scholarly journals On the compatibility of Brewer total column ozone measurements in two adjacent valleys (Arosa and Davos) in the Swiss Alps

2017 ◽  
Vol 10 (11) ◽  
pp. 4479-4490 ◽  
Author(s):  
René Stübi ◽  
Herbert Schill ◽  
Jörg Klausen ◽  
Laurent Vuilleumier ◽  
Julian Gröbner ◽  
...  
Keyword(s):  
Time Series ◽  
Total Ozone ◽  
Stray Light ◽  
Swiss Alps ◽  
Total Column Ozone ◽  
Total Ozone Column ◽  
Set Up ◽  
Data Continuity ◽  
Ozone Column

Abstract. The Arosa site is well known in the ozone community for its continuous total ozone column observations that have been recorded since 1926. Originally based on Dobson sun spectrophotometers, the site has been gradually complemented by three automatic Brewer instruments, in operation since 1998. To secure the long-term ozone monitoring in this Alpine region and to benefit from synergies with the World Radiation Center, the feasibility of moving this activity to the nearby site at Davos (aerial distance of 13 km) has been explored. Concerns about a possible rupture of the 90-year-long record has motivated a careful comparison of the two sites, since great attention to the data continuity and quality has always been central to the operations of the observatory at Arosa. To this end, one element of the Arosa Brewer triad has been set up at the Davos site since November 2011 to realize a campaign of parallel measurements and to study the deviations between the three Brewer instruments. The analysis of the coincident measurement shows that the differences between Arosa and Davos remain within the range of the long-term stability of the Brewer instruments. A nonsignificant seasonal cycle is observed, which could possibly be induced by a stray-light bias and the altitude difference between the two sites. These differences are shown to be lower than the short-term variability of the time series and the overall uncertainty from individual Brewer instruments and therefore are not statistically significant. It is therefore concluded that the world's longest time series of the total ozone column obtained at Arosa site could be safely extended and continued with measurements taken from instruments located at the nearby Davos site without introducing a bias to this unique record.

scholarly journals On the compatibility of Brewer total column ozone measurements in two adjacent valleys (Arosa and Davos) in the Swiss Alps

2017 ◽  
Author(s):  
René Stübi ◽  
Herbert Schill ◽  
Jörg Klausen ◽  
Laurent Vuilleumier ◽  
Jülian Gröbner ◽  
...  
Keyword(s):  
Time Series ◽  
Total Ozone ◽  
Stray Light ◽  
Swiss Alps ◽  
Total Column Ozone ◽  
Total Ozone Column ◽  
Set Up ◽  
Data Continuity ◽  
Ozone Column

Abstract. The Arosa site is well known in the ozone community for its continuous total ozone column observations recorded since 1926. Originally based on Dobson sun spectrophotometers, the site has been gradually complemented by three automatic Brewer instruments, in operation since 1998. To secure the long term ozone monitoring in this Alpine region and to benefit from synergies with the World Radiation Center, the feasibility of moving this activity to the nearby site at Davos (aerial distance of 13 km) has 5 been explored. Concerns about a possible rupture of the 90 years long record has motivated a careful comparison of the two sites since great attention to the data continuity and quality has always been central to the operations of the observatory at Arosa. To this end, one element of the Arosa Brewer triad has been set up at the Davos site since November 2011 to realize a campaign of parallel measurements and to study the deviations between the three Brewer instruments. The analysis of the coincident measurements shows that the différences between Arosa and Davos remain within the range of the 10 long term stability of the Brewer instruments. A non-significant seasonal cycle is observed, which could possibly be induced by a stray light bias and the altitude difference between the two sites. These differences are shown to be lower than the short term variability of the time series and the overall uncertainty from individual Brewer instruments and therefore are not statistically significant. It is therefore concluded that the world’s longest time series of the total ozone column obtained at Arosa site could be safely extended and continued with measurements taken from instruments located at the nearby Davos site without 15 introducing a bias in this unique record.

