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A case study of regional eco-hydrological characteristics in the Tao River Basin, northwestern china, based on evapotranspiration estimated by a coupled Budyko Equation-crop coefficient approach

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science china Earth sciences 2015年第11期58卷 2103-2112页

作者： LI ChangBin ZHANG XueLei QI JiaGuo WANG shuaiBing YANG Linshan YANG WenJin ZHU GaoFeng HAO Qiang key laboratory of western china’s environmental systems (Ministry of Education) Lanzhou University Center for Global Change and Earth Observations Michigan State University Ocean College Zhejiang University

In a case study in Tao River Basin, china, we derived a high spatial-resolution regional distribution of evapotranspiration(ET) using the single crop coefficient method and Budyko equation. We then further analyzed the spatio-temporal characteristics of this diverse eco-hydrological basin from 2001–2010. The results suggest that the single crop coefficient method based on leaf area index captures better spatial and temporal dynamics of the regional ET than did the Budyko Equation method. The rising temperature was the main reason for the increasing ET in the Tao River Basin during 2001–2010. Areas with high ET efficiency were distributed mainly in the areas where the vegetation coverage was high, and a lower runoff coefficient responded. The estimated spatial patterns of ET allowed an improved understanding of the eco-hydrological processes within the Tao River Basin and the method used might be generalized as a reference for future regional-scale eco-hydrological research.

关键词： evapotranspiration Budyko Equation single crop coefficient eco-hydrology Tao River Basin

Modelling plant canopy effects on water-heat exchange in the freezingthawing processes of active layer on the Qinghai-Tibet Plateau

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Journal of Mountain science 2021年第6期18卷 1564-1579页

作者： GUO Lin-mao CHANG Juan XU Hong-liang sUN Wen-jun key laboratory of western china's environmental systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China state key laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610000China

The effect of vegetation on the water-heat exchange in the freezing-thawing processes of active layer is one of the key issues in the study of land surface processes and in predicting the response of alpine ecosystems to climate change in permafrost regions. In this study, we used the simultaneous heat and water model to investigate the effects of plant canopy on surface and subsurface hydrothermal dynamics in the Fenghuoshan area of the QinghaiTibet Plateau by changing the leaf area index(LAI) and keeping other variables constant. Results showed that the sensible heat, latent heat and net radiation are increased with an increase in the LAI. However, the ground heat flux decreased with an increasing LAI. The annual total evapotranspiration and vegetation transpiration ranged from-16% to 9% and-100% to 15%, respectively, in response to extremes of doubled and zero LAI, respectively. There was a negative feedback between vegetation and the volumetric unfrozen water content at 0.2 m through changing evapotranspiration. The simulation results of soil temperature and moisture suggest that better vegetation conditions are conducive to maintaining the thermal stability of the underlying permafrost, and the advanced initial thawing time and increasing thawing rate of soil ice with the increase in the LAI may have a great influence on the timing and magnitude of supra-permafrost groundwater. This study quantifies the impact of vegetation change on surface and subsurface hydrothermal processes and provides a basic understanding for evaluating the impact of vegetation degradation on the water-heat exchange in permafrost regions under climate change.

关键词： Permafrost simultaneous heat and water model Leaf area index Water-Heat exchange Thermal-moisture dynamics

Toward photocatalytic hydrogen generation over BiVO_(4) by controlling particle size

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Chinese Chemical Letters 2021年第8期32卷 2419-2422页

作者： Mengdi sun Zemin Zhang Qiujin shi Jianlong Yang Mingzheng Xie Weihua Han key laboratory of western china's environmental systems of the Ministry of Education Key Laboratory for Environmental Pollution Prediction and Control of Gansu ProvinceCollege of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China school of Physical science and Technology Lanzhou UniversityLanzhou 730000China

Owing to excellent light absorption and high activity fo r oxygen evolution,monoclinic bismuth vanadate(BiVO_(4)) is regarded as an ideal candidate for photocatalytic water ***,its application is limited by the large particle size in micrometer scale,as well as the slightly positive conduction *** this work,we successfully synthesized nano-BiVO_(4) with particle size ranged from 27 nm to 57 nm by wet chemical method based on electrostatic spinning *** bulk BiVO_(4),the nano-sized BiVO_(4) possesses the ability to generate hydrogen by water splitting,and the activity could reach up to1.66 μmol h^(-1) g^(-1) with the assistance of *** enhanced activity is mainly attributed to the improvements resulted from reduced particle size,which includes elevated conduction band,enlarged specific surface area and promoted charge *** work provides a simple method for synthesizing photocatalyst with small particle size and high yield.

