Characteristics of dry-wet abrupt alternation events in the middle and lower reaches of the Yangtze River Basin and the relationship with ENSO

During recent decades, more frequent flood-drought alternations have been seen in China as a result of global climate change and intensive human activities, which have significant implications on water and food security. To better identify the characteristics of flood-drought alternations, we proposed a modified dry-wet abrupt alternation index (DWAAI) and applied the new method in the middle and lower reaches of the Yangtze River Basin (YRB-ML) to analyze the long-term spatio-temporal characteristics of dry-wet abrupt alternation (DWAA) events based on the daily precipitation observations at 75 rainfall stations in summer from 1960 to 2015. We found that the DWAA events have been spreading in the study area with higher frequency and intensity since 1960. In particular, the DWAA events mainly occurred in May and June in the northwest of the YRB-ML, including Hanjiang River Basin, the middle reaches of the YRB, north of Dongting Lake and northwest of Poyang Lake. In addition, we also analyzed the impact of El Niño Southern Oscillation (ENSO) on DWAA events in the YRB-ML. The results showed that around 41.04% of DWAA events occurred during the declining stages of La Niña or within the subsequent 8 months after La Niña, which implies that La Niña events could be predictive signals of DWAA events. Besides, significant negative correlations have been found between the modified DWAAI values of all the rainfall stations and the sea surface temperature anomalies in the Nino3.4 region within the 6 months prior to the DWAA events, particularly for the Poyang Lake watershed and the middle reaches of the YRB. This study has significant implications on the flood and drought control and water resources management in the YRB-ML under the challenge of future climate change.     

中国东部植被NDVI对气温和降水的时空响应(英文)

Temporal and spatial response characteristics of vegetation NDVI to the variation of temperature and precipitation in the whole year,spring,summer and autumn was analyzed from April 1998 to March 2008 based on the SPOT VGT-NDVI data and daily temperature and precipitation data from 205 meteorological stations in eastern China.The results indicate that as a whole,the response of vegetation NDVI to the variation of temperature is more pronounced than that of precipitation in eastern China.Vegetation NDVI maxi...     

塔中Ⅰ号坡折带上奥陶统礁滩的白云石化及其储集意义

塔里木盆地塔中Ⅰ号坡折带上奥陶统良里塔格组礁滩灰岩发生了少量白云石化作用。白云石化主要发育在溶洞充填的钙质渗流粉砂,泥晶生物碎屑灰岩的泥晶基质,亮晶颗粒灰岩的钙藻屑、藻砂屑、藻泥屑等三种组构中。白云石化直接贡献了平均1%的孔隙度,同时产生的白云石晶间孔为进一步溶蚀提供了通道,对有效储层的形成起到了重要作用。高镁方解石生物是白云石化所需镁离子的重要来源。这套与生物白云石化相关的礁滩储层地质预测需要深入研究钙藻、海百合等生物的古生态、岩相环境及分布。     

正态分布检验在地下水检测质量控制中的应用

对地下水调查中37种必测组分检测过程的替代物进行筛选,应用D’Agostino法对替代物的测量结果进行正态性检验。利用正态分布函数"3σ"原则,定义了各替代物质量控制指标的有效区间。应用正态函数随机变量的数学期望和方差,计算得到各替代物有效区间内的正态函数分布概率均大于97%,替代物过程能力指数计算结果表明,二溴氟代甲烷、甲苯-d8、对溴氟苯、1,2-二氯苯-d4、氟苯等挥发性有机污染物分析过程选用的替代物质量控制过程处于稳定的监控状态;2,4,5,6-四氯间二甲苯、二丁基氯菌酸酯、p-三联苯、十氯联苯等半挥发性有机污染物分析过程选用的替代物监控指标分析过程能力不足。建议参考美国EPA方法中有关监控指标质量控制区间的要求,适当放宽对半挥发性有机物检测流程中选用的替代物质量控制区间的有效范围。正态分布在地下水检测过程质量控制中的应用,为实验室检测过程的质量管理提供了科学、有效的数学依据。     

