Other
Scientific paper
Dec 2002
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002agufm.a22b0114r&link_type=abstract
American Geophysical Union, Fall Meeting 2002, abstract #A22B-0114
Other
0305 Aerosols And Particles (0345, 4801), 0343 Planetary Atmospheres (5405, 5407, 5409, 5704, 5705, 5707), 6020 Ice
Scientific paper
Much attention is given to heterogeneous processing on the surface of water-ice aerosols. Less attention is given to how gases can be trapped in the pores of condensing aerosols and thereby be transported to Earth or other regions of the atmosphere. The ability of water-ice to trap, transport, and release volatiles is of particular interest to planetary scientists, who examine the way icy bodies such as comets transport volatiles throughout the solar system. Ice also is a well-known scavenger in the troposphere. Indeed, long-term records of atmospheric CO2 and CH4 are reconstructed from ice core samples formed by gases trapped in fallen snow and ice centuries ago. The amount of volatile that can be trapped in a condensing ice particle depends on factors such as ice porosity, temperature, concentration, uptake coefficients, and condensation rates. A complicating factor is the state of the volatile, whether it is a free molecule or is already trapped in a liquid or solid aerosol. In this work, we examine several of these factors by studying the entrapment of CO2 in a condensing water-ice film under low temperature (90-145 K) and low pressure (10-4-10-7 Torr) conditions. Water vapor enters a high-vacuum chamber through a precision leak valve and is codeposited on a temperature-controlled Al substrate with CO2. CO2 enters the chamber either as a pre-mixed gas with the water vapor or through a separate leak valve. A typical ice film is deposited at 1 nm/s and is 360 nm thick. Following codeposition, the film is annealed (1 K/min) until the ice sublimes. The phase of the film (amorphous or crystalline) is monitored using grazing-angle FTIR-Reflection Absorption Spectroscopy. A calibrated quadrupole mass spectrometer measures the relative amounts of CO2 and H2O. Quantitative results will be presented describing the amount of CO2 trapped in ice as a function of deposition temperature (90, 105, 125, and 145 K), ice phase (amorphous or crystalline), the source of CO2 (separate or co-mixed with water), and the amount of CO2 present during film growth. These results, together with what is already understood about the structure and porosity of amorphous and crystalline ice, will increase our understanding of how volatiles are trapped in water-ice aerosols.
Conley S.
Raymond B.
Robinson Mark S.
No associations
LandOfFree
Trapping and Release of CO2 in Amorphous and Crystalline Water-ice Films does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Trapping and Release of CO2 in Amorphous and Crystalline Water-ice Films, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Trapping and Release of CO2 in Amorphous and Crystalline Water-ice Films will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1891714