Systematic Regional Aerosol Perturbations (SyRAP) in Asia using the
intermediate-resolution global climate model FORTE2
Abstract
Emissions of anthropogenic aerosols are rapidly changing, in amounts,
composition and geographical distribution. In East and South Asia in
particular, strong aerosol trends combined with high population
densities imply high potential vulnerability to climate change. Improved
knowledge of how near-term climate and weather influences these changes
is urgently needed, to allow for better-informed adaptation strategies.
To understand and decompose the local and remote climate impacts of
regional aerosol emission changes, we perform a set of Systematic
Regional Aerosol Perturbations (SyRAP) using the reduced-complexity
climate model FORTE 2. Absorbing and scattering aerosols are perturbed
separately, over East Asia and South Asia, to assess their distinct
influences on climate. In this paper, we first present an updated
version of FORTE2, which includes treatment of aerosol-cloud
interactions. We then document and validate the local responses over a
range of parameters, showing for instance that removing emissions of
absorbing aerosols over both East Asia and South Asia is projected to
cause a local drying, alongside a range of more widespread effects. We
find that SyRAP-FORTE2 is able to reproduce the responses to Asian
aerosol changes documented in the literature, and that it can help us
decompose regional climate impacts of aerosols from the two regions.
Finally, we show how SyRAP-FORTE2 has regionally linear responses in
temperature and precipitation and can be used as input to emulators and
tunable simple climate models, and as a ready-made tool for projecting
the local and remote effects of near-term changes in Asian aerosol
emissions.