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Weiss, RF, Price BA.  1989.  Dead Sea gas solubilities. Earth and Planetary Science Letters. 92:7-10.   10.1016/0012-821x(89)90016-2   AbstractWebsite

The solubilities of helium and argon have been measured in Dead Sea brine. A simple model is presented whereby the solubilities of these and other gases in Dead Sea water as functions of temperature and salinity may be closely approximated from existing equations for the solubilities of these gases in pure water and seawater. The salting out per unit mass of Dead Sea salt exceeds that of sea salt by about 9%. The Bunsen solubility coefficients of a number of selected gases in the Dead Sea are about 15–25% of their values in pure water. Parametric equations are given for calculating the equilibrium concentrations of dissolved atmospheric gases in the Dead Sea.

Fine, RA, Smethie WM, Bullister JL, Rhein M, Min DH, Warner MJ, Poisson A, Weiss RF.  2008.  Decadal ventilation and mixing of Indian Ocean waters. Deep-Sea Research Part I-Oceanographic Research Papers. 55:20-37.   10.1016/j.dsr.2007.10.002   AbstractWebsite

Chlorofluorocarbon (CFC) and hydrographic data from the World Ocean Circulation Experiment (WOCE) Indian Ocean expedition are used to evaluate contributions to decadal ventilation of water masses. At a given density, CFC-derived ages increase and concentrations decrease from the south to north, with lowest concentrations and oldest ages in Bay of Bengal. Average ages for thermocline water are 0-40 years, and for intermediate water they are less than 10 years to more than 40 years. As compared with the marginal seas or throughflow, the most significant source of CFCs for the Indian Ocean south of 12 degrees N is the Southern Hemisphere. A simple calculation is used to show this is the case even at intermediate levels due to differences in gas solubilities and mixing of Antarctic Intermediate Water and Red Sea Water. Bottom water in the Australia-Antarctic Basin is higher in CFC concentrations than that to the west in the Enderby Basin, due to the shorter distance of this water to the Adelie Land coast and Ross Sea sources. However, by 40 degrees S, CFC concentrations in the bottom water of the Crozet Basin originating from the Weddell Sea are similar to those in the South Australia Basin. Independent observations, which show that bottom water undergoes elevated mixing between the Australia-Antarctic Basin and before entering the subtropics, are consistent with high CFC dilutions (3-14-fold) and a substantial concentration decrease (factor of 5) south to north of the Southeast Indian Ridge. CFC-bearing bottom waters with ages 30 years or more are transported into the subtropical South Indian Ocean by three western boundary currents, and highest concentrations are observed in the westernmost current. During WOCE, CFC-bearing bottom water reaches to about 30 degrees S in the Perth Basin, and to 20 degrees S in the Mascarene Basin. Comparing subtropical bottom water-CFC concentrations with those of the South Pacific and Atlantic oceans, at comparable latitudes, Indian Ocean bottom water-CFC concentrations are lower, consistent with its high dissipation rates from tidal mixing and current fluctuations as shown elsewhere. Thus, the generally high dilutions and low CFC concentrations in bottom water of the Indian Ocean are due to distance to the water mass source regions and the relative effectiveness of mixing. While it is not surprising that at thermocline, intermediate, and bottom levels, the significant ventilation sources on decadal time scales are all from the south, the CFCs show how local sources and mixing within the ocean affect the ventilation. (c) 2007 Elsevier Ltd. All rights reserved.

Severinghaus, JP, Albert MR, Courville ZR, Fahnestock MA, Kawamura K, Montzka SA, Muhle J, Scambos TA, Shields E, Shuman CA, Suwa M, Tans P, Weiss RF.  2010.  Deep air convection in the firn at a zero-accumulation site, central Antarctica. Earth and Planetary Science Letters. 293:359-367.   10.1016/j.epsl.2010.03.003   AbstractWebsite

