Details:

Alternative Title:
Global projections for ocean conditions in 2100 predict that the North Pacific will experience some of the largest changes. Coastal processes that drive variability in the region can alter these projected changes but are poorly resolved by global coarse-resolution models. We quantify the degree to which local processes modify biogeochemical changes in the eastern boundary California Current System (CCS) using multi-model regionally downscaled climate projections of multiple climate-associated stressors (temperature, O2, pH, saturation state (Ω), and CO2). The downscaled projections predict changes consistent with the directional change from the global projections for the same emissions scenario. However, the magnitude and spatial variability of projected changes are modified in the downscaled projections for carbon variables. Future changes in pCO2 and surface Ω are amplified, while changes in pH and upper 200 m Ω are dampened relative to the projected change in global models. Surface carbon variable changes are highly correlated to changes in dissolved inorganic carbon (DIC), pCO2 changes over the upper 200 m are correlated to total alkalinity (TA), and changes at the bottom are correlated to DIC and nutrient changes. The correlations in these latter two regions suggest that future changes in carbon variables are influenced by nutrient cycling, changes in benthic–pelagic coupling, and TA resolved by the downscaled projections. Within the CCS, differences in global and downscaled climate stressors are spatially variable, and the northern CCS experiences the most intense modification. These projected changes are consistent with the continued reduction in source water oxygen; increase in source water nutrients; and, combined with solubility-driven changes, altered future upwelled source waters in the CCS. The results presented here suggest that projections that resolve coastal processes are necessary for adequate representation of the magnitude of projected change in carbon stressors in the CCS.
Journal Title:
Biogeosciences
Personal Author:
Siedlecki, Samantha A. ; Pilcher, Darren ; Howard, Evan M. ; Deutsch, Curtis ; MacCready, Parker ; ... More +
Siedlecki, Samantha A. ; Pilcher, Darren ; Howard, Evan M. ; Deutsch, Curtis ; MacCready, Parker ; Norton, Emily L. ; Frenzel, Hartmut ; Newton, Jan ; Feely, Richard A. ; Alin, Simone R. ; Klinger, Terrie Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; PMEL (Pacific Marine Environmental Laboratory) ; CICOES (Cooperative Institute for Climate, Ocean and Ecosystem Studies)
OAR (Oceanic and Atmospheric Research) ; PMEL (Pacific Marine Environmental Laboratory) ; CICOES (Cooperative Institute for Climate, Ocean and Ecosystem Studies) Less -
Description:
Global projections for ocean conditions in 2100 predict that the North Pacific will experience some of the largest changes. Coastal processes that drive variability in the region can alter these projected changes but are poorly resolved by global coarse-resolution models. We quantify the degree to which local processes modify biogeochemical changes in the eastern boundary California Current System (CCS) using multi-model regionally downscaled climate projections of multiple climate-associated stressors (temperature, O2, pH, saturation state (Ω), and CO2). The downscaled projections predict changes consistent with the directional change from the global projections for the same emissions scenario. However, the magnitude and spatial variability of projected changes are modified in the downscaled projections for carbon variables. Future changes in pCO2 and surface Ω are amplified, while changes in pH and upper 200 m Ω are dampened relative to the projected change in global models. Surface carbon variable changes are highly correlated to changes in dissolved inorganic carbon (DIC), pCO2 changes over the upper 200 m are correlated to total alkalinity (TA), and changes at the bottom are correlated to DIC and nutrient changes. The correlations in these latter two regions suggest that future changes in carbon variables are influenced by nutrient cycling, changes in benthic–pelagic coupling, and TA resolved by the downscaled projections. Within the CCS, differences in global and downscaled climate stressors are spatially variable, and the northern CCS experiences the most intense modification. These projected changes are consistent with the continued reduction in source water oxygen; increase in source water nutrients; and, combined with solubility-driven changes, altered future upwelled source waters in the CCS. The results presented here suggest that projections that resolve coastal processes are necessary for adequate representation of the magnitude of projected change in carbon stressors in the CCS.
Keywords:
[+]
Ocean currents
Source:
Biogeosciences, 18(9), 2871-2890
DOI:
https://doi.org/10.5194/bg-18-2871-2021
Document Type:
Journal Article
Place as Subject:
California
Rights Information:
CC BY
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:c50b381963ec1cd4dfdbc67440ab081ea09d59608b69fcf8474d87224a9cf6ba
Download URL:
https://repository.library.noaa.gov/view/noaa/30002/noaa_30002_DS1.pdf
File Type:

Supporting Files

• 	Available dataset	xml
  	Available dataset	xml

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