scholarly journals A global ozone climatology from ozone soundings via trajectory mapping: a stratospheric perspective

2013 ◽  
Vol 13 (22) ◽  
pp. 11441-11464 ◽  
Author(s):  
J. Liu ◽  
D. W. Tarasick ◽  
V. E. Fioletov ◽  
C. McLinden ◽  
T. Zhao ◽  
...  
Keyword(s):  
Satellite Data ◽  
Lower Stratosphere ◽  
Stratospheric Ozone ◽  
A Priori ◽  
Forecast Model ◽  
Reanalysis Data ◽  
Trajectory Mapping ◽  
Decadal Variations ◽  
Mean Differences ◽  
The 1960S

Abstract. This study explores a domain-filling trajectory approach to generate a global ozone climatology from relatively sparse ozonesonde data. Global ozone soundings comprising 51 898 profiles at 116 stations over 44 yr (1965–2008) are used, from which forward and backward trajectories are calculated from meteorological reanalysis data to map ozone measurements to other locations and so fill in the spatial domain. The resulting global ozone climatology is archived monthly for five decades from the 1960s to the 2000s on a grid of 5° × 5° × 1 km (latitude, longitude, and altitude), from the surface to 26 km altitude. It is also archived yearly for the same period. The climatology is validated at 20 selected ozonesonde stations by comparing the actual ozone sounding profile with that derived through trajectory mapping of ozone sounding data from all stations except the one being compared. The two sets of profiles are in good agreement, both overall with correlation coefficient r = 0.991 and root mean square (RMS) of 224 ppbv and individually with r from 0.975 to 0.998 and RMS from 87 to 482 ppbv. The ozone climatology is also compared with two sets of satellite data from the Satellite Aerosol and Gas Experiment (SAGE) and the Optical Spectrography and InfraRed Imager System (OSIRIS). The ozone climatology compares well with SAGE and OSIRIS data in both seasonal and zonal means. The mean differences are generally quite small, with maximum differences of 20% above 15 km. The agreement is better in the Northern Hemisphere, where there are more ozonesonde stations, than in the Southern Hemisphere; it is also better in the middle and high latitudes than in the tropics where reanalysis winds are less accurate. This ozone climatology captures known features in the stratosphere as well as seasonal and decadal variations of these features. The climatology clearly shows the depletion of ozone from the 1970s to the mid 1990s and ozone increases in the 2000s in the lower stratosphere. When this climatology is used as the upper boundary condition in an Environment Canada operational chemical forecast model, the forecast is improved in the vicinity of the upper troposphere-lower stratosphere (UTLS) region. This ozone climatology is latitudinally, longitudinally, and vertically resolved and it offers more complete high latitude coverage as well as a much longer record than current satellite data. As the climatology depends on neither a priori data nor photochemical modeling, it provides independent information and insight that can supplement satellite data and model simulations of stratospheric ozone.

scholarly journals A global ozone climatology from ozone soundings via trajectory mapping: a stratospheric perspective

2013 ◽  
Vol 13 (6) ◽  
pp. 16831-16883
Author(s):  
J. Liu ◽  
D. W. Tarasick ◽  
V. E. Fioletov ◽  
C. McLinden ◽  
T. Zhao ◽  
...  
Keyword(s):  
Satellite Data ◽  
Lower Stratosphere ◽  
Stratospheric Ozone ◽  
A Priori ◽  
Correlation Coefficients ◽  
Forecast Model ◽  
Reanalysis Data ◽  
Trajectory Mapping ◽  
Decadal Variations ◽  
Mean Differences

