Abstract Prolonged periods of wet soil conditions, when present during critical crop development stages, can significantly elevate the risk of some crop diseases. Wet soils in fields of flowering canola are a concern with respect to the development of sclerotinia as this pathogen feeds on the petals of the canola flower. As such, determining if canola is in bloom during periods of high moisture is important in deciding whether to take action to mitigate this disease. In this paper, RADARSAT-2 quad polarization and TerraSAR-X dual polarization Synthetic Aperture Radar (SAR) data were used with a novel dynamic filtering framework to estimate canola growth stages. In this process, a new crop growth stage indicator was developed and SAR polarimetric parameters sensitive to changes in phenology were identified. Model development used multi-year SAR satellite and field data for one site in Manitoba, Canada. The crop growth estimator was then tested on unseen data from three sites, one in each of Canada's Prairie provinces. This independent validation established that the growth estimator was able to accurately determine canola growth stage and date of flowering with high accuracy. Correlation coefficients (r-values) between observed and estimated phenology ranged from 0.91 to 0.96. Given that this method performed well on test data from other sites and years, this approach could be widely adopted for monitoring the development of canola over extended regions.

中文翻译：

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使用合成孔径雷达估算油菜物候

摘要 如果在作物生长关键阶段出现长期潮湿的土壤条件，会显着增加某些作物病害的风险。开花油菜田中的潮湿土壤是核盘菌发育的一个问题，因为这种病原体以油菜花的花瓣为食。因此，确定油菜籽在高湿度时期是否开花对于决定是否采取行动减轻这种疾病很重要。在本文中，RADARSAT-2 四极化和 TerraSAR-X 双极化合成孔径雷达 (SAR) 数据与新型动态滤波框架一起使用，以估计油菜籽生长阶段。在此过程中，开发了一种新的作物生长阶段指标，并确定了对物候变化敏感的 SAR 极化参数。模型开发使用了加拿大马尼托巴省一个站点的多年 SAR 卫星和现场数据。然后对来自三个地点的未见数据测试了作物生长估算器，每个地点位于加拿大的草原省份。这一独立验证表明，生长估计器能够以高精度准确确定油菜籽生长阶段和开花日期。观察到的和估计的物候学之间的相关系数（r 值）介于 0.91 到 0.96 之间。鉴于这种方法在其他地点和年份的测试数据上表现良好，因此可以广泛采用这种方法来监测扩展区域的油菜籽发育。这一独立验证表明，生长估计器能够以高精度准确确定油菜籽生长阶段和开花日期。观察到的和估计的物候学之间的相关系数（r 值）介于 0.91 到 0.96 之间。鉴于这种方法在其他地点和年份的测试数据上表现良好，因此可以广泛采用这种方法来监测扩展区域的油菜籽发育。这一独立验证表明，生长估计器能够以高精度准确确定油菜籽生长阶段和开花日期。观察到的和估计的物候学之间的相关系数（r 值）介于 0.91 到 0.96 之间。鉴于这种方法在其他地点和年份的测试数据上表现良好，因此可以广泛采用这种方法来监测扩展区域的油菜籽发育。