scholarly journals Total column ozone retrieval using INSAT-3D sounder in the tropics: A simulation study

2014 ◽  
Vol 123 (6) ◽  
pp. 1265-1271 ◽  
Author(s):  
P Jindal ◽  
P K Thapliyal ◽  
M V Shukla ◽  
A K Mishra ◽  
D Mitra
Keyword(s):  
Simulation Study ◽  
Total Column Ozone ◽  
Column Ozone ◽  
The Tropics ◽  
Total Column

scholarly journals On ozone trend detection: using coupled chemistry–climate simulations to investigate early signs of total column ozone recovery

2018 ◽  
Vol 18 (10) ◽  
pp. 7625-7637 ◽  
Author(s):  
James Keeble ◽  
Hannah Brown ◽  
N. Luke Abraham ◽  
Neil R. P. Harris ◽  
John A. Pyle
Keyword(s):  
Ensemble Member ◽  
Trend Detection ◽  
Large Sample Size ◽  
Total Column Ozone ◽  
Large Variability ◽  
Ozone Trend ◽  
Column Ozone ◽  
The Tropics ◽  
Total Column ◽  
Natural Cycles

Abstract. Total column ozone values from an ensemble of UM-UKCA model simulations are examined to investigate different definitions of progress on the road to ozone recovery. The impacts of modelled internal atmospheric variability are accounted for by applying a multiple linear regression model to modelled total column ozone values, and ozone trend analysis is performed on the resulting ozone residuals. Three definitions of recovery are investigated: (i) a slowed rate of decline and the date of minimum column ozone, (ii) the identification of significant positive trends and (iii) a return to historic values. A return to past thresholds is the last state to be achieved. Minimum column ozone values, averaged from 60° S to 60° N, occur between 1990 and 1995 for each ensemble member, driven in part by the solar minimum conditions during the 1990s. When natural cycles are accounted for, identification of the year of minimum ozone in the resulting ozone residuals is uncertain, with minimum values for each ensemble member occurring at different times between 1992 and 2000. As a result of this large variability, identification of the date of minimum ozone constitutes a poor measure of ozone recovery. Trends for the 2000–2017 period are positive at most latitudes and are statistically significant in the mid-latitudes in both hemispheres when natural cycles are accounted for. This significance results largely from the large sample size of the multi-member ensemble. Significant trends cannot be identified by 2017 at the highest latitudes, due to the large interannual variability in the data, nor in the tropics, due to the small trend magnitude, although it is projected that significant trends may be identified in these regions soon thereafter. While significant positive trends in total column ozone could be identified at all latitudes by ∼ 2030, column ozone values which are lower than the 1980 annual mean can occur in the mid-latitudes until ∼ 2050, and in the tropics and high latitudes deep into the second half of the 21st century.

scholarly journals A new ENSO index derived from satellite measurements of column ozone

2010 ◽  
Vol 10 (8) ◽  
pp. 3711-3721 ◽  
Author(s):  
J. R. Ziemke ◽  
S. Chandra ◽  
L. D. Oman ◽  
P. K. Bhartia
Keyword(s):  
Climate Models ◽  
Southern Oscillation ◽  
Ozone Monitoring Instrument ◽  
Total Column Ozone ◽  
Enso Events ◽  
Gas Measurements ◽  
Column Ozone ◽  
The Tropics ◽  
Total Column ◽  
Enso Index

Abstract. Column Ozone measured in tropical latitudes from Nimbus 7 total ozone mapping spectrometer (TOMS), Earth Probe TOMS, solar backscatter ultraviolet (SBUV), and Aura ozone monitoring instrument (OMI) are used to derive an El Nino-Southern Oscillation (ENSO) index. This index, which covers a time period from 1979 to the present, is defined as the "Ozone ENSO Index" (OEI) and is the first developed from atmospheric trace gas measurements. The OEI is constructed by first averaging monthly mean column ozone over two broad regions in the western and eastern Pacific and then taking their difference. This differencing yields a self-calibrating ENSO index which is independent of individual instrument calibration offsets and drifts in measurements over the long record. The combined Aura OMI and MLS ozone data confirm that zonal variability in total column ozone in the tropics caused by ENSO events lies almost entirely in the troposphere. As a result, the OEI can be derived directly from total column ozone instead of tropospheric column ozone. For clear-sky ozone measurements a +1 K change in Nino 3.4 index corresponds to +2.9 Dobson Unit (DU) change in the OEI, while a +1 hPa change in SOI coincides with a −1.7 DU change in the OEI. For ozone measurements under all cloud conditions these numbers are +2.4 DU and −1.4 DU, respectively. As an ENSO index based upon ozone, it is potentially useful in evaluating climate models predicting long term changes in ozone and other trace gases.

