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Prinn, RG, Zander R, Cunnold DM, Elkins JW, Engel A, Fraser PJ, Gunson MR, Ko MKW, Mahieu E, Midgley PM, Russel III JM, Volk CM, Weiss RF.  1999.  Long-lived ozone-related compounds. Scientific assessment of ozone depletion, 1998 (World Meteorological Organization, Global Ozone Research and Monitoring Project Report 44). :54., Washington, DC: National Oceanic and Atmospheric Administration Abstract
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Reimann, S, Manning AJ, Simmonds PG, Cunnold DM, Wang RHJ, Li JL, McCulloch A, Prinn RG, Huang J, Weiss RF, Fraser PJ, O'Doherty S, Greally BR, Stemmler K, Hill M, Folini D.  2005.  Low European methyl chloroform emissions inferred from long-term atmospheric measurements. Nature. 433:506-508.   10.1038/nature03220   AbstractWebsite

Methyl chloroform (CH3CCl3, 1,1,1,-trichloroethane) was used widely as a solvent before it was recognized to be an ozone-depleting substance and its phase-out was introduced under the Montreal Protocol(1). Subsequently, its atmospheric concentration has declined steadily(2-4) and recent European methyl chloroform consumption and emissions were estimated to be less than 0.1 gigagrams per year(1,5). However, data from a short-term tropospheric measurement campaign ( EXPORT) indicated that European methyl chloroform emissions could have been over 20 gigagrams in 2000 (ref. 6), almost doubling previously estimated global emissions(1,4). Such enhanced emissions would significantly affect results from the CH3CCl3 method of deriving global abundances of hydroxyl radicals ( OH) (refs 7 - 12) - the dominant reactive atmospheric chemical for removing trace gases related to air pollution, ozone depletion and the greenhouse effect. Here we use long-term, high-frequency data from MaceHead, Ireland and Jungfraujoch, Switzerland, to infer European methyl chloroform emissions. We find that European emission estimates declined from about 60 gigagrams per year in the mid-1990s to 0.3 - 1.4 and 1.9 - 3.4 gigagrams per year in 2000 - 03, based on Mace Head and Jungfraujoch data, respectively. Our European methyl chloroform emission estimates are therefore higher than calculated from consumption data(1,5), but are considerably lower than those derived from the EXPORT campaign in 2000 ( ref. 6).

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Falkner, KK, Measures CI, Herbelin SE, Edmond JM, Weiss RF.  1991.  The major and minor element geochemistry of Lake Baikal. Limnology and Oceanography. 36:413-423. AbstractWebsite

A comprehensive, joint Soviet-American study of the chemistry of Lake Baikal, the world's deepest (1,632 m) lake, was carried out in July 1988. In this paper, we report the major, minor, and preliminary trace element concentrations for three profiles obtained at or near the deepest and central part of the three major basins of the lake. With the exception of Ba, the distributions of major and minor elements were homogeneous, displaying no variations greater than analytical uncertainties. Average concentrations in mu-mol kg-1 (1 SD) are titration alkalinity = 1,093(6), SO42- = 57.4(1.3), Cl = 12.3(0.7), Ca = 402(7), Mg = 126(1), Na = 155(4), and K = 24.1(1.0); and in nmol kg-1 are Sr = 1,350(30), Li = 296(12), Ba = 74.7(2.6), Rb = 7.10(0.23), and U = 1.77(0.12). Excluding K and Cl, these values compare favorably with previously published results. Although some hydrothermal activity is known to occur within the lake, it does not appear to significantly affect major ion cycling. The residence times of the major ions are 330 yr or the same as that of water in the basin and so are controlled predominantly by their riverine fluxes. There is not yet enough information to assess whether hydrothermal processes affect minor element cycles. Ba concentrations decrease with depth, showing abrupt decreases near the bottom at two stations. It appears to undergo some form of uptake at the sediments, but further study is required to discern the processes governing Ba distribution.

