Searching for the Blob: Physical and biogeochemical characteristics of the North Pacific marine heat wave in ocean models

In July of 2013, a marine heat wave, a period of anomalously warm sea surface temperatures, emerged in the northeastern Pacific Ocean and lasted until June of 2016. This significant event, referred to as the North Pacific Blob, had a large influence on marine ecosystems across the North Pacific Ocea...

Full description

Bibliographic Details
Other Authors: Dallmann, Allysa (author), Lovenduski, Nicole (contributor), Smith, Andrea (contributor), Olivarez, Holly (contributor), Smith, Dakota (contributor)
Format: Manuscript
Language:English
Published: 2021
Subjects:
Online Access:https://doi.org/10.5065/fcpy-7d51
Description
Summary:In July of 2013, a marine heat wave, a period of anomalously warm sea surface temperatures, emerged in the northeastern Pacific Ocean and lasted until June of 2016. This significant event, referred to as the North Pacific Blob, had a large influence on marine ecosystems across the North Pacific Ocean. While studies have examined the physical and ecological ramifications of the Blob using observations collected at sea, it is unknown whether state-of-the-art oceanographic models can reproduce this event. Here, we identified and described the physical and biogeochemical characteristics of the Blob using output from simulations of four models that were contributed to the 6th Coupled Model Intercomparison Project (CMIP6) Ocean Model Intercomparison Project Version 2 (OMIP2). During the Blob period in the Northeastern Pacific Ocean, OMIP2 models simulated anomalously warm sea surface temperatures (SSTs), anomalously low dissolved inorganic carbon (DIC) concentrations, and anomalously high saturation states for the mineral aragonite (�aragonite), as compared to pre-Blob climatological conditions. These findings were consistent with observations of the surface ocean in the real world during this period, though the magnitude of the SST, DIC, and �aragonite anomalies differed across different model structures. Our analysis revealed that the Blob influenced the physical and biogeochemical properties of the upper 100m of the ocean in each OMIP2 model. Our results suggest that ocean models are generally capable of capturing the physical and biogeochemical characteristics of marine heat waves and show how the Blob was associated with a temporary relief of ocean acidification, an ongoing environmental problem.