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John E. Mak and Carl A. M. Brenninkmeijer

June '1993)ABSTRACT A methodology for the collection of large ( 1000 L) air samples for isotopic analysis of atmospheric carbonmonoxide is presented. A low-background, high-pressure, high-flow sampling system with a residual backgroundof less than 2 ppbv CO has been built and employed for collection of samples both from the ground and froman aircraft platform. The time required for obtaining a 1000-L sample pressurized to 600 psi was approximately30 min on the ground, and 75 min at 8-km altitude

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Brett F. Thornton, Axel Horst, Daniel Carrizo, Henry Holmstrand, Per Andersson, Patrick M. Crill, and Örjan Gustafsson

purification system is to procure CH 3 Br from the ambient atmosphere in sufficient purity and quantity and without method-induced isotope fractionation so as to allow high-precision Br isotope analysis; this paper describes reaching these goals. A secondary goal is trapping sufficient CH 3 Cl for Cl isotope analysis. Our current analytical method for bromine isotopes [gas chromatography hyphenated with inductively coupled plasma multicollector mass spectrometry (GC-ICP-mcMS)] has a limit of quantification

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Douglas Lowenthal, A. Gannet Hallar, Ian McCubbin, Robert David, Randolph Borys, Peter Blossey, Andreas Muhlbauer, Zhiming Kuang, and Mary Moore

virtual impactor that excludes cloud droplets. Ice water content (IWC) was derived from the wind speed and the diameter of the tubes. Snow samples were transferred to a storage bag and stored in a freezer. After the study, aliquots of cloud and snow water samples were sent to the Institute of Arctic and Alpine Research (INSTAAR) in Boulder, Colorado, for analysis of stable isotopes of water ( Lowenthal et al. 2011 ). A weather station measured 5-min average temperature, relative humidity (RH), and

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Joshua Rambo, Chun-Ta Lai, James Farlin, Matt Schroeder, and Ken Bible

1. Introduction Isotope-enabled general circulation models (GCMs) are a unique tool to compare the stable isotope ratios in precipitation ( δ 18 O and δ 2 H) in contemporary and paleoclimatic conditions ( Joussaume et al. 1984 ). GCMs are able to simulate regional distributions of atmospheric water vapor and its stable isotope ratios ( δ 18 O v and δ 2 H v ), but these model simulations are difficult to validate, and rarely do so, because of the scarcity of direct and continuous δ 18 O v

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Cyrille N. Flamant, Geary K. Schwemmer, C. Laurence Korb, Keith D. Evans, and Stephen P. Palm

conventional analysis, partly because of mesoscale variability in both the atmosphere and ocean, which is generally observed to be very large. Bond and Feagle (1985) suggested that atmospheric dynamics take place on scales that are not practically resolvable with conventional methods. Better determination of the winds, stress, sea surface temperature, and frontal location is essential for progress in these mesoscale modeling efforts. Nuss and Brown (1987) have shown that the primary limitation on the

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Paul A. Dodd, Martin R. Price, Karen J. Heywood, and Miles Pebody

rotary valve were then flushed with water from the carboy. Finally, a second set of salinity and tracer samples was taken from the carboy to monitor any change in prime water properties during the procedure. After the recovery of Autosub, sample bags were detached from the AquaLAB and each sample was divided between one 150-mL bottle for salinity measurement, two 50-mL bottles for oxygen isotope analysis, and one 5-mL bottle for barium analysis. Because three sets of samples were required from this

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C. A. M. Brenninkmeijer, P. J. Crutzen, H. Fischer, H. Güsten, W. Hans, G. Heinrich, J. Heintzenberg, M. Hermann, T. Immelmann, D. Kersting, M. Maiss, M. Nolle, A. Pitscheider, H. Pohlkamp, D. Scharffe, K. Specht, and A. Wiedensohler

sensor as well as a conventional ozone monitor, a gas chromatograph for CO analysis, two condensation nuclei counters for submicron particles larger than 5 and 12 nm, and the 12 canister large-capacity whole air sampler for postflight concentration and isotopic measurement in the laboratory. With the exception of the fast-response ozone sensor and the whole air sampler, all apparatus are commercially available laboratory instruments that have undergone varying degrees of modifications and

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C. A. M. Brenninkmeijep and P. A. Roberts

special attention to the problem ofcollecting air in the lower stratosphere for the isotopic analysis of carbon monoxide.1. Introduction Isotopic analysis is being increasingly used for betterunderstanding the cycles of atmospheric trace gases,and in several cases rather unique information is beingobtained. For instance the ~4C activity of atmosphericCH4, when combined with its ~3C/~2C ratio is a goodestimator of the biogenic fraction of this greenhousegas (Lowe et al. 1988; Wahlen et al. 1989). In

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Xuhui Lee, Steve Sargent, Ronald Smith, and Bert Tanner

are limited to brief campaigns and discrete sampling. The only exception is Jacob and Sonntag (1991) who measured water vapor isotopes on a nearly continuous basis for over 8 yr, but with a rather coarse time resolution of 24–48 h. Previous measurement of water vapor isotopes, except for the two studies noted below, usually involves two steps—collection and analysis—both of which are labor intensive. First, water vapor is collected via bags and subsequently condensed to the liquid form ( Moreira

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Rosario Q. Iannone, Daniele Romanini, Samir Kassi, Harro A. J. Meijer, and Erik R. Th Kerstel

laboratory-based isotope analysis by IRMS (or a laser-based technique). For tropospheric and ecological measurements, such an approach has been used by Helliker et al. (2002) and West et al. (2006) , respectively. Franz and Röckmann (2004) have shown that this approach can be successful, if executed with extreme care, even for studies at very low water mixing ratio, such as encountered high in the troposphere and in the lower stratosphere. They modified a continuous-flow IRMS system to be able to

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