Satellite altimetry is increasingly considered as a valuable source of information in many hydrological and hydraulic applications. However, the accuracy of different sensors adopted for monitoring the water level from satellite and the limited temporal resolution that characterizes each sensor (i.e. revisit time most of time varying from 10 to 35 days; 369 days in case of CryoSat mission) still hamper their common use. Recently introduced multi-mission (MM) densified time series might represent a possible alternative to ensure higher spatial and temporal coverage. Though, a comparison of the potential of different altimetry products, including MM series, for hydrodynamic model calibration is still missing. This study attempts to fill this gap investigating how available altimetry series perform over a stretch of the Po River (nearly 140 km across Northern Italy) in calibrating a quasi-2D model built with detailed topographic information. Specifically, objectives are manifold: i) to provide a comparison of satellite altimetry products available to the research community and commonly used in hydraulic modelling (Envisat, Envisat extended mission, ERS-2, TOPEX/Poseidon, SARAL/AltiKa, Jason-2, Jason-3, Sentinel 3A, Sentinel 3B and CryoSat); ii) to evaluate the performance of MM satellite series in calibrating a hydraulic model relative to single-mission series; and iii) to investigate the importance of the number of observations (series length) for each mission.

Results of the model calibration depict a general improvement of satellite performance over time, moving from the oldest to more recent missions, with the exception of Envisat extended series. In general, Jason-2, Sentinel 3A and Sentinel 3B outperform other series both in terms of calibration error and number of measurements required to achieve a reliable calibration. MM series provide errors larger than those obtained from original single-mission time series considered with their overall length, but they provide more reliable calibrations than altimetric time series with low sampling rate (i.e., Envisat, Envisat extended, and SARAL/AltiKa) or those that cover very short periods (e.g. altimetry series limited to 20–40 months in length). The analysis offers additional insights into the possible use of altimetry series in hydrodynamic applications, providing a comparison of different original products and showing the potential, as well as limitations, offered by MM series.

在许多水文和水利应用中，卫星测高法越来越被认为是有价值的信息来源。但是，用于监测卫星水位的不同传感器的精度以及表征每个传感器的有限时间分辨率（即，大多数时间的重访时间从10到35天不等；如果是CryoSat任务，则为369天）仍然妨碍了它们的通用性。采用。最近引入的多任务（MM）致密时间序列可能代表了确保更高的空间和时间覆盖范围的一种可能选择。但是，仍然缺少对包括MM系列在内的不同测高产品进行水动力模型校准的潜力的比较。这项研究试图弥补这一空白，研究在校准带有详细地形信息的准二维模型时，可用的测高序列如何在一段波河（横跨意大利北部近140公里）上表现良好。具体来说，目标是多种多样的：i）比较研究团体可用的和通常用于水力建模的卫星测高仪产品（Envisat，Envisat扩展任务，ERS-2，TOPEX / Poseidon，SARAL / AltiKa，Jason-2， Jason-3，Sentinel 3A，Sentinel 3B和CryoSat）；ii）评估MM卫星系列在校准与单任务系列有关的水力模型方面的性能；iii）调查每个任务的观测数量（系列长度）的重要性。具体来说，目标是多种多样的：i）比较研究团体可用的和通常用于水力建模的卫星测高仪产品（Envisat，Envisat扩展任务，ERS-2，TOPEX / Poseidon，SARAL / AltiKa，Jason-2， Jason-3，Sentinel 3A，Sentinel 3B和CryoSat）；ii）评估MM卫星系列在校准与单任务系列有关的水力模型方面的性能；iii）调查每个任务的观测数量（系列长度）的重要性。具体来说，目标是多种多样的：i）比较研究团体可用的和通常用于水力建模的卫星测高仪产品（Envisat，Envisat扩展任务，ERS-2，TOPEX / Poseidon，SARAL / AltiKa，Jason-2， Jason-3，Sentinel 3A，Sentinel 3B和CryoSat）；ii）评估MM卫星系列在校准与单任务系列有关的水力模型方面的性能；iii）调查每个任务的观测数量（系列长度）的重要性。ii）评估MM卫星系列在校准与单任务系列有关的水力模型方面的性能；iii）调查每个任务的观测数量（系列长度）的重要性。ii）评估MM卫星系列在校准与单任务系列有关的水力模型方面的性能；iii）调查每个任务的观测数量（系列长度）的重要性。

模型校准的结果表明，随着时间的推移，卫星性能总体上得到了改善，从最早的任务转移到了最近的任务，但Envisat扩展系列除外。通常，Jason-2，Sentinel 3A和Sentinel 3B在校准误差和实现可靠校准所需的测量次数方面均胜过其他系列。MM系列提供的误差比从其整体长度考虑的原始单次任务时间序列获得的误差大，但与低采样率的时间序列（即Envisat，Envisat Extended和SARAL / AltiKa）或那些具有较低采样率的时间序列相比，它们提供了更可靠的校准涵盖了非常短的时间（例如，测高系列的时长限制为20-40个月）。该分析为在水动力应用中可能使用高度计系列提供了更多的见解，