极地研究 ›› 2023, Vol. 35 ›› Issue (3): 371-382.DOI: 10.13679/j.jdyj.20220412

• 研究论文 • 上一篇    下一篇

基于Elmer/Ice参数约束的西南极玛丽伯德地冰盖数值模拟

杨树瑚  吕金磊  牛立杭  张云  韩彦岭  洪中华   

  1. 上海海洋大学信息学院, 上海 201306

  • 出版日期:2023-09-30 发布日期:2023-09-30
  • 通讯作者: 张云
  • 作者简介:杨树瑚, 男, 1983年生。博士, 主要从事冰盖物理过程研究。E-mail: shyang@shou.edu.cn
  • 基金资助:

    国家自然科学基金(41871325, 42176175)和国家重点研发计划(2019YFD0900805)资助

Numerical simulation of Marie Byrd Land ice sheet, West Antarctica,using constrained Elmer/Ice parameters

Yang Shuhu, Lyu Jinlei, Niu Lihang, Zhang Yun, Han Yanling, Hong Zhonghua   

  1. College of Information Technology, Shanghai Ocean University, Shanghai 201306, China

  • Online:2023-09-30 Published:2023-09-30

摘要:

西南极玛丽伯德地冰盖底部地热通量的不确定性对准确模拟其演化有着重大的影响, 探究地热通量的变化对冰盖温度场和速度场的影响具有重要意义。本文基于2021年更新的BedMachine V2中的南极冰盖底部基岩高程、表面高程数据, 添加表面温度、表面质量平衡和地热通量等边界条件, 利用Full-Stokes三维模型Elmer/Ice对西南极玛丽伯德地的部分域(76.8°S—77.3°S, 138°W—142°W)进行了静态模拟。实验通过美国冰雪中心2020年更新的MEaSUREs项目的遥感冰盖表面流速数据(MEaSUREs In-SAR-Based Antarctica Ice Velocity Map), Elmer/Ice中的冰盖底部滑动系数和格伦增强因子两个参数进行约束, 模拟得到的表面冰流速和遥感表面冰流速之间的均方根误差(RMSE)作为评价指标, 获得适合区域模拟最佳参数。当滑动系数为0.1, 格伦增强因子为0.26时取得最小RMSE(4.140 m·a1)。以此参数进行模拟, 并对地热通量进行调节, 得到了研究区域的速度场、温度场、应力场实验结果。实验结果表明, 地热通量改变时冰盖底部温度场变化较大。

关键词:

南极冰盖, 玛丽伯德地, Elmer/Ice, MEaSUREs, 表面流速

Abstract:

Remaining uncertainties considerably limit the simulation accuracy when evaluating the geothermal flux at the bottom of the Marie Byrd Land ice sheet, West Antarctica, and its temporal evolution. Investigating the influence of the geothermal flux on the ice sheet temperature and velocity field is essential. In this study, based on the bedrock elevation and surface elevation data from BedMachine Antarctica V2 updated in 2021, the surface temperature, surface mass balance and geothermal flux were added as boundary conditions, the diagnostic simulations of the part of the West Antarctic Marie Byrd Land (76.8°S–77.3°S, 138°W– 142°W) were conducted with the Full-Stokes, three-dimensional Elmer/Ice model. The parameters of the basal slip coefficient and Glen enhancement factor in Elmer/Ice were constrained by the remote sensing surface ice flow data from the MEaSUREs project (MEaSUREs In-SAR-Based Antarctica Ice Velocity Map) updated in 2020 by the National Snow and Ice Data Center. The root-mean-square error (RMSE) between the simulated and remotely-sensed surface ice flow velocities was used as an evaluation index to optimize model parameters for regional simulations. The minimum RMSE (4.140 m·a–1) was obtained for a basal friction coefficient of 0.1 and a Glen enhancement factor of 0.26. The ice-sheet velocity, temperature, and stress field were derived using these parameter values and several estimates of the geothermal flux. Experimental results show that the temperature field variations at the base of the ice sheet were greatly related to geothermal flux variations.

Key words: Antarctic ice sheet, Marie Byrd Land, Elmer/Ice, MEaSUREs, surface velocity