2026-07-22 東京大学,東京科学大学
地表気温とその変動性の現代と白亜紀の比較
＜関連情報＞
- https://www.aori.u-tokyo.ac.jp/research/news/2026/20260722.html
- https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025GL120337
白亜紀後期における北半球高緯度地域の気温の軌道強制力に対する感度が現代の地理と比較して高まっている Enhanced Orbital-Forcing Sensitivity of Northern High Latitude Temperatures in the Late Cretaceous Relative to Modern Geography
Taro Higuchi, Ayako Abe-Ouchi, Wing-Le Chan, Ryouta O’ishi
Geophysical Research Letters Published: 22 July 2026
DOI:https://doi.org/10.1029/2025GL120337
Abstract
Orbital forcing is a primary driver of paleoclimate change, but its influence on deep time climates, particularly in the polar regions of the Late Cretaceous, is poorly understood. Here, we conduct climate simulations with an atmosphere-ocean-vegetation coupled model, MIROC4mV, to investigate the response of northern high latitude temperature using Maastrichtian geography. By accounting for the full range of orbital parameters, the model successfully reproduces proxy-based estimates of polar temperatures. Our experiments show that the sensitivity of northern high latitude surface temperature to orbital forcing is higher with Maastrichtian geography than with Modern. In particular, Maastrichtian geography greatly amplifies obliquity-driven fluctuations due to the large continental landmass at northern high latitudes and the absence of ice sheets. These findings highlight the importance of considering the full range of orbital sensitivity when interpreting geological records from deep-time periods.
