Borehole Climatology: Continental Energy and Climate Change

我们看到，由于对地球变暖的预测感到关切，对气候系统的研究有所增加。然而，确定气候模型的预测需要用过去的气候来验证。只有通过适当地模拟古气候，模型才能激发人们对其预测的信心。在这方面，地下温度数据对我们了解上个千年的气候做出了重大贡献。从这些数据的气候重建假设，地面空气温度耦合到地面温度，后者传播到地下的热扩散叠加在背景稳态地热场。也就是说，如果地球表面的温度发生变化，那么地面将获得（变暖）或损失（冷却）一定量的热量;这些地表能量平衡的变化会传播并记录在地下，作为背景热状况的扰动。这些地下异常的分析为地热方法重建古气候提供了基础。钻孔气候学的气候重建是独一无二的;它们的推论是对长期气候的测量，独立于气象记录。 这一研究领域一直是我过去几年工作的重点，因为它具有很大的潜力，可以帮助人们了解自然状态下的气候变化。从我提出的研究计划的结果将允许在大气-地面界面的热传递制度更完整的理解。我的长期目标是描述从大气边界层到地壳前几百米的热传递状况。这种特性对于纳入气候模型以研究气候系统，特别是了解永久冻土的演变非常有用。来自地下的热数据对于了解地球表面的能量平衡至关重要，并且还为气候模型提供了地面的长期边界条件。研究生将致力于适应最新版本的社区土地模型-CLM 4，以扩展其底部边界位置，从而允许使用地下温度来了解地面能量平衡的变化，从而了解世纪和千年时间尺度上的空气-地面界面的能量分配。我们打算进行一个千年尺度的集合模拟的全球气候模式与完全耦合的大陆组成部分。 为了使用大陆热储存作为陆地表面模型性能的衡量标准，我们将继续从世界上代表性不足的大陆地区收集更多的地热数据;例如，智利，阿根廷和巴西。我计划继续让博士和硕士学生参与这个项目的各个方面。

We are witnesses to increased research about the climate system stimulated by concerns about projections of a warmer Earth. However, ascertaining climate models' projections requires that they be validated with the climate of the past. Only by properly simulating paleoclimate, will a model inspire confidence in its projections. In this avenue, underground temperature data have contributed significantly to our understanding of the climate of the last millennium. Climate reconstructions from these data assume that surface air temperatures are coupled to ground surface temperatures, and the latter propagate to the subsurface by thermal diffusion superimposing on the background steady-state geothermal field. That is, if the temperature at the Earth's surface changes, then a quantity of heat will be gained (warming) or lost (cooling) by the ground; these changes in the energy balance at the surface propagate and are recorded underground as perturbations to the background thermal regime. Analysis of these underground anomalies provides the base of the geothermal method of paleoclimate reconstruction. Climate reconstructions from borehole climatology are unique; their inferences are a measure of long-term climate, independent from meteorological records. This area of research has been the focus of my work for the last few years because of the great potential to shed light on the understanding of climatic change in its natural state. Results from the research program I propose will allow a more complete understanding of the heat transfer regime at the atmosphere-ground interface. My long-term objectives are to characterize the heat transfer regime from the atmospheric boundary layer to the first few hundred meters of the Earth's crust. Such characterization would be very useful for incorporation into climate models to study the climate system; in particular, to understanding the evolution of permafrost. Thermal data from the subsurface are fundamental to understanding the energy balance at the Earth's surface and also provide long-term boundary conditions at the ground surface for climate models. Graduate students will work on adapting the latest version of the Community Land Model - CLM4, to extend its bottom boundary placement to allow the use underground temperatures to understand the changes in the ground surface energy balance and thus the energy partition at the air-ground interface at century and millennia time scales. We intent to perform a millennium-scale ensemble simulation of a global climate model with a fully coupled continental component. In order to use the continental heat storage as a measure of performance of land surface models, we will continue gathering additional geothermal data from underrepresented continental areas of the world; for example, Chile, Argentina and Brazil. I plan to continue involving PhD and MSc students throughout all aspects of this project.