Quantitative assessment of drought in a lacustrine wetland based on a water balance model

Upstream inflow decline and excessive water withdrawal are the major reasons for failure in maintaining ecological functions of wetlands and could lead to wetland drought and degradation. Quantitative evaluation of wetlands drought constitutes the basis for managing and scheduling water resources and guaranteeing biological safety. In the study, we proposed a Palmer wetland drought index (PWDI) based on the water balance model that describes wetland hydrological characteristics linked to its located basin to describe drought-reflected ecological characteristics in lacustrine Baiyangdian Wetland and compared it with Palmer drought severity index (PDSI). The results presented that PWDI is able to reflect the worst drought in history, and the drought is mainly affected by water stored in the wetland, but PDSI is inadequate for evaluating the wetland drought. The PWDI methodology provides a clear, objective approach for describing the intensity of drought and can be readily adapted to characterize drought on an operational basis.     

Contamination assessment and health risk of heavy metals in dust from Changqing industrial park of Baoji,NW China

The contents of Co, Cr, Cu, Mn, Ni, Pb and Zn in the dust samples collected from Changqing industrial park of Baoji city, NW China, were measured by XRF, while As and Hg in the dust samples were analyzed by AFS. Geo-accumulation index (I _geo), pollution index (PI) and integrated pollution index (IPI) were calculated to evaluate the heavy metal contamination level of dust. The health risk due to exposure to heavy metals in dust was analyzed by the Health Risk Assessment Model of US EPA. The results show that the arithmetic means of As, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn are 23.3, 16.4, 1591.8, 178.2, 0.243, 346.5, 40.2, 1,586.2 and 1,918.8 mg kg^?1, respectively, which are higher than the background values of Shaanxi soil, especially for Cr, Cu, Hg, Pb, and Zn. The mean values of I _geo reveal the order of Pb > Zn > Cr > Hg > Cu > As > Co > Ni > Mn. The high I _geo of Cr, Cu, Hg, Pb and Zn in dust indicates that there is considerable pollution from Cr, Cu, Hg, Pb and Zn, while the low I _geo of As, Co, Mn and Ni presents no pollution in dust. The assessment results of PI support the results of I _geo, and IPI indicates heavy metals in dust polluted seriously. The health risk assessment shows that ingestion of dust particles is the route for exposure to heavy metals from dust, followed by dermal adsorption. Exposure to As, Cr and Pb from dust may pose a potential health threat to children and adults. The risk of cancer from As, Co, Cr and Ni due to dust exposure is low.     

沉积盆地油气与砂岩型铀矿成矿关系研究

国内外许多砂岩型铀矿产于含油气盆地,油气参与砂岩型铀成矿作用越来越受到人们的重视;沉积盆地控制着油气田和砂岩型铀矿床的分布,多数盆地总体形成内部油气-边部铀矿、下部油气-上部铀矿的分布规律。文章认为油气藏与砂岩铀矿床相互联系的储集层系统及盆地有机/无机成因流体是两者同盆共存的物质基础,吸附作用和还原作用是油气参与砂岩型铀矿成矿的两种主要作用方式,重力流驱动的含铀流体与油气成藏过程中油气扩散形成的烃类流体相互混合是铀成矿作用的主要动力学机制,构造则是两种流体联系的纽带;油气与铀矿相互共生、相互作用,为"以铀找油"和"以油找铀"提供了基础。根据油气与铀的成因联系,结合石油勘探开发资料,提出利用油气田资料"二次开发"寻找砂岩型铀矿的思路和方法。利用油气田资料来寻找砂岩型铀矿,可节约大量勘探资金,提高油气田经济效益,经济价值高。     