Abstract. This study explores a domain-filling trajectory approach to generate a global ozone climatology from relatively sparse ozonesonde data. Global ozone soundings comprising 51 898 profiles at 116 stations over 44 yr (1965–2008) are used, from which forward and backward trajectories are calculated from meteorological reanalysis data, to map ozone measurements to other locations and so fill in the spatial domain. The resulting global ozone climatology is archived monthly for five decades from the 1960s to the 2000s on a~grid of 5° × 5° × 1 km (latitude, longitude, and altitude), from the surface to 26 km altitude. It is also archived yearly from 1965 to 2008. The climatology is validated at 20 selected ozonesonde stations by comparing the actual ozone sounding profile with that derived through trajectory mapping of ozone sounding data from all stations except the one being compared. The two sets of profiles are in good agreement, both individually with correlation coefficients (r) between 0.975 and 0.998 and root mean square (RMS) differences of 87 to 482 ppbv, and overall with r = 0.991 and an RMS of 224 ppbv. The ozone climatology is also compared with two sets of satellite data, from the Satellite Aerosol and Gas Experiment (SAGE) and the Optical Spectrography and InfraRed Imager System (OSIRIS). The ozone climatology compares well with SAGE and OSIRIS data in both seasonal and zonal means. The mean differences are generally quite small, with maximum differences of 20% above 15 km. The agreement is better in the Northern Hemisphere, where there are more ozonesonde stations, than in the Southern Hemisphere; it is also better in the middle and high latitudes than in the tropics where reanalysis winds are less accurate. This ozone climatology captures known features in the stratosphere, as well as seasonal and decadal variations of these features. Compared to current satellite data, it offers more complete high latitude coverage as well as a much longer record. The climatology shows clearly the depletion of ozone from the 1970s to the mid 1990s and ozone recovery in the lower stratosphere in the 2000s. When this climatology is used as the upper boundary condition in an Environment Canada operational chemical forecast model, the forecast is improved in the vicinity of the upper troposphere–lower stratosphere (UTLS) region. As this ozone climatology is neither dependent on a priori data nor photochemical modeling, it provides independent information and insight that can supplement satellite data and model simulations of stratospheric ozone.

scholarly journals Climatic variability of the mean flow and stationary planetary waves in the NCEP/NCAR reanalysis data

2008 ◽  
Vol 26 (5) ◽  
pp. 1233-1241 ◽  
Author(s):  
A. Yu. Kanukhina ◽  
E. V. Suvorova ◽  
L. A. Nechaeva ◽  
E. K. Skrygina ◽  
A. I. Pogoreltsev
Keyword(s):  
Lower Stratosphere ◽  
Climatic Variability ◽  
Reanalysis Data ◽  
Planetary Waves ◽  
Lower Atmosphere ◽  
Wave Number ◽  
Mean Flow ◽  
The Mean ◽  
The 1960S ◽  
Environmental Prediction

Abstract. NCEP/NCAR (National Center for Environmental Prediction – National Center for Atmospheric Research) data have been used to estimate the long-term variability of the mean flow, temperature, and Stationary Planetary Waves (SPW) in the troposphere and lower stratosphere. The results obtained show noticeable climatic variabilities in the intensity and position of the tropospheric jets that are caused by temperature changes in the lower atmosphere. As a result, we can expect that this variability of the mean flow will cause the changes in the SPW propagation conditions. The simulation of the SPW with zonal wave number m=1 (SPW1), performed with a linearized model using the mean flow distributions typical for the 1960s and for the beginning of 21st century, supports this assumption and shows that during the last 40 years the amplitude of the SPW1 in the stratosphere and mesosphere increased substantially. The analysis of the SPW amplitudes extracted from the geopotential height and zonal wind NCEP/NCAR data supports the results of simulation and shows that during the last years there exists an increase in the SPW1 activity in the lower stratosphere. These changes in the amplitudes are accompanied by increased interannual variability of the SPW1, as well. Analysis of the SPW2 activity shows that changes in its amplitude have a different sign in the northern winter hemisphere and at low latitudes in the southern summer hemisphere. The value of the SPW2 variability differs latitudinally and can be explained by nonlinear interference of the primary wave propagation from below and from secondary SPW2.

