Characterization and causes of North Atlantic cold bias in climate models ...

• Main Authors: Lin, Xia, Massonnet, Francois, Barbieri de Azevedo, Helena
• Format: Conference Object
• Language: unknown
• Published: GFZ German Research Centre for Geosciences 2023
• Subjects: North Atlantic
• Online Access: https://dx.doi.org/10.57757/iugg23-2053; https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018819

<!--!introduction!--> The North Atlantic sea surface temperature (SST) cold bias is a remarkable feature of general circulation models (GCMs). This bias is a primary concern in climate science because they directly affect the skill of predictions and the confidence in projections on the North Hemisphere climate. Here the characterization and causes of the cold bias are investigated by combining Atmospheric, Ocean, and Coupled Model Inter-comparison Project (AMIP6/OMIP6/CMIP6) simulations with observations. It is found that the cold North Atlantic SST bias in CMIP6 is primarily caused by weak heat transport in ocean models induced by weak Gulf Stream currents. The weak atmospheric fluctuations induced shallow mixed layer depth also plays a role. These biases are much reduced by increasing the atmospheric and oceanic model resolution to around 1º and 0.25º in HadGEM3-GC31-MM, respectively. The radiation heat flux bias in AMIP6 and CMIP6 model are small. The large turbulent heat flux bias linked to SST ... : The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) ...