Constraints on inorganic gaseous iodine in the tropical upper troposphere and stratosphere inferred from balloon-borne solar occultation observations

Butz, A.; Bösch, H.; Camy‐Peyret, C.; Chipperfield, Martyn; Dorf, M.; Kreycy, S.; Kritten, L.; Prados-Román, C.; Schwärzle, J.; Pfeilsticker, Klaus

doi:10.5194/acp-9-7229-2009

Cited by 35 publications

(39 citation statements)

References 59 publications

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“…IO, OIO, I 2 ) species (SaizLopez et al, 2012b). Recent measurements from aircraft (Dix et al, 2013;Wang et al, 2015), balloons (Butz et al, 2009), mountain tops (Puentedura et al, 2012), ground stations (Lawler et al, 2014;Mahajan et al, 2010;Read et al, 2008), and cruises (Großmann et al, 2013;Jones et al, 2010;Mahajan et al, 2012) have enabled the development of global organic halogen emissions Ziska et al, 2013) and, more recently, data sets of IO observations with extensive geographical coverage (PradosRoman et al, 2015b;Wang et al, 2015).…”

Section: T Sherwen Et Al: Iodine's Impact On Tropospheric Oxidants:mentioning

confidence: 99%

Iodine's impact on tropospheric oxidants: a global model study in GEOS-Chem

et al. 2016

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Abstract. We present a global simulation of tropospheric iodine chemistry within the GEOS-Chem chemical transport model. This includes organic and inorganic iodine sources, standard gas-phase iodine chemistry, and simplified higher iodine oxide (I 2 O X , X = 2, 3, 4) chemistry, photolysis, deposition, and parametrized heterogeneous reactions. In comparisons with recent iodine oxide (IO) observations, the simulation shows an average bias of ∼ +90 % with available surface observations in the marine boundary layer (outside of polar regions), and of ∼ +73 % within the free troposphere (350 hPa < p < 900 hPa) over the eastern Pacific. Iodine emissions (3.8 Tg yr −1 ) are overwhelmingly dominated by the inorganic ocean source, with 76 % of this emission from hypoiodous acid (HOI). HOI is also found to be the dominant iodine species in terms of global tropospheric I Y burden (contributing up to 70 %). The iodine chemistry leads to a significant global tropospheric O 3 burden decrease (9.0 %) compared to standard GEOS-Chem (v9-2). The iodine-driven O X loss rate 1 (748 Tg O X yr −1 ) is due to photolysis of HOI (78 %), photolysis of OIO (21 %), and re- action between IO and BrO (1 %). Increases in global mean OH concentrations (1.8 %) by increased conversion of hydroperoxy radicals exceeds the decrease in OH primary production from the reduced O 3 concentration. We perform sensitivity studies on a range of parameters and conclude that the simulation is sensitive to choices in parametrization of heterogeneous uptake, ocean surface iodide, and I 2 O X (X = 2, 3, 4) photolysis. The new iodine chemistry combines with previously implemented bromine chemistry to yield a total bromine-and iodine-driven tropospheric O 3 burden decrease of 14.4 % compared to a simulation without iodine and bromine chemistry in the model, and a small increase in OH (1.8 %). This is a significant impact and so halogen chemistry needs to be considered in both climate and air quality models.

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Section: T Sherwen Et Al: Iodine's Impact On Tropospheric Oxidants:mentioning

confidence: 99%

Iodine's impact on tropospheric oxidants: a global model study in GEOS-Chem

et al. 2016

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“…Therefore, for a tighter interpretation of our data, a model with higher spatial resolution than provided by TOMCAT/SLIMCAT would be required. Such an approach is for example followed in the balloon-borne studies of Harder et al (2000), Butz et al (2009), Kreycy et al (2013), and others. However, since both processes are likely to increase the error of our analysis and since large SZA (≥ 88 • ) measurements only constitute a minor part of all measurements, we refrain from this much more complicated approach.…”

Section: Measurements and Data Reductionmentioning

confidence: 99%

Probing the subtropical lowermost stratosphere and the tropical upper troposphere and tropopause layer for inorganic bromine

