Climatic difference in dry and wet season under effect of the Longitudinal Range-Gorge and its influence on transboundary river runoff

Based on observed data of transboundary river runoffs in the Longitudinal Range-Gorge Region （LRGR） and those of precipitation and air temperature fields in Yunnan, climatic variability in dry and wet seasons under the impact of LRGR and its influence on transboundary river runoff are studied by means of statistical analysis and wavelet transforms. Results show that latitude variations of high correlation center for precipitation field and corresponding transboundary river runoff are not so notable due to the underlying topography of LRGR, while longitude variations are highly marked. In dry season, greater precipitation and slighter relative deviation are observed in the eastern part as compared to those in the western part of LRGR; while lower average temperature and greater standard deviation are found in the eastern part. In wet season, greater precipitation and slighter relative deviation are ob- served in the western part, while lower average temperature and similar standard deviation are found in the eastern part. Either in dry or wet season, relative deviation of eastern runoff is always greater than that of the western one. LRGR＇s barrier action is stronger for southwest monsoon but weaker for northeast one. Under the effect of LRGR, precipitation variations in the eastern and western parts are primarily found in smaller timescales, and the variations tend to be insignificant as timescales increase; whereas slighter temperature variations are observed In recent years, precipitation in wet season tended to increase, which in turn resulted in the greater runoff of transboundary rivers. While in the past decade, air temperature showed a climbing trend in both dry and wet season in the LRGR.     

水文学原理与测验教学方法的研究与应用

研究了我校水文学与水资源专业水文学原理与测验教学的现状以及面临的问题。在此基础上,研究了水文气象实验教学方法及其在教学中应用的情况进行了探讨。     

地矿类高校水文学原理教学与实践探讨

本文阐述了目前地矿类高校水文学原理教学所遇到的问题,提出针对地矿类高校的水文学原理教学改革设想,并结合教学体会,探讨探讨该课程的教学方式。了水文地质学基础的研究型教育的方法。     

龙脉水库除险加固设计洪水分析研究

采用实测暴雨资料进行设计洪水复核,为龙脉水库除险方案和加固措施提供依据.复核中,通过对暴雨特性、暴雨频率分析,以设计点暴雨、设计雨型和设计面暴雨,采用扣损法进行产流复核分析,并进行时程分配,利用瞬时单位线法进行汇流复核计算,从而确定了水库除险加固设计洪水.通过与推理公式、经验公式和原设计成果比较分析,采用瞬时单位线法的洪水复核成果更为合理.     

Knowledge-based land use/cover classification of remote sensing image in Kenli, Shandong Province, China

Quantitative remote sensing methods have been widely adopted for land use/cover information extraction. However, in the Yellow River delta, spectral confusions between different surface features are common, which always introduce errors into the ordinary automatic spectral classification. A knowledge-based land use/cover classification is tried. Based on a systematic analysis of the spectral characteristics of different land use/cover types in the study area, several index models derived from TM digital data of Kenli County are built, which can make pixels of certain land use/cover types enhanced. With the combination of the index models, the expert knowledge of the area and some ancillary data, such as land use maps and soil maps based on ground surveys, rules of every class are determined to extract the land use/cover information. Accuracy evaluation shows that without any manual modification, the land use/cover information determined with remote sensing is 81.8% and accuracy for the spatial distribution of land use/cover cross checked with a random sample is 84.5%. Therefore, this approach provides an effective means for land use/cover information extraction in the Yellow River delta and can be used as reference for other areas where spectral confusions commonly exist.     

Hydrologic and climatic implications of a multi－disciplinary study of the mid to late Holocene Lake Eastern Juyanze

A mid to late Holocene exposure in a recently desiccated lake basin in western Inner Mongolia was inves-tigated with regard to palaeoenvir onmental changes and theoverall climatic conditions in NW China between 2.7 and 5.4 cal. ka BP. High lake levels of Lake Eastern Juyanze were recorded by ostracod assemblages, shell geochemistry and sedimentology between 5.1 and 4.1 cal. ka BP. Relatively bumid conditions and a relatively strong influence of the Asian monsoon are indicated by palynological data for the corresponding period. Lake levels decreased afterwards and short-term regressive events occurred at about 4.1, 3.8 and 3.4 cal. ka BP. The overall trend towards lower lake levels culminated in repeated episodes of desiccation of Lake East-ern Juyanze between 3.2 and 2.9 cal. ka BP, in phase with very arid conditions inferred from the palynological record.Individual regressive events as well as the rapid environ-mental fluctuations of Lake Eastern Juyanze at about 3.0 cal.ka BP were regarded as driven by mid to late Holocene summer monsoon fluctuations, supported by the Dunde ice core record.     

地貌特征瞬时单位线的原理和应用

本文应用隐含马尔柯夫链的概念,阐明了地貌特征瞬时单位线的基本原理,推导了三、四、五级流域的数学模型.用南方和北方地区六个流域的93次实测洪水资料对模型进行了检验,结果表明,地貌IUH计算的洪峰流量的合格率达到80%以上.本文还建议了对无资料地区推求作为动力特征的特征流速的方法.     

模糊水文学

文中提出创建新学科模糊水文学，水文科学领域内的现象有着两种非确定性：随 机代与模糊性。随机性已为人们所普遍认识，并在实际工作中广泛应用概率统计理论 研究处理水文现象的随机性。但对水文现象的模糊性的研究却不多见。显然，模糊水 文学的主要任务在于根据模糊集有关理论考虑水文学科领域内现象的模糊特性，使 水文学更好地用于实践，促使水文科学进一步发展。     

水文分期描述的模糊统计方法

提出了用模糊统计法以及选配函数法确定汛期模糊集隶属函数的详细方法和步骤。通过实例表明选用升半降半正态分布函数，并依据某些点隶属度的统计计算，可得到与实际情况符合较好的汛期糊模集隶属函数．