Contextualizing time-series data: Quantification of short-term regional variability in the San Pedro Channel using high-resolution in situ glider data

Abstract

Oceanic time-series have been instrumental in providing an understanding of biological, physical, and chemical dynamics in the oceans and how these processes change over time. However, the extrapolation of these results to larger oceanographic regions requires an understanding and characterization of local versus regional drivers of variability. Here we use highfrequency spatial and temporal glider data to quantify variability at the coastal San Pedro Ocean Time-series (SPOT) site in 20 the San Pedro Channel (SPC) and provide insight into the underlying oceanographic dynamics for the site. The dataset was dominated by four water column profile types: active upwelling, offshore influence, subsurface chlorophyll maximum, and surface bloom. On average, waters across the SPC were most similar to offshore profiles. On weekly timescales, the SPOT station was on average representative of 64% of profiles taken within the SPC, and SPOT was least similar to SPC locations that were closest to the Palos Verdes Peninsula. Subsurface chlorophyll maxima with co-located chlorophyll and particle 25 maxima were common in 2013 and 2014 suggesting that these subsurface chlorophyll maxima might contribute significantly to the local primary production. These results indicate that high-resolution in situ glider deployments can be used to determine the spatial domain of time-series data, allowing for broader application of these datasets and greater integration into modeling efforts.

Configuration and Validation of an Oceanic Physical and Biogeochemical Model to Investigate Coastal Eutrophication in the Southern California Bight

“…At SPOT, a region weakly influenced by anthropogenic nutrients inputs at the surface, the model realistically simulates the seasonal cycle of chlorophyll. While ammonium does not exceed typical “natural” values of ∼1 mmol m −3 below the surface, chlorophyll concentrations regularly reach more than 2 mg m −3 between 20 and 40 m in summer, in agreement with in situ measurement (Beman et al., 2011; Teel et al., 2018). (Additional figures to support the analysis are reported in Figure S23 of Supporting Information .…”

Net Community Production in a Productive Coastal Ocean From an Autonomous Buoyancy‐Driven Glider

“…This observation is unsurprising given the low-frequency seasonal warming and increased stratification that occur in the SCB as a result of increased solar insolation during the transition from spring into summer (Hickey et al, 2003). Chlorophyll concentration and inventory, an indicator of phytoplankton presence, was also generally higher in March/April than in May/June at both locations, which may be expected with higher rate of delivery of deep water nutrients into the euphotic zone from below (Eppley et al, 1979;Mantyla et al, 2008;Teel et al, 2018).…”

“…Lag between the flow‐through CTD temperature and salinity data was then corrected using the approach described by Garau et al () prior to making any further calculations. Temperature, salinity, and chlorophyll fluorescence data are discussed in detail by Teel et al (), characterizing water mass properties near SPOT.…”