The NCEP-NCAR reanalysis dataset and the HadlSST dataset （1959-2014） are used to analyze the impact of two types of E1 Nino events, i.e., eastern Pacific E1 Nino （EP-E1 Nino） and central Pacific E1 Nino （CP-E1 N...The NCEP-NCAR reanalysis dataset and the HadlSST dataset （1959-2014） are used to analyze the impact of two types of E1 Nino events, i.e., eastern Pacific E1 Nino （EP-E1 Nino） and central Pacific E1 Nino （CP-E1 Nino） events, on the duration of major and minor sudden stratospheric warmings （SSWs） in Northern Hemisphere winter （November to February）. Al- though the frequency of major and minor SSWs during different types of E1 Nino shows no distinct differences, the duration of both major and minor SSWs during CP-E1 Nino is shorter than that during EP-E1 Nino. The spatial distribution of geopo- tential height anomalies preceding major SSWs resembles the western Pacific （WP） teleconnection pattern, while the spatial distribution of geopotential height anomalies preceding minor SSWs bears similarity to the Pacific-North America （PNA） teleconnection pattern. An enhancement of the strength of both wavenumber 1 and wavenumber 2 is found before major SSWs. Before minor SSWs, wavenumber 1 is also strengthened, but wavenumber 2 is weakened. The analysis also reveals that EP-E1 Nino tends to induce positive phases of PNA and WP teleconnections, while CP-E1 Nino induces negative-phase WP teleconnection. As the positive phases of the PNA and WP teleconnections are related to the strengthening of wavenum- bet 1, EP-E1 Nino causes an enhancement of wavenumber 1 in the high-latitude upper troposphere and an enhancement of the upward wave flux in the high-latitude stratosphere, accompanied by a negative anomaly in Eliassen-Palm flux divergence in the subpolar stratosphere, which accounts for the longer SSW duration during EP-E1 Nino than during CP-E1 Nino.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 41225018 and 41575038)
文摘The NCEP-NCAR reanalysis dataset and the HadlSST dataset （1959-2014） are used to analyze the impact of two types of E1 Nino events, i.e., eastern Pacific E1 Nino （EP-E1 Nino） and central Pacific E1 Nino （CP-E1 Nino） events, on the duration of major and minor sudden stratospheric warmings （SSWs） in Northern Hemisphere winter （November to February）. Al- though the frequency of major and minor SSWs during different types of E1 Nino shows no distinct differences, the duration of both major and minor SSWs during CP-E1 Nino is shorter than that during EP-E1 Nino. The spatial distribution of geopo- tential height anomalies preceding major SSWs resembles the western Pacific （WP） teleconnection pattern, while the spatial distribution of geopotential height anomalies preceding minor SSWs bears similarity to the Pacific-North America （PNA） teleconnection pattern. An enhancement of the strength of both wavenumber 1 and wavenumber 2 is found before major SSWs. Before minor SSWs, wavenumber 1 is also strengthened, but wavenumber 2 is weakened. The analysis also reveals that EP-E1 Nino tends to induce positive phases of PNA and WP teleconnections, while CP-E1 Nino induces negative-phase WP teleconnection. As the positive phases of the PNA and WP teleconnections are related to the strengthening of wavenum- bet 1, EP-E1 Nino causes an enhancement of wavenumber 1 in the high-latitude upper troposphere and an enhancement of the upward wave flux in the high-latitude stratosphere, accompanied by a negative anomaly in Eliassen-Palm flux divergence in the subpolar stratosphere, which accounts for the longer SSW duration during EP-E1 Nino than during CP-E1 Nino.
