In this paper,experiment results about East Asia climate from five CGCMs are described.The ability of the models to simulate present climate and the simulated response to increased carbon dioxide are both covered.The ...In this paper,experiment results about East Asia climate from five CGCMs are described.The ability of the models to simulate present climate and the simulated response to increased carbon dioxide are both covered.The results indicate that all models show substantial changes in climate when carbon dioxide concentrations are doubled.In particular,the strong surface warming at high latitudes in winter and the significant increase of summer precipitation in the monsoon area are produced by all models.Regional evaluation results show that these five CGCMs are particularly good in simulating spatial distribution of present climate.The main characteristics of the seasonal mean H500,SAT, MSLP field can be simulated by most CGCMs.But there are significant systematic errors in SAT, MSLP,HS00 fields in most models.On the whole,DKRZ OPYC is the best in simulating the present climate in East Asia.展开更多
We present an overview of the El Ni?o–Southern Oscillation(ENSO) stability simulation using the Chinese Academy of Meteorological Sciences climate system model(CAMS-CSM). The ENSO stability was quantified based on th...We present an overview of the El Ni?o–Southern Oscillation(ENSO) stability simulation using the Chinese Academy of Meteorological Sciences climate system model(CAMS-CSM). The ENSO stability was quantified based on the Bjerknes(BJ) stability index. Generally speaking, CAMS-CSM has the capacity of reasonably representing the BJ index and ENSO-related air–sea feedback processes. The major simulation biases exist in the underestimated thermodynamic damping and thermocline feedbacks. Further diagnostic analysis reveals that the underestimated thermodynamic feedback is due to the underestimation of the shortwave radiation feedback, which arises from the cold bias in mean sea surface temperature(SST) over central–eastern equatorial Pacific(CEEP). The underestimated thermocline feedback is attributed to the weakened mean upwelling and weakened wind–SST feedback(μ_a) in the model simulation compared to observation. We found that the weakened μ_a is also due to the cold mean SST over the CEEP.The study highlights the essential role of reasonably representing the climatological mean state in ENSO simulations.展开更多
Using the ECMWF reanalysis daily 200-hPa wind data during the two 20-yr periods from 1958 to 1977 and from 1980 to 1999, the characteristics and changes of Intraseasonal Oscillations （ISO） in the two periods associa...Using the ECMWF reanalysis daily 200-hPa wind data during the two 20-yr periods from 1958 to 1977 and from 1980 to 1999, the characteristics and changes of Intraseasonal Oscillations （ISO） in the two periods associated with global warming are analyzed and compared in this study. It is found that during the last 20 years, the ISO has weakened in the central equatorial Pacific Ocean, but becomes more active in the central Indian Ocean and the Bay of Bengal; under the background of the global warming, increase in the amplitude of ISO intensity suggests that the ISO has become more active than before, with an obvious seasonal cycle, i.e., strong during winter and spring, but weak during summer and autumn; the energy of the upper tropospheric zonal winds has more concentrated in wave numbers 1-3, and the frequency of ISO tended to increase. Comparison between the results of control experiment and CO2 increase （1% per year） experiment of FGOALS-1.0g （developed at LASG） with the first and second 20-yr observations, is also performed, respectively. The comparative results show that the spatial structure of the ISO was well reproduced, but the strength of ISO was underestimated. On the basis of space-time spectral analysis, it is found that the simulated ISO contains too much high frequency waves, leading to the underestiniation of ISO intensity due to the dispersion of ISO energy. However, FGOALS-1.0g captured the salient features of ISO under the global warming background by two contrast experiments, such as the vitality and frequency-increasing of ISO in the central Indian Ocean and the Bay of Bengal.展开更多
基金The work was supported by the National ScienceTechnical Committee in China (85-913-02-05)+1 种基金Climate Prediction Program the National Postdocter Fund.
文摘In this paper,experiment results about East Asia climate from five CGCMs are described.The ability of the models to simulate present climate and the simulated response to increased carbon dioxide are both covered.The results indicate that all models show substantial changes in climate when carbon dioxide concentrations are doubled.In particular,the strong surface warming at high latitudes in winter and the significant increase of summer precipitation in the monsoon area are produced by all models.Regional evaluation results show that these five CGCMs are particularly good in simulating spatial distribution of present climate.The main characteristics of the seasonal mean H500,SAT, MSLP field can be simulated by most CGCMs.But there are significant systematic errors in SAT, MSLP,HS00 fields in most models.On the whole,DKRZ OPYC is the best in simulating the present climate in East Asia.
基金Supported by the National Natural Science Foundation of China(41606011 and 91637210)National Key Research and Development Program(2016YFE0102400,2016YFA0600602,and 2018YFC1506002)+3 种基金Basic Scientific Research and Operation Funds of the Chinese Academy of Meteorological Sciences(2017Y007)Startup Funds for Introduced Talents of Nanjing University of Information Science&TechnologyOpen Project Funds of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid DynamicsOpen Project Funds of the State Key Laboratory of Loess and Quartary Geology
文摘We present an overview of the El Ni?o–Southern Oscillation(ENSO) stability simulation using the Chinese Academy of Meteorological Sciences climate system model(CAMS-CSM). The ENSO stability was quantified based on the Bjerknes(BJ) stability index. Generally speaking, CAMS-CSM has the capacity of reasonably representing the BJ index and ENSO-related air–sea feedback processes. The major simulation biases exist in the underestimated thermodynamic damping and thermocline feedbacks. Further diagnostic analysis reveals that the underestimated thermodynamic feedback is due to the underestimation of the shortwave radiation feedback, which arises from the cold bias in mean sea surface temperature(SST) over central–eastern equatorial Pacific(CEEP). The underestimated thermocline feedback is attributed to the weakened mean upwelling and weakened wind–SST feedback(μ_a) in the model simulation compared to observation. We found that the weakened μ_a is also due to the cold mean SST over the CEEP.The study highlights the essential role of reasonably representing the climatological mean state in ENSO simulations.
基金Supported by the National Natural Science Foundation of China under Grant Nos.90211011 and 40231004the Science and Technology Department"Eleventh Five"programme under Grant No.2001BA611B01.
文摘Using the ECMWF reanalysis daily 200-hPa wind data during the two 20-yr periods from 1958 to 1977 and from 1980 to 1999, the characteristics and changes of Intraseasonal Oscillations （ISO） in the two periods associated with global warming are analyzed and compared in this study. It is found that during the last 20 years, the ISO has weakened in the central equatorial Pacific Ocean, but becomes more active in the central Indian Ocean and the Bay of Bengal; under the background of the global warming, increase in the amplitude of ISO intensity suggests that the ISO has become more active than before, with an obvious seasonal cycle, i.e., strong during winter and spring, but weak during summer and autumn; the energy of the upper tropospheric zonal winds has more concentrated in wave numbers 1-3, and the frequency of ISO tended to increase. Comparison between the results of control experiment and CO2 increase （1% per year） experiment of FGOALS-1.0g （developed at LASG） with the first and second 20-yr observations, is also performed, respectively. The comparative results show that the spatial structure of the ISO was well reproduced, but the strength of ISO was underestimated. On the basis of space-time spectral analysis, it is found that the simulated ISO contains too much high frequency waves, leading to the underestiniation of ISO intensity due to the dispersion of ISO energy. However, FGOALS-1.0g captured the salient features of ISO under the global warming background by two contrast experiments, such as the vitality and frequency-increasing of ISO in the central Indian Ocean and the Bay of Bengal.
