Upward continuation of Dome-C airborne gravity and comparison with GOCE gradients at orbit altitude in east Antarctica
Upward continuation of Dome-C airborne gravity and comparison with GOCE gradients at orbit altitude in east Antarctica
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南极洲东部轨道高度 Dome-C 机载重力向上延续及其与 GOCE 梯度的比较
DOI：
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发表时间：
2016
影响因子：
0.9
通讯作者：
J. Bouman
中科院分区：
文献类型：
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作者：
H. Yıldız;R. Forsberg;C. Tscherning;D. Steinhage;G. Eagles;J. Bouman
2013年1月17日至22日在东南极Dome-C调查区进行了一次航空重力活动，以便为验证GOCE卫星重力梯度的实验提供数据。在对航空重力数据进行典型滤波之后，几个交叉点的交叉误差统计为11.3 mGal均方根（rms）误差，对应于8.0 mGal的rms线误差。由于飞行条件恶劣、线路短和使用的现场处理程序，这一数字相对较大。航空重力数据与GOCE RL 4球谐模型的比较证实了航空数据的质量，它们比全球模型包含更多的高频信号。首先，将航空重力数据向上延续到GOCE高度，以预测当地东北向上参考框架中的重力梯度。在这一步中，使用ITGGRACE2010S场的最小二乘配置，90阶作为参考场，从空中重力和GOCE重力梯度中减去。然后，预测的梯度旋转到梯度仪参考框架使用1级姿态四元数数据。航空重力数据的验证仅限于准确的梯度异常（TXX、TYY、TZZ和TXZ），其中GOCE梯度的长波长信息已被GOCO 03信号取代，以避免这些波长的GOCE梯度误差的污染。比较显示预测的和GOCE梯度异常TXX，TYY，TZZ和TXZ之间的标准偏差分别为9.9，11.5，11.6和10.4毫电子当量。因此，对GOCE没有观测到的南极间隙进行更精确的航空重力测量将提供更准确的梯度预测，补充GOCE在该地区的覆盖范围。
An airborne gravity campaign was carried out at the Dome-C survey area in East Antarctica between the 17th and 22nd of January 2013, in order to provide data for an experiment to validate GOCE satellite gravity gradients. After typical filtering for airborne gravity data, the cross-over error statistics for the few crossing points are 11.3 mGal root mean square (rms) error, corresponding to an rms line error of 8.0 mGal. This number is relatively large due to the rough flight conditions, short lines and field handling procedures used. Comparison of the airborne gravity data with GOCE RL4 spherical harmonic models confirmed the quality of the airborne data and that they contain more high-frequency signal than the global models. First, the airborne gravity data were upward continued to GOCE altitude to predict gravity gradients in the local North-East-Up reference frame. In this step, the least squares collocation using the ITGGRACE2010S field to degree and order 90 as reference field, which is subtracted from both the airborne gravity and GOCE gravity gradients, was applied. Then, the predicted gradients were rotated to the gradiometer reference frame using level 1 attitude quaternion data. The validation with the airborne gravity data was limited to the accurate gradient anomalies (TXX, TYY, TZZ and TXZ) where the long-wavelength information of the GOCE gradients has been replaced with GOCO03s signal to avoid contamination with GOCE gradient errors at these wavelengths. The comparison shows standard deviations between the predicted and GOCE gradient anomalies TXX, TYY, TZZ and TXZ of 9.9, 11.5, 11.6 and 10.4 mE, respectively. A more precise airborne gravity survey of the southern polar gap which is not observed by GOCE would thus provide gradient predictions at a better accuracy, complementing the GOCE coverage in this region.