Ice cores provide unique archives of past atmospheres and climate, but interpretation of trapped-gas records and their climatic significance has been hampered by a poor knowledge of the prevalence of air convection in the firn layer on top of polar ice sheets. In particular, the phasing of greenhouse gases and climate from ice cores has been obscured by a discrepancy between empirical and model-based estimates of the age difference between trapped gases and enclosing ice, which may be due to air convection. Here we show that deep air convection (>23 m) occurs at a windy, near-zero-accumulation rate site in central Antarctica known informally as the Megadunes site (80.77914 degrees S, 124.48796 degrees E). Deep convection is evident in depth profiles of air withdrawn from the firn layer, in the observed pattern of the nitrogen isotope ratio (15)N/(14)N, the argon isotope ratio (40)Ar/(36)Ar, and in the mixing ratios of the anthropogenic halocarbons methyl chloroform (CH(3)CCl(3)) and HFC-134a (CH(2)FCF(3)). Transport parameters (diffusivities) were inferred and air was dated using measured carbon dioxide (CO(2)) and methane (CH(4)) mixing ratios, by comparing with the Law Dome atmospheric record, which shows that these are the oldest firn air samples ever recovered (CO(2) mean age = 1863 AD). The low accumulation rate and the consequent intense metamorphism of the firn (due to prolonged exposure to seasonal temperature cycling) likely contribute to deep air convection via large grain size and vertical cracks that act as conduits for vigorous air motion. The Megadunes site provides a possible modern analog for the glacial conditions in the Vostok, Dome Fuji, and Dome C ice core records and a possible explanation for lower-than-expected (15)N/(14)N ratios in trapped air bubbles at these times. A general conclusion is that very low accumulation rate causes deep air convection via its effect on firn structural characteristics. (C) 2010 Elsevier B.V. All rights reserved.

Weiss, RF, Carmack EC, Koropalov VM.  1991.  Deep-water renewal and biological production in Lake Baikal. Nature. 349:665-669.   10.1038/349665a0   AbstractWebsite

The physics of mixing in deep temperate lakes is strongly constrained by the existence of a temperature of maximum density for fresh water, and by the pressure dependence of that temperature. The world's deepest lake is well suited to the study of such deep-water renewal processes, and also to the determination of the rate of renewal using time-dependent chemical tracers. The mean rates of biological recycling of oxygen, carbon and nutrients for the entire lake can then also be determined.

Vollmer, MK, Weiss RF, Schlosser P, Williams RT.  2002.  Deep-water renewal in Lake Issyk-Kul. Geophysical Research Letters. 29   10.1029/2002gl014763   AbstractWebsite

[1] The deep-water renewal rates of Lake Issyk-Kul are studied using the time-dependent anthropogenically produced tracers sulfur hexafluoride (SF6), chlorofluorocarbons (CFCs) and tritium-helium-3. SF6 and the CFCs are used to calibrate a mixing model from which the vertical age distribution is calculated and found to be comparable to the SF6 apparent ages. Based on this model, the mean age of the water below 100 m depth is 6.1 yrs. The mean oxygen consumption rate for the same depth range is 6.4 m mol kg(-1) yr(-1) and the mean remineralization rates for nitrate, phosphate and silicate are 0.53, 0.003 and 0.67 m mol kg(-1) yr(-1), respectively.

Vollmer, MK, Bootsma HA, Hecky RE, Patterson G, Halfman JD, Edmond JM, Eccles DH, Weiss RF.  2005.  Deep-water warming trend in Lake Malawi, East Africa. Limnology and Oceanography. 50:727-732. AbstractWebsite

We use historic water temperature measurements to define a deep-water warming trend in Lake Malawi, East Africa. Over the past six decades, the temperature of the deep water below 300 m has increased by similar to 0.7 degrees C. The warming trend is due mainly to the reduction of cold-water deep convection over this period, which is associated with milder winters in the region. Despite deep-water warming, density stratification was maintained at depths below 100 in. The observed warming trend was interrupted at least twice by abyssal cooling events that were associated with the wettest years on record. We propose that rainfall and cool river inflow are critical factors that control thermal structure and the rate of deep-water recharge in this deep, tropical lake.

