The Second Modified Perpendicular Drought Index (MPDI1): A Combined Drought Monitoring Method with Soil Moisture and Vegetation Index

Since soil moisture and vegetation index are direct and important indicators for surface drought status, a new drought monitoring method (MPDI1) is developed in NIR-Red reflectance space. It is a combination of two satellite-derived variables—a soil moisture component using the Perpendicular Drought Index (PDI), and a vegetation component using the Perpendicular Vegetation Index (PVI). Enhanced Thematic Mapper Plus (ETM+) image and in-situ ground observation are introduced to validate the accuracy of the proposed method. Results indicate that MPDI1 is highly consistent to the in-situ ground observation with the coefficient of determination (R²?=?0.49) between MPDI1 and 5–20 cm mean soil moisture, which is slightly higher than the coefficient of determination (R²?=?0.42) between MPDI1 and 10 cm soil moisture. Compared with drought indices such as PDI and the Modified Perpendicular Drought Index (MPDI), MPDI1 provides quite similar trends for bare soil or lower vegetated surface, but it demonstrates a better performance in measuring densely vegetated surface. This paper concludes that MPDI1 provides correct and sufficient information on surface drought status in soil-plant continuum, which appears to have robust available and great potential for surface drought estimation in China and other countries.     

Diatom‐based reconstruction of summer sea‐surface salinity in the South China Sea over the last 15 000 years

We present a new reconstruction of summer sea‐surface salinity (SSS) over the past 15 000 years based on a diatom record from piston core 17940, located on the northern slope of the South China Sea (SCS). The reconstructed diatom‐based summer SSS values for the modern period are in accord with instrumental observations of summer SSS in the area. Here, the modern summer SSS is primarily controlled by river runoff, in particular from the Pearl River. The reconstruction presented in this study shows that the summer SSS varied between 33.3 and 34.2 psu over the past 15 000 years. The long‐term summer SSS trend closely followed the trend of the orbitally controlled solar insolation at 20°N, suggesting that orbital forcing was the dominant driver of changes in summer SSS in this area. Comparisons to speleothem δ¹⁸O data and studies of surface hydrography in the region suggest that changes in solar insolation affected the summer SSS through changes in the East Asian Monsoon and sea‐level changes associated with the last deglaciation. Univariate spectral analyses indicate that centennial‐scale oscillatory variations in summer SSS were superimposed on the long‐term trend. During the deglacial period (c. 12 000–9000 cal. a BP), the dominant periodicity was centred around 230–250 years, whereas a ～350‐year oscillation dominated in the period 2200–4500 cal. a BP. The balance of evidence suggests that these centennial‐scale changes in summer SSS may have been driven by solar‐induced changes in the East Asian Monsoon, but further evidence is needed to firmly establish this relationship.     

高层建筑荷载引发地面沉降与隆起变形三维数值模拟

针对地下水埋深较浅地区,由高层建筑荷载引起的土体变形问题,以比奥固结理论为基础,结合土体非线性流变理论,将土体本构关系推广到黏弹塑性;同时考虑土体力学参数及水力参数的动态变化关系,建立了高层建筑荷载引发地面沉降与隆起变形的三维有限元数值模型,详细研究了高层建筑荷载影响下的土体变形特征及此过程中土体力学参数及水力学参数的变化特征。结果表明：由高层建筑荷载引起的地面沉降呈现漏斗状,以建筑物中心为漏斗中心,高层建筑荷载施加初期,高层建筑周围出现隆起,到达最大值后隆起逐渐消失;高层建筑底部浅层土体孔隙度、渗透系数及泊松比均呈现缓慢减小趋势,弹性模量呈现缓慢增大趋势;而高层建筑周围浅层土体的孔隙度、渗透系数及泊松比呈现先增大后减小的变化趋势,弹性模量则呈现先减小后增大的变化趋势;高层建筑影响区域浅部土体参数的变化趋势与土体的回弹及压缩有关。     

中国及邻区印支运动特征及其意义

通过概要论述印支运动在中国及邻区的表现特征,探讨了印支运动的主要成矿作用,指出印支运动首次使长期以来游离于全球主要大陆外的扬子、中朝、塔里木等小陆块拼合在一起,为新生代大型聚煤盆地的形成奠定了基础,也为燕山期和喜马拉雅山期二次大规模的对流地幔输入大陆事件奠定了重要基础,使之成为中国及邻区大陆上最重要的成矿时期。     

