日本古代中心日食记录在地球自转研究中的可能作用

本文介绍了利用古代中心日食记录研究地球自转速率变化的原理以及日本古代的中心日食记载，认为日本中心日食记录的年代虽然不太古老，但能为地球自转变化研究提供有价值的信息。     

由日本古代中心日食记载得到的地球自转速率变化

简要介绍了古代中心日食的观测记载在地球自转变化研究中的意义．给出了由日本的6例古代中心日食记载得到的表示地球自转变化的△T值，相应的日长变化的均值约为1．6ms／cy（cy为世纪，下同）     

由日本古代中心日食记载得到的地球自转速率变化

简要介绍了古代中心日食的观测记载在地球自转变化研究中的意义．给出了由日本的6例古代中心日食记载得到的表示地球自转变化的△T值，相应的日长变化的均值约为1．6ms／cy（cy为世纪，下同）     

由公元1361年一次日全食的记载得到的高精度ΔT值

本文在历书时系统下计算了发生在公元 136 1年 5月 5日的日全食的参数 ,分析了中国古代两地 ,即浙江的松江和天台对这次日全食观测到近中心日食食相的详细记载 ,并依计算结果和对记载的分析 ,采用移动中心食带的方法确定Δλ ,得到表示地球自转变化的高精度ΔT值为 4 80s± 6 0s .     

中国古代中心日食记载与地球自转速率的变化

利用中国古代中心日食（全、环食）的观测记载研究近2千余年间地球自转速率长期变化的原理和方法,讨论了中国古代中心日食和近中心日食观测的记载资料,并利用其中可靠的记载和-26.0″/（100a）²的月球本征加速度值计算得到了表示地球自转长期变化的△T值系列,由此得到表示地球自转长期减慢的日长变化均值约为1.4ms/100a,该平均值相应的历元为A.D.1141。     

由一次西周日食记载得到的地球自转变化

本文结合１９９７年３月９日全食的新疆观测及地球自转变化趋势讨论了发生在中国西周时期的一次日食的记载，以及由此得到的地球自转速度变化值。     

由古代天象记载研究揭示的地球自转变化的两个重要现象

本文简要介绍了利用古代天象观测记载研究地球自转长期变化所揭示的两个重要现象，即存在着使自转速率加速的非潮汐因素；地球自转在约千余年之前出现过较大的起伏。     

由古代天气记载研究揭示的地球自转变化的两个重要现象

本文简要介绍了利用古代天象观测记载研究地球自转长期变化所揭示的两个重要现象，即存在着使自转速率加速的非潮汐因素；地球自转在约千余年之前出现过在的起伏。     

天再旦与日食

《汲冢纪年》有“懿王元年天再旦于郑”的记载。今日学者大多认为是日食。果真如此,对研究地球自转的长期变化会有重要作用。本文考查了在懿王可能所处的９６６～８９５ＢＣ,７２年中,有可能引起“天再旦”的日食,并从纪时日食的角度对地球自转不均匀引起的世界时改正数ΔＴ数值作了分析和讨论。     

古代日月食观测记载和地球自转变化研究

本文简要概述了利用古代日月食观测记载研究地球自转速率变化的意义，原理和方法，以及研究的历史，现状和今后的发展。     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Earthquake Engineering and Engineering Vibration Aims And Scope

正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and     

Foreword

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States.     

WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH(WASER)

正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study     

Enhancing remote sensing research on global change to improve our understanding on Earth system processes

正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases