Active Nitrogen Cycle Driven by Solar Radiation in Clean Desert Air. Issue 4 (23rd April 2022)

• Record Type: Journal Article
• Authors: Wu, Feng; Hu, Tafeng; Cao, Junji; Guo, Xiao; Li, Guohui; Zhang, Ting; Yang, Yikun; Zhao, Chuanfeng; Zhang, Daizhou
• Is Part Of: Earth's future. Volume 10:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-23
• Subjects: reactive nitrogen compounds -- desert air -- surface emission -- diurnal cycle -- solar radiation -- global atmosphere; Environmental sciences -- Periodicals; Environmental sciences; Periodicals; 550
• DOI: 10.1029/2021EF002451
• Languages: English
• ISSNs: 2328-4277

Abstract

Abstract: Deserts have been recognized as constantly releasing reactive nitrogen compounds to the atmosphere due to the subsoil‐storage leaching and surface‐deposit evaporation induced by solar radiative heating. However, this release and the consequent response of the nitrogen cycles in desert air have not been evaluated and are overlooked in most regional and global models. In our nitrate measurements, including nitric acid and particulate nitrate, in clean air, that is, in the absence of or with minor anthropogenic influences, in a Chinese desert, diurnal nitrate variations consisting of daytime increases and nighttime decreases were observed in the range of 1.3–3.7 μ gm −3 in summer, 0.1–2.6 μ gm −3 in spring, and 0.2–1.3 μ gm −3 in autumn. These values are considerably higher than those observed in remote marine and forest areas. Simulations with a regional transport model demonstrate that the variation could be largely accounted for by the oxidation of soil‐emitted reactive nitrogen compounds by photochemical‐reactions products. These results indicate an active nitrogen cycle in clean desert air, which is the consequence of the coordination of solar radiation‐induced surface soil emission and subsequent photochemical reactions. Satellite data of NO2 further indicate possible similar cycles in most major desert areas worldwide. By including this nitrogen cycle in the vast desert areas and its subsequent effects, such as those on ozone chemistry, climate models may thus provide a better understanding of the global nitrogen budget in the historical and developing Earth ecosystems. Plain Language Summary: We found a considerable but not widely known response of atmospheric nitrogen cycle to the emission of reactive nitrogen compounds from desert soils, which is very likely taking place in most of the major desert areas over the world. The response and its subsequent effects, such as on ozone, should have been one of the key parts of atmospheric chemistry in the long historical earth environment evolution, but unfortunately these points have not been taken into account so far in any climate models. The finding of this study will reduce the uncertainties in our understanding on the global nitrogen balance and benefit model and field studies on the roles of the desert‐sourced atmospheric nitrogen cycling in the historical and developing Earth ecosystem. Key Points: An active diurnal cycle of nitrogen compounds driven by solar radiation was found in clean air at a Chinese desert Satellite data indicate that similar cycles likely occur in the air of most desert areas worldwide Including the cycle in climate models is expected to deepen understandings on global nitrogen budget in the evolution of Earth ecosystems