Soil Susceptibility to Macropore Flow Across a Desert-Oasis Ecotone of the Hexi Corridor, Northwest China

2018 ◽  
Vol 54 (2) ◽  
pp. 1281-1294 ◽  
Author(s):  
Yongyong Zhang ◽  
Wenzhi Zhao ◽  
Jianhua He ◽  
Li Fu
Keyword(s):  
Northwest China ◽  
Hexi Corridor ◽  
Macropore Flow ◽  
Desert Oasis

scholarly journals Multi-Temporal Arable Land Monitoring in Arid Region of Northwest China Using a New Extraction Index

2021 ◽  
Vol 13 (9) ◽  
pp. 5274
Author(s):  
Xinyang Yu ◽  
Younggu Her ◽  
Xicun Zhu ◽  
Changhe Lu ◽  
Xuefei Li
Keyword(s):  
Arable Land ◽  
Ground Truth ◽  
Northwest China ◽  
Hexi Corridor ◽  
Ground Truth Data ◽  
Land Protection ◽  
Promising Tool ◽  
Study Results ◽  
Multi Temporal ◽  
The Mean

Development of a high-accuracy method to extract arable land using effective data sources is crucial to detect and monitor arable land dynamics, servicing land protection and sustainable development. In this study, a new arable land extraction index (ALEI) based on spectral analysis was proposed, examined by ground truth data, and then applied to the Hexi Corridor in northwest China. The arable land and its change patterns during 1990–2020 were extracted and identified using 40 Landsat TM/OLI images acquired in 1990, 2000, 2010, and 2020. The results demonstrated that the proposed method can distinguish arable land areas accurately, with the User’s (Producer’s) accuracy and overall accuracy (kappa coefficient) exceeding 0.90 (0.88) and 0.89 (0.87), respectively. The mean relative error calculated using field survey data obtained in 2012 and 2020 was 0.169 and 0.191, respectively, indicating the feasibility of the ALEI method in arable land extracting. The study found that arable land area in the Hexi Corridor was 13217.58 km2 in 2020, significantly increased by 25.33% compared to that in 1990. At 10-year intervals, the arable land experienced different change patterns. The study results indicate that ALEI index is a promising tool used to effectively extract arable land in the arid area.

Comprehensive assessment of water security for inland watersheds in the Hexi Corridor, Northwest China

2007 ◽  
Vol 55 (2) ◽  
pp. 369-376 ◽  
Author(s):  
Sheng-chun Xiao ◽  
Jin-xiu Li ◽  
Hong-lang Xiao ◽  
Fa-min Liu
Keyword(s):  
Water Security ◽  
Northwest China ◽  
Hexi Corridor ◽  
Comprehensive Assessment

scholarly journals Analysis of land cover change and its driving forces in a desert oasis landscape of Xinjiang, northwest China

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 1071-1085 ◽  
Author(s):  
T. Amuti ◽  
G. Luo
Keyword(s):  
Land Cover ◽  
Land Degradation ◽  
Driving Forces ◽  
Northwest China ◽  
Landsat Images ◽  
Desert Oasis ◽  
Standard Classification ◽  
Effects Of Drought ◽  
Arid Desert ◽  
Southern Xinjiang

Abstract. The combined effects of drought, warming and the changes in land cover have caused severe land degradation for several decades in the extremely arid desert oases of southern Xinjiang, northwest China. Land cover classifications of Landsat images in 1990, 2000 and 2008 were performed based on the multistage supervised classification scheme using the maximum likelihood classifier integrated with conventional vegetation and soil indexes, which improved overall accuracies by 4–5% compared to the standard classification method. Based on the detection of changes in land cover during 1990–2008 using remote sensing (RS) and a geographic information system (GIS), it can be found that the oasis significantly (+35%) increased, while the area of ecotone decreased (−43%). The major trends of the land cover changes were the notable growth of the oasis and the reduction of the desert–oasis ecotone. These changes were mainly a result of the intensified human activities such as land and water exploitation as well as overgrazing. The results of this study indicate that the oasis environment will be deteriorated by increase in potential areas of land degradation if the trend of desert moving further inward and the shrinking of the ecotone continues over the next decades.

scholarly journals Abundant Precipitation in Qilian Mountains Generated from the Recycled Moisture over the Adjacent Arid Hexi Corridor, Northwest China

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3354
Author(s):  
Zhihua Zhang ◽  
Qiudong Zhao ◽  
Shiqiang Zhang
Keyword(s):  
Water Vapor ◽  
Water Cycle ◽  
Precipitable Water ◽  
Northwest China ◽  
Hexi Corridor ◽  
Qilian Mountains ◽  
Mountain Areas ◽  
Reanalysis Dataset ◽  
Weather Forecasts ◽  
Endorheic Basin

The observed precipitation was suggestive of abundant precipitation in upstream Qilian mountains and low precipitation in the downstream oasis and desert in an endorheic basin. However, precipitation in mountains generated from the recycled moisture over oasis and desert areas has rarely been studied. The climatological patterns of water vapor from 1980 to 2017 in the Qilian Mountain Region (QMR) and Hexi Corridor Region (HCR) were investigated by the European Centre for Medium-Range Weather Forecasts Interim reanalysis dataset and the Modern-Era Retrospective Analysis for Research and Application, Version 2 reanalysis dataset. The results suggest that the precipitable water content decreases from the adjacent to the mountain areas. There are two channels that transport water vapor from the HCR to the QMR in the low troposphere (surface—600 hPa), suggesting that parts of recycled moisture generated from evapotranspiration over the oasis and desert of the HCR is transported to the QMR, contributing to the abundant precipitation in the QMR. This indicates that the transport mechanism is probably because of the “cold and wet island effect” of the cryosphere in QMR. This is likely one of the essential mechanisms of the water cycle in endorheic river basins, which has rarely been reported.