scholarly journals Brewer spectrometer total ozone column measurements in Sodankylä

2016 ◽  
Vol 5 (1) ◽  
pp. 229-239 ◽  
Author(s):  
Tomi Karppinen ◽  
Kaisa Lakkala ◽  
Juha M. Karhu ◽  
Pauli Heikkinen ◽  
Rigel Kivi ◽  
...  
Keyword(s):  
Time Series ◽  
Total Ozone ◽  
Montreal Protocol ◽  
High Quality ◽  
Automatic Data ◽  
Mean Values ◽  
Total Ozone Column ◽  
Measurement Practices ◽  
Ozone Column

Abstract. Brewer total ozone column measurements started in Sodankylä in May 1988, 9 months after the signing of The Montreal Protocol. The Brewer instrument has been well maintained and frequently calibrated since then to produce a high-quality ozone time series now spanning more than 25 years. The data have now been uniformly reprocessed between 1988 and 2014. The quality of the data has been assured by automatic data rejection rules as well as by manual checking. Daily mean values calculated from the highest-quality direct sun measurements are available 77 % of time with up to 75 measurements per day on clear days. Zenith sky measurements fill another 14 % of the time series and winter months are sparsely covered by moon measurements. The time series provides information to survey the evolution of Arctic ozone layer and can be used as a reference point for assessing other total ozone column measurement practices.

scholarly journals Geophysical validation and long-term consistency between GOME-2/MetOp-A total ozone column and measurements from the sensors GOME/ERS-2, SCIAMACHY/ENVISAT and OMI/Aura

2012 ◽  
Vol 5 (9) ◽  
pp. 2169-2181 ◽  
Author(s):  
M. E. Koukouli ◽  
D. S. Balis ◽  
D. Loyola ◽  
P. Valks ◽  
W. Zimmer ◽  
...  
Keyword(s):  
Total Ozone ◽  
Satellite Monitoring ◽  
Total Ozone Column ◽  
Satellite Sensors ◽  
Data Processor ◽  
Ozone Monitoring ◽  
Scanning Imaging ◽  
Ozone Column ◽  
Seasonal Dependence

Abstract. The main aim of the paper is to assess the consistency of five years of Global Ozone Monitoring Experiment-2/Metop-A [GOME-2] total ozone columns and the long-term total ozone satellite monitoring database already in existence through an extensive inter-comparison and validation exercise using as reference Brewer and Dobson ground-based measurements. The behaviour of the GOME-2 measurements is being weighed against that of GOME (1995–2011), Ozone Monitoring Experiment [OMI] (since 2004) and the Scanning Imaging Absorption spectroMeter for Atmospheric CartograpHY [SCIAMACHY] (since 2002) total ozone column products. Over the background truth of the ground-based measurements, the total ozone columns are inter-evaluated using a suite of established validation techniques; the GOME-2 time series follow the same patterns as those observed by the other satellite sensors. In particular, on average, GOME-2 data underestimate GOME data by about 0.80%, and underestimate SCIAMACHY data by 0.37% with no seasonal dependence of the differences between GOME-2, GOME and SCIAMACHY. The latter is expected since the three datasets are based on similar DOAS algorithms. This underestimation of GOME-2 is within the uncertainty of the reference data used in the comparisons. Compared to the OMI sensor, on average GOME-2 data underestimate OMI_DOAS (collection 3) data by 1.28%, without any significant seasonal dependence of the differences between them. The lack of seasonality might be expected since both the GOME data processor [GDP] 4.4 and OMI_DOAS are DOAS-type algorithms and both consider the variability of the stratospheric temperatures in their retrievals. Compared to the OMI_TOMS (collection 3) data, no bias was found. We hence conclude that the GOME-2 total ozone columns are well suitable to continue the long-term global total ozone record with the accuracy needed for climate monitoring studies.

