scholarly journals Pole-to-pole validation of GOME WFDOAS total ozone with groundbased data

2005 ◽  
Vol 5 (5) ◽  
pp. 1341-1355 ◽  
Author(s):  
M. Weber ◽  
L. N. Lamsal ◽  
M. Coldewey-Egbers ◽  
K. Bramstedt ◽  
J. P. Burrows
Keyword(s):  
Total Ozone ◽  
Weighting Function ◽  
Stratospheric Ozone ◽  
Extended Period ◽  
Companion Paper ◽  
Temperature Correction ◽  
Global Network ◽  
Optical Absorption Spectroscopy ◽  
Polar Regions ◽  
Data Processor

Abstract. This paper summarises the validation of GOME total ozone retrieved using the Weighting Function Differential Optical Absorption Spectroscopy (WFDOAS) algorithm Version 1.0. This algorithm has been described in detail in a companion paper by Coldewey-Egbers et al. (2005). Compared to the operational GDP (GOME Data Processor) V3, several improvements to the total ozone retrieval have been introduced that account for the varying ozone dependent contribution to rotational Raman scattering, includes a new cloud scheme, and uses the GOME measured effective albedo in the retrieval. In this paper the WFDOAS results have been compared with selected ground-based measurements from the WOUDC (World Ozone and UV Radiation Data Centre) that collects total ozone measurements from a global network of stations covering all seasons. From the global validation excellent agreement between WFDOAS and ground data was observed. The agreement lies within ±1%, and very little seasonal variations in the differences are found. In the polar regions and at high solar zenith angles, however, a positive bias varying between 5 and 8% is found near the polar night period. As a function of solar zenith angle as well as of the retrieved total ozone, the WFDOAS differences to ground polar data, however, show a much weaker dependence as compared to the operational GOME Data Processor Version 3 of GOME that represents a significant improvement. Very few stations carry out simultaneous measurements by Brewer and Dobson spectrometers over an extended period (three years or more). Simultaneous Brewer and Dobson measurements from Hradec Kralove, Czech Republic (50.2N, 15.8E) and Hohenpeissenberg, Germany (47.8N, 11.0E) covering the period 1996-1999 have been compared with our GOME results. Agreement with Brewers are generally better than with the simultaneous Dobson measurements and this may be explained by the neglect of stratospheric (ozone) temperature correction in the standard ozone retrieval from the ground.

scholarly journals Pole-to-pole validation of GOME WFDOAS total ozone with groundbased data

2004 ◽  
Vol 4 (5) ◽  
pp. 6909-6941 ◽  
Author(s):  
M. Weber ◽  
L. N. Lamsal ◽  
M. Coldewey-Egbers ◽  
K. Bramstedt ◽  
J. P. Burrows
Keyword(s):  
Total Ozone ◽  
Polar Region ◽  
Weighting Function ◽  
Stratospheric Ozone ◽  
Extended Period ◽  
Companion Paper ◽  
Temperature Correction ◽  
Global Network ◽  
Optical Absorption Spectroscopy ◽  
Better Than

Abstract. This paper summarises the validation of GOME total ozone retrieved using the weighting function differential optical absorption spectroscopy (WFDOAS) algorithm Version 1.0. This algorithm has been described in detail in a companion paper by Coldewey-Egbers et al. (2004). The WFDOAS results have been compared with selected ground-based measurements from the WOUDC (World Ozone and UV Radiation Data Centre) that collects total ozone measurements from a global network of stations covering all seasons. From the global validation excellent agreement between WFDOAS and ground data was found and on average agree to within ±1%. Very little seasonal variations in the observed differences are observed. In the polar region and at high solar zenith angles, however, a positive bias varying between 5 and 8% is found. Very few stations carry out simultaneous measurements by Brewer and Dobson spectrometers over an extended period (three years or more). Simultaneous Brewer and Dobson measurements from Hradec Kralove, Czech Republic (50.2° N, 15.8° E) and Hohenpeissenberg, Germany (47.8° N, 11.0° E) covering the period 1996–1999 have been compared with our GOME results. Agreement with Brewers are generally better than with the simultaneous Dobson measurements and this may be explained by the neglect of stratospheric (ozone) temperature correction in the standard ozone retrieval from the ground.

scholarly journals Total ozone retrieval from GOME UV spectral data using the weighting function DOAS approach

