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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - The Evaluation of the North Atlantic Climate System in UKESM1 Historical Simulations for CMIP6
AU - Robson, Jon
AU - Aksenov, Yevgeny
AU - Bracegirdle, Thomas J.
AU - Dimdore-Miles, Oscar
AU - Griffiths, Paul T.
AU - Grosvenor, Daniel P.
AU - Hodson, Daniel L.R.
AU - Keeble, James
AU - MacIntosh, Claire
AU - Megann, Alex
AU - Osprey, Scott
AU - Povey, Adam C.
AU - Schröder, David
AU - Yang, Mingxi
AU - Archibald, Alexander T.
AU - Carslaw, Ken S.
AU - Gray, Lesley
AU - Jones, Colin
AU - Kerridge, Brian
AU - Knappett, Diane
AU - Kuhlbrodt, Till
AU - Russo, Maria
AU - Sellar, Alistair
AU - Siddans, Richard
AU - Sinha, Bablu
AU - Sutton, Rowan
AU - Walton, Jeremy
AU - Wilcox, Laura J.
N1 - Publisher Copyright: ©2020. The Authors.
PY - 2020/9/30
Y1 - 2020/9/30
N2 - Earth system models enable a broad range of climate interactions that physical climate models are unable to simulate. However, the extent to which adding Earth system components changes or improves the simulation of the physical climate is not well understood. Here we present a broad multivariate evaluation of the North Atlantic climate system in historical simulations of the UK Earth System Model (UKESM1) performed for CMIP6. In particular, we focus on the mean state and the decadal time scale evolution of important variables that span the North Atlantic climate system. In general, UKESM1 performs well and realistically simulates many aspects of the North Atlantic climate system. Like the physical version of the model, we find that changes in external forcing, and particularly aerosol forcing, are an important driver of multidecadal change in UKESM1, especially for Atlantic Multidecadal Variability and the Atlantic Meridional Overturning Circulation. However, many of the shortcomings identified are similar to common biases found in physical climate models, including the physical climate model that underpins UKESM1. For example, the summer jet is too weak and too far poleward; decadal variability in the winter jet is underestimated; intraseasonal stratospheric polar vortex variability is poorly represented; and Arctic sea ice is too thick. Forced shortwave changes may be also too strong in UKESM1, which, given the important role of historical aerosol forcing in shaping the evolution of the North Atlantic in UKESM1, motivates further investigation. Therefore, physical model development, alongside Earth system development, remains crucial in order to improve climate simulations.
AB - Earth system models enable a broad range of climate interactions that physical climate models are unable to simulate. However, the extent to which adding Earth system components changes or improves the simulation of the physical climate is not well understood. Here we present a broad multivariate evaluation of the North Atlantic climate system in historical simulations of the UK Earth System Model (UKESM1) performed for CMIP6. In particular, we focus on the mean state and the decadal time scale evolution of important variables that span the North Atlantic climate system. In general, UKESM1 performs well and realistically simulates many aspects of the North Atlantic climate system. Like the physical version of the model, we find that changes in external forcing, and particularly aerosol forcing, are an important driver of multidecadal change in UKESM1, especially for Atlantic Multidecadal Variability and the Atlantic Meridional Overturning Circulation. However, many of the shortcomings identified are similar to common biases found in physical climate models, including the physical climate model that underpins UKESM1. For example, the summer jet is too weak and too far poleward; decadal variability in the winter jet is underestimated; intraseasonal stratospheric polar vortex variability is poorly represented; and Arctic sea ice is too thick. Forced shortwave changes may be also too strong in UKESM1, which, given the important role of historical aerosol forcing in shaping the evolution of the North Atlantic in UKESM1, motivates further investigation. Therefore, physical model development, alongside Earth system development, remains crucial in order to improve climate simulations.
KW - CMIP6
KW - Earth system model
KW - model evaluation
KW - North Atlantic
U2 - 10.1029/2020MS002126
DO - 10.1029/2020MS002126
M3 - Journal article
AN - SCOPUS:85091662195
VL - 12
JO - Journal of Advances in Modeling Earth Systems
JF - Journal of Advances in Modeling Earth Systems
SN - 1942-2466
IS - 9
M1 - e2020MS002126
ER -