Temporal changes in the structure of the UTLS and their potential impact on lower stratospheric ozone

2020 ◽  
Author(s):  
Daniel Kunkel ◽  
Franziska Weyland ◽  
William Ball ◽  
Peter Hoor
Keyword(s):  
Lower Stratosphere ◽  
Stratospheric Ozone ◽  
Source Region ◽  
Reanalysis Data ◽  
Montreal Protocol ◽  
Successful Implementation ◽  
Internal Dynamic ◽  
Linear Modeling ◽  
Ozone Trends ◽  
Column Ozone

<p lang="en-US"><span>Although a general recovery of stratospheric ozone is expected after the successful implementation of the Montreal Protocol, strong indications for a decline in lower stratospheric ozone in the extratropics are still evident. Related studies attribute this decline to internal dynamic variability affecting the UTLS, in particular associated to the QBO and the exchange of air masses between tropical and extratropical regions. The dynamics affect the transport of ozone from the source region in the tropics into the extratropical lower stratosphere. More so, dynamics affect the structure of the lower stratosphere. In particular, the locations of the tropopause and of isentropic surfaces in the lower stratosphere, i.e., the region up to ~25 km altitude, affect the vertical profile of ozone and as such the integrated column ozone in the lower stratosphere. <br />This study aims to address the relation between the changing altitude of the tropopause and isentropic surfaces in the lower stratosphere and the declining ozone in the extratropical UTLS. For this we use reanalysis data from ECMWF and dynamic linear modeling to study trends of the dynamic tropopause and of the thermodynamical structure and the potential consequences of these trends for lower stratospheric ozone. In particular, we ask the question: do ozone trends still show a decline if we use a dynamic instead of a fixed coordinate system to calculate these trends?</span></p>

scholarly journals Ozone Profile Retrieval from nadir TROPOMI measurements in the UV range

2021 ◽  
Author(s):  
Nora Mettig ◽  
Mark Weber ◽  
Alexei Rozanov ◽  
Carlo Arosio ◽  
John P. Burrows ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Spectral Data ◽  
Stratospheric Ozone ◽  
A Priori ◽  
Mean Deviation ◽  
Vertical Resolution ◽  
Northern Latitudes ◽  
Ground Based Lidar ◽  
Using Data ◽  
Mean Differences

Abstract. The TOPAS algorithm to retrieve vertical profiles of ozone from space-borne observations in nadir viewing geometry has been developed at the Institute of Environmental Physics (IUP) of the University of Bremen and applied to TROPOMI L1B spectral data version 2. The spectral data between 270 and 329 nm are used for the retrieval. A re-calibration of the measured radiances is done using ozone profiles from MLS/Aura. Studies with synthetic spectra show that individual profiles in the stratosphere can be retrieved with the accuracy of about 10 %. In the troposphere, the retrieval errors are larger depending on the a-priori profile used. The vertical resolution above 18 km is about 6–10 km and it degrades to 15–25 km below. The vertical resolution in the troposphere is strongly dependent on the solar zenith angle (SZA). The ozone profiles retrieved from TROPOMI with the TOPAS algorithm were validated using data from ozone sondes and stratospheric ozone lidars. Above 18 km, the comparison with sondes shows excellent agreement within less than ±5 % for all latitudes. The standard deviation of mean differences is about 10 %. Below 18 km, the relative mean deviation in the tropics and northern latitudes is still quite good remaining within ±20 %. At southern latitudes larger differences of up to +40 % occur between 10 and 15 km. The standard deviation is about 50 % between 7–18 km and about 25 % below 7 km. The validation of stratospheric ozone profiles with ground-based lidar measurements also shows very good agreement. The relative mean deviation is below ±5 % between 18–45 km with a standard deviation of 10 %. TOPAS retrieval results for one day of TROPOMI observations were compared to MLS and OMPS-LP data. The relative mean difference was found to be largely below ±5 % between 20–50 km with exception of very high latitudes.

