Geosat高度计数据处理与南海重力异常反演精度评价
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摘要
卫星测高技术对于观测全球范围内全天候、重复准确的海洋信息具有极为重要的意义。利用高精度的观测值反演重力异常是获得海洋重力异常的重要途径之一。观测值的精度与反演重力异常的精度评价直接影响着高精度的海洋重力异常的确定。
本文针对目前交叉点平差计算过程复杂及误差模型不完善的缺点,改进了交叉点平差方法中的误差模型。该误差模型不仅考虑了径向轨道误差,同时考虑了多种系统误差干扰的综合效应,既包含了误差的线性变化部分,也包含了误差周期性变化的部分,同时又根据每条轨道的数据点数不同,选用不同参数的误差模型,并利用条件平差方法进行交叉点平差。计算结果表明,该方法计算过程简单,不存在秩亏问题,而且平差精度与传统方法相当,提高了结果的稳定性和可靠性。可见基于改进误差模型的条件平差方法更为实用。
目前利用实际船测数据评价反演重力异常精度都只是简单给出均方根误差,并没有针对重力异常分布特点进行评价。为了更详细的评价南海部分区域重力异常反演精度,以及探讨能否用卫星测高反演重力异常填补实际船测重力异常数据的空白区的问题,本文采用了总体对比和分级分区对比方法评价了反演重力异常的精度。总体对比结果表明卫星测高数据反演的重力异常精度为7.42mGal,反演精度较高,结果可信。高精度的重力异常数据大多集中在-30mGal~30mGal之间,根据重力异常的定义可见该分级对比结果正符合实际情况,表明地球重力场本身对卫星测高的精度有着较大的影响。选择中沙群岛空白区以南和以北两个区域进行分区对比,两区域的反演精度均高于整个区域的反演精度,表明在中沙群岛附近卫星测高反演的精度较低,用卫星测高反演重力异常填补实际船测重力异常空白区的可行性有待进一步探讨。
The satellite altimetry technique has very important meanings for observing all-weather, duplicative and accurate marine information in the worldwide. Using high-precision observations of inversing gravity anomaly is one of important channels to obtain marine gravity anomaly. The accuracy of observed values and the accuracy assessment of inversing gravity anomaly affect directly the determination of high-precision the marine gravity anomalies.
Focusing on the shortcomings of complexity in current crossover adjustment process and imperfect of error models, the error model has been improved in the crossover adjustment method in this thesis. This error model is considering the radial orbit error while taking a variety of composite effects produced by the interruption of systematic errors into account. It includes not only the linear part of the error but also the periodical part of it. At the same time, according to the different data points on each track, the error model of different parameters is chosen, and crossover adjustment is done by the use of conditional adjustment. The results show that the calculation process of this method is simple without rank deficient, and the accuracy of the adjustment is similar with the results obtained from traditional methods. It improves the stability and reliability of the results. It can be seen that conditional adjustment based on improving error models is more practical.
At present, accuracy assessment on the inversion of gravity anomalies with the boat test data is just to suggest the root mean square error simply, without considering the characteristics of gravity anomaly distribution. In order to get more detailed assessment on inversion precision of gravity anomalies in some regions of South Sea, and discuss whether satellite altimetry inversing gravity anomaly can fill the blank areas where the actual boat test data can’t be measured or not, this thesis evaluates the precision of inversing gravity anomalies with the comparative methods of overall method and zoning classification. The overall comparative results indicate that the accuracy of inversing gravity anomalies measured by the satellite altimetry is 7.42 , a high precision. The result is credible. High-precision gravity anomaly data mostly is concentrated from -30 mGal to 30 mGal . The comparative results of the classification coincide with the actual condition according to the definition of gravity anomaly. It shows that the earth’s gravity field itself has a great impact on the accuracy of satellite altimetry. The south and the north areas of Zhongsha Islands blank area are selected to compare partitively, and the inversion accuracy of the two areas is higher than that of the whole area. It shows that the precision inversed by satellite altimetry is lower near Zhongsha Islands, so the feasibility of filling the blank areas which the actual boat test data can’t measure with satellite altimetry inversing gravity anomaly is to be further explored.
