Ocean Acidification Indices with an Operational Ocean Model Product in the North Western Pacific

Miho Ishizu, Yasumasa Miyazawa, and Xinyu Guo, members of Application Laboratory, JAMSTEC and others have published a paper entitled “Development of a Biogeochemical and Carbon Model Related to Ocean Acidification Indices with an Operational Ocean Model Product in the North Western Pacific”. 

By using this operational model (JCOPE_EC), they have already launched a trial to perform a nowcast/forecast experiment targeting ocean acidification indices (pHinsitu and Ωarg), which are reproduced with the nowcast/forecast operational ocean model products. A website (https://www.marinecrisiswatch.jp/mcwatch/prediction/jcope/index.html) experimentally shows up-to-date results of the nowcast/forecast system to demonstrate our studies effectively.

Ishizu, M., Y. Miyazawa, T. Tsunoda, and X. Guo, 2019: Development of a Biogeochemical and Carbon Model Related to Ocean Acidification Indices with an Operational Ocean Model Product in the North Western Pacific. Sustainability, 11, doi:10.3390/su11092677.

Abstract:

We developed a biogeochemical and carbon model (JCOPE_EC) coupled with an operational ocean model for the North Western Pacific. JCOPE_EC represents ocean acidification indices on the background of the risks due to ocean acidification and our model experiences. It is an off-line tracer model driven by a high-resolution regional ocean general circulation model (JCOPE2M). The results showed that the model adequately reproduced the general patterns in the observed data, including the seasonal variability of chlorophyll-a, dissolved inorganic nitrogen/phosphorus, dissolved inorganic carbon, and total alkalinity. We provide an overview of this system and the results of the model validation based on the available observed data. Sensitivity analysis using fixed values for temperature, salinity, dissolved inorganic carbon and total alkalinity helped us identify which variables contributed most to seasonal variations in the ocean acidification indices, pH and Ωarg. The seasonal variation in the pHinsitu was governed mainly by balances of the change in temperature and dissolved inorganic carbon. The seasonal increase in Ωarg from winter to summer was governed mainly by dissolved inorganic carbon levels.