scholarly journals Analysis of Changes in Precipitation and Drought in Aksu River Basin, Northwest China

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Yuhu Zhang ◽  
Wanyuan Cai ◽  
Qiuhua Chen ◽  
Yunjun Yao ◽  
Kaili Liu
Keyword(s):  
Meteorological Data ◽  
Standardized Precipitation Index ◽  
Northwest China ◽  
Precipitation Series ◽  
Significance Level ◽  
Spatiotemporal Trends ◽  
Increasing Trend ◽  
Almost All ◽  
Increasing Trends ◽  
Aksu River Basin

The analysis of the spatiotemporal trends of precipitation and drought is relevant for the future development and sustainable management of water resources in a given region. In this study, precipitation and Standardized Precipitation Index (SPI) trends were analyzed through applying linear regression, Mann–Kendall, and Spearman’s Rho tests at the 5% significance level. For this goal, meteorological data from 9 meteorological stations in and around Aksu Basin during the period 1960–2010 was used, and two main annual drought periods were detected (1978-1979 and 1983–1986), while the extremely dry years were recorded in 1975 and 1985 at almost all of the stations. The monthly analysis of precipitation series indicates that all stations had increasing trend in July, October, and December, while both increasing and decreasing trends were found in other months. For the seasonal scale, precipitation series had increasing trends in summer and winter. 33% of the stations had the decreasing trend on precipitation in the spring series, and it was 11% in the autumn. At the same time, the SPI-12 values of all stations had the increasing trend. The significant trends were detected at Aheqi, Baicheng, Keping, and Kuche stations.

scholarly journals Impact of climate change and human activity on the runoff in the upper reaches of the Shiyang River, Northwest China

2014 ◽  
Author(s):  
Peng Li ◽  
Jianhua Xu ◽  
Zhongsheng Chen ◽  
Benfu Zhao
Keyword(s):  
Climate Change ◽  
Human Activity ◽  
Climatic Factors ◽  
Meteorological Data ◽  
Northwest China ◽  
Potential Evaporation ◽  
The Past ◽  
Shiyang River Basin ◽  
Runoff Change ◽  
Increasing Trend

Based on the hydrological and meteorological data of the upper reaches of Shiyang River basin in Northwest China from 1960 to 2009, this paper analyzed the change in runoff and its related climatic factors, and estimated the contribution of climate change and human activity to runoff change by using the moving T test, cumulative analysis of anomalies and multiple regression analysis. The results showed that temperature revealed a significant increasing trend, and potential evaporation capacity decreased significantly, while precipitation increased insignificantly in the past recent 50 years. Although there were three mutations in 1975, 1990 and 2002 respectively, runoff presented a slight decreasing trend in the whole period. The contributions of climate change and human activity to runoff change during the period of 1976-2009 were 45% and 55% respectively.

scholarly journals A Multilayer Soil Moisture Dataset Based on the Gravimetric Method in China and Its Characteristics

2019 ◽  
Vol 20 (8) ◽  
pp. 1721-1736 ◽  
Author(s):  
Aihui Wang ◽  
Xueli Shi
Keyword(s):  
Soil Moisture ◽  
Soil Depth ◽  
Linear Trend ◽  
Standardized Precipitation Index ◽  
Gravimetric Method ◽  
Northwest China ◽  
Soil Layers ◽  
Significance Level ◽  
The Mean ◽  
The Standardized Precipitation Index

Abstract Based on the gravimetric-technique-measured soil relative wetness and the observed soil characteristic parameters from 1992 to 2013 in China, this study derives a user-convenient monthly volumetric soil moisture (SM) dataset from 732 stations for five soil layers (10, 20, 50, 70, and 100 cm). The temporal–spatial variations in SM and its relationship with precipitation (Pr) in different subregions are then explored. The magnitude of SM is relatively large in south China and is low in northwest China, and it generally increases with soil depth in each region. The maximum SM appears in spring and/or autumn and the minimum in summer, and the SM seasonality does not vary as distinctly as that of Pr. For the top three soil layers (10-, 20-, and 50-cm levels), the linear trend analysis indicates an overall increasing SM tendency, and the mean trends (averaged across stations with trends passing a 95% significance level test) are 9.35 × 10−7, 7.37 × 10−3, and 2.45 × 10−3 cm3 cm−3 yr−1, respectively. SM memory depends on the soil depth and regions, and it has longer retention time in the deeper layers. Furthermore, the correlation between SM and antecedent Pr varies with soil depth and lag time. The antecedent Pr anomaly (1 or 2 months in advance) can be used to some extent as a surrogate SM anomaly in most regions except for in arid regions. This result is further demonstrated by the relationships between the SM anomaly and the standardized precipitation index. The current SM dataset can be used in various applications, such as validating satellite-retrieved products and model outputs.