2005 ◽  
Vol 5 (4) ◽  
pp. 1015-1025 ◽  
Author(s):  
M. Coldewey-Egbers ◽  
M. Weber ◽  
L. N. Lamsal ◽  
R. de Beek ◽  
M. Buchwitz ◽  
...  
Keyword(s):  
Total Ozone ◽  
Weighting Function ◽  
Scattered Light ◽  
Companion Paper ◽  
Optical Absorption Spectroscopy ◽  
Wavelength Modulation ◽  
Vertical Column ◽  
Ozone Monitoring ◽  
First Time ◽  
Better Than

Abstract. A new algorithm approach called Weighting Function Differential Optical Absorption Spectroscopy (WFDOAS) is presented which has been developed to retrieve total ozone columns from nadir observations of the Global Ozone Monitoring Experiment. By fitting the vertically integrated ozone weighting function rather than ozone cross-section to the sun-normalized radiances, a direct retrieval of vertical column amounts is possible. The new WFDOAS approach takes into account the slant path wavelength modulation that is usually neglected in the standard DOAS approach using single airmass factors. This paper focuses on the algorithm description and error analysis, while in a companion paper by Weber et al. (2004) a detailed validation with groundbased measurements is presented. For the first time several auxiliary quantities directly derived from the GOME spectral range such as cloud-top-height and cloud fraction (O2-A band) and effective albedo using the Lambertian Equivalent Reflectivity (LER) near 377nm are used in combination as input to the ozone retrieval. In addition the varying ozone dependent contribution to the Raman correction in scattered light known as Ring effect has been included. The molecular ozone filling-in that is accounted for in the new algorithm has the largest contribution to the improved total ozone results from WFDOAS compared to the operational product. The precision of the total ozone retrieval is estimated to be better than 3% for solar zenith angles below 80°.

scholarly journals Total ozone column from Ozone Mapping and Profiler Suite Nadir Mapper (OMPS-NM) measurements using the broadband weighting function fitting approach (WFFA)

2021 ◽  
Vol 14 (8) ◽  
pp. 5771-5789
Author(s):  
Andrea Orfanoz-Cheuquelaf ◽  
Alexei Rozanov ◽  
Mark Weber ◽  
Carlo Arosio ◽  
Annette Ladstätter-Weißenmayer ◽  
...  
Keyword(s):  
Total Ozone ◽  
Weighting Function ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Polar Regions ◽  
Total Ozone Column ◽  
Function Fitting ◽  
Ozone Column ◽  
Good Agreement ◽  
Column Product

Abstract. A scientific total ozone column product from Ozone Mapping and Profiler Suite Nadir Mapper (OMPS-NM) observations and the retrieval algorithm are presented. The retrieval employs the weighting function fitting approach (WFFA), a modification of the weighting function differential optical absorption spectroscopy (WFDOAS) technique. The total ozone columns retrieved with WFFA are in very good agreement with other datasets. A mean difference of 0.3 % with respect to ground-based Brewer and Dobson measurements is observed. Seasonal and latitudinal variations are well represented and in agreement with other satellite datasets. The comparison of our product with the operational product of OMPS-NM indicates a mean bias of around zero. The comparison with the Tropospheric Monitoring Instrument products (S5P/TROPOMI) OFFL and WFDOAS shows a persistent negative bias of about −0.6 % for OFFL and −2.5 % for WFDOAS. Larger differences are only observed in the polar regions. This data product is intended to be used for trend analysis and the retrieval of tropospheric ozone combined with the OMPS limb profiler data.

scholarly journals Total ozone retrieval from GOME UV spectral data using the weighting function DOAS approach

2004 ◽  
Vol 4 (4) ◽  
pp. 4915-4944
Author(s):  
M. Coldewey-Egbers ◽  
M. Weber ◽  
L. N. Lamsal ◽  
R. de Beek ◽  
M. Buchwitz ◽  
...  
Keyword(s):  
Total Ozone ◽  
Weighting Function ◽  
Scattered Light ◽  
Companion Paper ◽  
Optical Absorption Spectroscopy ◽  
Wavelength Modulation ◽  
Vertical Column ◽  
First Time ◽  
Better Than ◽  
Ring Effect

Abstract. A new algorithm approach called Weighting Function Differential Optical Absorption Spectroscopy (WFDOAS) is presented which has been developed to retrieve total ozone columns from nadir observations of the Global Ozone Monitoring Experiment. By fitting the vertically integrated ozone weighting function rather than ozone cross-section to the sun-normalized radiances, a direct retrieval of vertical column amounts is possible. The new WFDOAS approach takes into account the slant path wavelength modulation that is usually neglected in the standard DOAS approach using single airmass factors. This paper focuses on the algorithm description and error analysis, while in a companion paper by Weber et al. (2004) a detailed validation with groundbased measurements is presented. For the first time several auxiliary quantities directly derived from the GOME spectral range such as cloud-top-height and cloud fraction (O2-A band) and effective albedo using the Lambertian Equivalent Reflectivity (LER) near 377 nm are used in combination as input to the ozone retrieval. In addition the varying ozone dependent contribution to the Raman correction in scattered light known as Ring effect has been included. Detailed investigations have been performed concerning the influence of the molecular ozone filling-in as part of the Ring effect. The precision of the total ozone retrieval is estimated to be better than 3% for solar zenith angles below 80°.

