The 11-year solar cycle in stratospheric ozone: Comparison between Umkehr and SBUVv8 and effects on surface erythemal irradiance (original) (raw)
Related papers
Journal of Geophysical Research, 1996
Within the past year, two papers have been published which present updated profile ozone trends from the recently revised ground-based Umkehr record and the combined Nimbus 7 solar backscattered ultraviolet (SBUV) and NOAA 11 SBUV 2 satellite data record . In this paper we compare the ozone trends and responses to the 11-year solar cycle (represented by the F10.7 cm radio flux) derived from these two data sets for the period June 1977 to June 1991 (November 1978 to June 1991 for the satellite data). We consider data at northern midlatitudes (30 ø-50øN) at altitudes between 25 and 45 km derived from these two data sets. In particular, we investigate the effects of spatial sampling differences between the data sets on the derived signals. The trends derived from the two independent data sets are nearly identical at all levels except 35 km, where the Umkehr data indicate a somewhat more negative trend. The trend is approximately zero near 25 km but becomes more negative in the upper stratosphere, reaching nearly -7% per decade in the 40-45 km region. The upper stratospheric decreases are consistent with model results and are associated with the gas-phase chemical effect of chlorofluorocarbons CFC's and other ozone-destroying chemicals [World Meteorological Organization, 1995]. The ozone correlations in the two data sets with the F10.7 cm solar flux are similar, with near-zero solar-induced ozone variations in the 25-30 km region and statistically significant in-phase variations at higher altitudes. Estimates of the solar cycle in the ozone time series at 40-45 km from a regression model indicate variations of about 4.5% from solar cycle maximum to minimum. Analysis of the satellite overpass data at the Umkehr station locations shows that the average of the data from the 11 Umkehr stations is a good approximation for the 30ø-50øN zonal mean.
Journal of Geophysical Research, 2006
1] Previous multiple regression analyses of the solar cycle variation of stratospheric ozone are improved by (1) analyzing three independent satellite ozone data sets with lengths extending up to 25 years and (2) comparing column ozone measurements with ozone profile data during the 1992-2003 period when no major volcanic eruptions occurred. Results show that the vertical structure of the tropical ozone solar cycle response has been consistently characterized by statistically significant positive responses in the upper and lower stratosphere and by statistically insignificant responses in the middle stratosphere ($28-38 km altitude). This vertical structure differs from that predicted by most models. The similar vertical structure in the tropics obtained for separate time intervals (with minimum response invariably near 10 hPa) is difficult to explain by random interference from the QBO and volcanic eruptions in the statistical analysis. The observed increase in tropical total column ozone approaching the cycle 23 maximum during the late 1990s occurred primarily in the lower stratosphere below the 30 hPa level. A mainly dynamical origin for the solar cycle total ozone variation at low latitudes is therefore likely. The amplitude of the solar cycle ozone variation in the tropical upper stratosphere derived here is somewhat reduced in comparison to earlier results. Additional data are needed to determine whether this upper stratospheric response is or is not larger than model estimates. Citation: Soukharev, B. E., and L. L. Hood (2006), Solar cycle variation of stratospheric ozone: Multiple regression analysis of longterm satellite data sets and comparisons with models,
Decadal solar effects on temperature and ozone in the tropical stratosphere
Annales Geophysicae, 2006
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.
Long-term response of stratospheric ozone and temperature to solar variability
Annales Geophysicae, 2015
The long-term variability in stratospheric ozone mass mixing ratio (O 3) and temperature (T) from 1979 to 2013 is investigated using the latest reanalysis product delivered by the European Centre for Medium-Range Weather Forecasts (ECMWF), i.e., ERA-Interim. Moreover, using the Mg II index time series for the same time period, the response of the stratosphere to the 11-year Schwabe solar cycle is investigated. Results reveal the following features: (i) upward (downward) trends characterize zonally averaged O 3 anomalies in the upper (middle to lower stratosphere) stratosphere, while prevailing downward trends affect the T field. Mg II index data exhibit a weaker 24th solar cycle (though not complete) when compared with the previous two; (ii) correlations between O 3 and Mg II, T and Mg II, and O 3 and T are consistent with photochemical reactions occurring in the stratosphere and large-scale transport; and (iii) wavelet cross-spectra between O 3 and Mg II index show common power for the 11-year period, particularly in tropical regions around 30-50 hPa, and different relative phase in the upper and lower stratosphere. A comprehensive insight into the actual processes accounting for the observed correlation between ozone and solar UV variability would be gained from an improved bias correction of ozone measurements provided by different satellite instruments, and from the observations of the time behavior of the solar spectral irradiance.
