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941.
Heshan Lin Hongjun Li Xiaolong Yang Zizhou Xu Yindong Tong Xingguang Yu 《中国海洋大学学报(英文版)》2020,19(4):843-852
With the rapid development of industrialization and urbanization of coastal regions, eutrophication and metal pollution have caused serious environmental p 相似文献
942.
This paper tests the idea of substituting the atmospheric observations with atmospheric reanalysis when setting up a coupled data assimilation system.The paper focuses on the quantification of the effects on the oceanic analysis resulted from this substitution and designs four different assimilation schemes for such a substitution.A coupled Lorenz96 system is constructed and an ensemble Kalman filter is adopted.The atmospheric reanalysis and oceanic observations are assimilated into the system and the analysis quality is compared to a benchmark experiment where both atmospheric and oceanic observations are assimilated.Four schemes are designed for assimilating the reanalysis and they differ in the generation of the perturbed observation ensemble and the representation of the error covariance matrix.The results show that when the reanalysis is assimilated directly as independent observations,the root-mean-square error increase of oceanic analysis relative to the benchmark is less than 16%in the perfect model framework;in the biased model case,the increase is less than 22%.This result is robust with sufficient ensemble size and reasonable atmospheric observation quality(e.g.,frequency,noisiness,and density).If the observation is overly noisy,infrequent,sparse,or the ensemble size is insufficiently small,the analysis deterioration caused by the substitution is less severe since the analysis quality of the benchmark also deteriorates significantly due to worse observations and undersampling.The results from different assimilation schemes highlight the importance of two factors:accurate representation of the error covariance of the reanalysis and the temporal coherence along each ensemble member,which are crucial for the analysis quality of the substitution experiment. 相似文献
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采用辉钼矿Re-Os同位素定年,获得的内蒙古阿巴嘎旗比鲁甘干钼矿的辉钼矿Re-Os同位素模式年龄变化范围为236.9±3.7~238.7±2.4Ma,年龄加权平均值为237.9±1.7Ma,表明该矿床形成时代应为印支期。辉钼矿的Re含量平均值为74.065×10~(-6),表明其主要为幔壳混合来源特征。该矿床位于贺根山断裂带以南的兴蒙造山系索伦山-霍林郭勒弧盆系内,为斑岩型钼矿床。钼矿体主要赋存在黑云母花岗斑岩和角岩内,受内外接触带控制。接触带控矿容矿断裂主要有北西向、北东向及近东西向,其内多充填有石英脉。细脉状、网脉状石英脉越发育,钼矿化越强。区域研究表明,印支期是兴蒙造山带及其邻区钼(钨)成矿的重要成矿期之一,但在本区尚属首次发现,为开展索伦山-霍林郭勒成矿带区域成矿规律研究提供了重要参考。 相似文献
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Power law correlation properties of sign and magnitude series have been studied based on the series of observation records of flow of the River Yangtze. The results obtained give improved insight into and understanding of the linear and non‐linear processes of the water cycle. With the newly developed Delayed Vector Variance method and the surrogate test, the documented linkage between the sign series and the linear process, and that between the magnitude series and non‐linear process can be verified. The spectra estimated by detrended fluctuation analysis method show different properties of intra‐annual and inter‐annual correlations in both sign and magnitude series. The linear process behaves as an 1/f noise at a time scale less than about 60 days, but shows features of anti‐persistence in terms of long‐term fluctuation. The magnitudes are clustered in three ways mainly caused by non‐linear processes, i.e. periodic clustering, strong short‐term clustering of 1/f noise at time scales less than 20 days, and long‐term clustering with weak persistence. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
950.
大地电磁法三维共轭梯度反演研究 总被引:12,自引:4,他引:8
Based on the analysis of the conjugate gradient algorithm, we implement a threedimensional (3D) conjugate gradient inversion algorithm with magnetotelluric impedance data. During the inversion process, the 3D conjugate gradient inversion algorithm doesn' t need to compute and store the Jacobian matrix but directly updates the model from the computation of the Jacobian matrix. Requiring only one forward and four pseudo-forward modeling applications per frequency to produce the model update at each iteration, this algorithm efficiently reduces the computation of the inversion. From a trial inversion with synthetic magnetotelluric data, the validity and stability of the 3D conjugate gradient inversion algorithm is verified. 相似文献