太平洋环流速度减慢的原因

对南极气温资料、环南极海冰资料、太平洋海温资料、厄尔尼诺和拉尼娜资料的模拟验证，发现厄尔尼诺事件发生与德雷克海峡海冰减少在时间上有对应关系。南极半岛海冰减少是太平洋环流速度减慢的原因，德雷克海峡的海冰起重要作用。这一综合检验结果给出以日食—厄尔尼诺系数预测厄尔尼诺事件的有效性和准确性。两年周期的太平洋海温振荡使日食与厄尔尼诺之间存在12～24个月的位相差。     

赤道太平洋次表层海水温度异常的信号通道

应用热带太平洋上层XBT温度资料,分析探讨了西太平洋暖池区次表层海温冷暖异常信号的变化规律,揭示了影响西太平洋暖池区次表层海温冷变异常的信号通道。分析表明,西太平洋暖池区的次表层海温异常变冷与太平洋北赤道流的海温冷异常信号西传有重要关系。北赤道流的海温异常冷(暖)信号是沿温跃层由赤道中东太平洋潜沉向西太平洋暖池区传播,与西太平洋次表层海温异常(冷)暖信号向赤道中东太平洋传播构成了热带海洋信号的气旋式"环流通道"。在这一"环流通道"中,北赤道流的海温异常信号西传是导致西太平洋暖池区及西太平洋次表层海温异常的重要机制,是影响厄尔尼诺(ElNino)和拉尼娜(LaNina)事件发生的关键。     

近50年来ENSO与祁连山区气温降水和出山径流的对应关系

根据有关水文气象台、站的观测资料,分析了恩索(ENSO)与祁连山区气温、降水的对应关系,研究了祁连山区出山径流对厄尔尼诺(ElNino)现象响应.结果表明:ElNino现象对祁连山区的气温、降水和径流的影响随着发生时间和地段的不同而不同.ElNino现象发生之年,整个祁连山区均出现气温偏高、降水减少及径流偏枯的现象,尤以东段和中段最为明显.ElNino现象次年,祁连山区东段和中段气温偏高、降水减少及径流偏估的程度不如ElNino现象当年那样显著,而西段的气温、降水及径流与ElNino现象则无明显关系.     

The relationship between ENSO cycle and temperature, precipitation and runoff in the Qilian mountain area

El Nino and La Nina are the events concerned internationally. The corresponding relationship between El Nino events, temperature, precipitation and runoff in the Qilian mountain area are analyzed according to the date from the weather and the hydrometric stations in the area, the results show that effects of El Nino events to temperature, precipitation and runoff are different in the different time and zones. When El Nino occurs, temperature rises, but precipitation and runoff decrease in the whole Qilian mountain area, especially in the east and middle parts of the area. Temperature rises, precipitation and runoff still decrease in the eastern Qilian mountain area in the next year El Nino occurring, but decrease extent is fewer. There are not obvious relationship between temperature, precipitation and runoff with El Nino events in the western Qilian mountain area.     

太阳活动,El Nino对北京地区降雨的影响及预测

本文通过对北京地区１９００年以来雨量,气温与太阳活动,厄尔尼诺的相关处理分析,得出一种预测北京地区年雨量的数学模型,已准确预测了１９９６,１９９７年的年雨量,对１９９８年预测为７５０ｍｍ～８００ｍｍ。     

Changes in trophic flow structure of Independence Bay (Peru) over an ENSO cycle

During the strong warm El Niño (EN) that occurred in 1997/98, Independence Bay (14°S, Peru) showed a ca. 10 °C increase in surface temperatures, higher oxygen concentrations, and clearer water due to decreased phytoplankton concentrations. Under these quasi-tropical conditions, many benthic species suffered (e.g. macroalgae, portunid crabs, and polychaetes) while others benefited (e.g. scallop, sea stars, and sea urchins). The most obvious change was the strong recruitment success and subsequent proliferation of the scallop Argopecten purpuratus, whose biomass increased fiftyfold. To understand these changes, steady-state models of the bay ecosystem trophic structure were constructed and compared for a normal upwelling year (1996) and during an EN (1998), and longer-term dynamics (1996–2003) were explored based on time series of catch and biomass using Ecopath with Ecosim (EwE) software. Model inputs were based on surveys and landings data collected by the Instituto del Mar del Perú (IMARPE). Results indicate that while ecosystem size (total throughput) is reduced by 18% during EN, mainly as a result of decreased total primary production, benthic biomass remains largely unchanged despite considerable shifts in the dominant benthic taxa (e.g. scallops replace polychaetes as secondary consumers). Under normal upwelling conditions, predation by snails and crabs utilize the production of their prey almost completely, resulting in more efficient energy flow to higher trophic levels than occurs during EN. However during EN, the proliferation of the scallop A. purpuratus combined with decreased phytoplankton increased the proportion of directly utilized primary production, while exports and flows to detritus are reduced. The simulations suggest that the main cause for the scallop outburst and for the reduction in crab and macroalgae biomass was a direct temperature effect, whereas other changes are partially explained by trophic interactions. The simulations suggest that bottom-up effects largely control the system.     

