Carbon monoxide measurements onboard the CARIBIC passenger aircraft using UV resonance fluorescence

Scharffe, D.; Šlemr, F.; Brenninkmeijer, Carl A. M.; Zahn, Andreas

doi:10.5194/amt-5-1753-2012

Cited by 43 publications

(31 citation statements)

References 27 publications

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“…Figure 6b (third panel) repeats the latitudinal profile of CH 4 between 30°S and 30°N, but here showing values only for December 2010. The highest values are measured around the equator, where also carbon monoxide (CO) mixing ratios, measured in‐flight with an ultraviolet fluorescence instrument at a time resolution of 1 s [ Scharffe et al , 2012], are elevated. For individual months, the position of the maximum follows the latitudinal shift in upper tropospheric wind patterns, related to the location of the ITCZ and the meandering of the westerly jet.…”

Section: Resultsmentioning

confidence: 99%

Distribution of methane in the tropical upper troposphere measured by CARIBIC and CONTRAIL aircraft

Schuck¹,

Ishijima²,

Patra³

et al. 2012

J. Geophys. Res.

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[1] We investigate the upper tropospheric distribution of methane (CH 4 ) at low latitudes based on the analysis of air samples collected from aboard passenger aircraft. The distribution of CH 4 exhibits spatial and seasonal differences, such as the pronounced seasonal cycles over tropical Asia and elevated mixing ratios over central Africa. Over Africa, the correlations of methane, ethane, and acetylene with carbon monoxide indicate that these high mixing ratios originate from biomass burning as well as from biogenic sources. Upper tropospheric mixing ratios of CH 4 were modeled using a chemistry transport model. The simulation captures the large-scale features of the distributions along different flight routes, but discrepancies occur in some regions. Over Africa, where emissions are not well constrained, the model predicts a too steep interhemispheric gradient. During summer, efficient convective vertical transport and enhanced emissions give rise to a large-scale CH 4 maximum in the upper troposphere over subtropical Asia. This seasonal (monsoonal) cycle is analyzed with a tagged tracer simulation. The model confirms that in this region convection links upper tropospheric mixing ratios to regional sources on the Indian subcontinent, subtropical East Asia, and Southeast Asia. This type of aircraft data can therefore provide information about surface fluxes.

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Section: Resultsmentioning

confidence: 99%

Distribution of methane in the tropical upper troposphere measured by CARIBIC and CONTRAIL aircraft

Schuck¹,

Ishijima²,

Patra³

et al. 2012

J. Geophys. Res.

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“…Routine deployment of the current system started in May 2005 and is ongoing. The instrumentation includes an in situ analyser for continuous measurements of CO based on a commercial ultraviolet fluorescence instrument (Aero-Laser, AL 5002) which has been modified for use onboard aircraft (Scharffe et al, 2012). The instrument achieves a precision of 1-2 ppbv, the time resolution is 1 s. Calibration is in-flight every 25 min.…”

Section: Caribicmentioning

confidence: 99%

“…AIRS and IASI CO retrievals are compared to CARIBIC CO measurements (Brenninkmeijer et al, 2007;Scharffe et al, 2012). While analysing the results of this comparison, one has to keep in mind that CARIBIC measures CO at a given altitude in the range 9-12 km, whereas an integrated content of tropospheric CO is retrieved from AIRS and IASI (see December 2010, which are transition months between the fire seasons in the Southern Hemisphere (SH) and in the Northern Hemisphere (NH).…”

Section: Comparison With Caribicmentioning

confidence: 99%

Retrieval of tropospheric CO column from hyperspectral infrared sounders – application to four years of Aqua/AIRS and MetOp-A/IASI

