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Non-growing season soil CO_2 efflux and its changes in an alpine meadow ecosystem of the qilian mountains,Northwest China

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Journal of Arid Land 2013年第4期5卷 488-499页

作者： ZongQiang CHANG XiaoQing LIU Qi FENG ZongXi CHE HaiYang XI YongHong SU JianHua SI Alashan Desert Eco-hydrology Experimental Research Station Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences gansu Hydrology and water resources Engineering Center academy of water Resource conservation forests in qilian mountains of gansu province

Most soil respiration measurements are conducted during the growing *** tundra and boreal forest ecosystems,cumulative,non-growing season soil CO2 fluxes are reported to be a significant component of these systems＇ annual carbon ***,little information exists on soil CO2 efflux during the non-growing season from alpine ***,comparing measurements of soil respiration taken annually versus during the growing season will improve the accuracy of estimating ecosystem carbon budgets,as well as predicting the response of soil CO2 efflux to climate *** this study,we measured soil CO2 efflux and its spatial and temporal changes for different altitudes during the non-growing season in an alpine meadow located in the qilian mountains,Northwest *** experiments on the soil CO2 efflux of alpine meadow from the qilian mountains were conducted along an elevation gradient from October 2010 to April *** measured the soil CO2 efflux,and analyzed the effects of soil water content and soil temperature on this *** results show that soil CO2 efflux gradually decreased along the elevation gradient during the non-growing *** daily variation of soil CO2 efflux appeared as a single-peak *** soil CO2 efflux was low at night,with the lowest value occurring between 02：00-06：***,values started to rise rapidly between 07：00-08：30,and then descend again between 16：00-18：*** peak soil CO2 efflux appeared from 11：00 to 16：*** soil CO2 efflux values gradually decreased from October to February of the next year and started to increase in ***-growing season Q10 （the multiplier to the respiration rate for a 10℃ increase in temperature） was increased with raising altitude and average Q10 of the qilian mountains was generally higher than the average growing season Q10 of the Heihe River ***,non-growing season soil CO2 efflux was relatively high in October and early spring and low in the *** soil CO2

关键词： non-growing season soil CO2 efflux spatial and temporal variation alpine meadow Q10 values qilian mountains

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Temporal changes in seasonal precipitation over the Sahara Desert from 1979 to 2016

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Research in Cold and Arid Regions 2021年第3期13卷 220-233页

作者： Sindikubwabo Celestin Feng Qi RuoLin Li WenJu Cheng Jian Ma Habiyakare Telesphore Nzabarinda Vincent Key Laboratory of Eco-hydrology of Inland River Basin Northwest Institute of Eco-Environment and ResourcesChinese Academy of Sciences(CAS)LanzhouGansu 730000China University of Chinese academy of Sciences Beijing 100049China qilian mountains Eco environment Research Center LanzhouGansu 730000China academy of water resources conservation forests in qilian mountains ZhangyeGansu 734000China

Rainfall variability dominates livelihoods in all countries of Saharan *** better understand the processes involved in Sahara precipitation changes,we used the Global Precipitation Climatology Center(GPCC)dataset to examine dry and wet seasonal trends in the Sahara region from 1979 to *** also used the European Centre for Medium-Range Weather Forecasts(ECMWF)to evaluate the general atmospheric circulation associated with seasonal change of Sahara *** Mann-Kendall test and Theil sens'slope estimator methods were adopted to test and estimate the significance and weight of precipitation trend,*** results revealed that Sahara precipitation has increased *** seasonal evaluation shows a positive trend of 0.42 mm/decade and 1.43 mm/decade in JAS(June,August,and September)seasons for the northern and southern Saharan Desert,***,the JFMA(January,February,March,and April)period shows a negative trend but not statistically *** examination of the general circulation and moisture transport changes suggested an increase of rainfall in southern *** wet period is also driven by northward penetration of moisture originating from the Sahel region,African Easterly Jet(AEJ),and weakening in the upper tropospheric zonal *** rainfall has also been likely associated with positive anomalies of sea surface temperature(SST)in the North Tropical Atlantic(NTA)and the Mediterranean Sea.

