scholarly journals Quality assessment of ozone total column amounts as monitored by ground-based solar absorption spectrometry in the near infrared (> 3000 cm<sup>−1</sup>)

2014 ◽  
Vol 7 (9) ◽  
pp. 3071-3084 ◽  
Author(s):  
O. E. García ◽  
M. Schneider ◽  
F. Hase ◽  
T. Blumenstock ◽  
E. Sepúlveda ◽  
...  
Keyword(s):  
Spectral Region ◽  
Near Infrared ◽  
Systematic Difference ◽  
Total Carbon ◽  
Atmospheric Composition ◽  
High Spectral Resolution ◽  
Wave Number ◽  
Solar Absorption ◽  
Total Column

Abstract. This study examines the possibility of ground-based remote-sensing ozone total column amounts (OTC) from spectral signatures at 3040 and 4030 cm−1. These spectral regions are routinely measured by the NDACC (Network for the Detection of Atmospheric Composition Change) ground-based FTIR (Fourier transform infraRed) experiments. In addition, they are potentially detectable by the TCCON (Total Carbon Column Observing Network) FTIR instruments. The ozone retrieval strategy presented here estimates the OTC from NDACC FTIR high-resolution spectra with a theoretical precision of about 2 and 5% in the 3040 and 4030 cm−1 regions, respectively. Empirically, these OTC products are validated by inter-comparison to FTIR OTC reference retrievals in the 1000 cm−1 spectral region (standard reference for NDACC ozone products), using an 8-year FTIR time series (2005–2012) taken at the subtropical ozone supersite of the Izaña Atmospheric Observatory (Tenerife, Spain). Associated with the weaker ozone signatures at the higher wave number regions, the 3040 and 4030 cm−1 retrievals show lower vertical sensitivity than the 1000 cm−1 retrievals. Nevertheless, we observe that the rather consistent variations are detected: the variances of the 3040 cm−1 and the 4030 cm−1 retrievals agree within 90 and 75%, respectively, with the variance of the 1000 cm−1 standard retrieval. Furthermore, all three retrievals show very similar annual cycles. However, we observe a large systematic difference of about 7% between the OTC obtained at 1000 and 3040 cm−1, indicating a significant inconsistency between the spectroscopic ozone parameters (HITRAN, 2012) of both regions. Between the 1000 cm and the 4030 cm−1 retrieval the systematic difference is only 2–3%. Finally, the long-term stability of the OTC retrievals has also been examined, observing that both near-infrared retrievals can monitor the long-term OTC evolution, consistent with the 1000 cm−1 reference data. These findings demonstrate that recording the solar absorption spectra in the 3000 cm−1 spectral region at high spectral resolution (about 0.005 cm−1) might be useful for TCCON sites. Hence, both NDACC and TCCON ground-based FTIR experiments might contribute to global ozone databases.

scholarly journals Quality assessment of ozone total column amounts as monitored by ground-based solar absorption spectrometry in the near infrared (> 3000 cm<sup>−1</sup>)

2014 ◽  
Vol 7 (3) ◽  
pp. 2071-2106
Author(s):  
O. E. García ◽  
M. Schneider ◽  
F. Hase ◽  
T. Blumenstock ◽  
E. Sepúlveda ◽  
...  
Keyword(s):  
Near Infrared ◽  
Absorption Spectrometry ◽  
Systematic Difference ◽  
Total Carbon ◽  
Atmospheric Composition ◽  
Solar Absorption ◽  
Annual Cycles ◽  
Long Term Stability ◽  
Total Column

