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Quantifying spatial scale of positive and negative terrains pattern at watershed-scale:Case in soil and water conservation region on Loess Plateau

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Journal of Mountain Science 2017年第8期14卷 1642-1654页

作者： YANG Feng ZHOU Yi school of geography and tourism Shaanxi Normal University

The positive and negative terrains(P-N terrains) widely distributed across China's Loess Plateau constitute the dual structure characteristic of loess landforms. Analysis of loess P-N terrains at the watershed scale can serve to elucidate the structural characteristics and spatial patterns of P-N terrains, which benefits a better understanding of watershed evolution and suitable scales for loess landform research. The Two-Term Local Quadrat Variance Analysis(TTLQV) is calculated as the average of the square of the difference between the block totals of all possible adjacent pairs of block size, which can be used to detect both the scale and the intensity of landscape patches(e.g., plant/animal communities and gully networks). In this study, we determined the latitudinal and longitudinal spatial scale of P-N terrain patterns within 104 uniformly distributed watersheds in our target soil and water conservation region. The results showed that TTLQV is very effective for examining the scale of P-N terrain patterns. There were apparently three types of P-N terrain pattern in latitudinal direction(i.e., Loess Tableland type, Loess Hill type, and Transitional Form between Sand and Loess type), whereas there were both lower and higher values for P-N terrain pattern scales in all loess landforms in the longitudinal direction. The P-N terrain pattern alsoclearly presented anisotropy, suggesting that gully networks in the main direction were well-developed while others were relatively undeveloped. In addition, the relationships between the first scales and controlling factors(i.e., gully density, nibble degree, watershed area, mean watershed slope, NDVI, precipitation, loess thickness, and loess landforms) revealed that the first scales are primarily controlled by watershed area and loess landforms. This may indicate that the current spatial pattern of P-N terrains is characterized by internal force. In selecting suitable study areas in China' Loess Plateau, it is crucial to u

关键词： Positive and negative terrains TTLQV Spatial pattern scale Loess landforms Loess Plateau

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Changes in the depths of seasonal freezing and thawing and their effects on vegetation in the Three-River Headwater Region of the Tibetan Plateau

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Journal of Mountain Science 2019年第12期16卷 2810-2827页

作者： WANG Rui DONG Zhi-bao ZHOU Zheng-chao school of geography and tourism Shaanxi Normal University

Frozen ground degradation plays an important role in vegetation growth and activity in high-altitude cold *** study estimated the spatiotemporal variations in the active layer thickness(ALT)of the permafrost region and the soil freeze depth(SFD)in the seasonally frozen ground region across the Three Rivers Source Region(TRSR)from 1980 to 2014 using the Stefan equation,and differentiated the effects of these variations on alpine vegetation in these two *** results showed that the average ALT from 1980 to 2014 increased by23.01 cm/10 a,while the average SFD decreased by 3.41 cm/10 a,and both changed intensively in the transitional zone between the seasonally frozen ground and *** 1982-2014,the increase in the normalized difference vegetation index(NDVI)and the advancement of the start of the vegetation growing season(SOS)in the seasonally frozen ground region(0.0078/10 a,1.83 d/10 a)were greater than those in the permafrost region(0.0057/10 a,0.39 d/10 a).The results of the correlation analysis indicated that increases in the ALT and decreases in the SFD in the TRSR could lead to increases in the NDVI and advancement of the *** soil moisture played a critical role in vegetation growth in association with the increasing ALT and decreasing *** NDVI for all vegetation types in the TRSR except for alpine vegetation showed an increasing trend that was significantly related to the SFD and *** the study period,the general frozen ground conditions were favorable to vegetation growth,while the average contributions of ALT and SFD to the interannual variation in the NDVI were greater than that of precipitation but less than that of temperature.

