B23J-05
Changing ocean biogeochemistry in the CESM Large Ensemble
Tuesday, 15 December 2015: 14:40
2010 (Moscone West)
Nicole S Lovenduski1, Galen A McKinley2, Amanda R Fay2, Matthew C Long3 and Keith T Lindsay4, (1)University of Colorado, Boulder, CO, United States, (2)Univ. Wisconsion - Madison, Madison, WI, United States, (3)National Center for Atm Res, Boulder, CO, United States, (4)National Center for Atmospheric Research, Climate & Global Dynamics Division, Boulder, CO, United States
Abstract:
The oceans are predicted to absorb excess heat and carbon dioxide from the atmosphere over the coming century as a result of anthropogenic climate change, having both direct and indirect consequences for ocean biogeochemistry and ecosystems. Observations of ocean biogeochemistry collected over the past few decades document decreases in surface ocean pH, thermocline oxygen, and phytoplankton productivity. Such changes are often interpreted in the context of anthropogenic climate change, but internally-generated climate variability may also contribute. Here, we isolate the effects of anthropogenic climate change from those of internal variability on ocean biogeochemistry using the CESM Large Ensemble. The ensemble includes 34 members, each of which is subject to identical external forcing over 1920-2100 but starts from a slightly different atmospheric state. We quantify and characterize the drivers of both the anthropogenic and internal signals in ocean biogeochemistry on global and regional scales.