The Middle Atmospheric Ozone Response to the 11-Year Solar Cycle
Space Science Reviews, 2007
Because of its chemical and radiative properties, atmospheric ozone constitutes a key element of the Earth's climate system. Absorption of sunlight by ozone in the ultraviolet wavelength range is responsible for stratospheric heating, and determines the temperature structure of the middle atmosphere. Changes in middle atmospheric ozone concentrations result in an altered radiative input to the troposphere and to the Earth's surface, with implications on the energy balance and the chemical composition of the lower atmosphere. Although a wide range of ground-and satellite-based measurements of its integrated content and of its vertical distribution have been performed since several decades, a number of uncertainties still remain as to the response of middle atmospheric ozone to changes in solar irradiance over decadal time scales. This paper presents an overview of achieved findings, including a discussion of commonly applied data analysis methods and of their implication for the obtained results. We suggest that because it does not imply least-squares fitting of prescribed periodic or proxy data functions into the considered times series, time-domain analysis provides a more reliable method than multiple regression analysis for extracting decadal-scale signals from observational ozone datasets. Applied to decadal ground-based observations, time-domain analysis indicates an average middle atmospheric ozone increase of the order of 2% from solar minimum to solar maximum, which is in reasonable agreement with model results.
We have used an off-line 3-D chemical transport model (CTM) to investigate the 11-yr solar cycle response in tropical stratospheric ozone. The model is forced with European Centre for Medium-Range Weather Forecasts (ECMWF) (re)analysis (ERA-40/operational and ERA-Interim) data for the 1979-2005 time period. We have compared the modelled solar response in ozone to observationbased data sets that are constructed using satellite instruments such as Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter UltraViolet instrument (SBUV), Stratospheric Aerosol and Gas Experiment (SAGE) and Halogen Occultation Experiment (HALOE). A significant difference is seen between simulated and observed ozone during the 1980s, which is probably due to inhomogeneities in the ERA-40 reanalyses. In general, the model with ERA-Interim dynamics shows better agreement with the observations from 1990 onwards than with ERA-40. Overall both standard model simulations are partially able to simulate a "double peak"-structured ozone solar response with a minimum around 30 km, and these are in better agreement with HALOE than SAGE-corrected SBUV (SBUV/SAGE) or SAGE-based data sets. In the tropical lower stratosphere (TLS), the modelled solar response with time-varying aerosols is amplified through aliasing with a volcanic signal, as the model overestimates ozone loss during high aerosol loading years. However, the modelled solar response with fixed dynamics and constant aerosols shows a positive signal which is in better agreement with SBUV/SAGE and SAGE-based data sets in the TLS. Our model simulations suggests that photochemistry contributes to the ozone solar response in this region. The largest model-observation differences occur in the upper stratosphere where SBUV/SAGE and SAGE-based data show a significant (up to 4 %) solar
Stratospheric Ozone and Surface Ultraviolet Radiation
2011
Global Ozone Observations and Interpretation As a result of the Montreal Protocol, ozone is expected to recover from the effect of ozone-depleting substances (ODSs) as their abundances decline in the coming decades. The 2006 Assessment showed that globally averaged column ozone ceased to decline around 1996, meeting the criterion for the first stage of recovery. Ozone is expected to increase as a result of continued decrease in ODSs (second stage of recovery). This chapter discusses recent observations of ozone and ultraviolet radiation in the context of their historical records. Natural variability, observational uncertainty, and stratospheric cooling necessitate a long record in order to attribute an ozone increase to decreases in ODSs. Table S2-1 summarizes ozone changes since 1980. The primary tools used in this Assessment for prediction of ozone are chemistry-climate models (CCMs). These CCMs are designed to represent the processes determining the amount of stratospheric ozone and its response to changes in ODSs and greenhouse gases. Eighteen CCMs have been recently