关键词： Frozen soil depth Active layer thickness Alpine vegetation Climate warming Three Rivers Source Region

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Impact of land use/land cover types on surface humidity in northern China in the early 21^(st)century

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Journal of Arid Land 2022年第7期14卷 705-718页

作者： JIN Junfang YIN Shuyan YIN Hanmin school of geography and tourism Shaanxi Normal UniversityXi'an 710119China Xinjiang Institute of Ecology and geography Chinese Academy of SciencesUrumqi 830011China

In the context of global change,it is essential to promote the rational development and utilization of land resources,improve the quality of regional ecological environment,and promote the harmonious development of human and nature for the regional *** identified land use/land cover types in northern China from 2001 to 2018 with ENVI images and ArcGIS *** data were selected from 292 stations in northern China,the potential evapotranspiration was calculated with the Penman-Monteith formula,and reanalysis humidity and observed humidity data were *** reanalysis minus observation(RMO,i.e.,the difference between reanalysis humidity and observed humidity)can effectively characterize the impact of different land use/land cover types(forestland,grassland,cultivated land,construction land,water body and unused land)on surface humidity in northern China in the early 21^(st) *** results showed that from 2001 to 2018,the area of forestland expanded(increasing by approximately 1.80×10^(4) km^(2)),while that of unused land reduced(decreasing by approximately 5.15×10^(4) km^(2)),and the regional ecological environment was ***,land surface in most areas of northern China tended to be *** contributions of land use/land cover types to surface humidity changes were related to the quality of the regional ecological *** contributions of the six land use/land cover types to surface humidity were the highest in northeastern region of northern China,with a better ecological environment,and the lowest in northwestern region,with a fragile ecological *** humidity was closely related to the variation in regional vegetation coverage;when the regional vegetation coverage with positive(negative)contributions expanded(reduced),the land surface became *** positive contributions of forestland and water body to surface humidity were the *** land and construction land were associ

关键词： surface humidity land use/land cover change reanalysis minus observation Penman-Monteith formula climate change northern China

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Evaluation on tourism Ecological Security in Nature Heritage Sites——Case of Kanas Nature Reserve of Xinjiang,China

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Chinese Geographical Science 2009年第3期19卷 265-273页

作者： LIU Xuling YANG Zhaoping DI Feng CHEN Xuegang tourism school Xinjiang University of Finance ＆ Economics Urumqi 830012 China Xinjiang Institute of Ecology and geography Chinese Academy of Sciences Urumqi 830011 China school of geography Science and tourism Xinjiang Normal University Urumqi 830054 China

The nature heritages are the precious legacy of nature with outstanding scientific and aesthetic value. They are quite different from other common ecotourism areas, because of its original and unique system, sensitive and vulnerable landscape, and peripheral cultural features. Therefore, the tourism development in the nature heritage sites should be on the premise of ecological security. The evaluation index system of tourism ecological security in nature heritage sites was constructed in this article by AHP and Delphi methods, including nature ecological security, landscape visual security and local culture ecological security, and the security thresholds of indices were also established. In the indices' weights of the evaluation model, the nature ecological security ranked the highest, followed by tourist landscape visual security and culture ecological security, which reflected the influence degree of the limited factor to tourism ecological security. Then, this paper carried out an empirical study of Kanas of Xinjiang Uygur Autonomous Region, China, which has the potential to be the World Nature Heritage. On the basis of the data attained from survey and observation on the spot, as well as questionnaire answered by tourists and local communities, the ecological security status in Kanas was evaluated. The result showed that the status of Kanas tourism ecological security was better, but there had some limiting factors. Lastly, effective measures were put forward to ensure its ecological security.

关键词： nature heritage tourism ecological security nature ecological security landscape visual security local culture ecological security Kanas

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Sand and Dust Storm Risk Assessment in Arid Central Asia: Implications for the Environment, Society, and Agriculture

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International Journal of Disaster Risk Science 2024年第5期15卷 703-718页

作者： Wei Wang Shanfeng He Hao Guo Jilili Abuduwaili Alim Samat Philippe De Maeyer Tim Van de Voorde school of geography and tourism Qufu Normal University Sino-Belgian Joint Laboratory of Geo-information Xinjiang Institute of Ecology and geography Chinese Academy of Sciences Department of geography Ghent University

This study aimed to assess sand and dust storm(SDS) risks in arid Central Asia during 2001–2021 from a multisectoral(environment, society, and agriculture) and comprehensive perspective on the Google Earth Engine(GEE) platform. The results show that the areas with moderate or greater SDS risk accounted for 18.75% of the total area of arid Central Asia. The high SDS risk areas are mainly concentrated in the oases around the desert and are most widely distributed in spring and summer. The SDS risk in the oasis area of southern Xinjiang increased significantly, while the SDS risk in the northeastern Aral Sea region and the Kazakh hilly region decreased significantly over the 21 years. Khwarazm of Uzbekistan, located in the Amu Darya River Delta, is the administrative district with the highest comprehensive risk of sandstorms, and the Balkan State of Turkmenistan and Kashi City and Zepu County in China are the administrative districts with the highest multisectoral risk of sandstorms. The results of this study provide a complete picture of SDS risks in the arid Central Asia region and will provide some guidance to policymakers and local authorities in SDS risk mitigation.

