Compact highly sensitive multi-species airborne mid-IR spectrometer

Richter, Dirk; Weibring, Petter; Walega, J.; Fried, Alan; Spuler, Scott M.; Taubman, Matthew S.

doi:10.1007/s00340-015-6038-8

Cited by 93 publications

(84 citation statements)

References 20 publications

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“…Figure 4 shows the simulated and observed CDFs of NO x , isoprene, formaldehyde, and ozone concentrations sampled along the flight tracks in the Southeast US mixed layer. Formaldehyde was measured by the Compact Atmospheric Multispecies Spectrometer (CAMS) (Richter et al, 2015) and ozone by chemiluminescence (Ryerson et al, 2000). NO x and isoprene are primary (directly emitted) and have mean lifetimes against chemical loss of a few hours and less than an hour, respectively.…”

Section: Methodsmentioning

confidence: 99%

Sensitivity to grid resolution in the ability of a chemical transport model to simulate observed oxidant chemistry under high-isoprene conditions

Jacob

Fisher

et al. 2016

Atmos. Chem. Phys.

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Abstract. Formation of ozone and organic aerosol in continental atmospheres depends on whether isoprene emitted by vegetation is oxidized by the high-NO x pathway (where peroxy radicals react with NO) or by low-NO x pathways (where peroxy radicals react by alternate channels, mostly with HO 2 ). We used mixed layer observations from the SEAC 4 RS aircraft campaign over the Southeast US to test the ability of the GEOS-Chem chemical transport model at different grid resolutions (0.25to simulate this chemistry under high-isoprene, variable-NO x conditions. Observations of isoprene and NO x over the Southeast US show a negative correlation, reflecting the spatial segregation of emissions; this negative correlation is captured in the model at 0.25 • × 0.3125 • resolution but not at coarser resolutions. As a result, less isoprene oxidation takes place by the high-NO x pathway in the model at 0.25 • × 0.3125 • resolution (54 %) than at coarser resolution (59 %). The cumulative probability distribution functions (CDFs) of NO x , isoprene, and ozone concentrations show little difference across model resolutions and good agreement with observations, while formaldehyde is overestimated at coarse resolution because excessive isoprene oxidation takes place by the high-NO x pathway with high formaldehyde yield. The good agreement of simulated and observed concentration variances implies that smaller-scale non-linearities (urban and power plant plumes) are not important on the regional scale. Correlations of simulated vs. observed concentrations do not improve with grid resolution because finer modes of variability are intrinsically more difficult to capture. Higher model resolution leads to decreased conversion of NO x to organic nitrates and increased conversion to nitric acid, with total reactive nitrogen oxides (NO y ) changing little across model resolutions. Model concentrations in the lower free troposphere are also insensitive to grid resolution. The overall low sensitivity of modeled concentrations to grid resolution implies that coarse resolution is adequate when modelPublished by Copernicus Publications on behalf of the European Geosciences Union. K. Yu et al.: Sensitivity to grid resolution under high-isoprene conditionsing continental boundary layer chemistry for global applications.

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Section: Methodsmentioning

confidence: 99%

Sensitivity to grid resolution in the ability of a chemical transport model to simulate observed oxidant chemistry under high-isoprene conditions

Jacob

Fisher

et al. 2016

Atmos. Chem. Phys.

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“…The auxiliary gas-phase data used in this analysis are carbon monoxide (CO) by vacuum UV resonance fluorescence (Gerbig et al, 1999); nitric oxide (NO) and nitrogen dioxide (NO 2 ) by chemiluminescence (Ridley et al, 2004); ethane (C 2 H 6 ) by infrared spectrometry (Richter et al, 2015); aromatic and biogenic species by online proton-transfer-reaction mass spectrometry (Lindinger et al, 1998;de Gouw and Warneke, 2007); hydrogen cyanide (HCN); i-pentane and npentane by online cryogenic gas chromatography-mass spectrometry (GC-MS) (Apel et al, 2015); methylcyclohexane and n-octane by offline analysis of whole air canister samples (WAS) by GC-MS (Colman et al, 2001); nitric acid (HNO 3 ) by chemical ionization mass spectrometry (CIMS) using SF − 6 as the reagent ion (Huey et al, 1998); peroxyacyl nitrates (PAN and PPN) by I − CIMS (Zheng et al, 2011); alkyl nitrates by thermal dissociation laser-induced fluorescence (Day et al, 2002); and hydroxyl (OH), hydroperoxy (HO 2 ), and alkyl peroxy (RO 2 ) radicals by CIMS (Mauldin et al, 1998;Hornbrook et al, 2011;Ren et al, 2012). NO y was calculated by summing up the individually measured nitrogen oxide species, namely NO, NO 2 , HNO 3 , particulate nitrate, PAN, PPN, and alkyl nitrates.…”

