MJO與中國冬季氣候的關(guān)系及全球變暖背景下MJO的可能影響
發(fā)布時間：2019-06-20 18:22
【摘要】：基于1951-2011年中國756站點氣溫、降水資料、NCEP/NCAR再分析大氣資料、1998-2012年TRMM衛(wèi)星降水資料以及CMIP5多模式輸出結(jié)果,本文分析MJO頻率以及強度的年際變化特征,揭示MJO年際變化與中國冬季氣候的關(guān)系,探討全球變暖背景下它的可能變化以及對中國區(qū)域氣候的影響。主要結(jié)論如下:(1)MJO頻率和強度的年際變化對中國溫度降水的影響利用 Wheeler 和 Hendon(2004)定義的 RMM 指數(shù),分析 1979/1980-2012/2013期間冬季MJO與我國冬季降水和氣溫變化的關(guān)系。結(jié)果表明,伴隨MJO對流中心沿赤道東傳時,我國長江流域和華南地區(qū)經(jīng)歷了降水異常增多到異常減少的過程。而全國氣溫經(jīng)歷了降溫再增溫的演變。分析MJO頻率的年際變化與中國冬季氣溫、降水關(guān)系可以發(fā)現(xiàn),對流中心出現(xiàn)在印度洋區(qū)域的頻率增加引起我國華南地區(qū)冬季降水增多、冬季氣溫顯著降低,同時引起東北地區(qū)降水偏少。MJO在海洋性大陸及赤道西太平洋頻率增加引起我國內(nèi)陸部分地區(qū)降水減少以及南方的冬季氣溫顯著上升。就強度變化而言,MJO各位相的一致性增強(減弱)對我國冬季降水及氣溫的影響相對較小。而當MJO在赤道西太平洋區(qū)域強度增強,印度洋地區(qū)強度減弱時,中國長江流域的冬季降水會顯著減少,而西南地區(qū)的冬季氣溫顯著降低。(2)模式對MJO模擬能力的評估為了研究MJO在全球變暖背景下的可能變化,本文評估了 CMIP5中14個模式對于MJO周期和移動的模擬能力。大多數(shù)模式在模擬MJO東傳特征方面都存在一定的不足。雖然有些模式,如MRI-CGCM3以及GFDL-CM在海洋性大陸以及赤道西太平洋區(qū)域能夠很好地表現(xiàn)MJO東傳特征,但在赤道印度洋區(qū)域卻表現(xiàn)為無傳播的靜止狀態(tài),這很有可能是因為在這些模式中,MJO的向東傳播過程并不是源自印度洋經(jīng)過海洋性大陸最終到達西太平洋的過程所致。而CNRM-CM5模式在印度洋、海洋性大陸、西太平洋三個區(qū)域內(nèi)對MJO東傳的模擬性能最好。通過波數(shù)能量譜的分析發(fā)現(xiàn),與觀測結(jié)果相比,除了 CRNM-CM5模式較好模擬出MJO的1-3波為主的特征外,絕大多數(shù)模式的波數(shù)能量譜中,MJO的能量都非常弱,也不能體現(xiàn)1-3個波的能量大值區(qū),故而都無法很好地模擬出 MJO。(3)全球變暖背景下MJO的可能變化以及其對中國冬季氣候的影響通過CMRM-CM5模式中的Pre-industrial試驗與高排放情景RCP85試驗相對比發(fā)現(xiàn),當全球氣候增暖,MJO的強度將明顯增強,周期縮短,緯向波數(shù)由1-3波為主轉(zhuǎn)變?yōu)?-2波為主。對比分析兩個試驗中全球以及中國地區(qū)冬季降水場和溫度場差異發(fā)現(xiàn),在全球氣候增暖的背景下,MJO在第3位相頻數(shù)增多,在第7、第8位相強度增強�？傮w而言,氣候變暖背景下MJO的變化對冬季長江流域降水增加,華南地區(qū)降水減少有貢獻。對于氣溫來說,MJO的變化引起我國大部分地區(qū)氣溫負異常,特別對長江流域和華北的部分地區(qū)冬季溫度降低有貢獻。
[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，
本文編號：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，
本文編號：2503429
本文鏈接：http://sikaile.net/shoufeilunwen/benkebiyelunwen/2503429.html
最近更新
教材專著
