基于多尺度遥感数据估算地表通量的方法及其验证分析

地表水热通量(显热通量、潜热通量)的遥感估算在全球气候变化、水资源、生态环境等研究领域具有重要的应用价值.MODIS数据的空间分辨率较低(热红外波段星下点为1 km),而地球表面的几何物理属性又具有高度非均匀性,因而在实际应用中面临较严重的尺度问题.探讨了多源卫星数据(中高分辨率Landsat TM与中低分辨率MODIS)相结合佑算像元通量的2种方法,分别利用高分辫率的地表分类及植被指数信息在混合像元内部进行亚像元处理,以提高非均匀地表混合像元的通量估算精度.研究数据来自于2008年黑河流域综合实验获取的遥感数据和辅助数据,验证数据来自于实验期间获取的不同下垫面的地表通量数据,包括涡度相关(EC)数据,以及大孔径闪烁仪(LAS)数据.计算结果表明,2种方法皆可在下垫面不均匀或者地表类型较复杂的情况下得到比较明显的纠正效果,纠正后的通量与观测更加接近.相比之下,利用植被指数分解温度的方法适用性更广,纠正效果更好.在地面验证中,对比分析了EC和LAS数据在TM尺度和MO-DIS尺度通量验证的适用性.LAS数据测量尺度与MODIS卫星像元尺度相匹配,可以直接验证MODIS通量计算结果,EC数据虽然可以直接验证TM计算的通量,但与MODIS数据对比,还需要进行尺度转换,即先用EC验证TM通量,然后将TM通量降尺度,与MODIS进行对比.最后对利用LAS验证通量的不确定性进行了分析,发现图像中LAS测点的几何定位误差以及LAS测量路径中像元的选取都对验证结果有一定影响.     

大孔径闪烁仪和涡动相关仪观测显热通量之间的尺度关系

利用北京昌平小汤山2002年、2004年涡动相关仪和大孔径闪烁仪的观测数据,借助解析足迹模型计算的源区,分析均匀、非均匀下垫面上涡动相关仪和大孔径闪烁仪观测显热通量之间的差异和关系.结果表明:地表的均匀与非均匀性质,直接影响涡动相关仪和大孔径闪烁仪观测的显热通量的差异大小.在分析均匀、非均匀地表上2种仪器源区重叠面积及重叠区域内足迹值大小与观测通量值之间的关系后,构建一个非均匀地表上2台涡动相关仪与1台闪烁仪观测通量之间的尺度关系式.     

平阴县孝直镇关于大村制新型农村社区建设的探索和实践

平阴县孝直镇属偏远的农业大镇,为解决村庄规模偏小、布局分散和＂空心村＂等问题,充分利用国家城乡建设用地增减挂钩政策,以土地综合整治为平台,积极推进大村制建设,合村并点建设新型社区,从根本上改变农村面貌,加速城镇化和城乡一体化进程。     

Permian basaltic rocks in the Tarim basin, NW China: Implications for plume–lithosphere interaction

There are large areas of Permian basaltic rocks in the Tarim basin (PBRT) in northwestern China. Precise Ar–Ar dating of these rocks revealed an eruption age span of 262 to 285 Ma. Most of the PBRT is composed of alkaline basaltic rocks with high TiO₂ (2.43%–4.59%, weight percent), high Fe₂O₃ + FeO (12.63%–17.83%) and P₂O₅ (0.32%–1.38%) contents. Trace elements of these rocks have affinities with oceanic island basalts (OIB), as shown in chondrite normalized rare earth elements (REE) diagrams and primitive mantle normalized incompatible elements diagrams. The rocks show complex Sr–Nd isotopic character based on which they can be subdivided into two distinct groups: group 1 has relatively small initial (t = 280 Ma)⁸⁷Sr/⁸⁶Sr ratio ( 0.7048) and positive εNd(t) (3.42–4.66) values. Group 2 has relatively large initial ⁸⁷Sr/⁸⁶Sr ratio (0.7060–0.7083) and negative εNd(t) (from − 2.79 to − 2.16) values. Lead isotopes are even more complex with variations of (²⁰⁶Pb/²⁰⁴Pb)t, (²⁰⁷Pb/²⁰⁴Pb)t and (²⁰⁸Pb/²⁰⁴Pb)t ranging from 17.9265 to 18.5778, 15.4789 to 15.6067 and 37.2922 to 38.1437, respectively. Moreover, these two groups have different trace elements ratios such as Nb/La, Ba/Nb, Zr/Nb, Nb/Ta and Zr/Hf, implying different magmatic processes. Based on the geochemistry of basaltic rocks and an evaluation of the tectonics, deformation, and the compositions of crust and lithospheric mantle in Tarim, we conclude that these basaltic rocks resulted from plume–lithosphere interaction. Permian mantle plume caused an upwelling of the Tarim lithosphere leading to melting of the asthenospheric mantle by decompression. The magma ascended rapidly to the base of lower crust, where different degrees of assimilation of OIB-like materials and fractionation occurred. Group 1 rocks formed where the upwelling is most pronounced and the assimilation was negligible. In other places, different degrees of assimilation and fractionation account for the geochemical traits of group 2.     

