scholarly journals Sensitivity analysis of potential evapotranspiration to key climatic factors in the Shiyang River Basin

2020 ◽  
Author(s):  
Xuelei Zhang ◽  
Weihua Xiao ◽  
Yicheng Wang ◽  
Yan Wang ◽  
Miaoye Kang ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
River Basin ◽  
Air Temperature ◽  
Climatic Factors ◽  
Potential Evapotranspiration ◽  
Mountainous Region ◽  
Shiyang River Basin ◽  
Increasing Trends ◽  
Maximum Air Temperature ◽  
Monteith Equation

Abstract This paper focuses on determining the spatial and temporal characteristics of the sensitivity coefficients (SCs) between potential evapotranspiration (ET0) and key climatic factors across the Shiyang River Basin (SYRB) from 1981 to 2015. Penman–Monteith equation and a sensitivity analysis were used to calculate ET0 and the SCs for key climatic factors. Sen's slope was used to analyze the observed series. According to the results, the sensitivity significances were in the order of relative humidity (RH) > net solar radiation (NSR) > wind speed (WS) > maximum air temperature (Tmax) > minimum air temperature (Tmin). The SCs for the RH and NSR were larger in the upper mountainous region, while the other three coefficients were larger in the middle and lower reaches. All five climatic factors for the ET0 SCs showed increasing trends in the mountainous region, and the Tmax, WS and RH SCs increased in the middle and lower reaches. Over the past 35 years, the change in ET0 was dominated by the air temperature (T), RH and NSR, and the increase in ET0 during the studied period was mainly due to the increases in T and NSR.

scholarly journals Copula-Based Abrupt Variations Detection in the Relationship of Seasonal Vegetation-Climate in the Jing River Basin, China

2019 ◽  
Vol 11 (13) ◽  
pp. 1628 ◽  
Author(s):  
Jing Zhao ◽  
Shengzhi Huang ◽  
Qiang Huang ◽  
Hao Wang ◽  
Guoyong Leng ◽  
...  
Keyword(s):  
River Basin ◽  
Human Activities ◽  
Urban Areas ◽  
Large Scale ◽  
Vegetation Index ◽  
Climatic Factors ◽  
Potential Evapotranspiration ◽  
Change Points ◽  
Vegetation Coverage ◽  
The Relationship

Understanding the changing relationships between vegetation coverage and precipitation/temperature (P/T) and then exploring their potential drivers are highly necessary for ecosystem management under the backdrop of a changing environment. The Jing River Basin (JRB), a typical eco-environmentally vulnerable region of the Loess Plateau, was chosen to identify abrupt variations of the relationships between seasonal Normalized Difference Vegetation Index (NDVI) and P/T through a copula-based method. By considering the climatic/large-scale atmospheric circulation patterns and human activities, the potential causes of the non-stationarity of the relationship between NDVI and P/T were revealed. Results indicated that (1) the copula-based framework introduced in this study is more reasonable and reliable than the traditional double-mass curves method in detecting change points of vegetation and climate relationships; (2) generally, no significant change points were identified during 1982–2010 at the 95% confidence level, implying the overall stationary relationship still exists, while the relationships between spring NDVI and P/T, autumn NDVI and P have slightly changed; (3) teleconnection factors (including Arctic Oscillation (AO), Pacific Decadal Oscillation (PDO), Niño 3.4, and sunspots) have a more significant influence on the relationship between seasonal NDVI and P/T than local climatic factors (including potential evapotranspiration and soil moisture); (4) negative human activities (expansion of farmland and urban areas) and positive human activities (“Grain For Green” program) were also potential factors affecting the relationship between NDVI and P/T. This study provides a new and reliable insight into detecting the non-stationarity of the relationship between NDVI and P/T, which will be beneficial for further revealing the connection between the atmosphere and ecosystems.

scholarly journals Evaluation of Open Access Precipitation and Temperature Products Using SWAT in Shiyang River Basin, Northwest China

2020 ◽  
Author(s):  
Gengxi Zhang ◽  
Xiaoling Su ◽  
Olusola O. Ayantobo ◽  
Kai Feng ◽  
Jing Guo
Keyword(s):  
Open Access ◽  
River Basin ◽  
Air Temperature ◽  
Assessment Tool ◽  
Swat Model ◽  
Northwest China ◽  
Promising Alternative ◽  
Shiyang River Basin ◽  
Streamflow Simulation ◽  
Precipitation And Temperature