TOPAS ozone profile retrieval from TROPOMI L1B version 2 dataset

2021 ◽  
Author(s):  
Nora Mettig ◽  
Mark Weber ◽  
Alexei Rozanov ◽  
Carlo Arosio ◽  
John P. Burrows ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Stratospheric Ozone ◽  
A Priori ◽  
Spectral Radiance ◽  
Absolute Calibration ◽  
Mean Deviation ◽  
Data Set ◽  
Ozone Profile ◽  
Ground Based Lidar ◽  
Mean Differences

<p>The TOPAS (Tikhonov regularized Ozone Profile retrievAl with SCIATRAN) algorithm to retrieve vertical profiles of ozone from space-borne observations in nadir viewing geometry has been developed at the Institute of Environmental Physics (IUP) of the University of Bremen and applied to TROPOMI L1B spectral data version 2. The data set covers the period from June 2018 to October 2019. But it is not available continuously, but for only single weeks of all 3 months. TROPOMI spectral radiance from channel UV1 and UV2 between 270 nm and 331 nm are used for the retrieval. Since the ozone profiles are very sensitive to absolute calibration at short wavelengths, a re-calibration of the measured radiances is required using comparisons with simulated radiances with ozone limb profiles from collocated MLS/Aura used as input. The time-independent re-calibration bases on simulations for cloud-free pixels of four orbits distributed over the time period. Studies with synthetic spectra show that individual profiles in the stratosphere can be retrieved with the accuracy of about 10%. In the troposphere, the retrieval errors are larger depending on the a-priori profile used. The vertical resolution is between 6 and 10 km above 18 km altitude and 15 – 25 km below. There are around 6 degree of freedom between 0 – 60 km. The TOPAS ozone profiles retrieved from TROPOMI were validated using data from ozone sondes and stratospheric ozone lidars. Above 18 km, the comparison with sondes shows excellent agreement within less than ± 5% for all latitudes. The standard deviation of mean differences is about 10%. Below 18 km, the relative mean deviation in the tropics and northern latitudes is still quite good remaining within ± 20%. At southern latitudes larger differences of up to +40% occur between 10 and 15 km. Here the standard deviation is about 50% between 7 and 18 km and about 25% below 7 km. The validation of stratospheric ozone profiles with ground-based lidar measurements also shows very good agreement. The relative mean deviation is below ± 5% in the 18 – 45 km range with a standard deviation of 10%. A pilot application for one day of TROPOMI data with a comparison to MLS and OMPS confirmed the lidar validation results. The relative mean difference between TROPOMI and MLS or OMPS is largely below ± 5% between 20 – 50 km except for the very high latitudes where differences are getting larger.</p>

scholarly journals Ozone profile retrieval from nadir TROPOMI measurements in the UV range

2021 ◽  
Vol 14 (9) ◽  
pp. 6057-6082
Author(s):  
Nora Mettig ◽  
Mark Weber ◽  
Alexei Rozanov ◽  
Carlo Arosio ◽  
John P. Burrows ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Spectral Data ◽  
Stratospheric Ozone ◽  
A Priori ◽  
Mean Deviation ◽  
Vertical Resolution ◽  
Ozone Profile ◽  
Ground Based Lidar ◽  
Using Data ◽  
Mean Differences

Abstract. The TOPAS (Tikhonov regularised Ozone Profile retrievAl with SCIATRAN) algorithm to retrieve vertical profiles of ozone from space-borne observations in nadir-viewing geometry has been developed at the Institute of Environmental Physics (IUP) of the University of Bremen and applied to the TROPOspheric Monitoring Instrument (TROPOMI) L1B spectral data version 2. Spectral data between 270 and 329 nm are used for the retrieval. A recalibration of the measured radiances is done using ozone profiles from MLS/Aura. Studies with synthetic spectra show that individual profiles in the stratosphere can be retrieved with an uncertainty of about 10 %. In the troposphere, the retrieval errors are larger depending on the a priori profile used. The vertical resolution above 18 km is about 6–10 km, and it degrades to 15–25 km below. The vertical resolution in the troposphere is strongly dependent on the solar zenith angle (SZA). The ozone profiles retrieved from TROPOMI with the TOPAS algorithm were validated using data from ozonesondes and stratospheric ozone lidars. Above 18 km, the comparison with sondes shows excellent agreement within less than ±5 % for all latitudes. The standard deviation of mean differences is about 10 %. Below 18 km, the relative mean deviation in the tropics and northern latitudes is still quite good, remaining within ±20 %. At southern latitudes, larger differences of up to +40 % occur between 10 and 15 km. The standard deviation is about 50 % between 7–18 km and about 25 % below 7 km. The validation of stratospheric ozone profiles with ground-based lidar measurements also shows very good agreement. The relative mean deviation is below ±5 % between 18–45 km, with a standard deviation of 10 %. TOPAS retrieval results for 1 d of TROPOMI observations were compared to ozone profiles from the Microwave Limb Sounder (MLS) on the Aura satellite and the Ozone Mapping and Profiler Suite Limb Profiler (OMPS-LP). The relative mean difference was found to be largely below ±5 % between 20–50 km, except at very high latitudes.