Temporal and Spatial Variability and Trend Investigation of Total Ozone Column over Iraq Employing Remote Sensing Data: 1979-2012

2015 ◽  
Vol 53 ◽  
pp. 1-18
Author(s):  
Ali M. Al-Salihi ◽  
Zehraa M. Hassan
Keyword(s):  
Remote Sensing ◽  
Spatial Variability ◽  
Total Ozone ◽  
Positive Trend ◽  
Climate Change Research ◽  
Total Ozone Column ◽  
Temporal And Spatial Variability ◽  
Temporal And Spatial ◽  
Ozone Column

The objective of this paper is to analyze the temporal and spatial variability of the total ozone column (TOC) distributions and trends over Iraq, during the last 30 years (1979–2012) using remote sensing-derived TOC data. Due to shortage of ground-based TOC measurements. TOC data derived from the Total Ozone Mapping Spectrometer (TOMS) for the period 1979–2004 and Ozone Monitoring Instrument (OMI) for the period 2005–2012 with spatial resolution (1o×1o) were used in present study. The spatial, long-term, monthly variations of TOC over Iraq were analysed. For the spatial variability, the latitudinal variability has a large range between (45 to 55) DU in winter and spring whereas during summer and autumn months ranged between (6 to 10) DU. Also represents an annual cycle with maximum in March and minimum in October. In contrast, the longitudinal variability is not significant. The long-term variability represented a notable decline for the period 1979–2012. The ozone negative trend was observed significantly during 1979–2004, for all months with trend ranged between (− 0.3 to 2) DU/year whereas the ozone positive trend was appear clearly during 2005–2007, for all months (0.1 to 2.3) DU/year ,except February and September which presented negative trends. The results can provide comprehensive descriptions of the TOC variations in Iraq and benefit climate change research in this region.

scholarly journals GUV long-term measurements of total ozone column and effective cloud transmittance at three Norwegian sites

2021 ◽  
Vol 21 (10) ◽  
pp. 7881-7899
Author(s):  
Tove M. Svendby ◽  
Bjørn Johnsen ◽  
Arve Kylling ◽  
Arne Dahlback ◽  
Germar H. Bernhard ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Total Ozone ◽  
Monitoring Network ◽  
High Time Resolution ◽  
Data Sets ◽  
Total Ozone Column ◽  
Ice Melt ◽  
Arctic Ice ◽  
Ozone Column

Abstract. Measurements of total ozone column and effective cloud transmittance have been performed since 1995 at the three Norwegian sites Oslo/Kjeller, Andøya/Tromsø, and in Ny-Ålesund (Svalbard). These sites are a subset of nine stations included in the Norwegian UV monitoring network, which uses ground-based ultraviolet (GUV) multi-filter instruments and is operated by the Norwegian Radiation and Nuclear Safety Authority (DSA) and the Norwegian Institute for Air Research (NILU). The network includes unique data sets of high-time-resolution measurements that can be used for a broad range of atmospheric and biological exposure studies. Comparison of the 25-year records of GUV (global sky) total ozone measurements with Brewer direct sun (DS) measurements shows that the GUV instruments provide valuable supplements to the more standardized ground-based instruments. The GUV instruments can fill in missing data and extend the measuring season at sites with reduced staff and/or characterized by harsh environmental conditions, such as Ny-Ålesund. Also, a harmonized GUV can easily be moved to more remote/unmanned locations and provide independent total ozone column data sets. The GUV instrument in Ny-Ålesund captured well the exceptionally large Arctic ozone depletion in March/April 2020, whereas the GUV instrument in Oslo recorded a mini ozone hole in December 2019 with total ozone values below 200 DU. For all the three Norwegian stations there is a slight increase in total ozone from 1995 until today. Measurements of GUV effective cloud transmittance in Ny-Ålesund indicate that there has been a significant change in albedo during the past 25 years, most likely resulting from increased temperatures and Arctic ice melt in the area surrounding Svalbard.