关键词： Sahara precipitation variability arid Africa climate

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Dune dynamics in the southern edge of Dunhuang Oasis and implications for the oasis protection

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Journal of Mountain Science 2018年第10期15卷 2172-2181页

作者： AN Zhi-shan ZHANG Ke-cun TAN Li-hai ZHANG Hu NIU Bai-cheng Dunhuang Gobi and Desert Research Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Key Laboratory of Desert and Desertification Chinese Academy of SciencesLanzhou 730000China academy of water Resource conservation forests of qilian mountains in gansu province Test Station of Deserification Control in HongshawoZhangye 734000China

The survival of Dunhuang Oasis is largely determined by the evolution of sand dunes in the southern edge of the oasis, mainly composed of shield dunes and mega pyramid dunes, which occupy twothirds and one-third of the area, respectively. However, few studies have focused on dynamics of these dunes, especially in terms of quantification. So the theoretical basis of sand-control engineering is relatively limited. Here we present the characteristics of dune dynamics of a shield dune and mega pyramid dune in the southern edge of Dunhuang Oasis during April 2014-April 2016 based on measurement data of a 3-D laser scanner. Results indicate that the volume of the shield dune decreased during the monitoring period of two years, and the gravity centers of the monitored shield dune moved windward, indicating that sand was transported toward the oasis. Conversely, the dune volume of the mega pyramid dune increased and the gravity center presented no prominent movement, indicating that the megapyramid dune was relatively stable and its migration toward the oasis was not notable. Thus, compared with mega pyramid dunes, shield dunes in the southern edge of Dunhuang Oasis are identified as a more significant sand source endangering the protection of the oasis, and sand-control engineering should mainly focus on these shield dunes.

关键词： Dunhuang Oasis Dune dynamics 3-D laser scanner Shield dune Mega pyramid dune

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Relationship between sand-dust weather and water dynamics of desert areas in the middle reaches of Heihe River

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Research in Cold and Arid Regions 2016年第6期8卷 516-523页

作者： Yun Niu XianDe Liu Xin Li YanQiang Wei Hu Zhang XiaoYan Li Northwest Institute of Eco-Environment and resources Chinese Academy of Sciences Lanzhou Gansu 730000 China academy of Ecology Science of Zhangye Gansu Science and Technology Innovation Service Platform of Ecology in Qilian Mountains Gansu Province Zhangye Gansu 734000 China academy of water Resource conservation forests of qilian mountains in gansu province Test Station of Desertification Control in Hongshawo Zhangye Gansu 734000 China

Sand-dust weather has become an international social-environmental issue of common concern, and constitutes a serious threat to human lives and economic development. In order to explore the responses of natural desert sand and dust to the dynamics of water in desertification, we extracted long-term monitoring data related to precipitation, soil water, groundwater, and sand-dust weather. These data originated from the test stations for desertification control in desert areas of the middle reaches of the Heihe River. We used an algorithm of characteristic parameters, correlations, and multiple regression analysis to establish a regression model for the duration of sand-dust weather. The response char-acteristics of the natural desert sand and dust and changes of the water inter-annual and annual variance were also examined. Our results showed：（1） From 2006 to 2014 the frequency, duration, and volatility trends of sand-dust weather obviously increased, but the change amplitudes of precipitation, soil water, and groundwater level grew smaller. （2） In the vegetative growth seasons from March to November, the annual variance rates of the soil moisture content in each of four studied layers of soil samples were similar, and the changes in the frequency and duration of sand-dust weather were similar. （3） Our new regression equation for the duration of sand-dust weather passed the R test, F test, and t test. By this regression model we could predict the duration of sand-dust weather with an accuracy of 42.9%. This study can thus provide technological support and reference data for water resource management and re-search regarding sand-dust weather mechanisms.