Lupton, JE, Weiss RF, Craig H.  1977.  Mantle helium in hydrothermal plumes in the Galapagos Rift. Nature. 267:603-604.   10.1038/267603a0   AbstractWebsite

THE 3He/4He ratio in deep Pacific water is 20–30% higher than in atmospheric helium because of injection of primordial helium from the mantle1,2. The largest 3He enrichments in the Pacific have been found in water on the crest of the East Pacific Rise where the isotopic ratios indicate2 that the excess helium component has a 3He/4He ratio about ten times the atmospheric ratio, in agreement with the ratios measured in trapped helium in the glassy rims of oceanic tholeiites3,4. Recent measurements in this laboratory5 have shown that the hot brines in the axial rift of the Red Sea are very highly enriched in mantle helium. 3He and 4He are respectively 3300 and 380 times supersaturated relative to atmospheric solubility equilibrium in seawater, with a 3He/4He ratio of 1.2×10−5, or 8.6 times the ratio in atmospheric helium. Comparison of the enrichments of various elements in the Red Sea brines and in brines associated with salt domes6 shows that helium is the only component in the Red Sea brines which unequivocally requires derivation from hydrothermal circulation of seawater in basalts. The helium isotopes are thus an extremely powerful and sensitive tracer for the detection and mapping of hydrothermal systems in oceanic spreading centres.

Lupton, JE, Weiss RF, Craig H.  1977.  Mantle helium in the Red Sea brines. Nature. 266:244-246.   10.1038/266244a0   AbstractWebsite

HELIUM isotope studies on terrestrial samples have revealed the existence of two helium components which are clearly distinct from atmospheric helium. The first of these, which we term ‘crustal helium’, was identified in 1946 in natural gas wells1. This crustal component is produced by radioactive decay of U and Th to 4He, with 3He production by (n, α) reactions on Li; the resulting helium is characterised by 3He/4He ≃ 10−7, one-tenth of the atmospheric ratio2. The second component, ‘mantle helium’, was discovered as ‘excess 3He’ in deep ocean water, attributed to a flux of primordial helium from the mantle3. Studies of the 3He/4He ratio in deep water on the East Pacific Rise4 and in helium trapped in submarine basalt glasses5,6 have shown that this mantle component is characterised by 3He/4He ≃ 10−5, about 10 times the atmospheric ratio and 100 times the ratio in crustal helium. Basalt glasses from the Western Pacific Lau Basin, the East Pacific Rise, and the Mid-Atlantic Ridge contain trapped helium with similar 3He/4He ratios, indicating that mantle helium in at least three areas in which new lithosphere is being formed has a unique and uniform isotopic signature.

Petrenko, VV, Severinghaus JP, Schaefer H, Smith AM, Kuhl T, Baggenstos D, Hua Q, Brook EJ, Rose P, Kulin R, Bauska T, Harth C, Buizert C, Orsi A, Emanuele G, Lee JE, Brailsford G, Keeling R, Weiss RF.  2016.  Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates. Geochimica et Cosmochimica Acta. 177:62-77.   10.1016/j.gca.2016.01.004   Abstract

Carbon-14 (14C) is incorporated into glacial ice by trapping of atmospheric gases as well as direct near-surface in situ cosmogenic production. 14C of trapped methane (14CH4) is a powerful tracer for past CH4 emissions from “old” carbon sources such as permafrost and marine CH4 clathrates. 14C in trapped carbon dioxide (14CO2) can be used for absolute dating of ice cores. In situ produced cosmogenic 14C in carbon monoxide (14CO) can potentially be used to reconstruct the past cosmic ray flux and past solar activity. Unfortunately, the trapped atmospheric and in situ cosmogenic components of 14C in glacial ice are difficult to disentangle and a thorough understanding of the in situ cosmogenic component is needed in order to extract useful information from ice core 14C. We analyzed very large (≈1000 kg) ice samples in the 2.26–19.53 m depth range from the ablation zone of Taylor Glacier, Antarctica, to study in situ cosmogenic production of 14CH4 and 14CO. All sampled ice is >50 ka in age, allowing for the assumption that most of the measured 14C originates from recent in situ cosmogenic production as ancient ice is brought to the surface via ablation. Our results place the first constraints on cosmogenic 14CH4 production rates and improve on prior estimates of 14CO production rates in ice. We find a constant 14CH4/14CO production ratio (0.0076 ± 0.0003) for samples deeper than 3 m, which allows the use of 14CO for correcting the 14CH4 signals for the in situ cosmogenic component. Our results also provide the first unambiguous confirmation of 14C production by fast muons in a natural setting (ice or rock) and suggest that the 14C production rates in ice commonly used in the literature may be too high.

