Combination of temporal gravity variations resulting from superconducting gravimeter (SG) recordings, GRACE satellite observations and global hydrology models
Combination of temporal gravity variations resulting from superconducting gravimeter (SG) recordings, GRACE satellite observations and global hydrology models
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DOI：
10.1007/s00190-005-0014-8
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发表时间：
2006-01
影响因子：
4.4
通讯作者：
J. Neumeyer;F. Barthelmes;O. Dierks;F. Flechtner;M. Harnisch;G. Harnisch;J. Hinderer;Y. Imanishi;C. Kroner;B. Meurers;S. Petrovic;C. Reigber;R. Schmidt;P. Schwintzer;Heping Sun;H. Virtanen
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作者：
J. Neumeyer;F. Barthelmes;O. Dierks;F. Flechtner;M. Harnisch;G. Harnisch;J. Hinderer;Y. Imanishi;C. Kroner;B. Meurers;S. Petrovic;C. Reigber;R. Schmidt;P. Schwintzer;Heping Sun;H. Virtanen
重力恢复和气候实验（GRACE）得到的时间重力变化可以在μgal（10− 8 m/s2）范围内分辨，如果我们将空间分辨率限制在约1，500 km的半波长，时间分辨率限制在1个月。对于独立的验证，与地面重力测量的比较具有根本意义。为此目的，从选定的超导重力仪（SG）站组成的全球地球动力学项目（GGP）网络的数据被使用。为了比较，GRACE和SG数据集减少了相同的已知重力效应，由于地球和海洋潮汐，极潮和大气。与GRACE相比，SG还测量由于负载引起的高度变化而引起的重力变化，而卫星衍生的模型不包含这种影响。对于重力场的固体球谐分解，这种负载效应可以使用度相关的负载Love数建模，并将这种效应添加到卫星衍生模型中。在减少两个数据集的已知重力影响后，剩余部分主要可以假设代表陆地储水量的质量变化。因此，全球水文模型推导的重力变化被用来验证SG和GRACE结果。反之，水文模型可以用GRACE和SG观测的重力变化来检验。这样的比较显示了相当好的协议之间的重力变化来自SG，GRACE和水文模型，这是在其估计的误差范围内的大多数研究SG的位置。结果表明，SG重力变化（点测量）是代表一个大的区域内的准确性，如果当地的重力影响被删除。SG，GRACE和水文模型之间的差异可能会给每个数据系列的进一步调查的提示。
Gravity recovery and climate experiment (GRACE)-derived temporal gravity variations can be resolved within the μgal (10−8m/s2) range, if we restrict the spatial resolution to a half-wavelength of about 1,500 km and the temporal resolution to 1 month. For independent validations, a comparison with ground gravity measurements is of fundamental interest. For this purpose, data from selected superconducting gravimeter (SG) stations forming the Global Geodynamics Project (GGP) network are used. For comparison, GRACE and SG data sets are reduced for the same known gravity effects due to Earth and ocean tides, pole tide and atmosphere. In contrast to GRACE, the SG also measures gravity changes due to load-induced height variations, whereas the satellite-derived models do not contain this effect. For a solid spherical harmonic decomposition of the gravity field, this load effect can be modelled using degree-dependent load Love numbers, and this effect is added to the satellite-derived models. After reduction of the known gravity effects from both data sets, the remaining part can mainly be assumed to represent mass changes in terrestrial water storage. Therefore, gravity variations derived from global hydrological models are applied to verify the SG and GRACE results. Conversely, the hydrology models can be checked by gravity variations determined from GRACE and SG observations. Such a comparison shows quite a good agreement between gravity variation derived from SG, GRACE and hydrology models, which lie within their estimated error limits for most of the studied SG locations. It is shown that the SG gravity variations (point measurements) are representative for a large area within the accuracy, if local gravity effects are removed. The individual discrepancies between SG, GRACE and hydrology models may give hints for further investigations of each data series.