Future change of the global monsoon revealed from 19 CMIP5 models

Abstract

[1] The variability of global monsoon area (GMA), global monsoon precipitation (GMP), and global monsoon intensity (GMI) in the present climate and the future warmer climate under Representative Concentration Pathways 4.5 (RCP4.5) scenario was examined based on 19 Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations. In the present-day simulations, the ensemble mean precipitation reproduces the observed GMA, GMP, and GMI, although the spread of individual models is large. In the RCP4.5 simulations, most (17 of 19) of the CMIP5 models project enhanced global monsoon activity, with the increases of GMA, GMP, and GMI by 1.9%, 3.2%, and 1.3%, respectively, per 1 K of surface warming. The diagnosis of a column-integrated moisture budget indicates that the increase in GMP is primarily attributed to the increases of moisture convergence and surface evaporation, whereas horizontal moisture advection has little effect. A further separation of dynamic and thermodynamic factors shows that increase of the moisture convergence comes mainly from the increase of water vapor, but is partly offset by the convergence effect. The increase of the surface evaporation is caused by the increase of sea-air specific humidity difference, while the change in surface wind speed plays a minor role. The GMP experiences a great year-to-year variation, and it is significantly negatively correlated with the Niño3.4 index averaged over a typical monsoon year (defined from May to the following April) in the pre-industrial control and present-day simulations, similar to observations. Under the RCP4.5 warming, such rainfall variability is intensified, and the relationship between monsoon and El Niño strengthens. A large proportion of intensification in the year-to-year monsoon rainfall variability arises from the land monsoon region.Citation: Hsu, P.-c., T. Li, H. Murakami, and A. Kitoh (2013), Future change of the global monsoon revealed from 19 CMIP5 models,

Evolutions of Asian Summer Monsoon in the CMIP3 and CMIP5 Models

“…From a global perspective, the coverage and intensity of monsoon precipitation has been verified by previous studies (Wang and Xu 1997;Zhou et al 2008;Hsu et al 2011;Hsu et al 2012;Hsu et al 2013;Lee and Wang 2014). As the largest monsoon system over the world, the variability of Asian summer monsoon (ASM) has also drawn a lot of attentions (Webster et al 1998).…”

Evaluation of soil moisture in CMIP5 simulations over the contiguous United States using in situ and satellite observations

“…This resolution was chosen to match the spatial resolution of the satellite observations. Bilinear interpolation is a common method for interpolating precipitation (Chen and Frauenfeld, 2014;Hsu et al, 2013;Qu et al, 2013). Crow et al (2012) demonstrated that large-scale spatial patterns of soil moisture are dominated by precipitation.…”

Orographic Effects of the Tibetan Plateau on the East Asian Summer Monsoon: An Energetic Perspective

“…Fundamental questions, such as what controls the location and the seasonal evolution of the EASM front, or why maximum rainfall is not colocated with maximum SSTs, remain largely unanswered. Finding answers to these questions is even more pressing in the face of the predicted expansion of subtropical dry zones with climate change, with potentially significant impacts on subtropical precipitation fronts such as the EASM, and enhanced regional sensitivity to greenhouse gases and aerosol radiative forcing (e.g., Hirahara et al 2012;Hsu et al 2013). In this paper, we attempt to address some of these questions, and we specifically focus on the mechanisms through which the TP affects the formation and seasonality of the EASM.…”