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1,240 results on '"SHI Peijun"'

209. Geographically and Ontologically Oriented Scoping of a Dry Valley and Its Spatial Characteristics Analysis: The Case of the Three Parallel Rivers Region.

Author

Zhang, Linhao, Tang, Haiping, Shi, Peijun, Jia, Wei, and Dai, Luwei

Subjects
VALLEYS, LAND cover, GEOGRAPHIC information systems
Abstract

A dry valley is a special landscape type that is formed by the combined effect of climate and topography. Accurately defining the scope of a dry valley and knowledge of its spatial distribution characteristics can provide data support for relevant studies in the region. Starting from natural ontological characteristics and formation mechanisms, we constructed a geographical ontological model of dry valleys through an analysis of concepts related to the dry valley and combined GIS technology and methods to accurately define the scope and analyze the spatial characteristics of the dry valleys in the Three Parallel Rivers Region (DVT). Our results show that: (1) The geographically and ontologically oriented method developed to define the scope of the dry valley has a high accuracy, with an overall accuracy of 92.3% and a kappa coefficient of 0.84, therefore it can provide a better mechanism for defining the scope of a dry valley on a large scale. (2) The total area and total length of the DVT are 6147.1 km2 and 2125.3 km, respectively. The dry valleys in this region are mainly located in the Tibet Autonomous Region and in the Sichuan and Yunnan provinces in China. (3) The terrain in the DVT is precipitous, and areas with slopes greater than 25° account for 70% of the total area of the dry valleys. The DVT area of sunny aspects (north, northeast, and northwest aspects) is larger than that of shady aspects (south, southeast, and southwest aspects), and the land cover is mainly grassland with a desert substrate. The result of our study can provide data support for further in-depth research in related fields of dry valleys. [ABSTRACT FROM AUTHOR]

Published
2023
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218. A New Method for Linear Ill-Posed Problems: Iteration Method by Rectifying Eigenvalue

Author

Tian, Yugang, Shi, Peijun, Wang, Xinzhou, Qin, Kun, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Carbonell, Jaime G., editor, Siekmann, Jörg, editor, Li, Xue, editor, Wang, Shuliang, editor, and Dong, Zhao Yang, editor

Published
2005
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219. Analysis of Spatial and Temporal Variations of the Near-Surface Wind Regime and Their Influencing Factors in the Badain Jaran Desert, China

Author

Hu, Ziying, primary, Wang, Guangpeng, additional, Liu, Yong, additional, Shi, Peijun, additional, Zhang, Guoming, additional, Liu, Jifu, additional, Gu, Yu, additional, Huang, Xichen, additional, Zhang, Qingyan, additional, Han, Xu, additional, Wang, Xueling, additional, Du, Jiewen, additional, Li, Ruoxin, additional, and Liu, Lianyou, additional

Published
2022
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225. Measuring Compound Soil Erosion by Wind and Water in the Eastern Agro–Pastoral Ecotone of Northern China

Author

Lin, Degen, Shi, Peijun, Meadows, Michael, Yang, Huiming, Wang, Jing’ai, Zhang, Gangfeng, Hu, Zhenhua, Department of Environmental and Geographical Science, and Faculty of Science

Abstract

Land degradation induced by soil erosion is widespread in semiarid regions globally and is common in the agro–pastoral ecotone of northern China. Most researchers identify soil erosion by wind and water as independent processes, and there is a lack of research regarding the relative contributions of wind and water erosion and the interactions between them in what is referred to here as compound soil erosion (CSE). CSE may occur in situations where wind more effectively erodes a surface already subject to water erosion, where rainfall impacts a surface previously exposed by wind erosion, or where material already deposited by wind is subject to water erosion. In this paper, we use the Chinese Soil Loss Equation (CSLE) and the Revised Wind Erosion Equation (RWEQ) to calculate the rate of soil erosion and map the distribution of three types of soil erosion classified as (i) wind (wind-erod), (ii) water (water-erod), and (iii) CSE (CSE-erod) for the study area that spans more than 400,000 km2 of sand- and loess-covered northern China. According to minimum threshold values for mild erosion, we identify water-erod, wind-erod, and CSE-erod land as occurring across 41.41%, 13.39%, and 27.69% of the total area, while mean soil erosion rates for water-erod, wind-erod, and CSE-erod land were calculated as 6877.65 t km−2 yr−1, 1481.47 t km−2 yr−1, and 5989.49 t km−2 yr−1, respectively. Land subject to CSE-erod is predominantly distributed around the margins of those areas that experience wind erosion and water erosion independently. The CSLE and RWEQ do not facilitate a direct assessment of the interactions between wind and water erosion, so we use these equations here only to derive estimates of the relative contributions of wind erosion and water erosion to total soil erosion and the actual mechanisms controlling the interactions between wind and water erosion require further field investigation. It is concluded that CSE is an important but underappreciated process in semiarid regions and needs to be accounted for in land degradation assessments as it has substantial impacts on agricultural productivity and sustainable development in regions with sandy and/or loess-covered surfaces.

