Exploring annually laminated lake sediments for solar activity reconstructions and Sun-climate studies

气候变率的太阳强迫是气候研究中最具争议的话题之一。例如，上个世纪全球变暖是在温室气体排放增加和太阳活动频繁的背景下发生的，而1998年以来意外的温度平台期与太阳活动减少的趋势不谋而合。因此，更好地了解太阳在气候变化中的作用对于预测未来的气候发展至关重要。基于卫星的太阳活动记录太短，不能涵盖所有可用太阳变化，也不能区分人为和自然对气候系统的影响。古气候和太阳重建可以提供解决这个问题的关键。然而，冰芯中的宇宙成因放射性核素10Be和树轮中的14C的现有太阳强迫记录中的不确定性，以及缺乏足够长和分辨率足够好的具有精确年表的古气候时间序列，阻碍了此类研究。因此，为了更好地了解太阳变化对气候变化的作用，有必要探索新的方法来补充现有的太阳活动记录，并研究太阳-气候之间的联系，在太阳强迫和气候反应之间的相对时间几乎没有不确定性。据推测，精选湖泊沉积物中的10Be含量反映了太阳诱导的大气产生信号。这一提议的主要科学目标是：(1)探索中欧湖泊各种沉积物记录中10Be的潜力，将其视为新类型的太阳活动替代物，补充现有从冰芯10Be和树轮14C估计的太阳活动，以及(2)检验太阳对气候影响的假设。为了实现概述的目标，这项提议将首次整合来自不同湖泊沉积物档案的精确日期和最高每年分辨的10Be时间序列，并通过对照太阳活动仪器和气象记录以及现场监测进行校准，核实预期的太阳活动替代数据。将史无前例的太阳活动数据与来自相同湖泊的现有古气候代理数据进行比较，将使我们能够调查潜在的太阳-气候联系和相关的反馈机制，而不会出现时间尺度的不确定性。利用10Be和14C同步来自切茨霍夫斯湖和铁夫湖的预期太阳活动和古气候记录，以及来自极地冰芯和树轮的记录，将为我们提供对气候系统的领先和滞后及其与全球太阳活动的可能关系的洞察。

Solar forcing of climate variability is one of the most controversially discussed topics in climate research. For example, global warming during the last century occurred in the context of increasing greenhouse gas emission and high levels of solar activity, while the unexpected temperature plateau since 1998 coincides with a decreasing trend in solar activity. Therefore, improved knowledge of the role of the Sun in climate change is essential for projecting future climate developments. The satellite-based records of solar activity are too short to cover the full range of available solar variations and distinguish anthropogenic from natural effects on the climate system. Paleoclimate and solar reconstructions can provide a key to address this problem. However, uncertainties in available solar forcing records from cosmogenic radionuclides 10Be in ice cores and 14C in tree rings and a lack of sufficiently long and well-resolved paleoclimate time-series with precise chronologies hamper such studies so far. Therefore, for better understanding the role of solar variations on climate change it is necessary to explore new ways to complement existing solar activity records and study solar-climate linkages with virtually no uncertainties in the relative timing between solar forcing and climate responses.The potential of 10Be in annually laminated (varved) lake sediments for solar activity reconstruction is, to date, largely unexplored and existing preliminary records contain biases that can be corrected for by applying the latest analytical techniques. It is hypothesized that 10Be contents in sediments from well-chosen lakes reflect the solar induced atmospheric production signal. Main scientific objectives of this proposal are to (1) explore the potential of 10Be in the varved sediment records of Central European Lakes Czechowski and Tiefer See as new type of solar activity proxy, complement existing solar activity estimates from 10Be in ice cores and 14C in tree rings, and (2) test the hypothesis of a solar influence on climate. To reach the outlined objectives this proposal will, for the first time, integrate precisely dated and up to annually resolved 10Be time-series from varved lake sediment archives and verification of the expected solar activity proxy data by calibration against instrumental solar activity and meteorological records as well as onsite monitoring. Comparison of the unprecedented solar activity data with existing paleoclimate proxy data from the same lakes will allow us to investigate potential solar-climate links and related feedback mechanisms, without time-scale uncertainties. Synchronizing the expected solar activity and paleoclimate records from Lakes Czechowski and Tiefer See to those from polar ice cores and tree rings using 10Be and 14C will provide us insights into leads and lags of the climate system and their possible relation to solar activity worldwide.