Spatiotemporal Variability of Potential Evaporation in Heihe River Basin Influenced by Irrigation

2020 ◽  
Author(s):  
Congying Han
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Spatial Pattern ◽  
River Basin ◽  
Meteorological Factors ◽  
Heihe River Basin ◽  
Spatiotemporal Variability ◽  
Maximum Temperature ◽  
Heihe River ◽  
Potential Evaporation

<p><strong>Spatiotemporal Variability of Potential Evaporation in Heihe River Basin Influenced by Irrigation </strong></p><p>Congying Han<sup>1,2</sup>, Baozhong Zhang<sup>1,2</sup>, Songjun Han<sup>1,2</sup></p><p><sup>1</sup> State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China.</p><p><sup>2</sup> National Center of Efficient Irrigation Engineering and Technology Research-Beijing, Beijing 100048, China.</p><p>Corresponding author: Baozhong Zhang ([email protected])</p><p><strong>Abstract: </strong>Potential evaporation is a key factor in crop water requirement estimation and agricultural water resource planning. The spatial pattern and temporal changes of potential evaporation calculated by Penman equation (E<sub>Pen</sub>) (1970-2017) in Heihe River Basin (HRB), Northwest China were evaluated by using data from 10 meteorological stations, with a serious consideration of the influences of irrigation development. Results indicated that the spatial pattern of annual E<sub>Pen</sub> in HRB was significantly different, among which the E<sub>Pen</sub> of agricultural sites (average between 1154 mm and 1333 mm) was significantly higher than that of natural sites (average between 794 mm and 899 mm). Besides, the coefficient of spatial variation of the aerodynamic term (E<sub>aero</sub>) was 0.4, while that of the radiation term (E<sub>rad</sub>) was 0.09. The agricultural irrigation water withdrawal increased annually before 2000, but decreased significantly after 2000 which was influenced by the agricultural development and the water policy. Coincidentally, the annual variation of E<sub>pen</sub> in agricultural sites decreased at -40 mm/decade in 1970-2000 but increased at 60 mm/decade in 2001-2017, while that in natural sites with little influence of irrigation, only decreased at -0.5mm/decade in 1970-2000 but increased at 11 mm/decade in 2001-2017. So it was obvious that irrigation influenced E<sub>pen </sub>significantly and the change of E<sub>pen</sub> was mainly caused by the aerodynamic term. The analysis of the main meteorological factors that affect E<sub>pen</sub> showed that wind speed had the greatest impact on E<sub>pen</sub> of agricultural sites, followed by relative humidity and average temperature, while the meteorological factors that had the greatest impact on E<sub>pen</sub> of natural sites were maximum temperature, followed by wind speed and relative humidity.</p>

scholarly journals Estimation of the Influence of Meteorological Factors on the Potential Evapotranspiration of Yanhe River Basin

2021 ◽  
Author(s):  
yu luo ◽  
Peng Gao ◽  
Xingmin Mu ◽  
dexun Qiu
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
River Basin ◽  
Air Temperature ◽  
Meteorological Factors ◽  
Sensitivity Coefficient ◽  
Downward Trend ◽  
Upward Trend ◽  
Temporal And Spatial

Potential evapotranspiration (ET) is an important expenditure item in the hydrological cycle. Quantitative estimation of the influence of meteorological factors on ET can provide a scientific basis for the study of the impact mechanism of climate change on the hydrological cycle. In this paper, the Penman-Monteith method was used to calculate ET. The Mann-Kendall statistical test and the Inverse Distance Weighting method were used to analyze the temporal and spatial characteristics of the sensitivity coefficient of ET to meteorological factors and contribution rate of meteorological factors to ET. And the reasons for the change of ET were quantitatively explored in combination with the change trend of meteorological factors. The results showed that the average ET in the Yanhe River Basin from 1978 to 2017 was 935.92mm. Except for Ganquan Station, ET showed an upward trend. Generally, the sensitivity coefficient of air temperature (0.08), wind speed (0.19) and solar radiation (0.42) was positive and the sensitivity coefficient of relative humidity (-0.41) was negative. But there were significant temporal and spatial differences. The upward trend of air temperature and solar radiation contributed 1.09% and 0.55% to ET. Respectively, the downward trend of wind speed contributed -0.63% And the downward trend of relative humidity contributed to -0.85% of ET. Therefore, the decrease of relative humidity did not cause the increase of ET in Yanhe River basin. The dominant factor of the upward trend of ET was air temperature. But the dominant factors of ET had significant temporal and spatial differences. The downward trend of wind speed at Ganquan Station contributed -9.16% to ET, which indicated the dominant factor of “evaporation paradox” in Ganquan area was wind speed. Generally, the increase of ET was related to air temperature, wind speed and solar radiation. And the decrease of ET was related to relative humidity.