Variations and Sensitivity Analysis of Reference Evapotranspiration During 2010-2019 in the Zhangye Farmland Oasis, Northwest China

2021 ◽  
Author(s):  
Miao Fang
Keyword(s):  
Sensitivity Analysis ◽  
Reference Evapotranspiration ◽  
Sunshine Duration ◽  
Northwest China ◽  
Meteorological Factor ◽  
Maximum Temperature ◽  
Regression Equations ◽  
Significance Level ◽  
Hargreaves Equation ◽  
Increasing Trends

Abstract Reference evapotranspiration (ET0) is an important parameter for agricultural water management in the arid Zhangye farmland oasis. However, the ET0 variations in this oasis over the last decade and meteorological forcings of these variations are unknown. This study investigated the ET0 variations during 2010-2019 in this oasis using the FAO-56 Penman-Monteith (PM) and Hargreaves equations. Results showed that the ET0 features daily and monthly variations with peak values in mid-July and an annual cycle. Although the estimated ET0 series based on the two equations have high correlations in the time domain, the Hargreaves equation always underestimates the ET0 compared to the PM equation. The yearly ET0 showed statistically significant increasing trends (90% significance level) during 2010-2019, while statistically significant increasing trends in monthly ET0 are found only in March and November. Increasing trends reflected in monthly and yearly ET0 are mainly attributed to the increasing maximum temperature and sunshine duration and decreasing relative humidity. Sensitivity analysis demonstrated that the meteorological factor to which the ET0 is most sensitive varies with time scale and equation. Moreover, regression equations used to correct the underestimation associated with the Hargreaves equation for estimating ET0 in the Zhangye farmland oasis also were constructed.

scholarly journals Evaluation of water productivity under climate change in irrigated areas of the arid Northwest China using an assemble statistical downscaling method and an agro-hydrological model

2018 ◽  
Vol 379 ◽  
pp. 393-402
Author(s):  
Liu Liu ◽  
Zezhong Guo ◽  
Guanhua Huang
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Statistical Downscaling ◽  
Arid Region ◽  
Meteorological Data ◽  
Water Productivity ◽  
Northwest China ◽  
Heihe River ◽  
Climate Change Scenarios ◽  
Increasing Trend

Abstract. The Heihe River Basin (HRB) is the second largest inland river basin, located in the arid region of Northwest China with a serious water shortage. Evaluation of water productivity will provide scientific implications for agricultural water-saving in irrigated areas of the arid region under climate change. Based on observed meteorological data, 23 GCMs outputs and the ERA-40 reanalysis data, an assemble statistical downscaling model was developed to generate climate change scenarios under RCP2.6, RCP4.5, RCP8.5 respectively, which were then used to drive the SWAP-EPIC model to simulate crop growth in the irrigated areas of the middle HRB for the future period from 2018 to 2047. Crop yield showed an increasing trend, while crop water consumption decreased gradually in Gaotai and Ganzhou irrigated areas. The water productivity in future 30 years showed an increasing trend in both Gaotai and Ganzhou areas, with the most significant increase under RCP4.5 scenario, which were both larger than 2 kg m−3. Compared with that of the period from 2012 to 2015, the water productivity during 2018–2047 under three RCP scenarios increased by 9.2, 14.3 and 11.8 % in the Gaotai area, and 15.4, 21.6, 19.9 % in the Ganzhou area, respectively.

scholarly journals Trend analysis of temperature and precipitation in Trarza region of Mauritania

2018 ◽  
Vol 10 (3) ◽  
pp. 484-493 ◽  
Author(s):  
Ely Yacoub ◽  
Gokmen Tayfur
Keyword(s):  
Trend Analysis ◽  
Time Series Data ◽  
Series Data ◽  
Trend Test ◽  
Significance Level ◽  
Temperature And Precipitation ◽  
Pettitt Test ◽  
Almost All ◽  
Trend Identification ◽  
Increasing Trends

Abstract Trend analysis of annual temperature and precipitation time series data collected from three stations (Boutilimit (station 1), Nouakchott (station 2) and Rosso (station 3)) has been used to detect the impacts of climate change on water resources in Trarza region, Mauritania. The Mann–Kendall, the Spearman's rho, and the Şen trend test were used for the trend identification. Pettitt's test was used to detect the change point of the series while the Theil–Sen approach was used to estimate the magnitude of the slope in the series. For precipitation, two stations (1 and 3) indicated statistically significant increase in trends. In the case of temperature, almost all the stations show statistically significant increasing trends in the maximum, minimum, and average temperatures. The magnitude of precipitation detected by the Theil–Sen test for stations 1 and 3, respectively, was found to be at the rate of 2.93 and 3.35 mm/year at 5% significance level. The magnitude trend of temperature detected by the Theil–Sen approach was found to be at the rate of 0.2–0.4 °C per decade for almost all the stations. The change points of temperature trends detected by Pettitt test are found to be in the same year (1995) for all the stations.

