scholarly journals Review of the article: Atmospheric Carbonyl Sulphide (OCS) measured remotely by FTIR solar absorption spectrometry by G. Toon et al.

2017 ◽  
Author(s):  
Anonymous
Keyword(s):  
Absorption Spectrometry ◽  
Solar Absorption ◽  
Carbonyl Sulphide

scholarly journals Atmospheric Carbonyl Sulphide (OCS) measured remotely by FTIR solar absorption spectrometry

2017 ◽  
Author(s):  
Geoffrey C. Toon ◽  
Jean-Francois L. Blavier ◽  
Keeyoon Sung
Keyword(s):  
Absorption Spectrometry ◽  
Early Summer ◽  
Solar Absorption ◽  
Spectral Fitting ◽  
The Past ◽  
Infra Red ◽  
Ftir Spectrometer ◽  
Carbonyl Sulphide ◽  
Balloon Measurements

Abstract. Atmospheric OCS abundances have been retrieved from spectra measured by the JPL MkIV Fourier Transform Infra-Red (FTIR) spectrometer during 24 balloon flights and during nearly 1100 days of ground-based observations since 1985. Our spectral fitting approach uses broad windows to enhance the precision and robustness of the retrievals. Since OCS has a vertical profile similar in shape to that of N2O, and since tropospheric N2O is very stable, we reference the OCS observations to those of N2O, measured simultaneously in the same airmass, to remove the effects of stratospheric transport, allowing a clearer assessment of secular changes in OCS. Balloon measurements reveal less than 5 % change in stratospheric OCS amounts over the past 25 years. In the troposphere a springtime peak of tropospheric OCS is seen, followed by a rapid early summer decrease, similar to the behavior of CO2. This results in a peak-to-peak seasonal cycle of 5–6 % of the total OCS column at Northern mid-latitudes. In the long-term tropospheric OCS record, a 5 % decrease is seen during 1990–2002, followed by a 5 % increase from 2003 to 2012.

scholarly journals Remote sensing of CO<sub>2</sub> and CH<sub>4</sub> using solar absorption spectrometry with a low resolution spectrometer

2012 ◽  
Vol 5 (7) ◽  
pp. 1627-1635 ◽  
Author(s):  
C. Petri ◽  
T. Warneke ◽  
N. Jones ◽  
T. Ridder ◽  
J. Messerschmidt ◽  
...  
Keyword(s):  
High Resolution ◽  
A Priori ◽  
Absorption Spectrometry ◽  
Total Carbon ◽  
High Spectral Resolution ◽  
Low Resolution ◽  
Average Deviation ◽  
Solar Absorption ◽  
Fourier Transform Spectrometry ◽  
The Difference

Abstract. Throughout the last few years solar absorption Fourier Transform Spectrometry (FTS) has been further developed to measure the total columns of CO2 and CH4. The observations are performed at high spectral resolution, typically at 0.02 cm−1. The precision currently achieved is generally better than 0.25%. However, these high resolution instruments are quite large and need a dedicated room or container for installation. We performed these observations using a smaller commercial interferometer at its maximum possible resolution of 0.11 cm−1. The measurements have been performed at Bremen and have been compared to observations using our high resolution instrument also situated at the same location. The high resolution instrument has been successfully operated as part of the Total Carbon Column Observing Network (TCCON). The precision of the low resolution instrument is 0.32% for XCO2 and 0.46% for XCH4. A comparison of the measurements of both instruments yields an average deviation in the retrieved daily means of &amp;leq;0.2% for CO2. For CH4 an average bias between the instruments of 0.47% was observed. For test cases, spectra recorded by the high resolution instrument have been truncated to the resolution of 0.11 cm−1. This study gives an offset of 0.03% for CO2 and 0.26% for CH4. These results indicate that for CH4 more than 50% of the difference between the instruments results from the resolution dependent retrieval. We tentatively assign the offset to an incorrect a-priori concentration profile or the effect of interfering gases, which may not be treated correctly.

scholarly journals Variations in the tropical uplift following the Pinatubo eruption studied by infrared solar absorption spectrometry

2000 ◽  
Vol 27 (17) ◽  
pp. 2609-2612 ◽  
Author(s):  
J. Notholt ◽  
G. C. Toon ◽  
B. Sen ◽  
N. B. Jones ◽  
C. P. Rinsland ◽  
...  
Keyword(s):  
Absorption Spectrometry ◽  
Solar Absorption ◽  
Pinatubo Eruption

scholarly journals Remote sensing of CO<sub>2</sub> and CH<sub>4</sub> using solar absorption spectrometry with a commercial low resolution spectrometer

