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Measurements of trace gases in air trapped in polar ®rn (unconsolidated snow) demonstrate that natural sources of chloro¯uorocarbons, halons, persistent chlorocarbon solvents and sulphur hexa¯uoride to the atmosphere are minimal or non-existent. Atmospheric concentrations of these gases, reconstructed back to the late nineteenth century, are consistent with(More)
Earth's climate is warming as a result of anthropogenic emissions of greenhouse gases, particularly carbon dioxide (CO(2)) from fossil fuel combustion. Anthropogenic emissions of non-CO(2) greenhouse gases, such as methane, nitrous oxide and ozone-depleting substances (largely from sources other than fossil fuels), also contribute significantly to warming.(More)
Surface waters along a cruise track in the East Pacific Ocean were undersaturated in methyl bromide (CH(3)Br) in most areas except for coastal and upwelling regions, with saturation anomalies ranging from + 100 percent in coastal waters to -50 percent in open ocean areas, representing a regionally weighted mean of -16 (-13 to -20) percent. The partial(More)
[1] We simulate the oceanic and atmospheric distribution of methyl iodide (CH 3 I) with a global 3-D model driven by assimilated meteorological observations from the Goddard Earth Observing System of the NASA Data Assimilation Office and coupled to an oceanic mixed layer model. A global compilation of atmospheric and oceanic observations is used to(More)
In this study, we report measurements of CFC-12 (CCl 2 F 2) in firn air and in air extracted from shallow ice cores from three Antarctic sites. The firn air data are consistent with the known atmospheric history of CFC-12. In contrast, some of the ice core samples collected near the firn-ice transition exhibit anomalously high CFC-12 levels. Together, the(More)
[1] Carbonyl sulfide (COS) and other trace gases were measured in firn air collected near South Pole (89.98°S) and from air trapped in ice at Siple Dome, Antarctica (81.65°S). The results, when considered with ambient air data and previous ice core measurements, provide further evidence that atmospheric mixing ratios of COS over Antarctica between 1650 and(More)
[1] Measurements of methyl chloride (CH 3 Cl) in Antarctic polar ice and firn air are used to describe the variability of atmospheric CH 3 Cl during the past 300 years. Firn air results from South Pole and Siple Dome suggest that the atmospheric abundance of CH 3 Cl increased by about 10% in the 50 years prior to 1990. Ice core measurements from Siple Dome(More)
This work describes the in situ synthesis of oligonucleotide arrays on glass surfaces. These arrays are composed of features defined and separated by differential surface tension (surface tension arrays). Specifically, photolithographic methods were used to create a series of spatially addressable, circular features containing an amino-terminated(More)
Atmospheric three-dimensional inverse modeling of regional industrial emissions and global oceanic uptake of carbon tetrachloride, Atmos. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Abstract. Carbon tetrachloride (CCl 4) has substantial strato-spheric ozone depletion potential and(More)