CERESMIP: Investigating Recent Trends in Earth’s Energy Imbalance (EEI)
In collaboration with a team of US, UK, Canadian, Japanese, German, and Australian collaborators, Lawrence Livermore Lab scientists have defined a new model intercomparison protocol to assess changes to top-of-atmosphere (ToA) radiant fluxes in response to ongoing climate change. The protocol outlines 10 revised and new model experiments that target an investigation into what is driving the model ToA radiant responses to ongoing change.
This new work will target pronounced discrepancies between the latest NASA CERES and the latest generation CMIP6 climate model historical simulations in the partitioning of incoming and outgoing radiant fluxes. Most current generation models show underestimated trends in the incoming shortwave (SW) fluxes, which are somewhat compensated for by overestimated outgoing longwave (LW) fluxes. However, the results differ markedly across individual model configurations, with the unforced internal variability of some models leading to ensemble members which span the observed estimate. The proposed experiments outline a protocol for multi-model experimentation that investigates a suite of combined forcing, single forcing, and all-but-one (forcing) experiments that will improve our understanding of the source of the model and observational disagreement.
The new protocol and planned work will leverage the latest observations, combined with the latest available climate-forcing datasets to determine the source of disagreement between SW and LW flux partitioning over the well-observed modern period. This work will leverage new forcing datasets being developed by the CMIP Forcing Task Team, in addition to some complementary NASA data products that provide limited temporal coverage over the CERES period (2001 to present). The protocol defines light-weight atmospheric-only simulations that will begin in late 2023/early 2024, with data published into the CMIP6Plus project facilitating coordination between the eight contributing modeling groups, along with broader collaborator and community access, much like the preceding CMIP6 archive.