本文针对目前交叉点平差计算过程复杂及误差模型不完善的缺点,改进了交叉点平差方法中的误差模型。该误差模型不仅考虑了径向轨道误差,同时考虑了多种系统误差干扰的综合效应,既包含了误差的线性变化部分,也包含了误差周期性变化的部分,同时又根据每条轨道的数据点数不同,选用不同参数的误差模型,并利用条件平差方法进行交叉点平差。计算结果表明,该方法计算过程简单,不存在秩亏问题,而且平差精度与传统方法相当,提高了结果的稳定性和可靠性。可见基于改进误差模型的条件平差方法更为实用。
目前利用实际船测数据评价反演重力异常精度都只是简单给出均方根误差,并没有针对重力异常分布特点进行评价。为了更详细的评价南海部分区域重力异常反演精度,以及探讨能否用卫星测高反演重力异常填补实际船测重力异常数据的空白区的问题,本文采用了总体对比和分级分区对比方法评价了反演重力异常的精度。总体对比结果表明卫星测高数据反演的重力异常精度为7.42mGal,反演精度较高,结果可信。高精度的重力异常数据大多集中在-30mGal~30mGal之间,根据重力异常的定义可见该分级对比结果正符合实际情况,表明地球重力场本身对卫星测高的精度有着较大的影响。选择中沙群岛空白区以南和以北两个区域进行分区对比,两区域的反演精度均高于整个区域的反演精度,表明在中沙群岛附近卫星测高反演的精度较低,用卫星测高反演重力异常填补实际船测重力异常空白区的可行性有待进一步探讨。
The satellite altimetry technique has very important meanings for observing all-weather, duplicative and accurate marine information in the worldwide. Using high-precision observations of inversing gravity anomaly is one of important channels to obtain marine gravity anomaly. The accuracy of observed values and the accuracy assessment of inversing gravity anomaly affect directly the determination of high-precision the marine gravity anomalies.
Focusing on the shortcomings of complexity in current crossover adjustment process and imperfect of error models, the error model has been improved in the crossover adjustment method in this thesis. This error model is considering the radial orbit error while taking a variety of composite effects produced by the interruption of systematic errors into account. It includes not only the linear part of the error but also the periodical part of it. At the same time, according to the different data points on each track, the error model of different parameters is chosen, and crossover adjustment is done by the use of conditional adjustment. The results show that the calculation process of this method is simple without rank deficient, and the accuracy of the adjustment is similar with the results obtained from traditional methods. It improves the stability and reliability of the results. It can be seen that conditional adjustment based on improving error models is more practical.
At present, accuracy assessment on the inversion of gravity anomalies with the boat test data is just to suggest the root mean square error simply, without considering the characteristics of gravity anomaly distribution. In order to get more detailed assessment on inversion precision of gravity anomalies in some regions of South Sea, and discuss whether satellite altimetry inversing gravity anomaly can fill the blank areas where the actual boat test data can’t be measured or not, this thesis evaluates the precision of inversing gravity anomalies with the comparative methods of overall method and zoning classification. The overall comparative results indicate that the accuracy of inversing gravity anomalies measured by the satellite altimetry is 7.42 , a high precision. The result is credible. High-precision gravity anomaly data mostly is concentrated from -30 mGal to 30 mGal . The comparative results of the classification coincide with the actual condition according to the definition of gravity anomaly. It shows that the earth’s gravity field itself has a great impact on the accuracy of satellite altimetry. The south and the north areas of Zhongsha Islands blank area are selected to compare partitively, and the inversion accuracy of the two areas is higher than that of the whole area. It shows that the precision inversed by satellite altimetry is lower near Zhongsha Islands, so the feasibility of filling the blank areas which the actual boat test data can’t measure with satellite altimetry inversing gravity anomaly is to be further explored.
引文
[1]王虎彪.用卫星测高和船测重力资料联合反演海洋重力场.中国科学院测量与地球物理研究所,硕士论文,2005.
[2]翟国君,黄谟涛,谢锡君等.卫星测高数据处理的理论与方法[M].测绘出版社.2000.
[3] Shum, CK, et al. The accuracy and applications of satellite altimetry[J]. Geophys. J. Int,1995,121:321-336.
[4]王海瑛.中国近海卫星测高数据处理与应用研究.中国科学院测量与地球物理研究所,博士论文,1999.
