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- 实验方案
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Performance Assessment of ICESat-2 Laser Altimeter Data for Water-Level Measurement Over Lakes and Reservoirs in China
摘要： Although the Advanced Topographic Laser Altimeter System (ATLAS) onboard the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) was primarily designed for glacier and sea-ice measurement, it can also be applied to monitor lake surface height (LSH). However, its performance in monitoring lakes/reservoirs has rarely been assessed. Here, we report an accuracy evaluation of the ICESat-2 laser altimetry data over 30 reservoirs in China using gauge data. To show its characteristics in large-scale lake monitoring, we also applied an advanced radar altimeter SARAL (Satellite for ARgos and ALtika) and the first laser altimeter ICESat (Ice, Cloud and land Elevation Satellite) to investigate all lakes and reservoirs (>10 km2) in China. We found that the ICESat-2 has a greatly improved altimetric capability, and the relative altimetric error was 0.06 m, while the relative altimetric error was 0.25 m for SARAL. Compared with SARAL and ICESat data, the ICESat-2 data had the lowest measurement uncertainty (the standard deviation of along-track heights; 0.02 m vs. 0.07 m and 0.17 m), the greatest temporal frequency (3.43 vs. 1.35 and 1.48 times per year), and the second greatest lake coverage (636 vs. 814 and 311 lakes). The precise altimetric profiles derived from the ICESat-2 data indicate that most lakes (90% of 636 lakes) are quasi-horizontal (measurement uncertainty <0.05 m), and special methods are needed for mountainous lakes or shallow lakes to extract precise LSHs.
关键词： Water level,Validation,ICESat-2,ICESat,SARAL,Lake and reservoir
更新于2025-09-16 10:30:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Comparision of Retrackers’ Performances Over Inland Water Bodies
摘要： The water level of inland water bodies plays an essential role in water balance management. Satellite altimeters can play an important role in monitoring water level, namely in remotely access places. However, satellite altimeters are normally designed to monitor homogeneous surfaces such as oceans or ice sheets, which results in poor performance over small inland water bodies because of the land contamination contribution in the returned waveforms. This paper presents three specialized algorithms or retrackers to retrieve water levels from radar altimeter data over inland water bodies dedicated to restricting the land contamination of the signal. The performances of the waveform portion selection method and the three retrackers which are the threshold retracker, Offset Center of Gravity (OCOG) retracker and 2-step analytical retracker are compared. Time series of water level results are retrieved over water bodies in Ebre river basin (Catalunya, Spain) and Lake Volta (West Africa). The standard deviation for 2-step analytical retracker combined with the waveform portion selection ranges from 0.02m to 0.05m, for OCOG retracker ranges from 0.07m to 0.13m, and for threshold retracker, it ranges from 0.05m to 0.1m over Lake Volta. The results show good accuracy with the in situ measurements over lake Ebre and Ribarroja reservoir with RMSE about 0.44m and 0.18m separately. All performances of the three retrackers are compared with the onboard retracker as well.
关键词： retracker,Water level,waveform,altimeter
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Remote Estimation of Water Storage Variation of Lakes in Tibetan Plateau Over the Past 20 Years
摘要： Changes in water storage of the lakes at the Tibetan Plateau are regarded as one of the most critical indicators of regional hydrological response to climate change. Different to the conventional hydrological approaches, in this study, we investigate the storage change of four lakes basing on a conceptual lake storage model and the most recent (2001-2016) available satellite observation that cover the lakes. The water surface areas and water levels are derived from MODIS and LEGOS altimetry data, respectively. Based on the regression function between water level and lake area, the net water budgets of the four lakes are estimated for the period. The results show that the storage of Ziling Co rose the fastest at the rate of 8.24 billion m3/a in the past decades, and the rising rate of Qinghai lake has also reached 4.5billion m3/a. The Ngoring Lake which located in the same region with Qinghai Lake changed fluctuatingly, but the water storage has risen 4.9 billion m3 from 2001 to 2016. The water storage of Dogaicoring QC increased steadily at the rate of 1.2 billion m3/a.
关键词： Lake water level – area curve,Water storage changes,Remote Sensing
更新于2025-09-04 15:30:14
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Combining Multispectral Imagery with in situ Topographic Data Reveals Complex Water Level Variation in China’s Largest Freshwater Lake
摘要： Lake level variation is an important hydrological indicator of water balance, biodiversity and climate change in drainage basins. This paper illustrates the use of moderate-resolution imaging spectroadiometer (MODIS) data to characterize complex water level variation in Poyang Lake, the largest freshwater lake in China. MODIS data were used in conjunction with in situ topographic data, otherwise known as the land-water contact method, to investigate the potential of this hybrid water level spatiotemporal variability measurement technique. An error analysis was conducted to assess the derived water level relative to gauge data. Validation results demonstrated that the land-water contact method can satisfactorily capture spatial patterns and seasonal variations in water level fluctuations. The correlation coefficient ranged from 0.684 to 0.835, the root-mean-square-error from 0.79 m–1.09 m, and the mean absolute bias error from 0.65 m to 0.86 m for five main gauge stations surrounding the lake. Additionally, seasonal and interannual variations in the lake’s water level were revealed in the MODIS-based results. These results indicate that the land-water contact method has the potential to be applied in mapping water level changes in Poyang Lake. This study not only provides a foundation for basic hydrological and ecological studies, but is also valuable for the conservation and management of water resources over gauge-sparse regions in Poyang Lake.
关键词： Poyang Lake,water level,in situ topographic data,spatiotemporal variation,MODIS
更新于2025-09-04 15:30:14