Replaying the tape of history: Synthetic large ensembles of sea-air carbon dioxide (CO2) flux Journal Article uri icon

Overview

abstract

  • We use a statistical emulation technique to construct synthetic; ensembles of global and regional sea-air carbon dioxide (CO2) flux from; four observation-based products over 1985-2014. Much like ensembles of; Earth system models that are constructed by perturbing their initial; conditions, our synthetic ensemble members exhibit different phasing of; internal variability and a common externally forced signal. Our; synthetic ensembles illustrate an important role for internal; variability in the temporal evolution of global and regional CO2 flux; and produce a wide range of possible trends over 1990-1999 and; 2000-2009. We assume a specific externally forced signal and calculate; the likelihood of the observed trend given the distribution of synthetic; trends during these two periods. Over the decade 1990-1999, three of the; four observation-based products exhibit small negative trends in; globally integrated sea-air CO2 flux (i.e., enhanced ocean CO2; absorption with time) that are highly probable (44-72% chance of; occurrence) in their respective synthetic trend distributions. Over the; decade 2000-2009, however, three of the four products show large; negative trends in globally integrated sea-air CO2 flux that are; somewhat improbable (17-19% chance of occurrence). Our synthetic; ensembles suggest that the largest observation-based positive trends in; global and Southern Ocean CO2 flux over 1990-1999 and the largest; negative trends over 2000-2009 are somewhat improbable (<30%; chance of occurrence). Our approach provides a new understanding of the; role of internal and external processes in driving sea-air CO2 flux; variability.

publication date

  • September 6, 2021

has restriction

  • closed

Date in CU Experts

  • September 14, 2021 1:44 AM

Full Author List

  • Olivarez H; Lovenduski N; Brady R; Fay A; Gehlen M; Gregor L; Landschützer P; McKinnon K; MUNRO D

author count

  • 9

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