Ice-water interactions in the sublacial Lake Vostok, Antarctica: numerical simulations

在国际冰年期间，对像沃斯托克湖这样的南极冰下湖泊的调查是SCARSALE倡议的中心目标。在这个项目中，收集了古气候记录分析、冰下湖泊准入方面的技术进步，以及对冰下环境中的水文/湖泊条件的调查。我们的项目对这些主题的建模工作做出了贡献，并产生了对可能的湖泊条件和环境对环境和组成变化的敏感性的估计。在延迟启动后，湖泊模型的技术发展，如对流态的混合参数的调查，已经完成了其主要部分。关于地热通量和湖泊含盐量的敏感性研究表明，该湖的流动模式相当稳定，只在一定范围内变化。只有比冰芯数据估计的盐度高两倍的盐度才会改变环流模式和基本物质平衡。这些结果和正在进行的其他数值实验将导致建立一个标准模型，该模型将在请求的项目阶段用于调查由于南极湖泊冰下连通而产生的排水对湖泊系统的影响、湖泊的同位素组成、可能的生物地球化学湖泊条件以及基本物质平衡对上覆冰盖动力学的影响。

The investigation of subglacial Antarctic lakes like Lake Vostok is a central goal of the SCARSALE initiative during IPY. Within this program paleo-climate record analyses, technological advances in subglacial lake access, and investigations on hydrological/limnological conditions in subglacial environments are gathered. Our project contributes with modelling efforts to these topics and yields estimates of probable lake conditions and sensitivities of the environment to changes in their setting and composition. After a delay in getting started, technical developments of the lake model, such as investigations on mixing parametrisation on the flow regime have been completed to its major part. Sensitivity studies regarding the geothermal heat flux and the salt content of the lake reveal a quite stable flow pattern, which only varies within certain limits. Only a twofold increase in salinity than estimated from ice core data yields changes hi circulation pattern and basal mass balance. These results and additional numerical experiments in progress will lead to a standard model setup, which will in the requested project phase be used to investigate the impact of drainage water on the lake system due to subglacial connection of Antarctic lakes, the isotopic composition of the lake, probable bio-geochemical lake conditions, and the impact of the basal mass balance on the overlying ice sheet dynamics.