消えたエアロゾルと雲凝結核を説明する新しいモデル(New Model Explains Missing Aerosol and Cloud Condensation Nuclei)

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2024-06-14 パシフィック・ノースウェスト国立研究所(PNNL)

新しい研究では、大気中のエアロゾル粒子が地球の気候に与える影響を調査しました。エネルギー超規模地球システムモデル(E3SM)を使用して、凝縮性ガス分子からの新しい粒子形成(NPF)メカニズムと前駆体ガスの化学変換をモデル化しました。結果、これらの現代的なNPFメカニズムが、エアロゾルが豊富な地域や雲の形成に影響を与える地域で支配的であることが判明しました。これにより、エアロゾルの気候効果を正確に見積もり、前駆体ガスや一次粒子の排出源に効果的な対策を立てることが可能となります。この研究は、地域および世界規模でのNPFメカニズムの重要性を再評価し、気候変動の評価や将来予測に重要な示唆を提供します。

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大気中の新粒子形成メカニズムにおけるグローバルな変動性 Global variability in atmospheric new particle formation mechanisms

Bin Zhao,Neil M. Donahue,Kai Zhang,Lizhuo Mao,Manish Shrivastava,Po-Lun Ma,Jiewen Shen,Shuxiao Wang,Jian Sun,Hamish Gordon,Shuaiqi Tang,Jerome Fast,Mingyi Wang,Yang Gao,Chao Yan,Balwinder Singh,Zeqi Li,Lyuyin Huang,Sijia Lou,Guangxing Lin,Hailong Wang,Jingkun Jiang,Aijun Ding,Wei Nie,… Lin Wang
Nature  Published:12 June 2024
DOI:https://doi.org/10.1038/s41586-024-07547-1

figure 1

Abstract

A key challenge in aerosol pollution studies and climate change assessment is to understand how atmospheric aerosol particles are initially formed1,2. Although new particle formation (NPF) mechanisms have been described at specific sites3,4,5,6, in most regions, such mechanisms remain uncertain to a large extent because of the limited ability of atmospheric models to simulate critical NPF processes1,7. Here we synthesize molecular-level experiments to develop comprehensive representations of 11 NPF mechanisms and the complex chemical transformation of precursor gases in a fully coupled global climate model. Combined simulations and observations show that the dominant NPF mechanisms are distinct worldwide and vary with region and altitude. Previously neglected or underrepresented mechanisms involving organics, amines, iodine oxoacids and HNO3 probably dominate NPF in most regions with high concentrations of aerosols or large aerosol radiative forcing; such regions include oceanic and human-polluted continental boundary layers, as well as the upper troposphere over rainforests and Asian monsoon regions. These underrepresented mechanisms also play notable roles in other areas, such as the upper troposphere of the Pacific and Atlantic oceans. Accordingly, NPF accounts for different fractions (10–80%) of the nuclei on which cloud forms at 0.5% supersaturation over various regions in the lower troposphere. The comprehensive simulation of global NPF mechanisms can help improve estimation and source attribution of the climate effects of aerosols.

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1702地球物理及び地球化学
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