scholarly journals ATMOSPHERIC DROUGHT IN THE POLISH TATRAS AND THEIRFORELAND IN THE YEARS 1951–2017

2021 ◽  
Vol 20 (1) ◽  
pp. 55-67
Author(s):  
Marta Cebulska ◽  
Keyword(s):  
Atmospheric Circulation ◽  
Standardized Precipitation Index ◽  
Atmospheric Precipitation ◽  
Kendall Test ◽  
Drought Severity ◽  
Monthly Precipitation ◽  
Significance Level ◽  
Circulation Types ◽  
Almost All ◽  
The Impact

Aim of the study. The aim of this study is to assess the variability of the lowest monthly totals of precipitation, and to evaluate the impact of atmospheric circulation on the occurrence of months with a deficit of precipitation. Material and methods. Material: The monthly totals of atmospheric precipitation for the years 1951–2017 from 19 meteorological stations located in the Polish Tatra Mountains and in their foreland. and the calendar of atmospheric circulation types for southern Poland, which was developed by Niedźwiedź (1981; 2018). Methods: Standardized Precipitation Index (SPI), the Mann-Kendall test Results and conclusions. No statistically significant trend at a significance level of 0.05 was noted in the course of the lowest monthly precipitation totals at any of the meteorological stations. In the 67-year period, all the measuring stations saw a total of 499 (3.3%) dry months with varying drought severity. The largest number of extremely dry months occurred in August and April, respectively. In the case of months when the lowest totals of precipitation occurred in the same month at all or almost all of the meteorological stations, three types of anticyclonic circulation dominated, i.e. eastern, south-eastern, southern, and the anticyclonic wedge.

scholarly journals Spatiotemporal Variations of Precipitation in China Using Surface Gauge Observations from 1961 to 2016

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 303 ◽  
Author(s):  
Yunfei Su ◽  
Chuanfeng Zhao ◽  
Yuan Wang ◽  
Zhanshan Ma
Keyword(s):  
North China ◽  
Temporal Trends ◽  
Precipitation Amount ◽  
Northwest China ◽  
Precipitation Trend ◽  
Increasing Trend ◽  
Precipitation Type ◽  
Almost All ◽  
Light Precipitation

Long-term precipitation trend is a good indicator of climate and hydrological change. The data from 635 ground stations are used to quantify the temporal trends of precipitation with different intensity in China from 1961 to 2016. These sites are roughly uniformly distributed in the east or west regions of China, while fewer sites exist in the western region. The result shows that precipitation with a rate of <10 mm/day dominates in China, with a fraction of >70%. With a 95% confidence level, there is no significant temporal change of annually averaged precipitation in the whole of China. Seasonally, there are no significant temporal changes except for a robust decreasing trend in autumn. Spatially, significant differences in the temporal trends of precipitation are found among various regions. The increasing trend is the largest in Northwest China, and the decreasing trend is the largest in North China. The annually averaged number of precipitation days shows a decreasing trend in all regions except for Northwest China. Regarding precipitation type, the number of light precipitation days shows a robust decreasing trend for almost all regions, while other types show no significant change. Considering the high frequency, the temporal trends of light precipitation could highly explain the temporal variation of the total precipitation amount in China.

scholarly journals Impact of climate change and human activity on the runoff in the upper reaches of the Shiyang River, Northwest China

2014 ◽  
Author(s):  
Peng Li ◽  
Jianhua Xu ◽  
Zhongsheng Chen ◽  
Benfu Zhao
Keyword(s):  
Climate Change ◽  
Human Activity ◽  
Climatic Factors ◽  
Meteorological Data ◽  
Northwest China ◽  
Potential Evaporation ◽  
The Past ◽  
Shiyang River Basin ◽  
Runoff Change ◽  
Increasing Trend

Based on the hydrological and meteorological data of the upper reaches of Shiyang River basin in Northwest China from 1960 to 2009, this paper analyzed the change in runoff and its related climatic factors, and estimated the contribution of climate change and human activity to runoff change by using the moving T test, cumulative analysis of anomalies and multiple regression analysis. The results showed that temperature revealed a significant increasing trend, and potential evaporation capacity decreased significantly, while precipitation increased insignificantly in the past recent 50 years. Although there were three mutations in 1975, 1990 and 2002 respectively, runoff presented a slight decreasing trend in the whole period. The contributions of climate change and human activity to runoff change during the period of 1976-2009 were 45% and 55% respectively.

