Impacts of Tibetan Plateau uplift on atmospheric dynamics and associated precipitation δ<sup>18</sup>O
Abstract. Paleoelevation reconstructions of mountain belts have become a focus of modern science since surface elevation provides crucial information for understanding both geodynamic mechanisms of Earth’s interior and influence of mountains growth on climate. Stable oxygen isotopes paleoaltimetry is one of the most popular techniques nowadays, and relies on the difference between δ18O of paleo-precipitation reconstructed using the natural archives, and modern measured values for the point of interest. Our goal is to understand where and how complex climatic changes linked with the growth of mountains affect δ18O in precipitation. For this purpose, we develop a theoretical expression for the precipitation composition and we use the isotope-equipped atmospheric general circulation model LMDZ-iso. Experiments with reduced height over the Tibetan Plateau and the Himalayas have been designed. Our results show that the isotopic composition of precipitation is very sensitive to climate changes related with the growth of the Himalayas and Tibetan Plateau, notably changes in relative humidity and precipitation amount. The relative contribution of controlling factors and their magnitude differ depending on the uplift stage and the region considered. Thus future paleoaltimetry studies should take into account constraints on climatic factors to avoid misestimating ancient altitudes.