关键词： sand-dust weather water dynamics regression model middle reaches of the Heihe River

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Biomass of Natural Grassland under Different Enclosure Conditions

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Journal of Landscape Research 2016年第1期8卷 69-72页

作者： WANG Shunli LIU Xiande JIN Ming ZHANG Xuelong ZHAO Weijun WANG Rongxin academy of water resources conservation Forest of qilian mountains of gansu province

Taking natural grassland on the northern slope of the qilian Mountain for example, this paper investigated and compared aboveground and belowground biomass of grassland in multi-year enclosure(20 years), one-year enclosure, control areas(natural grazing areas). The results showed that coverage and height of the enclosure sample plots were significantly higher than that of natural grazing area(P one-year enclosure area(299.07 g/m^2) > multi-year enclosure control area(254.39 g/m^2) > one-year enclosure control area(187.37 g/m^2); belowground biomass: multi-year enclosure(2,906.90 g/m^2) > one-year enclosure area(2,587.26 g/m^2) > multi-year enclosure control area(2,378.93 g/m^2) > one-year enclosure control area(2,029.17 g/m^2); mean aboveground biomass of natural grassland was 263.60 g/m^2, mean belowground biomass 2,225.56 g/m^2; ratio of belowground biomass to aboveground biomass varied between 6.79 and 12.90, distribution of belowground biomass and aboveground biomass in each plot showed significant differences(P qilian mountains.

关键词： Natural grassland Aboveground biomass Belowground biomass Enclosure Grazing Coverage

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Simulation of energy and water balance in Soil-Vegetation-Atmosphere Transfer system in the mountain area of Heihe River Basin at Hexi Corridor of northwest China

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Science China Earth Sciences 2005年第4期48卷 538-548页

作者： KANG Ersi1, CHENG Guodong1, , SONG Kechao1, JIN Bowen1, , LIU Xiande3 2 3 & WANG Jinye3 1. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese academy of Sciences, Lanzhou 730000, China 2. State Key Laboratory of Frozen Soil Engineering, Chinese academy of Sciences, Lanzhou 730000, China 3. academy of water resources conservation Forest of qilian mountains, gansu province, Zhangye 734000, China 1. Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences 730000 Lanzhou China 2. State Key Laboratory of Frozen nSoil Engineering Chinese Academy of Sciences 730000 Lanzhou China 3. academy of water resources conservation Forest of qilian mountains 734000 Gansu Province Zhangye China

In the mountain area of inland Heihe River Basin at Hexi Corridor of northwest China during the vegetation growing season from May to September, the Simultaneous Heat and water (SHAW) model of Soil-Vegetation-Atmosphere Transfer (SVAT) system is applied to simulating and studying energy and water balance of the soil-residue-plant canopy layers in the Picea crassifolia forest and the grassland by the forest at the shaded slope and the grassland at the sun-facing slope. The simulation of energy balance indicates that net radiation of the grass- land at the sun-facing slope is more than that of the Picea crassifolia forest and the grassland by the forest at the shaded slope. The energy outgoing components are the first latent heat and next sensible heat from the grassland both at the shaded slope and the sun-facing slope, but those at the former are less. The energy outgoing components are the first sensible heat and next latent heat from the Picea crassifolia forest. The composition and distribution of energy in the soil-residue-plant canopy layers in the Picea crassifolia forest and the grassland by the forest at the shaded slope make the soil layer receive less energy, which therefore, especially the forest possesses the energy conditions for soil water conservation. The simulation of water balance indicates that the water loss of the grassland at the sun-facing slope is mainly caused by soil evaporation, while evapotranspiration of the Picea crassifolia forest and the grassland by the forest at the shaded slope is less than that of the grassland at the sun-facing slope. Half of the evapotranspiration of the Picea crassifolia forest and the grassland by the forest at the shaded slope is consumed by transpiration. After precipitation, the soil water storage is increased much more for the Picea crassifolia forest and also more for the grassland by the forest at the shaded slope. Therefore the shaded slope vegetation, especially the forest is favorable for soil water s

关键词： inland rivers, mountain vegetation zone, Soil-Vegetation-Atmosphere Transfer (SVAT) system, energyand water balance, simulation.

