Spatial scales of climate response to inhomogeneous radiative forcing

• Published in: Journal of Geophysical Research
• Main Authors: Shindell, Drew, Schulz, Michael, Ming, Yi, Takemura, Toshihiko, Faluvegi, Greg, Ramaswamy, V.
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Arctic; Climate change
• Online Access: https://hal.science/hal-03201079; https://hal.science/hal-03201079/document; https://hal.science/hal-03201079/file/2010JD014108.pdf; https://doi.org/10.1029/2010JD014108

International audience The distances over which localized radiative forcing influences surface temperature have not been well characterized. We present a general methodology to analyze the spatial scales of the forcing/response relationship and apply it to simulations of historical aerosol forcing and response in four climate models. We find that the surface temperature response is not strongly sensitive to the longitude of forcing but is fairly sensitive to latitude. Surface temperature responses in the Arctic and the Southern Hemisphere extratropics, where forcing was small, show little relationship to local forcing. Restricting the analysis to 30°S-60°N, where nearly all the forcing was applied, shows that forcing strongly influences response out to ∼4500 km away examining all directions. The meridional length of influence is somewhat shorter (∼3500 km or 30°), while it extends out to at least 12,000 km in the zonal direction. Substantial divergences between the models are seen over the oceans, whose physical representations differ greatly among the models. Length scales are quite consistent over 30°S-60°N land areas, however, despite differences in both the forcing applied and the physics of the models themselves. The results suggest that better understanding of regionally inhomogeneous radiative forcing would lead to improved projections of regional climate change over land areas. They also provide quantitative estimates of the spatial extent of the climate impacts of pollutants, which can extend thousands of kilometers beyond polluted areas, especially in the zonal direction.