Miller, BR, Weiss RF, Salameh PK, Tanhua T, Greally BR, Muhle J, Simmonds PG.  2008.  Medusa: A sample preconcentration and GC/MS detector system for in situ measurements of atmospheric trace halocarbons, hydrocarbons, and sulfur compounds. Analytical Chemistry. 80:1536-1545.   10.1021/ac702084k   AbstractWebsite

Significant changes have occurred in the anthropogenic emissions of many compounds related to the Kyoto and Montreal Protocols within the past 20 years and many of their atmospheric abundances have responded dramatically. Additionally, there are a number of related natural compounds with underdetermined source or sink budgets. A new instrument, Medusa, was developed to make the high frequency in situ measurements required for the determination of the atmospheric lifetimes and emissions of these compounds. This automated system measures a wide range of halocarbons, hydrocarbons, and sulfur compounds involved in ozone depletion and/or climate forcing, from the very volatile perfluorocarbons (PFCs, e.g., CF(4) and CF(3)CF(3)) and hydrofluorocarbons (HFCs, e.g., CH(3)CF(3)) to the higher-boiling point solvents (such as CH(3)CCl(3) and CCl(2)= CCl(2)) and CHBr(3). A network of Medusa systems worldwide provides 12 in situ ambient air measurements per day of more than 38 compounds of part per trillion mole fractions and precisions up to 0.1% RSD at the five remote field stations operated by the Advanced Global Atmospheric Gases Experiment (AGAGE). Ihis custom system couples gas chromatography/mass spectrometry (GC/MSD) with a novel scheme for cryogen-free low-temperature preconcentration (-165 degrees C) of analytes from 2 L samples in a two-trap process using HayeSep D adsorbent.

Thompson, RL, Stohl A, Zhou LX, Dlugokencky E, Fukuyama Y, Tohjima Y, Kim SY, Lee H, Nisbet EG, Fisher RE, Lowry D, Weiss RF, Prinn RG, O'Doherty S, Young D, White JWC.  2015.  Methane emissions in East Asia for 2000-2011 estimated using an atmospheric Bayesian inversion. Journal of Geophysical Research-Atmospheres. 120:4352-4369.   10.1002/2014jd022394   AbstractWebsite

We present methane (CH4) emissions for East Asia from a Bayesian inversion of CH4 mole fraction and stable isotope (C-13-CH4) measurements. Emissions were estimated at monthly resolution from 2000 to 2011. A posteriori, the total emission for East Asia increased from 434 to 594Tgyr(-1) between 2000 and 2011, owing largely to the increase in emissions from China, from 394 to 544Tgyr(-1), while emissions in other East Asian countries remained relatively stable. For China, South Korea, and Japan, the total emissions were smaller than the prior estimates (i.e., Emission Database for Global Atmospheric Research 4.2 FT2010 for anthropogenic emissions) by an average of 29%, 20%, and 23%, respectively. For Mongolia, Taiwan, and North Korea, the total emission was less than 2Tgyr(-1) and was not significantly different from the prior. The largest reductions in emissions, compared to the prior, occurred in summer in regions important for rice agriculture suggesting that this source is overestimated in the prior. Furthermore, an analysis of the isotope data suggests that the prior underestimates emissions from landfills and ruminant animals for winter 2010 to spring 2011 (no data available for other times). The inversion also found a lower average emission trend for China, 1.2Tgyr(-1) compared to 2.8Tgyr(-1) in the prior. This trend was not constant, however, and increased significantly after 2005, up to 2.0Tgyr(-1). Overall, the changes in emissions from China explain up to 40% of the increase in global emissions in the 2000s.

Petrenko, VV, Etheridge DM, Weiss RF, Brook EJ, Schaefer H, Severinghaus JP, Smith AM, Lowe D, Hua QA, Riedel K.  2010.  Methane from the East Siberian Arctic Shelf. Science. 329:1146-1147.   10.1126/science.329.5996.1146-b   AbstractWebsite

In their Report “Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf” (5 March, p. 1246), N. Shakhova et al. write that methane (CH4) release resulting from thawing Arctic permafrost “is a likely positive feedback to climate warming.” They add that the release of Arctic CH4 was implied in previous climate shifts as well as in the recently renewed rise in atmospheric CH4. These claims are not supported by all the literature they cite. Their reference 5 (1) presents measurements of emissions only of carbon dioxide, not CH4. Their reference 8 (2), a study we conducted, suggests that a very large (∼50%) increase in atmospheric CH4 concentration associated with an abrupt warming event ∼11,600 years ago was driven mainly by wetlands, without distinguishing between high and low latitudes. Their reference 9 (3) was published in 1993 and is not relevant to the renewed growth of atmospheric CH4 that started in 2007. Their reference 10 (4) does not imply Arctic CH4 releases in this renewed growth, and other recent work (5) also does not support sustained new emissions from the Arctic as the cause.

