Possible Impacts of the Arctic Oscillation on the Interdecadal Variation of Summer Monsoon Rainfall in East Asia

The influences of the wintertime AO (Arctic Oscillation) on the interdecadal variation of summer monsoon rainfall in East Asia were examined. An interdecadal abrupt change was found by the end of the 1970s in the variation of the AO index and the leading principal component time series of the summer rainfall in East Asia, The rainfall anomaly changed from below normal to above normal in central China, the southern part of northeastern China and the Korean peninsula around 1978. However,the opposite interdecadal variation was found in the rainfall anomaly in North China and South China.The interdecadal variation of summer rainfall is associated with the weakening of the East Asia summer monsoon circulation. It is indicated that the interdecadal variation of the AO exerts an influence on the weakening of the monsoon circulation. The recent trend in the AO toward its high-index polarity during the past two decades plays important roles in the land-sea contrast anomalies and wintertime precipitation anomaly. The mid- and high-latitude regions of the Asian continent are warming, while the low-latitude regions are cooling in winter and spring along with the AO entering its high-index polarity after the late 1970s. In the meantime, the precipitation over the Tibetan Plateau and South China is excessive, implying an increase of soil moisture. The cooling tendency of the land in the southern part of Asia will persist until summer because of the memory of soil moisture. So the warming of the Asian continent is relatively slow in summer. Moreover, the Indian Ocean and Pacific Ocean which are located southward and eastward of the Asian land, are warming from winter to summer. This suggests that the contrast between the land and sea is decreased in summer. The interdecadal decrease of the land-sea heat contrast finally leads to the weakening of the East Asia summer monsoon circulation.     

春玉米农业气象观测资料在产量预报中的应用

通过分析1994~2003年来宾市农业气象观测的春玉米生育状况、春玉米地段土壤水分资料,建立春玉米农业气象观测资料与观测地段理论产量、来宾市兴宾区春玉米产量的模型,得出用观测资料预报产量较常规预报方法预报准确率有较大提高,为提高作物产量气象预报质量提供一种预报方法依据。     

河北怀来ML4.4地震前的地热异常

2002年8月3日15时57分在河北怀来发生了ML4．4地震，在震中距100km范围内的4个台站，三马坊、赤城、矾山、张家口台数字化地热观测均有一定的异常反映，其中，三马坊、赤城台有较明显的临震异常。介绍了各台的地热观测情况，利用差分法、减组合滤波等非潮汐方法进行了分析，指出，该震例总结对今后的地震监测和预报有一定的借鉴和参考作用。     

关于数字化记录中前兆信号的分析

介绍了如何用MATLAB工具软件—小波分析的基本理论对数字信号进行数字滤波,着重分析和研究了呼和浩特地震台形变观测资料出现各种信号,提出了小波分析理论对台站实际工作的重要性。     

认识自然灾害

火山学始于普林尼（Pliny）这位年轻人对公元前79年意大利维苏威火山毁灭性喷发的观察。1980年5月圣海伦斯火山的喷发及其结果则是第一次使用了各种不同的现代仪器进行系统观测和监测的火山喷发，从而促进了新监测仪器的开发。由此取得的经验在10年之后应对更大的菲律宾皮纳图博火山喷发中得到了应用。飓风学也以同样的方式从早期的观测结果中获得了进步。     

2004年12月26日苏门答腊—安达曼地震激发的地球自由振荡

根据300~500S的面波估计得到的哈佛大学矩心矩张量断层机制,当周期大于1000S时,地球的地震自由振荡的振幅将异常地大。我们对一个比较陡的断层应用根据地震的体波和面波得到的更真实的破裂模型,估计了自由振荡的振幅近似等于地震矩(6.5×1022N.M),这相当于矩震级为9.15。由于破裂的持续时间达600S,故断层破裂模型足以描述地震的观测结果,但却低估了大地测量位移,这些位移表明在尼科巴群岛和安达曼群岛下面发生了缓慢的断层运动。     

选修模块“海洋地理”的理解与实施

随着世界经济的发展和科技的进步，人类对资源的需求与日俱增，从而海洋——海洋资源的开发利用、海洋环境的保护和管理，以及海洋教育——已受到各国的普遍重视。选修模块“海洋地理”的设置，正是基于人类对海洋关注的日益加强，其目的是要使学生了解有关海洋的基础知识，认识海洋对人类生存与发展的意义，增强海洋意识。     

Sedimentation rates in the Wanggang salt marshes, Jiangsu

1 IntroductionLand-ocean interaction in coastalzone is one of the key m atters of the International G eosphereand Biosphere Program (IG BP). The key problem s of the second phase in the next decadeinclude the m aterial cycle, the system evolution process …     

福建省水氡观测资料变化规律与质量分析

本文对福建省水氡观测资料变化规律进行分析,并试图利用相对均方差、拟合噪声水平和相对年变幅等三项指标,对福建省8个水氡点的观测资料质量进行初步探索。