et al. 2012

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Abstract. Four years of tropospheric integrated content of CO were retrieved from infrared hyperspectral observations of AIRS onboard Aqua and IASI onboard MetOp-A, for the period July 2007-June 2011. The retrieval method is based on a double differential approach that relies on the difference between brightness temperatures observed by the sounder and BT simulated by the Automatised Atmospheric Absorption Atlas (4A) radiative transfer model on colocated ECMWF reanalyses, for several couples of channels located in the 4.67 µm CO band. AIRS and IASI give access to similar integrated contents of CO with a maximum sensitivity near 450 hPa and a half-height width of the weighting function between 200 and 750 hPa depending on the thermal contrast (i.e., the difference between the surface temperature and the temperature of the first pressure level). However, differences in their spectral and radiometric characteristics yield differences in the retrieval characteristics with AIRS selected couples of channels being more sensitive to surface characteristics. Moreover, IASI covers the whole CO absorption band, with a 3 times better spectral resolution, giving access to channels presenting a 3 times higher signal to noise ratio. This results in a better precision and lower standard deviation of the IASI retrievals. Conservatively, comparisons with CARIBIC aircraft measurements yield an averaged relative difference of 3.4 % for IASI and 4.9 % for AIRS. On average, AIRS and IASI retrievals are in very good agreement, showing the same seasonality, seasonal amplitudes, interannual variability and spatial distribution. The analysis of the monthly evolution of CO particularly highlights the expected strong influence of biomass burning on the evolution of CO in several tropical regions. In particular, a sharp increase in CO in

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“…In situ CO analysis in C1 is done using a gas chromatography (GC)-reducing gas analyser which provides measurements every 130 s with an uncertainty of ±3 nmol mol −1 (Zahn et al, 2000). In C2, a vacuum ultraviolet fluorescence (VUV) instrument with lower measurement uncertainty and higher temporal resolution of ±2 nmol mol −1 in 2 s (Scharffe et al, 2012) is employed. Furthermore, the detection frequency for O 3 mixing ratios has also increased, viz.…”

Section: On-line Instrumentationmentioning

confidence: 99%

An estimation of the <sup>18</sup>O / <sup>16</sup>O ratio of UT/LMS ozone based on artefact CO in air sampled during CARIBIC flights

Gromov

Brenninkmeijer

2015

Atmos. Chem. Phys.

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Abstract. An issue of O 3 -driven artefact production of O 3 in the upper troposphere/lowermost stratosphere (UT/LMS) air analysed in the CARIBIC-1 project is being discussed. By confronting the CO mixing and isotope ratios obtained from different analytical instrumentation, we (i) reject natural/artificial sampling and mixing effects as possible culprits of the problem, (ii) ascertain the chemical nature and quantify the strength of the contamination, and (iii) demonstrate successful application of the isotope mass-balance calculations for inferring the isotope composition of the contamination source. The δ 18 O values of the latter indicate that the oxygen is very likely being inherited from O 3 . The δ 13 C values hint at reactions of trace amounts of organics with stratospheric O 3 that could have yielded the artificial CO. While the exact contamination mechanism is not known, it is clear that the issue pertains only to the earlier (first) phase of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. Finally, estimated UT/LMS ozone δ 18 O values are lower than those observed in the stratosphere within the same temperature range, suggesting that higher pressures (240-270 hPa) imply lower isotope fractionation controlling the local δ 18 O(O 3 ) value.

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Carbon monoxide measurements onboard the CARIBIC passenger aircraft using UV resonance fluorescence

Cited by 43 publications

References 27 publications

Distribution of methane in the tropical upper troposphere measured by CARIBIC and CONTRAIL aircraft

Distribution of methane in the tropical upper troposphere measured by CARIBIC and CONTRAIL aircraft

Retrieval of tropospheric CO column from hyperspectral infrared sounders – application to four years of Aqua/AIRS and MetOp-A/IASI

An estimation of the <sup>18</sup>O / <sup>16</sup>O ratio of UT/LMS ozone based on artefact CO in air sampled during CARIBIC flights

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Carbon monoxide measurements onboard the CARIBIC passenger aircraft using UV resonance fluorescence

Cited by 43 publications

References 27 publications

Distribution of methane in the tropical upper troposphere measured by CARIBIC and CONTRAIL aircraft

Distribution of methane in the tropical upper troposphere measured by CARIBIC and CONTRAIL aircraft

Retrieval of tropospheric CO column from hyperspectral infrared sounders – application to four years of Aqua/AIRS and MetOp-A/IASI

An estimation of the &lt;sup&gt;18&lt;/sup&gt;O / &lt;sup&gt;16&lt;/sup&gt;O ratio of UT/LMS ozone based on artefact CO in air sampled during CARIBIC flights

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An estimation of the <sup>18</sup>O / <sup>16</sup>O ratio of UT/LMS ozone based on artefact CO in air sampled during CARIBIC flights