Penkett, SA, Butler JH, Kurylo MJ, Reeves CE, Rodriguez JM, Singh H, Toohey D, Weiss R.  1995.  Methyl bromide. Scientific assessment of ozone depletion: 1994 (World Meterological Organization, Global Ozone Research and Monitoring Report). ( World Meteorological O, Ed.).:26., Geneva, Switzerland; Nairobi, Kenya; Washington, DC, USA: World Meteorological Organization Abstract
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Chipperfield, MP, Liang Q, Rigby M, Hossaini R, Montzka SA, Dhomse S, Feng WH, Prinn RG, Weiss RF, Harth CM, Salameh PK, Muhle J, O'Doherty S, Young D, Simmonds PG, Krummel PB, Fraser PJ, Steele LP, Happell JD, Rhew RC, Butler J, Yvon-Lewis SA, Hall B, Nance D, Moore F, Miller BR, Elkins J, Harrison JJ, Boone CD, Atlas EL, Mahieu E.  2016.  Model sensitivity studies of the decrease in atmospheric carbon tetrachloride. Atmospheric Chemistry and Physics. 16:15741-15754.   10.5194/acp-16-15741-2016   AbstractWebsite

Carbon tetrachloride (CCl4) is an ozone-depleting substance, which is controlled by the Montreal Protocol and for which the atmospheric abundance is decreasing. However, the current observed rate of this decrease is known to be slower than expected based on reported CCl4 emissions and its estimated overall atmospheric lifetime. Here we use a three-dimensional (3-D) chemical transport model to investigate the impact on its predicted decay of uncertainties in the rates at which CCl4 is removed from the atmosphere by photolysis, by ocean uptake and by degradation in soils. The largest sink is atmospheric photolysis (74% of total), but a reported 10% uncertainty in its combined photolysis cross section and quantum yield has only a modest impact on the modelled rate of CCl4 decay. This is partly due to the limiting effect of the rate of transport of CCl4 from the main tropospheric reservoir to the stratosphere, where photolytic loss occurs. The model suggests large interannual variability in the magnitude of this stratospheric photolysis sink caused by variations in transport. The impact of uncertainty in the minor soil sink (9% of total) is also relatively small. In contrast, the model shows that uncertainty in ocean loss (17% of total) has the largest impact on modelled CCl4 decay due to its sizeable contribution to CCl4 loss and large lifetime uncertainty range (147 to 241 years). With an assumed CCl4 emission rate of 39 Gg year(-1), the reference simulation with the best estimate of loss processes still underestimates the observed CCl4 (overestimates the decay) over the past 2 decades but to a smaller extent than previous studies. Changes to the rate of CCl4 loss processes, in line with known uncertainties, could bring the model into agreement with in situ surface and remote-sensing measurements, as could an increase in emissions to around 47 Gg year(-1). Further progress in constraining the CCl4 budget is partly limited by systematic biases between observational datasets. For example, surface observations from the National Oceanic and Atmospheric Administration (NOAA) network are larger than from the Advanced Global Atmospheric Gases Experiment (AGAGE) network but have shown a steeper decreasing trend over the past 2 decades. These differences imply a difference in emissions which is significant relative to uncertainties in the magnitudes of the CCl4 sinks.

Killworth, PD, Carmack EC, Weiss RF, Matear R.  1996.  Modeling deep-water renewal in Lake Baikal. Limnology and Oceanography. 41:1521-1538. AbstractWebsite

Temperature, dissolved oxygen, nutrients, and chlorofluorocarbon-12 data obtained from Lake Baikal are used to describe deep-water renewal in a deep, temperate-latitude lake. Observations are used to propose the physical mechanism governing convection and to formulate a model of deep ventilation. The key physical mechanism governing deep-water renewal is the so-called thermobaric instability. Because the temperature of maximum density decreases with depth, a lake can become conditionally unstable if the base of the cold mixed layer is displaced to a depth at which its temperature matches the local temperature of maximum density, thereby resulting in sinking plumes. An important consequence of this phenomenon is that deep temperate lakes such as Baikal do not completely mix twice yearly; instead, deep ventilation is episodic. A two-dimensional model of a wind- and buoyancy-driven lake shows many strong mixing events and a fairly realistic seasonal cycle, indicating that the hypothesis is physically realizable. A filling-box model is used to deduce the annually averaged fluxes necessary to produce a steady vertical distribution of tracers as observed. Good fits are obtained to oxygen and chlorofluorocarbon distributions by this model.