scholarly journals Adaption of an array spectroradiometer for total ozone column retrieval using direct solar irradiance measurements in the UV spectral range

2017 ◽  
Author(s):  
Ralf Zuber ◽  
Peter Sperfeld ◽  
Stefan Riechelmann ◽  
Saulius Nevas ◽  
Meelis Sildoja ◽  
...  
Keyword(s):  
Spectral Range ◽  
Solar Irradiance ◽  
Total Ozone ◽  
Spectral Irradiance ◽  
Stray Light ◽  
Limiting Factor ◽  
Total Ozone Column ◽  
Reduction Methods ◽  
Robust Measurements ◽  
Ozone Column

Abstract. A compact array spectroradiometer technology that enables precise and robust measurements of UV spectral irradiance is presented. The spectroradiometer design allows various applications such as measurement of high-power UV lamps, risk assessment of sources and measurement of solar irradiance. We show that this technology can perform precise total ozone column (TOC) retrieval. The internal stray light, which is often the limiting factor for measurements in the UV spectral range and increases the uncertainty for TOC analysis significantly, is physically reduced so that no other stray light 15 reduction methods, such as mathematical corrections, are necessary. The instrument and its elaborate components have been extensively characterised at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. During an international total ozone measurement intercomparison at the Izaña observatory in Tenerife, the high-quality applicability of the instrument was verified with measurements of the direct solar irradiance and subsequent TOC evaluations based on the spectral data between 12 and 30 September 2016. The results showed deviations of less than 1.5 % to most other instruments in most 20 situations not exceeding 3 % compared to established TOC measurement systems such as Dobson or Brewer.

scholarly journals Adaption of an array spectroradiometer for total ozone column retrieval using direct solar irradiance measurements in the UV spectral range

2018 ◽  
Vol 11 (4) ◽  
pp. 2477-2484 ◽  
Author(s):  
Ralf Zuber ◽  
Peter Sperfeld ◽  
Stefan Riechelmann ◽  
Saulius Nevas ◽  
Meelis Sildoja ◽  
...  
Keyword(s):  
Spectral Range ◽  
Solar Irradiance ◽  
Total Ozone ◽  
Stray Light ◽  
Limiting Factor ◽  
Light Reduction ◽  
Total Ozone Column ◽  
Reduction Methods ◽  
Robust Measurements ◽  
Ozone Column

Abstract. A compact array spectroradiometer that enables precise and robust measurements of solar UV spectral direct irradiance is presented. We show that this instrument can retrieve total ozone column (TOC) accurately. The internal stray light, which is often the limiting factor for measurements in the UV spectral range and increases the uncertainty for TOC analysis, is physically reduced so that no other stray-light reduction methods, such as mathematical corrections, are necessary. The instrument has been extensively characterised at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. During an international total ozone measurement intercomparison at the Izaña Atmospheric Observatory in Tenerife, the high-quality applicability of the instrument was verified with measurements of the direct solar irradiance and subsequent TOC evaluations based on the spectral data measured between 12 and 30 September 2016. The results showed deviations of the TOC of less than 1.5 % from most other instruments in most situations and not exceeding 3 % from established TOC measurement systems such as Dobson or Brewer.

scholarly journals Reconstruction and analysis of erythemal UV radiation time series from Hradec Králové (Czech Republic) over the past 50 years

2017 ◽  
Author(s):  
Klára Čížková ◽  
Kamil Láska ◽  
Ladislav Metelka ◽  
Martin Staněk
Keyword(s):  
Time Series ◽  
Czech Republic ◽  
Uv Radiation ◽  
Total Ozone ◽  
Cloud Cover ◽  
Radiation Doses ◽  
Total Ozone Column ◽  
Ozone Column ◽  
Radiation Time ◽  
Very High