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Measuring and modeling evapotranspiration of a Populus euphratica forest in northwestern China

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Journal of Forestry Research 2021年第5期32卷 1963-1977页

作者： Guanlong Gao Qi Feng Xiande Liu Yonghua Zhao College of Environment and Resource Shanxi UniversityTaiyuan 030006People’s Republic of China Shaanxi Key Laboratory of Land Consolidation Chang’an UniversityXi’an 710064People’s Republic of China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of SciencesLanzhou 730000People’s Republic of China academy of water resources conservation forests in qilian mountains of gansu province Zhangye 734000People’s Republic of China

Vegetation is sparsely distributed in the arid regions of northwestern China,and accurately measuring and partitioning of evapotranspiration is of importance for ecosystems in such *** this study,we measured and analyzed diurnal and phenological variations in evapotranspiration using the eddy-covariance method based on the Penman-Monteith,Priestley-Taylor,Shuttleworth-Wallace models,a newly proposed improved dual source model and a clumped model in a forest reserve in the Ejin oasis of Populus euphratica in 2015 and 2016 growing seasons.A sensitivity analysis was performed for the models with higher accuracies and we examined the biotic and abiotic controls on *** results show that the total amounts of evapotranspiration during the two growing seasons in 2015 and 2016 were 622 and 612 mm,*** variations in evapotranspiration produced single-peak curves,while diurnal variations reflected the influence of high temperatures on some *** Priestley-Taylor and the improved dual source models gave the most accurate evapotranspiration values at the daily scale and appeared to be most suitable for the estimation of evapotranspiration for the species in arid *** addition,both models were the most sensitive to net radiation(Rn).

关键词： Evapotranspiration Eddy-covariance Populus euphratica Northwestern China

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Assessing artificial neural networks coupled with waveletanalysis for multi-layer soil moisture dynamics pr

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Research in Cold and Arid Regions 2016年第2期8卷 116-124页

作者： Yang Junjun He Zhibin Zhao Weijun Du Jun Chen Longfei Zhu Xi Linze Inland River Basin Research Station Chinese Ecosystem Research Network Cold and Arid Regions Environmental and Engineering Research Institute Key Laboratory of Eco-hydrology of Inland River Basin Chinese Academy of Sciences Gansu Lanzhou 730000 academy of water resources conservation forests in qilian mountains of gansu province Gansu Zhangye 734000

Soil moisture simulation and prediction in semi-arid regions are important for agricultural production, soil conservation and climate change. However, considerable heterogeneity in the spatial distribution of soil moisture, and poor ability of distributed hydrological models to estimate it, severely impact the use of soil moisture models in research and practical applications. In this study, a newly-developed technique of coupled (WA-ANN) wavelet analysis (WA) and artificial neural network (ANN) was applied for a multi-layer soil moisture simulation in the Pailugou catchment of the qilian mountains, gansu province, China. Datasets included seven meteorological factors: air and land surface temperatures, relative humidity, global radiation, atmospheric pressure, wind speed, precipitation, and soil water content at 20, 40, 60, 80, 120 and 160 cm. To investigate the effectiveness of WA-ANN, ANN was applied by itself to conduct a comparison. Three main findings of this study were: (1) ANN and WA-ANN provided a statistically reliable and robust prediction of soil moisture in both the root zone and deepest soil layer studied (NSE >0.85, NSE means Nash-Sutcliffe Efficiency coefficient); (2) when input meteorological factors were transformed using maximum signal to noise ratio (SNR) and one-dimensional auto de-noising algorithm (heursure) in WA, the coupling technique improved the performance of ANN especially for soil moisture at 160 cm depth; (3) the results of multi-layer soil moisture prediction indicated that there may be different sources of water at different soil layers, and this can be used as an indicator of the maximum impact depth of meteorological factors on the soil water content at this study site. We conclude that our results show that appropriate simulation methodology can provide optimal simulation with a minimum distortion of the raw-time series; the new method used here is applicable to soil sciences and management applications.