关键词： Analytic hierarchy process Central Asia Multisectoral risk assessment Remote sensing Sand and dust storms

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Predicting and assessing changes in NPP based on multi-scenario land use and cover simulations on the Loess Plateau

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Journal of Geographical sciences 2021年第7期31卷 977-996页

作者： JIANG Xiaowei BAI Jianjun school of geography and tourism Shaanxi Normal UniversityXi'an 710119China

Land use/cover change(LUCC)is a major factor affecting net primary production(NPP).According to the LUCC of the Loess Plateau from 2005 to 2015,the LUCC patterns in 2025 in three scenarios were predicted by using the Future Land Use Simulation(FLUS)***,taking the average NPP of various land use/cover types in 16 years as the reference scale,the changes in NPP in multi-scenario simulations are predicted and analyzed,and the impact of different land use/cover transfers on NPP is *** results are as follows:(1)The land use/cover changes greatly in the baseline and fast development scenarios,and changes relatively little in the ecological protection scenarios.(2)The changes in NPP in different scenarios reflected the significant difference in the ecological protection *** the three scenarios promote an NPP increase,but the ecological protection scenario can promote NPP increases the most.(3)The changes in NPP caused by LUCC in the three scenarios reflected the significant difference in the various land use/cover types protection *** and predicting NPP changes in multi-scenario LUCC simulations in the future can provide a theoretical basis for decision makers to judge the future changes in ecological environments and ecological protection effects against different policy backgrounds.

关键词： net primary production(NPP) scenario simulation land use/cover change(LUCC) Loess Plateau

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The spatio-temporal heterogeneity of county-level economic development and primary drivers across the Loess Plateau,China

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Journal of Geographical sciences 2021年第3期31卷 423-436页

作者： LIU Shijun XUE Liang school of geography and tourism Shaanxi Normal UniversityXi'an 710119China

Unbalanced economic growth is a ubiquitous phenomenon while investigating the regional development at a large spatial ***,it is of great significance to analyze the spatio-temporal pattern of regional economic growth and the drivers to understand and facilitate the economic development of low development *** a county as a fundamental study unit,we used the county-level per capita GDP data on the Loess Plateau from 2005 to 2017,and geographic variables such as slope,elevation,and population density to analyze the spatio-temporal differences and the driving factors of the county-level economic development in the Loess Plateau by employing both conventional and advanced quantitative methods including Exploratory Spatial Data Analysis(ESDA)and the geographic detector *** results suggested that:(1)The selected indicators,including absolute difference,the fluctuation of relative difference and total difference of economic development on the Loess Plateau,all show steady increasing trends,respectively.(2)There are 64.5%of the counties with economic development being below the average level of the whole Loss Plateau *** relatively high developed counties are distributed in the"A"-shaped regions in Inner Mongolia Autonomous Region,Shaanxi,and Henan provinces,however,the low development counties are mainly located in the"V"-shaped regions in Gansu and Shanxi provinces.(3)GDP,investment in fixed assets and urbanization rate are the major driving factors influencing the regional economic development,and the combined effects are far greater than that of any individual factor.

关键词： county economic development difference driving factor Loess Plateau

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Quantitative assessment of the spatial distribution of^(239+240)Pu inventory derived from global fallout in soils from Asia and Europe

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Journal of Geographical sciences 2022年第4期32卷 605-616页

作者： CAO Liguo ZHOU Zhengchao WANG Ning XIAO Shun school of geography and tourism Shaanxi Normal UniversityXi'an 710119China

Due to the atmospheric nuclear weapon tests carried out,terrestrial environments have been extensively contaminated by global fallout of plutonium(Pu)***^(239+240)Pu inventories in soil profiles from undisturbed and flat forest or grasslands(reference sites)mainly from Europe and Asia are considered as important background for evaluating soil ***,we conducted a literature survey over an area extending from 2.6°W to 148.9°E and from 53.2°S to 76.6°N,with the purpose of analyzing the spatial distribution of^(239+240)Pu inventories and possible controlling *** aim of this work was to derive an empirical model of^(239+240)Pu inventory based on currently available^(239+240)Pu data,precipitation and *** results show that,in general,the latitudinal distribution of^(239+240)Pu inventory was consistent with the UNSCEAR ***,the^(239+240)Pu inventories are higher than the UNSCEAR data,especially in the Northern *** addition,close relationships(at the 0.01 significance level)were identified between^(239+240)Pu inventories and annual precipitation and *** empirical formula was therefore developed to estimate^(239+240)Pu inventories in soils based on latitude and precipitation ***,future research may require more data of measured^(239+240)Pu inventories in soil profiles that can be used to compare,validate and improve upon the accuracy of the inferred empirical equation.

