Tropical Climate Dynamics during the past Glacial/Interglacial Cycle in (sub)annual resolution (Cariaco Basin and Mexican Lakes)

热带辐合带的位置和哈德利环流的强度影响着中美洲的热带气候变率。我们建议的研究地点位于ITCZ位置的季节变化区域内，该位置决定了中美洲的水文循环和降雨分布。它们的范围从Cariaco盆地（委内瑞拉北部）穿过尤卡坦半岛和墨西哥中部到太平洋海岸。我们建议从那些位于降水梯度的海洋和陆地站点获得古气候数据。在高频尺度上重建热带气候和ITCZ动力学（厄尔尼诺-南方涛动- ENSO，北大西洋涛动- NAO）是理解热带在全球气候变化中的作用的关键。因此，我们建议从叠层序列中获得超高时间分辨率的数据。我们将应用基于纹层的研究、非破坏性、连续的大量沉积物测量（例如uXRF）和纹层微相分析的组合。这些数据，连同放射性核素的日期（14-C，137-Cs，210-Pb）和火山灰年代学，形成了一个强大的，基于纹层的年代学的基础。我们的数据有可能提供一个新的历史的平均状态，频率和振幅的ENSO，并解开高与低纬度之间的相互作用，迫使ITCZ动态在该地区在过去的冰期/间冰期循环（Cariaco盆地），并集中在过去的1000年（墨西哥湖泊）。我们将根据墨西哥中西部和尤卡坦半岛的社会发展讨论我们的古气候数据。

The position of the Intertropical Convergence Zone (ITCZ) and the intensity of the Hadley circulation force tropical climate variability in Central America. Our proposed study locations sit within the area of seasonal change of the ITCZ position that determines the hydrological cycle and rainfall distribution in Mesoamerica. They range from the Cariaco Basin (off N Venezuela) across Yucatan and Central Mexico to the Pazific coast. We propose to obtain paleoclimate data from those marine and terrestrial sites located across gradients of precipitation. The reconstruction of tropical climate and ITCZ dynamics on a high-frequency scale (El-Nino-Southern Oscillation - ENSO, North Atlantic Oscillation - NAO) is pivitol to understand the role of the Tropics in global climate change. Therefore, we propose to obtain data in ultra-high time resolution from laminated sequences. We will apply a combination of laminae-based studies, non-destructive, continuous bulk sediment measurements (e.g. uXRF) and varve microfacies analyses. These data, together with radionuclide dates (14-C, 137-Cs, 210-Pb) and tephrochronology, form the basis for a robust, varve-based chronology. Our data has the potential to provide a new history of mean-state, frequency, and amplitude of ENSO, and to disentangle the interplay between high versus low latitude forcing of ITCZ dynamics in the region during the past Glacial/Interglacial cycle (the Cariaco Basin) and focused on the past 1000 yr (the Mexican lakes). We will discuss our paleoclimate data in light of the societal development in west Central Mexico and Yucatan.