厄尔尼诺和反厄尔尼诺事件与西北太平洋台风活动

用统计相关和典型年合成方法分析了厄尔尼诺和反厄尔尼诺事件与西北太平洋台风活动的关系，指出厄尔尼诺年台风活动减少，反厄尔尼诺年台风活动增加，而且台风活动与厄尔尼诺、反厄尔尼诺事件起始和终止时间、强度、台风生成区域有关。利用厄尔尼诺和反厄尔尼诺年台风活动频数的统计特征，及台风频数与海温等要素的时滞相关关系，为台风频数的预测提供了有益的信息。还应用奇异值分解方法，分析了高度场和海温场的相关关系。结果表明，厄尔尼诺年海气耦合作用将造成不利于台风发展的环流条件，因此台风偏少，反厄尔尼诺年则出现相反的情况。     

A new scenario for the last magmatic eruption of La Soufrière of Guadeloupe (Lesser Antilles) in 1530 A.D. Evidence from stratigraphy radiocarbon dating and magmatic evolution of erupted products

La Soufrière of Guadeloupe is a dangerous volcano characterized over the last decade by moderate seismic and fumarolic unrest. In the last 15,000 years it has experienced phreatic and magmatic eruptions and unusually numerous flank collapse events sometimes associated with a magmatic eruption. We propose a new age of 1530 A.D. and a new eruptive scenario for the last magmatic eruption on the basis of a novel statistical analysis of radiocarbon age dates, and new field and geochemical data. This eruption is the only magmatic eruption likely to have occurred in Guadeloupe during the last 1400 years. The eruption mainly involved an andesitic magma which, in the first phase of the eruption, partially mixed with a slightly more differentiated magma stored in a small and shallow magma chamber. Ascent of magma to the surface generated a partial collapse of the hydrothermally altered edifice that increased the magma discharge and led to a sub-plinian phase with scoria fallout and column-collapse pyroclastic flows followed by near-vent pyroclastic scoria fountains. The eruption ended with growth of a lava dome. Our revised interpretation of the last magmatic eruption of La Soufrière constitutes the most likely key to a future magmatic eruption scenario for this volcano which displays strong evidence of unrest since 1992.     

Localised coherent response of the La Molina basin (Lima,Peru) to earthquakes,and future approaches suggested by Parkway basin (New Zealand) experience

Earthquake records from a 1984 temporary seismograph array set up in La Molina, Lima, Peru, are re-analysed. The array comprised eight three-component geophones; seven soil based and one rock based. Values of horizontal-to-vertical spectral ratio (HVSR) for two small earthquakes peaked at around 1.3 Hz. In one distant earthquake, four of the seven soil-based stations showed a peak at 1.25 Hz in soil-to-rock spectral ratio (SSR), the same dominant frequency observed during an aftershock of a damaging earthquake. Because this frequency is not compatible with the shear wave velocity profile attributed to La Molina, and because the spectral peak is confined to a small ground area, it is concluded that the peak is caused by a localised deposit of soft soil. Because the area associated with the spectral peak includes the area of great damage in 1974, it is concluded that coherent monochromatic behaviour is responsible for the damage.     

2004年厄尔尼诺事件的理论预测和实践检验

地球自转速度减慢、赤道东太平洋表层海温升高、日食-厄尔尼诺系数增大与厄尔尼诺事件发生时间在一切细节上有惊人的对应关系。这个综合检验结果给出了地球自转减速和日食-厄尔尼诺系数预测厄尔尼诺事件的有效性和准确性。2004年的弱厄尔尼诺已得到初步证实,2005年的拉尼娜有待检验。     

The 2020/21 Extremely Cold Winter in China Influenced by the Synergistic Effect of La Niña and Warm Arctic

In the first half of winter 2020/21,China has experienced an extremely cold period across both northern and southern regions,with record-breaking low temperatures set in many stations of China.Meanwhile,a moderate La Ni?a event which exceeded both oceanic and atmospheric thresholds began in August 2020 and in a few months developed into its mature phase,just prior to the 2020/21 winter.In this report,the mid?high-latitude large-scale atmospheric circulation anomalies in the Northern Hemisphere,which were forced by the negative phase of Arctic Oscillation,a strengthened Siberian High,an intensified Ural High and a deepened East Asian Trough,are considered to be the direct reason for the frequent cold surges in winter 2020/21.At the same time,the synergistic effect of the warm Arctic and the cold tropical Pacific(La Ni?a)provided an indispensable background,at a hemispheric scale,to intensify the atmospheric circulation anomalies in middle-to-high latitudes.In the end,a most recent La Ni?a prediction is provided and the on-coming evolution of climate is discussed for the remaining part of the 2020/21 winter for the purpose of future decision-making and early warning.     