et al. 2017

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Abstract. We report measurements of CH 4 (measured in situ by the Harvard University Picarro Cavity Ringdown Spectrometer (HUPCRS) and NOAA Unmanned Aircraft System Chromatograph for Atmospheric Trace Species (UCATS) instruments), O 3 (measured in situ by the NOAA dual-beam ultraviolet (UV) photometer), NO 2 , BrO (remotely detected by spectroscopic UV-visible (UV-vis) limb observations; see the companion paper of Stutz et al., 2016), and of some key brominated source gases in whole-air samples of the Global Hawk Whole Air Sampler (GWAS) instrument within the subtropical lowermost stratosphere (LS) and the tropical upper troposphere (UT) and tropopause layer (TTL). The measurements were performed within the framework of the NASA-ATTREX (National Aeronautics and Space Administration -Airborne Tropical Tropopause Experiment) project from aboard the Global Hawk (GH) during six deployments over the eastern Pacific in early 2013. These measurements are compared with TOMCAT/SLIMCAT (Toulouse Off-line Model of Chemistry And Transport/Single Layer Isentropic Model of Chemistry And Transport) 3-D model simulations, aiming at improvements of our understanding of the bromine budget and photochemistry in the LS, UT, and TTL.Changes in local O 3 (and NO 2 and BrO) due to transport processes are separated from photochemical processes in intercomparisons of measured and modeled CH 4 and O 3 . After excellent agreement is achieved among measured and simulated CH 4 and O 3 , measured and modeled [NO 2 ] are found to closely agree with ≤ 15 ppt in the TTL (which is the detection limit) and within a typical range of 70 to 170 ppt in the subtropical LS during the daytime. Measured [BrO] ranges between 3 and 9 ppt in the subtropical LS. In the TTL, [BrO] ] is found to increase from a mean of 2.63 ± 1.04 ppt for potential temperatures (θ ) in the range of 350-360 K to 5.11 ± 1.57 ppt for θ = 390 − 400 K, whereas in the subtropical LS (i.e., when [CH 4 ] ≤ 1790 ppb), it reaches 7.66 ± 2.95 ppt for θ in the range of 390-400 K. Finally, for the eastern Pacific (170-90 • W), the TOMCAT/SLIMCAT simulations indicate a net loss of ozone of −0.3 ppbv day −1 at the base of the TTL (θ = 355 K) and a net production of +1.8 ppbv day −1 in the upper part (θ = 383 K).

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“…The ensemble of scenes for which we perform retrieval simulations is the same as the one described in detail by Butz et al (2010Butz et al ( , 2012. While our former studies focus on errors induced by aerosol and cirrus scattering, we neglect such effects here; therefore we assume all scenes to be free of scattering particles.…”

Section: Satellite Retrieval and Trial Ensemblementioning

confidence: 99%

“…Therefore, considerable effort is dedicated to estimating and reducing sources of error for XCH 4 (and XCO 2 ) retrievals from solar backscatter measurements. Most studies focus on how to avoid or evaluate errors due to light-path uncertainties in light-scattering atmospheres (e.g., Frankenberg et al, 2005;Oshchepkov et al, 2008;Butz et al, 2009Butz et al, , 2010Reuter et al, 2010;O'Dell et al, 2012;Buchwitz et al, 2013). In particular, Butz et al (2012) assess the residual aerosol-and cirrusinduced XCH 4 retrieval errors for an S5P-like observer using a global and seasonal ensemble of simulated S5P measurements.…”

Section: R Checa-garcia Et Al: Spectroscopic Uncertainties For Ch 4mentioning

confidence: 99%

Mapping spectroscopic uncertainties into prospective methane retrieval errors from Sentinel-5 and its precursor

et al. 2015

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Abstract. and its precursor (S5P) are future European satellite missions aiming at global monitoring of methane (CH 4 ) column-average dry air mole fractions (XCH 4 ). The spectrometers to be deployed onboard the satellites record spectra of sunlight backscattered from the Earth's surface and atmosphere. In particular, they exploit CH 4 absorption in the shortwave infrared spectral range around 1.65 µm (S5 only) and 2.35 µm (both S5 and S5P) wavelength. Given an accuracy goal of better than 2 % for XCH 4 to be delivered on regional scales, assessment and reduction of potential sources of systematic error such as spectroscopic uncertainties is crucial. Here, we investigate how spectroscopic errors propagate into retrieval errors on the global scale. To this end, absorption spectra of a groundbased Fourier transform spectrometer (FTS) operating at very high spectral resolution serve as estimate for the quality of the spectroscopic parameters. Feeding the FTS fitting residuals as a perturbation into a global ensemble of simulated S5-and S5P-like spectra at relatively low spectral resolution, XCH 4 retrieval errors exceed 0.6 % in large parts of the world and show systematic correlations on regional scales, calling for improved spectroscopic parameters.

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Constraints on inorganic gaseous iodine in the tropical upper troposphere and stratosphere inferred from balloon-borne solar occultation observations

Cited by 35 publications

References 59 publications

Iodine's impact on tropospheric oxidants: a global model study in GEOS-Chem

Iodine's impact on tropospheric oxidants: a global model study in GEOS-Chem

Probing the subtropical lowermost stratosphere and the tropical upper troposphere and tropopause layer for inorganic bromine

Mapping spectroscopic uncertainties into prospective methane retrieval errors from Sentinel-5 and its precursor

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