八卦庙大型金矿床稀土元素地球化学研究

八卦庙大型金矿床是秦岭造山带中的一种与碳酸盐岩有关的中温热液矿床。本系统总结了该矿床的稀土元素地球化学特征，对矿石、围岩、含金石英脉、酸性岩脉、铁的硫化物中的稀土元素组成、关系及成因进行了分析研究，论证了这个金矿床的形成与围岩、酸性岩脉、地壳深部金的矿源层有关。在此基础上应用简化了的Ｇｒｅｓｅｎｓ方程－Ｇｒａｎｔ方法讨论了热液蚀变过程中稀土元素地球化学行为，并分析了样品中出现Ｃｅ和Ｅｕ异常的原因，     

利用树木年轮重建阿勒泰地区1794-2012年降水量

利用阿勒泰地区3个采样点的西伯利亚云杉（Picea obovata）树轮样本,建立了区域树轮宽度标准化年表。单相关普查发现,阿勒泰地区区域树轮宽度标准化年表与该区域5个气象站上年7月至当年6月降水量相关显著（R=0.714,P<0.00001）。用区域树轮宽度标准化年表可较好地重建该区域上年7月至当年6月的降水量,解释方差达51.0%,验证表明降水重建序列是可信的。重建序列经历了4个偏湿期和4个偏干期。存在2.2～2.5 a的显著周期（P<0.05）及146、2.8、2.1、2.0 a的较显著周期。在1889年发生从少到多的突变。空间相关分析表明重建结果对阿勒泰地区降水具有较好的代表性。重建结果与阿尔泰山、天山中部地区、吉尔吉斯斯坦东部天山北坡的降水变化趋势和干湿阶段具有较好的一致性,与PDSI变化趋势也有较好的一致性。     

Ionospheric and receiver DCB-constrained multi-GNSS single-frequency PPP integrated with MEMS inertial measurements

Single-frequency precise point positioning (SF-PPP) is a potential precise positioning technique due to the advantages of the high accuracy in positioning after convergence and the low cost in operation. However, there are still challenges limiting its applications at present, such as the long convergence time, the low reliability, and the poor satellite availability and continuity in kinematic applications. In recent years, the achievements in the dual-frequency PPP have confirmed that its performance can be significantly enhanced by employing the slant ionospheric delay and receiver differential code bias (DCB) constraint model, and the multi-constellation Global Navigation Satellite Systems (GNSS) data. Accordingly, we introduce the slant ionospheric delay and receiver DCB constraint model, and the multi-GNSS data in SF-PPP modular together. In order to further overcome the drawbacks of SF-PPP in terms of reliability, continuity, and accuracy in the signal easily blocking environments, the inertial measurements are also adopted in this paper. Finally, we form a new approach to tightly integrate the multi-GNSS single-frequency observations and inertial measurements together to ameliorate the performance of the ionospheric delay and receiver DCB-constrained SF-PPP. In such model, the inter-system bias between each two GNSS systems, the inter-frequency bias between each two GLONASS frequencies, the hardware errors of the inertial sensors, the slant ionospheric delays of each user-satellite pair, and the receiver DCB are estimated together with other parameters in a unique Kalman filter. To demonstrate its performance, the multi-GNSS and low-cost inertial data from a land-borne experiment are analyzed. The results indicate that visible positioning improvements in terms of accuracy, continuity, and reliability can be achieved in both open-sky and complex conditions while using the proposed model in this study compared to the conventional GPS SF-PPP.     

自由网平差的经典方法及扩展应用

采用经典的最小二乘参数平差结果为一个特解,进而以坐标系定位参数为参数求出自由网的最小范数解。之后,以若干工程实例列举了除变形监测网以外的扩展应用。     

Analysis of the ore-controlling role of Guojiadian mantle branch structure, Northwest Shandong Peninsula, China

Metallogenesis in the gold ore-concentrated zone of Northwest Shandong Peninsula is closely related to deep processes.The region in the eastern part of North China entered into the stage of mantle plume evolution during the Yanshanian movement,following the long-time stage of stable platform evolution during Paleozoic time.At that time,the ore-concentrated zone of Northwest Shandong Peninsula just entered into the development-evolution stage of the Laiyang sub-mantle plume and the Guojiadian mantle branch structure in its periphery.The core-mantle-source gold was present in the gas-liquid form,and it migrated through mantle plume→sub-mantle plume→mantle branch structure→favorable tectonic expansion zone to the favorable loci of the mantle branch structure,where gold was deposited as ores,thereafter constituting a series of large-to medium-sized gold deposits distributed around the Guojiadian mantle branch structure.This study also dealt with the Jiaojia fault as the main detachment(fault altered rock) belt on the northwestern margin of the mantle branch structure and also presented a basic cognition about the fact that the Sanshandao fault as the listric fault on the hanging wall of the detachment belt.Furthermore,on this basis,this study also pointed out the orientation for further ore prospecting in this region.     