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 Trend and Sensitivity Analysis of Reference Evapotranspiration in the Senegal River Basin Using NASA Meteorological Data

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1957
Author(s):  
Papa Malick Ndiaye ◽  
Ansoumana Bodian ◽  
Lamine Diop ◽  
Abdoulaye Deme ◽  
Alain Dezetter ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Wind Speed ◽  
Relative Humidity ◽  
River Basin ◽  
Reference Evapotranspiration ◽  
Climatic Variables ◽  
Maximum Temperature ◽  
Senegal River ◽  
Senegal River Basin ◽  
Basin Area

Understanding evapotranspiration and its long-term trends is essential for water cycle studies, modeling and for water uses. Spatial and temporal analysis of evapotranspiration is therefore important for the management of water resources, particularly in the context of climate change. The objective of this study is to analyze the trend of reference evapotranspiration (ET0) as well as its sensitivity to climatic variables in the Senegal River basin. Mann-Kendall’s test and Sen’s slope were used to detect trends and amplitude changes in ET0 and climatic variables that most influence ET0. Results show a significant increase in annual ET0 for 32% of the watershed area over the 1984–2017 period. A significant decrease in annual ET0 is observed for less than 1% of the basin area, mainly in the Sahelian zone. On a seasonal scale, ET0 increases significantly for 32% of the basin area during the dry season and decreases significantly for 4% of the basin during the rainy season. Annual maximum, minimum temperatures and relative humidity increase significantly for 68%, 81% and 37% of the basin, respectively. However, a significant decrease in wind speed is noted in the Sahelian part of the basin. The wind speed decrease and relative humidity increase lead to the decrease in ET0 and highlight a “paradox of evaporation” in the Sahelian part of the Senegal River basin. Sensitivity analysis reveals that, in the Senegal River basin, ET0 is more sensitive to relative humidity, maximum temperature and solar radiation.

scholarly journals Reference Evapotranspiration Changes: Sensitivities to and Contributions of Meteorological Factors in the Heihe River Basin of Northwestern China (1961–2014)

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Chaoyang Du ◽  
Jingjie Yu ◽  
Ping Wang ◽  
Yichi Zhang
Keyword(s):  
Sensitivity Analysis ◽  
River Basin ◽  
Reference Evapotranspiration ◽  
Meteorological Factors ◽  
Heihe River Basin ◽  
Heihe River ◽  
Negative Contribution ◽  
Sensitive Factor ◽  
Increasing Trend ◽  
The Heihe River Basin

This paper investigates reference evapotranspiration(ET0)changes, sensitivities to and contributions of meteorological factors in the Heihe River Basin (arid and inland region). Results show that annualET0over the whole basin has increasing trend (2.01 mm·10 yr−2) and there are significant increasing spatial variations from the upper (753 mm yr−1) to the lower (1553 mm yr−1) regions. Sensitivity analysis indicates that relative humidity is the most sensitive factor for seasonal and annualET0change, and the influence is negative. The sensitivity of minimum temperature is the weakest and negative. Contribution analysis shows that the main contributors toET0changes are aerodynamic factors rather than radiative factors. This study could be helpful to understand the response of ecoenvironment to the meteorological factors changes in the Heihe River Basin.

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.

Temporal variations of reference evapotranspiration in Heihe River basin of China

2012 ◽  
Vol 44 (5) ◽  
pp. 904-916 ◽  
Author(s):  
Zhanling Li ◽  
Zhanjie Li ◽  
Zongxue Xu ◽  
Xun Zhou
Keyword(s):  
River Basin ◽  
Influence Factor ◽  
Reference Evapotranspiration ◽  
Temporal Variations ◽  
Heihe River Basin ◽  
Maximum Temperature ◽  
Heihe River ◽  
Agricultural Crop ◽  
Different Seasons ◽  
Increasing Trends

Temporal variations in reference evapotranspiration (ETo) have profound implications for hydrological processes as well as for agricultural crop performance. The main aim of this study was to analyze the annual, seasonal trends in ETo in the Heihe River basin. The likely causative meteorological variables for such temporal changes in ETo were also identified. Results showed that, on a seasonal and annual scale, ETo for the upper reach showed increasing trends from 1960 to 2010; both increasing and decreasing trends were observed for the middle and lower reaches. In spring, wind speed (WS) and relative humidity (RH) were the most likely causative variables for changes of ETo for the whole basin; in summer and autumn, maximum temperature (Tmax) and RH contributed more to the trends in ETo for the upper reach, and WS contributed more for the middle and lower reaches; in winter, Tmax, WS and RH contributed more in different locations and in different seasons. From the spatial perspective, WS, RH and Tmax contributed more to the changes of ETo in the upper reach; WS was the main likely influence factor in the middle reach, and WS and RH were the probable main factors in the lower reach.

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