Abstract. This study examines the possibility of ground-based remote sensing ozone total column amounts (OTC) from spectral signatures at 3040 and 4030 cm−1. These spectral regions are routinely measured by the NDACC (Network for the Detection of Atmospheric Composition Change) ground-based FTIR (Fourier Transform InfraRed) experiments. In addition, they are potentially detectable by the TCCON (Total Carbon Column Observing Network) FTIR instruments. The ozone retrieval strategy presented here estimates the OTC from NDACC FTIR high resolution spectra with a theoretical precision of about 2% and 5% in the 3040 cm−1 and 4030 cm−1 regions, respectively. Empirically, these OTC products are validated by inter-comparison to FTIR OTC reference retrievals in the 1000 cm−1 spectral region (standard reference for NDACC ozone products), using a 8 year FTIR time series (2005–2012) taken at the subtropical ozone super-site of the Izaña Observatory (Tenerife, Spain). Associated with the weaker ozone signatures at the higher wavenumber regions, the 3040 cm−1 and 4030 cm−1 retrievals show lower vertical sensitivity than the 1000 cm−1 retrievals. Nevertheless, we observe that the rather consistent variations are detected: the variances of the 3040 cm−1 and the 4030 cm−1 retrievals agree within 90% and 75%, respectively, with the variance of the 1000 cm−1 standard retrieval. Furthermore, all three retrievals show very similar annual cycles. However, we observe a large systematic difference of about 7% between the OTC obtained at 1000 cm−1 and 3040 cm−1, indicating a significant inconsistency between the spectroscopic ozone parameters (HITRAN 2012) of both regions. Between the 1000 cm−1 and the 4030 cm−1 retrieval the systematic difference is only 2–3%. Finally, the long-term stability of the OTC retrievals has also been examined, observing that both near infrared retrievals can monitor the long-term OTC evolution in consistency to the 1000 cm−1reference data.

scholarly journals Retrieval of xCO<sub>2</sub> from ground-based mid-infrared (NDACC) solar absorption spectra and comparison to TCCON

2016 ◽  
Vol 9 (2) ◽  
pp. 577-585 ◽  
Author(s):  
Matthias Buschmann ◽  
Nicholas M. Deutscher ◽  
Vanessa Sherlock ◽  
Mathias Palm ◽  
Thorsten Warneke ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Seasonal Cycle ◽  
Total Carbon ◽  
Atmospheric Composition ◽  
Composition Change ◽  
Solar Absorption ◽  
Mid Infrared ◽  
Infrared Spectral ◽  
Ftir Spectrometer ◽  
Total Column

Abstract. High-resolution solar absorption spectra, taken within the Network for the Detection of Atmospheric Composition Change Infrared Working Group (NDACC-IRWG) in the mid-infrared spectral region, are used to infer partial or total column abundances of many gases. In this paper we present the retrieval of a column-averaged mole fraction of carbon dioxide from NDACC-IRWG spectra taken with a Fourier transform infrared (FTIR) spectrometer at the site in Ny-Ålesund, Spitsbergen. The retrieved time series is compared to colocated standard TCCON (Total Carbon Column Observing Network) measurements of column-averaged dry-air mole fractions of CO2 (denoted by xCO2). Comparing the NDACC and TCCON retrievals, we find that the sensitivity of the NDACC retrieval is lower in the troposphere (by a factor of 2) and higher in the stratosphere, compared to TCCON. Thus, the NDACC retrieval is less sensitive to tropospheric changes (e.g., the seasonal cycle) in the column average.

scholarly journals Remote sensing of water vapour profiles in the framework of the Total Carbon Column Observing Network (TCCON)

2010 ◽  
Vol 3 (4) ◽  
pp. 3987-4007
Author(s):  
M. Schneider ◽  
E. Sepúlveda ◽  
O. García ◽  
F. Hase ◽  
T. Blumenstock
Keyword(s):  
Water Vapour ◽  
Near Infrared ◽  
Total Carbon ◽  
Solar Absorption ◽  
Upper Troposphere ◽  
High Measurement ◽  
The Vertical Distribution

Abstract. We show that the near infrared solar absorption spectra recorded in the framework of the Total Carbon Column Observing Network (TCCON) can be used to derive the vertical distribution of tropospheric water vapour. Using spectral H2O signatures in the 4500–4700 cm−1 region one can well distinguish lower from middle/upper tropospheric water vapour concentrations. The vertical resolution is about 3 and 6 km, for the lower and middle/upper troposphere, respectively. We document the quality of the remotely-sensed profiles by comparisons with coincident in-situ Vaisala RS92 radiosonde measurements. The agreement of both techniques is very satisfactory. Due to the long-term strategy of the network and the high measurement frequency, the TCCON water vapour profile data offer novel opportunities for estimating the water vapour variability at different time scales and altitudes.

