scholarly journals Study of SO2 and NO2 behaviour during the ozone-hole event at Antarctica by Brewer Spectrophotometer

MAUSAM ◽  
2021 ◽  
Vol 62 (4) ◽  
pp. 595-600
Author(s):  
S.K. PESHIN
Keyword(s):  
Sulphur Dioxide ◽  
Column Density ◽  
Ozone Hole ◽  
Vertical Column ◽  
Downward Shift ◽  
Maximum Value ◽  
Brewer Spectrophotometer ◽  
Vertical Column Density ◽  
Indian Station ◽  
Ozone Column

Vertical column density of sulphur dioxide has been measured at Maitri (70.7°S, 11.7°E), the Indian station in the Antarctica from September, 1999 to December, 2006 by a Brewer Spectrophotometer. Simultaneously, nitrogen dioxide, ozone and the maximum value of UV-B have also been measured, we found an increase in SO2 during spring. An increase in NO2 column was also found during this period but not identical with that of SO2. These variations in SO2 and NO2 are not in phase with the increase in UV-B flux at the ground due to the decrease of ozone column in the stratosphere. The variation of SO2 column is explained by the downward shift of penetration depth of UV-B radiation during the ozone-hole event.

Latitudinal variation of HNO3, HCl and HF vertical column density above 11.5 km

1982 ◽  
Vol 9 (2) ◽  
pp. 135-138 ◽  
Author(s):  
André Girard ◽  
Louis Gramont ◽  
Nicole Louisnard ◽  
Sylvie Le Boiteux ◽  
Gilbert Fergant
Keyword(s):  
Column Density ◽  
Latitudinal Variation ◽  
Vertical Column ◽  
Vertical Column Density

scholarly journals Intercomparison of Pandora Stratospheric NO<sub>2</sub> Slant Column Product with the NIWA M07 NDACC Standard

2017 ◽  
Author(s):  
Travis N. Knepp ◽  
Richard Querel ◽  
Paul Johnston ◽  
Larry Thomason ◽  
David Flittner ◽  
...  
Keyword(s):  
Column Density ◽  
Atmospheric Composition ◽  
Reference Spectrum ◽  
Vertical Column ◽  
Common Reference ◽  
Retrieval Algorithms ◽  
Vertical Column Density ◽  
Mass Factor ◽  
Validation Tool ◽  
Good Agreement

Abstract. In September 2014 a Pandora multi-spectral photometer operated by the SAGE-III project was sent to Lauder, New Zealand to operate side-by-side with the National Institute of Water and Atmospheric Research's (NIWA) Network for Detection of atmospheric Composition Change (NDACC) standard zenith slant column NO2 instrument to allow intercomparison between the two instruments, and evaluation of the Pandora unit as a potential SAGE-III validation tool for stratospheric NO2. This intercomparison spanned a full year, from September 2014–September 2015. Both datasets were produced using their respective native algorithms using a common reference spectrum (i.e. 12:00 on 26 February 2015). Throughout the entire deployment period both instruments operated in a zenith-only observation configuration. Though conversion from slant column density (SCD) to vertical-column density is routine (by application of an air mass factor), we limit the current analysis to SCD only. This omission is beneficial in that it provides a strict intercomparison of the two instruments and the retrieval algorithms as opposed to introducing an AMF-dependence in the intercomparison as well. It was observed that the current hardware configurations and retrieval algorithms are in good agreement (R > 0.95). The detailed results of this investigation are presented herein.

scholarly journals Version 2 Ozone Monitoring Instrument SO<sub>2</sub> Product (OMSO2 V2): New Anthropogenic SO<sub>2</sub> Vertical Column Density Dataset

2020 ◽  
Author(s):  
Can Li ◽  
Nickolay A. Krotkov ◽  
Peter J. T. Leonard ◽  
Simon Carn ◽  
Joanna Joiner ◽  
...  
Keyword(s):  
Column Density ◽  
A Priori ◽  
Principal Component ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Monitoring Instrument ◽  
Spectral Fitting ◽  
Vertical Column Density ◽  
Ozone Monitoring ◽  
So2 Pollution

