MJO与中国冬季气候的关系及全球变暖背景下MJO的可能影响
发布时间：2019-06-20 18:22
【摘要】：基于1951-2011年中国756站点气温、降水资料、NCEP/NCAR再分析大气资料、1998-2012年TRMM卫星降水资料以及CMIP5多模式输出结果,本文分析MJO频率以及强度的年际变化特征,揭示MJO年际变化与中国冬季气候的关系,探讨全球变暖背景下它的可能变化以及对中国区域气候的影响。主要结论如下:(1)MJO频率和强度的年际变化对中国温度降水的影响利用 Wheeler 和 Hendon(2004)定义的 RMM 指数,分析 1979/1980-2012/2013期间冬季MJO与我国冬季降水和气温变化的关系。结果表明,伴随MJO对流中心沿赤道东传时,我国长江流域和华南地区经历了降水异常增多到异常减少的过程。而全国气温经历了降温再增温的演变。分析MJO频率的年际变化与中国冬季气温、降水关系可以发现,对流中心出现在印度洋区域的频率增加引起我国华南地区冬季降水增多、冬季气温显著降低,同时引起东北地区降水偏少。MJO在海洋性大陆及赤道西太平洋频率增加引起我国内陆部分地区降水减少以及南方的冬季气温显著上升。就强度变化而言,MJO各位相的一致性增强(减弱)对我国冬季降水及气温的影响相对较小。而当MJO在赤道西太平洋区域强度增强,印度洋地区强度减弱时,中国长江流域的冬季降水会显著减少,而西南地区的冬季气温显著降低。(2)模式对MJO模拟能力的评估为了研究MJO在全球变暖背景下的可能变化,本文评估了 CMIP5中14个模式对于MJO周期和移动的模拟能力。大多数模式在模拟MJO东传特征方面都存在一定的不足。虽然有些模式,如MRI-CGCM3以及GFDL-CM在海洋性大陆以及赤道西太平洋区域能够很好地表现MJO东传特征,但在赤道印度洋区域却表现为无传播的静止状态,这很有可能是因为在这些模式中,MJO的向东传播过程并不是源自印度洋经过海洋性大陆最终到达西太平洋的过程所致。而CNRM-CM5模式在印度洋、海洋性大陆、西太平洋三个区域内对MJO东传的模拟性能最好。通过波数能量谱的分析发现,与观测结果相比,除了 CRNM-CM5模式较好模拟出MJO的1-3波为主的特征外,绝大多数模式的波数能量谱中,MJO的能量都非常弱,也不能体现1-3个波的能量大值区,故而都无法很好地模拟出 MJO。(3)全球变暖背景下MJO的可能变化以及其对中国冬季气候的影响通过CMRM-CM5模式中的Pre-industrial试验与高排放情景RCP85试验相对比发现,当全球气候增暖,MJO的强度将明显增强,周期缩短,纬向波数由1-3波为主转变为1-2波为主。对比分析两个试验中全球以及中国地区冬季降水场和温度场差异发现,在全球气候增暖的背景下,MJO在第3位相频数增多,在第7、第8位相强度增强。总体而言,气候变暖背景下MJO的变化对冬季长江流域降水增加,华南地区降水减少有贡献。对于气温来说,MJO的变化引起我国大部分地区气温负异常,特别对长江流域和华北的部分地区冬季温度降低有贡献。
[Abstract]:Based on the temperature and precipitation data of 756 stations in China from 1951 to 2011, NCEP/NCAR reanalysis atmospheric data, TRMM satellite precipitation data from 1998 to 2012 and CMIP5 multi-mode output results, this paper analyzes the interannual variation characteristics of MJO frequency and intensity, reveals the relationship between MJO interannual variation and winter climate in China, and discusses its possible changes under the background of global warming and its influence on regional climate in China. The main conclusions are as follows: (1) the influence of interannual variation of MJO frequency and intensity on temperature precipitation in China using the RMM index defined by Wheeler and Hendon (2004) to analyze the relationship between winter MJO and winter precipitation and temperature variation in China during 1979 / 1980 / 2012 / 2013. The results show that with the eastward propagation of MJO convective center along the equator, the Yangtze River Basin and South China experienced the process of abnormal increase of precipitation to abnormal decrease. The national temperature has experienced the evolution of cooling and increasing temperature. By analyzing the relationship between the interannual variation of MJO frequency and winter temperature in China, it can be found that the increase of the frequency of convective center in the Indian Ocean leads to the increase of winter precipitation and the decrease of winter temperature in South China, as well as the decrease of precipitation in Northeast China. The increase of MJO frequency in the oceanic continent and the equatorial western Pacific leads to the decrease of precipitation in some inland areas of China and the significant increase of winter temperature in the south of China. As far as the intensity change is concerned, the consistency of MJO phases has little effect on winter precipitation and temperature in China. When the intensity of MJO increases in the equatorial western Pacific and weakens in the Indian Ocean, the winter precipitation in the Yangtze River Basin of China will decrease significantly, while the winter temperature in southwest China will decrease significantly. (2) in order to study the possible changes of MJO in the background of global warming, the simulation ability of 14 models in CMIP5 for MJO cycle and movement is evaluated in this paper. Most of the models have some shortcomings in simulating the eastward transmission characteristics of MJO. Although some models, such as MRI-CGCM3 and GFDL-CM, can well express the eastward propagation characteristics of MJO in the oceanic continent and the