[5] Sandwell D T. Marine gravity anomaly from Geosat and ERS-1 satellite altimetry[J]. Journal of geophysical research, 1997,102(B5):10039-10054.
[6] Wessel,P.and A.B.Watts. On the accuracy of marine gravity measurements[J]. J.Geophys.Res.,1988,93:393-413.
[7] Rapp R H. Determination of geoid undulation and gravity anomalies form seasat altimeter data[J]. J.Geophys.Res., 1983,88(C3):1552-1562.
[8]王海瑛,王广运.卫星测高数据的沿轨迹重力异常反演法及其应用[J].测绘学报,2001,1(30):21-26.
[9]李建成,宁津生,陈俊勇等.中国海域大地水准面和重力异常的确定[J].测绘学报,2003,2(32):114-119.
[10]黄谟涛,翟国君等.利用卫星测高数据反演海洋重力异常研究[J].测绘学报,2001,2(30):179-184.
[11]纪永刚.神舟四号高度计有效波高反演及功能评价.中国海洋大学,硕士论文,2003.
[12]王广运,王海瑛,许国昌.卫星测高原理[M].科学出版社,1995.
[13] Lee-lueng Fu, Anny Cazenave. Satellite altimetry and earth sciences[M]. Academic press. 2001.
[14] NOAA.User manual: The geosat altimeter JGM-3 GDRs on CD-ROM.NOAA, 1997.
[15]姜卫平.卫星测高技术在大地测量学中的应用.武汉大学,博士论文,2001.
[16]刘传勇,黄谟涛,欧阳永忠等.卫星测高正常点海面高度计算方法研究[J].海洋测绘,2005,25(6):4-8.
[17]彭富清,夏哲仁,张瑞华等.计算测高卫星的正常点及其平均海面高[J].地球物理学进展,2004,19(2):438-441.
[18] Robert E. Cheney, James G.Marsh. Global mesoscale variability from collinear tracks of seasat altimeter data[J]. Journal of geophysical research, 1983,88(C7):4343-4354.
[19]刘传勇,暴景阳,黄谟涛等.验后平差方法在Geosat/ERM卫星测高数据处理中的应用[J].海洋测绘,2008,28(1):5-8.
[20]黄谟涛,翟国君,欧阳永忠等.海洋重力测量误差补偿两步处理法[J].武汉大学学报,2002,27(3):251-255.
[21]黄谟涛,王瑞,翟国君等.多代卫星测高数据联合平差及重力场反演[J].武汉大学学报,2007,32(11):988-993.
[22] Huang Motao. Marine gravity surveying line system adjustment[J]. Journal of Geodesy, 1995,(70):158-165.
[23] Van Gysen. H. Local crossover analysis of exactly repeating satellite altimeter data[J]. Journal of Geodesy, 1997,(72):31-43.
[24] Kim M.C. Theory of satellite ground-track crossovers[J]. Journal of Geodesy, 1997,(71):749-767.
[25]张卡,张书毕,盛业华.秩亏自由网的双重条件平差[J].测绘通报,2004,(8):4-6.
[26]黄谟涛,翟国君,欧阳永忠等.海洋磁力测量误差补偿技术研究[J].武汉大学学报,2006,31(7):603-606.
[27]樊月波.联合卫星测高数据确定大地水准面的应用和研究.信息工程大学,硕士论文, 2002.
[28]陈俊勇,李建成,晁定波.用T/P测高数据确定中国海域及其邻域的海面高及海面地形[J].武汉测绘科技大学学报,1995,20(4):321-326.
[29]张有广.神州四号飞船高度计数据处理及功能评价.中国科学院研究生院,博士论文,2004.
[30] Sandwell D T. A detailed view of the south pacific geoid from satellite altimetry[J]. J. Geophys. Res.,1984(B2):1089-1104.
[31] Olgiati.A, Balmino G. Gravity anomalies from satellite altimetry: comparison between computation via geoid heights and via deflections of the vertical[J]. Bulletin Geodesique, 1995,(69):252-260.
[32]邢乐林,李建成,刘晓玲.ENVISAT测高卫星沿轨大地水准面梯度的海洋垂线偏差法研究[J].测绘科学,2006,31(5):48-49.
