南海环境要素的年际变化与1982—1983年EI Nio

本文在大量调查资料的基础上,分析了1975—1984年南海环境要素的年际变化及其在1982—1983年的表现。研究发现,与正常年份比较,各要素在1982—1983年的表现都比较特殊,沿岸江河径流量猛增;气温、水温、盐度、pH值偏低;海水含氧量偏高,温、盐、密跃层强度增大;南海暖流和黑潮南海分支流轴的平均位置移到调查海区的最南面。作者认为,这一异常现象与1982—1983年赤道太平洋海域发生的强E1 Ni(?)o过程密切相关。     

耦合海气动力学短期变率的数值研究

为了探索全球性气候变化的年际变率，研制了一个复盖热带太平洋区域的耦合海气模式，并用来模拟ＥＮＳＯ变率的主要特征。数值试验结果与实况比较表明，对１９８２／１９８３年厄尔尼诺事件的主要特征模拟良好。基本结论是要考虑好关键要素和关键过程，即：平均风场和平均海温场；风和海温场的年循环；海洋表面层；三维海温平流；大气（水平方向）水汽辐合效应。     

NON-LINEAR CRITICAL LAYER IN EL NINO AND LA NINA YEARS AND FORMATION, MAINTENTENANCE AND OSCILLATION OF THE SUBTROPICAL HIGH

Monthly mean zonal wind data from the European Center for Medium-range Weather Forecasting(ECMWF)for December 1982, April 1983, October 1984 and ApriI 1985 are used in numerical integration as thebasic flow in a non-linear critical-layer model. The subtropical high is extensive and limited in number if simulated with the basic now in December 1982 and April 1983. It consists of 2 to 3 cells that move westward at alloscillatory periods of 1～2 months. The subtropical high, simulated with the basic flow in October 1984 and April1 985. is weak and small in coverage, or distributed in strips that contain up to 4 cells. The high. merged or spillover a short time. is moving westward. The years 1982 ～1983 are a process of EI Niño while the years 1984-1985one of La Niña. lt is known from the chart of energy flux that it oscillates by a much larger amplitude and longerperiod in the EI Niño year than in the La Niña year. All the results above have indicated that the basic flow in the EI Niño year is enhancing the subtropical high lagging by about 4 months and that in the La Niña year is decay'ing it. It is consiStent with the well-known observational fact that the SSTA in the equatorial eastern Pacitlc ispositively correlated with the extent and intensity of the subtropical high in west Pacific lagging by 1～2 seasons.The result is also important for further study of the formation, maintenance and oscillation of the subtropicalhigh.     

TYPHOON ACTIVITY IN NORTHWEST PACIFIC IN RELATION WITH EL NINO AND LA NINA EVENTS

Statistic and typical-year composition methods are used to study the northwest Pacific typhoon activities in relation with the EI Niño and La Niña events. The result indicates that the typhoon tends to be inactive in the EI Niño years and active in the La Niña years and it is also dependent on the onset and ending time and intensity of the events and areas of genesis of typhoons. With statistic features of the frequency of typhoon activity in the EI Niño and La Niña years and the time-lag correlation between the frequency and sea surface temperature(SST), useful information is provided for the prediction of typhoon occurrence. In addition, the singular values disassemble(SVD)method is applied to study the correlation between the geopotential field and SST field. The result shows that the air-sea coupling in the EI Niño years is unfavorable for the typhoon to develop. Which take place with a smaller number. Opposite situations are found with the La Niña years.     