An 11 year record of GOSAT XCO2 measurements from NASA's ACOS version 9 retrieval algorithms: comparisons to models, TCCON, and OCO-2

2021 ◽  
Author(s):  
Thomas Taylor ◽  
Christopher O'Dell ◽  
Annmarie Eldering ◽  
David Crisp ◽  
Michael Gunson ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Total Carbon ◽  
High Spectral Resolution ◽  
Absorption Bands ◽  
Software Suite ◽  
Aggregated Data ◽  
Observation Network ◽  
Shortwave Infrared ◽  
Total Column

&lt;p&gt;The GOSAT TANSO-FTS sensor has been collecting high spectral resolution measurements of reflected solar radiation in the Oxygen A-band (0.76 microns) and two shortwave-infrared carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) absorption bands (1.6 and 2.0 microns) since April, 2009. The measured radiances allow for estimates of the total column carbon dioxide (XCO&lt;sub&gt;2&lt;/sub&gt;) via retrieval inversion. An eleven year long record of XCO&lt;sub&gt;2&amp;#160;&lt;/sub&gt;retrieved via NASA&amp;#8217;s Atmospheric Carbon Observations from Space (ACOS) build 9 software suite is analyzed and discussed. The v9 XCO&lt;sub&gt;2&amp;#160;&lt;/sub&gt;data has been publicly available on the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) since the spring of 2020.&lt;/p&gt;&lt;p&gt;The ACOS GOSAT v9 XCO&lt;sub&gt;2 &amp;#160;&lt;/sub&gt;is evaluated against CO&lt;sub&gt;2&amp;#160;&lt;/sub&gt;flux inversion models, observations from the Total Carbon Column Observation Network (TCCON), as well as against collocated measurements from NASA&amp;#8217;s OCO-2 satellite. The results indicate a product that agrees with OCO-2 and models within approximately 0.25 ppm with less than 1 ppm standard deviation (&amp;#963;). Agreement with TCCON is within approximately 0.1 ppm with approximately 1 ppm &amp;#963; for daily overpass mean aggregated data. The ACOS GOSAT v9 XCO&lt;sub&gt;2&amp;#160;&lt;/sub&gt;product will allow CO&lt;sub&gt;2&amp;#160;&lt;/sub&gt;flux inversion modelers and terrestrial ecologists to address questions about long term (decadal) carbon cycle dynamics related to net and gross carbon fluxes.&lt;/p&gt;

scholarly journals The arctic seasonal cycle of total column CO<sub>2</sub> and CH<sub>4</sub> from ground-based solar and lunar FTIR absorption spectrometry

2017 ◽  
Vol 10 (7) ◽  
pp. 2397-2411 ◽  
Author(s):  
Matthias Buschmann ◽  
Nicholas M. Deutscher ◽  
Mathias Palm ◽  
Thorsten Warneke ◽  
Christine Weinzierl ◽  
...  
Keyword(s):  
Seasonal Cycle ◽  
Model Comparison ◽  
Near Infrared ◽  
Absorption Spectrometry ◽  
Total Carbon ◽  
The Arctic ◽  
Solar Absorption ◽  
Novel Method ◽  
Total Column ◽  
Absorption Measurements

Abstract. Solar absorption spectroscopy in the near infrared has been performed in Ny-Ålesund (78.9° N, 11.9° E) since 2002; however, due to the high latitude of the site, the sun is below the horizon from October to March (polar night) and no solar absorption measurements are possible. Here we present a novel method of retrieving the total column dry-air mole fractions (DMFs) of CO2 and CH4 using moonlight in winter. Measurements have been taken during the polar nights from 2012 to 2016 and are validated with TCCON (Total Carbon Column Observing Network) measurements by solar and lunar absorption measurements on consecutive days and nights during spring and autumn. The complete seasonal cycle of the DMFs of CO2 and CH4 is presented and a precision of up to 0.5 % is achieved. A comparison of solar and lunar measurements on consecutive days during day and night in March 2013 yields non-significant biases of 0. 66 ± 4. 56 ppm for xCO2 and −1. 94 ± 20. 63 ppb for xCH4. Additionally a model comparison has been performed with data from various reanalysis models.

scholarly journals Profiling tropospheric CO<sub>2</sub> using the Aura TES and TCCON instruments

2012 ◽  
Vol 5 (3) ◽  
pp. 4495-4534 ◽  
Author(s):  
L. Kuai ◽  
J. Worden ◽  
S. Kulawik ◽  
K. Bowman ◽  
S. Biraud ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Near Infrared ◽  
Lower Troposphere ◽  
Total Carbon ◽  
Near Surface ◽  
Sources And Sinks ◽  
Global Carbon Budget ◽  
Regional Fluxes ◽  
Total Column

