عنوان
پدید آورنده
موضوع
رده
کتابخانه
محل استقرار
NATIONAL BIBLIOGRAPHY NUMBER
Number
TLpq2386253686
LANGUAGE OF THE ITEM
.Language of Text, Soundtrack etc
انگلیسی
TITLE AND STATEMENT OF RESPONSIBILITY
Title Proper
A Study of in situ Cosmogenic 14C and Paleoatmospheric 14CH4 from Accumulating Ice at Summit, Greenland
General Material Designation
[Thesis]
First Statement of Responsibility
Hmiel, Benjamin
Subsequent Statement of Responsibility
Petrenko, Vasilii V
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
University of Rochester
Date of Publication, Distribution, etc.
2020
PHYSICAL DESCRIPTION
Specific Material Designation and Extent of Item
294
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
Ph.D.
Body granting the degree
University of Rochester
Text preceding or following the note
2020
SUMMARY OR ABSTRACT
Text of Note
This body of work expands the understanding of in situ cosmogenic 14C production and retention in the upper layer of accumulating ice sheets and presents new measurements of 14CH4 that improve our understanding of the fossil component of the CH4 budget. Samples were collected at Summit, Greenland from the firn air open porosity, the firn matrix and from ice below the depth of bubble closure. Large volume (~100L STP) air samples requiring ~1000kg ice/sample were collected for measurements of 14CH4 and 14CO via on site melt-extraction. Air for 14CO2 analysis was extracted via sublimation of ~1 kg ice samples using a new technique developed as part of this thesis. A model of firn gas transport and in situ cosmogenic 14C production was used to interpret the 14CO results, finding that only ~0.5% of in situ cosmogenic 14C produced in the firn is retained by the accumulating ice crystal lattice. Further, production rates of 14C in ice from deeply-penetrating muons are found to be overestimated by a factor of 3-4. The in situ cosmogenic 14CO2 component in accumulating ice is demonstrated be smaller in magnitude than the combined uncertainty from measurement and model characterization of paleoatmospheric 14CO2 bubble trapping.
TOPICAL NAME USED AS SUBJECT
Carbon-14
Cosmogenic isotopes
Firn air
Fossil methane
Ice cores
Methane
PERSONAL NAME - PRIMARY RESPONSIBILITY
Hmiel, Benjamin
Petrenko, Vasilii V
ELECTRONIC LOCATION AND ACCESS
Electronic name
مطالعه متن کتاب p
[Thesis]
276903
a
Y
