Akademik Veri Yönetim Sistemi
AGU Fall Meeting 2024, California, Amerika Birleşik Devletleri, 9 - 13 Aralık 2024, ss.1, (Özet Bildiri)
Climate models need information about initial boundary conditions for their simulations, such as the position and elevation of the land masses, the configuration of ocean gateways, and the composition of the atmosphere. The vegetation distribution and soil properties are also important boundary conditions because vegetation feedbacks can significantly influence regional climate simulations and climate sensitivity to CO2 forcing. Information about past vegetation and soil distributions comes primarily from the paleobotanical record, which, for the purposes of creating a global boundary condition, is often supplemented by a vegetation model to fill in the gaps. For recent periods of the past such as the Holocene, Last Glacial Maximum and the Pliocene, a quantitative assessment of the suitability of these vegetation model simulations is sufficient. However, the Miocene Climate Optimum (MCO) spanning 16.9-14.7 Ma was the warmest period on Earth over the last ~25 million years and the MioMIP1 models have struggled to reproduce those conditions for the range of paleogeographies and CO2 concentrations tested, particularly at high latitudes. Here we bring together the Middle Miocene modelling and proxy data communities to update previous vegetation reconstructions used for climate modelling using expert judgement and a new regional approach that relaxes the requirement for a single model simulation with a single CO2 concentration to be used in the reconstruction. This approach ensures that the simulated vegetation is consistent with the paleobotanical data, which is considered a more important factor than the consistency of CO2 levels across the reconstruction. The reconstruction shows a global increase in forest cover at all latitudes as compared to today and extensive grasslands across the high northern latitudes. To achieve this reconstruction, the data gaps at high latitude were filled with the outputs from vegetation models forced with higher CO2 concentration boundary conditions than were required for filling the gaps at the lower latitudes. The new MioVeg1 reconstruction will form the basis of the vegetation and soil boundary conditions for the forthcoming MioMIP2 project.