Short Black Carbon lifetime inferred from a global set of aircraft observations

Autor(en)

Marianne T. Lund, Bjorn H. Samset, Ragnhild B. Skeie, Duncan Watson-Parris, Joseph M. Katich, Joshua P. Schwarz, Bernadett Weinzierl

Abstrakt

Black Carbon (BC) aerosols substantially affect the global climate. However, accurate simulation of BC atmospheric transportremains elusive, due to shortcomings in modeling and a shortage of constraining measurements. Recently, several studies havecompared simulations with observed vertical concentration profiles, and diagnosed a global-mean BC atmospheric residence timeof <5 days. These studies have, however, been focused on limited geographical regions, and used temporally and spatially coarsemodel information. Here we expand on previous results by comparing a wide range of recent aircraft measurements from multipleregions, including the Arctic and the Atlantic and Pacific oceans, to simulated distributions obtained at varying spatial and temporalresolution. 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 beenpossible. Sampling resolution influences the results, although generally without introducing major bias. However, we uncover largeregional differences in the diagnosed lifetime, in particular in the Arctic. We alsofind that only a weak constraint can be placed inthe African outflow region over the South Atlantic, indicating inaccurate emission sources or model representation of transport andmicrophysical processes. While our results confirm that BC lifetime is shorter than predicted by most recent climate models, theyalso 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.

Organisation(en)

Aerosolphysik und Umweltphysik

Externe Organisation(en)

Center for International Climate and Environmental Research, University of Oxford, National Oceanic and Atmospheric Administration, University of Colorado, Boulder

Journal

npj Climate and Atmospheric Science

Band

1

Anzahl der Seiten

8

ISSN

2397-3722

DOI

https://doi.org/10.1038/s41612-018-0040-x

Publikationsdatum

10-2018

Peer-reviewed

Ja

ÖFOS 2012

103037 Umweltphysik, 103039 Aerosolphysik, 105206 Meteorologie

Schlagwörter

ASJC Scopus Sachgebiete

Global and Planetary Change, Environmental Chemistry, Atmospheric Science

Sustainable Development Goals

SDG 13 – Maßnahmen zum Klimaschutz

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/d7ffb925-af6c-4675-b105-c9da4eb66d29