2012 ◽  
Vol 5 (1) ◽  
pp. 245-269 ◽  
Author(s):  
C. Petri ◽  
T. Warneke ◽  
N. Jones ◽  
T. Ridder ◽  
J. Messerschmidt ◽  
...  
Keyword(s):  
High Resolution ◽  
A Priori ◽  
Absorption Spectrometry ◽  
Total Carbon ◽  
High Spectral Resolution ◽  
Low Resolution ◽  
Average Deviation ◽  
Solar Absorption ◽  
Fourier Transform Spectrometry ◽  
The Difference

Abstract. Throughout the last few years solar absorption Fourier Transform Spectrometry (FTS) has been further developed to measure the total columns of CO2 and CH4. The observations are performed at high spectral resolution, typically at 0.02 cm−1. The precision achieved is actually generally better than 0.25%. However, these high resolution instruments are quite large and need a dedicated room or container for installation. We performed these observations using a smaller commercial interferometer at its maximum possible resolution of 0.11 cm−1. The measurements have been performed at Bremen and have been compared to observations using our high resolution instrument also situated at the same location. The high resolution instrument has been successfully operated as part of the Total Carbon Column Observing Network (TCCON). The precision of the low resolution instrument is 0.32% for XCO2 and 0.46% for XCH4. A comparison of the measurements of both instruments yields an average deviation in the retrieved daily means of &amp;leq;0.2% for CO2. For CH4 an average bias between the instruments of 0.46% was observed. For test cases, spectra recorded by the high resolution instrument have been truncated to the resolution of 0.11 cm−1. This study gives an offset of 0.03% for CO2 and 0.26% for CH4. These results indicate that for CH4 more than 50% of the difference between the instruments results from the resolution dependant retrieval. We tentatively assign the offset to an incorrect a-priori concentration profile or the effect of interfering gases, which may not be treated correctly.

scholarly journals Pointing errors in solar absorption spectrometry – correction scheme and its validation

2015 ◽  
Vol 8 (6) ◽  
pp. 6179-6215
Author(s):  
A. Reichert ◽  
P. Hausmann ◽  
R. Sussmann
Keyword(s):  
Near Infrared ◽  
Rotation Axis ◽  
Solar Rotation ◽  
Absorption Spectrometry ◽  
Time Interval ◽  
A Posteriori ◽  
Vertical Column ◽  
Solar Absorption ◽  
Pointing Errors ◽  
Correction Scheme

Abstract. A method for quantification of sun-pointing inaccuracies in solar absorption spectrometry is presented along with a correction scheme for the resulting errors in trace gas vertical column or profile retrievals. A posteriori correction of pointing errors requires knowledge of both coordinates of the mispointing vector on the solar disk. In principle, quantitative information on the mispointing can be retrieved from Doppler shifts of solar lines derived from measured spectra. However, this yields only one component of the mispointing vector, namely the one which is perpendicular to the solar rotation axis. Missing information on the second vector component has hindered a posteriori correction of mispointing errors so far. Our idea to overcome this problem is to obtain estimates of both coordinates of the mispointing by combining subsequent measurements with differing orientations of the solar rotation axis relative to the zenith direction. An implementation of this original concept is demonstrated using measurements from the solar absorption Fourier transform infrared (FTIR) spectrometer at the Zugspitze (47.42° N, 10.98° E, 2964 m a.s.l.). Soundings in the September 2012 to September 2014 time interval were impacted by mispointing problems due to a non-optimum solar tracking optics configuration. They show a mean mispointing in zenith direction of −0.063°. This causes biases in vertical soundings of trace gases, e.g. −2.82 ppb in monthly means of dry-air column-averaged mole fractions of methane (XCH4). Measurements made with the more stable pre-September 2012 and post-September 2014 optics configurations show considerably smaller mispointing effects. Applying the mispointing correction, the April 2006–March 2014 XCH4 trend determined from Zugspitze measurements is reduced from 6.45 [5.84, 7.04] to 6.07 [5.55, 6.59] ppb yr−1. The correction thereby restores consistency with results from the nearby Garmisch FTIR site (47.48° N, 11.06° E, 743 m a.s.l.). The mispointing correction is applicable to solar absorption measurements in the mid infrared and near infrared. It will be of particular benefit for refining existing records of high-accuracy-and-precision greenhouse gas soundings for the purpose of improved trend analysis or source-sink inversions.

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.

Column densities of trace gases from FTIR solar absorption spectrometry at different spectral resolutions in the station Zugspitze

1995 ◽  
Author(s):  
Klaus Schaefer ◽  
Andreas Haak ◽  
Rainer Haus ◽  
Joerg Heland ◽  
Ralf Sussmann
Keyword(s):  
Trace Gases ◽  
Absorption Spectrometry ◽  
Solar Absorption
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