Wykład prof. Thomasa Rockmanna

W piątek 29 listopada br., w ramach Distinguished Lecture Program, prof. Thomas Rockmann (Utrecht University) wygłosi wykład pt. "Reconstructing changes in atmospheric trace gases in the industrial era from isotope mecasurements on air extracted from polar firn".

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Seminarium odbędzie się na Wydziale Fizyki i Informatyki Stosowanej (bud. D-10/A) o godz: 12:15.

Abstract:

In many cases, direct and comprehensive measurements on atmospheric composition are only available for the last 2-3 decades. To obtain information on changes before that time, air archives are needed, and polar ice cores are excellent archives of past atmospheric composition. Whereas available ice core records can go almost a million years back in time, air extracted from the firn, the top part of an ice sheet, can be used to cover the period of several decades to a century back in time. We have measured mixing ratio and isotopic composition of numerous trace gases on air samples extracted from firn at the NEEM ice core drilling in Greenland. These data are combined with previously published measurements to reconstruct consistent time series of isotope variations over the past 6 decades using a state of the art firn air model. It is important to take into account gravitational and diffusive fractionation in the firn air, which are in some cases of the same order as the actual isotope changes in the atmosphere.

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