Precipitation and temperature are significant inputs for hydrological models. Currently, many satellite and reanalysis precipitation and air temperature datasets exist at different spatio-temporal resolutions at a global and quasi-global scale. This study evaluated the performances of three open-access precipitation datasets (gauge-adjusted research-grade Global Satellite Mapping of Precipitation (GSMaP_Gauge), Climate Hazards Group Infrared Precipitation with Station data (CHIRPS), Climate Forecast System Reanalysis(CFSR)) and CFSR air temperature dataset in driving the Soil and Water Assessment Tool (SWAT) model required for the monthly simulation of streamflow in the upper Shiyang River Basin of northwest China. After a thorough comparison of six model scenarios with different combinations of precipitation and air temperature inputs, the following conclusions were drawn: (1) Although the precipitation products had similar spatial patterns, however, CFSR differs significantly by showing an overestimation; (2) CFSR air temperature yielded almost identical performance in the streamflow simulation than the measured air temperature from gauge stations; (3) among the three open-access precipitation datasets, CHIRPS produced the best performance. These results suggested that the CHIRPS precipitation and CFSR air temperature datasets which are available at high spatial resolution (0.05), could be a promising alternative open-access data source for streamflow simulation in the case of limited access to desirable gauge data in the data-scarce area.

scholarly journals Effects of Climate Variability on Evaporation in Dongping Lake, China, during 2003–2010

2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
Yuan Rong ◽  
Hongbo Su ◽  
Renhua Zhang ◽  
Zheng Duan
Keyword(s):  
Wind Velocity ◽  
Air Temperature ◽  
Climatic Factors ◽  
Net Radiation ◽  
Evaporation Ratio ◽  
Dongping Lake ◽  
Lake Evaporation ◽  
Annual Evaporation ◽  
Monteith Equation

Based on two long-term, hourly (10:30–11:30 and 13:10–14:10) meteorological over-lake observations and data from Shenxian meteorological station, nearby Dongping Lake, the Penman-Monteith equation and reference evaporation ratio algorithm were used to calculate lake evaporation in Dongping Lake, China, from 2003 to 2010. The variation trend of evaporation of Dongping Lake was analyzed, and the influences that caused changes in lake evaporation were also discussed. The results show that (1) the total annual evaporation in Dongping Lake increased at 18.24 mm/a during 2003–2010. The major climatic factors accounting for this increase are the rising net radiation and the rising air temperature; (2) the total annual evaporation in a particular hour (13:10–14:10) in Dongping Lake increased at 4.55 mm/a during 2003–2010—the major climate factors that accounted for this increase are rising net radiation, followed by air temperature, wind velocity, and air humidity; (3) against the background of global warming, the climate of Dongping Lake tended to be dry during 2003–2010; the largest contribution to this comes from air temperature, followed by wind velocity and relative humidity; and (4) the monthly evaporation in Dongping Lake has seasonal variability.

scholarly journals Multi-Model Projections of Climate Change in Different RCP Scenarios in an Arid Inland Region, Northwest China

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 347 ◽  
Author(s):  
Ruotong Wang ◽  
Qiuya Cheng ◽  
Liu Liu ◽  
Churui Yan ◽  
Guanhua Huang
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Air Temperature ◽  
Northwest China ◽  
Heihe River Basin ◽  
Heihe River ◽  
Rcp Scenarios ◽  
Maximum Air Temperature ◽  
The Heihe River Basin ◽  
Minimum Air Temperature

Based on three IPCC (Intergovernmental Panel on Climate Change) Representative Concentration Pathway (RCP) scenarios (RCP2.6, RCP4.5, and RCP8.5), observed meteorological data, ERA-40 reanalysis data, and five preferred GCM (general circulation model) outputs selected from 23 GCMs of CMIP5 (Phase 5 of the Coupled Model Intercomparison Project), climate change scenarios including daily precipitation, maximum air temperature, and minimum air temperature from 2021 to 2050 in the Heihe River basin, which is the second largest inland river basin in Northwest China, were generated by constructing a statistical downscaling model (SDSM). Results showed that the SDSM had a good prediction capacity for the air temperature in the Heihe River basin. During the calibration and validation periods from 1961 to 1990 and from 1991 to 2000, respectively, the coefficient of determination (R2) and the Nash–Sutcliffe efficiency coefficient (NSE) were both larger than 0.9, while the root mean square error (RMSE) was within 20%. However, the SDSM showed a relative lower simulation efficiency for precipitation, with R2 and NSE values of most meteorological stations reaching 0.5, except for stations located in the downstream desert areas. Compared with the baseline period (1976–2005), changes in the annual mean precipitation simulated by different GCMs during 2021–2050 showed great difference in the three RCP scenarios, fluctuating from −10 to +10%, which became much more significant at seasonal and monthly time scales, except for the consistent decreasing trend in summer and increasing trend in spring. However, the maximum and minimum air temperature exhibited a similar increasing tendency during 2021–2050 in all RCP scenarios, with a higher increase in maximum air temperature, which increased as the CO2 concentration of the RCP scenarios increased. The results could provide scientific reference for sustainable agricultural production and water resources management in arid inland areas subject to climate change.