Abstract. This paper evaluates the variability of erythemal ultraviolet (EUV) radiation from Hradec Králové (Czech Republic) in the period 1964–2013. The EUV radiation time series was reconstructed using a radiative transfer model and additional empirical relationships with the root mean square error of 9.9 %. The reconstructed time series documented the increase in EUV radiation doses in the 1980s and the 1990s (up to 15 % per decade), which is linked to the steep decline in total ozone (10 % per decade). The changes of cloud cover were the major factor affecting the EUV radiation doses especially in the 1960s, 1970s, and at the beginning of the new millennium. The mean annual EUV radiation doses in the decade 2004–2013 declined by 5 %. The factors affecting the EUV radiation doses differed also according to the chosen integration period (daily, monthly, and annually): solar zenith angle was the most important for daily doses, cloud cover for their monthly means, and the annual means of EUV radiation doses were most influenced by total ozone column. The number of days with very high EUV radiation doses increased by 22 % per decade, the increase was statistically significant in all seasons except autumn. The occurrence of the days with very high EUV doses was influenced mostly by low total ozone column (82 % of days), clear-sky or partly cloudy conditions (74 % of days) and by increased surface albedo (19 % of days). The principal component analysis documented that the occurrence of days with very high EUV radiation doses was much affected by the positive phase of North Atlantic Oscillation with an Azores High promontory reaching over central Europe. In the stratosphere, a strong Arctic circumpolar vortex and also the meridional inflow of ozone-poor air from the south-west were favorable for the occurrence of days with very high EUV radiation doses. This is the first analysis of the relationship between the high EUV radiation doses and macro-scale circulation patterns, and therefore more attention should be given also to other dynamical variables that may affect the solar UV radiation on the Earth surface.

scholarly journals Geophysical validation and long-term consistency between GOME-2/MetOp-A total ozone column and measurements from the sensors GOME/ERS-2, SCIAMACHY/ENVISAT and OMI/Aura

2012 ◽  
Vol 5 (2) ◽  
pp. 3019-3045
Author(s):  
M. E. Koukouli ◽  
D. S. Balis ◽  
D. Loyola ◽  
P. Valks ◽  
W. Zimmer ◽  
...  
Keyword(s):  
Total Ozone ◽  
Satellite Monitoring ◽  
Data Sets ◽  
Total Ozone Column ◽  
Satellite Sensors ◽  
Ozone Monitoring ◽  
Scanning Imaging ◽  
Ozone Column ◽  
Seasonal Dependence

Abstract. The main aim of the paper is to assess the consistency of five years of Global Ozone Monitoring Experiment-2/Metop-A (GOME-2) total ozone columns and the long-term total ozone satellite monitoring database already in existence through an extensive inter-comparison and validation exercise using as reference Brewer and Dobson ground-based measurements. The behaviour of the GOME-2 measurements is being weighed against that of GOME (1995–2011), Ozone Monitoring Experiment (OMI) (since 2004) and the Scanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) (since 2002) total ozone column products. Over the background truth of the ground-based measurements, the total ozone columns are inter-evaluated using a suite of established validation techniques; the GOME-2 time series follow the same patterns as those observed by the other satellite sensors and in particular, on the average, GOME-2 data underestimate GOME data by about 0.80%, and underestimate SCIAMACHY data by 0.37% with no seasonal dependence of the differences between GOME-2, GOME and SCIAMACHY. The latter is expected since the three data sets are based on similar DOAS algorithms. This underestimation of GOME-2 is within the uncertainty of the reference data used in the comparisons. Compared to the OMI sensor, on the average GOME-2 data underestimate OMI_DOAS (collection 3) data by 1.28%, without any significant seasonal dependence of the differences between them. The lack of seasonality might be expected since both GDP 4.4 and OMI_DOAS are DOAS-type algorithms and both consider the variability of the stratospheric temperatures in their retrievals. Compared to the OMI_TOMS (collection 3) data, no bias was found. We hence conclude that the GOME-2 total ozone columns are well suitable to continue the long-term global total ozone record with the accuracy needed for climate monitoring studies.

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