Flask-sampling network

Tropospheric S - C ratios were obtained from international networks such as the NOAA/CMDL Cooperative Flask Sampling Network (National Oceanic and Atmospheric Administration/Cli-mate Monitoring and Diagnostics Laboratory) in cooperation with INSTAAR (Stable Isotope Laboratory at the Institute of Arctic and Alpine Research), the CSIRO network (Commonwealth Scientific and Industrial Research Organization) or the SIO network (Scripps Institution of Oceanography). Within these networks, tropospheric air samples, collected generally in remote areas, are analyzed for [COy] (all sites) and d C ratios (at selected sites Trolier et fl/., 1996). 

All three estimates of A based on measurements of free tropospheric or canopy air were close to each other (Table 3). Since the spatial representation of the flask-sampling networks is still limited (Tans et al, 1996), the collection of canopy air to deduce A, can be recommended. 

Three-dimensional representation of the latitudinal distribution of atmospheric carbon dioxide in the marine boundary layer. Data from the NOAA CMDL cooperative air sampling network were used. The surface represents data smoothed in time and latitude. The Norwegian and Swedish flask sampling effort at Zeppelin Station is shown in the inset as flask monthly means. (Figure kindly provided by Dr Pieter Tans and Dr Thomas Conway of NOAA (CMDL).)... 

A second top-down method for determining oceanic and terrestrial sinks is based on spatial and temporal variations in concentrations of atmospheric CO2 obtained through a network of flask air samples (Masarie and Tans, 1995 Cooperative Atmospheric Data Integration Project—Carbon Dioxide, 1997). Together with models of atmospheric transport, these variations are used to infer the geographic distribution of sources and sinks of carbon through a technique called inverse modeling. 

Network Synthesis (4) Solid MDI was weighed into a flask and an equivalent amount of polyol added. The mixture was heated to about 40°C to dissolve the MDI. The mixture was then cooled to room temperature and degassed for several minutes under vacuum in order to remove dissolved air. Catalyst was then added and the contents of the flask mixed under vacuum to ensure uniformity and then poured into a mold. All operations were carried out in a dry glove bag to minimize reaction with atmospheric water. The cross-linking process was also carried out in dioxane solution at 70% volume fraction of solids. Polyurethane networks with different crosslink densities were prepared by varying the ratio of difunctional and trifunctional polyols. All samples were extracted with dioxane to remove unreacted and uncrosslinked materialbefore swelling. 

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