scholarly journals Long time series of daily evapotranspiration in China based on the SEBAL model and multisource images and validation

2021 ◽  
Vol 13 (8) ◽  
pp. 3995-4017
Author(s):  
Minghan Cheng ◽  
Xiyun Jiao ◽  
Binbin Li ◽  
Xun Yu ◽  
Mingchao Shao ◽  
...  
Keyword(s):  
Time Series ◽  
Water Resources ◽  
Observational Data ◽  
Water Resources Management ◽  
Environmental Conditions ◽  
Scale Validation ◽  
Point Scale ◽  
Resources Management ◽  
Basin Scale ◽  
Long Time

Abstract. Satellite observations of evapotranspiration (ET) have been widely used for water resources management in China. An accurate ET product with a high spatiotemporal resolution is required for research on drought stress and water resources management. However, such a product is currently lacking. Moreover, the performances of different ET estimation algorithms for China have not been clearly studied, especially under different environmental conditions. Therefore, the aims of this study were as follows: (1) to use multisource images to generate a long-time-series (2001–2018) daily ET product with a spatial resolution of 1 km × 1 km based on the Surface Energy Balance Algorithm for Land (SEBAL); (2) to comprehensively evaluate the performance of the SEBAL ET in China using flux observational data and hydrological observational data; and (3) to compare the performance of the SEBAL ET with the MOD16 ET product at the point scale and basin scale under different environmental conditions in China. At the point scale, both the models performed best in the conditions of forest cover, subtropical zones, hilly terrain, or summer, respectively, and SEBAL performed better in most conditions. In general, the accuracy of the SEBAL ET (rRMSE = 44.91 %) was slightly higher than that of the MOD16 ET (rRMSE = 48.72 %). In the basin-scale validation, both the models performed better than in the point-scale validation, with SEBAL obtaining results superior (rRMSE = 13.57 %) to MOD16 (rRMSE = 32.84 %). Additionally, both the models showed a negative bias, with the bias of the MOD16 ET being higher than that of the SEBAL ET. In the daily-scale validation, the SEBAL ET product showed a root mean square error (RMSE) of 0.92 mm d−1 and an r value of 0.79. In general, the SEBAL ET product can be used for the qualitative analysis and most quantitative analyses of regional ET. The SEBAL ET product is freely available at https://doi.org/10.5281/zenodo.4243988 and https://doi.org/10.5281/zenodo.4896147 (Cheng, 2020a, b). The results of this study can provide a reference for the application of remotely sensed ET products and the improvement of satellite ET observation algorithms.

scholarly journals Long time series of daily evapotranspiration in China based on the SEBAL model and multisource images and validation

2020 ◽  
Author(s):  
Minghan Cheng ◽  
Xiyun Jiao ◽  
Binbin Li ◽  
Xun Yu ◽  
Mingchao Shao ◽  
...  
Keyword(s):  
Time Series ◽  
Water Resources ◽  
Observational Data ◽  
Water Resources Management ◽  
Environmental Conditions ◽  
Scale Validation ◽  
Point Scale ◽  
Resources Management ◽  
Basin Scale ◽  
Long Time

