Assessing ocean-forced, marine-terminating glacier change in Greenland during climatic warm periods and its impact on marine productivity (Kang-Glac)

评估气候温暖时期格陵兰岛受海洋驱动、海洋终止的冰川变化及其对海洋生产力的影响 (Kang-Glac)

• 批准号: NE/V006630/1
• 负责人: Christian Maerz
• 金额: $ 18.07万
• 依托单位: University of Bonn
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FV006630%2F1
• 关键词: Assessing; ocean; forced; marine; terminating

The receding Greenland Ice Sheet (GrIS) is now the largest contributor to global sea-level rise. A major driving force behind this recession is the encroachment of warm ocean water through fjords to the faces of marine-terminating outlet glaciers (MTOGs) that drain the ice sheet. Satellite data confirm that these glaciers have thinned, accelerated and retreated over the past few decades, but with significant temporal and spatial variability. Despite this information, our ability to predict how, and at what rate, the ice sheet will respond to future warming is made difficult by a lack of direct observations from these remote and often ice-infested areas and by the limited time-series of existing datasets. Constraining Greenland's likely decay trajectory is necessary to evaluate policy options with regard to its contribution to sea level rise. However, the wider effects of this decay also encompass the marine environments bordering the landmass. Increasing the supply of freshwater to these areas (as meltwater and icebergs) alters circulation patterns and impacts North Atlantic weather systems, including those affecting the UK. It also brings nutrients to offshore areas that promote marine productivity, which in turn has the potential to draw down more atmospheric CO2 and bury organic carbon in fjord and shelf sediments. To date, these processes have not been quantified and we need to improve our understanding of this negative feedback to climate change before it can be incorporated into predictive models.One way to determine which ice-ocean-marine ecosystem scenarios are analogues for future warming scenarios is to extend the record of modern observations back over the last 11,700 years of the Holocene using proxies from marine sediment cores. A few records of 20th Century iceberg calving and warm water encroachment exist around Greenland but there are no comprehensive, coupled records of past glacier change, ocean warming and marine productivity for earlier periods. Here, we propose to generate these long-term records for the Holocene era for a key location in SE Greenland (Kangerlussuaq Fjord) calibrated by observations of the present-day system over three annual cycles. We will then use numerical modelling constrained by our new data to test how the Greenland Ice Sheet responded to climatic warming during the Holocene, particularly during the Holocene Thermal Maximum when summer temperatures were analogous to those predicted for 2100.We will acquire a full suite of oceanographic, biological and geological observations during a 6-week multidisciplinary cruise to SE Greenland on the UK's new polar research vessel, the RRS Sir David Attenborough, making full use of its state-of-the-art capabilities as a logistical platform. We will use cruise datasets to determine modern interactions between warm water inflows and glacial meltwater outflows, and to quantify marine productivity, sedimentation and nutrient cycling. At the same time, we will collect long and short marine-sediment cores and terrestrial rock samples to constrain past changes in glacier dynamics and derive coupled proxy records of ocean temperatures and carbon burial/storage. To do this, we will calibrate the sediment-core signals with our modern observations using an anchored mooring and repeat observations.

后退的格陵兰冰盖（GRIS）现在是全球海平面上升的最大贡献者。这次衰退背后的主要动力是通过峡湾侵占了温暖的海水，到达耗尽冰盖的海洋末端出口冰川（MTOG）的脸。卫星数据证实，在过去的几十年中，这些冰川已经变薄，加速和退缩，但具有显着的时间和空间变化。尽管有这些信息，但由于缺乏从这些遥远且经常受到冰期侵入的领域以及现有数据集的有限时间序列的直接观察，我们很难预测冰盖如何以及以什么速度响应未来变暖的能力。限制格陵兰的可能衰减轨迹对于评估其对海平面上升的贡献的政策选择是必要的。但是，这种衰变的更广泛影响也包括与地产接壤的海洋环境。增加对这些地区（融水和冰山）的淡水供应改变了循环模式，并影响北大西洋天气系统，包括影响英国的系统。它还为促进海洋生产率的近海地区带来了养分，这反过来又有可能吸收更多大气的二氧化碳，并在峡湾和架子沉积物中掩埋有机碳。迄今为止，这些过程尚未得到量化，我们需要提高对气候变化的负面反馈的理解，然后才能将其纳入预测模型。一种确定哪种冰山海洋生态系统情景的一种方法是对未来变暖情景的类似方法，即在过去11,700年的现代观察中延长了使用Marine Serescene proiment Seresciens cores cores cores cores cores cores core的记录。格陵兰岛周围存在了20世纪冰山产犊和温水侵占的一些记录，但没有较早的冰川变化，海洋变暖和海洋生产力的全面，耦合记录。在这里，我们建议在全新世（SE Greenland（Kangerlussuaq Fjord））中为全新世时代生成这些长期记录，并通过三个年度周期对当今系统的观察进行了观察。然后，我们将使用受新数据约束的数值建模来测试格陵兰冰盖在全新世期间对气候变暖的反应，尤其是在全新世的最大热量期间，当夏季温度类似于预测的2100年的夏季温度类似。我们将获得一群全新的海洋学，生物学和地球上的海洋学研究，在一个6周的众所周知的众所周知，众所周知，众所周知，众所周知，这一新的是新的绿地，这一新的是新的绿地。 Attenborough，充分利用其最先进的功能作为后勤平台。我们将使用Cruise数据集来确定温水流入和冰川融水流出之间的现代相互作用，并量化海洋生产率，沉积和养分循环。同时，我们将收集长而短的海洋补充核心和地面岩石样品，以限制冰川动力学的过去变化，并得出海洋温度和碳埋葬/存储的耦合代理记录。为此，我们将使用锚定系泊和重复观测来通过我们的现代观察来校准沉积物核心信号。