Influence of convection on the water isotopic composition of the tropical tropopause layer and tropical stratosphere

Sayres, D. S.; Pfister, Leonhard; Hanisco, T. F.; Moyer, E. J.; Smith, J. B.; Clair, Jason M. St.; O’Brien, Anne; Witinski, Mark F.; Legg, M.; Anderson, James G.

doi:10.1029/2009jd013100

Cited by 59 publications

(94 citation statements)

References 41 publications

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“…During the wet season, moist air is frequently transported from interior South America by the Bolivian High, a feature associated with the South American monsoon [Lenters and Cook, 1997]. Galewsky et al [2011] showed that dry air from the upper tropical troposphere (UT) reaches the surface at Chajnantor, with mixing ratios as low as 215 ppmv and water vapor D values as low as −540‰, values that are consistent with aircraft measurements from the upper troposphere [Sayres et al, 2010]. They further showed that this dry UT air mixes with moister air from the middle and lower troposphere.…”

Section: The Chajnantor Plateausupporting

confidence: 55%

“…The isotopic composition of water vapor in the stratosphere has been the subject of much debate, because Rayleigh distillation predicts D < −800‰ at the mixing ratios encountered in the lower stratosphere, but measurements indicate −700‰ ≤ D ≤ −550‰ [Sayres et al, 2010;Kuang et al, 2003]. These discrepancies between the Rayleigh model and observations have been interpreted in terms of kinetic fractionation processes in deep convection [Bolot et al, 2013], convective detrainment [Moyer et al, 1996;Kuang et al, 2003;Bony et al, 2008], or mixing [Dessler and Sherwood, 2003].…”

Section: Stable Isotopic Composition Of Water Vapormentioning

confidence: 99%

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Water vapor isotopic composition of a stratospheric air intrusion: Measurements from the Chajnantor Plateau, Chile

Galewsky

Samuels-Crow

2014

JGR Atmospheres

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Measurements of water vapor isotopic composition in stratospheric air intrusions can be used to constrain the dilution of the intrusion as it mixes into the middle troposphere. The intrusion studied here occurred on 17 and 18 August 2012 with measurements obtained at an altitude of 5 km in the Chilean Andes at the Atacama Large Millimeter Array astronomical observatory on the Chajnantor Plateau. Surface ozone concentrations rose 16 ppb in 6 h and were associated with a potential vorticity intrusion on the 330 K isentropic surface. A simulated stratospheric ozone tracer reaching Chajnantor also supports the interpretation of a stratospheric intrusion. Beginning around 18:00 UTC on 17 August, the mixing ratio dropped from 3000 ppmv to 430 ppmv as the water vapor δD values dropped from −153‰ to −438‰ over 13 h while the δ18O values dropped from −20‰ to −63‰. The average mixing ratio, δD, and δ18O values during August 2012 were measured to be 1500 ppmv, −250‰, and −34‰, respectively. The minimum water vapor concentration during the intrusion was in the driest 5% of measurements made during that month, while the minimum δD and δ18O values were within the lowest 0.5% of measurements made during that month. Simple two‐component models of mixing between stratospheric or upper tropospheric air with boundary layer air fail to reproduce observations, but a three‐component mixing model, in which the stratospheric intrusion mixes with an upper tropospheric background air mass, as it mixes with boundary layer air on Chajnantor, matches the observations.

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Section: The Chajnantor Plateausupporting

confidence: 55%

Section: Stable Isotopic Composition Of Water Vapormentioning

confidence: 99%

Water vapor isotopic composition of a stratospheric air intrusion: Measurements from the Chajnantor Plateau, Chile

Galewsky

Samuels-Crow

2014

JGR Atmospheres

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“…Planned applications for the LTDs beyond Match calculations include the quantification of convective influence to tropical and subtropical upper tropospheric air masses observed by MLS, as previously implemented for highaltitude aircraft in situ observations (Pfister et al, 2001Sayres et al, 2010), and the generation of high resolution "trajectory-mapped" fields such as previously implemented by Schoeberl et al (2007).…”

Section: Appendix A: Mls Lagrangian Trajectory Diagnosticsmentioning

confidence: 99%

A Match-based approach to the estimation of polar stratospheric ozone loss using Aura Microwave Limb Sounder observations