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Rhew, RC, Miller BR, Weiss RF.  2000.  Natural methyl bromide and methyl chloride emissions from coastal salt marshes. Nature. 403:292-295.   10.1038/35002043   AbstractWebsite

Atmospheric methyl bromide (CH3Br) and methyl chloride (CH3Cl), compounds that are involved in stratospheric ozone depletion, originate from both natural and anthropogenic sources. Current estimates of CH3Br and CH3Cl emissions from oceanic sources, terrestrial plants and fungi, biomass burning and anthropogenic inputs do not balance their losses owing to oxidation by hydroxyl radicals, oceanic degradation, and consumption in soils, suggesting that additional natural terrestrial sources may be important(1). Here we show that CH3Br and CH3Cl are released to the atmosphere from all vegetation zones of two coastal salt marshes. We see very large fluxes of CH3Br and CH3Cl per unit area: up to 42 and 570 mu mol m(-2) d(-1), respectively. The fluxes show large diurnal, seasonal and spatial variabilities, but there is a strong correlation between the fluxes of CH3Br and those of CH3Cl, with an average molar flux ratio of roughly 1:20. If our measurements are typical of salt marshes globally, they suggest that such ecosystems, even though they constitute less than 0.1% of the global surface area(2), may produce roughly 10% of the total fluxes of atmospheric CH3Br and CH3Cl.

Arnold, T, Harth CM, Mühle J, Manning AJ, Salameh PK, Kim J, Ivy DJ, Steele PL, Petrenko VV, Severinghaus JP, Baggenstos D, Weiss RF.  2013.  Nitrogen trifluoride global emissions estimated from updated atmospheric measurements. Proceedings of the National Academy of Sciences.   10.1073/pnas.1212346110   AbstractWebsite

Nitrogen trifluoride (NF3) has potential to make a growing contribution to the Earth’s radiative budget; however, our understanding of its atmospheric burden and emission rates has been limited. Based on a revision of our previous calibration and using an expanded set of atmospheric measurements together with an atmospheric model and inverse method, we estimate that the global emissions of NF3 in 2011 were 1.18 ± 0.21 Gg⋅y−1, or ∼20 Tg CO2-eq⋅y−1 (carbon dioxide equivalent emissions based on a 100-y global warming potential of 16,600 for NF3). The 2011 global mean tropospheric dry air mole fraction was 0.86 ± 0.04 parts per trillion, resulting from an average emissions growth rate of 0.09 Gg⋅y−2 over the prior decade. In terms of CO2 equivalents, current NF3 emissions represent between 17% and 36% of the emissions of other long-lived fluorinated compounds from electronics manufacture. We also estimate that the emissions benefit of using NF3 over hexafluoroethane (C2F6) in electronics manufacture is significant—emissions of between 53 and 220 Tg CO2-eq⋅y−1 were avoided during 2011. Despite these savings, total NF3 emissions, currently ∼10% of production, are still significantly larger than expected assuming global implementation of ideal industrial practices. As such, there is a continuing need for improvements in NF3 emissions reduction strategies to keep pace with its increasing use and to slow its rising contribution to anthropogenic climate forcing.

Weiss, RF, Muhle J, Salameh PK, Harth CM.  2008.  Nitrogen trifluoride in the global atmosphere. Geophysical Research Letters. 35   10.1029/2008gl035913   AbstractWebsite

Background atmospheric abundances and trends of nitrogen trifluoride (NF(3)), a potent anthropogenic greenhouse gas, have been measured for the first time. The mean global tropospheric concentration of NF(3) has risen quasi-exponentially from about 0.02 ppt (parts-per-trillion, dry air mole fraction) at the beginning of our measured record in 1978, to a July 1, 2008 value of 0.454 ppt, with a rate of increase of 0.053 ppt yr(-1), or about 11% per year, and an interhemispheric gradient that is consistent with these emissions occuring overwhelmingly in the Northern Hemisphere, as expected. This rise rate corresponds to about 620 metric tons of current NF(3) emissions globally per year, or about 16% of the poorly-constrained global NF(3) production estimate of 4,000 metric tons yr(-1). This is a significantly higher percentage than has been estimated by industry, and thus strengthens the case for inventorying NF(3) production and for regulating its emissions. Citation: Weiss, R. F., J. Muhle, P. K., Salameh, and C.M. Harth (2008), Nitrogen trifluoride in the global atmosphere, Geophys. Res. Lett., 35, L208121, doi: 10.1029/2008GL035913.