equatorial western Pacific region, they exhibit a static state of no propagation in the equatorial Indian Ocean region, which may be due to the fact that the eastward propagation of MJO in these models is not due to the fact that the Indian Ocean finally reaches the western Pacific through the oceanic continent. The CNRM-CM5 model has the best simulation performance of MJO eastward in the Indian Ocean, oceanic continent and western Pacific. Through the analysis of wavenumber energy spectrum, it is found that, compared with the observed results, except that the CRNM-CM5 model can better simulate the 1 鈮，
本文编号：2503429
[Abstract]:Based on the temperature and precipitation data of 756 stations in China from 1951 to 2011, NCEP/NCAR reanalysis atmospheric data, TRMM satellite precipitation data from 1998 to 2012 and CMIP5 multi-mode output results, this paper analyzes the interannual variation characteristics of MJO frequency and intensity, reveals the relationship between MJO interannual variation and winter climate in China, and discusses its possible changes under the background of global warming and its influence on regional climate in China. The main conclusions are as follows: (1) the influence of interannual variation of MJO frequency and intensity on temperature precipitation in China using the RMM index defined by Wheeler and Hendon (2004) to analyze the relationship between winter MJO and winter precipitation and temperature variation in China during 1979 / 1980 / 2012 / 2013. The results show that with the eastward propagation of MJO convective center along the equator, the Yangtze River Basin and South China experienced the process of abnormal increase of precipitation to abnormal decrease. The national temperature has experienced the evolution of cooling and increasing temperature. By analyzing the relationship between the interannual variation of MJO frequency and winter temperature in China, it can be found that the increase of the frequency of convective center in the Indian Ocean leads to the increase of winter precipitation and the decrease of winter temperature in South China, as well as the decrease of precipitation in Northeast China. The increase of MJO frequency in the oceanic continent and the equatorial western Pacific leads to the decrease of precipitation in some inland areas of China and the significant increase of winter temperature in the south of China. As far as the intensity change is concerned, the consistency of MJO phases has little effect on winter precipitation and temperature in China. When the intensity of MJO increases in the equatorial western Pacific and weakens in the Indian Ocean, the winter precipitation in the Yangtze River Basin of China will decrease significantly, while the winter temperature in southwest China will decrease significantly. (2) in order to study the possible changes of MJO in the background of global warming, the simulation ability of 14 models in CMIP5 for MJO cycle and movement is evaluated in this paper. Most of the models have some shortcomings in simulating the eastward transmission characteristics of MJO. Although some models, such as MRI-CGCM3 and GFDL-CM, can well express the eastward propagation characteristics of MJO in the oceanic continent and the equatorial western Pacific region, they exhibit a static state of no propagation in the equatorial Indian Ocean region, which may be due to the fact that the eastward propagation of MJO in these models is not due to the fact that the Indian Ocean finally reaches the western Pacific through the oceanic continent. The CNRM-CM5 model has the best simulation performance of MJO eastward in the Indian Ocean, oceanic continent and western Pacific. Through the analysis of wavenumber energy spectrum, it is found that, compared with the observed results, except that the CRNM-CM5 model can better simulate the 1 鈮，
本文编号：2503429
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