[33] Tziavos I.N.,Andritsanos V.D.. Improvements in the computation of deflection of the vertical by fft[J]. Phys. Chem. Earth, 1998,23(1):71-75.
[34]张有广,张杰,纪永刚.TOPEX/Poseidon卫星测高的垂线偏差修正[J].海洋科学进展,2004,22:187-191.
[35]彭富清,张瑞华,石磐等.基于卫星测高的海域大地水准面[J].地球物理学报,2003,46(4):462-466.
[36]王虎彪,王勇,陆洋.联合多种测高数据确定中国边缘海及全球海域的垂线偏差[J].武汉大学学报,2007,32(9):770-773.
[37]邓凯亮,暴景阳,章传银等.联合多代卫星测高数据建立中国近海垂线偏差模型[J].海洋测绘,2008,28(3):15-17.
[38] Hwang C. Inverse vening meinesz formula and deflection-geoid formula: applications to the predictions of gravity and geoid over the south china sea[J]. Journal of Geodesy, 1998,(72):304-312.
[39]王海瑛,王广运.中国近海卫星测高数据的重力异常反演-沿轨迹垂线偏差反演法[J].高技术通讯,2000:46-49.
[40] David T. Sandwell. Antarctic marine gravity field from high-density satellite altimetry[J]. Geophys. J. Int., 1992,(109):437-448.
[41] Hwang Cheinway. Fast algorithm for the formation of normal equations in a least-squares spherical harmonic analysis by fft[J]. manuscripta geodaetica, 1993,(18):46-52.
[42]李建成,宁津生,陈俊勇等.联合TOPEX/Poseidon,ERS2和Geosat卫星测高资料确定中国近海重力异常.测绘学报,2001,30(3):197-202.
[43]张瑞华,彭富清,刘光明.利用卫星测高资料确定全球海洋重力场.海洋测绘,2002,22(5):7-11.
[44]王虎彪,王勇,陆洋等.用卫星测高和船测重力资料联合反演海洋重力异常[J].大地测量与地球动力学,2005,25(1):81-85.
[45]黄谟涛,翟国君,欧阳永忠等.利用多代卫星测高数据反演海洋重力场.测绘科学,2006,31(6):37-39.
[2]翟国君,黄谟涛,谢锡君等.卫星测高数据处理的理论与方法[M].测绘出版社.2000.
[3] Shum, CK, et al. The accuracy and applications of satellite altimetry[J]. Geophys. J. Int,1995,121:321-336.
[4]王海瑛.中国近海卫星测高数据处理与应用研究.中国科学院测量与地球物理研究所,博士论文,1999.
[5] Sandwell D T. Marine gravity anomaly from Geosat and ERS-1 satellite altimetry[J]. Journal of geophysical research, 1997,102(B5):10039-10054.
[6] Wessel,P.and A.B.Watts. On the accuracy of marine gravity measurements[J]. J.Geophys.Res.,1988,93:393-413.
[7] Rapp R H. Determination of geoid undulation and gravity anomalies form seasat altimeter data[J]. J.Geophys.Res., 1983,88(C3):1552-1562.
[8]王海瑛,王广运.卫星测高数据的沿轨迹重力异常反演法及其应用[J].测绘学报,2001,1(30):21-26.
[9]李建成,宁津生,陈俊勇等.中国海域大地水准面和重力异常的确定[J].测绘学报,2003,2(32):114-119.
[10]黄谟涛,翟国君等.利用卫星测高数据反演海洋重力异常研究[J].测绘学报,2001,2(30):179-184.
[11]纪永刚.神舟四号高度计有效波高反演及功能评价.中国海洋大学,硕士论文,2003.
[12]王广运,王海瑛,许国昌.卫星测高原理[M].科学出版社,1995.
[13] Lee-lueng Fu, Anny Cazenave. Satellite altimetry and earth sciences[M]. Academic press. 2001.
[14] NOAA.User manual: The geosat altimeter JGM-3 GDRs on CD-ROM.NOAA, 1997.
[15]姜卫平.卫星测高技术在大地测量学中的应用.武汉大学,博士论文,2001.
[16]刘传勇,黄谟涛,欧阳永忠等.卫星测高正常点海面高度计算方法研究[J].海洋测绘,2005,25(6):4-8.
