Wenmin Man

Effects of Large Volcanic Eruptions on Global Summer Climate and East Asian Monsoon Changes during the Last Millennium: Analysis of MPI-ESM Simulations

AbstractResponses of summer [June–August (JJA)] temperature and precipitation to large volcanic eruptions are analyzed using the millennial simulations of the earth system model developed at the Max Planck Institute for Meteorology. The model was driven by up-to-date reconstructions of external forcing, including natural forcing (solar and volcanic) and anthropogenic forcing (land-cover change and greenhouse gases). Cooling anomalies after large volcanic eruptions are seen on a nearly global scale. The cooling in the Northern Hemisphere (NH) is stronger than in the Southern Hemisphere (SH), and cooling is stronger over the continents than over the oceans. The precipitation decreases in the tropical and subtropical regions in the first summer after large volcanic eruptions. The cooling, with amplitudes of up to −0.6°C, is also seen over eastern China. East Asia is dominated by northerly wind anomalies, and the corresponding summer rainfall exhibits a coherent reduction over the entirety of eastern China. T...

Simulation of the east asian summer monsoon during the last millennium with the MPI earth system model

AbstractThe decadal–centennial variations of East Asian summer monsoon (EASM) and the associated rainfall change during the past millennium are simulated using the earth system model developed at the Max Planck Institute for Meteorology. The model was driven by up-to-date reconstructions of external forcing including the recent low-amplitude estimates of solar variations. Analysis of the simulations indicates that the EASM is generally strong during the Medieval Warm Period (MWP; A.D. 1000–1100) and weak during the Little Ice Age (LIA; A.D. 1600–1700). The monsoon rainband exhibits a meridional tripolar pattern during both epochs. Excessive (deficient) precipitation is found over northern China (35°–42°N, 100°–120°E) but deficient (excessive) precipitation is seen along the Yangtze River valley (27°–34°N, 100°–120°E) during the MWP (LIA). Both similarities and disparities of the rainfall pattern between the model results herein and the proxy data have been compared, and reconstructions from Chinese histor...

Chinese Contribution to CMIP5:An Overview of Five Chinese Models' Performances

An overview of Chinese contribution to Coupled Model Intercomparison Project-Phase 5 (CMIP5) is presented. The performances of five Chinese Climate/Earth System Models that participated in the CMIP5 project are assessed in the context of climate mean states, seasonal cycle, intraseasonal oscillation, interannual variability, interdecadal variability, global monsoon, Asian-Australian monsoon, 20th-century historical climate simulation, climate change projection, and climate sensitivity. Both the strengths and weaknesses of the models are evaluated. The models generally show reasonable performances in simulating sea surface temperature (SST) mean state, seasonal cycle, spatial patterns of Madden-Julian oscillation (MJO) amplitude and tropical cyclone Genesis Potential Index (GPI), global monsoon precipitation pattern, El Niño-Southern Oscillation (ENSO), and Pacific Decadal Oscillation (PDO) related SST anomalies. However, the performances of the models in simulating the time periods, amplitude, and phase locking of ENSO, PDO time periods, GPI magnitude, MJO propagation, magnitude of SST seasonal cycle, northwestern Pacific monsoon and North American monsoon domains, as well as the skill of large-scale Asian monsoon precipitation need to be improved. The model performances in simulating the time evolution and spatial pattern of the 20th-century global warming and the future change under representative concentration pathways projection are compared to the multimodel ensemble of CMIP5 models. The model discrepancies in terms of climate sensitivity are also discussed.

Regional-scale Surface Air Temperature and East Asian Summer Monsoon Changes during the Last Millennium Simulated by the FGOALS-gl Climate System Model

The spatial patterns and regional-scale surface air temperature (SAT) changes during the last millennium, as well as the variability of the East Asian summer monsoon (EASM) were simulated with a low-resolution version of Flexible Global Ocean-Atmosphere-Land-Sea-ice (FGOALS-gl) model. The model was driven by both natural and anthropogenic forcing agents. Major features of the simulated past millennial Northern Hemisphere (NH) mean SAT variations, including the Medieval Climate Anomaly (MCA), the Little Ice Age (LIA) and the 20th Century Warming (20CW), were generally consistent with the reconstructions. The simulated MCA showed a global cooling pattern with reference to the 1961–90 mean conditions, indicating the 20CW to be unprecedented over the last millennium in the simulation. The LIA was characterized by pronounced coldness over the continental extratropical NH in both the reconstruction and the simulation. The simulated global mean SAT difference between the MCA and LIA was 0.14°C, with enhanced warming over high-latitude NH continental regions. Consistencies between the simulation and the reconstruction on regional scales were lower than those on hemispheric scales. The major features agreed well between the simulated and reconstructed SAT variations over the Chinese domain, despite some inconsistency in details among different reconstructions. The EASM circulation during the MCA was stronger than that during the LIA The corresponding rainfall anomalies exhibited excessive rainfall in the north but deficient rainfall in the south. Both the zonal and meridional thermal contrast were enhanced during the MCA. This temperature anomaly pattern favored a stronger monsoon circulation.

