Evaluation of source gas lifetimes from stratospheric observations

Volk, C. M.; Elkins, James W.; Fahey, D. W.; Dutton, G. S.; Gilligan, Jonathan M.; Loewenstein, M.; Podolske, J. R.; Chan, K. R.; Gunson, M. R.

doi:10.1029/97jd02215

Cited by 234 publications

(288 citation statements)

References 71 publications

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“…Long-lived species with tropospheric sources, such as N2O and CH4, are very stable in the troposphere (with longer than a decade), but become slightly unstable with height. The estimated for these species are similar to those from previous studies (e.g., Volk et al 1997). Figure 3 presents a scatter diagram of and Kyy for various chemical species in the middle stratosphere and middle/upper troposphere at mid-latitudes.…”

Section: Dependency Of Kyy On the Chemical Lifetimesupporting

confidence: 75%

Isentropic Diffusion Coefficient Derived from Chemical Constituent Data

Miyazaki

Iwasaki

2009

SOLA

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The isentropic diffusion coefficient (Kyy) characterizes large-scale atmospheric mixing processes. Chemical constituents allow us to directly estimate Kyy from observational data sets. This study investigates general aspects of the mixing processes from a systematic survey of the common features and constituent dependency of Kyy . Analysis with chemical constituent data obtained from a global chemical transport model demonstrates that long-lived species whose chemical lifetimes ( ) are several years long have very common seasonal and latitudinal variations of Kyy, which is considered to represent actual atmospheric mixing. Kyy, estimated from chemical species with shorter than several weeks, becomes considerably greater than that from long-lived species and indicates the significance of nonlinear effects. Meridional transport analysis also investigates that shorter results in greater spatial constituent variations and larger contributions of the eddy compared to the mean motions in the constituent transport flux. IntroductionLarge-scale isentropic eddy mixing plays an important role in determining constituent distribution (e.g., Plumb 2007). Isentropic mixing due to planetary wave breaking causes significant mixing in the stratospheric "surf zone" (McIntyre and Palmer 1984), while synopticscale disturbance, caused by baroclinic waves, disperses air along isentropes in the extratropical troposphere (e.g., Kida 1980). These mixings increase the constituent gradients over isentropic surfaces at the edge of the mixing region, but decrease them within the mixing region (e.g., Juckes and McIntyre 1987;Miyazaki and Iwasaki 2008).The eddy diffusion coefficient has been widely used to characterize mixing processes. The adiabatic component of the eddy diffusion coefficient, Kyy, reflects wave motions of the atmosphere since the eddy transport is almost parallel to the isentropic surface, particularly in the stratosphere. Kyy has also been used to parameterize the Rossby wave mixing in two-dimensional chemical transport models (CTMs, e.g., Garcia and Solomon 1983). Kyy is generally diagnosed using the potential vorticity (PV) flux (Newman et al. 1988) since the PV acts as a conservative passive tracer for adiabatic and frictionless flow. Magnitude of the diffusion coefficient also can be measured by ideal passive tracer calculations. However, it is difficult to directly estimate the PV flux from any observation, and calculations of the PV flux or an ideal passive tracer can suffer from numerical error. Instead of using the PV flux or the ideal passive tracer, some studies have used the distributions of specific long-lived species such as N2O and CH4 to investigate atmospheric transport and mixing processes (e.g., Lingenfelser and Grose 2002). Although long-lived species allow us to directly estimate Kyy from observational data sets, the sensitivity of Kyy to chemical species has not been clearly understood.In this study, we investigate the common features and constituent dependency of Kyy to facilitate understandin...

