Chemistry within aqueous atmospheric aerosols and raindrops

Abstract

1] Chemical and physical Earth models agree little as to the radioactive power of the planet. Each predicts a range of radioactive powers, overlapping slightly with the other at about 24 TW, and together spanning 14-46 TW. Approximately 20% of this radioactive power (3-8 TW) escapes to space in the form of geoneutrinos. The remaining 11-38 TW heats the planet with significant geodynamical consequences, appearing as the radiogenic component of the 43-49 TW surface heat flow. The nonradiogenic component of the surface heat flow (5-38 TW) is presumably primordial, a legacy of the formation and early evolution of the planet. A constraining measurement of radiogenic heating provides insights to the thermal history of the Earth and potentially discriminates chemical and physical Earth models. Radiogenic heating in the planet primarily springs from unstable nuclides of uranium, thorium, and potassium. The paths to their stable daughter nuclides include nuclear beta decays, producing geoneutrinos. Large subsurface detectors efficiently record the energy but not the direction of the infrequent interactions of the highest-energy geoneutrinos, originating only from uranium and thorium. The measured energy spectrum of the interactions estimates the relative amounts of these heatproducing elements, while the intensity estimates planetary radiogenic power. Recent geoneutrino observations in Japan and Italy find consistent values of radiogenic heating. The combined result mildly excludes the lowest model values of radiogenic heating and, assuming whole mantle convection, identifies primordial heat loss. Future observations have the potential to measure radiogenic heating with better precision, further constraining geological models and the thermal evolution of the Earth. This review presents the science and status of geoneutrino observations and the prospects for measuring the radioactive power of the planet.

Secondary organic aerosol formation in cloud droplets and aqueous particles (aqSOA): a review of laboratory, field and model studies

“…Many compounds such as di-and oxocarboxylic acids, esters and organosulfur compounds that do not have any (efficient) gas phase sources have been found in rain and cloud water samples (Graedel and Weschler, 1981;Blando and Turpin, 2000); their presence in droplets does not necessarily imply that they have been formed in this dilute aqueous phase. The presence of aldehyde-sulfur(IV) adducts (e.g.…”

Organic aerosol and global climate modelling: a review

“…However, the chemical pathways in their model cannot predict the high amounts of dicarboxylic acids found in aerosol samples. Graedel and Weschler (1981) give a detailed overview of chemical conversions of organics in aqueous atmospheric aerosols. They show that aldehydes in the gas phase might act as precursors for organic acid formation in the aqueous phase which is reflected in similar concentration patterns for both species groups.…”

Droplet activation of wet particles: development of the Wet CCN approach

“…In addition to their key roles in the prediction of climate changes (IPCC, 2007), clouds are also important drivers of atmospheric chemistry, impacting aerosol formation, modification, and removal (Graedel and Weschler, 1981;Blando and Turpin, 2000;Ervens et al, 2011). One aspect of clouds that is presently not well understood is the beginning of their lifetime: cloud droplet activation.…”