Identifying periods of forecast model confidence for improved subseasonal prediction of precipitation in southern Australia

2020 ◽  
Author(s):  
Doug Richardson ◽  
James Risbey ◽  
Didier Monselesan
Keyword(s):  
A Priori ◽  
Forecast Model ◽  
Reanalysis Data ◽  
Lead Times ◽  
Conditional Distributions ◽  
Atmospheric Variability ◽  
Data Set ◽  
Typical Application ◽  
Model Skill ◽  
Circulation Patterns

<p>Subseasonal prediction skill of precipitation is typically low. Sometimes, however, forecasts are accurate and it would be useful to end-users to assess <em>a priori</em> if this might be the case. We use a 20-year hindcast data set of the ECMWF S2S prediction system and identify periods of high forecast confidence, evaluating model skill of precipitation forecasts for these periods compared to lower confidence predictions.</p><p>From reanalysis data, we derive a set of circulation patterns, called archetypes, that represent the broad-scale atmospheric circulation over Australia. These archetypes are combinations of ridges and troughs, and yield different precipitation patterns depending on the location of these features. In the literature, a typical application of circulation patterns is assigning daily reanalysis fields to the closest-matching pattern, thus obtaining conditional distributions of precipitation corresponding to key modes of atmospheric variability. A problem common to such analyses is that the precipitation distributions associated with the circulation patterns can be too similar; distinct distributions are required in order for the patterns to be useful in estimating precipitation. We show that by subsampling the archetype occurrences only when they are particularly well-matched to the underlying field, the conditional precipitation distributions become more distinct.</p><p>We subsample hindcast fields in the same way, obtaining a sample of periods when the model is confident about its prediction of the upcoming archetype. We then calculate model skill in predicting precipitation for three regions in southern Australia during such periods compared to when the model is not confident about the predicted archetype. Our results suggest that during periods of forecast confidence, precipitation skill is greater than normal for shorter leads (up to ten days) in two of the three regions (the Murray Basin and Western Tasmania). Skill for the third region (Southwest Western Australia) is greater during confident periods for lead times greater than one week, although this is marginal.</p>

scholarly journals Interannual Variability and Trends in Sea Surface Temperature, Lower and Middle Atmosphere Temperature at Different Latitudes for 1980–2019

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 454
Author(s):  
Andrew R. Jakovlev ◽  
Sergei P. Smyshlyaev ◽  
Vener Y. Galin
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Lower Stratosphere ◽  
Middle Atmosphere ◽  
Southern Oscillation ◽  
Lower Troposphere ◽  
Reanalysis Data ◽  
Sea Surface ◽  
The Arctic ◽  
The Impact