Early Cretaceous redbeds from the Minle Basin, Hexi Corridor, northwest China: Mineralogy and geochemistry implications for paleoweathering, provenance, and tectonic settings

2019 ◽  
Vol 7 (2) ◽  
pp. T525-T545
Author(s):  
Yaxiong Sun ◽  
Wenlong Ding ◽  
Yang Gu ◽  
Gang Zhao ◽  
Siyu Shi ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Chemical Weathering ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Northwest China ◽  
Hexi Corridor ◽  
Sediment Supply ◽  
Compositional Variation ◽  
Tectonic Settings

Redbeds with a large thickness in the lower Cretaceous record abundant geologic information in the Minle Basin. We have conducted the paleoweathering conditions, provenance, and tectonic settings based on mineralogy and geochemistry. Our results indicate that mudstone samples are characterized by abundant illite with negligible amounts of K-feldspars and analcime. The lower part of the lower Cretaceous is rich in quartz, whereas the upper part is dominated by dolomite and analcime. We suggest that this is caused by the decreasing input of the clastic influx during the middle-late early Cretaceous. High index of compositional variation values (average 1.33) indicate first-cycle sediment supply, suggesting an overall compositional immaturity and short-distance transportation. These characteristics are consistent with an active regional extension tectonic setting. The [Formula: see text] system ([Formula: see text];[Formula: see text];[Formula: see text]) and Th/U versus Th consistently reveal that the lower Cretaceous experienced a positive gradient in chemical weathering from young to old formations. Although the patterns of trace elements in three formations of the lower Cretaceous are different, those of the rare earth elements (REEs) tend to be consistent. The significant enrichment of light REEs, heavy REEs fractionation, and distinctive negative Eu anomalies suggest derivation from an old, upper continental crust composed of predominantly felsic sediments. This interpretation is supported by several discrimination diagrams such as titanium dioxide-nickel ([Formula: see text]), which shows the characteristics of immature recycled sediments. A few sensitive elements, ratios, and normalized REE patterns indicate a provenance of an active continental margin and a continental island arc (CIA). The La-Th-Sc, Th-Co-Zr/10, and Th-Sc-Zr/10 discrimination plots further confirm the CIA signature. Thus, we conclude that the early Cretaceous redbeds in the Minle Basin, Hexi Corridor, were deposited in a dustpan-shaped half-graben basin in a CIA setting when northwest China was influenced by intense regional extension.

scholarly journals Water Productivity Evaluation under Multi-GCM Projections of Climate Change in Oases of the Heihe River Basin, Northwest China

2019 ◽  
Vol 16 (10) ◽  
pp. 1706 ◽  
Author(s):  
Liu Liu ◽  
Zezhong Guo ◽  
Guanhua Huang ◽  
Ruotong Wang
Keyword(s):  
Climate Change ◽  
Sustainable Development ◽  
River Basin ◽  
Water Productivity ◽  
Northwest China ◽  
Hexi Corridor ◽  
Heihe River Basin ◽  
Heihe River ◽  
Crop Water ◽  
The Heihe River Basin

As the second largest inland river basin situated in the middle of the Hexi Corridor, Northwest China, the Heihe River basin (HRB) has been facing a severe water shortage problem, which seriously restricts its green and sustainable development. The evaluation of climate change impact on water productivity inferred by crop yield and actual evapotranspiration is of significant importance for water-saving in agricultural regions. In this study, the multi-model projections of climate change under the three Representative Concentration Pathways emission scenarios (RCP2.6, RCP4.5, RCP8.5) were used to drive an agro-hydrological model to evaluate the crop water productivity in the middle irrigated oases of the HRB from 2021–2050. Compared with the water productivity simulation based on field experiments during 2012–2015, the projected water productivity in the two typical agricultural areas (Gaotai and Ganzhou) both exhibited an increasing trend in the future 30 years, which was mainly attributed to the significant decrease of the crop water consumption. The water productivity in the Gaotai area under the three RCP scenarios during 2021–2050 increased by 9.2%, 14.3%, and 11.8%, while the water productivity increased by 15.4%, 21.6%, and 19.9% in the Ganzhou area, respectively. The findings can provide useful information on the Hexi Corridor and the Belt and Road to policy-makers and stakeholders for sustainable development of the water-ecosystem-economy system.

Declining Singapore — a 21st Century Dunhuang in the Making?

2018 ◽  
Vol 01 (02) ◽  
pp. 1850012
Author(s):  
Vincent F. Yip
Keyword(s):  
21St Century ◽  
Conflicts Of Interest ◽  
Northwest China ◽  
Silk Road ◽  
Belt And Road Initiative ◽  
Strategic Response ◽  
Existential Crisis ◽  
Desert Oasis ◽  
Belt And Road

Singapore is currently facing economic realities and geo-political headwinds that bear many similarities to those that brought about the decline and eventual obsolescence of Dunhuang, the desert oasis city in northwest China that once served as the strategic fulcrum of the prosperous Silk Road, connecting East and West for more than a thousand years. Ideological differences and practical conflicts of interest with an emerging China threaten to sideline Singapore and even render it irrelevant as China continues to pursue its ambitious Belt and Road Initiative. Singapore is experiencing an existential crisis unlike any it has encountered in its past 53 years of independence. A prudent strategic response would be for Singapore to emulate the Swiss model of political balance among nations, maintain its traditional neutrality and rely on its unique strategic/economic strengths in order to ensure the small republic’s survival and long-term prosperity in a region facing tumultuous upheavals in the remainder of the 21st century.

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