NOAA's Oscar Dyson conducting a research cruise in the Arctic Ocean. Credit: Carl Rhodes
Understanding how Alaska's vast marine ecosystems are changing requires long, consistent records — something scientists have rarely had access to in one place. Now, NOAA and CICOES scientists have released a public dataset that compiles nearly five decades of ocean observations into a single, accessible product.
Designed to support climate research, ecosystem modeling, and machine-learning applications, the Alaska Compendium of Ocean Profile Data, or ACOD, offers a single point of access to 47 years of hydrographic and nutrient sampling.
"By bringing together nearly 50 years of oceanographic observations into one resource, ACOD represents a huge step toward reducing data fragmentation and making it easier for scientists and managers to understand long-term ocean changes in Alaska," said co-author Phyllis Stabeno, a physical oceanographer at NOAA's Pacific Marine Environmental Laboratory.
ACOD is host to an enormous amount of data. It includes 29,717 vertical profiles of temperature and salinity from 495 cruises conducted between 1974 and 2021, along with 7,016 nutrient profiles representing over 45,000 water samples collected between 2001 and 2021. These data span the Chukchi Sea, Bering Sea, and Gulf of Alaska, and were collected by a wide variety of NOAA research programs including Ecosystems and Fisheries-Oceanography Coordinated Investigations, or EcoFOCI.
"The EcoFOCI sampling contained in this collection is equivalent to more than 16 continuous years at sea, with more than 7 million meters of profiles, which is actually enough to reach past the center of the Earth," said lead author Calvin Mordy, a CICOES oceanographer.
A major step forward
Until now, scientists studying Alaska waters often had to piece together data from that wide variety of NOAA research programs, which were scattered across an even larger assortment of research products, each with its own formats and quirks. ACOD addresses this by providing standardized formatting, rigorous quality control, and secondary variables such as bottom depth, mixed layer depth, and regional categories. While ACOD does not incorporate all possible variables from all possible data sources — particularly from data sources with no EcoFOCI affiliation — it does represent a major step forward in data accessibility.
"We used an early version of this compilation to validate coupled physical-biogeochemical models, and its consistency and completeness dramatically improved our ability to reproduce observed conditions," said Kelly Kearney, an oceanographer at NOAA's Alaska Fisheries Science Center who was not involved in ACOD's development. "This makes it possible to more effectively evaluate climatological conditions, vertical nutrient structure, and mixed layer depth across decades, which is critical for both ecosystem forecasting and machine-learning approaches."
As Kearney noted, ACOD is particularly valuable for model validation. Its nutrient database also offers potential for AI-driven statistical modeling and extrapolation in data-sparse regions. Future updates are planned to add oxygen, chlorophyll, and other variables, which will only serve to increase its functionality as a training and validation tool for AI products.
Good science, quickly
"The idea is to enable good science, quickly, "said second author Noel Pelland, a CICOES research scientist who served as the technical lead in ACOD's development. "Having datasets like this, that are one-click access, and cover decades — it's hard to overstate how much of a multiplier that can be."
In fact, Pelland mentioned that he and his colleagues have already taken advantage of ACOD to map out historical relationships between nutrients and winds on the Bering Shelf, which is the subject of a recent publication.
Pelland added, "As an observational scientist, I can think of a million sandbox ideas that would benefit from ACOD. And there have also been many projects in the past where we've run up against the limitation of not having access to something like this."
By bringing decades of observations together in a single, open resource, the Alaska Compendium of Ocean Profile Data aims to ease those constraints. Scientists should now encounter the problem of data scarcity less often, helping to accelerate research in one of the nation's most important marine regions — research that has tangible impacts on everyone whose lives and livelihoods depend on healthy, sustainable fisheries in Alaska waters.
By Heather Tabisola with contributions by Joe Selmont. Story originally posted at UW CICOES.
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The Alaska Compendium of Ocean Profile Data was built by a team of 11 CICOES and NOAA scientists, including Calvin Mordy, Noel Pelland, Shaun Bell, Wei Cheng, Jeanette Gann, Albert Hermann, Caitlyn McFarland, Jens Nielsen, Phyllis Stabeno, Margaret Sullivan, and Eric Wisegarver.
ACOD is archived on the Dryad open-data publishing platform, where it is preserved with version control and available in NetCDF and CSV formats. It is intended to be updated annually or biennially in coordination with ongoing sampling by NOAA’s EcoFOCI group, as well as the continued rescue and curation of older records. Researchers and the public can access ACOD via Dryad at https://doi.org/10.5061/dryad.gf1vhhn0t.