A multi-year, seasonally resolved dataset of Seaglider observations at Station ALOHA in the North Pacific Subtropical Gyre

We present a large, quality-controlled dataset consisting of autonomous underwater measurements of hydrographical (temperature, salinity, and pressure), chemical (dissolved oxygen concentration), and bio-optical (chlorophyll a concentration and particulate backscatter) properties. Data were collected using underwater gliders on 18 missions in the North Pacific Subtropical Gyre between 2008 and 2023 (>20,000 vertical profiles). Each mission was centered near the long-term sampling site of the Hawaii Ocean Time-series program, Station ALOHA (A Long-term Oligotrophic Habitat Assessment). Measurements were quality controlled and calibrated to provide a robust dataset, inter-comparable among missions. We compare depth-resolved seasonality of Seaglider observations to previously described seasonal climatologies at Station ALOHA from ship-based observations. Results show that underwater gliders can accurately characterize ocean physical and biogeochemical conditions, reconstruct seasonality, and observe spatial variability and stochastic events in the absence of extensive ship operations. Further, these data allow us to study the variability of features, such as the chlorophyll and oxygen subsurface maxima with a temporal resolution of a few hours during multiple months.