关键词： artificial neural network de-noising wavelet analysis time series analysis soil moisture prediction

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Response of Grassland Biomass to Soil Moisture in the Arid Mountainous Area of the qilian mountains

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Journal of Landscape Research 2018年第1期10卷 77-82页

作者： WANG Shunli WANG Rongxin JING Wenmao ZHAO Weijun NIU Yun MA Jian ZHU Hong academy of water resources conservation Forest of qilian mountains of gansu province Zhangye Gansu 734000 China Northwest Research Institute of Mining and Metallurgy Baiying Gansu 730900 China

The Pailugou watershed of the qilian mountains in the arid region of northeast China was selected for research to analyze the species, height, and biomass in typical mountain grassland with an altitude of 2,700–3,000 m and measure soil moisture, so as to explore the seasonal characteristics of grassland biomass as altitude increases and the relationship between grassland biomass and soil moisture. The results showed that:(1) with a mean value of 135.36 g/m^2, grassland aboveground biomass showed a unimodal distribution from rise to decline as altitude increased, and reached its maximum of 176.79 ± 28.37 g/m^2 at an altitude of 2,900 m; with a mean value of 946.13 g/m^2, grassland underground biomass showed an uptrend as altitude increased, and reached its maximum of 1,301.19 ± 68.24 g/m^2 at an altitude of 3,000 m;(2) the difference between aboveground biomass and underground biomass in the grassland at different altitudes was significant;(3) values of root shoot ratio of the arid mountain grassland varied between 4.14–11.95;(4) values of soil moisture content of the arid mountain grassland varied between 9.23%–31.31%;(5) there was a positive correlation between aboveground biomass and underground biomass and the mean soil moisture content(p < 0.05), with a correlation coefficient of 0.778 4 and 0.784 3 respectively, soil layers with different moisture content made different contributions to grassland biomass, and moisture content in the soil layer where over-60-cm root systems were located was of significance to grassland biomass.

关键词： Mountain grassland Biomass Soil moisture qilian mountains

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Analysis of the Relationship Between Plant Growth and Moisture Variation in the Desert Area of Hexi Corridor

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Journal of Landscape Research 2018年第5期10卷 122-127页

作者： NIU Yun CHENG Caixia School of Urban and Environmental Sciences Huaiyin Normal UniversityHuai’anJiangsu 223300China academy of water Resource conservation forests of qilian mountains in gansu province ZhangyeGansu 734000China

In order to analyze the relationship between desert plant growth and precipitation,soil moisture,as well as groundwater in desertification control,a comprehensive desertification prevention and control station was established in the desert area of Hexi Corridor for long-term location monitoring,and data of precipitation,soil moisture,groundwater,coverage,and biomass were *** including characteristic parameter algorithm,correlation analysis,and stepwise multiple linear regression analysis were employed to analyze the annual and inter-annual variation characteristics of plant growth and moisture,and related regression models were *** results showed that:(1) from 2006 to 2014,the inter-annual variation of soil moisture was the most drastic,the precipitation,biomass,and coverage underwent a similarly great variation,and the variation of the groundwater was the most *** coverage showed a significantly fluctuating uptrend,and the biomass increased *** precipitation,soil moisture,and groundwater showed a slight decrease,but it was not obvious.(2) During the plant growing season from March to November,the change of moisture content in each layer of soil was basical y the same,and the changes in biomass and coverage were basically the same,so were the changes in precipitation and *** order of the change range from large to small within the year was precipitation > groundwater depth > biomass > average coverage > soil moisture content.(3) Both the coverage and biomass models passed the R-fitting test,the F-test,and the *** models predicted the variation of 58.0% and 98.7%,and the accuracy rate reached 52.0% and 86.2%.The research results can provide scientific support and reference data for water resources management in the prevention and control of desertification,as well as the evaluation of the influence of projects such as returning farmland to forest,natural forest protection,and comprehensive management of the H

关键词： Biomass Coverage Precipitation Soil moisture Groundwater Hexi Corridor

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