Weiss, RF.  2002.  Nitrous Oxide. The encyclopedia of global change : environmental change and human society. 2( Goudie AS, Cuff DJ, Eds.).:140-141., Oxford: Oxford University Press Abstract
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Thompson, RL, Chevallier F, Crotwell AM, Dutton G, Langenfelds RL, Prinn RG, Weiss RF, Tohjima Y, Nakazawa T, Krummel PB, Steele LP, Fraser P, O'Doherty S, Ishijima K, Aoki S.  2014.  Nitrous oxide emissions 1999 to 2009 from a global atmospheric inversion. Atmospheric Chemistry and Physics. 14:1801-1817.   10.5194/acp-14-1801-2014   AbstractWebsite

N2O surface fluxes were estimated for 1999 to 2009 using a time-dependent Bayesian inversion technique. Observations were drawn from 5 different networks, incorporating 59 surface sites and a number of ship-based measurement series. To avoid biases in the inverted fluxes, the data were adjusted to a common scale and scale offsets were included in the optimization problem. The fluxes were calculated at the same resolution as the transport model (3.75 degrees longitude x 2.5 degrees latitude) and at monthly time resolution. Over the 11-year period, the global total N2O source varied from 17.5 to 20.1 Tg a(-1) N. Tropical and subtropical land regions were found to consistently have the highest N2O emissions, in particular in South Asia (20 +/- 3% of global total), South America (13 +/- 4 %) and Africa (19 +/- 3 %), while emissions from temperate regions were smaller: Europe (6 +/- 1 %) and North America (7 +/- 2 %). A significant multi-annual trend in N2O emissions (0.045 Tg a(-2) N) from South Asia was found and confirms inventory estimates of this trend. Considerable interannual variability in the global N2O source was observed (0.8 Tg a(-1) N, 1 standard deviation, SD) and was largely driven by variability in tropical and subtropical soil fluxes, in particular in South America (0.3 Tg a(-1) N, 1 SD) and Africa (0.3 Tg a(-1) N, 1 SD). Notable variability was also found for N2O fluxes in the tropical and southern oceans (0.15 and 0.2 Tg a(-1) N, 1 SD, respectively). Interannual variability in the N2O source shows some correlation with the El Nino-Southern Oscillation (ENSO), where El Nino conditions are associated with lower N2O fluxes from soils and from the ocean and vice versa for La Nina conditions.

Weiss, RF, Price BA.  1980.  Nitrous oxide solubility in water and seawater. Marine Chemistry. 8:347-359.   10.1016/0304-4203(80)90024-9   AbstractWebsite

The solubility of nitrous oxide in pure water and seawater has been measured microgasometrically over the range 0–40°C. The data have been corrected for nonideality and are fitted to equations in temperature and salinity of the form used previously to fit the solubilities of other gases. The fitted values have a precision of 0.1% and an estimated accuracy of 0.3%. The nonideal behavior of nitrous oxide—air mixtures is discussed, and the solubility of atmospheric nitrous oxide is presented in parametric form. A similar parametric representation for the solubility of atmospheric carbon dioxide is given in the Appendix.

Landrum, LL, Gammon RH, Feely RA, Murphy PP, Kelly KC, Cosca CE, Weiss RF.  1996.  North Pacific Ocean CO2 disequilibrium for spring through summer, 1985-1989. Journal of Geophysical Research-Oceans. 101:28539-28555.   10.1029/96jc02100   AbstractWebsite

Extensive measurements of CO2 fugacity in the North Pacific surface ocean and overlying atmosphere during the years 1985-1989 are synthesized and interpreted to yield a basin-wide estimate of Delta fCO(2). The observations, taken from February through early September, suggest that the subtropical and subarctic North Pacific is a small sink for atmospheric CO2 (0.07 to 0.2 Gton C (half year)(-1) for the region north of 15 degrees N). Objective analysis techniques are used to estimate uncertainty fields resulting from constructing basin-wide contours of oceanic fCO(2) on the basis of individual cruise transects. The uncertainties are significant and imply that future sampling programs need to recognize that estimating oceanic uptake of anthropogenic CO2 from ship-transect observations of oceanic fCO(2) alone will require very extensive sampling.

Petrenko, VV, Severinghaus JP, Brook EJ, Muhle J, Headly M, Harth CM, Schaefer H, Reeh N, Weiss RF, Lowe D, Smith AM.  2008.  A novel method for obtaining very large ancient air samples from ablating glacial ice for analyses of methane radiocarbon. Journal of Glaciology. 54:233-244.   10.3189/002214308784886135   AbstractWebsite