关键词： spatial distribution plutonium global fallout precipitation

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Projected Regional 1.50℃and 2.00℃Warming Threshold-crossing Time Worldwide Using the CMIP6 Models

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Chinese Geographical Science 2023年第6期33卷 1095-1108页

作者： MENG Yali DUAN Keqin SHANG Wei SHI Peihong LI Shuangshuang CHENG Ying CHEN Rong ZHANG Zhaopeng school of geography and tourism Shaanxi Normal UniversityXi’an710119China

The Paris Agreement aims to limit global warming to well below 2.00℃and pursue efforts to limit the temperature increase to 1.50℃.However,the response of climate change to unbalanced global warming is affected by spatial and temporal *** better understand the regional warming response to global warming at 1.50℃and 2.00℃,we detected the 1.50℃and 2.00℃warming threshold-crossing time(WTT)above pre-industrial levels globally using the Coupled Model Intercomparison Project phase 6(CMIP6)*** findings indicate that the 1.50℃or 2.00℃WTT differs substantially *** warming rate of land would be approximately 1.35–1.46 times that of the ocean between 60°N–60°S in 2015–***,the land would experience a 1.50℃(2.00℃)warming at least 10–20 yr earlier than the time when the global mean near-surface air temperature reaches 1.50℃(2.00℃)***,the Southern Ocean between 0°and 60°S considerably slows down the global 1.50℃and 2.00℃*** 2040–2060,over 98.70%(77.50%),99.70%(89.30%),99.80%(93.40%),and 100.00%(98.00%)of the land will have warmed by over 1.50℃(2.00℃)under SSP(Shared Socioeconomic Pathway)1–2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5,*** conclude that regional 1.50℃(2.00℃)WTT should be fully considered,especially in vulnerable high-latitude and high-altitude regions.

关键词： CMIP6(Coupled Model Intercomparison Project phase 6) global warming 1.50℃warming time 2.00℃warming time regional differences

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Different Responses of Vegetation to Frozen Ground Degradation in the Source Region of the Yellow River from 1980 to 2018

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Chinese Geographical Science 2020年第4期30卷 557-571页

作者： WANG Rui DONG Zhibao ZHOU Zhengchao school of geography and tourism Shaanxi Normal UniversityXi'an 710119China

Frozen ground degradation under a warming climate profoundly influences the growth of alpine vegetation in the source region of the Qinghai-Tibet *** study investigated spatiotemporal variations in the frozen ground distribution,the active layer thickness(ALT)of permafrost(PF)soil and the soil freeze depth(SFD)in seasonally frozen soil from 1980 to 2018 using the temperature at the top of permafrost(TTOP)model and Stefan *** compared the effects of these variations on vegetation growth among different frozen ground types and vegetation types in the source region of the Yellow River(SRYR).The results showed that approximately half of the PF area(20.37%of the SRYR)was projected to degrade into seasonally frozen ground(SFG)during the past four decades;furthermore,the areal average ALT increased by 3.47 cm/yr,and the areal average SFD decreased by 0.93 cm/yr from 1980 to ***,the growing season Normalized Difference Vegetation Index(NDVI)presented an increasing trend of 0.002/10 yr,and the increase rate and proportion of areas with NDVI increase were largest in the transition zone where PF degraded to SFG(the PF to SFG zone).A correlation analysis indicated that variations in ALT and SFD in the SRYR were significantly correlated with increases of NDVI in the growing ***,a rapid decrease in SFD(<-1.4 cm/10 yr)could have reduced the soil moisture and,thus,decreased the *** NDVI for most vegetation types exhibited a significant positive correlation with ALT and a negative correlation with ***,the steppe NDVI exhibited a significant negative correlation with the SFD in the PF to SFG zone but a positive correlation in the SFG zone,which was mainly limited by water condition because of different change rates of the SFD.

关键词： permafrost seasonally frozen ground vegetation dynamics climate change source region of the Yellow River

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