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101.
Kai Liu Dong Zhao Jun-yong Fang Xia Zhang Qing-yun Zhang Xue-ke Li 《Journal of the Indian Society of Remote Sensing》2017,45(5):805-813
Heavy-metal-contaminated soil is a critical environmental issue in suburban regions. This paper focuses on utilizing field spectroscopy to predict the heavy metal contents in soil for two suburban areas in the Jiangning District (JN) and the Baguazhou District (BGZ) in China. The relationship between the surface soil heavy metal contents and spectral features was investigated through statistical modeling. Spectral features of several spectral techniques, including reflectance spectra (RF), the logarithm of reciprocal spectra (LG) and continuum-removal spectra (CR), were employed to establish and calibrate models regarding to Cd, Hg and Pb contents. The optimal bands for each spectral feature were first selected based on the spectra of soil samples with artificially added heavy metals using stepwise multiple linear regressions. With the chosen bands, the average predictive accuracies of the cross-validation, using the coefficient of determination R2, for estimating the heavy metal contents in the two field regions were 0.816, 0.796 and 0.652 for Cd; 0.787, 0.888 and 0.832 for Pb; and 0.906 and 0.867 for Hg based on partial least squares regression. Results show that better prediction accuracies were obtained for Cd and Hg, while the poorest prediction was obtained for Pb. Moreover, the performances of the LG and CR models were better than that of the RF model for Pb and Hg, indicating that LG and CR can provide alternative features in determining heavy metal contents. Overall, it’s concluded that Cd, Hg and Pb contents can be assessed using remote-sensing spectroscopy with reasonable accuracy, especially when combined with library and field-collected spectra. 相似文献
102.
随着我国文物保护意识的加强,关于唐帝陵的保护不再局限于陵体本身。本文依托于地理国(省)情普查试点项目,通过对陵区监测区两期地表覆盖变化进行对比分析,提出"影响地类变化"反映人类活动对于陵区监测区的影响,并针对唐献陵进行统计分析,为今后陵区保护提供了一定的依据。 相似文献
103.
104.
基于多源数据分析的洼里砾岩地下水循环特征 总被引:1,自引:0,他引:1
利用钻孔、地下水位、水质、温度和同位素等多源数据,识别了洼里地区的地质结构、地下水动态、地下水化学、地下水温度和同位素特征,分析了洼里砾岩与奥陶系、第四系含水层的水力联系。洼里砾岩在西部与奥陶系地层直接接触,与奥陶系含水层存在水量交换通道;洼里砾岩与奥陶系和第四系地下水水位具有一致的年际和年内变化特征,水位高值一般出现在1—2月,水位低值出现在5—6月。同时,洼里砾岩、第四系和奥陶系地下水水化学类型均为HCO3-Ca·Mg型,且C-14和S-34同位素值相近,地下水温度变化规律具有区域一致性。结果表明,洼里砾岩岩溶发育,富水性好,与奥陶系和第四系含水层水力联系密切。地下水循环特征表现为:地下水主要接受西部奥陶系地下水补给,自西南向东北方向径流,主要排泄方式为侧向径流和向第四系含水层越流。 相似文献
105.
通过与陕西省文物局合作,以不可移动文物中的古塔为例,利用FLEX技术建立基于B/S架构的Web地理信息系统,能够实现跨平台的文物数据存储和管理,利用自身优势为文物保护工作提供技术支持。 相似文献
106.
石峁遗址作为重要的考古发现具有重大的学术意义,本文利用三维激光扫描技术、无人机航摄技术、GPS技术、数字化测图技术等多种测绘技术对石峁本体及周边环境进行测量,得到了多种测绘成果,是利用多种信息化测绘技术服务于文物保护的成功应用,为以后开展同类大遗址保护项目积累了宝贵经验。 相似文献
107.
采用IGS发布的GIM数据,提出了一种结合滑动时窗法和临近格网点电离层TEC相关性分析法的联合分析方法,研究了震前电离层异常变化与地震的关系。通过分析震区附近5个格网点TEC的异常变化情况,发现震前电离层TEC发生明显异常变化,且格网点之间的TEC序列相关性受地震显著影响;通过分析二维电离层图的TEC异常空间分布,发现震前三天震中附近分别出现6h、12h和6h的异常。最后利用电离层层析的方法,对电离层异常时刻进行了电子密度的反演,进一步分析了电子密度在电离层异常时刻的分布情况。 相似文献
108.
【目的】了解巨砺属牡蛎的系统关系和种类区分。【方法】对我国沿海分布的7种巨砺属牡蛎(香港牡蛎、有明牡蛎、熊本牡蛎、岩牡蛎、艾氏牡蛎、太平洋牡蛎、葡萄牙牡蛎)的线粒体DNA片段(COI、12S、16S和tRNAs),以及核糖体RNA基因转录间隔子序列(ITS-1、ITS-2和ITS)进行分子系统学研究。【结果】无论种间或种内,tRNAs序列差异最大,亚种内TS1序列差异最大;tRNAs和COI序列较其它序列变异更快,种间变异与种内变异之间有明显的条形码间隙;12S、16S、ITS和ITS2的种间变异与种内变异无重叠及条形码间隙;ITS1的种间变异与种内变异出现重叠。在亚种层面,12S、ITS、ITS1和ITS2的亚种间变异与亚种内变异出现重叠;16S的亚种间变异与亚种内变异无重叠及条形码间隙;tRNAs与COI序列亚种间变异与亚种内变异之间有明显的条形码间隙,有利于区分亚种。【结论】tRNAs和COI序列可用于种及亚种的鉴定。 相似文献
109.
110.
Summer Asian-Pacific Oscillation and Its Relationship with Atmospheric Circulation and Monsoon Rainfall 总被引:1,自引:0,他引:1 下载免费PDF全文
ZHAO Ping CHEN Junming XIAO Dong NAN Sulan ZOU Yan ZHOU Botao 《Acta Meteorologica Sinica》2008,22(4):455-471
Using the ERA-40 data and numerical simulations, this study investigated the teleconnection over the extratropical Asian-Pacific region and its relationship with the Asian monsoon rainfall and the climatological characteristics of tropical cyclones over the western North Pacific, and analyzed impacts of the Tibetan Plateau (TP) heating and Pacific sea surface temperature (SST) on the teleconnection. The Asian-Pacific oscillation (APO) is defined as a zonal seesaw of the tropospheric temperature in the midlatitudes of the Asian-Pacific region. When the troposphere is cooling in the midlatitudes of the Asian continent, it is warming in the midlatitudes of the central and eastern North Pacific; and vice versa. The APO also appears in the stratosphere, but with a reversed phase. Used as an index of the thermal contrast between Asia and the North Pacific, it provides a new way to explore interactions between the Asian and Pacific atmospheric circulations. The APO index exhibits the interannual and interdecadal variability. It shows a downward trend during 1958-2001, indicating a weakening of the thermal contrast, and shows a 5.5-yr oscillation period. The formation of the APO is associated with the zonal vertical circulation caused by a difference in the solar radiative heating between the Asian continent and the North Pacific. The numerical simulations further reveal that the summer TP heating enhances the local tropospheric temperature and upward motion, and then strengthens downward motion and decreases the tropospheric temperature over the central and eastern North Pacific. This leads to the formation of the APO. The Pacific decadal oscillation and El Nino/La Nina over the tropical eastern Pacific do not exert strong influences on the APO. When there is an anomaly in the summer APO, the South Asian high, the westerly jet over Eurasia, the tropical easterly jet over South Asia, and the subtropical high over the North Pacific change significantly, with anomalous Asian monsoon rainfall and tropical cyclon 相似文献