Spatial and temporal variation of precipitation characteristics in the semiarid region of Xi'an, northwest China

Abstract Precipitation variations mostly affect the water resource planning in semi-arid regions of northwest China. The objective of this study is to quantitatively explore the spatial and temporal variations of precipitation in different time scales in Xi'an city area. The Mann–Kendall test and wavelet analysis methods were applied to analyze the precipitation variability. In terms of temporal variation of precipitation, the results indicated that the annual precipitation exhibited a significant decreasing trend during 1951–2018. Except for summer precipitation representing a slightly increasing trend, the other seasonal precipitations had a similar decreasing trend to annual precipitation throughout 1951–2018. The monthly precipitation had different change trends, showing the precipitation from June to September could account for 58.4% of the total annual precipitation. In addition, it was clear that annual precipitation had a significant periodic change, with the periods of 6, 13, 19, and 27 years. For the spatial variation of precipitation during 1961–2018, the results showed that annual and seasonal precipitation exhibited obvious spatial differences, indicating an increasing spatial trend from north to south. Thus, understanding the precipitation variation in Xi'an city can provide a theoretical foundation of future water resources management for other cities in semi-arid regions of northwest China.

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Reducing human activity promotes environmental restoration in arid and semi-arid regions: A case study in Northwest China

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.144525 ◽

2021 ◽

pp. 144525

Author(s):

Chuanhua Li ◽

Yutao Wang ◽

Xiaodong Wu ◽

Hongjuan Cao ◽

Wangping Li ◽

...

Keyword(s):

Human Activity ◽

Arid Regions ◽

Northwest China ◽

Environmental Restoration ◽

Semi Arid

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Spatial–Temporal Evolution Characteristics and Influencing Factors of Agricultural Water Use Efficiency in Northwest China—Based on a Super-DEA Model and a Spatial Panel Econometric Model

Water ◽

10.3390/w13050632 ◽

2021 ◽

Vol 13 (5) ◽

pp. 632

Author(s):

Weinan Lu ◽

Wenxin Liu ◽

Mengyang Hou ◽

Yuanjie Deng ◽

Yue Deng ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Water Resource ◽

Arid Regions ◽

Econometric Model ◽

Northwest China ◽

Agricultural Water ◽

Agricultural Water Use ◽

Use Efficiency ◽

Semi Arid

Improving agricultural water use efficiency (AWUE) is an important way to solve the shortage of water resources in arid and semi-arid regions. This study used the Super-DEA (data envelopment analysis) to measure the AWUE of 52 cities in Northwest China from 2000 to 2018. Based on spatial and temporal perspectives, it applied Exploratory Spatial Data Analysis (ESDA) to explore the dynamic evolution and regional differences of AWUE. A spatial econometric model was then used to analyze the main factors that influence the AWUE in Northwest China. The results showed firstly that the overall AWUE in Northwest China from 2000 to 2018 presented a steady upward trend. However, only a few cities achieved effective agricultural water usage by 2018, and the differences among cities were obvious. Secondly, AWUE showed an obvious spatial autocorrelation in Northwest China and showed significant high–high and low–low agglomeration characteristics. Thirdly, economic growth, urbanization development, and effective irrigation have significant, positive effects on AWUE, while per capita water resource has a significant, negative influence. Finally, when improving the AWUE in arid and semi-arid regions, plans should be formulated according to local conditions. The results of this study can provide new ideas on the study of AWUE in arid and semi-arid regions and provide references for the formulation of regional agricultural water resource utilization policies as well.

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Spatial distribution and temporal variation of microcrustaceans assembly (Cladocera and Copepoda) in different compartments of a reservoir in the brazilian semiarid region

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x9616 ◽

2018 ◽

Vol 30 (0) ◽

Cited By ~ 1

Author(s):

Josiane Souza Santos ◽

Nadson Ressyé Simões ◽

Sérgio Luiz Sonoda

Keyword(s):

Spatial Distribution ◽

Spatial Variation ◽

Temporal Variation ◽

Aquatic Macrophytes ◽

Temporal Dynamics ◽

Lateral Compartment ◽

Spatial And Temporal Variation ◽

Semiarid Region ◽

Brazilian Semiarid ◽

Significant Spatial Variation

Abstract Aim: The objective of this study was to investigate the spatial and temporal variation of microcrustacean assemblages of a reservoir in the Brazilian semiarid region. Methods Physical and chemical water variables and samples of microcrustaceans were collected at eight sites of the reservoir between July 2013 and November 2014, in a total of seven campaigns. For this study, the reservoir was categorized in two compartments: lateral and central. Results Limnological variables showed significant temporal variation (PERMANOVA, Pseudo-F = 19.51, p = 0.001). Higher turbidity values and suspended solids were observed in the rainiest months, while during the dry months, we measured higher values of transparency, dissolved oxygen, and chlorophyll-a. It was not found significant spatial variation of limnological variables (PERMANOVA, Pseudo-F = 0.96; p = 0.394). During the study period, ten species were recorded: four Cladocera (Ceriodaphnia cornuta, Daphnia gessneri, Diaphanosoma birgei and Diaphanosoma spinulosum ) three Copepoda Calanoida (Argyrodiaptomus azevedoi, Notodiaptomus cearensis and Notodiaptomus iheringi) and three Copepoda Cyclopoida (Macrocyclops albidus, Thermocyclops minutus and Thermocyclops decipiens). The microcrustacean assemblages showed significant temporal variation (PERMANOVA, Pseudo-F = 4.34; p = 0.001) as well as significant spatial variation (PERMANOVA, Pseudo-F = 9.46; p = 0.001). The highest values of abundance and richness were observed in the lateral compartment, this result is mainly related to the presence of aquatic macrophytes in this region, because the analysis of partial RDA indicated that limnological variables explained only 11% of this variation (Pseudo-F = 2.08, p = 0.001). Conclusions The results suggest that the seasonality of the semiarid is an important factor in the temporal dynamics of the limnological variables, while the aquatic macrophytes play an important role in the spatial distribution of the microcrustacean assembly.