evaluated using a variety of process-based comparisons to measurements. The CCMs are further evaluated here by comparison of trends calculated from measurements with trends calculated from simulations designed to reproduce ozone behavior during an observing period. Total Column Ozone • Average total ozone values in 2006-2009 have remained at the same level for the past decade, about 3.5% and 2.5% below the 1964-1980 averages respectively for 90°S-90°N and 60°S-60°N. Average total ozone from CCM simulations behaves in a manner similar to observations between 1980 and 2009. The average column ozone for 1964-1980 is chosen as a reference for observed changes for two reasons: 1) reliable ground-based observations sufficient to produce a global average are available in this period; 2) a significant trend is not discernible in the observations during this period. • Southern Hemisphere midlatitude (35°S-60°S) annual mean total column ozone amounts over the period 2006-2009 have remained at the same level as observed during 1996-2005, approximately 6% below the 1964-1980 average. Simulations by CCMs also show declines of the same magnitude between 1980 and 1996, and minimal change after 1996, thus both observations and simulations are consistent with the expectations of the impact of ODSs on southern midlatitude ozone. • Northern Hemisphere midlatitude (35°N-60°N) annual mean total column ozone amounts over the period 2006-2009 have remained at the same level as observed during 1998-2005, approximately 3.5% below the 1964-1980 average. A minimum about 5.5% below the 1964-1980 average was reached in the mid-1990s. Simulations by CCMs agree with these measurements, again showing the consistency of data with the expected impact of ODSs. The simulations also indicate that the minimum in the mid-1990s was primarily caused by the ozone response to effects of volcanic aerosols from the 1991 eruption of Mt. Pinatubo. • The latitude dependence of simulated total column ozone trends generally agrees with that derived from measurements, showing large negative trends at Southern Hemisphere mid and high latitudes and Northern Hemisphere midlatitudes for the period of ODS increase. However, in the tropics the statistically significant range of trends produced by CCMs (−1.5 to −4 Dobson units per decade (DU/decade)) does not agree with the trend obtained from measurements (+0.3 ± 1 DU/decade). Ozone Profiles • Northern Hemisphere midlatitude (35°N-60°N) ozone between 12 and 15 km decreased between 1979 and 1995, and increased between 1996 and 2009. The increase since the mid-1990s is larger than the changes expected from the decline in ODS abundances. Increased by 1 to 2%, but uncertainties are large Southern midlatitudes 1980-1996 Declined by 6% No information Declined by about 7% Declined by about 10% Southern midlatitudes 1996-2009 Remained at approximately the same level No statistically significant changes No statistically significant changes Increased by 1 to 3%, but uncertainties are large 2.3 Stratospheric Ozone and Surface UV Polar Ozone Observations and Interpretation • The Antarctic ozone hole continued to appear each spring from 2006 to 2009. This is expected because decreases in stratospheric chlorine and bromine have been moderate over the last few years. Analysis shows that since 1979 the abundance of total column ozone in the Antarctic ozone hole has evolved in a manner consistent with the time evolution of ODSs. Since about 1997 the ODS amounts have been nearly constant and the depth and magnitude of the ozone hole have been controlled by variations in temperature and dynamics. The October mean column ozone within the vortex has been about 40% below 1980 values for the past fifteen years. • Arctic winter and spring ozone loss has varied between 2007 and 2010, but remained in a range comparable to the values that have prevailed since the early 1990s. Chemical loss of about 80% of the losses observed in the record cold winters of 1999/2000 and 2004/2005 has occurred in recent cold winters. • Recent laboratory measurements of the chlorine monoxide dimer (ClOOCl) dissociation cross section and analyses of observations from aircraft and satellites have reaffirmed the fundamental understanding that polar springtime ozone depletion is caused primarily by the ClO + ClO catalytic ozone destruction cycle, with significant contributions from the BrO + ClO cycle. • Polar stratospheric clouds (PSCs) over Antarctica occur more frequently in early June and less frequently in September than expected based on the previous satellite PSC climatology. This result is