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在四川盆地西部建立了一个由302个观测站组成的区域观测网,并进行了高精度流动重力与GPS观测,其目的是获取区域自由空气重力异常(简称重力异常)的分布特征,并对EGM2008模型在该区域的结果进行验证分析.研究区域实测的重力异常总体为负值,由西到东逐步从-160×10-5 ms-2平缓变化到-60×10-5 ms-2左右.EGM2008地球重力场模型揭示的模型重力异常较好地勾画出研究区域的总体地形分布形态,龙泉山脉以及四川盆地与青藏高原的边界皆存在明显的模型重力梯度带.研究区东南部的模型重力异常大约为-50×10-5 ms-2左右,但在龙泉山西部成都平原地区,模型重力异常则达到-120×10-5 ms-2左右.在区域观测网内绝大部分观测点上,模型与实测重力异常的差值几乎为一个常数(-10×10-5 ms-2左右),说明EGM2008地球重力场模型可较好地反映实际重力场的空间分布形态.如果配以一定数量的地面观测数据进行整体调节,EGM2008地球重力场模型就可以较真实地反映实际地球重力场.
A regional observational network consisting of 302 observatories was set up in the west of the Sichuan Basin and high-precision mobile gravity and GPS observations were carried out to obtain the distribution of free-air gravity anomalies (GRA) in the region. EGM2008 The results of the model in this region are validated and analyzed.The observed gravity anomalies in the study area are generally negative and gradually change from -160 × 10-5 ms-2 to -60 × 10-5 ms-2 gradually from west to east. The model gravity anomalies revealed by EGM2008 Earth’s Earth’s gravity anomalies well delineate the overall topography distribution patterns of the study area, and there is a clear model gravity gradient zone along the Longquan Mountains and the boundaries between the Sichuan Basin and the Qinghai-Tibet Plateau. Model gravity anomalies in the southeastern part of the study area About -50 × 10-5 ms-2, but the gravity anomaly in the Chengdu Plain of western Longquan Mountain reaches -120 × 10-5 ms-2 or so.At most observation points in the regional observation network, The difference between the model and measured gravity anomaly is almost a constant (-10 × 10-5 ms-2 or so), indicating that the earth gravity model of EGM2008 can better reflect the spatial distribution of the actual gravity field. If a certain amount of Ground Observational data overall adjustment, EGM2008 Earth’s gravity field model can truly reflect the actual Earth’s gravitational field.