Snow isotopic content change by sublimation

Sokratov, S.A.; Golubev, V.N.

Авторы: Sokratov S.A., Golubev V.N.
Журнал: Journal of Glaciology
Том: 55
Номер: 193
Год издания: 2009
Издательство: International Glaciological Society
Местоположение издательства: United Kingdom
Первая страница: 823
Последняя страница: 828
DOI: 10.3189/002214309790152456
Аннотация: We present results from cold-laboratory observations of changes in isotopic (δ18O and δD) content by sublimation in snow and ice samples under nearly isothermal conditions. The results show large increases in observed δ18O and δD in snow samples within several centimeters of the surface. They contradict the assumption of a non-changing isotopic content due to layer-by-layer transport mechanisms driven by sublimation/desublimation processes. The data also do not support the idea that isotopic changes of snow and firn are limited by the possibility that the ice matrix incorporates the atmospheric water vapor and that forced water-vapor diffusion in the pore space (wind pumping) is a requirement for isotopic content change. The observations show that sublimation from ice samples results in much lower increases in heavy-isotope content in the first several millimetres near the sublimating surface over the same time period, despite sublimation intensities similar to those of the snow samples. The results suggest that continuous phase transitions inside snow (recrystallization) are the process responsible for the isotopic content change because they are the primary mass-exchange mechanism between the snow mass and the surrounding environment. Modeling the isotopic content of the ice matrix therefore requires inclusion of a two-stage process: fractionation at the ice-matrix surface due to repetitive phase transitions, and fractionation due to preferable diffusion of light water isotopes in the pore space. For interpretation of the observed natural isotopic profiles in snow, the first process can be linked to the time a snow layer undergoes recrystallization, while the second process is related to the total ice/snow mass gain/loss determined by the external environmental conditions.
Добавил в систему: Сократов Сергей Альфредович

	ИСТИНА	Войти в систему Регистрация
	ИСТИНА ЦЭМИ РАН
	Главная Поиск Статистика О проекте Помощь

ИСТИНА

ИСТИНА ЦЭМИ РАН

Snow isotopic content change by sublimationстатья

Прикрепленные файлы