the extratropical upper troposphere and lower stratosphere. These transient changes work to decrease the amount of UV-B reaching the Earth's surface, counteracting the well-known effect increasing UV-B due to stratospheric ozone depletion, which developed rapidly after ca. 1980. As a consequence, the surface UV-B radiation change between 1850 and 2000 is negative in the tropics and NH extratropics and positive in the SH extratropics. Comparing the contributions of ozone and aerosol changes to the UV-B change, the transient change in ozone absorption of UV-B mainly determines the total change in the surface UV-B radiation at most locations. On the other hand, the aerosol direct and indirect effects on UV-B play an equally important role to that of ozone in the NH mid-latitudes and tropics. A typical example is East Asia (25° N–60° N and 120° E–150° E), where the effect of aerosols (ca. 70%) dominates the total UV-B change.

scholarly journals Stratospheric Ozone Response to Sulfate Aerosol and Solar Dimming Climate Interventions based on the G6 Geoengineering Model Intercomparison Project (GeoMIP) Simulations

2021 ◽  
Author(s):  
Simone Tilmes ◽  
Daniele Visioni ◽  
Andy Jones ◽  
James Haywood ◽  
Roland Séférian ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Stratospheric Ozone ◽  
Sulfate Aerosol ◽  
Model Intercomparison ◽  
Total Column Ozone ◽  
Surface Climate ◽  
Intercomparison Project ◽  
Column Ozone ◽  
The Tropics ◽  
Earth System Models

Abstract. This study assesses the impacts of sulfate aerosol intervention (SAI) and solar dimming on stratospheric ozone based on the G6 Geoengineering Model Intercomparison Project (GeoMIP) experiments, called G6sulfur and G6solar. For G6sulfur the stratospheric sulfate aerosol burden is increased to reflect some of the incoming solar radiation back into space in order to cool the surface climate, while for G6solar the global solar constant is reduced to achieve the same goal. The high emissions scenario SSP5-8.5 is used as the baseline experiment and surface temperature from the medium emission scenario SSP2-4.5 is the target. Based on three out of six Earth System Models (ESMs) that include interactive stratospheric chemistry, we find significant differences in the ozone distribution between G6solar and G6sulfur experiments compared to SSP5-8.5 and SSP2-4.5, which differ by both region and season. Both SAI and solar dimming methods reduce incoming solar insolation and result in tropospheric temperatures comparable to SSP2-4.5 conditions. G6sulfur increases the concentration of absorbing sulfate aerosols in the stratosphere, which increases lower tropical stratospheric temperatures by between 5 to 13 K for six different ESMs, leading to changes in stratospheric transport. The increase of the aerosol burden also increases aerosol surface area density, which is important for heterogeneous chemical reactions. The resulting changes in ozone include a significant reduction of total column ozone (TCO) in the Southern Hemisphere polar region in October of 10 DU at the onset and up to 20 DU by the end of the century. The relatively small reduction in TCO for the multi-model mean in the first two decades results from variations in the required sulfur injections in the models and differences in the complexity of the chemistry schemes, with no significant ozone loss for 2 out of 3 models. The decrease in the second half of the 21st century counters increasing TCO between SSP2-4.5 and SSP5-8.5 due to the super-recovery resulting from increasing greenhouse gases. In contrast, in the Northern Hemisphere (NH) high latitudes, only a small initial decline in TCO is simulated, with little change in TCO by the end of the century compared to SSP5-8.5. All models consistently simulate an increase in TCO in the NH mid-latitudes up to 20 DU compared to SSP5-8.5, in addition to 20 DU increase resulting from increasing greenhouse gases between SSP2-4.5 and SSP5-8.5. G6solar counters zonal wind and tropical upwelling changes between SSP2-4.5 and SSP5-8.5 but does not change stratospheric temperatures. Solar dimming results in little change in TCO compared to SSP5-8.5 and does not counter the effects of the ozone super-recovery. Only in the tropics, G6solar results in an increase of TCO of up to 8 DU compared to SSP2-4.5, which may counter the projected reduction due to climate change in the high forcing future scenario. This work identifies differences in the response of SAI and solar dimming on ozone, which are at least partly due to differences and shortcomings in the complexity of aerosol microphysics, chemistry, and the description of ozone photolysis in the models. It also identifies that solar dimming, if viewed as an analog to SAI using a predominantly scattering aerosol, would, for the most part, not counter the potential harmful increase in TCO beyond historical values induced by increasing greenhouse gases.

scholarly journals Stratospheric Temperature Trends over 1979–2015 Derived from Combined SSU, MLS, and SABER Satellite Observations

