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Research in Cold and Arid Regions 2022年第1期14卷 43-53页

作者： CaiXia Zhang jinchang li Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China Shanxi Laboratory for Yellow River Institute of Loess PlateauShanxi UniversityTaiyuanShanxi 030006China

Samples from the Horqin sandy land were exposed to a series of wind velocities,and sink particles were collected at the end of the diffusion section of a wind tunnel.Grain sizes of collected samples show great variation because of the granularity difference of the surface samples.The original samples show lower average content of SiO_(2) and higher average content of Al _(2)O_(3),Fe_(2)O_(3),MgO,CaO,Na_(2)O,and K_(2)O than collected samples.Compared with other dust source areas in China,the Horqin sandy land had higher content of Zr,Ba,SiO_(2),Al_(2)O_(3) and K_(2)O.Compared with the average upper continental crust(UCC)composition,surface samples were rich in the content of Y,Zr,Nb,Ba,La,Nd.Geochemistry characteristics of fine grain components of the Horqin sandy land differ from those from other dust source regions,because fine-grained particles in the Horqin sandy land were mostly derived from various local deposits formed in its unique depositional environments influenced by several tectonic activities.

关键词： sink sand wind erosion aeolian process Horqin sandy land

Elemental composition and its environmental significance for the varicolored hills in the northern foothills of the Qilian Mountains of Sunan Yugur Autonomous County,China

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Research in Cold and Arid Regions 2015年第3期7卷 257-264页

作者： CaiXia Zhang XiaoZe li Zhong Sun jinchang li Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Institute of Loess Plateau Shanxi University

The varicolored hills in the northern foothills of the Qilian Mountains of northem China, in the Hexi Corridor of Gansu Province＇s Sunan Yugur Autonomous County, have given this region a unique geomorphology. In this paper, we describe the elemental composition, lithological characteristics, and source type of the sediments that formed the varicolored hills. We found that the major oxides that make up their sediments are SiO2, A12O3 and Na2O. These sediments had higher Fe2O3, MgO, CaO, and Na2O contents and lower SiO2, A12O3, K2O, and TiO2 contents than in the major Fangyan rock group of the Jianglang Mountains Danxia landform and the red paleosols that have accumulated in the Yaojia Formation of the Songliao Basin. The varicolored hills have developed their strong coloration as a result of oxidation or reduction of Fe. Our data suggest that the sediments developed from terrestrial detrital deposits.The varicolored hills in the northern foothills of the Qilian Mountains of northem China, in the Hexi Corridor of Gansu Province＇s Sunan Yugur Autonomous County, have given this region a unique geomorphology. In this paper, we describe the elemental composition, lithological characteristics, and source type of the sediments that formed the varicolored hills. We found that the major oxides that make up their sediments are SiO2, A12O3 and Na2O. These sediments had higher Fe2O3, MgO, CaO, and Na2O contents and lower SiO2, A12O3, K2O, and TiO2 contents than in the major Fangyan rock group of the Jianglang Mountains Danxia landform and the red paleosols that have accumulated in the Yaojia Formation of the Songliao Basin. The varicolored hills have developed their strong coloration as a result of oxidation or reduction of Fe. Our data suggest that the sediments developed from terrestrial detrital deposits.

关键词： red bed varicolored hills Hexi Corridor Qilian Mountains

Single-Index Quantile Regression with Left Truncated Data

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Journal of Systems Science & Complexity 2022年第5期35卷 1963-1987页

作者： XU Hongxia FAN Guoliang li jinchang Department of Mathematics Shanghai Maritime UniversityShanghai 201306China School of Data Sciences Zhejiang University of Finance and EconomicsHangzhou 310018China School of Economics and Management Shanghai Maritime UniversityShanghai 201306China

The purpose of this paper is two fold.First,the authors investigate quantile regression(QR)estimation for single-index QR models when the response is subject to random left truncation.The random weights are introduced to deal with left truncated data and the associated iteration estimation method is proposed.The asymptotic properties for the proposed QR estimates of the index parameter and unknown link function are both obtained.Further,by combining the QR loss function and the adaptive LASSO penalization,a variable selection procedure for the index parameter is introduced and its oracle property is established.Second,a weighted empirical log-likelihood ratio of the index parameter based on the QR method is introduced and is proved to be asymptotic standard chi-square distribution.Furthermore,confidence regions of the index parameter can be constructed.The finite sample performance of the proposed methods are demonstrated.A real data analysis is also conducted to show the usefulness of the proposed approaches.

