Effects of uncertainties in the geothermal heat flux distribution on the Greenland Ice Sheet: An assessment of existing heat flow models
Effects of uncertainties in the geothermal heat flux distribution on the Greenland Ice Sheet: An assessment of existing heat flow models
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地热热通量分布的不确定性对格陵兰冰盖的影响：现有热流模型的评估
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发表时间：
2012
期刊：
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通讯作者：
Maik Thomas
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作者：
I. Rogozhina;J. Hagedoorn;Z. Martinec;Z. Martinec;K. Fleming;O. Souček;R. Greve;Maik Thomas
[1]本研究分析了格陵兰冰盖（GIS）模型中的不确定性，所产生的不良约束地热通量（GHF）分布。在动态GIS建模的背景下，我们考虑以下问题：（一）现有的GHF模型的GIS建模研究之间的差异的意义是什么？(ii)由GHF模式控制的模拟GIS与观测数据的一致性如何？(iii)GHF和气候强迫的不确定性对观测到的和模拟的现今GIS之间的不匹配的相对贡献是什么？古气候模拟的结果表明，在GHF模型的差异有重大影响的历史和由此产生的当今状态的GIS。冰盖模型控制的任何这些GHF强迫再现所观察到的GIS状态，只有有限的程度，并未能再现在格陵兰岛南部测量的地形或低基底温度。相比之下，一个简单的空间均匀的GHF强迫控制的模拟结果在一个相当好的适合与观测，提出了问题的三个GHF模型在GIS建模的框架内使用。敏感性试验表明，格陵兰中部的模拟和测量温度之间的不匹配主要是由于不准确的GHF和威斯康星州降水强迫。然而，格陵兰南部冰盖模式的失败主要是由于地表温度强迫的不准确性和所有GHF模式普遍高估的GHF值造成的。
[1] This study analyzes the uncertainties in the models of the Greenland Ice Sheet (GIS) that arise from ill-constrained geothermal heat flux (GHF) distribution. Within the context of dynamic GIS modeling, we consider the following questions: (i) What is the significance of the differences between the existing GHF models for the GIS modeling studies? (ii) How well does the modeled GIS controlled by the GHF models agree with the observational data? (iii) What are the relative contributions of uncertainties in GHF and climate forcing to the misfit between the observed and modeled present-day GIS? The results of paleoclimatic simulations suggest that differences in the GHF models have a major effect on the history and resulting present-day state of the GIS. The ice sheet model controlled by any of these GHF forcings reproduces the observed GIS state to only a limited degree and fails to reproduce either the topography or the low basal temperatures measured in southern Greenland. By contrast, the simulation controlled by a simple spatially uniform GHF forcing results in a considerably better fit with the observations, raising questions about the use of the three GHF models within the framework of GIS modeling. Sensitivity tests reveal that the misfit between the modeled and measured temperatures in central Greenland is mostly due to inaccurate GHF and Wisconsin precipitation forcings. The failure of the ice sheet model in southern Greenland, however, is mainly caused by inaccuracies in the surface temperature forcing and the generally overestimated GHF values suggested by all GHF models.