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Spatio-temporal Variation of Soil Respiration and Its Driving Factors in Semi-arid Regions of North China

Chinese Geographical Science ◽

10.1007/s11769-017-0899-1 ◽

2018 ◽

Vol 28 (1) ◽

pp. 12-24 ◽

Cited By ~ 3

Author(s):

Xinhua Zeng ◽

Yigang Song ◽

Wanjun Zhang ◽

Shengbing He

Keyword(s):

Soil Respiration ◽

Temporal Variation ◽

Arid Regions ◽

North China ◽

Driving Factors ◽

Spatio Temporal ◽

Semi Arid

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Spatial distribution and temporal variation of reference evapotranspiration in arid and semi-arid regions of Iran

Hydrological Processes ◽

10.1002/hyp.8146 ◽

2011 ◽

Vol 26 (4) ◽

pp. 500-512 ◽

Cited By ~ 57

Author(s):

Hossein Tabari ◽

Ali Aeini ◽

P. Hosseinzadeh Talaee ◽

B. Shifteh Some'e

Keyword(s):

Spatial Distribution ◽

Temporal Variation ◽

Arid Regions ◽

Reference Evapotranspiration ◽

Semi Arid

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Is Annual Recharge Coefficient a Valid Concept in Arid and Semi-Arid Region?

10.5194/hess-2017-160 ◽

2017 ◽

Cited By ~ 1

Author(s):

Yiben Cheng ◽

Hongbin Zhan ◽

Wenbin Yang ◽

Hongzhong Dang ◽

Wei Li

Keyword(s):

Arid Regions ◽

Groundwater Resources ◽

Heavy Precipitation ◽

Annual Precipitation ◽

Precipitation Event ◽

Precipitation Pattern ◽

Deep Soil ◽

Bare Sand ◽

Sand Land ◽

Semi Arid

Abstract. Deep soil recharge (DSR) (at depth more than 200 cm) is an important part of water circulation in arid and semi-arid regions. Quantitative monitoring of DSR is of great importance to assess water resources and study water balance in arid and semi-arid regions. Simple estimates of recharge based on fixed fractions of annual precipitation are misleading because they do not reflect the plant and soil factors controlling recharge. This study used a typical bare land on the Eastern margin of Mu Us Sandy Land of China an example to illustrate a new lysimeter method of measuring DSR underneath bare sand land in arid and semi-arid regions. Positioning monitoring was done on precipitation and DSR measurement underneath mobile sand dunes from 2013 to 2015 in the study area. Results showed that use of a constant recharge coefficient for estimating DSR in bare sand land in arid and semi-arid regions is questionable and could lead to considerable errors. It appeared that DSR in those regions was influenced by precipitation pattern, and was closely correlated with spontaneous heavy precipitation (defined for an event with more than 10 mm precipitation) other than the average precipitation strength. This study showed that as much as 42 % of precipitation in a single heavy precipitation event can be transformed into DSR. During the observation period, the maximum annual DSR could make up to 24.33 % of the annual precipitation. This study provided a reliable method of estimating DSR in sandy area of arid and semi-arid regions, which is valuable for managing groundwater resources and ecological restoration in those regions.

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Spatial and temporal variation of the near-surface wind regimes in the Taklimakan Desert, Northwest China

Theoretical and Applied Climatology ◽

10.1007/s00704-019-02824-w ◽

2019 ◽

Vol 138 (1-2) ◽

pp. 433-447 ◽

Cited By ~ 1

Author(s):

Zhengyao Liu ◽

Zhibao Dong ◽

Zhengcai Zhang ◽

Xujia Cui ◽

Nan Xiao

Keyword(s):

Temporal Variation ◽

Surface Wind ◽

Northwest China ◽

Spatial And Temporal Variation ◽

Taklimakan Desert ◽

Near Surface ◽

The Taklimakan Desert ◽

Wind Regimes

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Study on the hydro-chemistry process after mixing between water and rocks

Water Quality Research Journal ◽

10.2166/wcc.2018.284 ◽

2018 ◽

Vol 54 (2) ◽

pp. 104-114

Author(s):

Xiuyan Jing ◽

Hongbin Yang ◽

Na Wang

Keyword(s):

River Water ◽

Arid Regions ◽

Yellow River ◽

Dilution Effect ◽

Northwest China ◽

Experimental Simulation ◽

The Yellow River ◽

Mixing Ratio ◽

Close Attention ◽

Semi Arid

Abstract The chemical evolution of groundwater has received close attention from hydro-geologists. Northwest China largely consists of arid and semi-arid regions, where surface water and groundwater frequently exchange with each other, and where the mixing and water–rock interactions significantly affect the direction of water quality evolution. Based on experimental simulation, this paper investigates the interactions among the Yellow River water, groundwater and rocks in Yinchuan. The study found that when groundwater is mixed with the Yellow River water, the Yellow River water has a certain dilution effect on the hydro-chemical composition of groundwater; however, this effect is not simply diluted by proportion for no reaction between irons, but a portion of calcium, sulfur, and carbonate form precipitates. After mixing of the Yellow River water, groundwater and rocks, the pH increased, and the carbon dioxide system reached equilibrium again. In addition, CO32− was produced. While Na+ increase was mainly due to dissolution, SO42− decrease was because of precipitation. The precipitation or dissolution of Ca2+, Mg2+, and CO32− mainly depended on the mixing ratio between groundwater and river water, which suggested the reversible behavior of the dissolution-precipitation of carbonate minerals.

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