scholarly journals Global satellite validation of SCIAMACHY O<sub>3</sub> columns with GOME WFDOAS

2005 ◽  
Vol 5 (1) ◽  
pp. 795-813
Author(s):  
A. Bracher ◽  
M. Weber ◽  
K. Bramstedt ◽  
M. Coldewey-Egbers ◽  
L. N. Lamsal ◽  
...  
Keyword(s):  
Total Ozone ◽  
Weighting Function ◽  
Stratospheric Ozone ◽  
Data Retrieval ◽  
Imaging Spectrometer ◽  
Satellite Validation ◽  
Ozone Data ◽  
Data Processor ◽  
Global Coverage ◽  
Scanning Imaging

Abstract. Global stratospheric ozone columns measured by SCIAMACHY (Scanning Imaging Spectrometer for Atmospheric Chartography; data versions 5.01 and 5.04) aboard the recently launched Environmental Satellite (ENVISAT) from January to June 2003 were compared to collocated total ozone data from GOME (Global Ozone Monitoring Experiment on ERS-2) retrieved using the weighting function DOAS algorithm (WFDOAS; Version 1.0) in order to assess the level-2 data (trace gas data) retrieval accuracy from SCIAMACHY. The large number of collocated total ozone data from the two instruments which are flying in the same orbit were spatially binned into regular 2.5° and 2.5° grids and then compared. This binning method shows similar results than direct comparisons but is about thousand times faster. Results of these satellite comparisons show that SCIAMACHY O3 vertical columns (version 5.01/5.04) are on average 1% (±2%) lower than GOME WFDOAS and scatter increases at solar zenith angles above 85° and at low total ozone values. Results show dependencies on the seasonal cycle, latitudes, and total ozone amounts which are explained by the implementation of an old GOME algorithm based on GOME Data Processor (GDP) version 2.4 algorithm for the SCIAMACHY operational product. A reprocessing with an algorithm equivalent to GOME GDP version 4.0 and/or GOME WFDOAS V1.0 will improve significantly the quality of the SCIAMACHY ozone product. Since GOME lost its global coverage in July 2003 due to data rate limitation, continuation of the total ozone time series with SCIAMACHY is of highest importance for long-term trend monitoring.

scholarly journals Total ozone column retrieval from OMPS-NM measurements

2021 ◽  
Author(s):  
Andrea Orfanoz-Cheuquelaf ◽  
Alexei Rozanov ◽  
Mark Weber ◽  
Carlo Arosio ◽  
Annette Ladstätter-Weißenmayer ◽  
...  
Keyword(s):  
Total Ozone ◽  
Weighting Function ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Polar Regions ◽  
Total Ozone Column ◽  
Function Fitting ◽  
Ozone Column ◽  
Good Agreement ◽  
Column Product

Abstract. A scientific total ozone column product from the Ozone Mapping and Profiler Suite Nadir Mapper (OMPS-NM) observations and its retrieval algorithm are presented. The retrieval employs the Weighting Function Fitting Approach (WFFA), a modification of the Weighting Function Differential Optical Absorption Spectroscopy (WFDOAS) technique. The total ozone columns retrieved with WFFA are in very good agreement with other datasets. A mean difference of 0.6 % with respect to ground-based Brewer and Dobson measurements is observed. Seasonal and latitudinal variations are well represented and in agreement with other satellite datasets. The comparison of our product with the scientific product of OMPS-NM indicate a mean bias of around 0.1 %. The comparison with the Tropospheric Monitoring Instrument products (S5P/TROPOMI) OFFL and WFDOAS, shows a persistent negative bias of about −0.5 % for OFFL and –2 % for WFDOAS. Larger differences are only observed in the polar regions. This data product is intended to be used for trend analysis and the retrieval of tropospheric ozone combined with the OMPS limb profiler data.

scholarly journals Seasonal impact of biogenic VSL bromine on the evolution of mid-latitude lowermost stratospheric ozone during the 21<sup>st</sup> century