Liang, Q, Chipperfield MP, Fleming EL, Abraham LN, Braesicke P, Burkholder JB, Daniel JS, Dhomse S, Fraser PJ, Hardiman SC, Jackman CH, Kinnison DE, Krummel PB, Montzka SA, Morgenstern O, McCulloch A, Mühle J, Newman PA, Orkin VL, Pitari G, Prinn RG, Rigby M, Rozanov E, Stenke A, Tummon F, Velders GJM, Visioni D, Weiss RF.  2017.  Deriving Global OH Abundance and Atmospheric Lifetimes for Long-Lived Gases: A Search for CH3CCl3 Alternatives. Journal of Geophysical Research: Atmospheres. 122:11,914-11,933.   10.1002/2017JD026926   Abstract

An accurate estimate of global hydroxyl radical (OH) abundance is important for projections of air quality, climate, and stratospheric ozone recovery. As the atmospheric mixing ratios of methyl chloroform (CH3CCl3) (MCF), the commonly used OH reference gas, approaches zero, it is important to find alternative approaches to infer atmospheric OH abundance and variability. The lack of global bottom-up emission inventories is the primary obstacle in choosing a MCF alternative. We illustrate that global emissions of long-lived trace gases can be inferred from their observed mixing ratio differences between the Northern Hemisphere (NH) and Southern Hemisphere (SH), given realistic estimates of their NH-SH exchange time, the emission partitioning between the two hemispheres, and the NH versus SH OH abundance ratio. Using the observed long-term trend and emissions derived from the measured hemispheric gradient, the combination of HFC-32 (CH2F2), HFC-134a (CH2FCF3, HFC-152a (CH3CHF2), and HCFC-22 (CHClF2), instead of a single gas, will be useful as a MCF alternative to infer global and hemispheric OH abundance and trace gas lifetimes. The primary assumption on which this multispecies approach relies is that the OH lifetimes can be estimated by scaling the thermal reaction rates of a reference gas at 272 K on global and hemispheric scales. Thus, the derived hemispheric and global OH estimates are forced to reconcile the observed trends and gradient for all four compounds simultaneously. However, currently, observations of these gases from the surface networks do not provide more accurate OH abundance estimate than that from MCF.

Welp, LR, Keeling RF, Weiss RF, Paplawsky W, Heckman S.  2013.  Design and performance of a Nafion dryer for continuous operation at CO2 and CH4 air monitoring sites. Atmos. Meas. Tech.. 6:1217-1226.: Copernicus Publications   10.5194/amt-6-1217-2013   AbstractWebsite

In preparation for routine deployment in a network of greenhouse gas monitoring stations, we have designed and tested a simple method for drying ambient air to near or below 0.2% (2000 ppm) mole fraction H2O using a Nafion dryer. The inlet system was designed for use with cavity ring-down spectrometer (CRDS) analyzers such as the Picarro model G2301 that measure H2O in addition to their principal analytes, in this case CO2 and CH4. These analyzers report dry-gas mixing ratios without drying the sample by measuring H2O mixing ratio at the same frequency as the main analytes, and then correcting for the dilution and peak broadening effects of H2O on the mixing ratios of the other analytes measured in moist air. However, it is difficult to accurately validate the water vapor correction in the field. By substantially lowering the amount of H2O in the sample, uncertainties in the applied water vapor corrections can be reduced by an order of magnitude or more, thus eliminating the need to determine instrument-specific water vapor correction coefficients and to verify the stability over time. Our Nafion drying inlet system takes advantage of the extra capacity of the analyzer pump to redirect 30% of the dry gas exiting the Nafion to the outer shell side of the dryer and has no consumables. We tested the Nafion dryer against a cryotrap (−97 °C) method for removing H2O and found that in wet-air tests, the Nafion reduces the CO2 dry-gas mixing ratios of the sample gas by as much as 0.1 ± 0.01 ppm due to leakage across the membrane. The effect on CH4 was smaller and varied within ± 0.2 ppb, with an approximate uncertainty of 0.1 ppb. The Nafion-induced CO2 bias is partially offset by sending the dry reference gases through the Nafion dryer as well. The residual bias due to the impact of moisture differences between sample and reference gas on the permeation through the Nafion was approximately −0.05 ppm for CO2 and varied within ± 0.2 ppb for CH4. The uncertainty of this partial drying method is within the WMO compatibility guidelines for the Northern Hemisphere, 0.1 ppm for CO2 and 2 ppb for CH4, and is comparable to experimentally determining water vapor corrections for each instrument but less subject to concerns of possible drift in these corrections.