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Section: Dependency Of Kyy On the Chemical Lifetimesupporting

confidence: 75%

Isentropic Diffusion Coefficient Derived from Chemical Constituent Data

Miyazaki

Iwasaki

2009

SOLA

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“…Photolytic processes in the stratosphere provide the major sink for N 2 O and the loss rate, corresponding to a lifetime of about 120 years, can be defined with considerable confidence [Volk et al, 1997]. Assuming a steady state balance of production and loss of N 2 O in the pre-anthropogenic environment since the last interglacial period, as suggested by the ice core measurements [Sowers, 2001], the pre-anthropogenic source is estimated at 10.9 TgN yr À1 .…”

Section: Microbial Processesmentioning

confidence: 99%

Human and animal wastes: Implications for atmospheric N₂O and NO_x

Chen

Wang

2005

Global Biogeochemical Cycles

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[1] More than 220 Tg N are processed annually through the global agriculture/animal/ human food chain. It is suggested that aerobic denitrification, reduction of nitrite formed in the first stage of nitrification, is an important source not only of global N 2 O but also of NO x . A simple top-down method indicates a globally averaged yield of 2% for N 2 O emitted as a consequence of human disturbances to the global nitrogen cycle. This yield can account not only for the contemporary budget of atmospheric N 2 O but also for trends observed over the past 1000 years. The associated microbial source of NO x is estimated assuming a NO x /N 2 O ratio of 3, consistent with results from a variety of laboratory and field studies. This source is significant, particularly for large developing countries such as China and India for which its contribution is comparable to that from fossil fuel.

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“…Generally, it is not possible to diagnose AoA or an acceleration of the BDC solely from a time series of a chemical tracer like CH 4 because its mixing ratio, χ (r, t), at a specific location r in the stratosphere is the integral of the product in expression (1) below for all past times t from −∞ to t, where χ o (t ) is the time series for CH 4 in the troposphere, G(r, t ) is the stratospheric age spectra or transit time distribution (its first moment being the mean AoA), and L(r, t ) is its loss function that depends on the path spectra and the chemical sink distribution for CH 4 in the stratosphere (Volk et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere

Remsberg

2015

Atmos. Chem. Phys.

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Abstract. This study makes use of time series of methane (CH 4 ) data from the Halogen Occultation Experiment (HALOE) to detect whether there were any statistically significant changes of the Brewer-Dobson circulation (BDC) within the stratosphere during 1992-2005. The HALOE CH 4 profiles are in terms of mixing ratio versus pressure altitude and are binned into latitude zones within the Southern Hemisphere and the Northern Hemisphere. Their separate time series are then analyzed using multiple linear regression (MLR) techniques. The CH 4 trend terms for the Northern Hemisphere are significant and positive at 10 • N from 50 to 7 hPa and larger than the tropospheric CH 4 trends of about 3 % decade −1 from 20 to 7 hPa. At 60 • N the trends are clearly negative from 20 to 7 hPa. Their combined trends indicate an acceleration of the BDC in the middle stratosphere of the Northern Hemisphere during those years, most likely due to changes from the effects of wave activity. No similar significant BDC acceleration is found for the Southern Hemisphere. Trends from HALOE H 2 O are analyzed for consistency. Their mutual trends with CH 4 are anti-correlated qualitatively in the middle and upper stratosphere, where CH 4 is chemically oxidized to H 2 O. Conversely, their mutual trends in the lower stratosphere are dominated by their trends upon entry to the tropical stratosphere. Time series residuals for CH 4 in the lower mesosphere also exhibit structures that are anti-correlated in some instances with those of the tracer-like species HCl. Their occasional aperiodic structures indicate the effects of transport following episodic, wintertime wave activity. It is concluded that observed multi-year, zonally averaged distributions of CH 4 can be used to diagnose major instances of wave-induced transport in the middle atmosphere and to detect changes in the stratospheric BDC.

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Evaluation of source gas lifetimes from stratospheric observations

Cited by 234 publications

References 71 publications

Isentropic Diffusion Coefficient Derived from Chemical Constituent Data

Isentropic Diffusion Coefficient Derived from Chemical Constituent Data

Human and animal wastes: Implications for atmospheric N₂O and NO_x

Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere

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Evaluation of source gas lifetimes from stratospheric observations

Cited by 234 publications

References 71 publications

Isentropic Diffusion Coefficient Derived from Chemical Constituent Data

Isentropic Diffusion Coefficient Derived from Chemical Constituent Data

Human and animal wastes: Implications for atmospheric N2O and NOx

Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere

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Product

Resources

About

Human and animal wastes: Implications for atmospheric N₂O and NO_x