Coral-based reconstruction of salinity and temperature variability in the southern Makassar Strait and its Influence on the Indonesian Throughflow

基于珊瑚的望加锡海峡南部盐度和温度变化重建及其对印度尼西亚通流的影响

• 批准号: 1211110
• 负责人: Braddock Linsley
• 金额: $ 28.32万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1211110&HistoricalAwards=false
• 关键词: Coral; based; reconstruction; salinity; temperature

The Indonesian Throughflow (ITF) is the main conduit for transporting surface and upper thermocline water from the western equatorial Pacific into the Indian Ocean. The volume and temperature of the ITF varies seasonally due to the seasonal influx of low salinity surface water from the South China and Java Seas into the Makassar Strait during the northern winter monsoon. This low salinity "plug" generates a northward pressure gradient in the Makassar Strait that seasonally inhibits the flow of warm surface water in the far western Pacific Ocean from freely flowing southward into the Indian Ocean. The net result is a cooling and freshening of the Indian Ocean thermocline. Despite the oceanographic significance of this seasonal freshening of the Makassar Strait on the ITF, little is known about century to decadal-scale variability of salinity in the Makassar Strait. Previous low-resolution studies based on sediment cores in the Makassar Strait indicate that during the Little Ice Age (~1600-1850 AD), salinity and sea surface temperature in the strait were both reduced. This research utilizes Porites sp. coral cores from Kapoposang in the southern Makassar Strait near S.W. Sulawesi and from Gili Meno in the Lombok Strait near Bali to develop partially replicated, near-monthly resolution, trace element (Sr/Ca) and stable isotope (d18Osw) records spanning the last 250 years. Results show that coral Sr/Ca variability accurately tracks the annual bi-modal sea surface temperature cycle. The research will enhance understanding of salinity and SST variability in this critical strait in order to constrain ITF variability over the last 250 years. Changes in the freshwater budget of the southern Makassar Strait are expected to alter the intensity of the "freshwater plug", with lower salinity in the Makassar Strait surface layer leading to a cooler ITF. Funding supports a postdoctoral associate and research experiences for undergraduates.

印度尼西亚人的遍布（ITF）是将西赤道太平洋向印度洋传输表面和上热跃层水的主要管道。 ITF的体积和温度在季节性的季节性在北部季风期间从中国南部和Java海中涌入Makassar海峡的季节性涌入季节而变化。 这种低盐度“塞”在麦卡萨尔海峡产生了向北的压力梯度，该海峡在季节性地抑制了远西太平洋中温暖的地表水的流动，​​从自由向南流入印度洋。最终结果是印度洋热跃层的冷却和清新。尽管这种在ITF上的Makassar海峡季节性清新的海洋学意义，但对于Makassar海峡中盐度的十年级变异而言，鲜为人知。先前基于麦卡萨尔海峡中沉积物核心的低分辨率研究表明，在小冰河时代（〜1600-1850 AD），海峡中的盐度和海面温度都降低了。 这项研究利用了Porites sp。来自S.W.附近南部Makassar海峡的Kapoposang的珊瑚岩心Sulawesi和来自巴厘岛附近Lombok海峡的Gili Meno，以部分复制，几乎一月份的分辨率，痕量元素（SR/CA）和稳定的同位素（D18OSW）记录，涉及过去250年。结果表明，珊瑚SR/CA变异性准确地跟踪了年度双模式的海面温度周期。这项研究将增强对这一关键海峡中盐度和SST变异性的理解，以限制过去250年中ITF的可变性。 预计南部Makassar海峡的淡水预算的变化将改变“淡水塞”的强度，而Makassar海峡表面层的盐度较低，导致ITF较冷。资金支持本科生的博士后助理和研究经验。