Simulation of the time-variable gravity field by means of coupled geophysical models
Simulation of the time-variable gravity field by means of coupled geophysical models
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DOI：
10.5194/essd-3-19-2011
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发表时间：
2011-10
影响因子：
11.4
通讯作者：
T. Gruber;J. Bamber;M. Bierkens;H. Dobslaw;M. Murböck;Maik Thomas;L. V. Beek;T. Dam;L. Vermeerse
中科院分区：
文献类型：
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作者：
T. Gruber;J. Bamber;M. Bierkens;H. Dobslaw;M. Murböck;Maik Thomas;L. V. Beek;T. Dam;L. Vermeerse
抽象的。时变重力场反映了地球系统质量分布的变化，是了解地球变化的关键参数之一。质量变化是由地球表面内部、表面或上方的质量重新分布或地球内部的地球物理过程引起的。美国/德国GRACE卫星使命于2002年开始提供了第一批地球重力场月变化观测数据。这一使命仍在为科学界提供有价值的信息。然而，由于GRACE已经超过了它的预期寿命，地球科学界目前正在寻找后续任务，以维持GRACE开始的长期气候变化序列。近年来，已就科学要求和技术可行性进行了若干研究。这些研究需要时变重力场的真实模型，以便对卫星及其仪器的灵敏度进行模拟研究。这是欧洲航天局（欧空局）发起一项关于“通过卫星监测地球系统中物质分布和传输的单个来源并建立模型”的研究的主要原因。这项跨学科研究的目标是基于耦合地球物理模型创建尽可能真实的模拟时变重力场，这些模型可用于受控环境中的模拟过程。为此，使用了全球大气、海洋、大陆水文和冰模型。通过在整个模型中使用一致的强迫，并通过包括地球系统的不同域之间的水流来进行耦合。此外，重力场的变化，由于固体地球的过程，如连续的冰川均衡调整（GIA）和突发地震的同震和震后信号进行了模拟。所有单独的模型结果被合并并转换为重力场球谐级数，这是通常用于描述地球全球重力场的量。这项研究的结果是一个12年的时间序列的6小时时变重力场球谐函数的度和阶数为180对应的全球空间分辨率为1度的纬度和经度。在本文中，我们概述了输入数据集和这些数据集相结合的过程中的时间重力场变化的相干模型。由此产生的时间序列被用于一些后续研究，并提供给任何感兴趣的人。
Abstract. Time variable gravity fields, reflecting variations of mass distribution in the system Earth is one of the key parameters to understand the changing Earth. Mass variations are caused either by redistribution of mass in, on or above the Earth's surface or by geophysical processes in the Earth's interior. The first set of observations of monthly variations of the Earth gravity field was provided by the US/German GRACE satellite mission beginning in 2002. This mission is still providing valuable information to the science community. However, as GRACE has outlived its expected lifetime, the geoscience community is currently seeking successor missions in order to maintain the long time series of climate change that was begun by GRACE. Several studies on science requirements and technical feasibility have been conducted in the recent years. These studies required a realistic model of the time variable gravity field in order to perform simulation studies on sensitivity of satellites and their instrumentation. This was the primary reason for the European Space Agency (ESA) to initiate a study on ''Monitoring and Modelling individual Sources of Mass Distribution and Transport in the Earth System by Means of Satellites''. The goal of this interdisciplinary study was to create as realistic as possible simulated time variable gravity fields based on coupled geophysical models, which could be used in the simulation processes in a controlled environment. For this purpose global atmosphere, ocean, continental hydrology and ice models were used. The coupling was performed by using consistent forcing throughout the models and by including water flow between the different domains of the Earth system. In addition gravity field changes due to solid Earth processes like continuous glacial isostatic adjustment (GIA) and a sudden earthquake with co-seismic and post-seismic signals were modelled. All individual model results were combined and converted to gravity field spherical harmonic series, which is the quantity commonly used to describe the Earth's global gravity field. The result of this study is a twelve-year time-series of 6-hourly time variable gravity field spherical harmonics up to degree and order 180 corresponding to a global spatial resolution of 1 degree in latitude and longitude. In this paper, we outline the input data sets and the process of combining these data sets into a coherent model of temporal gravity field changes. The resulting time series was used in some follow-on studies and is available to anybody interested.