scholarly journals Trend Analysis of Precipitation in the Jinsha River Basin in China

2013 ◽  
Vol 14 (1) ◽  
pp. 290-303 ◽  
Author(s):  
Shunjiu Wang ◽  
Xinli Zhang ◽  
Zhigang Liu ◽  
Deming Wang
Keyword(s):  
River Basin ◽  
Annual Precipitation ◽  
Precipitation Trend ◽  
Precipitation Series ◽  
Jinsha River ◽  
Increasing Trend ◽  
Precipitation Area ◽  
Increasing Trends ◽  
Increasing Precipitation ◽  
Precipitation Trends

Abstract According to the mean seasonal and annual precipitation from 30 meteorological stations in the periods of 1961–2008, the precipitation trends are analyzed by using the Mann–Kendall (MK) test in the Jinsha River basin (JRB). Both the temporal and spatial distribution characteristics of precipitation trends in different regions in the JRB are studied for the first time in this paper. There is a slight and insignificant increasing trend in seasonal and annual precipitation except for autumn precipitation, and the annual precipitation has increased by 0.7634 mm yr−1 during the last 48 years. The increasing precipitation trends in spring seem more significant than those in the other three seasons, and autumn is the only season showing a slight and insignificant decreasing precipitation trend. There are more than 80% of stations exhibiting increasing trends for annual precipitation, and it goes to 90% for spring precipitation. The increasing precipitation trends in the headwater and the middle reaches are more dominant than those in the upper and lower reaches. The largest increase magnitude occurred in the less precipitation area, while the largest decrease magnitude occurred in the more precipitation area. The increasing trend of minimum precipitation series and decreasing trend of maximum precipitation series could result in a decreasing trend for the range series in the JRB. In general, the increasing trends of precipitation in the tributary (the Yalong River) are more significant than those in the mainstream (the Jinsha River). The results of this study will provide further knowledge for understanding on the climate change in the JRB.

Trends in Periprosthetic Knee Infection and Associated Costs: A Population-Based Study Using National Data

2020 ◽  
Author(s):  
Robert Brochin ◽  
Jashvant Poeran ◽  
Khushdeep S. Vig ◽  
Aakash Keswani ◽  
Nicole Zubizarreta ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Length Of Stay ◽  
Knee Arthroplasty ◽  
Trend Test ◽  
Strong Impact ◽  
Hospitalization Costs ◽  
Teaching Status ◽  
Increasing Trend ◽  
Total Knee ◽  
Increasing Trends

AbstractGiven increasing demand for primary knee arthroplasties, revision surgery is also expected to increase, with periprosthetic joint infection (PJI) a main driver of costs. Recent data on national trends is lacking. We aimed to assess trends in PJI in total knee arthroplasty revisions and hospitalization costs. From the National Inpatient Sample (2003–2016), we extracted data on total knee arthroplasty revisions (n = 782,449). We assessed trends in PJI prevalence and (inflation-adjusted) hospitalization costs (total as well as per-day costs) for all revisions and stratified by hospital teaching status (rural/urban by teaching status), hospital bed size (≤299, 300–499, and ≥500 beds), and hospital region (Northeast, Midwest, South, and West). The Cochran–Armitage trend test (PJI prevalence) and linear regression determined significance of trends. PJI prevalence overall was 25.5% (n = 199,818) with a minor increasing trend: 25.3% (n = 7,828) in 2003 to 28.9% (n = 19,275) in 2016; p < 0.0001. Median total hospitalization costs for PJI decreased slightly ($23,247 in 2003–$20,273 in 2016; p < 0.0001) while median per-day costs slightly increased ($3,452 in 2003–$3,727 in 2016; p < 0.0001), likely as a function of decreasing length of stay. With small differences between hospitals, the lowest and highest PJI prevalences were seen in small (≤299 beds; 22.9%) and urban teaching hospitals (27.3%), respectively. In stratification analyses, an increasing trend in PJI prevalence was particularly seen in larger (≥500 beds) hospitals (24.4% in 2003–30.7% in 2016; p < 0.0001), while a decreasing trend was seen in small-sized hospitals. Overall, PJI in knee arthroplasty revisions appears to be slightly increasing. Moreover, increasing trends in large hospitals and decreasing trends in small-sized hospitals suggest a shift in patients from small to large volume hospitals. Decreasing trends in total costs, alongside increasing trends in per-day costs, suggest a strong impact of length of stay trends and a more efficient approach to PJI over the years (in terms of shorter length of stay).

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