A Robustness Analysis of CMIP5 Models over the East Asia-Western North Pacific Domain

Abstract The Coupled Model Intercomparison Project (CMIP) is an international community-based infrastructure that supports climate model intercomparison, climate variability, climate prediction, and climate projection. Improving the performance of climate models over East Asia and the western North Pacific has been a challenge for the climate-modeling community. In this paper, we provide a synthesis robustness analysis of the climate models participating in CMIP-Phase 5 (CMIP5). The strengths and weaknesses of the CMIP5 models are assessed from the perspective of climate mean state, interannual variability, past climate change during the mid-Pliocene (MP) and the last millennium, and climate projection. The added values of regional climate models relative to the driving global climate models are also assessed. Although an encouraging increase in credibility and an improvement in the simulation of mean states, interannual variability, and past climate changes are visible in the progression from CMIP3 to CMIP5, some previously noticed biases such as the ridge position of the western North Pacific subtropical high and the associated rainfall bias are still evident in CMIP5 models. Weaknesses are also evident in simulations of the interannual amplitude, such as El Nino-Southern Oscillation (ENSO)-monsoon relationships. Coupled models generally show better results than standalone atmospheric models in simulating both mean states and interannual variability. Multi-model intercomparison indicates significant uncertainties in the future projection of climate change, although precipitation increases consistently across models constrained by the Clausius-Clapeyron relation. Regional ocean-atmosphere coupled models are recommended for the dynamical downscaling of climate change projections over the East Asia-western North Pacific domain.

Different Impacts of Northern, Tropical, and Southern Volcanic Eruptions on the Tropical Pacific SST in the Last Millennium

AbstractThe impact of northern, tropical, and southern volcanic eruptions on the Pacific sea surface temperature (SST) and the different response mechanisms arising due to differences in the volcan...

The FGOALS climate system model as a modeling tool for supporting climate sciences: An overview

Climate system models are useful tools for understanding the interactions among the components of the climate system and predicting/projecting future climate change. The development of climate models has been a central focus of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences (LASG/IAP) since the establishment of the laboratory in 1985. In China, many pioneering component models and fully coupled models of the climate system have been developed by LASG/IAP. The fully coupled climate system developed in the recent decade is named FGOALS (Flexible Global Ocean‐Atmosphere‐Land System Model). In this paper, an application‐oriented review of the LASG/IAP FGOALS model is presented. The improved model performances are demonstrated in the context of cloud‐radiation processes, Asian monsoon, ENSO phenomena, Atlantic Meridional Overturning Circulation (AMOC) and sea ice. The FGOALS model has contributed to both CMIP5 (Coupled Model Intercomparison Project‐phase 5) and IPCC (Intergovernmental Panel on Climate Change) AR5 (the Fifth Assessment Report). The release of FGOALS data has supported the publication of nearly 500 papers around the world. The results of FGOALS are cited ~106 times in the IPCC WG1 (Working Group 1) AR5. In addition to the traditional long‐term simulations and projections, near‐term decadal climate prediction is a new set of CMIP experiment, progress of LAGS/IAP in the development of near‐term decadal prediction system is reviewed. The FGOALS model has supported many Chinese national‐level research projects and contributed to the national climate change assessment report. The crucial role of FGOALS as a modeling tool for supporting climate sciences is highlighted by demonstrating the models performances in the simulation of the evolution of Earths climate from the past to the future.

Brief Overview of FGOALS CMIP5 Experiments

The overview provides a useful reference for FGOALS CMIP5 experiments. Major improvements of FGOALS component models used in CMIP5 are introduced. The foci are the improvements of physical packages used in AGCM and OGCM models. The CMIP5 experiments conducted by using two versions of FGOALS model are also summarized along with lists in tables.