The Climatology and Interannual Variability of the East Asian Winter Monsoon in CMIP5 Models

Abstract

In this paper the model outputs from the Coupled Model Intercomparison Project (CMIP) phase 5 (CMIP5) are used to examine the climatology and interannual variability of the East Asian winter monsoon (EAWM). The multimodel ensemble (MME) is able to reproduce reasonably well the circulation features of the EAWM. The simulated surface air temperature still suffers from a cold bias over East Asia, but this bias is reduced compared with CMIP phase 3 models. The intermodel spread is relatively small for the large-scale circulations, but is large for the lower-tropospheric meridional wind and precipitation along the East Asian coast. The interannual variability of the EAWM-related circulations can be captured by most of the models. A general bias is that the simulated variability is slightly weaker than in the observations. Based on a selected dynamic EAWM index, the patterns of the EAWM-related anomalies are well reproduced in MME although the simulated anomalies are slightly weaker than the observations. One general bias is that the northeasterly anomalies over East Asia cannot be captured to the south of 308N. This bias may arise both from the inadequacies of the EAWM index and from the ability of models to capture the EAWM-related tropical-extratropical interactions. The ENSO-EAWM relationship is then evaluated and about half of the models can successfully capture the observed ENSO-EAWM relationship, including the significant negative correlation between Niño-3.4 and EAWM indices and the anomalous anticyclone (or cyclone) over the northwestern Pacific. The success of these models is attributed to the reasonable simulation of both ENSO's spatial structure and its strength of interannual variability.

Winter climate changes over East Asian region under RCP scenarios using East Asian winter monsoon indices

“…Jiang and Tian (2013) evaluated the changes in the EAWM under the impact of global warming in 23 CMIP3 and 19 CMIP5 models and obtained similar results to Wei and Bao (2012). Gong et al (2014) analyzed the climatology and interannual variations of the EAWM under the current climate, Wei and Bao (2012) used a single CGCM, and Jiang and Tian (2013) focused on changes of the EAWM in terms of only time series and mean fields.…”

“…The coupled general circulation model (CGCM) is an ultimate tool to describe the possible future change as well as the mechanism of EAWM (Kharin et al 2007;Gong et al 2014). However, limited studies have been performed to enhance our understanding of the EAWM under future climate change scenarios (Wei and Bao 2012;Gong et al 2014) because of its complicated thermodynamics .…”

“…However, limited studies have been performed to enhance our understanding of the EAWM under future climate change scenarios (Wei and Bao 2012;Gong et al 2014) because of its complicated thermodynamics . Using a CGCM, Hu et al (2000) showed that the intensity of the EAWM weakens but the variances of the EAWM on the interannual and interdecadal scales are not much affected by global warming.…”

“…The new future forcing scenarios (Taylor et al 2012) are also applied to CMIP5. Gong et al (2014) assessed the interannual variability of the EAWM-related circulations of present-day simulations using 18 CMIP5 models and found that most of the models can capture and reproduce variabilities and circulations. Using CMIP5 model data, Wei and Bao (2012) argued that the EAWM became stronger and that interannual variability of temperature increased (decreased) around lower (higher) latitudes in future projections.…”

The effect of a well-resolved stratosphere on East Asian winter climate

“…There have been several evaluation studies with focus on the model reproduction of East Asian summer and winter monsoon climate (e.g., Boo et al 2011;Gong et al 2014;Wei and Bao 2012;Wei et al 2014). It was shown that in the winter season, the current state-of-the-art CMIP5 models have the ability to reproduce circulation in EA region and progress had been made to relieve the surface cold bias, which was observed in the CMIP3 model ensemble.…”