2020 ◽  
Author(s):  
Javer A. Barrera ◽  
Rafael P. Fernandez ◽  
Fernando Iglesias-Suarez ◽  
Carlos A. Cuevas ◽  
Jean-Francois Lamarque ◽  
...  
Keyword(s):  
21St Century ◽  
Total Ozone ◽  
Stratospheric Ozone ◽  
Polar Regions ◽  
Total Ozone Column ◽  
Seasonal Impact ◽  
The Tropics ◽  
The Impact ◽  
Ozone Column ◽  
Modelling Study

Abstract. Biogenic very short-lived bromine (VSLBr) represents, nowadays, ~ 25 % of the total stratospheric bromine loading. Owing to their much shorter lifetime compared to anthropogenic long-lived bromine (LLBr, e.g., halons) and chlorine (LLCl, e.g., chlorofluorocarbons) substances, the impact of VSLBr on ozone peaks at the extratropical lowermost stratosphere, a key climatic and radiative atmospheric region. Here we present a modelling study of the evolution of stratospheric ozone and its chemical losses in extra-polar regions during the 21st century, under two different scenarios: considering and neglecting the additional stratospheric injection of 5 ppt biogenic VSLBr naturally released from the ocean. Our analysis shows that the inclusion of VSLBr result in a realistic stratospheric bromine loading and improves the quantitative 1980–2015 model-satellite agreement of total ozone column (TOC) in the mid-latitudes. We show that the overall ozone response to VSLBr within the mid-latitudes follows the stratospheric abundances evolution of long-lived inorganic chlorine and bromine throughout the 21st century. Additional ozone losses due to VSLBr are maximised during the present-day period (1990–2010), with TOC differences of −8 DU (−3 %) and −5.5 DU (−2 %) for the southern (SH-ML) and northern (NH-ML) mid-latitudes, respectively. Moreover, the projected TOC differences at the end of the 21st century are at least half of the values found for the present-day period. In the tropics, a small (

scholarly journals Global satellite validation of SCIAMACHY O<sub>3</sub> columns with GOME WFDOAS

2005 ◽  
Vol 5 (9) ◽  
pp. 2357-2368 ◽  
Author(s):  
A. Bracher ◽  
L. N. Lamsal ◽  
M. Weber ◽  
K. Bramstedt ◽  
M. Coldewey-Egbers ◽  
...  
Keyword(s):  
Zenith Angle ◽  
Total Ozone ◽  
Solar Zenith Angle ◽  
Weighting Function ◽  
Stratospheric Ozone ◽  
Data Retrieval ◽  
Imaging Spectrometer ◽  
Ozone Data ◽  
Scanning Imaging

Abstract. Global stratospheric ozone columns derived from UV nadir spectra measured by SCIAMACHY (Scanning Imaging Spectrometer for Atmospheric Chartography; data ESA Versions 5.01 and 5.04) aboard the recently launched Environmental Satellite (ENVISAT) from January to June 2003 were compared to collocated total ozone data from GOME (Global Ozone Monitoring Experiment on ERS-2) retrieved using the weighting function DOAS algorithm (WFDOAS; Version 1.0) in order to assess the level-2 data (trace gas data) retrieval accuracy from SCIAMACHY. In addition, SCIAMACHY ozone columns retrieved with WFDOAS V1.0 were compared to GOME WFDOAS for some selected days in 2003 in order to separate data quality issues that either come from the optical performance of the instrument or algorithm implementation. Large numbers of collocated total ozone data from the two instruments, which are flying in the same orbit about 30 min apart, were spatially binned into regular 2.5° times 2.5° grids and then compared. Results of these satellite comparisons show that SCIAMACHY O3 vertical columns (ESA Version 5.01/5.04) are on average 1% (±2%) lower than GOME WFDOAS and scatter increases at solar zenith angles above 85° and at very low total ozone values. Results show dependencies on the solar zenith angle, latitudes, and total ozone amounts which are explained by the implementation of an outdated GOME algorithm based on GOME Data Processor (GDP) version 2.4 algorithms for the SCIAMACHY operational product. The reprocessing with an algorithm equivalent to GOME WFDOAS V1.0 shows that the offset and dependencies on solar zenith angle, latitude, and total ozone disappear and that SCIAMACHY WFDOAS data are within 1% of GOME WFDOAS. Since GOME lost its global coverage in July 2003 due to data rate limitation, continuation of the total ozone time series with SCIAMACHY is of highest importance for long-term trend monitoring. Since the beginning of its operation in March 2002 the SCIAMACHY instrument has performed stable. With the application of proper algorithms to retrieve total ozone, SCIAMACHY will be able to contribute to the global long term satellite total ozone record and it has the potential to achieve the high accuracy of GOME total ozone.

scholarly journals Comparison of total ozone from the satellite instruments GOME and TOMS with measurements from the Dobson network 1996–2000