山东省飞机增雨降水区分级预报方法研究

利用1997～2000年春秋季山东主要降水天气系统中尺度客观分析和降水模拟资料，统计分析了与降水密切相关的15个因子，并对因子的稳定性进行检验。用全部入选因子的前5个主成分作为新的预报因子，建立全省25个区域0～6h和0～12h平均降水量的3类判别方程，判别效果较好。以此方法为基础建立的决策系统为增雨作业指挥提供了实用性技术工具。     

金顶集团矿区不良地质体遥感研究

本文采用大比例尺彩红外航空遥感手段，研究了金顶集团石灰岩矿山边坡滑坡，崩塌和人工泥石流沟等不良好地质问题，通过不良地质体的形态特征，色调差异和堆积特点在航片上的不同反映，判释了不良地质体内的类型，分布，形成条件和严重程度，以及判释和分析了地形地貌，地层岩性，地质构造等工程地质条件及其对不良地质体的影响，为矿山的进一步开发，规划和边坡整治，提供了可靠依据。     

Performance of the stereoscopic system of the HEGRA imaging air erenkov telescopes: Monte Carlo simulations and observations

Based on the Monte Carlo simulations we have studied the performance of the HEGRA system of imaging air erenkov telescopes (IACTs) in its present configuration of 4 IACTs as well as in its future final configuration of 5 IACTs. Here we present the results on the basic characteristics of the IACT system which are used in the standard data analysis procedure, i.e., the collection areas, the detection rates, the angular resolution, the energy resolution, and the γ/hadron-separation efficiency. By comparing several key Monte Carlo predictions with experimental results it is possible to check the accuracy of the simulations. The Monte Carlo results concerning hadron-nuclear showers are tested with the recorded cosmic ray events and the results concerning photon-induced showers are tested with a large data sample of γ-rays observed from BL Lac object Mkn 501 during its high flaring activity in 1997. Summarizing the simulations and current observations we give the basic recommendations of using the instrument and the major values of its sensitivity.     

1695年临汾大震的救灾对策

叙述了1695年临汾8级大地震后,清政府和山西地方军政当局采取的一系列救灾措施,包括派遣中央和地方军要员赶赴现场实施救灾;救治伤员、处理遇难者、清理灾害现场;惩治罪犯,安定社会秩序;制订抚恤标准,发布减免租赋、恢复经济的政策措施;严惩救灾不力的地方官员,募集救灾款项等.研究总结了临汾大震的救灾对策,这对加强地震重点监视防御区的综合防御体系,具有重要的现实意义.     

H-adaptivity applied to liquefiable soil in nonlinear analysis of soil–pile interaction

This paper is concerned with application of the h-adaptive finite element method to dynamic analysis of a pile in liquefiable soil considering large deformation. In finite element analysis of pile behavior in liquefiable soil during an earthquake, especially considering large deformation of liquefied ground, error due to discretization in the zone near the pile becomes very large. Our purpose was to refine the approximation of the finite element method. The updated Lagrangian formulation and a cyclic elasto-plastic model based on the kinematic hardening rule were adopted to deal with the nonlinearity of the soil. The mixed finite element and finite difference methods together with the u-p formulation and Biot's two-phase mixture theory were used. To improve the accuracy and increase the efficiency of finite element analysis, an h-adaptive scheme that included a posteriori error estimation and h-version mesh refinement was applied to the analysis. The calculated results of effective stress were smoothed locally by the extrapolation method and smoothed stress was used to calculate the L₂ norm of the effective stress error in the last step of the calculation of each time increment. The mesh was refined by a fission procedure based on the indication of the error estimate As a numerical example, a soil–pile interaction system loaded cyclically was analyzed by our method.