scholarly journals Ozone Variation Trends under Different CMIP6 Scenarios

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 112
Author(s):  
Lin Shang ◽  
Jiali Luo ◽  
Chunxiao Wang
Keyword(s):  
Ozone Concentration ◽  
Radiative Forcing ◽  
Stratospheric Ozone ◽  
Lower Troposphere ◽  
Total Column Ozone ◽  
The Social ◽  
Tropical Troposphere ◽  
Column Ozone ◽  
The Tropics ◽  
Total Column

This study compares and analyzes simulations of ozone under different scenarios by three CMIP6 models (IPSL-CM6A, MRI-ESM2 and CESM-WACCM). Results indicate that as the social vulnerability and anthropogenic radiative forcing is increasing, the change of total column ozone in the tropical stratosphere is not linear. Compared to the SSP2-4.5 and SSP5-8.5 scenarios, the SSP1-2.6 and SSP3-7.0 are more favorable for the increase in stratospheric ozone mass in the tropics. Arctic ozone would never recover under the SSP1-2.6 scenario; however, the Antarctica ozone would gradually recover in all scenarios. Under the SSP1-2.6 and SSP2-4.5 scenarios, the trend of tropical total column ozone is mainly determined by the trend of column ozone in the tropical troposphere. Under the SSP3-7.0 scenario, tropospheric ozone concentration will significantly increase; under the SSP5-8.5 scenario, ozone concentration will distinctly increase in the middle and lower troposphere.

scholarly journals Estimates of ozone return dates from Chemistry-Climate Model Initiative simulations

2018 ◽  
Vol 18 (11) ◽  
pp. 8409-8438 ◽  
Author(s):  
Sandip S. Dhomse ◽  
Douglas Kinnison ◽  
Martyn P. Chipperfield ◽  
Ross J. Salawitch ◽  
Irene Cionni ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Tropospheric Chemistry ◽  
The Arctic ◽  
Total Column Ozone ◽  
Column Ozone ◽  
The Tropics ◽  
The Impact ◽  
Total Column

Abstract. >We analyse simulations performed for the Chemistry-Climate Model Initiative (CCMI) to estimate the return dates of the stratospheric ozone layer from depletion caused by anthropogenic stratospheric chlorine and bromine. We consider a total of 155 simulations from 20 models, including a range of sensitivity studies which examine the impact of climate change on ozone recovery. For the control simulations (unconstrained by nudging towards analysed meteorology) there is a large spread (±20 DU in the global average) in the predictions of the absolute ozone column. Therefore, the model results need to be adjusted for biases against historical data. Also, the interannual variability in the model results need to be smoothed in order to provide a reasonably narrow estimate of the range of ozone return dates. Consistent with previous studies, but here for a Representative Concentration Pathway (RCP) of 6.0, these new CCMI simulations project that global total column ozone will return to 1980 values in 2049 (with a 1σ uncertainty of 2043–2055). At Southern Hemisphere mid-latitudes column ozone is projected to return to 1980 values in 2045 (2039–2050), and at Northern Hemisphere mid-latitudes in 2032 (2020–2044). In the polar regions, the return dates are 2060 (2055–2066) in the Antarctic in October and 2034 (2025–2043) in the Arctic in March. The earlier return dates in the Northern Hemisphere reflect the larger sensitivity to dynamical changes. Our estimates of return dates are later than those presented in the 2014 Ozone Assessment by approximately 5–17 years, depending on the region, with the previous best estimates often falling outside of our uncertainty range. In the tropics only around half the models predict a return of ozone to 1980 values, around 2040, while the other half do not reach the 1980 value. All models show a negative trend in tropical total column ozone towards the end of the 21st century. The CCMI models generally agree in their simulation of the time evolution of stratospheric chlorine and bromine, which are the main drivers of ozone loss and recovery. However, there are a few outliers which show that the multi-model mean results for ozone recovery are not as tightly constrained as possible. Throughout the stratosphere the spread of ozone return dates to 1980 values between models tends to correlate with the spread of the return of inorganic chlorine to 1980 values. In the upper stratosphere, greenhouse gas-induced cooling speeds up the return by about 10–20 years. In the lower stratosphere, and for the column, there is a more direct link in the timing of the return dates of ozone and chlorine, especially for the large Antarctic depletion. Comparisons of total column ozone between the models is affected by different predictions of the evolution of tropospheric ozone within the same scenario, presumably due to differing treatment of tropospheric chemistry. Therefore, for many scenarios, clear conclusions can only be drawn for stratospheric ozone columns rather than the total column. As noted by previous studies, the timing of ozone recovery is affected by the evolution of N2O and CH4. However, quantifying the effect in the simulations analysed here is limited by the few realisations available for these experiments compared to internal model variability. The large increase in N2O given in RCP 6.0 extends the ozone return globally by ∼ 15 years relative to N2O fixed at 1960 abundances, mainly because it allows tropical column ozone to be depleted. The effect in extratropical latitudes is much smaller. The large increase in CH4 given in the RCP 8.5 scenario compared to RCP 6.0 also lengthens ozone return by ∼ 15 years, again mainly through its impact in the tropics. Overall, our estimates of ozone return dates are uncertain due to both uncertainties in future scenarios, in particular those of greenhouse gases, and uncertainties in models. The scenario uncertainty is small in the short term but increases with time, and becomes large by the end of the century. There are still some model–model differences related to well-known processes which affect ozone recovery. Efforts need to continue to ensure that models used for assessment purposes accurately represent stratospheric chemistry and the prescribed scenarios of ozone-depleting substances, and only those models are used to calculate return dates. For future assessments of single forcing or combined effects of CO2, CH4, and N2O on the stratospheric column ozone return dates, this work suggests that it is more important to have multi-member (at least three) ensembles for each scenario from every established participating model, rather than a large number of individual models.