obtained from measurements by a new class of satellite instruments that provide daily vortex-wide information concerning PSC composition and occurrence in both hemispheres. The previous satellite PSC climatology was developed from solar occultation instruments that have limited daily coverage. • Calculations constrained to match observed temperatures and halogen levels produce Antarctic ozone losses that are close to those derived from data. Without constraints, CCMs simulate many aspects of the Antarctic ozone hole, however they do not simultaneously produce the cold temperatures, isolation from middle latitudes, deep descent, and high amounts of halogens in the polar vortex. Furthermore, most CCMs underestimate the Arctic ozone loss that is derived from observations, primarily because the simulated northern winter vortices are too warm. Ultraviolet Radiation Ground-based measurements of solar ultraviolet (UV) radiation (wavelength 280-400 nanometers) remain limited both spatially and in duration. However, there have been advances both in reconstructing longer-term UV records from other types of ground-based measurements and in satellite UV retrievals. Where these UV data sets coincide, long-term changes agree, even though there may be differences in instantaneous, absolute levels of UV.
Journal of Geophysical Research, 1997
Within the past few years, several papers have been published which present updated profile ozone trends from the recently revised ground-based Umkehr record and the combined Nimbus 7 solar backscattered ultraviolet (SBUV) and NOAA 11 SBUV 2 satellite data record . Within these papers, however, there has remained an overriding question as to the actual information content of the measurement systems and their ability to detect atmospheric responses. In this paper, we compare the ozone trends and responses to the l 1-year solar cycle (derived from model and/or data specifications of these effects) to results of forward model/retrieval algorithm computations through the algorithms. We consider data at northern midlatitudes (30ø-50øN) so that we may compare the satellite results with those of the ground-based systems. Our results indicate that the Umkehr data contain only four independent pieces of information in the vertical and that the SBUV system contains five. In particular, we find that consideration should be restricted to the following regions; Umkehr: the sum of Umkehr layers 1-5, and layers 6, 7, and 8+ (the sum of layers 8 and above), SBUV: the sum of layers 1-5, and layers 6, 7, 8, and 9+ (the sum of layers 9 and above). Additionally, we compare the actual trends and solar coefficients derived in these layers for the periods 1968-1991 and 1979-1991 for the Umkehr and SBUV data. Finally, we include within the latter comparisons the stratospheric aerosol and gas experiment (SAGE) I and II results from Wang et al. [1996] and the computations from the ozonesondes.
Atmospheric Chemistry and Physics Discussions, 2008
Three analyses of satellite observations and two sets of model studies are used to estimate changes in the stratospheric ozone distribution from solar minimum to solar maximum and are presented for three different latitudinal bands: Poleward of 30 • north, between 30 • north and 30 • south and poleward of 30 • south. In the model studies the 5 solar cycle impact is limited to changes in UV fluxes. There is a general agreement between satellite observation and model studies, particular at middle and high northern latitudes. Ozone increases at solar maximum with peak values around 40 km. The profiles are used to calculate the radiative forcing (RF) from solar minimum to solar maximum. The ozone RF, calculated with two different radiative transfer schemes is 10 found to be negligible (a magnitude of 0.01 Wm −2 or less), compared to the direct RF due to changes in solar irradiance, since contributions from the longwave and shortwave nearly cancel each other. The largest uncertainties in the estimates come from the lower stratosphere, where there is significant disagreement between the different ozone profiles. 15 25 impact of this change in ozone, however, is uncertain. There are significant differences 4354 Abstract 25 (Houghton et al., 2001). Abstract 25 4359 ACPD 8, 4353-4371, 2008 Abstract the lower stratosphere, where ozone perturbations have the strongest impact on the 4360 ACPD 8,[4353][4354][4355][4356][4357][4358][4359][4360][4361][4362][4363][4364][4365][4366][4367][4368][4369][4370][4371] 2008 Abstract 25 extending the calculations down to 20 km has, as expected, more of an effect on the LW forcing, and causes the net forcing to change in sign from negative to positive ; it, however, remains small. 4363 Abstract References Bian, H. S. and Prather, M. J.: Fast-J2: Accurate simulations of stratospheric photolysis in 25 global chemistry models,
