Solar arctic-mediated climate variation on multidecadal to centennial timescales: empirical evidence, mechanistic explanation, and testable consequences

• Main Author: Willie W. -h. Soon
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2009
• Subjects: Arctic; Pacific; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.306.5163; http://icecap.us/images/uploads/Soon09-June4-PGEO_30n02_144-184-Soon.pdf

Abstract: Soon (2005) showed that the variable total solar irradiance (TSI) could explain, rather surprisingly, well over 75 % of the variance for the decadally smoothed Arctic-wide surface air temperature over the past 130 years. The present paper provides additional empirical evidence for this physical connection, both through several newly published high-resolution paleo-proxy records and through robust climate-process modeling outputs. This paper proposes a mechanistic explanation, involving: (1) the variable strength of the Atlantic meridional overturning circulation (MOC) or thermohaline circulation (THC); (2) the shift and modulation of the Inter-Tropical Convergence Zone (ITCZ) rainbelt and tropical Atlantic ocean conditions; and (3) the intensity of the wind-driven subtropical and subpolar gyre circulation, across both the North Atlantic and North Pacific. A unique test of this proposed solar TSI–Arctic thermal–salinity–cryospheric coupling mechanism is the 5- to 20-year delay effect on the peak Atlantic MOC flow rate centered near 30–35°N, and on sea surface temperature (SST) for the tropical Atlantic. The solar Arctic–mediated climate mechanism on multidecadal to centennial timescales presented here can be compared with and differentiated from both the related solar TSI and UV irradiance forcing on decadal timescales. The ultimate goal of this research is to gain sufficient mechanistic details so that the proposed solar–Arctic climate connection on multidecadal to centennial timescales can be confirmed or falsified. A further incentive is to expand this physical connection to longer, millennial-scale variability as motivated by the multiscale climate interactions shown by Braun et al. (2005), Weng (2005), and Dima and Lohmann (2009). [Key words: solar–Arctic climate connection, total solar irradiance, Atlantic meridional overturning circulation, climate variability.]