Multi-Mission Cross-Calibration of Satellite Altimeters: Constructing a Long-Term Data Record for Global and Regional Sea Level Change Studies
Multi-Mission Cross-Calibration of Satellite Altimeters: Constructing a Long-Term Data Record for Global and Regional Sea Level Change Studies
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DOI：
10.3390/rs6032255
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发表时间：
2014-03
期刊：
影响因子：
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通讯作者：
Wolfgang Bösch;D. Dettmering;C. Schwatke
中科院分区：
文献类型：
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作者：
Wolfgang Bösch;D. Dettmering;C. Schwatke
气候研究需要长时间的数据记录，从而延长单个遥感卫星使命的寿命。探索全球和区域海平面演变的精确卫星测高技术现已完成了20年的数据记录。必须从一系列不同的、部分重叠的高度计系统中建立一个一致的长期数据记录，这些高度计系统必须经过仔细的交叉校准。这种交叉校准是通过调整所有同时期高度计系统之间执行的一组非常大的单卫星和双星交叉差来实现的。交叉差的总集合创建了高度冗余网络，并且使得能够对所分析的所有高度表系统进行密集且相当完整的采样来对径向误差进行鲁棒的估计。采用迭代方差分量估计方法，得到不同性能高度计系统间的客观相对权重。径向误差的最终时间序列被用来估计（对于每个高度计系统）经验自协方差函数。此外，径向误差捕获相对距离偏差，并表明系统的变化，在测高卫星轨道的地理中心。该程序有可能估计所有高度计系统的地理相关的平均误差，这是不是在所有可见的单卫星交叉差异，但直接映射到平均海面的估计。
Climate studies require long data records extending the lifetime of a single remote sensing satellite mission. Precise satellite altimetry exploring global and regional evolution of the sea level has now completed a two decade data record. A consistent long-term data record has to be constructed from a sequence of different, partly overlapping altimeter systems which have to be carefully cross-calibrated. This cross-calibration is realized globally by adjusting an extremely large set of single- and dual-satellite crossover differences performed between all contemporaneous altimeter systems. The total set of crossover differences creates a highly redundant network and enables a robust estimate of radial errors with a dense and rather complete sampling for all altimeter systems analyzed. An iterative variance component estimation is applied to obtain an objective relative weighting between altimeter systems with different performance. The final time series of radial errors is taken to estimate (for each of the altimeter systems) an empirical auto-covariance function. Moreover, the radial errors capture relative range biases and indicate systematic variations in the geo-centering of altimeter satellite orbits. The procedure has the potential to estimate for all altimeter systems the geographically correlated mean errors which is not at all visible in single-satellite crossover differences but maps directly to estimates of the mean sea surface.