Semiquantitative Estimates of Rainfall Variability During the 8.2 kyr Event in California Using Speleothem Calcium Isotope Ratios
Semiquantitative Estimates of Rainfall Variability During the 8.2 kyr Event in California Using Speleothem Calcium Isotope Ratios
复制标题
利用岩石层钙同位素比值对加州8.2 kyr事件降水变异性的半定量估计
DOI：
10.1029/2020gl089154
复制
发表时间：
2021-02-16
影响因子：
5.2
通讯作者：
Oster, Jessica L.
中科院分区：
文献类型：
--
作者：
de Wet, Cameron B.;Erhardt, Andrea M.;Oster, Jessica L.
从一个快速增长的石笋多重代理记录揭示了可变的水文气候在加州海岸跨越8.2 kyr事件和前兆事件可能造成的最初排水的冰川湖阿加西。使用洞穴沉积物三角洲Ca-44，我们开发了第一个半定量估计的古降雨变率为加州通过校准与现代气候和洞穴环境的测量。我们发现，8.2 kyr事件期间的降雨变化幅度接近最近（1950-2019年）可观察到的多年变化，而前兆事件期间的变化幅度可能超过了这个范围。此外，我们观察到其他情况下的几十年变化的幅度相媲美的前兆事件在记录。我们的工作表明，洞穴沉积物钙同位素比值是一个强大的半定量手段重建paleorainfall，虽然许多因素必须在每个洞穴系统应用这种方法之前进行评估。
A multiproxy record from a fast-growing stalagmite reveals variable hydroclimate on the California coast across the 8.2 kyr event and a precursor event likely caused by initial drainage of proglacial Lake Agassiz. Using speleothem delta Ca-44, we develop the first semiquantitative estimates of paleorainfall variability for California through calibration with measurements of the modern climate and cave environment. We find that the magnitude of rainfall variability during the 8.2 kyr event approached the multiyear variability observable in the recent past (1950-2019) and the magnitude of variability during the precursor event likely exceeded this range. Additionally, we observe other instances of multidecadal variability comparable in magnitude to the precursor event during the record. Our work suggests that speleothem calcium isotope ratios are a powerful semiquantitative means to reconstruct paleorainfall, although numerous factors must be assessed in each cave system before applying this approach.