Changes in the Indonesian Throughflow during the past 2000 yr
Changes in the Indonesian Throughflow during the past 2000 yr
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DOI：
10.1130/g31421.1
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发表时间：
2011-01-01
期刊：
影响因子：
5.8
通讯作者：
Stott, Lowell
中科院分区：
文献类型：
--
作者：
Newton, Alicia;Thunell, Robert;Stott, Lowell
印度尼西亚通流（ITF）是印度洋和太平洋之间地表和温跃层水交换的唯一低纬度通道；80%的ITF水域经过望加锡海峡。通过海峡的热量和盐的通量部分取决于海峡南北两端的密度差。本文利用从望加锡海峡南北两端采集的两个沉积物岩心中采集的浮游有孔虫Globigerinoides橡胶的Mg/Ca和稳定氧同位素组成来重建过去2000年的地表水温度（SST）、海面盐度（SSS）和海水密度变率。与中世纪太阳极大期和中世纪暖期（约1000-700年前）相吻合。700年后，两个地点的海温和海温均下降，并在300 - 100年前的小冰期达到最小值。然而，在过去的2000年里，两个站点的海温和海温变化幅度明显不同，特别是在2000 - 900年之间。这导致望加锡海峡南北密度梯度的变化。具体来说，大约2000年至800年前的时间间隔主要表现为海峡北端相对于南端密度较高，这表明从太平洋到印度洋的热通量减少。这与先前的研究一致，表明这段时间间隔也标志着频繁的厄尔尼诺现象。相反，从大约800年到300年前，包括小冰期，海峡南端的表面密度较高的时期频繁出现，表明印度洋的热通量增强。
The Indonesian Throughflow (ITF) is the only low-latitude conduit for exchange of surface and thermocline waters between the Indian and Pacific Oceans; 80% of the ITF waters pass through the Makassar Strait. The flux of heat and salt through the strait is, in part, a function of the density difference between its southern and northern ends. Here the Mg/Ca and stable oxygen isotope compositions of the planktonic foraminifer Globigerinoides ruber sampled from two sediment cores collected at the northern and southern ends of the Makassar Strait are used to reconstruct surface-water temperature (SST), sea-surface salinity (SSS), and seawater density variability over the past 2000 yr. Maximum SST and SSS occurred at both sites between 850 and 700 yr ago, coinciding with the Medieval Solar Maximum and Medieval Warm Period (ca. 1000-700 yr ago). SST and SSS declined at both locations after 700 yr ago and reached minimum values during the Little Ice Age, between 300 and 100 yr ago. However, the magnitude of SST and SSS change over the past 2000 yr was distinctly different between the two sites, especially during the period between 2000 and 900 yr ago. This led to changes in the south to north density gradient within the Makassar Strait. Specifically, the time interval from ca. 2000 to 800 yr ago was marked predominantly by higher densities at the northern end relative to the southern end of the strait, suggesting reduced heat flux from the Pacific to the Indian Ocean. This is consistent with previous work showing that this time interval was also marked by frequent El Nino conditions. Conversely, the period from ca. 800 to 300 yr ago, including the LIA, was marked by frequent periods when surface density was higher at the southern end of the strait, indicative of enhanced heat flux to the Indian Ocean.