[17]彭富清,夏哲仁,张瑞华等.计算测高卫星的正常点及其平均海面高[J].地球物理学进展,2004,19(2):438-441.
[18] Robert E. Cheney, James G.Marsh. Global mesoscale variability from collinear tracks of seasat altimeter data[J]. Journal of geophysical research, 1983,88(C7):4343-4354.
[19]刘传勇,暴景阳,黄谟涛等.验后平差方法在Geosat/ERM卫星测高数据处理中的应用[J].海洋测绘,2008,28(1):5-8.
[20]黄谟涛,翟国君,欧阳永忠等.海洋重力测量误差补偿两步处理法[J].武汉大学学报,2002,27(3):251-255.
[21]黄谟涛,王瑞,翟国君等.多代卫星测高数据联合平差及重力场反演[J].武汉大学学报,2007,32(11):988-993.
[22] Huang Motao. Marine gravity surveying line system adjustment[J]. Journal of Geodesy, 1995,(70):158-165.
[23] Van Gysen. H. Local crossover analysis of exactly repeating satellite altimeter data[J]. Journal of Geodesy, 1997,(72):31-43.
[24] Kim M.C. Theory of satellite ground-track crossovers[J]. Journal of Geodesy, 1997,(71):749-767.
[25]张卡,张书毕,盛业华.秩亏自由网的双重条件平差[J].测绘通报,2004,(8):4-6.
[26]黄谟涛,翟国君,欧阳永忠等.海洋磁力测量误差补偿技术研究[J].武汉大学学报,2006,31(7):603-606.
[27]樊月波.联合卫星测高数据确定大地水准面的应用和研究.信息工程大学,硕士论文, 2002.
[28]陈俊勇,李建成,晁定波.用T/P测高数据确定中国海域及其邻域的海面高及海面地形[J].武汉测绘科技大学学报,1995,20(4):321-326.
[29]张有广.神州四号飞船高度计数据处理及功能评价.中国科学院研究生院,博士论文,2004.
[30] Sandwell D T. A detailed view of the south pacific geoid from satellite altimetry[J]. J. Geophys. Res.,1984(B2):1089-1104.
[31] Olgiati.A, Balmino G. Gravity anomalies from satellite altimetry: comparison between computation via geoid heights and via deflections of the vertical[J]. Bulletin Geodesique, 1995,(69):252-260.
[32]邢乐林,李建成,刘晓玲.ENVISAT测高卫星沿轨大地水准面梯度的海洋垂线偏差法研究[J].测绘科学,2006,31(5):48-49.
[33] Tziavos I.N.,Andritsanos V.D.. Improvements in the computation of deflection of the vertical by fft[J]. Phys. Chem. Earth, 1998,23(1):71-75.
[34]张有广,张杰,纪永刚.TOPEX/Poseidon卫星测高的垂线偏差修正[J].海洋科学进展,2004,22:187-191.
[35]彭富清,张瑞华,石磐等.基于卫星测高的海域大地水准面[J].地球物理学报,2003,46(4):462-466.
[36]王虎彪,王勇,陆洋.联合多种测高数据确定中国边缘海及全球海域的垂线偏差[J].武汉大学学报,2007,32(9):770-773.
[37]邓凯亮,暴景阳,章传银等.联合多代卫星测高数据建立中国近海垂线偏差模型[J].海洋测绘,2008,28(3):15-17.
[38] Hwang C. Inverse vening meinesz formula and deflection-geoid formula: applications to the predictions of gravity and geoid over the south china sea[J]. Journal of Geodesy, 1998,(72):304-312.
[39]王海瑛,王广运.中国近海卫星测高数据的重力异常反演-沿轨迹垂线偏差反演法[J].高技术通讯,2000:46-49.
[40] David T. Sandwell. Antarctic marine gravity field from high-density satellite altimetry[J]. Geophys. J. Int., 1992,(109):437-448.
[41] Hwang Cheinway. Fast algorithm for the formation of normal equations in a least-squares spherical harmonic analysis by fft[J]. manuscripta geodaetica, 1993,(18):46-52.
[42]李建成,宁津生,陈俊勇等.联合TOPEX/Poseidon,ERS2和Geosat卫星测高资料确定中国近海重力异常.测绘学报,2001,30(3):197-202.
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