关键词： Nano-sized bismuth vanadate Electrospinning process Charge carrier separation Elevated conduction band Water splitting

Evaluation of the sMOs and sMAP soil moisture products under different vegetation types against two sparse in situ networks over arid mountainous watersheds, Northwest china

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science china Earth sciences 2019年第4期62卷 703-718页

作者： Lanhui ZHANG Chansheng HE Mingmin ZHANG Yi ZHU key laboratory of West china’s environmental system (Ministry of Education) College of Earth and Environmental Sciences Lanzhou University Department of Geography Western Michigan University

Assessment of the suitability of satellite soil moisture products at large scales is urgently needed for numerous climatic and hydrological researches, particularly in arid mountainous watersheds where soil moisture plays a key role in landatmosphere exchanges. This study presents evaluation of the sMOs(L2) and sMAP(L2_P_E and L2_P) products against ground-based observations from the Upstream of the Heihe River Watershed in situ soil Moisture Network(UHRWsMN) and the Ecological and Hydrological Wireless sensor Network(EHWsN) over arid high mountainous watersheds, Northwest *** show that all the three products are reliable in catching the temporal trend of the in situ observations at both point and watershed scales in the study area. Due to the uncertainty in brightness temperature and the underestimation of effective temperature, the sMOs L2 product and both the sMAP L2 products show "dry bias" in the high, cold mountainous area. Because of the more accurate brightness temperature observations viewing at a constant angle and more suitable estimations of single scattering albedo and optical depth, both the sMAP L2 products performed significantly better than the sMOs ***, comparing with station density of in situ network, station representation is much more important in the evaluation of the satellite soil moisture products. Based on our analysis, we propose the following suggestions for improvement of the sMOs and sMAP product suitability in the mountainous areas: further optimization of effective temperature; revision of the retrieval algorithm of the sMOs mission to reduce the topographic impacts; and, careful selection of in situ observation stations for better representation of in situ network in future evaluations. All these improvements would lead to better applicability of the sMOs and sMAP products for soil moisture estimation to the high elevation and topographically complex mountainous areas in arid regions.

关键词： sMOs sMAP Evaluation Different vegetation types sparse in situ networks Arid mountainous watershed

Changes in climate regimes over china based on a high-resolution dataset

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science Bulletin 2019年第6期64卷 377-379页

作者： Wei Huang Jingjing Yan Chang Liu Tingting Xie key laboratory of western china’s environmental systems (Ministry of Education) College of Earth and Environmental Sciences Lanzhou University Central Asia Center for Atmospheric science Research China Meteorological Administration Department of Geosciences University of Arkansas

During the 20th century the global climate has been shifted towards warmer and drier regimes, mainly due to anthropogenic warming [1,2]. Climate changes can notably disrupt the environment and ecosystems. To evaluate the impacts of climate change on ecoregions, the Kdppen-Trewartha (K-T) climate classification [3] is widely used because it was constructed on the basis of surface vegetation. The K-T classification system combines temperature, precipitation, and their seasonality into a single metric. six major climate types and several sub-climate types are defined (A: tropical, B: dry, C: subtropical, D: temperate, E: subpolar, F: polar). Each K-T climate type is consistent with certain prevalent plant species. Definitions and criteria of K-T climate types were outlined by Feng et al.[4].

关键词： climate has been shifted change on ecoregions climate types

Instability characteristics of the East Asian Monsoon recorded by high-resolution loess sections from the last interglacial (MIs5)

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science china Earth sciences 2007年第7期50卷 1067-1075页

作者： GUAN QingYu PAN BaoTian GAO Hongshan LI BingYuan WANG JunPing sU Huai key laboratory of western china’s environmental systems(MOE) Lanzhou UniversityLanzhou 730000China Institute of Geographical sciences and Natural Resources Chinese Academy of SciencesBeijing 100101China

The selection of high-resolution loess sections is needed in order to determine the climatic variability of the East Asian Monsoon during the last interglacial. Two sequences of s1 on the eastern and west-ern sides of the Liupan Mountain were both composed of five paleosol layers and four loess layers,indicating that there were five strong summer monsoon events and four strong winter monsoon events in MIs5. This corresponds with other records of the East Asian Monsoon,along with NGRIP and the North Atlantic records,implying that the climate of the Northern Hemisphere was very instable during the last interglacial. Two layers of paleosols and one layer of loess had developed during MIs5a and MIs5c. Compared with MIs5e,the climate in MIs5a and MIs5c fluctuated more intensively on a millen-nial scale,whereas the climate was relatively stable in MIs5e.