关键词： Adaptive LASSO penalty left truncated data quantile regression single-index model variable selection

Land use and land cover change processes in China's eastern Loess Plateau

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Research in Cold and Arid Regions 2015年第6期7卷 722-729页

作者： jinchang li HaiXia liu Yong liu ZhiZhu Su ZiQiang Du Institute of Loess Plateau Shanxi University Historical Culture School Shanxi University

Using Landsat remote sensing images, we analyzed changes in each land use type and transitions among different land use types during land use and land cover change （LUCC） in Ningwu County, located in the eastern Loess Plateau of China, from 1990 to 2010. We found that grassland, woodland, and farmland were the main land use types in the study area, and the area of each type changed slightly from 1990 to 2010, whereas the area of water, construction land, and unused land increased greatly. For the whole area, the net change and total change were insignificant due to weak human activity intensity in most of the study area, and the LUCC was dominated by quasi-balanced two-way transitions from 1990 to 2010. The insignificant overall amount of LUCC appears to have resulted from offsetting of rapid increases in population, economic growth, and the im- plementation of a program to return farmland to woodland and grassland in 2000. This program converted more farmland into woodland and grassland from 2000 to 2010 than from 1990 to 2000, but reclamation of woodland and grassland for use as farmland continued from 2000 to 2010, and is a cause for concern to the local government.

关键词： land use and land cover change remote sensing forest restoration Ningwu County Loess Plateau

Characterizing changes in ecosystem service values in China's eastern Loess Plateau

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Research in Cold and Arid Regions 2015年第3期7卷 272-281页

作者： jinchang li HaiXia liu ZhiZhu Su Yong liu YongGang Yang Institute of Loess Plateau Shanxi University Historical Culture School Shanxi University

Human activities such as the implementation of ecological protection projects and expansion of construction land can cause complex land use changes that affect ecosystem service values （ESV）. In this study, we investigated changes in ESV in response to land use changes in Ningwu County, in eastern Loess Plateau of China. Our aim is to provide guidance for sustainable land use planning in this region. We used remote sensing to evaluate land use changes, and applied a fast, proxy-based method for evaluating ESVat three points in time： 1990, 2000, and 2010. More than 89% of the total ESV in Ningwu County was attributable to woodland and grassland. The ESV in western mountain areas show the greatest increase from 1990 to 2010, but ESV decreased the most in the low-elevation northeastern area of flat terrain These tradeoffs led to a slight net decrease （1.0%） in Ningwu County＇s total ESV. Although the decline in ESV was relatively low compared to the rate of economic growth, total ESV was much lower than global and national average levels at the end of the study period.

关键词： ecosystem service values land use changes ecological protection projects remote sensing Ningwu County

Seasonal variation in dust events and the causes of the variation in the Tarim Basin,China

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Research in Cold and Arid Regions 2009年第2期1卷 143-150页

作者： jinchang li ZhiBao Dong ShuSheng He Institute of Loess Plateau Shanxi UniversityTaiyuan 030006China. Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China.

We analyzed dust event occurrence and its seasonal distribution at 16 sites in the Tarim Basin,China.Although the overall frequency of dust events was the highest in spring in this region,its variation in other seasons could be classified into three patterns:(1) frequency of dust events in autumn > that in summer > that in winter(at the Kashi and Kuche sites);(2) frequency in summer > that in winter > that in autumn(at the Ruoqiang site);and(3) frequency in summer > that in autumn > that in winter(at all other areas of the Tarim Basin).The frequency of dust events and their seasonal variations in the Tarim Basin were mainly controlled by wind speed and locally available dust sources;the former was the key control when dust sources did not differ significantly.The seasonal variation in evaporation had a smaller,but still significant effect on the frequency of dust events.

关键词： Tarim Basin dust events seasonal variation sand-blowing wind

Spatial trends of dustfall over northern China in the spring and their influencing factors

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Research in Cold and Arid Regions 2010年第6期2卷 529-537页

作者： jinchang li ZhiBao Dong GuangQiang Qian WanYin Luo Institute of Loess Plateau Shanxi UniversityTaiyuanShanxi 030006China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of ScienceLanzhouGansu 730000China

The spatial trends of dustfall of different sizes over northern China during April and May 2001,and March 2002,and their influencing factors,were analyzed.We divided the dustfall into seven grades based on particle size.Total dustfall and dustfall for each grade were highest in desert regions then in regions undergoing desertification,and the total dustfall,dustfall 250 μm were higher in western agricultural regions closer to desert areas than in eastern agricultural regions.The spatial trends in dustfall ling factors as dust events,but the control decreases with increasing particle size.Wind,the driving force for dust emissions,also influenced the spatial trends in dustfall lity that this dust is entrained mainly by the small-scale dust devils that are commonly observed in the study area.