Abstract. Monitoring the global distribution and long-term variations of CO2 sources and sinks is required for characterizing the global carbon budget. Although total column measurements will be useful for estimating large regional fluxes, model transport error remains a significant error source, particularly for local sources and sinks. To improve the capability of estimating regional fluxes, we estimate near-surface CO2 values from ground-based near infrared (NIR) measurements with space-based thermal infrared (TIR) measurements. The NIR measurements are obtained from the Total Carbon Column Observing Network (TCCON) of solar measurements which provide an estimate of the total CO2 atmospheric column amount. Estimates of tropospheric CO2 that are co-located with TCCON are obtained by assimilating Tropospheric Emission Spectrometer (TES) free-tropospheric CO2 estimates into the GEOS-Chem model. Estimates of the boundary layer CO2 are obtained through simple subtraction, as the CO2 estimation problem is linear. We find that the calculated random uncertainties in total column and boundary layer estimates are consistent with actual uncertainties as compared to aircraft data. For the total column estimates the random uncertainty is about 0.55 ppm with a bias of −5.66 ppm, consistent with previously published results. After accounting for the total column bias, the bias in the boundary layer CO2 estimates is 0.26 ppm with a precision of 1.02 ppm This precision is sufficient for capturing the winter to summer variability of approximately 12 ppm in the lower troposphere; double the variability of the total column. This work shows that a combination of NIR and IR measurements can profile CO2 with the precisions and accuracy needed to quantify near-surface CO2 variability.

scholarly journals Source brightness fluctuation correction of solar absorption Fourier Transform mid infrared spectra

2011 ◽  
Vol 4 (1) ◽  
pp. 443-459
Author(s):  
T. Ridder ◽  
T. Warneke ◽  
J. Notholt
Keyword(s):  
Spectral Region ◽  
Near Infrared ◽  
Trace Gas ◽  
Solar Absorption ◽  
Mid Infrared ◽  
Infrared Spectral Region ◽  
Infrared Spectral ◽  
Brightness Fluctuation ◽  
Precision And Accuracy ◽  
Total Column

Abstract. Solar absorption Fourier Transform infrared spectrometry is considered a precise and accurate method for the observation of trace gases in the atmosphere. The precision and accuracy of such measurements are dependent on the stability of the light source. Fluctuations in the source brightness reduce the precision and accuracy of the trace gas concentrations, but cannot always be avoided. Thus, a strong effort is made within the community to reduce the impact of source brightness fluctuations by applying a correction on the spectra following the measurements. So far, it could be shown that the precision and accuracy of CO2 total column concentrations could be improved by applying a source brightness fluctuation correction to spectra in the near infrared spectral region. The analysis of trace gas concentrations obtained from spectra in the mid infrared spectral region is fundamental. However, spectra below 2000 cm−1 are generally considered uncorrectable, if they are measured with a MCT detector. Such measurements introduce an unknown offset to MCT interferograms, which prevents a source brightness fluctuation correction. Here, we show a method of source brightness fluctuation correction, which can be applied on spectra in the whole infrared spectral region including spectra measured with a MCT detector. We present a solution to remove the unknown offset in MCT interferograms allowing MCT spectra for an application of source brightness fluctuation correction. This gives an improvement in the quality of MCT spectra and we demonstrate an improvement in the retrieval of O3 profiles and total column concentrations. For a comparison with previous studies, we apply our source brightness fluctuation correction method on spectra in the near infrared spectral region and show an improvement in the retrieval of CO2 total column concentrations.

scholarly journals Profiling tropospheric CO<sub>2</sub> using Aura TES and TCCON instruments

2013 ◽  
Vol 6 (1) ◽  
pp. 63-79 ◽  
Author(s):  
L. Kuai ◽  
J. Worden ◽  
S. Kulawik ◽  
K. Bowman ◽  
M. Lee ◽  
...  
Keyword(s):  
Near Infrared ◽  
Regional Scale ◽  
Lower Troposphere ◽  
Total Carbon ◽  
Sources And Sinks ◽  
Global Carbon Budget ◽  
Random Uncertainties ◽  
Global Carbon ◽  
Total Column