2016 ◽  
Vol 29 (13) ◽  
pp. 4843-4859 ◽  
Author(s):  
William J. Randel ◽  
Anne K. Smith ◽  
Fei Wu ◽  
Cheng-Zhi Zou ◽  
Haifeng Qian
Keyword(s):  
Solar Cycle ◽  
Lower Stratosphere ◽  
Stratospheric Ozone ◽  
Volcanic Eruptions ◽  
Weighting Functions ◽  
Stratospheric Temperature ◽  
Temperature Trends ◽  
Decadal Scale ◽  
Data Record ◽  
The Tropics

Abstract Temperature trends in the middle and upper stratosphere are evaluated using measurements from the Stratospheric Sounding Unit (SSU), combined with data from the Aura Microwave Limb Sounder (MLS) and Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) instruments. Data from MLS and SABER are vertically integrated to approximate the SSU weighting functions and combined with SSU to provide a data record spanning 1979–2015. Vertical integrals are calculated using empirically derived Gaussian weighting functions, which provide improved agreement with high-latitude SSU measurements compared to previously derived weighting functions. These merged SSU data are used to evaluate decadal-scale trends, solar cycle variations, and volcanic effects from the lower to the upper stratosphere. Episodic warming is observed following the volcanic eruptions of El Chichón (1982) and Mt. Pinatubo (1991), focused in the tropics in the lower stratosphere and in high latitudes in the middle and upper stratosphere. Solar cycle variations are centered in the tropics, increasing in amplitude from the lower to the upper stratosphere. Linear trends over 1979–2015 show that cooling increases with altitude from the lower stratosphere (from ~−0.1 to −0.2 K decade−1) to the middle and upper stratosphere (from ~−0.5 to −0.6 K decade−1). Cooling in the middle and upper stratosphere is relatively uniform in latitudes north of about 30°S, but trends decrease to near zero over the Antarctic. Mid- and upper-stratospheric temperatures show larger cooling over the first half of the data record (1979–97) compared to the second half (1998–2015), reflecting differences in upper-stratospheric ozone trends between these periods.

scholarly journals Anthropogenic changes in the surface all-sky UV-B radiation through 1850–2005 simulated by an Earth system model

2012 ◽  
Vol 12 (2) ◽  
pp. 4221-4242
Author(s):  
S. Watanabe ◽  
T. Takemura ◽  
K. Sudo ◽  
T. Yokohata ◽  
H. Kawase
Keyword(s):  
Lower Stratosphere ◽  
Stratospheric Ozone ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Total Change ◽  
Anthropogenic Changes ◽  
Ozone Transport ◽  
The Tropics ◽  
Solar Ultraviolet

Abstract. The historical anthropogenic change in the surface all-sky UV-B (solar ultraviolet: 280–315 nm) radiation through 1850–2005 is evaluated using an Earth system model. Responses of UV-B dose to anthropogenic changes in ozone and aerosols are separately evaluated using a series of historical simulations including/excluding these changes. Increases in these air pollutants cause reductions in UV-B transmittance, which occur gradually/rapidly before/after 1950 in and downwind of industrial and deforestation regions. Furthermore, changes in ozone transport in the lower stratosphere, which is induced by increasing greenhouse gas concentrations, increase ozone concentration in the extratropical upper troposphere and lower stratosphere. These transient changes work to decrease the amount of UV-B reaching the Earth's surface, counteracting the well-known effect increasing UV-B due to stratospheric ozone depletion, which developed rapidly after ca. 1980. As a consequence, the surface all-sky UV-B radiation change between 1850 and 2000 is negative in the tropics and NH extratropics and positive in the SH extratropics. Comparing the contributions of ozone and aerosol changes to the UV-B change, the transient change in ozone absorption of UV-B mainly determines the total change in the surface all-sky UV-B radiation at most locations. On the other hand, the aerosol direct and indirect effects on UV-B play an equally important role to that of ozone in the NH mid-latitudes and tropics. A typical example is East Asia (25° N–60° N and 120° E–150° E), where the effect of aerosols (ca. 70%) dominates the total UV-B change.

scholarly journals The Toba supervolcano eruption caused severe tropical stratospheric ozone depletion

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Sergey Osipov ◽  
Georgiy Stenchikov ◽  
Kostas Tsigaridis ◽  
Allegra N. LeGrande ◽  
Susanne E. Bauer ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Water Cycle ◽  
Stratospheric Ozone ◽  
System Model ◽  
Earth System ◽  
Sulfate Aerosols ◽  
Winter Conditions ◽  
Attenuation Mechanism ◽  
The Tropics ◽  
Sulfur Emissions

