[A-CC27] Ice cores and paleoenvironmental modeling

[ACC27-02] Solar activity cycles embedded in nitrate concentrations in Dome Fuji ice cores

*Yuko MOTIZUKI¹, Yoichi Nakai¹, Kazuya Takahashi¹, Takashi Imamura^2,3, Hideaki Motoyama⁴ (1.Astro-Glaciology Lab., RIKEN, 2.Tokyo Metropolitan Research Institute for Environmental Protection, 3.National Institute for Environmental Studies, 4.National Institute of Polar Research)

Keywords:ice core, solar cycle, ninitrate, Dome Fuji

Ice cores are known to yield information about past solar activities as well as information about past climate. We report time series analyses of annually-resolved nitrate concentration variations in an ice core DF01 drilled in 2001 at the Dome Fuji station in East Antarctica. The target period is from CE 1610 to 1904, during which sunspot numbers were observed by telescopes. Our analyses revealed clear evidence of ∼11, ∼22, and ∼90-year periodicities, comparable to the respective periodicities of the well-known Schwabe, Hale, and Gleissberg solar cycles. It is shown for the first time that ice core nitrate concentrations can be used as a proxy for past solar activity on decadal to multidecadal time scales. Furthermore, we detected 11-year and 22-year periodicities in nitrate concentrations during the Maunder Minimum (1645–1715), when sunspots were almost absent. This discovery may support the cyclic behavior of the solar dynamo during the grand solar minimum.

In this presentation, we will also discuss the results of the DFS10 ice core, which was drilled in 2010 about 10 km south of the Dome Fuji station.