Lucas, DD, Yver Kwok C, Cameron-Smith P, Graven H, Bergmann D, Guilderson TP, Weiss R, Keeling R.  2015.  Designing optimal greenhouse gas observing networks that consider performance and cost. Geosci. Instrum. Method. Data Syst.. 4:121-137.: Copernicus Publications   10.5194/gi-4-121-2015   AbstractWebsite
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Bullister, JL, Weiss RF.  1988.  Determination of CCl3F and CCl2F2 in seawater and air. Deep-Sea Research Part a-Oceanographic Research Papers. 35:839-853.   10.1016/0198-0149(88)90033-7   AbstractWebsite

An improved analytical technique has been developed for the rapid and accurate shipboard measurement of two anthropogenically produced chlorofluorocarbons (CFCs), CCl3F (F-11) and CCl2F2 (F-12) in air and seawater. Gas samples (dry air or standard) are injected into a stream of purified gas and then concentrated in a low temperature trap. Seawater samples collected in oceanographic Niskin bottles are transferred into glass syringes for storage until analysis. An aliquot of approximately 30 cm3 of seawater is introduced into a glass stripping chamber where the dissolved gases are purged with purified gas, and the evolved CFCs are concentrated in the same cold trap. The trap is subsequently isolated and heated, and the CFCs are automatically transferred by a stream of carrier gas into a precolumn and then a chromatographic separating column. The CCl3F and CCl2F2 peaks are detected by an electron capture detector (ECD) and their areas are integrated digitally. CFC amounts are calculated using fitted calibration curves, generated by injection of various multiple aliquots of gas standard containing known concentrations of CFCs. Preliminary concentration values for these compounds are printed at the completion of each analysis. Total analysis time for air and water samples is < 10 min, allowing detailed vertical profiles of the concentrations of these compounds in the water column and concentrations in the overlying atmosphere to be determined within a few hours of the completion of a hydrographic station. Typical relative standard deviations for analyses of CCl3F and CCl2F2 in near-surface seawater containing equilibrium levels of these compounds are approximately 1%. Limits of detection for both compounds in 30 cm3 seawater samples are about 0.005 × 10−12 mol kg−1.

Weiss, RF, Keeling CD, Craig H.  1981.  The determination of tropospheric nitrous oxide. Journal of Geophysical Research-Oceans and Atmospheres. 86:7197-7202.   10.1029/JC086iC08p07197   AbstractWebsite

A two-step technique, in which the N2O/CO2 ratio is measured by ultrasonic phase-shift gas chromatography and the dry air CO2 concentration is measured by nondispersive infrared analysis, has been developed for the determination of the mole fraction of nitrous oxide in dry air. The N2O concentration is given by the product of these two independent measurements and has a precision (±1 standard deviation) ranging between 0.3 and 0.5%. The absence of systematic errors has been verified by extensive standard intercomparisons and by independent cross checks of the sample extraction procedures. The results of extensive measurements by this technique, reported in a companion paper, fix the mean tropospheric dry air mole fraction of nitrous oxide in the northern hemisphere as of January 1, 1978 at 300.2±0.6 parts per billion, including systematic uncertainties.

Weiss, RF.  1981.  Determinations of carbon dioxide and methane by dual catalyst flame ionization chromatography and nitrous oxide by electron capture chromatography. Journal of Chromatographic Science. 19:611-616.   10.1093/chromsci/19.12.611   AbstractWebsite

An automated gas chromatographic (GC) system has been developed for the measurement of carbon dioxide, methane, and nitrous oxide in air and other gases. Carbon dioxide is measured by a flame ionization detector (FID) after conversion to methane in pure hydrogen carrier gas, using palladium and nickel dual catalysts which permit direct on-line injection of oxygen-containing samples. The detector measures methane in the same sample, although the system has not been optimized for this gas. Nitrous oxide is measured in a separate aliquot of the sample using a hot electron capture datector (ECD) and argon-methane carrier gas. Typical relative standard deviations of the calculated results are 0.04% for carbon dioxide, 0.4% for methane, and 0.3% for nitrous oxide.

