The Cooperative Institute for Great Lakes Research (CIGLR) in collaboration with the Great Lakes Observing System and National Oceanic and Atmospheric Administration, Great Lakes Environmental Research Laboratory (NOAA GLERL) deployed an autonomous underwater glider in southern Lake Michigan several times per year between 2012 and 2019 to collect offshore (>30 m depth) limnological measurements, including temperature, photosynthetically active radiation (beginning during 2015), and chlorophyll-α fluorescence. From these data, we calculated mixed layer depth, several measures of light penetration (diffuse attenuation coefficient, first optical depth, euphotic zone depth), and depth of the subsurface chlorophyll-α maxima. During summer, mean offshore mixed layer depth was typically 10–15 m, K_d for PAR was 0.1–0.17 m⁻¹, first optical depth was 6–9 m, euphotic zone depth was 35–40 m, and depth of subsurface chlorophyll-α maxima was 30–35 m. We also observed substantial spatial and temporal variation in these values across the basin and within and among seasons. Glider-based observations provide a wider horizontal and vertical perspective than other methods (e.g., ship- and satellite-based observations, buoys, and fixed moorings), and are therefore a valuable, complementary tool for Great Lakes limnology. The set of observations reported here provide seasonal and basin-scale information that may help to identify anomalies useful for future glider-assisted investigation into the role of biophysical processes in Great Lakes limnology and ecology.

大湖研究合作研究所 (CIGLR) 与大湖观测系统和国家海洋和大气管理局合作，大湖环境研究实验室 (NOAA GLERL) 在 2012 年至 2012 年间每年数次在密歇根湖南部部署了自动水下滑翔机。 2019 年收集近海（>30 m 深度）湖沼学测量值，包括温度、光合有效辐射（从 2015 年开始）和叶绿素-α荧光。根据这些数据，我们计算了混合层深度、光穿透的几种度量（漫射衰减系数、第一光学深度、透光区深度）和地下叶绿素深度-α最大值。夏季，平均海上混合层深度一般为 10-15 m，PAR 的K _d为 0.1-0.17 m ^-1，第一光学深度为 6-9 m，透光区深度为 35-40 m，次表层叶绿素深度-α最大值为 30-35 m。我们还观察到整个盆地以及季节内和季节之间这些值的显着时空变化。基于滑翔机的观测提供了比其他方法（例如，基于船舶和卫星的观测、浮标和固定系泊设备）更广泛的水平和垂直视角，因此是五大湖湖沼学的一种有价值的补充工具。这里报告的一组观测提供了季节性和盆地尺度的信息，可能有助于识别异常情况，这些异常情况对未来滑翔机辅助调查生物物理过程在五大湖湖沼学和生态学中的作用有用。