scholarly journals Direct-sun total ozone data from a Bentham spectroradiometer: methodology and comparison with satellite observations

2012 ◽  
Vol 5 (6) ◽  
pp. 8131-8160 ◽  
Author(s):  
M. Antón ◽  
R. Román ◽  
A. Valenzuela ◽  
F. J. Olmo ◽  
L. Alados-Arboledas
Keyword(s):  
Total Ozone ◽  
High Reliability ◽  
Surface Ozone ◽  
Lower Troposphere ◽  
Spectral Measurements ◽  
Retrieval Method ◽  
Stable Pattern ◽  
Differential Behavior ◽  
Relative Differences ◽  
Ozone Column

Abstract. A methodology to obtain the total ozone column (TOC) from the direct-solar spectral measurements of a Bentham spectroradiometer located at Granada (Spain) is presented in this paper. The method relies on the differential absorption technique using two pairs of direct irradiance at adjacent wavelengths between 305 and 340 nm. The extraterrestrial constant was determined from the extrapolation to zero air mass of each wavelength pair (Langley plot method). We checked the strong influence of the cloud cover on the Bentham TOC measurements using simultaneous sky images taken with an All-sky camera. Thus, reliable TOC data are exclusively obtained during cloud-free conditions or partly cloudy conditions without the solar disk obstructed. In this work, the hourly TOC averages retrieved by the Bentham instrument with a~standard deviation smaller than 3% (~ 10 Dobson Unit) are selected as high-quality TOC data. The analysis of the diurnal TOC variations during cloud-free days showed a differential behavior between the morning and afternoon periods. Thus, while the mornings exhibit an almost stable pattern, the afternoons displays a monotonic TOC increase which could be related to photochemical processes in the lower troposphere associated with the formation of surface ozone. Finally, the Bentham TOC measurements were validated against the satellite data derived from three satellite instruments: OMI, GOME and SCIAMACHY. The mean absolute values of the relative differences between satellite and ground-based data were smaller than 3% which highlight the high reliability of the retrieval method proposed in this paper to derive TOC data.

scholarly journals Direct-sun total ozone data from a spectroradiometer: methodology and comparison with satellite observations

2013 ◽  
Vol 6 (3) ◽  
pp. 637-647 ◽  
Author(s):  
M. Antón ◽  
R. Román ◽  
A. Valenzuela ◽  
F. J. Olmo ◽  
L. Alados-Arboledas
Keyword(s):  
Total Ozone ◽  
High Reliability ◽  
Surface Ozone ◽  
Lower Troposphere ◽  
Spectral Measurements ◽  
Retrieval Method ◽  
Stable Pattern ◽  
Relative Differences ◽  
Ozone Column ◽  
Absorption Technique

Abstract. A methodology to obtain the total ozone column (TOC) from the direct-sun spectral measurements of a Bentham spectroradiometer located at Granada (Spain) is presented in this paper. The method relies on the differential absorption technique using two pairs of direct irradiance at adjacent wavelengths between 305 and 340 nm. The extraterrestrial constant was determined from the extrapolation to zero air mass of each wavelength pair (Langley plot method). We checked the strong influence of the cloud cover on the Bentham TOC measurements using simultaneous sky images taken with an all-sky camera. Thus, reliable TOC data are exclusively obtained during cloud-free conditions or partly cloudy conditions without the solar disk obstructed. In this work, the hourly TOC averages retrieved by the Bentham instrument with a standard deviation smaller than 3% (~ 10 Dobson Unit) are selected as high-quality TOC data. The analysis of the diurnal TOC variations during cloud-free days in late spring and summer showed different TOC values between the morning and afternoon periods. Thus, while the mornings exhibit an almost stable pattern, the afternoons display a monotonic TOC increase which could be partially related to photochemical processes in the lower troposphere associated with the formation of surface ozone. Finally, the Bentham TOC measurements were compared against the satellite data derived from three satellite instruments: OMI, GOME and SCIAMACHY. The mean absolute values of the relative differences between satellite and ground-based data were smaller than 3%, highlighting the high reliability of the retrieval method proposed in this paper to derive TOC data.

scholarly journals Comparative Study of the Influence of Air Pollution on UVI at Maitri in Antarctica and New Delhi in India

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Nandita D. Ganguly
Keyword(s):  
Air Pollution ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Negative Correlation ◽  
Total Ozone ◽  
Surface Ozone ◽  
New Delhi ◽  
Increasing Trend ◽  
Ultraviolet Irradiance ◽  
Ozone Column