2015

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Abstract. The well-established "Match" approach to quantifying chemical destruction of ozone in the polar lower stratosphere is applied to ozone observations from the Microwave Limb Sounder (MLS) on NASA's Aura spacecraft. Quantification of ozone loss requires distinguishing transport-and chemically induced changes in ozone abundance. This is accomplished in the Match approach by examining cases where trajectories indicate that the same air mass has been observed on multiple occasions. The method was pioneered using ozonesonde observations, for which hundreds of matched ozone observations per winter are typically available. The dense coverage of the MLS measurements, particularly at polar latitudes, allows matches to be made to thousands of observations each day. This study is enabled by recently developed MLS Lagrangian trajectory diagnostic (LTD) support products. Sensitivity studies indicate that the largest influence on the ozone loss estimates are the value of potential vorticity (PV) used to define the edge of the polar vortex (within which matched observations must lie) and the degree to which the PV of an air mass is allowed to vary between matched observations. Applying Match calculations to MLS observations of nitrous oxide, a long-lived tracer whose expected rate of change is negligible on the weekly to monthly timescales considered here, enables quantification of the impact of transport errors on the Match-based ozone loss estimates. Our loss estimates are generally in agreement with previous estimates for selected Arctic winters, though indicating smaller losses than many other studies. Arctic ozone losses are greatest during the 2010/11 winter, as seen in prior studies, with 2.0 ppmv (parts per million by volume) loss estimated at 450 K potential temperature ( ∼ 18 km altitude).As expected, Antarctic winter ozone losses are consistently greater than those for the Arctic, with less interannual variability (e.g., ranging between 2.3 and 3.0 ppmv at 450 K). This study exemplifies the insights into atmospheric processes that can be obtained by applying the Match methodology to a densely sampled observation record such as that from Aura MLS.

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“…In the upper troposphere, the water vapor isotopic composition can be measured by satellites (Kuang et al, 2003;Nassar et al, 2007;Steinwagner et al, 2010) or in situ (Webster and Heymsfield, 2003;Sayres et al, 2010) and reflects the role of convection in the transport of water in the upper troposphere and through the tropopause (Moyer et al, 1996). In the mid-troposphere, the water vapor isotopic composition can also be measured by satellite (Worden et al, 2007;Herbin et al, 2009;Schneider and Hase, 2011) and in situ and may give an indication about water cycle processes such as mixing of air masses (Galewsky and Hurley, 2010) or rain reevaporation (Worden et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Water vapor isotopologue retrievals from high-resolution GOSAT shortwave infrared spectra

et al. 2013

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Remote sensing of the isotopic composition of water vapor can provide valuable information on the hydrological cycle. Here, we demonstrate the feasibility of retrievals of the relative abundance of HDO (the HDO/H2O ratio) from the Japanese GOSAT satellite. For this purpose, we use high spectral resolution nadir radiances around 6400 cm−1 (1.56 μm) to retrieve vertical column amounts of H2O and HDO. Retrievals of H2O correlate well with ECMWF (European Centre for Medium-Range Weather Forecasts) integrated profiles (r2 = 0.96). Typical precision errors in the retrieved column-averaged deuterium depletion (δD) are 20–40&permil;. We compare δD against a TCCON (Total Carbon Column Observing Network) ground-based station in Lamont, Oklahoma. Using retrievals in very dry areas over Antarctica, we detect a small systematic offset in retrieved H2O and HDO column amounts and take this into account for a bias correction of δD. Monthly averages of δD in the June 2009 to September 2011 time frame are well correlated with TCCON (r2 = 0.79) and exhibit a slope of 0.98 (1.23 if not bias corrected). We also compare seasonal averages on the global scale with results from the SCIAMACHY instrument in the 2003–2005 time frame. Despite the lack of temporal overlap, seasonal averages in general agree well, with spatial correlations (r2) ranging from 0.62 in September through November to 0.83 in June through August. However, we observe higher variability in GOSAT δD, indicated by fitted slopes between 1.2 and 1.46. The discrepancies are likely related to differences in vertical sensitivities but warrant further validation of both GOSAT and SCIAMACHY and an extension of the validation dataset

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Influence of convection on the water isotopic composition of the tropical tropopause layer and tropical stratosphere

Cited by 59 publications

References 41 publications

Water vapor isotopic composition of a stratospheric air intrusion: Measurements from the Chajnantor Plateau, Chile

Water vapor isotopic composition of a stratospheric air intrusion: Measurements from the Chajnantor Plateau, Chile

A Match-based approach to the estimation of polar stratospheric ozone loss using Aura Microwave Limb Sounder observations

Water vapor isotopologue retrievals from high-resolution GOSAT shortwave infrared spectra

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