2002 ◽  
Vol 2 (4) ◽  
pp. 1131-1157 ◽  
Author(s):  
K. Bramstedt ◽  
J. Gleason ◽  
D. Loyola ◽  
W. Thomas ◽  
A. Bracher ◽  
...  
Keyword(s):  
Total Ozone ◽  
Stratospheric Ozone ◽  
Network Data ◽  
Global Changes ◽  
Hemispheric Differences ◽  
Aging Effects ◽  
Data Processor ◽  
Ozone Column ◽  
Good Agreement

Abstract. Over the last 3 decades, satellite data have been used to monitor long-term global changes in stratospheric ozone. The TOMS series (1978 -- present) and GOME (1995 -- present) are two very important instruments in this context. In this paper, TOMS total ozone and three approaches to derive total ozone from GOME measurements are validated with ground-based Dobson network data. Beyond the operational products of both instruments, e.g. TOMS Version 7 and GOME Data Processor Version 2.7, total ozone is calculated by integrating FURM ozone profiles and by applying the TOMS algorithm to the GOME spectra. All algorithms show in general good agreement with ground-based measurements. The operational GOME total ozone shows seasonal variations, most likely introduced by difficulties in the derivation of airmass factors, which convert measured slant columns into vertical columns. The TOMS algorithm estimates on average 2% higher total ozone in the southern hemisphere than in the northern for both instruments as compared to the ground-based data, indicating that the source of the observed hemispheric differences is in the TOMS algorithm. Both instruments show aging effects in 2000, leading to enhanced variability in the ozone column differences with respect to Dobson data. In addition, the integrated GOME ozone profiles and the TOMS algorithm applied to GOME data show larger mean deviations in 2000.

scholarly journals Variability and trends in surface solar spectral ultraviolet irradiance in Italy: on the influence of geopotential height and lower-stratospheric ozone

2021 ◽  
Vol 21 (24) ◽  
pp. 18689-18705
Author(s):  
Ilias Fountoulakis ◽  
Henri Diémoz ◽  
Anna Maria Siani ◽  
Alcide di Sarra ◽  
Daniela Meloni ◽  
...  
Keyword(s):  
Geopotential Height ◽  
Total Ozone ◽  
Stratospheric Ozone ◽  
Extended Period ◽  
Spectral Irradiance ◽  
Positive Trend ◽  
Uv Irradiance ◽  
Ultraviolet Irradiance ◽  
Solar Uv Irradiance

Abstract. The short- and long-term variability of the surface spectral solar ultraviolet (UV) irradiance is investigated across Italy using high-quality ground-based measurements from three locations: Aosta (45.7∘ N, 7.4∘ E, 570 m a.s.l.), Rome (41.9∘ N, 12.5∘ E, 15 75 m a.s.l.), and Lampedusa (35.5∘ N, 12.6∘ E, 50 m a.s.l.). The three sites are characterized by different environmental conditions and represent almost the full latitudinal extent of the Italian territory. Data of two periods were analysed: 2006–2020 (all sites) and 1996–2020 (Rome only). The main objective of this study is to quantify the effect of the geopotential height (GPH) at 250 hPa on total ozone, and spectral irradiance at 307.5 and 324 nm. We first show that monthly anomalies in GPH, total ozone, and spectral irradiances are correlated amongst the three sites, suggesting that Italy is often affected by the same synoptical weather systems. We further find statistically significant anticorrelations between GPH and monthly anomalies in total ozone for all stations and months. Conversely, we identify positive correlations between GPH and monthly anomalies in spectral irradiance at 307.5 nm for most months. The influence of GPH on short-term variability also hold for long-term trends. For example, long-term changes in total ozone over the period 2006–2020 were associated with changes in GPH for all stations. This suggests that observed negative trends in total ozone were mainly driven by changes in lower-stratospheric ozone as upper-stratospheric ozone was increasing over this period. For several months of the year, positive trends in UV irradiance were observed, and we found that these trends were predominantly caused by changes in clouds and/or aerosols instead of total ozone. For the longer period of 1996–2020, a statistically significant annualized decrease in total ozone of ∼ 0.1 % per year was identified for Rome and could subsequently be attributed to decreasing lower-stratospheric ozone. While positive trends in spectral irradiance at 307.5 nm were observed for several months of this extended period, the negative trend in total ozone did not lead to a positive trend in the spectral irradiance at 307.5 nm in the deseasonalized data. Our study provides evidence that dynamical processes taking place in the troposphere lead to significant variability in total ozone and surface solar UV irradiance.

Sign in / Sign up

Export Citation Format

Share Document