Response of Monsoons to Extreme Climates Using an Idealized GCM

Thursday, 18 December 2014
Rebecca Payne and Jung-Eun Lee, Brown University, Providence, RI, United States
Monsoon responses to climate can be modeled using moist GCMs that utilize atmospheric fluid dynamics; we used a moist idealized GCM similar to that used by Frierson et al (2006). The model is an aquaplanet model, and includes a slab ocean with a mixed layer. Changing the transmissivity of the atmosphere through altering the longwave absorber optical thickness made it possible to study how moisture transport and monsoon circulation change as climate conditions change. The depth of the slab ocean mixed layer was also changed to further compare the development of Hadley circulation in different climate regimes. The goal of this research was to examine how monsoon centers, extents, and timing vary under a wide range of climates. Evidence of changing monsoon conditions can be seen in the significant shifts of the stream function, which in turn causes changes in temperature, precipitation, and meridional winds. The understanding of changes to monsoons during climate change could make it possible to analyze the response of the hydrological cycle in a variety of climate extremes such as Snowball Earth and Paleocene-Eocene Thermal Maximum periods.