Contributions of thermal expansion of monuments and nearby bedrock to observed GPS height changes

该论文表明GPS台站基岩和支撑构件的热膨胀，可以引起GPS天线明显的垂直位移。通过建立合适的模型，该文首次给出了温度变化对全球GPS台站垂直位移的影响。其研究结果表明，温度变化对GPS台站垂直位移的影响为毫米量级，最大可以达到3.9毫米。在考虑温度变化的影响后，地表流体激发与GPS观测的垂直位移更加符合。本研究可以明显改善GPS观测的垂直位移解释，能够以模块的形式添加到GPS处理软件中，具有较好的实用价值。此外，由于GPS是监测全球板块运动、地壳形变乃至全球变化的主要工具，该论文可以为以上研究提供很好的基础改正，对这些相关领域，具有重要的科学价值。

Long-term continuous Global Positioning System (GPS) observations have become an important tool for studying the various geodynamic processes. To fully study the geodynamic processes at GPS stations, the temporal movements of GPS monuments and nearby bedrock induced by thermal expansion need to be considered. In this paper, we extend a theoretical model to estimate the thermal expansions of GPS monuments and nearby bedrock for 86 globally distributed GPS stations based upon measurements of surface air temperatures. The results show that annual temperature variations are the dominant contributors for the thermal expansion of GPS monuments and nearby bedrock. The contributions of thermal expansion to GPS height changes display largely spatial variations and can reach to a few millimeters.

Paper Link：http://www.agu.org/journals/ABS/2009/2009GL038152.shtml