A dataset of sub-daily C-band data, acquired with a ground-based synthetic aperture radar, has been used to study soil and vegetation dynamics during a complete growing season in a controlled agricultural test site. The data have been exploited to analyse the rate and sources of decorrelation in the scene, as well as the consequences of the observation conditions of a sub-daily satellite (with either low, medium or geosynchronous orbit): short revisit times, availability of multiple acquisitions during a single day, and shallow observations at some incidence angles. Repeat-pass coherence is found to be less affected by temporal decorrelation when the primary image is acquired during nighttime or the last hours predawn. Regarding the incidence angle, VV has increased sensitivity to certain phenological stages as the incidence angle increases. Additionally, a periodic oscillation on a sub-daily scale is observed when creating coherence time series with increasing temporal baseline. Factors which strongly contribute to these oscillations are the daily cycles of temperature, soil moisture and vegetation water dynamics.

中文翻译：

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SAR 相干幅度亚日时间序列中的去相关率和日周期


通过地面合成孔径雷达获取的次日 C 波段数据数据集已用于研究受控农业试验场整个生长季节的土壤和植被动态。这些数据已被用来分析场景中去相关的速率和来源，以及次日卫星（具有低、中或地球同步轨道）的观测条件的后果：重访时间短，多个卫星的可用性一天内的采集，以及某些入射角的浅层观察。研究发现，当在夜间或黎明前最后几个小时获取主图像时，重复通道相干性受时间去相关的影响较小。关于入射角，随着入射角的增加，VV对某些物候阶段的敏感性增加。此外，当创建具有增加的时间基线的相干时间序列时，会观察到亚日尺度的周期性振荡。强烈影响这些振荡的因素是温度、土壤湿度和植被水动态的日常循环。