[A-OS12] Physical, biogeochemical, and ecological processes and variability in the Indian Ocean

[AOS12-03] ジャワ島南の沿岸湧昇に関連する表層クロロフィルの季節内変動

*堀井 孝憲¹、Siswanto Eko²、Iskandar Iskhaq³、植木 巌¹ (1.海洋研究開発機構 地球環境部門 海洋観測研究センター、2.海洋研究開発機構 地球環境部門 地球表層システム研究センター、3.Faculty of Mathematics and Natural Sciences, Sriwijaya University, Indonesia)

キーワード：表層クロロフィル、ジャワ島、インド洋ダイポール現象

Coastal upwelling along the southern coast of Java brings cold and nutrient-rich subsurface water upward and plays an important role in controlling ocean surface heat balance, biogeochemical balance, coastal ecosystem, and regional fisheries. To understand the coastal upwelling, we investigated satellite-based Chlorophyll-a data south of Java, with a focus on the seasonal and intraseasonal-scale variability. We first interpolated the data and produced daily timeseries. The spectrum analysis showed that annual, semi-annual, and intraseasonal (20-60-day) variations were significant in the Chlorophyll-a variations. The Chlorophyll-a peaks were accompanied with decreases in the local sea level and sea surface temperature, suggesting a coastal upwelling of cold and nutrient-rich subsurface water at the intraseasonal timescale. A relationship between the intraseasonal Chlorophyll-a variations and the Indian Ocean Dipole will be discussed.