The role of regional feedbacks in glacial inception on Baffin Island: the interaction of ice flow and meteorology
The role of regional feedbacks in glacial inception on Baffin Island: the interaction of ice flow and meteorology
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DOI：
10.5194/cp-14-1441-2018
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发表时间：
2018-10
影响因子：
4.3
通讯作者：
L. Birch;T. Cronin;E. Tziperman
中科院分区：
文献类型：
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作者：
L. Birch;T. Cronin;E. Tziperman
抽象。在过去的80万年里，100 kyr冰河时代主导了地球的气候，地质证据表明最后一次冰川始于巴芬岛的山脉。目前，国家的最先进的全球气候模式（GCM）有困难的模拟冰川的开始，可能部分是由于其粗糙的水平分辨率和忽略冰流动力学在一些模式。我们试图解决的作用，区域反馈在巴芬岛的初始问题异步耦合的天气研究和预报（WRF）模型，配置为一个高分辨率的内部域巴芬和外部域，包括北美大部分地区，冰流模型使用浅冰近似。质量平衡是根据WRF模拟计算的，并用于驱动冰模型，冰模型更新冰的范围和海拔，然后作为下一次WRF运行的输入。我们使用1986年的大气边界条件，对应于一个相对寒冷的夏天，并与115千年日照驱动器的区域WRF配置。最初，冰在山上的冰川上积累，推动下坡的冰流，扩大了冰盖的大小。然而，大气和冰模型的持续迭代揭示了巴芬岛冰盖的停滞，这是由于冰盖边缘温度升高而导致的融化。这种变暖是由区域环流的变化引起的，这些变化是由于冰的生长而引起的海拔变化所造成的。因此，冰高度和大气环流之间的稳定反馈防止了完全起始的发生。
Abstract. Over the past 0.8 million years, 100 kyr ice ages have dominated Earth's climate with geological evidence suggesting the last glacial inception began in the mountains of Baffin Island. Currently, state-of-the-art global climate models (GCMs) have difficulty simulating glacial inception, possibly due in part to their coarse horizontal resolution and the neglect of ice flow dynamics in some models. We attempt to address the role of regional feedbacks in the initial inception problem on Baffin Island by asynchronously coupling the Weather Research and Forecast (WRF) model, configured as a high-resolution inner domain over Baffin and an outer domain incorporating much of North America, to an ice flow model using the shallow ice approximation. The mass balance is calculated from WRF simulations and used to drive the ice model, which updates the ice extent and elevation, that then serve as inputs to the next WRF run. We drive the regional WRF configuration using atmospheric boundary conditions from 1986 that correspond to a relatively cold summer, and with 115 kya insolation. Initially, ice accumulates on mountain glaciers, driving downslope ice flow which expands the size of the ice caps. However, continued iterations of the atmosphere and ice models reveal a stagnation of the ice sheet on Baffin Island, driven by melting due to warmer temperatures at the margins of the ice caps. This warming is caused by changes in the regional circulation that are forced by elevation changes due to the ice growth. A stabilizing feedback between ice elevation and atmospheric circulation thus prevents full inception from occurring.