Land heat uptake: from Last Millenium proxy and model simulations to observational and CMIP6 products
- 1Universidad Complutense de Madrid, Physics Faculty, Physics of the Earth & Astrophysics, Madrid, Spain (felgar03@ucm.es)
- 2Balearic Ocean Centre, Spanish Institute of Oceanography (IEO-CSIC), Palma de Mallorca, Spain
- 3Norwegian Research Centre, NORCE, Bergen, Norway
- 4Max Planck Institute for Meteorology, Hamburg, Germany
- 5Helmholtz-Zentrum Hereon, Geesthacht, Germany
- 6Research Centre for Energy, Environment and Technology (CIEMAT), Madrid, Spain
Observational studies based on borehole temperature profiles provide estimates of the land component contribution to the terrestrial energy budget to be 5 %, while CMIP5 (Coupled Model Intercomparison Project Phase 5) based estimates scale it down to 2 %. This discrepancy might have sensitive implications for the anthropogenically-driven energy surplus partition between the different components. At least part of this difference is likely due to state-of-the-art Land Surface Models (LSMs) in current Earth System Models (ESMs) being too shallow, thus constraining land heat uptake.
Séneca, a 2100-year-long fully-coupled forced simulation (Past2k + historical period + SSP585 future scenario, P2k+) using version 1.2 of the Max Planck Institute Earth System Model (MPI-ESM1.2-LR) with a deep BBCP (1417 m) is used to assess the behavior of subsurface temperatures and heat storage at long-term scales. It was run using Tier 3 forcing protocol defined in Paleoclimate Model Intercomparison Project Phase 4 (PMIP4) within the Coupled Model Intercomparison Project Phase 6 (CMIP6). Results show that Séneca land heat uptake by the end of the historical period is 4 times higher than for a P2k+ PMIP4- CMIP6 standard (about 10 m) simulation, also well above estimates provided by CMIP6 models. However, deepening the BBCP had no effect on surface temperature variability. This finding provides a strong basis for the use of a one-dimensional conductive forward model to obtain more reliable estimates of land heat uptake from complementary surface temperature sources, such as gridded observational datasets and reanalysis products. Furthermore, it enables the correction of shallow land surface model-based CMIP6 heat uptake estimates. The values obtained from this new approach (9-14 ZJ in 1971-2018) are in close agreement with the values derived from the MPI-ESM deep simulation (10 ZJ), but still below the last borehole-based estimates (19-25 ZJ).
How to cite: García-Pereira, F., González-Rouco, J. F., Melo-Aguilar, C., Steinert, N. J., de Vrese, P., Jungclaus, J., Lorenz, S., Hagemann, S., García-Bustamante, E., and Roldán-Gómez, P. J.: Land heat uptake: from Last Millenium proxy and model simulations to observational and CMIP6 products, EMS Annual Meeting 2023, Bratislava, Slovakia, 4–8 Sep 2023, EMS2023-584, https://doi.org/10.5194/ems2023-584, 2023.
