Wet deposition of 7Be and 10Be in Xi'an, China: Variation characteristics and influencing factors

Cosmogenic Be-7 and Be-10 are effective tracers for studying atmospheric dynamics and Earth's surface processes, with over 90% of these isotopes reaching the surface via wet deposition. However, the characteristics and influencing factors of Be-7 and Be-10 wet deposition remain unclear in different regions, limiting the precision of these nuclides as tracers of environmental change. This study analyzes the annual variation of Be-7 and Be-10 wet deposition in Xi'an and examines the impact of precipitation on their deposition. Ultra-trace levels of Be-7 and Be-10 in precipitation were synchronously measured using state-of-the-art accelerator mass spectrometry. One-year (July 30, 2020 to September 3, 2021), high-frequency (individual rain events) and time-synchronized series of observations of Be-7 and Be-10 wet deposition data (n = 49) were analyzed. The total annual wet deposition fluxes of Be-7 and Be-10 in central China (34.22 degrees N, 109.01 degrees E) for 2020/21 were (218 +/- 24) x 10(8) atomsm(-2)yr(-1) and (314 +/- 16) x 10(8) atomsm(-2)yr(-1), respectively. Precipitation amount, intensity, and duration were quantitatively analyzed for their effects on total wet deposition flux, mean concentration, washout ratio, deposition velocity, and scavenging coefficient of Be-7 and Be-10 during individual rain events. The results indicate that precipitation amount is the most significant factor influencing the wet deposition flux of both nuclides.