关键词： last interglacial paleosol East Asian monsoon shagou loess section Wangguan loess section Liupan Mountain

A singular spectrum analysis on Holocene climatic oscillation from lake sedimentary record in Minqin Basin, china

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Chinese Journal of Oceanology and Limnology 2007年第2期25卷 149-156页

作者：靳立亚陈发虎丁小俊朱艳 key laboratory of western china's environmental systems The Ministry of Education China Center for Arid Environment and Paleoclimate Research Lanzhou University

The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern china, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the sanjiaocheng (sJC), Triangle Town in Chinese, section (103°20′25″E, 39°00′38″N), which is located at the northwestern boundary of the present Asian summer monsoon in china, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (ssA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7–6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth’s climate systems.

关键词： Quaternary Holocene lake sediment climatic change oscillation analysis singular spectrum analysis proxy record

Formation of present desert landscape surrounding Jilantai salt Lake in northern china based on OsL dating

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Frontiers of Earth science 2015年第3期9卷 497-508页

作者： Yuxin FAN Xiaolong CHEN Wenhao LIU Fu ZHANG Fan ZHANG school of Earth sciences and key laboratory of Mineral Resources in western china of Gansu Province Lanzhou University Lanzhou 730000 China MOE key laboratory of western china's environmental systems Collaborative Innovation Center for Arid Environments and Climate Change Lanzhou University Lanzhou 730000 China

The Jilantai salt Lake （JsL）, a lake of importance due to its salt production in china since the early Qing dynasty, is surrounded by sand dunes. Exploration of the development of these sand dunes will be helpful for identifying the forces underlying the desert landscape and for identifying a solution to protect the salt resources. Through field investigation, we found sand dunes overlying either lacustrine and bog deposits on the lake bed at a lower altitude or littoral sediments on the higher lakeshores. Optically stimulated Luminescence （OsL） dating results indicate that sands started to accumulate around the JsL as early as the early Holocene （around 11 ka）, while the rapid development of sand dunes occurred within the latest 0.1 ka. By comparison with climatic documents and human activities in adjacent regions, the initiation of sand accumulation around the JsL as early as the early Holocene is considered to be the result of low effective moisture in the Jilantai area. However, the rapid development of the sand dunes in the vast area surrounding the JsL was likely initiated by the intensified human activities which occurred within the latest 0.1 ka under warm and dry climatic conditions.

关键词： aeolian sand accumulation Jilantai salt Lake,OsL dating

Apatite Fission Track Constraints on the Pattern of Faulting in the North Qilian Mountain

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Journal of Earth science 2013年第4期24卷 569-578页

作者：李清洋潘保田胡小飞胡振波李富强杨顺智 key laboratory of western china's environmental systems (Ministry of Education) Research School of AridEnvironment & Climate Change Lanzhou University sulige Gasfield Development Company PCOC

The Qilian （祁连） Mountain is an active orogenic belt located at the northeastern margin of the Tibetan Plateau. During the process of continuous convergence between Indian and Eurasian plates, the Qilian Mountain grow correspondingly by means of reaction of old faults and generation of new ones. Here we present apatite fission-track data along a river profile crossing three minor fault （the Minle （民乐）-Damaying （大马营） fault, the Huangcheng （皇城）-Taerzhuang （塔尔庄） fault and the Kangningqiao （唐宁桥） fault） which compose the North Qilian fault （NQF） to test the timing and pat- terns of the fault activities. Apatite fission-track （AFT） results indicate that these minor faults expe- rienced two active phases in the Cretaceous and the Oligocene-Miocene. Further research indicate that the initiation timing of faulting became younger northward in both active periods and the later phase probably more active than the former phase. These tectonic activities might be highly related to the docking of the Lhasa Block to the south in the Cretaceous and uplift and expansion of the Tibetan Pla- teau in the Cenozoic.

关键词： North Qilian Mountain AFT fault activity.