The determination of the global average OH concentration using a deuteroethane tracer

It is proposed to measure the decreasing global concentration of an OH reactive isotopic tracer, G sub 2 D sub 6, after its introduction into the troposphere in a manner to facilitate uniform global mixing. Analyses at the level of 2 x 10 to the -19th power fraction, corresponding to one kg uniformly distributed globally, should be possible by a combination of cryogenic absorption techniques to separate ethane from air and high sensitivity isotopic analysis of ethane by mass spectrometry. Aliquots of C sub 2 D sub 6 totaling one kg would be introduced to numerous southern and northern latitudes over a 10 day period in order to achieve a uniform global concentration within 3 to 6 months by the normal atmospheric circulation. Then samples of air of 1000 l (STP) would be collected periodically at a tropical and temperate zone location in each hemisphere and spiked with a known amount of another isotopic species of ethane, C-13 sub 2 H sub 6, at the level of 10 to the -11th power mole fraction. After separation of the ethanes from air, the absolute concentration of C sub 2 D sub 6 would be analyzed using the Argonne 100-inch radius mass spectrometer

Putting Science to Work in Developing a Climate Policy

The National Academy of Sciences is an honorific society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. This Viewpoint explores the interconnection between scientific research and policy making in developing a climate policy

Highlights: Spring Council Meeting

Council members present at the May 24, 1981, meeting were Keiiti Aki, Steven Burges (for Jim Wallis), Peter S. Eagleson, E. R. Engdahl, Charles E. Helsley, James R. Heirtzler, Carl Kisslinger, Leslie H. Meredith, Chris N. K. Mooers, Norman F. Ness, Marcia M. Neugebauer, James J. O'Brien, Richard Rapp, Carl Sagan, James C. Savage, Joseph V. Smith, Fred Spilhaus, Donald L. Turcotte, James A. Van Allen, J. Tuzo Wilson, and Jay Winston (for Elmar R. Reiter until his arrival at 6:50 P.M.). David Strangway, representing the Canadian Geophysical Union, and Peter Steinhauser, representing the European Geophysical Society, were special observers at the meeting. Council meetings are open, and a number of section secretaries, committee chairmen, journal editors, and other members attended. The following major actions were adopted by the Council: The experiment of publishing oceanography and lower‐atmosphere papers in JGR Green issues alternate to those containing upper‐atmosphere papers will be continued through 1982. From preliminary indications the experiment seems to be working, but a full year of data, including a renewal cycle, is needed to assess the success of the experiment. Final decision will be made prior to the 1983 dues notices

Analysis of sources and sinks of atmospheric nitrous oxide (N 2

Here I use a simple model to place constraints on the relative sizes of N2O sources in the northern and southern hemispheres (NH and SH). Using measurements of the rate of temporal increase of atmospheric nitrous oxide (N2O) concentrations and observations of their cross-equator differences, I calculate the total sources of N2O for the (NH and SH). The NH source ΦN must exceed the SH source ΦS; their ratio R = (ΦN/ΦS) is between 1.7 and 2.4 for the case where the NH concentration is 1 ppb higher than that in the SH. When the NH concentration is 0.75 ppb higher, R is between 1.5 and 1.9. -from Autho

Haloe Antarctic observations in the spring of 1991

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95167/1/grl6630.pd

Highlights: Spring Council Meeting

Council members present at the May 24, 1981, meeting were Keiiti Aki, Steven Burges (for Jim Wallis), Peter S. Eagleson, E. R. Engdahl, Charles E. Helsley, James R. Heirtzler, Carl Kisslinger, Leslie H. Meredith, Chris N. K. Mooers, Norman F. Ness, Marcia M. Neugebauer, James J. O'Brien, Richard Rapp, Carl Sagan, James C. Savage, Joseph V. Smith, Fred Spilhaus, Donald L. Turcotte, James A. Van Allen, J. Tuzo Wilson, and Jay Winston (for Elmar R. Reiter until his arrival at 6:50 P.M.). David Strangway, representing the Canadian Geophysical Union, and Peter Steinhauser, representing the European Geophysical Society, were special observers at the meeting. Council meetings are open, and a number of section secretaries, committee chairmen, journal editors, and other members attended. The following major actions were adopted by the Council: The experiment of publishing oceanography and lower‐atmosphere papers in JGR Green issues alternate to those containing upper‐atmosphere papers will be continued through 1982. From preliminary indications the experiment seems to be working, but a full year of data, including a renewal cycle, is needed to assess the success of the experiment. Final decision will be made prior to the 1983 dues notices

Nanometer Scale Dielectric Fluctuations at the Glass Transition

Using non-contact scanning probe microscopy (SPM) techniques, dielectric properties were studied on 50 nanometer length scales in poly-vinyl-acetate (PVAc) films in the vicinity of the glass transition. Low frequency (1/f) noise observed in the measurements, was shown to arise from thermal fluctuations of the electric polarization. Anomalous variations observed in the noise spectrum provide direct evidence for cooperative nano-regions with heterogeneous kinetics. The cooperative length scale was determined. Heterogeneity was long-lived only well below the glass transition for faster than average processes.Comment: 4 pages, 4 embedded PS figures, RevTeX - To appear in Phys. Rev. Let