春播期亚欧环流形势的客观分型及其在物理-统计预报中的应用

本文对1972—1978年七年春播期(3月27日—5月10日)500mb亚欧环流形势,应用变K-均值聚类法进行客观分型,共得九型。对它们和春播期四种主要中期天气过程——连阴雨和低温连阴雨、过程性天气、连晴,用对应分析方法数量化。以环流形势与同期的北半球500mb波谱分析中选出的物理量作为因子,对天气过程类型作出了逐步回归和AID聚类的统计推断。 对1979、80年春播期作了预报检验,效果尚好。     

Some Insights into Topographic,Elastic and Self-gravitation Interaction in Modelling Ground Deformation and Gravity Changes in Active Volcanic Areas

Surface displacements and gravity changes due to volcanic sources are influenced by medium properties. We investigate topographic, elastic and self-gravitation interaction in order to outline the major factors that are significant in data modelling. While elastic-gravitational models can provide a suitable approximation to problems of volcanic loading in areas where topographic relief is negligible, for prominent volcanoes the rough topography could affect deformation and gravity changes to a greater extent than self-gravitation. This fact requires the selection, depending on local relief, of a suitable model for use in the interpretation of surface precursors of volcanic activity. We use the three-dimensional Indirect Boundary Element Method to examine the effects of topography on deformation and gravity changes in models of magma chamber inflation/deflation. Topography has a significant effect on predicted surface deformation and gravity changes. Both the magnitude and pattern of the geodetic signals are significantly different compared to half-space solutions. Thus, failure to account for topographic effects in areas of prominent relief can bias the estimate of volcanic source parameters, since the magnitude and pattern of deformation and gravity changes depend on such effects.     

24万年来西昆仑山甜水海湖岩芯碳酸盐含量变化与气候环境演化

青藏高原现代气候与环境存在着明显的区域差异。高原西北部的西昆仑山甜水 海地区是高原上气候最干旱的区域。作者于１９９５年６月在该区海拔４８４０ｍ的湖盆首次打钻取芯（ＴＳ９５孔）,获得５７ｍ湖泊岩芯,经对样品的实验室测年和多项环境指标分析,表明,ＴＳ９５孔岩芯覆盖了距今２４０－１７ｋａ间的时间尺度。期间,经历了倒数第二次冰期,末次间冰期,末次冰期早期,末次冰期间冰阶和末次冰盛期几个气候变化阶段。岩芯中     

中国近海天然气水合物找矿前景

天然气水合物是一种新型能源，在海底沉积物和陆上永远冻土带中均有广泛分布。西太平洋是全球三大天然气水合物成矿带之一，在其中已发现许多水合物矿床或矿点。中国近海，包括南海、东海和台湾东部海域，具备良好的天然气水合物成矿条件和找矿前景，并已在这些海域中发现了一系列的找矿标志。南海的西沙海槽、台湾西南陆坡和台西南盆地、笔架南盆地及其东缘增生楔、东沙群岛东南坡、南部陆坡区，东海的冲绳海槽和台湾东北部海域是中国近海最有利的天然气水合物找矿远景区。     

Absorption properties of urban/suburban aerosols in China

The broadband diffuse radiation method is improved to retrieve the aerosol refractive index imaginary part （AIP） and broadband （400-1000 nm mean） single scattering albedo （SSA）. In this method, four sets of SSA selection criteria are proposed for quality control. The method is used to retrieve AIP, SSA and absorptive optical thickness （AbOT） from routine hourly-exposed pyrheliometer and paranometer measurements over 11 sites （meteorological observatories） in China during 1998-2003. Apart from one suburban site （Ejin Qi）, the other urban sites are all located around big or medium cities. As shown in the retrieval results, annual mean SSA during 1998-2003 changes from 0.941 （Wuhan） to 0.849 （Lanzhou）, and AIP from 0.0054 to 0.0203. The 11-site average annual mean SSA and AIP are 0.898 and 0.0119, respectively. SSA during winter is smaller for most sites. There is an evidently positive correlation between SSA and aerosol optical thickness （AOT） for all sites. There is also a positive correlation between SSA and relative humidity for most sites, but a negative correlation for a few sites, such as Kashi and ǚrǚmqi in Northwest China.     

四川那朗地区多金属矿化地质及激电特征

四川那朗地区地处三江成矿带,区内出露三叠系灰岩、板岩及火山岩,有闪长岩岩株侵入其中,地表见铁帽。岩体蚀变分带明显。通过激发极化法工作,由视极化率处理后异常显示,原始数据圈出了激电异常,推测为铁帽下部之矿（化）致异常。