基于CLDAS融合降水的中国降雨侵蚀力研究

气象站和卫星降雨资料估算降雨侵蚀力时存在无法反映空间异质性且精度差的问题,基于CLDAS多源融合降水,利用EI₆₀模型从不同的时空尺度对中国的降雨侵蚀力进行评估,并结合降雨量、侵蚀性降雨次数、侵蚀密度等指标,探讨降雨对土壤侵蚀的潜在作用。结果表明：（1） CLDAS降雨侵蚀力与地面实测数据在不同的时间尺度均有良好的回归关系,相关系数达到0.8以上,与CMORPH降雨侵蚀力相比,其相对误差显著降低,可以准确反映全国范围的降雨侵蚀力季节性变异。（2） 在2001—2020年,不同雨量区的降雨侵蚀力、降雨量和侵蚀性降雨次数的变化趋势基本一致,高雨量区的年际变化波动剧烈,侵蚀性降雨次数和暴雨过程协同影响降雨侵蚀力的大小。（3） 空间上,中国的降雨侵蚀力值的特点为东南沿海地区高、西北内陆地区低。时间上,侵蚀性降雨集中在5—8月,夏、秋两季对土壤造成的侵蚀影响更大。（4） 通过对年降雨量、年侵蚀密度和年暴雨量进行分区定量分析,结果表明暴雨量与侵蚀密度成正相关关系,即年降雨量一定,暴雨事件越多,降雨侵蚀密度越大。     

舟山冬季暴雨的特征

文章分析了冬季暴雨发生时的环流形势和物理量场分布特征,揭示了冬季暴雨的发生与厄尔尼诺现象有着一定的相关。同时,分析了单站要素的变化,为以后的冬季暴雨预报提供参考。     

全球变化背景下新疆地区气候跃变的可能影响因素分析

基于新疆过去50a气温和降水时间序列长期趋势的研究结果,结合对1986年及附近时段对全球气候产生重大影响的一系列事件（厄尔尼诺、火山爆发、核电站爆炸事故、温室气体增加等）的分析,探讨了1986年新疆气温和降水出现跳跃式变化的原因.具体表现为：当厄尔尼诺现象发生时,常常出现暖冬、早春,在该现象消退过程,往往降水有所增多;...     

东亚冬季风活动与厄·尼诺的关系

本文利用1951—1986年全球月平均海平面气压资料以及赤道东太平洋的海温资料,研究了东亚冬季风的年际变化与厄·尼诺的关系,主要结果有:(1)东亚冬季风盛行期(10—3)赤道东太平洋海温与海平面气压场的密切相关区,主要位于亚洲南部和西太平洋(正相关)、澳洲北部(正相关)以及阿留申群岛地区(负相关)。(2)海温的变化一般超前冬季风的变化1—2个季节,以11月的海温与之相关最密切。(3)厄·尼诺年冬季,东亚大陆冷空气南下路径偏东,我国南方多雨。反厄·尼诺年相反,冷空气南下路径偏西,我国南方少雨。     

太平洋海面粗糙度的计算及在ENSO期间的变化

利用TOPEX高度计风速资料,实现了对太平洋海面粗糙度(z0)的计算。1997~1999年正是厄尔尼诺与拉尼娜事件发生时期,作者研究了1997~1999年z0在ENSO期间的变化后发现:(1)EI Nion发生期间赤道附近z0最大值在A,C,B 3个站点上移动;最小值在B,A 2个站点上移动。(2)Li Nina发生期间赤道附近z0最小值在A站点,最大值主要在B站点上。Li Nina发生期间,1999年15个站点z0均大于正常年份和EI Nion发生期间的15个站点z0。(3)ENSO期间,四季z0与正常年份相比都有显著改变。     

EL NINO EPISODE-RELATED NH 100 hpa CIRCULATION ANOMALY

Investigation is carried out of winter Northern Hemisphere (NH) 100 hpa teleconnection, indicating the existence of a PNA pattern whose wavetrain well resembles that at 500 hpa level. During the climax of the EI Nino episode (winter), the 100 PNA becomes strong, a fact that manifests itself more clearly than at the 500 hpa level. Moreover, study is made of the anomaly in the tropical monthly windfield and mean circulation on a seasonal basis in a range of phases of the EI Nino event. Results show that the 100 hpa geopotential height is lowered on a large scale in the spring and previous winter with the event happening as compared to a La Nina year, wherewith diagnosis is performed of the 1991/1992 EI Nino episode.