The relationship between ENSO cycle and high and low-flow in the upper Yellow River

Firstly, the hydrological and meteorological features of the upper reaches of the Yellow River above Tangnag are analyzed based on observation data, and effects of EI Nino and La Nina events on the high and low flow in the upper Yellow River are discussed. The results show El Nino and La Nina events possess consanguineous relationship with runoff in the upper Yellow River. As a whole, the probability of low flow occurrence in the upper Yellow River is relatively great along with the occurrence of El Nino event. Moreover, the flood in the upper Yellow River occurs frequently with the occurrence of La Nina event. Besides, the results also show dissimilarity of El Nino event occurring time exerts greater impact on high flow and low flow in the upper Yellow River, that is, the probability of drought will be greater in the same year if El Nino event occurs in spring, the high-flow may happen in this year if El Nino occurs in summer or autumn; the longer the continuous period of El Nino is, the lower the runoff in the upper Yellow River is.     

弱震条带对2001年首都圈地区中等地震活动的指示意义

比较系统分析总结了2001年首都圈及邻近地区中等地震发生前小震活动特征及所形成的弱震条带，6次中等地震前均出现了弱震活动有序分布现象，由2～3级地震组成的弱震条带后发生中等地震的可能性更大，但条带长度和持续时间与地震震级关系不甚明显，这些规律特点可为日常短临跟踪及分析预报提供借鉴资料。     

华北平原第四系下限的再研究

华北平原各省市第四系下限、内分层时限皆不相同，使相关研究缺乏统一的语言。依照《中国地层指南》的规定，据现有材料对华北平原第四系划分进行了再研究，明确河北平原原定早更新世固安组后于上新统，由于石油系统同样执行《中国地层指南》的原则，则固安组是明化镇组的同义名，应废弃。现有工作显示华北平原N／Q界线没有超过500m。     

Characteristics of fault rocks and paleo-earthquake source along the Koktokay-Ertai fault zone,Xinjiang,China

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西太平洋海-气相互作用研究进展

主要对近十几年来我国在西太平洋海域海-气相互作用方面的研究成果作一简要回顾通过参与国际合作，我国在西太平洋海域已经获得大量观测资料，并在海气能量交换和物质交换方面取得了不少科研成果这些成果主要包括：（1）近中国海和热带西太平洋海域的海面动量、热量交换特征；（2）西太平洋及暖油海域的边界层特征；（3）海上气溶胶特性及分布规律；（4）热带西太平洋海-气二氧化碳交换。     

模拟酸雨对水稻叶片反射光谱特性影响的初步研究

本文研究了模拟酸雨对水稻叶片反射光谱特性的影响。结果表明：模拟酸雨会引起水稻叶片反射光谱的可见光区和中红外区的反射率升高，近红外区的反射率降低，相应的反射率比值也随之变化，一阶和二阶微分光谱蓝移，且上述变化的程度与酸雨的酸度、水稻的品种和生育期有关。这一结果也表明遥感技术监测酸雨污染作物是可行的。     

QβstructureofthecrustanduppermantleintheeasternSino┐Koreanparaplatform

ＱβｓｔｒｕｃｔｕｒｅｏｆｔｈｅｃｒｕｓｔａｎｄｕｐｐｅｒｍａｎｔｌｅｉｎｔｈｅｅａｓｔｅｒｎＳｉｎｏ┐ＫｏｒｅａｎｐａｒａｐｌａｔｆｏｒｍＺＨＥＮＧ－ＱＩＮＨＥ（何正勤），ＴＡＩ－ＬＡＮＹＥ（叶太兰）ａｎｄＷＥＩ－ＧＵＯＳＵＮ（孙为国）Ｉｎｓｔｉ...     