Section: Measurementsmentioning

confidence: 99%

Sources and characteristics of summertime organic aerosol in the Colorado Front Range: perspective from measurements and WRF-Chem modeling

et al. 2018

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Abstract. The evolution of organic aerosols (OAs) and their precursors in the boundary layer (BL) of the Colorado Front Range during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ, July-August 2014) was analyzed by in situ measurements and chemical transport modeling. Measurements indicated significant production of secondary OA (SOA), with enhancement ratio of OA with respect to carbon monoxide (CO) reaching 0.085 ± 0.003 µg m −3 ppbv −1 . At background mixing ratios of CO, up to ∼ 1.8 µg m −3 background OA was observed, suggesting significant non-combustion contribution to OA in the Front Range. The mean concentration of OA in plumes with a high influence of oil and natural gas (O&G) emissions was ∼ 40 % higher than in urban-influenced plumes. Positive matrix factorization (PMF) confirmed a dominant contribution of secondary, oxygenated OA (OOA) in the boundary layer instead of fresh, hydrocarbon-like OA (HOA). Combinations of primary OA (POA) volatility assumptions, aging of semivolatile species, and different emission estimates from the O&G sector were used in the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) simulation scenarios. The assumption of semi-volatile POA resulted in greater than a factor of 10 lower POA concentrations compared to PMF-resolved HOA. Including top-down modified O&G emissions resulted in substantially better agreements in modeled ethane, toluene, hydroxyl radical, and ozone compared to measurements in the high-O&G-influenced plumes. By including emissions from the O&G sector using the topdown approach, it was estimated that the O&G sector contributed to < 5 % of total OA, but up to 38 % of anthropogenic SOA (aSOA) in the region. The best agreement between the measured and simulated median OA was achieved by limiting the extent of biogenic hydrocarbon aging and consequently biogenic SOA (bSOA) production. Despite a Published by Copernicus Publications on behalf of the European Geosciences Union.

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“…HCHO was measured in SEAC 4 RS by two different techniques: mid-IR absorption spectroscopy using the CAMS (Richter et al, 2015), and laser-induced fluorescence using the NASA GSFC ISAF (Cazorla et al, 2015). The two measurements are well correlated (r = 0.96 in the mixed layer), with ISAF ~10% higher than CAMS measurements .…”

Section: Comparisons With Seac 4 Rs Datamentioning

confidence: 99%

High-resolution inversion of OMI formaldehyde columns to quantify isoprene emission on ecosystem-relevant scales: application to the Southeast US

Kaiser¹,

Jacob²,

Zhu³

et al. 2017

Preprint

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Abstract. Isoprene emissions from vegetation have a large effect on atmospheric chemistry and air quality. isoprene emission inventories used in atmospheric models are based on limited vegetation information and uncertain land cover data, leading to potentially large errors. Satellite observations of atmospheric formaldehyde (HCHO), a high-yield isoprene oxidation product, provide 'top-down' information to evaluate isoprene emission inventories through inverse analyses. Past inverse analyses have however been hampered by uncertainty in the HCHO satellite data, uncertainty in the time-and NO x -dependent yield of HCHO from isoprene oxidation, and coarse resolution of the atmospheric models used for 30 the inversion. Here we demonstrate the ability to use HCHO satellite data from OMI in a high-resolution inversion to 2 to correct model NO x biases, which was done here using SEAC 4 RS observations but can be done more generally using satellite NO 2 data concurrently with HCHO. We find in our inversion that isoprene emissions from the widely-used MEGAN v2.1 inventory are biased high over the Southeast US by 40% on average, although the broad-scale distributions are correct including maximum emissions in Arkansas/Louisiana and high base emission factors in the oak-covered Ozarks of Southeast Missouri. A particularly large discrepancy is in the Edwards Plateau of Central Texas where MEGAN v2.1 is too high by a 5 factor of 3, possibly reflecting errors in land cover. The lower isoprene emissions inferred from our inversion, when implemented into GEOS-Chem, decrease surface ozone over the Southeast US by 1-3 ppb and decrease the isoprene contribution to organic aerosol from 40% to 20%.

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Compact highly sensitive multi-species airborne mid-IR spectrometer

Cited by 93 publications

References 20 publications

Sensitivity to grid resolution in the ability of a chemical transport model to simulate observed oxidant chemistry under high-isoprene conditions

Sensitivity to grid resolution in the ability of a chemical transport model to simulate observed oxidant chemistry under high-isoprene conditions

Sources and characteristics of summertime organic aerosol in the Colorado Front Range: perspective from measurements and WRF-Chem modeling

High-resolution inversion of OMI formaldehyde columns to quantify isoprene emission on ecosystem-relevant scales: application to the Southeast US

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