Uncertainties of Surface Mass Balance in Greenland for the mid-Holocene as derived from CMIP6/PMIP4 simulations.

The temporal evolution of Greenland’s surface mass balance (SMB) exerts an essential control on its volume, geometry, and sea-level contribution. Surface mass balance simulations based on future climate projections reveal considerable uncertainties. Here, we investigate Greenland’s SMB during past climate periods and assess the uncertainties due to model dependent climate forcing. Specifically we analyse the SMB of the pre-industrial climate and the mid-Holocene warm period.

 

We study the surface mass balance of the Greenland ice sheet with respect to uncertainties due to model dependent climate forcing. For this purpose, we create an ensemble based on the output of climate models of the sixth phase of the Coupled Model Intercomparison Project (CMIP6) and the fourth phase of the Paleomodel Intercomparison Project (PMIP4) (Brierley et al., 2020). This ensemble is used to simulate the SMB with the diurnal energy balance model (dEBM) (Krebs-Kanzow et al, 2021). As part of the analysis, we inspect anomalies and inter-model deviations of the mid-Holocene climate forcing, and evaluate the spread of spatial patterns of SMB anomalies in CMIP6/PMIP4. Our results indicate that the model-dependent climate forcing adds considerable uncertainty to SMB estimates over Greenland during the Holocene.

 

References

Brierley, C. M., Zhao, A., Harrison, S. P., Braconnot, P., Williams, C. J. R., Thornalley, D. J. R., Shi, X., Peterschmitt, J.-Y., Ohgaito, R., Kaufman, D. S., Kageyama, M., Hargreaves, J. C., Erb, M. P., Emile-Geay, J., D'Agostino, R., Chandan, D., Carré, M., Bartlein, P. J., Zheng, W., Zhang, Z., Zhang, Q., Yang, H., Volodin, E. M., Tomas, R. A., Routson, C., Peltier, W. R., Otto-Bliesner, B., Morozova, P. A., McKay, N. P., Lohmann, G., Legrande, A. N., Guo, C., Cao, J., Brady, E., Annan, J. D., and Abe-Ouchi, A., 2020: Large-scale features and evaluation of the PMIP4-CMIP6 midHolocene simulations, Clim. Past, 16, 1847–1872, doi:10.5194/cp-16-1847-2020, 2020. 

Krebs-Kanzow, U., Gierz, P., Rodehacke, C. B., Xu, S., Yang, H., and Lohmann, G., 2021: The diurnal Energy Balance Model (dEBM): a convenient surface mass balance solution for ice sheets in Earth system modeling, The Cryosphere, 15, 2295–2313, https://doi.org/10.5194/tc-15-2295-2021.