The spatial distribution of the association between total ozone and the 11-year solar cycle
Geophys Res Lett, 1992
lh•lr•..•. The pattern of correlation between the l 1year solar cycle and heights and temperatures in the lower stratosphere is in all months shaped as a crescent •th its axis in the subtropics. The change of total ozone from the solar maximum in 1979-1980 to the minimum in 1985-1986 has the same shape. Although the effect of the solar cycle is said to have been removed from the ozone •ta, two thirds of the stations which have been used for •this purpose He outside the regions where the stratosphere is sig•_Jficantly correlated with the solar cycle. For this reason it is unlikely that the influence of the cycle has been completely eliminated. Removal of the Solar Cycle as Described in the WMO Report This note was not written to bring information about the changes in total ozone observed by TOMS, but to point out that the possible influence of the 11-year solar cycle should be sought primarily in the areas where the best correlations between the cycle and stratospheric Mights and temperatures exist. If one uses statiom from areas where there is little or no correlation with the sun in order to eliminate the solar effect, one probably underestimates it. We suggest that such an underestimate • found, for imtance, in a WMO report on the scientific assessment of stratospheric ozone, which shows a map of the difference in annual mean total ozone between the two-year means of 1987-1988 and 1979-1980; that is, between a minimum and a maximum in the ll-year solar cycle (WMO, 1990, Figure 2.2-9a). Our Figure 1 is a similar map for 1985/1986 minus 1979/1980 provided by J. Gille, using TOMS Version 6 data (personal communication). The corresponding two-year differences for 30-rob temperature and geopotential height, which are well hown to be positively correlated with total ozone, are •own in Figures 2 and 3, respectively. The pattern is quite alike in the three figures, with the largest values near 30øN and a dominant zonal asymmetry dose to a wave 1 whose ridge is in the Pacific Sector. Per number 92GL00285 4-8534/92/92GL-00285503.00 The correlation between the mean annual 30-rob height and the l 1-year solar cycle, represented by the 10.7 cm solar flux, has the same crescent-shaped pattern (Figure 4) as that in Figures 1-3 (van Loon and Labitzke, 1990). The 30-rob height is representative of the lower stratosphere, and the pattern in Figure 4 is common to the correlations of 30-rob height with the 10.7 cm flux in all months of the year. With correlations as high as 0.6 -0.7, the time series of the geopotential heights and temperatures resemble the time series of the solar flux; the latter is completely dominated by the 11-year cycle. Examples are shown in van Loon and Labitzke, 1990; Labitzke and van Loon, 1992. We suggest that the ozone changes in Figure 1 and in WMO (1990, Figure 2.2-9) are to some extent still associated with the solar cycle, despite the fact that the WMO (1990) report states the solar cycle has been removed from the data. The wording in the report is that, "In particular, the 10.7 cm flux (F10.7) decreases markedly during the period 1978 through 1986. As a result, initial test calculations showed unacceptably high correlations between total ozone and F10.7. To circumvent this situation, the long-term Dobson record was used to determine the historical relationship between F10.7 and total ozone. This correlation provided a basis for removing the solar effect .... " The Unrepresentativeness of the Stations The twenty-five stations in Figure 4 were used to determine the "historical relationship" between F10.7 and total ozone. Of these only eight lie in the area where the correlation between height and solar cycle in Figure 4 reaches significance at the 1% level (r=0.50). The correlation in Figure 4 is clearly a function of both latitude and longitude; and the European stations in the figure, which play a large role in determining the historical relationship in the WMO report--as well as the North American stations north of about 45øN and half of the Japanese stations --lie in areas of weak or no association with the 10.7 cm solar flux. Consequently, the WMO report arrives at the erroneous conclusion that there is no clear latitudinal dependence on the solar cycle.