Tropical Pacific temperature seasonality around Meltwater Pulse-1A from IODP Expedition 310 corals

来自 IODP Expedition 310 珊瑚的 Meltwater Pulse-1A 周围热带太平洋温度季节性

• 批准号: 408139156
• 负责人: Dr. Thomas Felis
• 金额: --
• 依托单位: Department of Earth Science
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/408139156?language=en
• 关键词: Tropical; Pacific; temperature; seasonality; around

Seasonality plays a fundamental role in Earth’s climate, but the evolution of the annual cycle of temperature at Earth’s surface is not well constrained in the past - in particular for the tropical ocean, a key player in global climate dynamics. The amplitude of the temperature annual cycle is thought to be modulated by Earth’s orbital variations on longer timescales. Seasonality is of considerable importance to improved model projections of future climate change through retrospective simulations of past climates, but quantifiable evidence of the annual cycle of temperature from geological archives is sparse. Fossil shallow-water corals provide a unique but relatively rare archive of sea surface temperature seasonality for the tropical ocean and can be precisely dated by the U-series method. Emerging coral work from the Atlantic suggests that temperature seasonality of the tropical surface ocean is controlled mainly by orbital insolation changes during interglacials, even during periods of substantial climate perturbations and abrupt sea-level rise. However, comparable information for glacials and deglaciations is still lacking. Here we suggest reconstructing and quantifying tropical Pacific temperature seasonality during the last deglaciation with a specific focus on meltwater pulse (MWP) 1A (~14.5 kyr ago), by analysing geochemical proxies in the skeletons of fossil shallow-water corals (Porites) drilled by IODP Expedition 310 ’Tahiti Sea Level’. Supplemented by a new collection of modern Tahiti Porites corals recovered from the vicinity of the Expedition 310 drill sites serving as present-day benchmark to robustly assess the uncertainties in our reconstructions, we intend to test the hypotheses if tropical Pacific temperature seasonality is controlled mainly by orbital insolation changes during (1) the last deglaciation and, in particular, (2) during MWP-1A, a period characterized by abrupt sea-level rise and climate change and substantial climate perturbations. Our anticipated coral results will provide rare proxy data for comparisons with state-of-the-art climate model simulations, e.g., those of the German Climate Modeling Initiative PALMOD "From the Last Interglacial to the Anthropocene – Modeling a Complete Glacial Cycle", and will contribute to an improved understanding of the seasonal response of tropical Pacific climate variability to abrupt perturbations on glacial-interglacial timescales. This is of high relevance for improved projections of future tropical Pacific climate variability and its global teleconnections on society-relevant timescales.

季节性在地球气候中起着重要作用，但地球表面温度年周期的演变在过去并没有受到很好的限制-特别是对于热带海洋，这是全球气候动力学的关键角色。温度年周期的幅度被认为是由地球轨道变化在较长的时间尺度上调制的。季节性对于通过对过去气候的回顾性模拟来改进未来气候变化的模型预测具有相当重要的意义，但是来自地质档案的温度年度循环的可量化证据很少。化石浅水珊瑚提供了一个独特的，但相对罕见的档案海洋表面温度季节性的热带海洋，可以精确地定年的U系列方法。来自大西洋的新兴珊瑚研究表明，热带表层海洋的温度季节性主要受间冰期期间轨道日射变化的控制，即使是在重大气候扰动和海平面突然上升期间。然而，冰川和冰川消退的可比信息仍然缺乏。在这里，我们建议重建和量化热带太平洋温度的季节性在最后一次冰消期，特别关注融水脉冲（MWP）1A（~14.5 kyr前），通过分析地球化学代理的化石浅水珊瑚（滨珊瑚）的骨骼钻由IODP远征310“塔希提海平面”。补充的现代塔希提岛滨珊瑚从附近的探险310钻井现场恢复作为当今的基准，以有力地评估我们的重建的不确定性，我们打算测试的假设，如果热带太平洋温度季节性主要是由轨道日照变化控制（1）最后一次冰消期，特别是（2）在MWP-1A，这一时期的特点是海平面突然上升，气候变化和重大的气候扰动。我们预期的珊瑚结果将提供罕见的替代数据，用于与最先进的气候模型模拟进行比较，例如，德国气候模拟倡议PALMOD的“从末次间冰期到人类世-模拟一个完整的冰川周期”项目，将有助于更好地了解热带太平洋气候变异对冰川-间冰期时间尺度上突然扰动的季节性反应。这对于改进对未来热带太平洋气候变率及其在社会相关时间尺度上的全球遥相关的预测具有重要意义。