Simulation of the interface between the Indian summer monsoon and the East Asian summer monsoon: Intercomparison between MPI-ESM and ECHAM5/MPI-OM

Yiran Guo,Hui Li,Jian Wang,Jie Cao,Yuchao Ding

doi:10.1007/s00376-015-5073-z

Yiran Guo, Hui Li + Show 3 more

Open Access

https://doi.org/10.1007/s00376-015-5073-z

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Journal: Advances in atmospheric sciences	Publication Date: Mar 1, 2016
Citations: 17	License type: CC BY 4.0

Affiliation: Yunnan University

Abstract

The time-mean and interannual variability of the interface between the Indian summer monsoon and East Asian summer monsoon (IIE) was assessed using both Max-Planck-Institute Earth System Model (MPI-ESM) and ECHAM5/MPI-OM and by calculating diagnostics and skill metrics around the IIE area. Progress has been made in modeling these aspects by moving from ECHAM5/MPI-OM to MPI-ESM. MPI-ESM is more skillful than ECHAM5/MPI-OM in modeling the time-mean state and the extreme condition of the IIE. Though simulation of the interannual variability significantly deviates to some extent in both MPI-ESM and ECHAM5/MPI-OM, MPI-ESM-LR shows better skill in reflecting the relationship among sea surface temperature anomalies over the Pacific, circulation anomalies over East Asia, and IIE variability. The temperature becomes warmer under the RCP2.6 and RCP8.5 scenarios in comparison with the historical experiments, but the position of the IIE and the key physical process in relation to the IIE variability almost remains the same, suggesting that the Indian summer monsoon tends to change in phase with the East Asian summer monsoon under each RCP scenario. The relatively realistic description of the physical processes modulated by terrain in MPI-ESM may be one of the most important reasons why MPI-ESM performs better in simulating the IIE.

Highlights

The Asian monsoon influences more than 60% of the world’s population, through controlling droughts and floods, and plays a key role in the Earth’s climate system (Flohn, 1957; Ding, 1994; Webster et al, 1998; Huang et al, 2012; Wu et al, 2012)
Some improvements have been made in Max-Planck-Institute Earth System Model (MPI-ESM)-MR, including increased vertical resolution, while in MPI-ESM-LR it remains the same resolution as ECHAM5/MPI-OM (Jungclaus et al, 2013)
Compared to MPIESM-LR and ECHAM5/MPI-OM, MPI-ESM-MR best captures the observational pattern of the vertical mean temperature at 200–500 hPa. These results suggest that MPI-ESMMR possesses a better simulation capability for the middle– upper troposphere, possibly because of the higher vertical resolution of MPI-ESM-MR compared with MPI-ESM-LR or ECHAM5/MPI-OM

Summary

Introduction

The Asian monsoon influences more than 60% of the world’s population, through controlling droughts and floods, and plays a key role in the Earth’s climate system (Flohn, 1957; Ding, 1994; Webster et al, 1998; Huang et al, 2012; Wu et al, 2012). ECHAM5, released in 2003, has been extensively used in studying the variation of the Asian summer monsoon because of its high simulation efficiency (Roeckner et al, 2003, 2006; Marsland et al, 2003). As the IIE is a variable that describes the interaction between the East Asian summer monsoon and Indian summer monsoon, simulation of IIE variation may be crucial in understanding the impact of the two monsoon subsystems on local weather and climate. If the temporal and spatial evolution of the IIE can be better reproduced in GCMs, the skill of numerical models in simulating the Asian summer monsoon may be improved. The aim of this study, was to establish whether MPI-ESM can provide a better representation in modeling the IIE, and, if this is the case, determine the kinds of improvements that can be achieved.

Model and data

Position of the IIE

SST and circulation anomalies associated with IIE variability

Findings

Summary and discussion