[A-CC26] アイスコアと古環境モデリング

[ACC26-P04] 連続融解システムによるドームふじアイスコアのメタン濃度分析

大藪 幾美¹、荒井 美穂^1,4,5、*川村 賢二^1,2,3、北村 享太郎¹、尾形 純¹、東 久美子^1,2 (1.情報・システム研究機構　国立極地研究所、2.総合研究大学院大学、3.海洋研究開発機構、4.山形大学、5.ウェザーニューズ)

キーワード：連続融解分析、アイスコア、メタン、ドームふじ

At the National Institute of Polar Research (NIPR), Continuous Flow Analyses (CFA) system has been developed. In addition to the measurements of melt water (e.g. water isotopes, micro-particles and major ions), the enclosed air is extracted from the water stream and measured for methane (CH₄) concentration by a customized Cavity Ring-Down Spectrometer (CRDS) (Picarro G2301). The CFA system provides data at much higher resolution than classic discrete measurements, which can improve our knowledge and understanding of past climatic variations.

The CH₄ concentration measured by CFA is affected by several factors, impacting precision, accuracy and resolution. The factors include dissolution of CH₄ in meltwater and its imperfect extraction, sample mixing and smoothing in sample lines, and contamination by room air intrusion into the system at the interface between ice samples. The magnitudes of these effects have been investigated, and the data are corrected accordingly. Here, we report the results of various tests for assessing the performance of our CFA for CH₄ measurement. Furthermore, the results of the measurement campaigns of the Dome Fuji ice core, covering the 8.2-kyr cooling event and a part of the last deglaciation, will also be presented.