摘要
利用国际耦合模式比较计划第五阶段(CMIP5)26个模式的模拟结果,从空间分布和振幅变化、年际周期及年代际趋势等方面,初步评估了CMIP5模式对西太平洋副热带高压(副高)的模拟能力。在此基础上,还对未来不同典型浓度路径(RCPs)情景下副高的可能变化给出了定性的预估。CMIP5模式历史试验结果显示,大多数模式对500 hPa位势高度气候平均值的模拟有明显误差,这主要是由于模式对热带印度洋和西太平洋地区海表温度(SST)的模拟普遍较观测值低,从而导致模式对副高的模拟能力有限。但大多数模式对高度场和纬向风场变化的空间形态与振幅都有较强的模拟能力。因此,通过用NCEP/NCAR再分析资料的气候平均值替代CMIP5模式气候平均值的简单方法,对CMIP5模拟结果进行了订正。经订正后的模式结果均有能力刻画副高指数的历史时间序列,且能够反映出20世纪70年代末期之后,副高面积增大、强度增强和显著西伸的变化趋势。此外,通过对副高指数的长期趋势、年际周期及标准差等的定量评估,注意到CNRM-CM5、FGOALSg2、FIO-ESM,MIROC-ESM和MPI-ESM-P这5个模式对副高的模拟能力较强。未来气候预估试验中,副高面积和强度均增大,且显著西伸;其线性增长趋势在RCP8.5情景下最高,RCP4.5情景下次之,RCP2.6情景下最弱。有趣的是副高脊线指数在3种排放情景下都没有明显的长期变化趋势。这些结果为选取和利用CMIP5模式进行东亚地区气候变化的归因分析和未来预估提供了一定的科学依据。
This work examined the performance of 26 coupled climate models participating in the Coupled Model Intercompari-son Project Phase 5 （CMIP5）in the simulation of the present-day temporal variability and spatial pattern of the western Pacific subtropical high （WPSH）.Results show that most models are able to capture the spatial distribution and variability of the 500 hPa geopotential height and zonal wind fields in the western subtropical Pacific,with the underestimation of the mean intensi-ties of WPSH.The underestimation may be associated with the cold bias of sea surface temperature in the tropical Indian and western Pacific Oceans in the models.To eliminate the impact of the climatology biases,the climatology of these models is re-placed by that of the NCEP/NCAR reanalysis in the verification.It is noted that at interdecadal time scales,the models repro-duce the shift of WPSH with enhancement and westward extension after the late 1970s.According to assessment of the simula-tions of the WPSH indices,it is found that some models （CNRM-CM5,FGOALS-g2,FIO-ESM,MIROC-ESM and MPI-ESM-P）are better than others in simulating WPSH.Then the ensemble mean of these better models are used to project the fu-ture changes of WPSH under three typical Representation Concentration Pathway scenarios （RCP8.5,RCP4.5,RCP2.6）.It is suggested that the WPSH enlarges and strengthens,and its position extends westward under the scenarios,with the largest linear growth trend in RCP8.5,smallest in RCP2.6,and in between in RCP4.5;while the ridge line of WPSH does not show obvious long-term trend.These results may have implications for the attribution and prediction of climate variations and chan-ges in East Asia.
出处
《气象学报》
CAS
CSCD
北大核心
2014年第2期277-290,共14页
Acta Meteorologica Sinica
基金
国家重点基础研究发展计划(2010CB950501
2013CB430202)
国家自然科学基金项目(41005037)
公益性行业(气象)科研专项(GYHY201306024
GYHY20130633)