AbstractSupervolcano eruptions have occurred throughout Earth’s history and have major environmental impacts. These impacts are mostly associated with the attenuation of visible sunlight by stratospheric sulfate aerosols, which causes cooling and deceleration of the water cycle. Supereruptions have been assumed to cause so-called volcanic winters that act as primary evolutionary factors through ecosystem disruption and famine, however, winter conditions alone may not be sufficient to cause such disruption. Here we use Earth system model simulations to show that stratospheric sulfur emissions from the Toba supereruption 74,000 years ago caused severe stratospheric ozone loss through a radiation attenuation mechanism that only moderately depends on the emission magnitude. The Toba plume strongly inhibited oxygen photolysis, suppressing ozone formation in the tropics, where exceptionally depleted ozone conditions persisted for over a year. This effect, when combined with volcanic winter in the extra-tropics, can account for the impacts of supereruptions on ecosystems and humanity.

Middle Atmosphere Temperature Changes Derived from SABER Observations during 2002-2020

2021 ◽  
pp. 1
Author(s):  
X. R. Zhao ◽  
Z. Sheng ◽  
H. Q. Shi ◽  
L. B. Weng ◽  
Y. He
Keyword(s):  
Solar Cycle ◽  
Middle Atmosphere ◽  
Southern Oscillation ◽  
Linear Trend ◽  
Stratospheric Ozone ◽  
Recovery Period ◽  
Lower Thermosphere ◽  
Quasi Biennial Oscillation ◽  
Atmosphere Temperature ◽  
Temperature Responses

AbstractUsing temperature data measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument from February 2002 to March 2020, the temperature linear trend and temperature responses to the solar cycle (SC), Quasi-Biennial Oscillation (QBO), and El Niño-Southern Oscillation (ENSO) were investigated from 20 km to 110 km for the latitude range of 50°S-50°N. A four-component harmonic fit was used to remove the seasonal variation from the observed monthly temperature series. Multiple linear regression (MLR) was applied to analyze the linear trend, SC, QBO, and ENSO terms. In this study, the near-global mean temperature shows consistent cooling trends throughout the entire middle atmosphere, ranging from -0.28 to -0.97 K/decade. Additionally, it shows positive responses to the solar cycle, varying from -0.05 to 4.53 K/100sfu. A solar temperature response boundary between 50°S and 50°N is given, above which the atmospheric temperature is strongly affected by solar activity. The boundary penetrates deep below the stratopause to ~ 42 km over the tropical region and rises to higher altitudes with latitude. Temperature responses to the QBO and ENSO can be observed up to the upper mesosphere and lower thermosphere. In the equatorial region, 40%-70% of the total variance is explained by QBO signals in the stratosphere and 30%-50% is explained by the solar signal in the upper middle atmosphere. Our results, obtained from 18-year SABER observations, are expected to be an updated reliable estimation of the middle atmosphere temperature variability for the stratospheric ozone recovery period.

scholarly journals Influence of Arctic Stratospheric Ozone on Surface Climate in CCMI models

2018 ◽  
Author(s):  
Ohad Harari ◽  
Chaim I. Garfinkel ◽  
Olaf Morgenstern ◽  
Guang Zeng ◽  
Simone Tilmes ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Climate Model ◽  
Southern Oscillation ◽  
Stratospheric Ozone ◽  
Internal Variability ◽  
Tropical Circulation ◽  
Polar Cap ◽  
Sea Level Pressure ◽  
Surface Climate ◽  
Stratospheric Variability

Abstract. The Northern Hemisphere and tropical circulation response to interannual variability in Arctic stratospheric ozone is analyzed in a set of the latest model simulations archived for the Chemistry-Climate Model Initiative (CCMI) project. All models simulate a connection between ozone variability and temperature/geopotential height in the lower stratosphere similar to that observed. A connection between Arctic ozone variability and polar cap sea-level pressure is also found, but additional analysis suggests that it is mediated by the dynamical variability that typically drives the anomalous ozone concentrations. The CCMI models also show a connection between Arctic stratospheric ozone and the El Nino Southern Oscillation (ENSO): the CCMI models show a tendency of Arctic stratospheric ozone variability to lead ENSO variability one to two years later. While this effect is much weaker than that observed, it is still statistically significant. Overall, Arctic stratospheric ozone is related to lower stratospheric variability and may also influence the surface in both polar and tropical latitudes, though these impacts can be masked by internal variability if data is only available for ~ 40 years.

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