The influence of sea-surface temperature (SST) on the lower troposphere and lower stratosphere temperature in the tropical, middle, and polar latitudes is studied for 1980–2019 based on the MERRA2, ERA5, and Met Office reanalysis data, and numerical modeling with a chemistry-climate model (CCM) of the lower and middle atmosphere. The variability of SST is analyzed according to Met Office and ERA5 data, while the variability of atmospheric temperature is investigated according to MERRA2 and ERA5 data. Analysis of sea surface temperature trends based on reanalysis data revealed that a significant positive SST trend of about 0.1 degrees per decade is observed over the globe. In the middle latitudes of the Northern Hemisphere, the trend (about 0.2 degrees per decade) is 2 times higher than the global average, and 5 times higher than in the Southern Hemisphere (about 0.04 degrees per decade). At polar latitudes, opposite SST trends are observed in the Arctic (positive) and Antarctic (negative). The impact of the El Niño Southern Oscillation phenomenon on the temperature of the lower and middle atmosphere in the middle and polar latitudes of the Northern and Southern Hemispheres is discussed. To assess the relative influence of SST, CO2, and other greenhouse gases’ variability on the temperature of the lower troposphere and lower stratosphere, numerical calculations with a CCM were performed for several scenarios of accounting for the SST and carbon dioxide variability. The results of numerical experiments with a CCM demonstrated that the influence of SST prevails in the troposphere, while for the stratosphere, an increase in the CO2 content plays the most important role.

scholarly journals Evaluation of ozone profile and tropospheric ozone retrievals from GEMS and OMI spectra

2013 ◽  
Vol 6 (2) ◽  
pp. 239-249 ◽  
Author(s):  
J. Bak ◽  
J. H. Kim ◽  
X. Liu ◽  
K. Chance ◽  
J. Kim
Keyword(s):  
Spectral Resolution ◽  
Tropospheric Ozone ◽  
Stratospheric Ozone ◽  
A Priori ◽  
Ozone Monitoring Instrument ◽  
Satellite Platform ◽  
Ozone Profile ◽  
Retrieval Errors ◽  
Standard Deviations ◽  
Column Ozone

Abstract. South Korea is planning to launch the GEMS (Geostationary Environment Monitoring Spectrometer) instrument into the GeoKOMPSAT (Geostationary Korea Multi-Purpose SATellite) platform in 2018 to monitor tropospheric air pollutants on an hourly basis over East Asia. GEMS will measure backscattered UV radiances covering the 300–500 nm wavelength range with a spectral resolution of 0.6 nm. The main objective of this study is to evaluate ozone profiles and stratospheric column ozone amounts retrieved from simulated GEMS measurements. Ozone Monitoring Instrument (OMI) Level 1B radiances, which have the spectral range 270–500 nm at spectral resolution of 0.42–0.63 nm, are used to simulate the GEMS radiances. An optimal estimation-based ozone profile algorithm is used to retrieve ozone profiles from simulated GEMS radiances. Firstly, we compare the retrieval characteristics (including averaging kernels, degrees of freedom for signal, and retrieval error) derived from the 270–330 nm (OMI) and 300–330 nm (GEMS) wavelength ranges. This comparison shows that the effect of not using measurements below 300 nm on retrieval characteristics in the troposphere is insignificant. However, the stratospheric ozone information in terms of DFS decreases greatly from OMI to GEMS, by a factor of ∼2. The number of the independent pieces of information available from GEMS measurements is estimated to 3 on average in the stratosphere, with associated retrieval errors of ~1% in stratospheric column ozone. The difference between OMI and GEMS retrieval characteristics is apparent for retrieving ozone layers above ~20 km, with a reduction in the sensitivity and an increase in the retrieval errors for GEMS. We further investigate whether GEMS can resolve the stratospheric ozone variation observed from high vertical resolution Earth Observing System (EOS) Microwave Limb Sounder (MLS). The differences in stratospheric ozone profiles between GEMS and MLS are comparable to those between OMI and MLS below ~3 hPa (~40 km), except with slightly larger biases and larger standard deviations by up to 5%. At pressure altitudes above ~3 hPa, GEMS retrievals show strong influence of a priori and large differences with MLS, which, however, can be sufficiently improved by using better a priori information. The GEMS-MLS differences show negative biases of less than 4% for stratospheric column ozone, with standard deviations of 1–3%, while OMI retrievals show similar agreements with MLS except for 1% smaller biases at middle and high latitudes. Based on the comparisons, we conclude that GEMS will measure tropospheric ozone and stratospheric ozone columns with accuracy comparable to that of OMI and ozone profiles with slightly worse performance than that of OMI below ~3 hPa.

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