Data supporting publication "OCEAN BIOGEOCHEMICAL EXTREMES AND COMPOUND EVENTS"

• Main Author: Gruber, Nicolas
• Other Authors: Frölicher, Thomas L.
• Format: Other/Unknown Material
• Language: English
• Published: ETH Zurich 2021
• Subjects: Ocean extremes; ocean warming; ocean acidification; ocean deoxygenation; info:eu-repo/classification/ddc/550; Earth sciences; Pacific; Dee; Ocean acidification
• Online Access: https://hdl.handle.net/20.500.11850/501082; https://doi.org/10.3929/ethz-b-000501082

This dataset is associated with the Perspectives article entitled "OCEAN BIOGEOCHEMICAL EXTREMES AND COMPOUND EVENTS" written by N. Gruber, Philip W. Boyd, Thomas L. Frölicher, and Meike Vogt. The data provided here show the distribution in space and time of a number of ocean biogeochemical extremes as simulated by two models, i.e, the global GFDL Earth System Model and the regional ROMS-BEC model. The abstract of the publication: "The ocean is warming, losing oxygen, and it is being acidified, primarily as a result of anthropogenic carbon emissions(Breitburg et al., 2018; Cheng et al., 2017; Gattuso et al., 2015; Gruber, 2011). With ocean warming, acidification, and deoxygenation projected to increase for decades(Bopp et al., 2013; Kwiatkowski et al., 2020), extreme events, such as marine heatwaves(Oliver et al., 2021), are likely to intensify, occur more often, persist for longer, and extend over larger regions(Benedetti-Cecchi, 2021; Thomas Lukas Frölicher et al., 2018; Oliver et al., 2018, 2019). Nevertheless, our understanding of oceanic extreme events, associated with warming, low oxygen concentrations or high acidity, and their impacts on marine ecosystems remains limited(Burger et al., 2020; Hauri et al., 2013; Oliver et al., 2019, 2021; Smale et al., 2019; Wernberg et al., 2012). Of particular concern are compound events, multiple extreme events that occur simultaneously or in close sequence, because their individual effects may interact synergistically(Seneviratne et al., 2012). Here we assess patterns and trends in open ocean extremes based on the existing literature and global and regional model simulations. Furthermore, we discuss the potential impacts of individual and compound extremes on marine organisms and ecosystems. We propose a pathway towards an improved understanding of extreme events and the capacity of marine life to respond to them. The absolute conditions exhibited by today’s extreme events may be a harbinger of what may become “normal” in the future(Oliver et al., 2019). In consequence, pursuing this research effort may also help better understand the responses of marine organisms and ecosystems to future climate change." Model simulation results: Part I: global model results from the GFDL Earth System Model The global extreme event analysis was conducted with simulation results from the fully coupled Earth system model ESM2M developed at the Geophysical Fluid Dynamics Laboratory (GFDL) of the National Oceanic and Atmospheric Administration(Dunne et al., 2013). The atmosphere has a horizontal resolution of 2° latitude x 2.5° longitude and the ocean has a nominal horizontal resolution of 1° latitude and 1° longitude, increasing toward the Equator to up to 0.3°. Ocean biogeochemistry is simulated by the Tracers Of Phytoplankton with Allometric Zooplankton version 2.0 (TOPAZ2). It represents 30 prognostic tracers, includes three phytoplankton functional groups and implicitly simulated zooplankton activity. The GFDL ESM2M captures the observed large-scale biogeochemical patterns and variability. We use a 500-yr preindustrial control simulation with prescribed atmospheric CO2 concentrations at 286 ppm, as well as a historical simulation over the 1861-2005 period followed by a high (RCP8.5; RCP: Representative concentration pathway) simulation over the 2006-2100 period with prescribed atmospheric CO2 and non-CO2 greenhouse and natural forcing (Burger et al., 2020). The RCP8.5 scenario is a high emission scenario without effective climate policies, leading to continued growth in greenhouse gas emissions. Part II: regional model results from ROMS-BEC: The 2013-2015 “Blob” event was analyzed using hindcast simulations of the telescopic North Pacific setup of ROMS-BEC by ref((Frischknecht et al., 2017)). Briefly, the model system consists of the Regional Oceanic Modeling System (ROMS)(Shchepetkin & McWilliams, 2005) coupled to an updated version of the Biogeochemical/Ecological Model (BEC)(Moore et al., 2002). BEC explicitly resolves the cycling of four nutrient elements, which limit the growth of three phytoplankton functional groups, which are being kept under control by the grazing of a single zooplankton functional group. The model domain covers the entire Pacific, but has a strong resolution refinement toward the U.S. West Coast, with most of the area of interest having a resolution of 10 kilometers or better. The model was initialized from observations, and then run through the period 1970 to 2016 using daily fields of wind stress, solar short-wave radiation, and fluxes of heat and freshwater from ERA Interim(D. P. Dee et al., 2011).