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
The responses of the climate system to increase of atmospheric carbon dioxide(CO_2)are studied by using a new version of the Bureau of Meteorological Research Centre(BMRC)global coupled general circulation model(CGCM)...The responses of the climate system to increase of atmospheric carbon dioxide(CO_2)are studied by using a new version of the Bureau of Meteorological Research Centre(BMRC)global coupled general circulation model(CGCM).Two simulations are run:one with atmospheric CO_2 concentration held constant at 330 ppm,the other with a tripling of atmospheric CO_2(990 ppm). Results from the 41-year control coupled integration are applied to analyze the mean state, seasonal cycle and interannual variability in the model.Comparisons between the greenhouse experiment and the control experiment then provide estimations of the influence of increased CO_2 on climate changes and climate variability.Especially discussed is the question on whether the climate changes concerned with CO_2 inerease will impact interannual variability in tropical Pacific, such as ENSO.展开更多
Based on an analysis of the relationship between the tropical cyclone genesis frequency and large-scale circulation anomaly in NCEP reanalysis, large-scale atmosphere circulation information forecast by the JAMSTEC SI...Based on an analysis of the relationship between the tropical cyclone genesis frequency and large-scale circulation anomaly in NCEP reanalysis, large-scale atmosphere circulation information forecast by the JAMSTEC SINTEX-F coupled model is used to build a statistical model to predict the cyclogenesis frequency over the South China Sea and the western North Pacific. The SINTEX-F coupled model has relatively good prediction skill for some circulation features associated with the cyclogenesis frequency including sea level pressure, wind vertical shear, Intertropical Convergence Zone and cross-equatorial air flows. Predictors derived from these large-scale circulations have good relationships with the cyclogenesis frequency over the South China Sea and the western North Pacific. A multivariate linear regression(MLR) model is further designed using these predictors. This model shows good prediction skill with the anomaly correlation coefficient reaching, based on the cross validation, 0.71 between the observed and predicted cyclogenesis frequency. However, it also shows relatively large prediction errors in extreme tropical cyclone years(1994 and 1998, for example).展开更多
Predictions of ENSO are described by using a coupled atmosphere-ocean general circulation model. The initial conditions are created by forcing the coupled system using SST anomalies in the tropical Pacific at the back...Predictions of ENSO are described by using a coupled atmosphere-ocean general circulation model. The initial conditions are created by forcing the coupled system using SST anomalies in the tropical Pacific at the background of the coupled model climatology. A series of 24-month hindcasts for the period from November 1981 to December 1997 are carried out to validate the performance of the coupled system. Correlations of SST anomalies in the Nino3 region exceed 0.54 up to 15 months in advance and the rms errors are less than 0.9℃. The system is more skillful in predicting SST anomalies in the 1980s and less in the 1990s. The model skills are also seasonal-dependent, which are lower for the predictions starting from late autumn to winter and higher for those from spring to autumn in a year-time forecast length. The prediction, beginning from March, persists & months long with the correlation skill exceeding 0.6, which is important in predictions of summer rainfall in China. The predictions are succesful in many aspects for the 1997-2000 ENSO events.展开更多
The world is facing a big challenge of climatic change, mainly due to increasing concentrations of GHGs （greenhouse gases） in the atmosphere. Many researches indicated that the climate change occurred disproportiona...The world is facing a big challenge of climatic change, mainly due to increasing concentrations of GHGs （greenhouse gases） in the atmosphere. Many researches indicated that the climate change occurred disproportionately on developing countries such as MENA （Middle East and North Africa） countries. The climatic model CGCM3.1 （T47） 2 is used in this research to explain the changes in average temperatures and the rainfall on the MENA region with special emphases on Iraq. Historical records （1900-2009） and future （2020-2099） were studied and compared; each period was divided to four sub-periods of thirty years. The results showed that the average monthly temperature for the four historical periods fluctuated between the lowest and highest value as follows： 9.2-32.9, 10.3-32.7, 9.3-32.8 and 8.6-33.9 （℃）. The rainfall for historical periods kept on the same distribution during the past 109 years, and fluctuated between the lowest and highest value of 21.3 mm and 37.6 mm with an average that reached up to 26.51 mm. For the future period, the maximum average monthly temperature reached up to 37.41 （℃） during June and minimum average monthly temperature reached up to 4.24 （℃） during January. The average monthly temperature fluctuated giving a clear impression that the future portends a higher temperature. The average monthly rainfall, for the future period, fluctuated between the lowest and highest value of 12.91 mm and 20.63 mm with an average that reached 16.84 mm which represent a reduction percentage of about 36.47% relative to the historical record of rainfall for the sanae months.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.
