Cosmogenic ¹⁰Be/⁷Be as a probe of atmospheric transport processes

Abstract

Using accelerator spectrometry to measure 10Be, the ratio of the cosmogenic isotopes 10Be/7Be has been determined in 5 stratospheric and 2 South Pole ground level air filters. It is argued that this ratio can be a very sensitive probe of the origin, residence time, and mixing patterns of different atmospheric air masses, and in particular for identifying incursions of stratospheric air into the troposphere.

What Is Missing from Our Understanding of Long‐Term Solar and Heliospheric Activity?

“…This radioisotope is produced in collisions of cosmic rays with nitrogen and oxygen in the Earth's atmosphere, some of which is eventually captured in aerosols that precipitate onto polar ice. The timescale for this isotope to remain in the atmosphere is $1-2 yr (Raisbeck et al 1981). The cosmic-ray flux incident on Earth, in turn, is modulated by the heliospheric field: their passage from the outer heliosphere toward Earth is hampered by frequent scattering off the heliospheric magnetic field and the irregularities traveling in it (Cliver & Ling 2001).…”

Stratosphere‐troposphere exchange: A review, and what we have learned from STACCATO

“…Furthermore, 7 Be attaches to aerosols and is removed from the atmosphere by wet scavenging [Gerasopoulos et al, 2001]. Therefore, Raisbeck et al [1981] suggested to use the concentration ratio of two radionuclides ( 7 Be and 10 Be), which are both mostly produced in the stratosphere and are both scavenged in the same way. The ratio ( 10 Be)/( 7 Be) is thus not affected by the removal process.…”

“…Various measurements, including O 3 , 7 Be and meteorological parameters, were carried out at five mountain stations in the Alps, Northern Apennines, and in Northern Greece. Furthermore, for the first time 10 Be was sampled at two stations continuously during the project in order to follow the ideas of Raisbeck et al [1981] and Dibb et al [1994] to estimate the impact of STT on surface O 3 .…”

10Be/7Be implies the contribution of stratosphere-troposphere transport to the winter-spring surface O3 variation observed on the Tibetan Plateau

“…Both 7 Be and 10 Be are absorbed easily by sub-micrometersize aerosol particles once produced. 7 Be as a natural tracer of downward transport from the upper atmosphere had been gradually established since the 1960s, and the first application of 10 Be/ 7 Be as a stratospheric tracer was addressed by Rasebeck et al [1] in 1981. The half -lives of 7 Be and 10 Be are 53.3 d and 1.5×10 6 a, respectively, while the average age of the stratospheric air mass is ~1.5 a.…”