Abstract. Monitoring the global distribution and long-term variations of CO2 sources and sinks is required for characterizing the global carbon budget. Total column measurements are useful for estimating regional-scale fluxes; however, model transport remains a significant error source, particularly for quantifying local sources and sinks. To improve the capability of estimating regional fluxes, we estimate lower tropospheric CO2 concentrations from ground-based near-infrared (NIR) measurements with space-based thermal infrared (TIR) measurements. The NIR measurements are obtained from the Total Carbon Column Observing Network (TCCON) of solar measurements, which provide an estimate of the total CO2 column amount. Estimates of tropospheric CO2 that are co-located with TCCON are obtained by assimilating Tropospheric Emission Spectrometer (TES) free tropospheric CO2 estimates into the GEOS-Chem model. We find that quantifying lower tropospheric CO2 by subtracting free tropospheric CO2 estimates from total column estimates is a linear problem, because the calculated random uncertainties in total column and lower tropospheric estimates are consistent with actual uncertainties as compared to aircraft data. For the total column estimates, the random uncertainty is about 0.55 ppm with a bias of −5.66 ppm, consistent with previously published results. After accounting for the total column bias, the bias in the lower tropospheric CO2 estimates is 0.26 ppm with a precision (one standard deviation) of 1.02 ppm. This precision is sufficient for capturing the winter to summer variability of approximately 12 ppm in the lower troposphere; double the variability of the total column. This work shows that a combination of NIR and TIR measurements can profile CO2 with the precision and accuracy needed to quantify lower tropospheric CO2 variability.

Semiautonomous FTS Observation System for Remote Sensing of Stratospheric and Tropospheric Gases

2009 ◽  
Vol 26 (9) ◽  
pp. 1814-1828 ◽  
Author(s):  
James W. Hannigan ◽  
Michael T. Coffey ◽  
Aaron Goldman
Keyword(s):  
Estimation Method ◽  
Optimal Estimation ◽  
Atmospheric Composition ◽  
Observation System ◽  
Spectra Analysis ◽  
Solar Absorption ◽  
Analysis Methodology ◽  
And Control ◽  
Total Column

Abstract A solar-viewing Fourier transform spectrometer (FTS) at Thule, Greenland (76.5°N, 68.8°W, 225 m MSL), has been in operation as part of the Network for the Detection of Atmospheric Composition Change [NDACC; formerly the Network for the Detection of Stratospheric Change (NDSC)] since 1999. Observations have been made, on average, 77 days yr−1 during the 8 months, excluding polar night. The semiautonomous operation of the instrument, including its associated optical, cryogenic, and control systems, is of primary importance to acquiring long-term data records efficiently and is herein described. Discussed in this paper are the data processing and spectra analysis methodology that are used to convert the measured interferograms into geophysical data products. Vertical profile retrievals derived from the high-resolution solar absorption spectra use the optimal estimation method. Total column amounts then represent the integration of these vertical profiles. As an example of this process, results are presented for daily average total column amounts of HF, HCl, ClONO2, and CCl2F2 from 2001 through 2007. The means of unperturbed summertime observations are used in a preliminary study of their annual trends.

scholarly journals The arctic seasonal cycle of total column CO<sub>2</sub> and CH<sub>4</sub> from ground-based solar and lunar FTIR absorption spectrometry

2017 ◽  
Author(s):  
Matthias Buschmann ◽  
Nicholas M. Deutscher ◽  
Mathias Palm ◽  
Thorsten Warneke ◽  
Christine Weinzierl ◽  
...  
Keyword(s):  
Seasonal Cycle ◽  
Model Comparison ◽  
Near Infrared ◽  
Absorption Spectrometry ◽  
Total Carbon ◽  
The Arctic ◽  
Solar Absorption ◽  
Novel Method ◽  
Total Column ◽  
Absorption Measurements

Abstract. Solar absorption spectroscopy in the near infrared has been performed in Ny-Ålesund (78.9° N, 11.9° E) since 2002; however, due to the high latitude of the site, the sun is below the horizon from October to March (Polar Night) and no solar absorption measurements are possible. Here we present a novel method of retrieving the total column dry-air mole fractions (DMF) of CO2 and CH4 using the moon as a light source in winter. Measurements have been taken during the Polar Nights from 2012 to 2016 and are validated with TCCON (Total Carbon Column Observing Network) measurements by parallel solar and lunar absorption measurements during spring and autumn. The complete seasonal cycle of the DMFs of CO2 and CH4 is presented and a precision of up to 0.5 % is achieved. Additionally a model comparison has been performed with data from various reanalysis models.

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