Surface and tropospheric response of North Atlantic summer climate from paleoclimate simulations of the past millennium

• Published in: Atmosphere
• Main Authors: Pyrina, Maria, Moreno Chamarro, Eduardo, Wagner, Sebastian, Zorita, Eduardo
• Other Authors: Barcelona Supercomputing Center
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI 2021
• Subjects: Àrees temàtiques de la UPC::Enginyeria agroalimentària::Ciències de la terra i de la vida; Paleoclimatology; Earth systems data and models; Climatic changes; North Atlantic Region; Solar forcing; TSI; Last millennium; Paleoclimate simulations; CESM-LME; North Atlantic; Surface climatic response; Simulacio per ordinador; Canvis climàtics; Canada; Greenland
• Online Access: http://hdl.handle.net/2117/345146; https://doi.org/10.3390/atmos12050568

We investigate the effects of solar forcing on the North Atlantic (NA) summer climate, in climate simulations with Earth System Models (ESMs), over the preindustrial past millennium (AD 850–1849). We use one simulation and a four-member ensemble performed with the MPI-ESM-P and CESM-LME models, respectively, forced only by low-scaling variations in Total Solar Irradiance (TSI). We apply linear methods (correlation and regression) and composite analysis to estimate the NA surface and tropospheric climatic responses to decadal solar variability. Linear methods in the CESM ensemble indicate a weak summer response in sea-level pressure (SLP) and 500-hPa geopotential height to TSI, with decreased values over Greenland and increased values over the NA subtropics. Composite analysis indicates that, during high-TSI periods, SLP decreases over eastern Canada and the geopotential height at 500-hPa increases over the subtropical NA. The possible summer response of SSTs is overlapped by model internal variability. Therefore, for low-scaling TSI changes, state-of-the-art ESMs disagree on the NA surface climatic effect of solar forcing indicated by proxy-based studies during the preindustrial millennium. The analysis of control simulations indicates that, in all climatic variables studied, spurious patterns of apparent solar response may arise from the analysis of single model simulations. This research partly received external funding from the framework of the European Initial Marie Curie Training network ARAMACC (Annually resolved Archives of Marine Climate Change). This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 604802. Peer Reviewed Postprint (published version)