Abstract. The Ozone Monitoring Instrument (OMI) has been providing global observations of SO2 pollution since 2004. Here we introduce the new anthropogenic SO2 vertical column density (VCD) dataset in the version 2 OMI SO2 product (OMSO2 V2). As with the previous version (OMSO2 V1.3), the new dataset is generated with an algorithm based on principal component analysis of OMI radiances, but features several updates. The most important among those is the use of expanded lookup tables and model a priori profiles to estimate SO2 Jacobians for individual OMI pixels, in order to better characterize pixel-to-pixel variations in SO2 sensitivity, including over snow and ice. Additionally, new data screening and spectral fitting schemes have been implemented to improve the quality of the spectral fit. As compared with the planetary boundary layer SO2 dataset in OMSO2 V1.3, the new dataset has substantially better data quality, especially over areas that are relatively clean or affected by the south Atlantic anomaly. The updated retrievals over snow/ice yield more realistic seasonal changes in SO2 at high latitudes and offer enhanced sensitivity to sources during wintertime. An error analysis has been conducted to assess uncertainties in SO2 VCDs from both the spectral fit and Jacobian calculations. The uncertainties from spectral fitting are reflected in SO2 slant column densities (SCDs) and largely depend on the signal-to-noise ratio of the measured radiances, as implied by the generally smaller SCD uncertainties over clouds or for lower solar zenith angles. The SCD uncertainties for individual pixels are estimated to be ~ 0.15–0.3 DU (Dobson Units) between ~ 40° S and ~ 40° N and to be ~ 0.2–0.5 DU at higher latitudes. The uncertainties from the Jacobians are approximately ~ 50–100 % over polluted areas, and primarily attributed to errors in SO2 a priori profiles and cloud pressures, as well as the lack of explicit treatment for aerosols. Finally, the daily mean and median SCDs over the presumably SO2-free equatorial East Pacific have increased by only ~ 0.0035 DU and ~ 0.003 DU respectively over the entire 15-year OMI record; while the standard deviation of SCDs has grown by only ~ 0.02 DU or ~ 10 %. Such remarkable long-term stability makes the new dataset particularly suitable for detecting regional changes in SO2 pollution.

scholarly journals Total columns of H<sub>2</sub>O measured from the ground and from space at Observatoire de Haute-Provence in France (44° N)

2013 ◽  
Vol 6 (3) ◽  
pp. 4249-4277
Author(s):  
S. Alkasm ◽  
A. Sarkissian ◽  
P. Keckhut ◽  
A. Pazmino ◽  
F. Goutail ◽  
...  
Keyword(s):  
Water Vapour ◽  
Column Density ◽  
Data Sets ◽  
Satellite Measurements ◽  
Vertical Column ◽  
Vertical Column Density ◽  
Satellite Sensors ◽  
Global Agreement ◽  
Density Of Water ◽  
Total Column

Abstract. In this work, we compare vertical column density of water vapour measured at Observatoire de Haute-Provence, Southern France (5° 42' E, +43° 55' N). Data were obtained by three satellite sensors, GOME, GOME 2 and SCIAMACHY, and by two ground-based spectrometers, Elodie and SAOZ. These five instruments are able to measure total column density of water vapour in the visible and have different principles of observation. All these instruments reproduce the total column water vapour with good accuracy. The mean difference between the satellite measurements, ground-based measurements, and between both types, are quantified. The diurnal cycle of water vapour above the station and its variability with latitude have been investigated. The differences between these data sets are due sometimes to the differences in the time of the measurements, or to the differences in the geometry of observations, or also due to both effects. The effect of land and sea and the effect of the season on the total column water vapour has been analysed. The global agreement between our data sets range from 10% in summer to 25% in winter, improved significantly when observations are closer in time and location.

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