Weiss, RF.  1969.  Dissolved argon, nitrogen and total carbonate in the Red Sea brines. Hot brines and recent heavy metal deposits in the Red Sea; a geochemical and geophysical account. ( Degens ET, Ross DA, Eds.).:254-260., New York: Springer-Verlag Abstract
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Craig, H, Weiss RF.  1971.  Dissolved gas saturation anomalies and excess helium in the ocean. Earth and Planetary Science Letters. 10:289-296.   10.1016/0012-821x(71)90033-1   AbstractWebsite

New solubility measurements have been made for helium and neon in seawater; the results (published elsewhere) show that neon is actually supersaturated in the ocean, rather than generally undersaturated as indicated by previous data. The pattern of He-Ne-Ar saturation anomalies, based on the new solubility data, shows the presence of an injected “atmospheric component” in Atlantic surface and deep waters and in Pacific deep waters, ranging from 0.5 to 1 ml of air (STP)/kg seawater. Nitrogen-argon relationships in the deep Pacific are also consistent with this effect. In addition to T and P, a third parameter is thus required for the study of saturation anomalies. The magnitude of the injected air fraction accounts for all of the “excess He” in Atlantic Deep Water and about 60% of the excess in the Pacific. The non-atmospheric excess He in the Pacific corresponds to an anomaly of 3%, presumably radiogenic and primordial helium.

Craig, H, Weiss RF, Clarke WB.  1967.  Dissolved gases in Equatorial and South Pacific Ocean. Journal of Geophysical Research. 72:6165-&.   10.1029/JZ072i024p06165   AbstractWebsite

The nitrogen, oxygen, and argon in Pacific samples from two expeditions have been measured by gas chromatography, and the neon and helium by mass spectrometry. Nitrogen is systematically about 2% supersaturated and argon about 1.5% undersaturated, relative to the solubility data of Douglas for a moisture saturated atmosphere at 1013-mb total pressure. N2/Ar ratios are in precise agreement with the solubility ratios of Benson and Parker. The range and covariance of N2 and Ar variations are consistent with atmospheric pressure variations over the sea. Oxygen values are systematically higher than the ‘classical’ Winkler values by 3.7%. No evidence was found for the large supersaturation of argon reported by Bieri, Koide, and Goldberg in 1966 and the Ar-T-S relationships are inconsistent with their vertical mixing model. Small increases in a saturation anomaly are core properties of water types formed by subsurface mixing and are associated with T-S slope changes; these effects were found in Antarctic and North Pacific Intermediate water. An upper limit of 8.7% excess helium was found at a depth of 1000 meters at 33°S latitude.

Mensch, M, Bayer R, Bullister JL, Schlosser P, Weiss RF.  1996.  The Distribution of Tritium and CFCs in the Weddell Sea during the mid-1980s. Progress in Oceanography. 38:377-415.   10.1016/s0079-6611(97)00007-4   AbstractWebsite

Transient tracer data (tritium, CFC11 and CFC12) from the southern, central and northwestern Weddell Sea collected during Polarstern cruises ANT III-3, ANT V-2/3/4 and during Andenes cruise NARE 85 are presented and discussed in the context of hydrographic observations. A kinematic, time-dependent, multi-box model is used to estimate mean residence times and formation rates of several water masses observed in the Weddell Sea. Ice Shelf Water is marked by higher tritium and lower CFC concentrations compared to surface waters. The tracer signature of Ice Shelf Water can only be explained by assuming that its source water mass, Western Shelf Water, has characteristics different from those of surface waters. Using the transient nature of tritium and the CFCs, the mean residence time of Western Shelf Water on the shelf is estimated to be approximately 5 years. Ice Shelf Water is renewed on a time scale of about 14 years from Western Shelf Water by interaction of this water mass with glacial ice underneath the FilchnerRonne Ice shelf. The Ice Shelf Water signature can be traced across the sill of the Filchner Depression and down the continental slope of the southern Weddell Sea. On the continental slope, new Weddell Sea Bottom Water is formed by entrainment of Weddell Deep Water and Weddell Sea Deep Water into the Ice Shelf Water plume. In the northwestern Weddell Sea, new Weddell Sea Bottom Water is observed in two narrow, deep boundary currents flowing along the base of the continental slope. Classically defined Weddeil Sea Bottom Water (theta <= 0.7 degrees C) and Weddell Sea Deep Water (-0.7 degrees C <= theta <= 0 degrees C) are ventilated from the deeper of these boundary currents by lateral spreading and mixing. Model-based estimates yield a total formation rate of 3.5Sv for new Weddell Sea Bottom Water (theta = -1.0 degrees C) and a formation rate of at least 11Sv for Antarctic Bottom Water (theta = -0.5 degrees C). (C) 1997 Elsevier Science Ltd