Published
2022

230. Developed and developing world responsibilities for historical climate change and CO₂ mitigation

Author

Wei, Ting, Yang, Shili, Moore, John C., Shi, Peijun, Cui, Xuefeng, Duan, Qingyun, Xu, Bing, Dai, Yongjiu, Yuan, Wenping, Wei, Xin, Yang, Zhipeng, Wen, Tijian, Teng, Fei, Gao, Yun, Chou, Jieming, Yan, Xiaodong, Wei, Zhigang, Guo, Yan, Jiang, Yundi, Gao, Xuejie, Wang, Kaicun, Zheng, Xiaogu, Ren, Fumin, Lv, Shihua, Yu, Yongqiang, Liu, Bin, Luo, Yong, Li, Weijing, Ji, Duoying, Feng, Jinming, Wu, Qizhong, Cheng, Huaqiong, He, Jiankun, Fu, Congbin, Ye, Duzheng, Xu, Guanhua, and Dong, Wenjie

Published
2012

240. Droughts in China

Author

Ye, Tao, primary, Jia, Huicong, additional, Lei, Yongdeng, additional, Shi, Peijun, additional, and Wang, Jing’ai, additional

Published
2016
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241. Earthquake Disasters in China

Author

Xu, Wei, primary, Liu, Jifu, additional, Xu, Guodong, additional, Wang, Ying, additional, Liu, Lianyou, additional, and Shi, Peijun, additional

Published
2016
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242. Floods in China

Author

Du, Juan, primary, Kong, Feng, additional, Du, Shiqiang, additional, Li, Ning, additional, Li, Ying, additional, and Shi, Peijun, additional

Published
2016
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244. Additional file 3 of Uncertainties of soil organic carbon stock estimation caused by paleoclimate and human footprint on the Qinghai Plateau

Author

Liu, Xia, Zhou, Tao, Shi, Peijun, Zhang, Yajie, Luo, Hui, Yu, Peixin, Xu, Yixin, Zhou, Peifang, and Zhang, Jingzhou

Subjects
GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries)
Abstract

Additional file 3. List of 58 published papers from which the data used in this study were derived.

Published
2022
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247. A Heterogeneous Sampling Strategy to Model Earthquake-Triggered Landslides

Author

Yang, Hui, Shi, Peijun, Quincey, Duncan, Qi, Wenwen, and Yang, Wentao

Abstract

Regional modeling of landslide hazards is an essential tool for the assessment and management of risk in mountain environments. Previous studies that have focused on modeling earthquake-triggered landslides report high prediction accuracies. However, it is common to use a validation strategy with an equal number of landslide and non-landslide samples, scattered homogeneously across the study area. Consequently, there are overestimations in the epicenter area, and the spatial pattern of modeled locations does not agree well with real events. In order to improve landslide hazard mapping, we proposed a spatially heterogeneous non-landslide sampling strategy by considering local ratios of landslide to non-landslide area. Coseismic landslides triggered by the 2008 Wenchuan Earthquake on the eastern Tibetan Plateau were used as an example. To assess the performance of the new strategy, we trained two random forest models that shared the same hyperparameters. The first was trained using samples from the new heterogeneous strategy, and the second used the traditional approach. In each case the spatial match between modeled and measured (interpreted) landslides was examined by scatterplot, with a 2 km-by-2 km fishnet. Although the traditional approach achieved higher AUCROC(0.95) accuracy than the proposed one (0.85), the coefficient of determination (R2) for the new strategy (0.88) was much higher than for the traditional strategy (0.55). Our results indicate that the proposed strategy outperforms the traditional one when comparing against landslide inventory data. Our work demonstrates that higher prediction accuracies in landslide hazard modeling may be deceptive, and validation of the modeled spatial pattern should be prioritized. The proposed method may also be used to improve the mapping of precipitation-induced landslides. Application of the proposed strategy could benefit precise assessment of landslide risks in mountain environments.

Published
2023
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