The influence of air pollution on the erythemal ultraviolet irradiance (UVI) reaching the earth's surface has been investigated at the Indian Antarctic station Maitri and compared with that at New Delhi, the capital of India, over a period of three years from 2005 to 2007. Total ozone column (TOC), surface ozone, NO2 column, middle tropospheric SO2 column, and BrO column are observed to exhibit a deceasing trend at Maitri, having a clean and pristine environment, while UVI and aerosol optical depth at 500 nm exhibit an increasing trend. This negative correlation suggests that O3, NO2, SO2, and BrO act as filters against erythemal ultraviolet irradiance reaching the earth's surface, while the aerosols, which are present in the atmosphere of Maitri, may not be either very effective in filtering out the UVI reaching the earth's surface or may not be large enough to produce measurable effects on UVI. TOC and BrO column are observed to exhibit a deceasing trend at New Delhi, having comparatively higher levels of pollution, while UVI, NO2 column, middle tropospheric SO2 column, surface ozone, and aerosol optical depth at 500 nm exhibit an increasing trend. This suggests that TOC and BrO act as filters against UVI, while NO2, surface ozone, SO2, and aerosols in the atmosphere of New Delhi may not be large enough to produce measurable effects on UVI.

scholarly journals TOC intercomparison of Brewer, Dobson and BTS Solar at Hohenpeißenberg and Davos 2019/2020

2021 ◽  
Author(s):  
Ralf Zuber ◽  
Ulf Köhler ◽  
Luca Egli ◽  
Mario Ribnitzky ◽  
Wolfgang Steinbrecht ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Total Ozone ◽  
Retrieval Algorithm ◽  
Spectral Measurements ◽  
Measurement Campaign ◽  
Stratospheric Temperature ◽  
Retrieval Algorithms ◽  
One Year ◽  
Double Monochromator ◽  
Ozone Column

Abstract. In the 2019/2020 measurement campaign at Hohenpeißenberg (Germany) and Davos (Switzerland) we compared the well-established Dobson and Brewer spectrometers (single and double monochromator Brewer) with newer BTS array spectroradiometer based systems in terms of total ozone column (TOC) determination. The aim of this study is to validate the BTS performance in a longer-term TOC analysis over more than one year with seasonal and weather influences. Two different BTS setups have been used. A fibre coupled entrance optic version by PMOD/WRC called Koherent and a diffusor optic which proved to be simpler in terms of calibration from Gigahertz-Optik GmbH called BTS Solar. The array-spectrometer based BTS systems have been traceable calibrated to National Metrology Institutes (NMI) and the used TOC retrieval algorithms are based on spectral measurements in the range of 305 nm and 350 nm instead of single wavelength measurements as for Brewer or Dobson. The two BTS based systems, however, used fundamentally different retrieval algorithms for the TOC assessment, whereby the retrieval of the BTS solar turned out to achieve significantly smaller seasonal drifts. The intercomparison showed a deviation of the BTS Solar to Brewers of < 0.1 % with an expanded standard deviation of < 1.5 % within the whole measurement campaign. Koherent showed a deviation of 1.7 % with an expanded standard deviation of 2.7 % mostly given by a significant seasonal drift. Resulting, the BTS Solar performance is comparable to Brewers at the comparison in Hohenpeißenberg. The slant path slope is in-between double monochromator and single monochromator Brewer. Koherent shows a strong seasonal variation in Davos due to the sensitivity of its ozone retrieval algorithm to stratospheric temperature similar to the Dobson results.

scholarly journals Evaluation of Total Ozone Column from Multiple Satellite Measurements in the Antarctic Using the Brewer Spectrophotometer

2021 ◽  
Vol 13 (8) ◽  
pp. 1594
Author(s):  
Songkang Kim ◽  
Sang-Jong Park ◽  
Hana Lee ◽  
Dha Hyun Ahn ◽  
Yeonjin Jung ◽  
...  
Keyword(s):  
Satellite Data ◽  
Total Ozone ◽  
Spatiotemporal Pattern ◽  
Satellite Measurements ◽  
Austral Spring ◽  
Total Ozone Column ◽  
Brewer Spectrophotometer ◽  
The Antarctic ◽  
Ozone Column

The ground-based ozone observation instrument, Brewer spectrophotometer (Brewer), was used to evaluate the quality of the total ozone column (TOC) produced by multiple polar-orbit satellite measurements at three stations in Antarctica (King Sejong, Jang Bogo, and Zhongshan stations). While all satellite TOCs showed high correlations with Brewer TOCs (R = ~0.8 to 0.9), there are some TOC differences among satellite data in austral spring, which is mainly attributed to the bias of Atmospheric Infrared Sounder (AIRS) TOC. The quality of satellite TOCs is consistent between Level 2 and 3 data, implying that “which satellite TOC is used” can induce larger uncertainty than “which spatial resolution is used” for the investigation of the Antarctic TOC pattern. Additionally, the quality of satellite TOC is regionally different (e.g., OMI TOC is a little higher at the King Sejong station, but lower at the Zhongshan station than the Brewer TOC). Thus, it seems necessary to consider the difference of multiple satellite data for better assessing the spatiotemporal pattern of Antarctic TOC.

