Early detection and comprehensive monitoring of inland water algal blooms is fundamental to their effective management and mitigation of potential ecosystem and public health impacts. With the spatial and temporal limitations of in situ sampling, algal bloom monitoring capabilities have been enhanced greatly by advancements in satellite Earth Observation (EO). Three turbid, eutrophic Canadian lakes (Lake Winnipeg (LW); Lake Erie (LE); Lake of the Woods (LoW)) have been the focus of Environment and Climate Change Canada (ECCC) research and monitoring initiatives due to concerns over persistent degraded water quality from recurring algal blooms. ECCC’s EOLakeWatch was developed to deliver a suite of useful, easily interpretable, and accessible EO-derived products to support algal bloom monitoring on these three lakes. Algal bloom indices, describing bloom spatial extent, intensity, duration, and severity were derived using the European Space Agency’s OLCI (Ocean and Land Colour Instrument) sensor for observations from 2016 to present and its predecessor MERIS (Medium Resolution Imaging Spectrometer) for 2002 to 2011. Results document widespread blooms on each lake, with maximum spatial extent of 21,641 km² (representing 88.1% of the lake area) on LW, 3070 km² (79.5%) on LoW and 5257 km² (19.7%) on LE. Bloom intensity showed seasonal and inter-annual variability on all three lakes, with a suggestion that LoW may be responding to reduced nutrient loads with a recent decrease in bloom intensity. Annual bloom duration on LW and LoW was on average 44 and 47 days respectively, while on LE blooms were significantly shorter in duration at an average of 24 days. Variance among the derived bloom indices was shown to be significant (i.e. the most extensive bloom was not necessarily the longest or most intensive), demonstrating the need for the indices to be used collectively, or for any single comprehensive bloom indicator to capture the variability of all individual metrics. Bloom indices are processed in a fully automated operational capacity, distributed in near-real-time through a web portal and collated into end-user-friendly annual algal bloom reports for each lake. These products go a long way to address existing monitoring gaps, delivering prompt, consistent measures of lake-wide algal bloom conditions required to provide stakeholders with early warning of bloom risks, identify areas of potential concern, quantify spatio-temporal trends, further understand bloom dynamics and drivers, as well as guide and determine the effectiveness of implemented management actions.

早期发现和全面监测内陆水域藻华是对其有效管理和缓解潜在生态系统和公共健康影响的基础。由于原位采样的时空限制，通过卫星地球观测（EO）的进步，藻华监测功能得到了极大的增强。由于担心持续退化，加拿大的三个浑浊，富营养化的湖泊（温尼伯湖（LW）；伊利湖（LE）；伍兹湖（LoW））成为加拿大环境与气候变化（ECCC）研究和监测计划的重点藻类反复繁殖的水质。ECCC的EOLakeWatch的开发目的是提供一套有用的，易于解释且易于获取的EO衍生产品，以支持这三个湖泊上的藻华监测。藻华指数LW上²（占湖泊面积的88.1％），LoW上3070 km ²（79.5％）和5257 km ²（19.7％）在LE上。盛开强度显示了所有三个湖泊的季节和年际变化，这表明低水位可能是由于近期盛开强度降低而对养分减少造成的。LW和LoW上的年开花时间分别平均为44天和47天，而LE上的年开花时间平均为24天，显着缩短。结果表明，衍生的盛开指数之间的差异很显着（即，最广泛的盛开不一定是最长或最密集的），这表明需要对指数进行集体使用，或者需要使用任何单一的综合盛开指标来捕捉玉米的变异性。所有单独的指标。Bloom索引以完全自动化的操作能力进行处理，通过网络门户近乎实时地分发，并整理成最终用户友好的每个湖泊的年度藻华报告。这些产品可以有效解决现有的监控漏洞，提供及时，一致的措施来衡量全湖范围内的藻华状况，从而为利益相关者提供华霜风险的预警，确定潜在的关注领域，量化时空趋势，进一步了解华藻动态和驱动因素，以及指导和确定已实施管理措施的有效性。