Seasonality of ⁷Be concentrations in Europe and influence of tropopause height

Abstract

A B S T R A C TThis study aims at analysing the latitudinal variability of both the yearly and seasonal pattern of 7 Be shows a clear increasing tendency in the period and generally tends to increase with decreasing latitude. The seasonal pattern generally shows maxima during the warm period and minima during the cold one. The seasonal variogram analysis points out a good spatial correlation for TPH data while a weaker one is observed for 7 Be, having TPH a larger influence on 7 Be during summer. The influence of TPH on 7 Be exhibits a large spatial variability, with a clear gap between south and north in the area of the polar front jet. The results identify the presence of two main groups, in particular separating between stations located in northern Europe (50 8N and higher) and stations in southern Europe (south of 50 8N). A similar behaviour for stations located in the same geographical area is also observed when looking at the day of maximum impact of TPH on 7Be concentrations. The results suggest that 7 Be concentrations respond in different time ranges to changes in the TPH, observing seasonal differences in each group. These results represent the first European approach to the understanding of the TPH impact on 7 Be concentrations at surface levels.

Dynamics of beryllium-7 specific activity in relation to meteorological variables, tropopause height, teleconnection indices and sunspot number

“…This tropopause height periodicity of ∼2.5 years has been identified previously [62]. A positive correlation between the tropopause height and the 7 Be specific activity in surface air was observed by [17,18,50]. Similarly, the differences in the type of changes from one year to another also seemed negligible.…”

“…only after explicit request. More information on the REMdb can be found on its web page (https://rem.jrc.ec.europa.eu/) and in [21,49,50]. The measurements conducted in Helsinki represent the largest set with more than 4 000 data points over 1987-2011.…”

A study of the influence of tropospheric subsidence on spring and summer surface ozone concentrations at the JRC Ispra station in northern Italy

“…It has been reported that tropospheric ozone levels as well as surface ozone concentrations have increased significantly during the last couple of centuries (Volz and Kley, 1988;Forster et al, 2007;Monks et al, 2015;Gaudel et al, 2018). Ozone is an important greenhouse gas and can cause adverse effects on human health and also have negative impacts on vegetation and materials (Ito et al, 2005;Van Dingenen et al, 2009;Hollaway et al, 2012). Tropospheric ozone is mainly produced in the troposphere through photochemical reactions of precursor pollutants but it does also originate from stratospheric intrusions (Volz and Kley, 1988;Staehelin et al, 1994).…”

“…Most of 7 Be is produced in the stratosphere and about one-third in the troposphere, especially in its upper part (O'Brien, 1979). After their formation, 7 Be atoms are mostly attached to atmospheric particles and so their atmospheric concentrations are greatly influenced by transport and deposition processes of particles (Jaenicke, 1988;Feely et al, 1989;Papastefanou and Ioannidou, 1995;Koch et al, 1996;Bourcier et al, 2011;Duenas et al, 2011;Lozano et al, 2012;Steinmann et al, 2013;Hernández-Ceballos et al, 2016).…”

“…Due to the exchange and removal processes in the atmosphere, the 7 Be concentration in air at ground level varies strongly with the season while 7 Be production rates in the atmosphere remain relatively constant (Durana et al, 1996;Masarik and Beer, 1999). In general, 7 Be surface concentrations show a maximum in late summer (Reiter et al, 1983;Feely et al, 1989;Bourcier et al, 2011;Hernández-Ceballos et al, 2016).…”