scholarly journals The global overturning diabatic circulation of the stratosphere as a metric for the Brewer-Dobson Circulation

2018 ◽  
Author(s):  
Marianna Linz ◽  
Marta Abalos ◽  
Anne Sasha Glanville ◽  
Douglas E. Kinnison ◽  
Alison Ming ◽  
...  
Keyword(s):  
Time Series ◽  
Water Vapor ◽  
Vertical Velocity ◽  
Recent Theory ◽  
Residual Circulation ◽  
Total Column Ozone ◽  
Upper Level ◽  
Column Ozone ◽  
The Tropics ◽  
Total Column

Abstract. The circulation of the stratosphere, also known as the Brewer-Dobson circulation, transports water vapor and ozone, with implications for radiative forcing and climate. This circulation is typically quantified from model output by calculating the tropical upwelling vertical velocity in the residual circulation framework, and it is estimated from observations by using time series of tropical water vapor to infer a vertical velocity. Recent theory has introduced a method to calculate the global mean diabatic circulation strength through isentropes from satellite measurements of long-lived tracers. In this paper, we explore this global diabatic circulation as it relates to the residual circulation vertical velocity, stratospheric water vapor, and ozone at interannual timescales. We use a comprehensive climate model, three reanalysis data products, and satellite ozone data. The different metrics for the circulation have different properties, especially with regards to the vertical autocorrelation. In the model, the different residual circulation metrics agree closely and are well correlated with the global diabatic circulation, except in the lowermost stratosphere. In the reanalysis products however, there are more differences throughout, indicating the dynamical inconsistencies of these products. The vertical velocity derived from the time series of water vapor in the tropics is significantly correlated with the diabatic circulation, but this relationship is not as strong as that between the diabatic circulation and the residual circulation vertical velocity. We find that the diabatic circulation in the lower to middle stratosphere (up to 500 K) is correlated with the total column ozone in the high latitudes and in the tropics. The upper level circulation is also correlated with the total column ozone, primarily in the subtropics, and we show that this is due to the correlation of both the circulation and the ozone with upper level temperatures.

scholarly journals The global diabatic circulation of the stratosphere as a metric for the Brewer–Dobson circulation

2019 ◽  
Vol 19 (7) ◽  
pp. 5069-5090 ◽  
Author(s):  
Marianna Linz ◽  
Marta Abalos ◽  
Anne Sasha Glanville ◽  
Douglas E. Kinnison ◽  
Alison Ming ◽  
...  
Keyword(s):  
Time Series ◽  
Water Vapor ◽  
Vertical Velocity ◽  
Recent Theory ◽  
Residual Circulation ◽  
Total Column Ozone ◽  
Upper Level ◽  
Column Ozone ◽  
The Tropics ◽  
Total Column