1997~89年冬季大气环流变化及中国近海海区天气气候特征

1997～98年发生了近百年最强的厄尔尼诺现象,本文对1997～98年冬季(12～2月)500hpa环流特征、东亚温带气旋活动及天气特征进行了分析．同时也对多年厄尔尼诺过程、非厄尔尼诺过程相对应的大气环流及天气特征做了对比分析．研究表明,厄尔尼诺年北半球500hpa环流30°N以南低纬地区位势高度偏高中纬度的槽脊分布与多年平均有较大不同,东亚大相偏弱,同时北美大槽减弱,北太平洋高压也减弱,西风环流指数偏强,西太平洋副热带高压西伸明显,强度偏强。中国东部沿海气旋分布特征为北部偏少,南部明显偏多;降水为东部沿海地区偏多明显;气温为南部海区出现高温的机率较大。     

VARIATIONS OF 30—60 DAY OSCILLATION IN ATMOSPHERE BEFORE AND DURING 1982 EL NINO

By using the upper-wind data from July 1980 to June 1983,the variations of the low-frequency oscillation(LFO)in the atmosphere before and during 1982 El Nino have been investigated.Before the El Nino,the LFOpropagates from west to east over the equator of the Eastern Hemisphere and from east to west over 20°N.The eastward propagating LFO over the equator consists of zonal wavenumber 1 propagating eastward andzonal wavenumber 2 with a character of stationary wave.The oscillation of zonal wavenumber 2 can modulatethe oscillation strength.After the onset of the El Nino,the propagating directions of the LFO over the equatorand 20°N of the Eastern Hemisphere change to be westward and eastward,respectively.The LFO over thewestern Pacific weakens rapidly and one coming from middle and high latitudes propagates to the equator.From the phase compositions of streamline fields for the zonal wavenumber 1 of equatorial westward propa-gatirg LFO,it is found that the atmospheric heat source in the equator of the eastern Pacific(EEP)excites aseries of the equatorial cyclones and anticyclones which move northward and westward and form the westwardpropagating LFO over the equator.With the wavelength of 20000km,this kind of equatorial wave is similarto the mixing Rossby-gravity wave.In its westward and northward movement,the circulation in East Asiais modified.This may be the mechanism of the influence of El Nino on the climate of China.     

IAP/LASG海洋环流模式对风应力的响应

为了检验第三代IAP/LASG全球海洋环流模式在模拟20世纪80年代热带太平洋年际变化方面特别是ElNino和LaNina事件的能力,作者使用了三种风应力资料强迫该模式.然后,将模拟的海温同NCEP海洋同化资料相比较.分析表明,在赤道附近,模式对风应力的响应在SST分布、温跃层的描绘以及突出E1Nino和LaNina事件方面同NCEP海洋同化资料有许多共同点.然而,在描绘l0°N以北和l0°S以南的SST异常以及描写季节循环方面,响应是不够精确的.另外,模拟的温度异常滞后于NCEP海洋同化数据两个月左右.     

El Nino演变不同阶段东亚大气环流年际异常型的数值模拟

给定1948～1999年逐月变化的全球观测的海表温度分布，使用全球大气环流模式（CCM3/NCAR）模拟了大气对海表温度变化的响应，利用SVD和合成检验方法，分析了El Nino发展阶段夏季、成熟阶段冬季以及衰亡阶段夏季东亚大气环流的年际异常型.结果表明：El Nino发展阶段夏季，中国东北、朝鲜半岛以及日本海附近为高度负异常中心，西太平洋副高偏弱、偏东，东亚夏季风增强；El Nino成熟阶段冬季，东亚大槽加强，东亚北部冬季风加强；El Nino衰亡阶段夏季，西太平洋副高偏强、偏南、西伸，东亚夏季风减弱；El Nino事件在其衰亡阶段夏季与东亚大气环流异常的关系最紧密，其次是成熟阶段冬季，最后是发展阶段夏季.模拟的El Nino演变不同阶段东亚大气环流年际异常型易于解释以往研究中观测分析揭示的由El Nino造成的我国东部气温和降水异常型.