Validation of gome total ozone column with the assimilation model KNMI

1998 ◽  
Vol 22 (11) ◽  
pp. 1501-1504
Author(s):  
A.J.M Piters ◽  
P.F Levelt ◽  
M.A.F Allaart ◽  
H.M Kelder
Keyword(s):  
Total Ozone ◽  
Total Ozone Column ◽  
Ozone Column ◽  
Assimilation Model

scholarly journals Comparison of GOME-2/MetOp total ozone data with Brewer spectroradiometer data over the Iberian Peninsula

2009 ◽  
Vol 27 (4) ◽  
pp. 1377-1386 ◽  
Author(s):  
M. Antón ◽  
D. Loyola ◽  
M. López ◽  
J. M. Vilaplana ◽  
M. Bañón ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Total Ozone ◽  
A Priori ◽  
Retrieval Algorithm ◽  
Data Dependencies ◽  
Ozone Data ◽  
Significant Dependence ◽  
Ozone Profile ◽  
Lower Variability ◽  
Relative Differences

Abstract. The main objective of this article is to compare the total ozone data from the new Global Ozone Monitoring Experiment instrument (GOME-2/MetOp) with reliable ground-based measurement recorded by five Brewer spectroradiometers in the Iberian Peninsula. In addition, a similar comparison for the predecessor instrument GOME/ERS-2 is described. The period of study is a whole year from May 2007 to April 2008. The results show that GOME-2/MetOp ozone data already has a very good quality, total ozone columns are on average 3.05% lower than Brewer measurements. This underestimation is higher than that obtained for GOME/ERS-2 (1.46%). However, the relative differences between GOME-2/MetOp and Brewer measurements show significantly lower variability than the differences between GOME/ERS-2 and Brewer data. Dependencies of these relative differences with respect to the satellite solar zenith angle (SZA), the satellite scan angle, the satellite cloud cover fraction (CF), and the ground-based total ozone measurements are analyzed. For both GOME instruments, differences show no significant dependence on SZA. However, GOME-2/MetOp data show a significant dependence on the satellite scan angle (+1.5%). In addition, GOME/ERS-2 differences present a clear dependence with respect to the CF and ground-based total ozone; such differences are minimized for GOME-2/MetOp. The comparison between the daily total ozone values provided by both GOME instruments shows that GOME-2/MetOp ozone data are on average 1.46% lower than GOME/ERS-2 data without any seasonal dependence. Finally, deviations of a priori climatological ozone profile used by the satellite retrieval algorithm from the true ozone profile are analyzed. Although excellent agreement between a priori climatological and measured partial ozone values is found for the middle and high stratosphere, relative differences greater than 15% are common for the troposphere and lower stratosphere.

scholarly journals On variability of total ozone derived from TOVS data over peninsular Indian sub-continent and adjoining oceanic area

MAUSAM ◽  
2022 ◽  
Vol 53 (4) ◽  
pp. 503-514
Author(s):  
R. SURESH
Keyword(s):  
Total Ozone ◽  
Monsoon Season ◽  
Lower Troposphere ◽  
Southwest Monsoon ◽  
Retrieval Algorithm ◽  
Tropospheric Temperature ◽  
Minimum Concentration ◽  
Upper Troposphere ◽  
Positive Correlation Coefficient ◽  
Longitudinal Variability

The total ozone derived from TOVS data from NOAA 12 satellite through one step physical retrieval algorithm of  International TOVS Processing Package (ITPP) version 5.0 has been used to identify  its diurnal, monthly, latitudinal and longitudinal variability during 1998 over the domain Equator to 26° N / 60-100° E. The linkage of  maximum total ozone with warmer tropopause and lower stratosphere has been re-established. The colder upper tropospheric temperature which is normally associated with maximum ozone concentration throughout the year elsewhere in the world  has also been identified in this study but the relationship gets reversed during southwest  monsoon months(June-September) over the domain considered. The moisture  available in abundance in the lower troposphere gets precipitated due to the convective instability prevailing in the atmosphere during monsoon season and very little moisture is only available for vertical transport into the upper troposphere atop 500 hPa. The latent heat released by the  precipitation processes warms up the middle and upper atmosphere. The warm and dry upper troposphere could be the reason for less depletion of ozone in the upper troposphere during monsoonal  months and this is supported by the positive correlation coefficient prevailing in monsoon season between  total ozone and upper tropospheric (aloft 300 hPa) temperature. The warmness in middle and upper troposphere which is associated with less depletion and/or production of more  ozone in the upper troposphere may  perhaps contribute  for the  higher total ozone during monsoon months than in other seasons over peninsular Indian region.  The minimum concentration is observed during January (226 DU) over 6° N and the maximum (283DU) over 18° N during August. Longitudinal variability is less pronounced than the latitudinal variability.

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