Inversion of Vegetation Components Based on the Spectral Mixture Analysis Using Hyperion Data

Hyper spectral remote sensing is widely used to identify ground objects as a result of the advantages of ground radiation intensity characteristics and spectral position characteristics, in which inversion of vegetation components is the difficult point and hotspot. In this study, Huma county of Heilongjiang Province was selected as the study area, the canopy spectra of four types of typical vegetation were measured in situ firstly, including mongolian oak, cotton grass, lespedeza and white birch. Then, on the basis of analyzing the canopy spectral characteristics and their parameterization, the spectral differences of different vegetations were located, and the parameterization method of characteristics identification was determined. Finally, Hyperion data were used to calculate the canopy albedos based on the bidirectional reflectance model of vegetation canopies, and to map the vegetation components in the study area by use of linear spectral mixture model. The results showed that inversion of vegetation components in high vegetation-covered area was accurate using the canopy albedos and liner spectral mixture model, and was identical with the field sampling, which validated the feasibility of canopy albedos and liner spectral mixture model for the inversion of vegetation components.     

Weak GPS signal tracking using FFT discriminator in open loop receiver

An open loop tracking architecture, which tracks GPS signals under weak and challenging conditions, is analyzed. The in-phase and quadrature-phase integration pair is regarded as a single tone complex signal. An FFT-based method is used as a frequency discriminator to estimate the Doppler frequency residual of the single tone signal. Another FFT-based method applies complex squaring to eliminate the effect of the navigation data bits polarities. The performance of the FFT-based discriminators is assessed in three criteria. Those criteria are the signal strength and dynamic range that can be tracked and the accuracy of the estimated Doppler frequency. In addition, the performance of the discriminators is analyzed to provide the theoretical and simulated peak detection probability. The results indicate that the FFT discriminator can track signals about 5 dB weaker than the signals that can be tracked by the complex squared FFT discriminator. In a quasi-static environment, the Doppler frequency residual can be assumed to be around zero, which can enable the FFT-based discriminators to track signals with approximately 2 dB less power. Moreover, the performance of the FFT-based discriminators is compared with the performance of two other frequency discriminators, namely the fast–slow and power-based. The comparison results indicate that these two frequency discriminators give higher frequency estimation accuracy, but they have a narrower dynamic range.     

对建立遥感估产模式的几点初步认识

本文从分析遥感光谱参数的生物学意义着手，论证了正确建立遥感估产模型的可能途径。对几种有代表性的遥感估产模型作了分析，作者认为把可见光、近红外波段的遥感信息与热红外信息有机结合是解决遥感估产模型的最佳方案。对ＮＯＡＡ－ＡＶＨＲＲ的第１通道与第２通道光谱数值进行非朗伯体特性的纠正是必要的。遥感估产模型不仅可以使估产的空间尺度大大缩小而且参数数目亦可大大减小，更有利于实际运行。     

Correlation analysis between drought indices and terrestrial water storage from 2002 to 2015 in China

Drought monitoring is a key topic in environmental monitoring and assessment although there is still a need to determine the correlation between drought monitoring indices and remote sensing products. We analyzed the correlation between the self-calibrating Palmer Drought Severity Index (sc_PDSI), the Standardized Precipitation Index and the Standardized Precipitation Evapotranspiration Index (SPEI) and terrestrial water storage monitored through the Gravity Recovery and Climate Experiment (GRACE) on a monthly timescale from 2002 to 2015 in China. As a consequence of anomalies in the soil water budget, the highly significant correlation between the sc_PDSI and the GRACE satellite-observed terrestrial water storage suggested that these two datasets are the most suitable for use in monitoring droughts. In comparing the three drought indices, the sc_PDSI was introduced as a means of drought monitoring in the Yangtze, Pearl, Huaihe, Southeast and Songhua River Basins, whereas the SPEI was found to be more applicable to other major river basins, such as the Inland River Basin. These diverse spatial behaviors are caused by the differences between the hydrological droughts characterized by these three drought indices.