Journal Article

The role of highly oxygenated organic molecules in the Boreal aerosol-cloud-climate system

Hao, Liqing, Boy, Michael, Ehn, Mikael, Virtanen, Annele, Kurtén, Theo, Petäjä, Tuukka, Olenius, Tinja, Roldin, Pontus, Heikkinen, Liine, Riipinen, Ilona, Worsnop, Douglas R., Xavier, Carlton, Pichelstorfer, Lukas, Rissanen, Matti P., Clusius, Petri, Öström, Emilie, Rantala, Pekka, Sarnela, Nina, Hyttinen, Noora, Kulmala, Markku, Elm, Jonas, Vehkamäki, Hanna

2019

Overview

Over Boreal regions, monoterpenes emitted from the forest are the main precursors for secondary organic aerosol (SOA) formation and the primary driver of the growth of new aerosol particles to climatically important cloud condensation nuclei (CCN). Autoxidation of monoterpenes leads to rapid formation of Highly Oxygenated organic Molecules (HOM). We have developed the first model with near-explicit representation of atmospheric new particle formation (NPF) and HOM formation. The model can reproduce the observed NPF, HOM gas-phase composition and SOA formation over the Boreal forest. During the spring, HOM SOA formation increases the CCN concentration by ~10 % and causes a direct aerosol radiative forcing of −0.10 W/m 2 . In contrast, NPF reduces the number of CCN at updraft velocities < 0.2 m/s, and causes a direct aerosol radiative forcing of +0.15 W/m 2 . Hence, while HOM SOA contributes to climate cooling, NPF can result in climate warming over the Boreal forest. Forests emit compounds into the atmosphere that are oxidized into highly oxygenated molecules that serve as precursors for cloud condensation nuclei–a process that impacts the climate, but is poorly represented in models. Here the authors create a new model that accurately depicts highly oxygenated molecule and climate dynamics over Boreal forests.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 119/118 / 140/58 / 639/638/169/824 / 704/106/35 / 704/106/694/1108 / 704/172/169/824 / Aerosols / Atmosphere / Atmospheric aerosols / Atoms & subatomic particles / Autoxidation / Boreal forests / Chemistry / Climate / Climate change / Climate Science / Climate system / Condensation nuclei / Earth and Related Environmental Sciences / Experiments / Forests / Geochemistry / Geokemi / Geovetenskap och relaterad miljövetenskap / Global warming / Humanities and Social Sciences / Klimatvetenskap / Meteorologi och atmosfärsvetenskap / Meteorology and Atmospheric Sciences / Monoterpenes / multidisciplinary / Natural Sciences / Naturgeografi / Naturvetenskap / Nitrates / Organic chemistry / Oxygenation / Phase composition / Physical Geography / Physics / Radiation / Radiative forcing / Science / Science (multidisciplinary) / Simulation / Taiga / Volatility