Abstract. The circulation of the stratosphere, also known as the Brewer–Dobson circulation, transports water vapor and ozone, with implications for radiative forcing and climate. This circulation is typically quantified from model output by calculating the tropical upwelling vertical velocity in the residual circulation framework, and it is estimated from observations by using time series of tropical water vapor to infer a vertical velocity. Recent theory has introduced a method to calculate the strength of the global mean diabatic circulation through isentropes from satellite measurements of long-lived tracers. In this paper, we explore this global diabatic circulation as it relates to the residual circulation vertical velocity, stratospheric water vapor, and ozone at interannual timescales. We use a comprehensive climate model, three reanalysis data products, and satellite ozone data. The different metrics for the circulation have different properties, especially with regards to the vertical autocorrelation. In the model, the different residual circulation metrics agree closely and are well correlated with the global diabatic circulation, except in the lowermost stratosphere. In the reanalysis products, however, there are more differences throughout, indicating the dynamical inconsistencies of these products. The vertical velocity derived from the time series of water vapor in the tropics is significantly correlated with the global diabatic circulation, but this relationship is not as strong as that between the global diabatic circulation and the residual circulation vertical velocity. We find that the global diabatic circulation in the lower to middle stratosphere (up to 500 K) is correlated with the total column ozone in the high latitudes and in the tropics. The upper-level circulation is also correlated with the total column ozone, primarily in the subtropics, and we show that this is due to the correlation of both the circulation and the ozone with upper-level temperatures.

scholarly journals A new ENSO index derived from satellite measurements of column ozone

2010 ◽  
Vol 10 (2) ◽  
pp. 2859-2887
Author(s):  
J. R. Ziemke ◽  
S. Chandra ◽  
L. D. Oman ◽  
P. K. Bhartia
Keyword(s):  
Climate Models ◽  
Southern Oscillation ◽  
Data Mining Technique ◽  
Total Column Ozone ◽  
Enso Events ◽  
Gas Measurements ◽  
Column Ozone ◽  
The Tropics ◽  
Total Column ◽  
Enso Index

Abstract. Column Ozone measured in tropical latitudes from Nimbus 7 TOMS, Earth Probe TOMS, NOAA SBUV, and Aura OMI satellite instruments are used to derive an El Niño-Southern Oscillation (ENSO) index. This index, which covers a time period from 1979 to the present, is defined as the Ozone ENSO Index (OEI) and is the first developed from atmospheric trace gas measurements. Using a data mining technique with existing ENSO indices of surface pressure and sea-surface temperature, the OEI is constructed by first averaging monthly mean column ozone over two broad regions in the western and eastern Pacific and taking their difference. This differencing yields a self-calibrating ENSO index which is independent of individual instrument calibration offsets and drifts in measurements over the long record. The combined Aura OMI and MLS ozone data confirm that zonal variability in total column ozone in the tropics caused by ENSO events lies almost entirely in the troposphere. As a result, the OEI can be derived directly from total column ozone instead of tropospheric column ozone. For clear-sky ozone measurements a +1 K change in Nino 3.4 index corresponds to +2.9 DU (Dobson Unit) change in the OEI, while a +1 hPa change in SOI coincides with a −1.7 DU change in the OEI. For ozone measurements under all cloud conditions these numbers are +2.4 DU and −1.4 DU, respectively. As an ENSO index based upon ozone, it is potentially useful in evaluating climate models predicting long term changes in ozone and other trace gases.

scholarly journals On ozone trend detection: using coupled chemistry-climate simulations to investigate early signs of total column ozone recovery

2017 ◽  
Author(s):  
James Keeble ◽  
Hannah Brown ◽  
N. Luke Abraham ◽  
Neil R. P. Harris ◽  
John A. Pyle
Keyword(s):  
Statistical Significance ◽  
Natural Variability ◽  
The Arctic ◽  
Early Recovery ◽  
Total Column Ozone ◽  
Column Ozone ◽  
The Tropics ◽  
The Impact ◽  
Total Column ◽  
Natural Cycles

Abstract. Total column ozone values from an ensemble of UM-UKCA model runs are examined to investigate different definitions of progress on the road to ozone recovery. This approach takes into account the internal atmospheric variability of the model in assessing the statistical significance of each definition. Three definitions of recovery are investigated: (i) a slowed rate of decline and the date of minimum column ozone; (ii) the identification of significant positive trends; and (iii) a return to historic values. A return to past thresholds is the last state to be achieved. However, while recovery may appear to be robust at a particular point of time, additional years of observations may lead to a reduced significance of trends due to natural variability (e.g. solar cycle, QBO, ENSO). This points to the need to ensure that the impact of natural cycles on total ozone is correctly described in statistical models, especially in the tropics where chemical depletion of the column is small. Trends for the 2000–2017 period are positive at most latitudes and are statistically significant when natural cycles are accounted for. This significance results largely from the large sample size of the multi-member ensemble. The influence of the natural cycles on trend determination is least at latitudes where the trends are sizeable. Thus, while ozone recovery can be identified in certain months over Antarctica, the mid-latitudes are the best place to identify early recovery as the trends are large compared to the variability. Over the Arctic, total column ozone is too variable for a signal to be easily detected: this arises both from the large dynamical interannual variability and from the large changes in chemical ozone loss from year to year. In the tropics, trends are too small compared to the natural variability to identify any statistical significance.