Abstract. Satellite observations of evapotranspiration (ET) have been widely used for water resources management in China. An accurate ET product with a high spatiotemporal resolution is required for research on drought stress and water resources management. However, such a product is currently lacking. Moreover, the performances of different ET estimation algorithms for China have not been clearly studied, especially under different environmental conditions. Therefore, the aims of this study were as follows: (1) to use multisource images to generate a long time series (2001–2018) daily ET product with a spatial resolution of 1 km × 1 km based on the Surface Energy Balance Algorithm for Land (SEBAL); (2) to comprehensively evaluate the performance of the SEBAL ET in China using flux observational data and hydrological observational data; (3) to compare the performance of the SEBAL ET with the MOD16 ET product at the point-scale and basin-scale under different environmental conditions in China. At the point-scale, both the models performed best in the conditions of forest cover, subtropical zones, hilly terrain, or summer, respectively, and SEBAL performed better in most conditions. In general, the accuracy of the SEBAL ET (rRMSE = 44.91 %) was slightly higher than that of the MOD16 ET (rRMSE = 48.72 %). In the basin-scale validation, both the models performed better than in the point-scale validation, with SEBAL obtaining superior results (rRMSE = 19.15 %) to MOD16 (rRMSE = 33.62 %). Additionally, both the models showed a negative bias, with the bias of the MOD16 ET being higher than that of the SEBAL ET. In the daily-scale validation, the SEBAL ET product showed an RMSE of 0.92 mm/d and an r-value of 0.79. In general, the SEBAL ET product can be used for the qualitative analysis and most quantitative analysis of regional ET. SEBAL ET product is freely available at https://doi.org/10.5281/zenodo.4218413 (Cheng, 2020). The results of this study can provide a reference for the application of remotely sensed ET products and the improvement of satellite ET observation algorithms.

scholarly journals Assessment of Groundwater Resource in Climate Variability Context at Sinematiali (North of Côte d'Ivoire)

2020 ◽  
Vol 1 (5) ◽  
Author(s):  
Omer Zephir De Lasme ◽  
Avy Stephane Koffi ◽  
Dodo Guy Gnali Cedric
Keyword(s):  
Time Series ◽  
Water Resources ◽  
Climate Variability ◽  
Water Resources Management ◽  
Integrated Water Resources Management ◽  
Statistical Test ◽  
Groundwater Resource ◽  
Resources Management ◽  
Pettitt Test ◽  
Software Models

Study of climate variability gets great importance for integrated water resources management. This work examines impact of climate variability on the evolution of water resources in the Bandama sub-watershed at Sinematiali with a view of better management. The time series of rainfall and discharge were used as a database for this purpose. Known calculation hydrologic methods of Nicholson, Maillet as well as the statistical test for breaking detection (Pettitt test) were applied. The effective rain and recharge were estimated by using the ESPERE software models over the period 1980 to 1987. Climate variability is characterized by alternative season of wet, normal, and dry periods, and a pluviometry break occurred in 1984 year. The annual effective rain was assessed from 30 to 570 mm while recharge of aquifers estimated between 2 and 333 mm. This work constitutes a fundamental base for modeling water resources management at Sinematiali.

scholarly journals The water dispatching of river basins during dry periods under the most stringent water management system in China

Water Policy ◽  
2021 ◽  
Author(s):  
Yanhu He ◽  
Zhenjie Gong ◽  
Yanhui Zheng ◽  
Xiaoyan Bai ◽  
Peng Wang
Keyword(s):  
Water Management ◽  
Water Resources ◽  
River Basin ◽  
Water Resources Management ◽  
Management System ◽  
River Basins ◽  
Water Management System ◽  
Resources Management ◽  
Basin Scale ◽  
Utilization Ratio

Abstract Since 2011, China has implemented its most stringent water management system to effectively protect water resources and guarantee socioeconomic development. More basin-scale water division schemes have been developed to act as references for basin-scale water resources management. Water dispatching during dry periods is an effective way to guarantee the water supply for the river basin, and is also an important component of basin-scale water resources management. Given this, the present study proposes a framework for the water dispatching of river basins during dry periods under the most stringent water management system in China. This framework mainly consists of the analysis and forecasting of rainfall and inflow, the dispatching requirements for the main water users, major reservoirs, and sections, as well as safeguard measures. The Jian River Basin in South China is presented as a case study. The total discharge of the Gaozhou Reservoir in 2017 was 25 million m3 more than the target discharge specified in the water dispatching scheme, and the total water storage utilization ratio during the dispatch period was 4.7% higher than the target utilization ratio. These factors demonstrate the effectiveness and applicability of the proposed framework. HIGHLIGHT The proposed framework for the water dispatching of river basins during dry periods provides reliable technical support for water use security under the most stringent water management system in China, and is demonstrated to be both effective and applicable.

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