一种视点相关球面地形LOD算法

在地形可视化领域,基于海量数据的全球地形3维可视化已经得到广泛关注和研究。在经典ROAM算法的基础上,提出了一种视点相关全球地形LOD模型SROAM。该算法采用正方体作为网格细分的顶层,正方体上每一个面分裂成两个三角形作为ROAM算法二又树的根节点。给出了高程数据球面映射的方法,在动态误差计算过程中,考虑了地平线约束条件,进一步对网格进行简化。实验结果表明,此算法能实时动态地生成全球地形LOD模型,实现全球地形场景的平滑绘制。     

Impact of Land Use Changes on Habitat Quality in Altay Region

Altay region is located in the northern part of Xinjiang, and has complex and diverse internal geomorphic types, undulating terrain and a fragile ecosystem. Studying the impact of land use changes on habitat quality is of great significance to regional ecological protection and development, rational planning and utilization, and ensuring the sustainable development of the ecological environment. Based on the InVEST model, combined with land use panel data and topographic relief data of the Altay region, this paper studied the habitat quality from 1995 to 2018. The results show that cultivated land, water area and construction land increased gradually from 1995 to 2018, while grassland and unused land decreased. Forestland remained stable in the first five periods, but increased significantly in 2018. During 1995-2018, all land use types were transferred, mainly between cultivated land, forestland, grassland and unused land in the flat and slightly undulating areas. Poor habitat quality was dominant during 1995-2018. Habitat quality decreased significantly in 2015, which was related to the rapid expansion of cultivated and construction land as threat sources, as well as the decrease of forest and grassland as sensitive factors. However, habitat quality improved significantly in 2018, because a large amount of cultivated land and unused land were converted into forest land and grassland with high habitat suitability. Land use type has an important influence on habitat quality. The distribution characteristics of habitat quality for topographic relief types from good to bad were: large undulating area>medium undulating area>small undulating area>flat area>slightly undulating area. The findings of this study are of great significance for coordinating social, economic, and ecological development in this region and in similar areas.     

Spatiotemporal changes of land desertification sensitivity in northwest China from 2000 to 2017

Sensitivity assessment is useful for monitoring land desertification.Research into how to prevent and control desertification is also important.In the arid region of northwest China,desertification is becoming worse and is a serious problem that affects local sustain-able development.Based on remote-sensing and geographic information system technology,this study establishes a"soil-terrain-hydrology-climate-vegetation"desertification sensitivity comprehensive evaluation system to reflect the spatiotemporal changes of land desertifica-tion,and proposes a spatial distance model to calculate a desertification sensitivity index.The spatiotemporal change characteristics of land desertification sensitivity in northwest China are quantitatively assessed from 2000 to 2017.Moreover,the main driving factors are ana-lyzed using the geographical detector method.The results show the following.(1)Terrain,soil,climate,vegetation and hydrology affect and restrict each other,and constitute the back-ground conditions of the distributions and changes of sensitivity to desertification in northwest China.(2)Desertification sensitivity generally displays a low distribution characteristic on the periphery of the area and a high one in the interior.The low-sensitivity regions are mainly in the five major mountain ranges(Altai Mountains,Tianshan Mountains,Kunlun Mountains,Altun Mountains and Qilian Mountains),while the high-sensitivity regions are mainly in re-gions such as the Junggar Basin,the Tarim Basin and the Inner Mongolia Plateau,as well as the Taklimakan Desert,Badain Jaran Desert and Tengger Desert.The spatial distribution of desertification sensitivity is obviously regional,and the high-and low-sensitivity regions have clear boundaries and a concentrated distribution.(3)With regard to spatiotemporal evolution,changes in desertification sensitivity since 2000 have been predominantly stable,and the overall sensitivity has displayed a slowly decreasing trend,indicating that potential desertifi-cation regions are decreasing annually and that some achievements have been made in the control of regional desertification. (4) Soil and climate play a direct role in the driving factors of desertification in northwest China, and these have been found to be the most important in-fluential factors. Vegetation is the most active and basic factor in changing the sensitivity. In addition, topography and hydrology play a role in restricting desertification changes. So-cio-economic factors are the most rapid factors affecting regional desertification sensitivity,and their impacts tend to be gradually increasing. In general, desertification has been effec-tively controlled in northwest China, and positive results have been achieved in such control.However, against the backdrop of intensified global climate change, increasingly prominent human activities and new normals of socio-economic development, the monitoring, assess-ment and control of desertification in China still have a long way to go.