基于OMI的亚洲地区对流层NO2高分辨率反演产品POMINO v2.1及其与其他产品的定量对比

对流层二氧化氮(NO₂)是一种重要的痕量污染气体。现有基于OMI卫星探测器、覆盖亚洲地区的NO₂公开产品QA4ECV、OMNO2和POMINO受到广泛使用,然而对于这3个产品的差异的定量认识仍然不足。我们将前期开发的POMINO产品进行了改进和优化,更新至v2.1并将反演区域扩大至覆盖东亚、东南亚和南亚大部分地区,随后定量分析了QA4ECV、OMNO2 v4和POMINO v2.1对流层NO₂垂直柱浓度在2015年—2020年在不同采样条件下的异同。结果显示,POMINO版本的更新对自身NO₂柱浓度反演结果的整体影响较小(<10%)。当3个产品均基于POMINO v2.1进行一致采样时,产品之间在整个亚洲区域的平均差异约为10%,在京津冀等污染地区的差异最高可达40%。3个产品均显示,京津冀地区NO₂柱浓度在五年间下降了约30%,而长三角地区的变化趋势较小。当3个产品进行分别采样时,POMINO v2.1的有效数据量比其他两个产品增加了11%—44%,特别是更好地保留了重...     

青藏高原晴天太阳直接辐射的计算和分析

本文根据1979年5～8月青藏高原气象科学实验资料,研究了利用卡斯特洛夫公式计算青藏高原晴天太阳直接辐射的有关问题。首先从原始资料中挑选出晴天太阳直接辐射并计算其日平均辐照度,然后以此为标准,利用迭代法反求可能太阳直接辐射日平均辐照度理论公式中的系数C,建立该系数与平均水汽压的经验公式,再利用经验式反演晴天太阳直接辐射。本文还比较了由乌克兰英采夫法确定的可能太阳直接辐射与实际晴天太阳直接辐射的差异,证实前者要比后者偏大,其偏离程度随站点拔海高度增加而缩小。文中最后讨论了青藏高原晴天太阳直接辐射日平均辐照度的地理分布,并分析了其随拔海高度的变化。     

CHARACTERISTIC DISTRIBUTION OF SLOPE SCATTERED RADIATION WITH ITS CALCULATION MODEL*

Detailed analysis is made of anisotropy of slope scattered radiation (SSR) in terms of the data obtained by a pyranometer mounted on a theodolite,indicating the change of SSR as a function of orientation and slope.And also reviewed are the models for SSR calculation developed by earlier researchers through the tests with the data.On this basis a new model for SSR flux density is proposed which is of higher applicability and has advantage over the analogues abroad both in physical implication and accuracy of the calculations.     

层次空间推理机制及其在路径寻找方面的应用

Human beings use hierarchies to simplify their conceptual models of reality and to perform reasoning more efficiently. Hierarchical structures are conceptually imposed on space and allow performance of complex tasks in very large contexts easily. Hierarchical spatial reasoning is an important method for solving spatial problems. This paper briefly discusses the definition and frame of hierarchical spatial reasoning and its application to way-finding of road networks.     

电子地图的信息组织及可视化机制

Based on research on information organization and visualization mechanism of multimedia electronic map, this paper proposes an organization method about spatial information and multimedia information of multimedia electronic map： seamless spatial data were organized and managed by stratified expansion R-tree and Quad-tree hierarchy; and multimedia information data were organized and managed by hypermedia model based on an electronic map. Considering electronic map features, the paper also proposes a method for spatial date organization, which integrates Digital Landscape Model and Digital Cartographic Model, and a hybrid model between vector and raster spatial data. Then, the paper studies information visualization mechanism of multimedia electronic map. Finally, the paper certifies the results via a case of multimedia electronic map authoring tools software-Atlas2005.     

中国大气净辐射的气候特征

根据ＥＲＢＥ和ＩＳＣＣＰ资料以及实测和计算和地表净辐射资料进行了计算，并讨论了我国大气净辐射的气候特征；分析了其与各辐射分量及影响因子的关系。结果表明，大气净辐射与大气吸收波辐射有很高的线性关系，并可由此建立起统一的大气净辐射计算式。