%ALauderdale, Jonathan [Department of Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology Cambridge MA USA]%ACael, B. [Ocean Biogeosciences National Oceanography Centre Southampton UK]%BJournal Name: Geophysical Research Letters; Journal Volume: 48; Journal Issue: 7; Related Information: CHORUS Timestamp: 2023-08-23 19:52:55 %D2021%IDOI PREFIX: 10.1029 %JJournal Name: Geophysical Research Letters; Journal Volume: 48; Journal Issue: 7; Related Information: CHORUS Timestamp: 2023-08-23 19:52:55 %K %MOSTI ID: 10368862 %PMedium: X %TImpact of Remineralization Profile Shape on the Air‐Sea Carbon Balance %XAbstract

The ocean's “biological pump” significantly modulates atmospheric carbon dioxide levels. However, the complexity and variability of processes involved introduces uncertainty in interpretation of transient observations and future climate projections. Much research has focused on “parametric uncertainty,” particularly determining the exponent(s) of a power‐law relationship of sinking particle flux with depth. Varying this relationship's functional form introduces additional “structural uncertainty.” We use an ocean biogeochemistry model substituting six alternative remineralization profiles fit to a reference power‐law curve, to systematically characterize structural uncertainty, which, in atmospheric pCO2terms, is roughly 50% of parametric uncertainty associated with varying the power‐law exponent within its plausible global range, and similar to uncertainty associated with regional variation in power‐law exponents. The substantial contribution of structural uncertainty to total uncertainty highlights the need to improve characterization of biological pump processes, and compare the performance of different profiles within Earth System Models to obtain better constrained climate projections.

%0Journal Article