scholarly journals Influence of Meteorological Factors on the Potential Evapotranspiration in Yanhe River Basin, China

2021 ◽  
Author(s):  
yu luo ◽  
Peng Gao ◽  
Xingmin Mu
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
River Basin ◽  
Air Temperature ◽  
Hydrological Cycle ◽  
Meteorological Factors ◽  
Potential Evapotranspiration ◽  
Sensitivity Coefficients ◽  
The Impact

Potential evapotranspiration (ET) is an essential component of the hydrological cycle, and quantitative estimation of the influence of meteorological factors on ET can provide a scientific basis for studying the impact mechanisms of climate change. In the present research, the Penman-Monteith method was used to calculate ET. The Mann-Kendall statistical test with the inverse distance weighting were used to analyze the spatiotemporal characteristics of the sensitivity coefficients and contribution rates of meteorological factors to ET to identify the mechanisms underlying changing ET rates. The results showed that the average ET for the Yanhe River Basin, China from 1978–2017 was 935.92 mm. Save for a single location (Ganquan), ET increased over the study period. Generally, the sensitivity coefficients of air temperature (0.08), wind speed at 2 m (0.19), and solar radiation (0.42) were positive, while that of relative humidity was negative (-0.41), although significant spatiotemporal differences were observed. Increasing air temperature and solar radiation contributed 1.09% and 0.55% of the observed rising ET rates, respectively; whereas decreasing wind speed contributed -0.63%, and relative humidity accounted for -0.85%. Therefore, it was concluded that the decrease of relative humidity did not cause the observed ET increase in the basin. The predominant factor driving increasing ET was rising air temperatures, but this too varied significantly by location and time (intra- and interannually). Decreasing wind speed at Ganquan Station decreased ET by -9.16%, and was the primary factor underlying the observed, local “evaporation paradox.” Generally, increases in ET were driven by air temperature, wind speed and solar radiation, whereas decreases were derived from relative humidity.

scholarly journals Hydro-Meteorological Trends in the Upper Omo-Ghibe River Basin, Ethiopia

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1951 ◽  
Author(s):  
Jaweso ◽  
Abate ◽  
Bauwe ◽  
Lennartz
Keyword(s):  
River Basin ◽  
Air Temperature ◽  
Data Availability ◽  
Change Points ◽  
Annual Rainfall ◽  
Significance Level ◽  
Annual Time Scale ◽  
Planning Decisions ◽  
Increasing Trends ◽  
Annual Time

This study aimed to assess trends of hydro-meteorological variables in the Upper Omo-Ghibe river basin, Ethiopia. Data records from eleven rainfall, eight air temperature, and five streamflow stations between 1981 to 2008 were investigated. The trends and change points were evaluated for different periods of time depending on data availability. Mann-Kendall and Pettit tests were used to identify trends and change points at a 5% significance level. The tests were applied to mean annual, monthly and seasonal time scales. Rainfall exhibited statistically decreasing trends at a mean annual time scale, while seasonal rainfall depicted heterogeneous results in both directions. For the majority of the stations, air temperature showed statistically significant increasing trends. The magnitude of change in temperature for mean annual, wet and dry season has increased about 0.48, 0.46, and 0.61 °C per decade for Jimma station. The Pettit test revealed that the late 1980s and 1990s were the change points. There is generally a decreasing trend in streamflow. The decline in annual rainfall and rise in temperature affected the streamflow negatively. Overall, the results indicate that trend sand change point times varied considerably across the stations and catchments. The identified significant trends can help to support planning decisions for water management.

scholarly journals Innovative Trend Analysis of Air Temperature and Precipitation in the Jinsha River Basin, China

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3293
Author(s):  
Zengchuan Dong ◽  
Wenhao Jia ◽  
Ranjan Sarukkalige ◽  
Guobin Fu ◽  
Qing Meng ◽  
...  
Keyword(s):  
Climate Change ◽  
Trend Analysis ◽  
River Basin ◽  
Air Temperature ◽  
Climatic Factors ◽  
Trend Detection ◽  
Spatial Pattern Analysis ◽  
Jinsha River ◽  
Temperature And Precipitation ◽  
Innovative Trend Analysis

