Long-wavelength lithospheric magnetic field of China
Long-wavelength lithospheric magnetic field of China
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DOI：
10.1093/gji/ggaa490
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发表时间：
2020-12
影响因子：
2.8
通讯作者：
Yi Jiang;R. Holme;S. Xiong;Yong Jiang;Yan Feng;Hai Yang
中科院分区：
文献类型：
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作者：
Yi Jiang;R. Holme;S. Xiong;Yong Jiang;Yan Feng;Hai Yang
结合CHAOS-6、MF 7、LCS-1和NGDC 720等卫星模型提供的长波长信息，以及97 994个短波长分辨率为10 km × 10 km的高质量航磁数据，提出了中国岩石圈场的新区域模型CLAS。该模型估计使用的全球球谐函数中心在中国的耗尽的基础上。确定CLAS模型包括高达400的谐波度。虽然为了平衡两个数据集的一致性，损失了航磁数据的部分精度，但结果表明，CLAS模型与卫星模型在低阶项有很高的相关性（相关度> 0.9），而在高阶项有更高的功效，反映了中国大陆岩石圈场的更多特征。改善的例子包括长白山、四川盆地和青藏高原。CLAS模型与中国航磁数据在波长低至100 km（对应球谐度n = 400）的范围内具有良好的一致性（相干度> 0.9），填补了卫星模型与航磁数据之间的空白。与100公里处的航磁数据进行比较，结果吻合良好（相关性> 0.95）。CLAS模型和航磁数据之间的残差仍然很大（rms > 70 nT），但大多数失配来自较短的波长场，模型无法在高达400的度数下拟合;这种失配可以通过增加模型度数来减少。我们提供了一个地质的例子，包括卫星数据可以改变地质结论，可以从磁信息。然而，这两个数据集并不完全一致，未来的模型应该从重新分析航磁数据及其线水准测量开始，以确保与卫星模型的一致性。
We present new regional models, denoted CLAS, of the Chinese lithospheric field, combining the long-wavelength information provided by satellite-derived models: CHAOS-6, MF7, LCS-1 and NGDC720, and an extremely high-quality compilation of 97 994 aeromagnetic survey data with 10 km × 10 km resolution for shorter wavelength. The models are estimated using a depleted basis of global spherical harmonic functions centred on China. CLAS models are determined include harmonic degrees up to 400. Although some accuracy of aeromagnetic data is lost in order to balance the consistent of two data sets, the results show that CLAS models have a high correlation with the satellite models at low-degree terms (degree correlation > 0.9) but with more power at high-degree terms, reflecting more features of the lithospheric field in continental China. Examples of improvement include Changbai mountains, Sichuan Basin and Qinghai–Tibet Plateau. CLAS models have good agreement (coherence > 0.9) with Chinese aeromagnetic data at wavelength down to about 100 km (corresponding to spherical harmonic degree n = 400), filling the usual gap between satellite models and aeromagnetic data. Comparison with aeromagnetic data filtered at 100 km gives good agreement (correlation > 0.95). The residuals between CLAS models and aeromagnetic data are still large (rms > 70 nT), but with most of misfits arising from shorter wavelength fields that the model cannot fit at degree up to 400; such misfit could be reduced by increasing the model degree. We provide a geological example of how the inclusion of satellite data can change the geological conclusions that can be drawn from the magnetic information. However, the two data sets are not completely consistent, future models should start from a reanalysis of the aeromagnetic data and its line levelling to ensure consistency with the satellite model.