当前位置: X-MOL 学术Adv. Space Res. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Lake and Reservoir Volume Variations in South America from Radar Altimetry, ICESat Laser Altimetry, and GRACE time-variable gravity
Advances in Space Research ( IF 2.6 ) Pub Date : 2020-04-01 , DOI: 10.1016/j.asr.2020.04.022
Claudia C. Carabajal , Jean-Paul Boy

Abstract Thanks to 25-years of radar altimetry measurements from TOPEX/POSEIDON, Jason 1, 2 and 3, ENVISAT and others, water level changes of major lakes and rivers can be measured regularly, remotely, with unprecedented precision, facilitating monitoring of continental water storage variations. In addition, the 18 laser altimeter measurement campaigns over 6 years by the Ice, Cloud and Land Elevation Satellite (ICESat) satellite complement these radar altimetry measurements and also validate them, expanding our monitoring capabilities. We extract derived water height estimates for various lakes in South America from radar and laser altimetry measurements. Using available imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS), we estimate time-variable surface extent of these water bodies, and together with the altimetry, we derive corresponding estimates of relative volume variations for a number of lakes and reservoirs in South America. We see good agreement between our water extent and available products, with some differences when snow covered area are present. We find good agreement between the temporal variations of lake water heights obtained from ICESat, radar altimetry, and in situ measurements, when available. Lake-dependent biases still exist, likely due to differences in reference datum, choice of geoid model, and differences in data processing schemes. The is a good agreement in volume changes obtained from imagery and the various altimetry techniques. Furthermore, using the latest one-degree global iterated mascon solutions from NASA Goddard Space Flight Center, we successfully compare them to independent volume changes assessments for these water bodies, derived from mass variations from time-variable gravity measurements from 15 years of Gravity Recovery And Climate Experiment (GRACE) observations. The agreement in water volume changes from GRACE with those from altimetry and imagery is higher for lakes in arid and semi-arid regions than on mountainous areas. GRACE volume estimates remain limited to the spatial resolution and the quality of the hydrology models used to correct for soil-moisture and snow contributions. Overall, studies like the one presented here further validate the power of leveraging these data synergies to monitor continental water storage changes from space, taking advantage of what each of the techniques has to offer. We show that water level measurements from laser and radar altimeters have similar precision, of a few centimeters over inland water bodies, and prove that GRACE global mascons allow to retrieve small lake relative volume changes, even for small bodies, thanks to their higher sensitivity to small wavelength mass variations.

中文翻译:

来自雷达测高、ICESat 激光测高和 GRACE 时变重力的南美洲湖泊和水库体积变化

摘要 得益于 TOPEX/POSEIDON、Jason 1、2、3、ENVISAT 等 25 年的雷达测高测量,主要湖泊和河流的水位变化可以定期、远程、以前所未有的精度进行测量,为大陆水监测提供便利。存储变化。此外,冰、云和陆地高程卫星 (ICESat) 卫星在 6 年内进行的 18 次激光高度计测量活动补充了这些雷达高度测量并对其进行了验证,从而扩展了我们的监测能力。我们从雷达和激光测高测量中提取出南美洲各个湖泊的水位高度估计值。使用中分辨率成像光谱仪 (MODIS) 的可用图像,我们估计这些水体随时间变化的表面范围,并与测高仪一起,我们得出了南美洲许多湖泊和水库的相对体积变化的相应估计值。我们看到我们的水域范围和可用产品之间有很好的一致性,当存在积雪区域时会有一些差异。我们发现从 ICESat、雷达高度测量和现场测量获得的湖水高度的时间变化之间有很好的一致性(如果有)。依赖湖泊的偏差仍然存在,可能是由于参考基准、大地水准面模型的选择以及数据处理方案的差异造成的。从图像和各种测高技术中获得的体积变化非常一致。此外,使用美国宇航局戈达德太空飞行中心最新的一度全局迭代 mascon 解决方案,我们成功地将它们与这些水体的独立体积变化评估进行了比较,这些变化来自于 15 年重力恢复和气候实验 (GRACE) 观测的时变重力测量的质量变化。干旱和半干旱地区湖泊的 GRACE 与高度测量和图像的水量变化一致性高于山区。GRACE 体积估计仍然限于空间分辨率和用于校正土壤水分和雪贡献的水文模型的质量。总的来说,像这里介绍的研究进一步验证了利用这些数据协同作用从太空监测大陆储水变化的能力,利用每种技术所提供的优势。
更新日期:2020-04-01
down
wechat
bug