scholarly journals Estimates of Ozone Return Dates from Chemistry-Climate Model Initiative Simulations

2018 ◽  
Author(s):  
Sandip Dhomse ◽  
Douglas Kinnison ◽  
Martyn P. Chipperfield ◽  
Irene Cionni ◽  
Michaela Hegglin ◽  
...  
Keyword(s):  
Climate Model ◽  
Stratospheric Ozone ◽  
Tropospheric Chemistry ◽  
The Arctic ◽  
Polar Regions ◽  
Total Column Ozone ◽  
Column Ozone ◽  
The Tropics ◽  
The Impact ◽  
Total Column

Abstract. We analyse simulations performed for the Chemistry-Climate Model Initiative (CCMI) to estimate the return dates of the stratospheric ozone layer from depletion caused by anthropogenic stratospheric chlorine and bromine. We consider a total of 155 simulations from 20 models, including a range of sensitivity studies which examine the impact of climate change on ozone recovery. For the control simulations (unconstrained by nudging towards analysed meteorology) there is a large spread (±20 DU in the global average) in the predictions of the absolute ozone column. Therefore, the model results need to be adjusted for biases against historical data. Also, the interannual variability in the model results need to be smoothed in order to provide a reasonably narrow estimate of the range of ozone return dates. Consistent with previous studies, but here for a Representative Concentration Pathway (RCP) of 6.0, these new CCMI simulations project that global total column ozone will return to 1980 values in 2047 (with a 1-σ uncertainty of 2042–2052). At Southern Hemisphere mid-latitudes column ozone is projected to return to 1980 values in 2046 (2042–2050), and at Northern Hemisphere mid-latitudes in 2034 (2024–2044). In the polar regions, the return dates are 2062 (2055–2066) in the Antarctic in October and 2035 (2025–2040) in the Arctic in March. The earlier return dates in the NH reflect the larger sensitivity to dynamical changes. Our estimates of return dates are later than those presented in the 2014 Ozone Assessment by approximately 5–15 years, depending on the region. In the tropics only around half the models predict a return to 1980 values, at around 2040, while the other half do not reach this value. All models show a negative trend in tropical total column ozone towards the end of the 21st century. The CCMI models generally agree in their simulation of the time evolution of stratospheric chlorine, which is the main driver of ozone loss and recovery. However, there are a few outliers which show that the multi-model mean results for ozone recovery are not as tightly constrained as possible. Throughout the stratosphere the spread of ozone return dates to 1980 values between models tends to correlate with the spread of the return of inorganic chlorine to 1980 values. In the upper stratosphere, greenhouse gas-induced cooling speeds up the return by about 10–20 years. In the lower stratosphere, and for the column, there is a more direct link in the timing of the return dates, especially for the large Antarctic depletion. Comparisons of total column ozone between the models is affected by different predictions of the evolution of tropospheric ozone within the same scenario, presumably due to differing treatment of tropospheric chemistry. Therefore, for many scenarios, clear conclusions can only be drawn for stratospheric ozone columns rather than the total column. As noted by previous studies, the timing of ozone recovery is affected by the evolution of N2O and CH4. However, the effect in the simulations analysed here is small and at the limit of detectability from the few realisations available for these experiments compared to internal model variability. The large increase in N2O given in RCP 6.0 extends the ozone return globally by ~ 15 years relative to N2O fixed at 1960 abundances, mainly because it allows tropical column ozone to be depleted. The effect in extratropical latitudes is much smaller. The large increase in CH4 given in the RCP 8.5 scenario compared to RCP 6.0 also changes ozone return by ~ 15 years, again mainly through its impact in the tropics. For future assessments of single forcing or combined effects of CO2, CH4, and N2O on the stratospheric column ozone return dates, this work suggests that is more important to have multi-member (at least 3) ensembles for each scenario from each established participating model, rather than a large number of individual models.

Sign in / Sign up

Export Citation Format

Share Document