We present techniques for obtaining large (similar to 100 L STP) samples of ancient air for analysis of (14)C of methane ((14)CH(4)) and other trace constituents. Paleoatmospheric (14)CH(4) measurements should constrain the fossil fraction of past methane budgets, as well as provide a definitive test of methane clathrate involvement in large and rapid methane concentration ([CH(4)]) increases that accompanied rapid warming events during the last deglaciation. Air dating to the Younger Dryas-Preboreal and Oldest Dryas-Bolling abrupt climatic transitions was obtained by melt extraction from old glacial ice outcropping at an ablation margin in West Greenland. The outcropping ice and occluded air were dated using a combination of delta(15)N of N(2), delta(18)O of O(2), delta(18)O(ice) and [CH(4)] measurements. The [CH(4)] blank of the melt extractions was <4 ppb. Measurements of delta(18)O and delta(15)N indicated no significant gas isotopic fractionation from handling. Measured Ar/N(2), CFC-11 and CFC-12 in the samples indicated no significant contamination from ambient air. Ar/N(2), Kr/Ar and Xe/Ar ratios in the samples were used to quantify effects of gas dissolution during the melt extractions and correct the sample [CH(4)]. Corrected [CH(4)] is elevated over expected values by up to 132 ppb for most samples, suggesting some in situ CH(4) production in ice at this site.

Edmond, JM, Stallard RF, Craig H, Craig V, Weiss RF, Coulter GW.  1993.  Nutrient chemistry of the water column of Lake Tanganyika. Limnology and Oceanography. 38:725-738. AbstractWebsite

Lake Tanganyika shows permanent thermal stratification with deep-water temperatures that have been stable over the period of observation (since 1939). The lake is anoxic below approximately 150-m depth. In general the nutrients show Redfield behavior save in the deep waters of the northern basin where large excesses of phosphate and ammonia are present. Bacterial disproportionation of organic material probably plays an important role in producing these excesses. Inorganic desorption from fluvial detritus is also a possible source of excess phosphate in deep waters. The oxic-anoxic boundary at approximately 150 m is a sink for all forms of fixed nitrogen. Thus the nutrient budget of the lake probably involves fixation of nitrogen in the surface layer in addition to substantial inputs from rainfall and runoff, with the phosphate supplied by vertical mixing. Because these processes are in approximate balance under present conditions, the productivity of the lake must be very sensitive to changes in climatic forcing.

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Patra, PK, Krol MC, Montzka SA, Arnold T, Atlas EL, Lintner BR, Stephens BB, Xiang B, Elkins JW, Fraser PJ, Ghosh A, Hintsa EJ, Hurst DF, Ishijima K, Krummel PB, Miller BR, Miyazaki K, Moore FL, Muhle J, O'Doherty S, Prinn RG, Steele LP, Takigawa M, Wang HJ, Weiss RF, Wofsy SC, Young D.  2014.  Observational evidence for interhemispheric hydroxyl-radical parity. Nature. 513:219-+.   10.1038/nature13721   AbstractWebsite

The hydroxyl radical (OH) is a key oxidant involved in the removal of air pollutants and greenhouse gases from the atmosphere(1-3). The ratio of Northern Hemispheric to Southern Hemispheric (NH/SH) OH concentration is important for our understanding of emission estimates of atmospheric species such as nitrogen oxides and methane(4-6). It remains poorly constrained, however, with a range of estimates from 0.85 to 1.4 (refs 4,7-10). Here we determine the NH/SH ratio of OH with the help of methyl chloroform data (a proxy for OH concentrations) and an atmospheric transport model that accurately describes interhemispheric transport and modelled emissions. We find that for the years 2004-2011 the model predicts an annual mean NH-SH gradient of methyl chloroform that is a tight linear function of the modelled NH/SH ratio in annual mean OH. We estimate a NH/SH OH ratio of 0.97 +/- 0.12 during this time period by optimizing global total emissions and mean OH abundance to fit methyl chloroform data from two surface-measurement networks and aircraft campaigns(11-13). Our findings suggest that top-down emission estimates of reactive species such as nitrogen oxides in key emitting countries in the NH that are based on a NH/SH OH ratio larger than 1 may be overestimated.

Greally, BR, Manning AJ, Reimann S, McCulloch A, Huang J, Dunse BL, Simmonds PG, Prinn RG, Fraser PJ, Cunnold DM, O'Doherty S, Porter LW, Stemmler K, Vollmer MK, Lunder CR, Schmidbauer N, Hermansen O, Arduini J, Salameh PK, Krummel PB, Wang RHJ, Folini D, Weiss RF, Maione M, Nickless G, Stordal F, Derwent RG.  2007.  Observations of 1,1-difluoroethane (HFC-152a) at AGAGE and SOGE monitoring stations in 1994-2004 and derived global and regional emission estimates. Journal of Geophysical Research-Atmospheres. 112   10.1029/2006jd007527   AbstractWebsite