Zero-valent iron/persulfate(Fe0/PS) oxidation acetaminophen in water

Zero-valent iron (Fe⁰), as an alternative iron source, was evaluated to activate persulfate (PS) to degrade acetaminophen (APAP), a representative pharmaceutically active compound in water. Effects of key factors in the so-called Fe⁰/PS process, including Fe⁰ dosage, initial pH, temperatures and chelating agents, were studied. Under all the conditions tested, the APAP degradation followed a pseudo-first-order kinetics pattern. The degradation efficiency of APAP was highest when the Fe⁰ to PS molar ratio increased to 1:1, and the degradation rate constant and removal were 23.19 × 10^?3 min^?1 and 93.19 %, respectively. Comparing with Fe²⁺, Fe⁰ served as an alternative iron source that can gradually release Fe²⁺ into water, thereby consistently activating PS to produce sulfate radicals. The Fe⁰/PS system was effective in a broader pH range from 3 to 8.5. Heat could facilitate production of sulfate radicals and enhance the APAP degradation in the Fe⁰/PS system. High reaction temperature also improved the Fe²⁺/PS oxidation of APAP. Finally, sodium citrate (a chelating agent) at an appropriate concentration could improve the APAP degradation rate in the Fe²⁺/PS and Fe⁰/PS system. The optimal molar ratio of Fe⁰ to citrate depended on solution pH. Our results demonstrated that Fe⁰ was an alternative iron source to activate PS to degrade APAP in water.     

苏北榴辉岩的稀土元素地球化学及其成因讨论

江苏北部的榴辉岩出露于东海群变质岩系中，榴辉岩的产状是：１）呈似层状或透镜状产于东海群片麻岩中；２）呈不规则团块状产于超镁铁岩中，或与超镁铁岩伴生。全岩分析表明，前者相当橄榄拉斑玄琥岩或石英拉斑玄武岩，后者相当橄榄玄武岩或橄榄拉斑玄武岩。     

A comparative study of landslide susceptibility mapping using weight of evidence,logistic regression and support vector machine and evaluated by SBAS-InSAR monitoring: Zhouqu to Wudu segment in Bailong River Basin,China

The determining of landslide-prone areas in mountainous terrain is essential for land planning and hazard mitigation. In this paper, a comparative study using three statistical models including weight of evidence model (WoE), logistic regression model (LR) and support vector machine method (SVM) was undertaken in the Zhouqu to Wudu segment in the Bailong River Basin, Southern Gansu, China. Six conditionally independent environmental factors, elevation, slope, aspect, distance from fault, lithology and settlement density, were selected as the explanatory variables that may contribute to landslide occurrence based on principal component analysis (PCA) and Chi-square test. The relation between landslide distributions and these variables was analyzed using the three models and the results then used to calculate the landslide susceptibility (LS). The performance of the models was then evaluated using both the highly accurate deformation signals produced by using the Small Baseline Subset Interferometric Synthetic Aperture Radar technique and Receiver Operating Characteristic (ROC) curve. Results show more deformation points in areas with high and very high LS levels, and also more stable points in areas with low and very low LS levels for the SVM model. In addition, the SVM has larger area under the ROC curve. It indicates that the SVM has better prediction accuracy and classified ability. For the interpretability, the WoE derives the class of factors that most contributed to landsliding in the study area, and the LR reveals that factors including elevation, settlement density and distance from fault played major roles in landslide occurrence and distribution, whereas the SVM cannot provide relative weights for the variables. The outperformed SVM could be employed to determine potential landslide zones in the study area. Outcome of this research would provide preliminary basis for general land planning such as choosing new urban areas and infrastructure construction in the future, as well as for landslide hazard mitigation in Bailong River Basin.     

南岭地区脉状黑钨矿床成矿母岩的石榴子石研究

根据对南岭地区某些脉状黑钨矿床成矿母岩的石榴子石研究,石榴子石分子的组成是:锰铝榴石55.6％,铁铝榴石39.3％,镁铝榴石1.95％,钙铁榴石3.1％。它们属于锰铝-铁铝榴石类质同象的成分系列。它们的红外光谱表明,这些石榴子石是富锰的锰铝榴石,因为它们的L频带值为302—308cm~(-1)。K频带值为340—343cm~(1-)。L频带值随矿物的MnO含量增加而降低。穆斯鲍尔谱表明,它们的化学位移值为1.247—1.269mm/s,四极分裂值为3.54—3.58mm/s,线宽值为0.269—0.349mm/s。MnO含量增加,FeO含量减少,四极分裂值升高。它们是从壳源型花岗岩浆的晚期富锰分异产物中结晶的。石榴子石的形成温度为550—860℃,压力为1—4kb。     

Characteristics and circulation background of extreme precipitation over East China

Natural Hazards - Using the observed daily precipitation data across East China, this paper analyzes spatiotemporal changes of annual and seasonal extreme precipitation indices during...