Short black carbon lifetime inferred from a global set of aircraft observations

Black Carbon (BC) aerosols substantially affect the global climate. However, accurate simulation of BC atmospheric transport remains elusive, due to shortcomings in modeling and a shortage of constraining measurements. Recently, several studies have compared simulations with observed vertical concen...

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Main Authors: Lund, M, Samset, B, Skeie, R, Watson-Parris, D, Katich, J, Schwarz, J, Weinzierl, B
Format: Journal article
Izdano: Nature Research 2018
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author Lund, M
Samset, B
Skeie, R
Watson-Parris, D
Katich, J
Schwarz, J
Weinzierl, B
author_facet Lund, M
Samset, B
Skeie, R
Watson-Parris, D
Katich, J
Schwarz, J
Weinzierl, B
author_sort Lund, M
collection OXFORD
description Black Carbon (BC) aerosols substantially affect the global climate. However, accurate simulation of BC atmospheric transport remains elusive, due to shortcomings in modeling and a shortage of constraining measurements. Recently, several studies have compared simulations with observed vertical concentration profiles, and diagnosed a global-mean BC atmospheric residence time of <5 days. These studies have, however, been focused on limited geographical regions, and used temporally and spatially coarse model information. Here we expand on previous results by comparing a wide range of recent aircraft measurements from multiple regions, including the Arctic and the Atlantic and Pacific oceans, to simulated distributions obtained at varying spatial and temporal resolution. By perturbing BC removal processes and using current best-estimate emissions, we confirm a constraint on the global-mean BC lifetime of <5.5 days, shorter than in many current global models, over a broader geographical range than has so far been possible. Sampling resolution influences the results, although generally without introducing major bias. However, we uncover large regional differences in the diagnosed lifetime, in particular in the Arctic. We also find that only a weak constraint can be placed in the African outflow region over the South Atlantic, indicating inaccurate emission sources or model representation of transport and microphysical processes. While our results confirm that BC lifetime is shorter than predicted by most recent climate models, they also cast doubt on the usability of the concept of a “global-mean BC lifetime” for climate impact studies, or as an indicator of model skill.
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spelling oxford-uuid:8894aa5f-0340-4502-a750-58806b5a96972022-03-26T22:18:21ZShort black carbon lifetime inferred from a global set of aircraft observationsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:8894aa5f-0340-4502-a750-58806b5a9697Symplectic Elements at OxfordNature Research2018Lund, MSamset, BSkeie, RWatson-Parris, DKatich, JSchwarz, JWeinzierl, BBlack Carbon (BC) aerosols substantially affect the global climate. However, accurate simulation of BC atmospheric transport remains elusive, due to shortcomings in modeling and a shortage of constraining measurements. Recently, several studies have compared simulations with observed vertical concentration profiles, and diagnosed a global-mean BC atmospheric residence time of <5 days. These studies have, however, been focused on limited geographical regions, and used temporally and spatially coarse model information. Here we expand on previous results by comparing a wide range of recent aircraft measurements from multiple regions, including the Arctic and the Atlantic and Pacific oceans, to simulated distributions obtained at varying spatial and temporal resolution. By perturbing BC removal processes and using current best-estimate emissions, we confirm a constraint on the global-mean BC lifetime of <5.5 days, shorter than in many current global models, over a broader geographical range than has so far been possible. Sampling resolution influences the results, although generally without introducing major bias. However, we uncover large regional differences in the diagnosed lifetime, in particular in the Arctic. We also find that only a weak constraint can be placed in the African outflow region over the South Atlantic, indicating inaccurate emission sources or model representation of transport and microphysical processes. While our results confirm that BC lifetime is shorter than predicted by most recent climate models, they also cast doubt on the usability of the concept of a “global-mean BC lifetime” for climate impact studies, or as an indicator of model skill.
spellingShingle Lund, M
Samset, B
Skeie, R
Watson-Parris, D
Katich, J
Schwarz, J
Weinzierl, B
Short black carbon lifetime inferred from a global set of aircraft observations
title Short black carbon lifetime inferred from a global set of aircraft observations
title_full Short black carbon lifetime inferred from a global set of aircraft observations
title_fullStr Short black carbon lifetime inferred from a global set of aircraft observations
title_full_unstemmed Short black carbon lifetime inferred from a global set of aircraft observations
title_short Short black carbon lifetime inferred from a global set of aircraft observations
title_sort short black carbon lifetime inferred from a global set of aircraft observations
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