[1] Ground-based in situ measurements of 1,1-difluoroethane (HFC-152a, CH3CHF2) which is regulated under the Kyoto Protocol are reported under the auspices of the AGAGE (Advanced Global Atmospheric Gases Experiment) and SOGE (System of Observation of halogenated Greenhouse gases in Europe) programs. Observations of HFC-152a at five locations (four European and one Australian) over a 10 year period were recorded. The annual average growth rate of HFC-152a in the midlatitude Northern Hemisphere has risen from 0.11 ppt/yr to 0.6 ppt/yr from 1994 to 2004. The Southern Hemisphere annual average growth rate has risen from 0.09 ppt/yr to 0.4 ppt/yr from 1998 to 2004. The 2004 average mixing ratio for HFC-152a was 5.0 ppt and 1.8 ppt in the Northern and Southern hemispheres, respectively. The annual cycle observed for this species in both hemispheres is approximately consistent with measured annual cycles at the same locations in other gases which are destroyed by OH. Yearly global emissions of HFC-152a from 1994 to 2004 are derived using the global mean HFC-152a observations and a 12-box 2-D model. The global emission of HFC-152a has risen from 7 Kt/yr to 28 Kt/yr from 1995 to 2004. On the basis of observations of above-baseline elevations in the HFC-152a record and a consumption model, regional emission estimates for Europe and Australia are calculated, indicating accelerating emissions from Europe since 2000. The overall European emission in 2004 ranges from 1.5 to 4.0 Kt/year, 5-15% of global emissions for 1,1-difluoroethane, while the Australian contribution is negligible at 5-10 tonnes/year, < 0.05% of global emissions.

Whitworth, T, Nowlin WD, Pillsbury RD, Moore MI, Weiss RF.  1991.  Observations of the Antarctic Circumpolar Current and deep boundary current in the southwest Atlantic. Journal of Geophysical Research-Oceans. 96:15105-15118.   10.1029/91jc01319   AbstractWebsite

Fourteen-month velocity and temperature records from an array of 14 moorings north and west of the Falkland Plateau and supporting hydrographic and tracer data reveal a narrow boundary current that carries dense Antarctic waters. The current flows west along the northern flank of the Falkland Plateau with mean speeds of more than 10 cm s-1 at 5000 m and more than 30 cm s-1 at 2500 m. The westward flow extends from the bottom to at least 1000 m, but the upper portion of the current is a branch of the Antarctic Circumpolar Current (ACC) following the only deepwater route between the Scotia Sea and the Argentine Basin. Waters colder than 0.2-degrees-C are too cold to be associated with the ACC at Drake Passage and must ultimately derive from the Weddell Sea as part of the deep thermohaline circulation. The westward transport of water colder than 0.2-degrees-C is 8.2 x 10(6) m3 s-1. In the mean the bottom boundary current is similar to that predicted by the Stommel-Arons model, but considerable variability is introduced by the meandering of the overlying ACC. Chlorofluorocarbon data suggest that new Antarctic water from the Georgia Basin enters the Argentine Basin via the deep boundary current, which passes beneath the ACC; some new water is also advected east after being entrained in the ACC. Most of the water in the deep boundary current is recirculated water that has been in residence in the Argentine Basin for some time. Water colder than -0.2-degrees-C is relatively new to the basin and comprises about 2.5 x 10(6) m3 s-1 of the westward flow of the boundary current.

Reimann, S, Elkins JW, Fraser PJ, Hall BD, Kurylo MJ, Mahieu E, Montzka SA, Prinn RG, Rigby M, Simmonds PG, Weiss RF.  2018.  Observing the atmospheric evolution of ozone-depleting substances. Comptes Rendus Geoscience. 350:384-392.   10.1016/j.crte.2018.08.008   AbstractWebsite

The atmospheric observations of ozone-depleting substances (ODSs) have been essential for following their atmospheric response to the production and use restrictions imposed by the Montreal Protocol and its Amendments and Adjustments. ODSs have been used since the first half of the 20th century in industrial and domestic applications. However, their atmospheric growth went unnoticed until the early 1970s, when they were discovered using gas chromatograph-electron capture detection (GC-ECD) instruments. Similar instrumentation formed the basis of global flask and in situ measurements commenced by NOAA and ALE/GAGE/AGAGE in the late 1970s. The combination of these networks, supported by a number of other laboratories, has been essential for following the tropospheric trends of ODSs. Additionally, ground-based remote sensing measurements within NDACC and aircraft-based observation programs have been crucial for measuring the evolution of the ODS abundances over the entire atmosphere. Maintaining these networks at least at their current state is vital for ensuring the on-going verification of the success of the Montreal Protocol. (C) 2018 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.