中国登陆热带气旋与太平洋海表温度的关系

根据1951～2000年中国登陆热带气旋与厄尔尼诺年、拉尼娜年的关系分析,得到了一些重要认识：(1) 在厄尔尼诺年,中国登陆热带气旋数偏少;(2) 厄尔尼诺事件强度越大,中国登陆热带气旋数越少;(3) 厄尔尼诺事件的结束时间若超过5月1日,那么次年中国登陆热带气旋数偏少;(4) 中国登陆热带气旋数的特多年主要集中在拉尼娜年;(5) 在拉尼娜次年,中国登陆热带气旋数偏少;(6) 中国登陆热带气旋强度越大,在厄尔尼诺年出现机会越少;(7) 在厄尔尼诺年,中国初旋偏迟,终旋偏早。同时对其机理进行了探讨。     

1988年反厄尼诺（La Nia）事件的数值模拟

用中国科学院大气物理研究所高分辨率、自由表面热带海洋环流模式对厄尼诺／南方涛动（Ｅｌ／ＳｏｕｔｈｅｒｎＯｓｃｉｌｌａｔｉｏｎ）循环中另一重要位相Ｌａ　事件进行了数值模拟研究。模式区域为南北纬３０°之间的热带太平洋，经纬圈水平方向分辨率分别为２°和１°，垂直方向分为不等距的１４层；模式中考虑了盐度并引入与洋流切变和层结稳定度有关的垂直扩散参数化方案。在观测到的海表风应力、热量和淡水通量（蒸发与降水之差）驱动下，所发展的模式从１９８４年积分到１９８９年。本文给出模式对近十几年来最强的１９８８年Ｌａ事件进行数值模拟的结果，着重分析Ｌａ期间热带太平洋海面起伏、流场和温度场时空演变，以及Ｌａ和Ｅｌ期间变量场时空结构差别。文中还进行了模式结果和一些观测资料间的比较。     

南印度洋偶极子的变化特征及其与ENSO事件的联系

利用Hadley Center逐月海温资料以及NCEP/NCAR逐月风场、海平面气压场等资料探讨了南印度洋偶极子(Southern Indian Ocean Dipole,SIOD)的变化特征及其与ENSO事件的联系。结果表明:1)发生在南半球副热带印度洋地区的海温异常西南—东北反相的南印度洋偶极子现象,具有明显的季节锁相特征:10—12月发生发展,次年1—3月发展成熟达到盛期,4—6月减弱消亡;SIOD的形成主要受大尺度大气环流的影响,马斯克林高压以及澳大利亚低(高)压位置和强度的变化引起的副热带印度洋海表面风场的异常,影响了海温的变化,进而形成SIOD。2)南半球副热带印度洋地区的海温变化与赤道中东太平洋地区海温异常密切联系,前冬ENSO事件与SIOD有显著的负相关关系,大多数正SIOD发生在La Ni?a事件之后,大多数负SIOD发生在El Ni?o事件之后;也存在部分SIOD事件的发生既不伴随La Ni?a现象,也不伴随El Ni?o现象。3)ENSO事件产生的异常垂直运动和赤道异常纬向风对南半球副热带印度洋地区的海平面气压以及海表面风场的强度和位置的变化有重要作用,可以分别影响SIOD东西极子的演变,进而对SIOD产生影响。4)SIOD事件也可单独发生,一般负事件比正事件早一个月发生,同时由于没有ENSO事件的作用,海温异常反相的现象不能持续,单独发生的SIOD事件生命期较短。     

近百年ElNino/LaNina事件与北京气候相关性分析

通过对近百年El Nino/La Nina事件与北京气候相关性研究发现，El Nino/La Nina事件与北京夏季（6－8月）降水、平均最高气温（7月）和冬季（1月）平均最低气温之间相互关系显著。El Nino事件与夏季降水、冬季平均最低气温呈负相关，与夏季平均最高气温呈正相关，造成降水减少，气温年较差较大，大陆性增强的气候特点。La Nina事件与夏季降水、冬季平均最低气温呈正相关，与夏季平均最高气温呈负关，使降水增加，气温年较差减小，大陆性减弱的气候特点。