Modeling the late Pliocene global monsoon response to individual boundary conditions.

The late Pliocene is a pre-Quaternary warming period compared to the preindustrial period. Here, based on the updated PRISM4 (Pliocene Research, Interpretation and Synoptic Mapping version 4) boundary conditions from the Pliocene Model Intercomparison Project phase 2 (PlioMIP2), seven experiments are conducted to simulate the global monsoon in the late Pliocene interglacial period and further investigate the impacts from changes in the individual boundary conditions by using the Community Earth System Model (CESM 1.0.4). The simulated late Pliocene interglacial climate is generally warmer and wetter than the preindustrial period climate, with an expanded monsoon domain, particularly in North Africa, Asia and Australia. The differences in topography, vegetation and lakes outside of Greenland and Antarctica account for the greatest contribution to monsoon changes. Moreover, orbital parameter variations further significantly affect monsoon domains and lead to significant fluctuations in monsoon precipitation and winds on the orbital scale, and the changed magnitude is even larger than that between the late Pliocene and preindustrial period when orbital forcing is not considered. [ABSTRACT FROM AUTHOR]