[A-CC27] アイスコアと古環境モデリング

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

*望月 優子¹、中井 陽一¹、高橋 和也¹、今村 隆史^2,3、本山 秀明⁴ (1.理化学研究所 雪氷宇宙科学研究室、2.東京都環境科学研究所、3.国立環境研究所、4.国立極地研究所)

キーワード：アイスコア、太陽周期、硝酸塩、ドームふじ

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.