The past evolution of precipitation and atmospheric convection in the Western Pacific Warm Pool (WPWP) is critical for global climate changes but is under debate because of its forcing mechanisms. Here, we present a high temporal resolution (∼156 years) grain-size record of core MD01–2385 over the last 140 kyr, in offshore northern New Guinea to reveal sediment dynamics as a proxy for precipitation changes. End-member analysis revealed that a two-endmember model was optimal. The end-member 1/end-member 2 (EM1/EM2) ratio could represent the variation in grain size and exhibited significant precessional cycles changes in phase with modelled Niño 3 SST anomaly from a global climate model transient simulation. From these data, we inferred orbital fluctuations in precipitation from tropical western Pacific islands, with general precipitation peaks during the time of perihelion at the boreal autumnal equinox (midpoint from a low to high precession index), corresponding to La Niña-like conditions and vice versa. Comparisons of our new record with published precipitation records showed that orbital precipitation changes in the WPWP are mainly dominated by El Niño-Southern Oscillation-like (ENSO-like) oscillations in the precession band, while the Intertropical Convergence Zone (ITCZ) mainly controls the distribution of precipitation over a larger spatial area.

中文翻译：

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140ka以来热带太平洋岛屿颗粒大小证据揭示的轨道水文气候变化

西太平洋暖池（WPWP）降水和大气对流过去的演变对于全球气候变化至关重要，但因其强迫机制而备受争议。在这里，我们展示了新几内亚北部近海过去 140 kyr 岩心 MD01-2385 的高时间分辨率（约 156 年）粒度记录，以揭示沉积物动态作为降水变化的代理。端元分析表明两端元模型是最佳的。端元 1/端元 2 (EM1/EM2) 比率可以代表颗粒尺寸的变化，并与全球气候模型瞬态模拟中模拟的 Niño 3 海温异常表现出显着的岁差周期变化。根据这些数据，我们推断出热带西太平洋岛屿降水的轨道波动，一般降水峰值出现在北纬秋分近日点（低进动指数到高进动指数的中点），对应于类拉尼娜条件和反之。反之亦然。将我们的新记录与已发表的降水记录进行比较表明，WPWP的轨道降水变化主要由进动带中的厄尔尼诺-类南方涛动（ENSO）振荡主导，而热带辐合带（ITCZ）主要控制着进动带中的类厄尔尼诺-南方涛动（ENSO）振荡。较大空间区域的降水分布。