文摘The responses of the climate system to increase of atmospheric carbon dioxide(CO_2)are studied by using a new version of the Bureau of Meteorological Research Centre(BMRC)global coupled general circulation model(CGCM).Two simulations are run:one with atmospheric CO_2 concentration held constant at 330 ppm,the other with a tripling of atmospheric CO_2(990 ppm). Results from the 41-year control coupled integration are applied to analyze the mean state, seasonal cycle and interannual variability in the model.Comparisons between the greenhouse experiment and the control experiment then provide estimations of the influence of increased CO_2 on climate changes and climate variability.Especially discussed is the question on whether the climate changes concerned with CO_2 inerease will impact interannual variability in tropical Pacific, such as ENSO.
基金Specialized Science and Technology Project for Public Welfare Industry(GYHY200906015)National Basic Research Program of China(973 Program,2010CB428606)Key Technologies R&D Program of China(2009BAC51B05)
文摘Based on an analysis of the relationship between the tropical cyclone genesis frequency and large-scale circulation anomaly in NCEP reanalysis, large-scale atmosphere circulation information forecast by the JAMSTEC SINTEX-F coupled model is used to build a statistical model to predict the cyclogenesis frequency over the South China Sea and the western North Pacific. The SINTEX-F coupled model has relatively good prediction skill for some circulation features associated with the cyclogenesis frequency including sea level pressure, wind vertical shear, Intertropical Convergence Zone and cross-equatorial air flows. Predictors derived from these large-scale circulations have good relationships with the cyclogenesis frequency over the South China Sea and the western North Pacific. A multivariate linear regression(MLR) model is further designed using these predictors. This model shows good prediction skill with the anomaly correlation coefficient reaching, based on the cross validation, 0.71 between the observed and predicted cyclogenesis frequency. However, it also shows relatively large prediction errors in extreme tropical cyclone years(1994 and 1998, for example).
基金Key Program of Chinese Academy of Sciences KZCXZ-203NationalKey Program for Developing Basic Sciences G1999032801Nationa
文摘Predictions of ENSO are described by using a coupled atmosphere-ocean general circulation model. The initial conditions are created by forcing the coupled system using SST anomalies in the tropical Pacific at the background of the coupled model climatology. A series of 24-month hindcasts for the period from November 1981 to December 1997 are carried out to validate the performance of the coupled system. Correlations of SST anomalies in the Nino3 region exceed 0.54 up to 15 months in advance and the rms errors are less than 0.9℃. The system is more skillful in predicting SST anomalies in the 1980s and less in the 1990s. The model skills are also seasonal-dependent, which are lower for the predictions starting from late autumn to winter and higher for those from spring to autumn in a year-time forecast length. The prediction, beginning from March, persists & months long with the correlation skill exceeding 0.6, which is important in predictions of summer rainfall in China. The predictions are succesful in many aspects for the 1997-2000 ENSO events.
文摘The world is facing a big challenge of climatic change, mainly due to increasing concentrations of GHGs （greenhouse gases） in the atmosphere. Many researches indicated that the climate change occurred disproportionately on developing countries such as MENA （Middle East and North Africa） countries. The climatic model CGCM3.1 （T47） 2 is used in this research to explain the changes in average temperatures and the rainfall on the MENA region with special emphases on Iraq. Historical records （1900-2009） and future （2020-2099） were studied and compared; each period was divided to four sub-periods of thirty years. The results showed that the average monthly temperature for the four historical periods fluctuated between the lowest and highest value as follows： 9.2-32.9, 10.3-32.7, 9.3-32.8 and 8.6-33.9 （℃）. The rainfall for historical periods kept on the same distribution during the past 109 years, and fluctuated between the lowest and highest value of 21.3 mm and 37.6 mm with an average that reached up to 26.51 mm. For the future period, the maximum average monthly temperature reached up to 37.41 （℃） during June and minimum average monthly temperature reached up to 4.24 （℃） during January. The average monthly temperature fluctuated giving a clear impression that the future portends a higher temperature. The average monthly rainfall, for the future period, fluctuated between the lowest and highest value of 12.91 mm and 20.63 mm with an average that reached 16.84 mm which represent a reduction percentage of about 36.47% relative to the historical record of rainfall for the sanae months.