Trend detection based on hydroclimatological time series is crucial for understanding climate change. In this study, the innovative trend analysis (ITA) method was applied to investigate trends in air temperature and precipitation over the Jinsha River Basin (JRB), China, from 1961 to 2016 based on 40 meteorological stations. Climatic factors series were divided into three categories according to percentile, and the hidden trends were evaluated separately. The ITA results show that annual and seasonal temperatures have significantly increased whereas the variation range of annual temperature tended to narrow. Spatial pattern analysis of the temperature indicates that high elevation areas show more increasing trends than flat areas. Furthermore, according to ITA, significant increase trends are observed in annual precipitation and “high” category of spring precipitation. The sub-basins results show a significant decreasing trend in elevation zones of ≤2000 m and an increasing trend where elevation is >2000 m. Moreover, linkage between temperature and precipitation was analyzed and the potential impact of the combined changes was demonstrated. The results of this study provide a reference for future water resources planning in the JRB and will help advance the understanding of climate change in similar areas.

scholarly journals Influence of Meteorological Factors on the Potential Evapotranspiration in Yanhe River Basin, China

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1222
Author(s):  
Yu Luo ◽  
Peng Gao ◽  
Xingmin Mu
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
River Basin ◽  
Air Temperature ◽  
Hydrological Cycle ◽  
Meteorological Factors ◽  
Potential Evapotranspiration ◽  
Sensitivity Coefficients ◽  
The Impact

Potential evapotranspiration (ET0) is an essential component of the hydrological cycle, and quantitative estimation of the influence of meteorological factors on ET0 can provide a scientific basis for studying the impact mechanisms of climate change. In the present research, the Penman–Monteith method was used to calculate ET0. The Mann–Kendall statistical test with the inverse distance weighting were used to analyze the spatiotemporal characteristics of the sensitivity coefficients and contribution rates of meteorological factors to ET0 to identify the mechanisms underlying changing ET0 rates. The results showed that the average ET0 for the Yanhe River Basin, China from 1978–2017 was 935.92 mm. Save for a single location (Ganquan), ET0 increased over the study period. Generally, the sensitivity coefficients of air temperature (0.08), wind speed at 2 m (0.19), and solar radiation (0.42) were positive, while that of relative humidity was negative (−0.41), although significant spatiotemporal differences were observed. Increasing air temperature and solar radiation contributed 1.09% and 0.55% of the observed rising ET0 rates, respectively; whereas decreasing wind speed contributed −0.63%, and relative humidity accounted for −0.85%. Therefore, it was concluded that the decrease of relative humidity did not cause the observed ET0 increase in the basin. The predominant factor driving increasing ET0 was rising air temperatures, but this too varied significantly by location and time (intra- and interannually). Decreasing wind speed at Ganquan Station decreased ET0 by −9.16%, and was the primary factor underlying the observed, local “evaporation paradox”. Generally, increase in ET0 was driven by air temperature, wind speed and solar radiation, whereas decrease was derived from relative humidity.

scholarly journals Responses of snowmelt runoff to climatic change in an inland river basin, Northwestern China, over the past 50a

2010 ◽  
Vol 7 (1) ◽  
pp. 493-528 ◽  
Author(s):  
J. Wang ◽  
H.-Y. Li ◽  
X.-H. Hao
Keyword(s):  
Climatic Change ◽  
River Basin ◽  
Air Temperature ◽  
Heihe River Basin ◽  
Northwestern China ◽  
Heihe River ◽  
Observation Data ◽  
Mountainous Region ◽  
Snowmelt Runoff ◽  
The Past

Abstract. The spatial and temporal variations of snowcover distribution, and snowmelt runoffs are considered as sensitive indicators for climatic change. The purpose of this paper is to analyze and forecast the responses of snowmelt runoff to climate change. The upstream of Heihe River Basin in Northwestern China was chose as the representative catchments, and the observation data of the meteorological and hydrological stations were utilized to analyze the status and the regularity for the climatic change from 1956 to 2008. Moderate Resolution Imaging Spectroradiometer (MODIS) data were used to develop an optimized technology for snow mapping in the mountainous region. Snowmelt Runoff Model (SRM) was chose to simulate snowmelt runoff and scenario forecast the change trend of snowmelt runoff in catchment scale for the mountainous region in Northwestern China. The results show that climatic warming was apparent in the upstream of Heihe River Basin in the past 50a. Annual average air temperature of three different weather stations located in the basin has increased 2.1 °C, 2.6 °C and 2.9 °C, respectively. The snowmelt runoff has increased obviously from 1970 to present. With different warming climate scenarios, the results by SRM simulating showed that the first occurred time of snowmelt runoff shift ahead and discharge become larger as responses of snowmelt runoff to air temperature increasing, and the influence of temperature rising on average discharge of the whole snow season is not obvious. On the other hand, simulated discharge showed a marked increase trend with the increase of precipitation. And, the simulated results show that the increase of precipitation almost has no influence on the occurring time of snowmelt runoff.

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