关键词： dustfall desertification spatial trends dust events geomorphic conditions Northern China

Aeolian dust transportation and deposition by near-surface winds in arid and semiarid China

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Research in Cold and Arid Regions 2010年第2期2卷 137-142页

Dustfall collections were carried out in April and May 2001 and in March 2002 at six sites in northern China.Our results showed that the total deposition of dust fractions <250 μm in diameter and the deposition of Fe... 详细信息

Dustfall collections were carried out in April and May 2001 and in March 2002 at six sites in northern China.Our results showed that the total deposition of dust fractions little longer than that of total dust deposition,which suggests that the Fe content is higher in fine particles than in coarse particles,as previous studies have suggested.In addition,our analysis showed that under the control of current climatic conditions,the coarse fractions in dust derived from northwestern China cannot be transported over long distances,instead,it is transported primarily by near-surface winds (lian dust generated from arid and semiarid regions of China and deposited in the North Pacific region is usually transported by the upper westerlies.

关键词： dust deposition half-attenuation distance near-surface wind arid and semiarid regions of China

Effects of geomorphic conditions, wind speed, and precipitation on dustfall over northern China

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Research in Cold and Arid Regions 2010年第4期2卷 354-363页

We investigated how dustfall flux (DF) and dust particle size (DPS) were affected by geomorphic conditions, wind speed, and precipitation using data from 27 sites in northern China. The sites with the greatest DF and greatest median diameter of dustfall (MDD) were primarily in desert regions and had extensive mobile sands. DF and MDD were lowest in agricultural regions, which had low levels of coarse particles because of human land use and high vegetation coverage that restrained blowing sand. DF values were higher and MDD values were lower in the western agricultural region than in the eastern agricultural region because the former is closer to desert regions and contains more fine dust that has traveled far. In regions with extensive desertified lands, DF values were lower than those in desert regions, and MDD values were greater than in agricultural regions, possibly due to coarsening of soil texture by desertification processes combined with higher vegetation coverage and soil moisture than in desert regions, thereby restraining blowing sand. Although high DF and MDD always coincided spatially with strong winds and low precipitation, the strong winds and low precipitation did not always mean high DF and MDD. High DF also coincided temporally with periods of low precipitation, but low precipitation did not always mean high DF. Thus, although the spatial trends in DF and DPS were controlled mostly by geomorphic conditions, and monthly trends in DF were controlled mainly by wind speed, weak wind and high precipitation can restrain the blowing sand at certain times and locations. Seasonal changes in DPS may be controlled simultaneously by geomorphic conditions, meteorological factors, and distance from source areas, not solely by the winter monsoon.

关键词： dustfall flux grain size geomorphic conditions wind speed northern China

Visual Analytics of Large-scale E-government Text Data via Simplified Word Cloud

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Data Science and Informetrics 2021年第1期1卷 29-51页

作者： Yanan liu Fang He Jin Wen Zhiguang Zhou jinchang li School of Information Zhejiang University of Finance and EconomicsHangzhouChina School of Data Sciences Zhejiang University of Finance and EconomicsHangzhouChina State Key Laboratory of CAD&CG Zhejiang UniversityHangzhouChina

With the rapid development of Internet technology,a rich set of e-government data are collected by the government departments.For example,a variety of feedback text data can be obtained quickly and efficiently through various channels such as the mayor’s mailbox.It is an effective way to improve the working efficiency of the government to extract hot topics from large-scale e-government text data,establish the correlation between topics and geographic space,and interactively explore the sources of public feedback problems.However,it is a difficult task to explore the large-scale e-government text data with traditional visualization methods such as word cloud,because too many words are hardly distributed in a limited space which will largely disturb the visual perception.In this paper,we propose a visual analytics system for large-scale e-government data exploration by means of simplified word cloud.Firstly,a representation learning model is used to embed the text data into high-dimensional space to quantitatively represent the semantic structure features of e-government text data.Then,the high-dimensional vectors are projected into a two-dimensional space where the coordinate distribution of points effectively expresses the semantic similarity of original words,which also presents geographic features that can be quantized by means of a similarity computing model.In order to simplify the understanding of large-scale e-government data and improve the cognitive efficiency of word could,we adopt the adaptive blue noise method to sample the topic words,which can simplify the visual expression of word cloud and improve the understanding efficiency of e-government data without losing the semantic structure features.Furthermore,an abstraction and visual analysis system for large-scale e-government text data is designed and implemented by integrating the above representation learning model,sampling-based abstraction model of word cloud,and topic and geographic correlation analysis model.This system provides convenient hum

关键词： E-government Text mining Text visualization Visual analytics