Night-time enhanced atmospheric ion concentrations in the marine boundary layer

Abstract

Measurements of atmospheric ions in the size range 0.8–42 nm were conducted at the environmental research station of the University of Crete at Finokalia from April 2008 to April 2009 in the frame of the EUCAARI project. Both positive and negative atmospheric ions were found to have a clear annual cycle, with minimum concentrations in summer. Their concentrations were found to strongly vary on the prevailing meteorology and the presence of pollutants in the atmosphere. There were 53 new particle formation events recorded. It was found that under certain meteorological conditions and atmospheric composition, enhanced ion concentrations can be observed during the night. Overall, 39 night-time events were observed, all of them observed for the negatively charged particles while only 21 were observed for the positively charged particles. Night-time enhanced ion concentrations were more frequent during spring and autumn and no such events were recorded from July to September. It was found that the presence of pollutants in the atmosphere leads to a decrease of atmospheric ions, especially at cluster sizes (1.25–1.66 nm). Additionally, the meteorological conditions affect the abundance of atmospheric ions greatly, a strong anti-correlation was found between air ions concentrations on the one hand and temperature and wind velocity on the other. Enhanced ion concentrations at night were found to be more frequent when air masses had traveled over the island of Crete

New Particle Formation in the Atmosphere: From Molecular Clusters to Global Climate

“…However, there is evidence from aircraft measurements over a large range of latitudes and altitudes that nucleation also takes place during the night in the free troposphere (Hermann et al, ; Lee et al, ). Observations at the ground level have shown some nighttime particle formation events at different locations (Buenrostro Mazon, ; Duplissy et al, ; Junninen et al, ; Kalivitis et al, ; Lehtipalo et al, ; Liu et al, ; Man et al, ; Ortega et al, ; Ortega et al, ; Pushpawela et al, ; Rose et al, ; Russell et al, ; Salimi et al, ; Suni et al, ; Svenningsson et al, ; Wiedensohler et al, ; Zhu et al, ). Nighttime nucleation is characterized by enhanced nuclei mode particle concentrations, but they usually do not show the typical “banana” shaped growth as seen during the daytime NPF events.…”

Floods increase carbon dioxide and methane fluxes in agricultural streams

“…Dinsmore & Billett, 2008;Dinsmore et al, 2010;Wallin, Buffam, Öquist, Laudon, & Bishop, 2010). Mobilisation and loss of streambed sediments during floods can also reduce OM stocks (Atkinson et al, 2008;Biggs, Smith, & Duncan, 1999) that support respiratory gas production as well as the microorganisms themselves. Methane may be particularly sensitive to this effect, as turbulent flows reaerate hypoxic and anoxic habitats (Blaszczak, Delesantro, Urban, Doyle, & Bernhardt, 2019) capable of supporting methanogenesis.…”