Yi, Ze-ji; Yang, Xiao-hua; Li, Yu-qi. (2022). A Water Quality Prediction Model for Large-scale Rivers Based on Projection Pursuit Regression in the Yangtze River. Thermal Science, 26(3), 2561-2567.
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Abstract
In recent decades, the Yangtze River Basin, which carries hundreds of millions of people and a substantial economic scale, has been plagued by water quality dete-rioration, threatening considerably sustainable development. In this paper, a sample set is established based on the water quality indexes of chemical oxygen demand and dissolved oxygen obtained by week-by-week monitoring on the main stream of the Yangtze River in Panzhihua, Yueyang, Jiujiang, and Nanjing from 2006 to 2018. The twelve characteristic variables are selected by random forest technique, and the week-by-week dynamic prediction models of chemical oxygen demand and dissolved oxygen at each section of main stream are established by the projection pursuit regression, which can effectively predict the water quality dynamics of the Yangtze River main stream.
Keywords
Pollution; Water Quality; Dynamic Prediction Model; Random Forest; Projection Pursuit Regression; Yangtze River
Wang, Kaiwen; Liu, Xiaomang; Li, Yuqi; Yang, Xiaohua; Bai, Peng; Liu, Changming; Chen, Fei. (2019). Deriving a Long-Term Pan Evaporation Reanalysis Dataset for Two Chinese Pan Types. Journal Of Hydrology, 579.
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Abstract
A long-term continuous and consistent pan evaporation (E-pan) reanalysis dataset will augment the analysis of E-pan distributions when the observation network is discontinuous or inconsistent, and assist in the evaluation of the outputs of General Circulation Models (GCMs) and Land Surface Models (LSMs). From the 1950s to early 2000s, China had a continuous observation of the D20 pan, but this was replaced by the 601B pan across China around 2002, and thus the E-pan observation network became discontinuous and inconsistent. This study developed a long-term monthly, 0.05 degrees, continuous and consistent reanalysis dataset for both D20 and 6018 pans covering mainland China throughout 1960-2014, based on meteorological data homogenization and interpolation and E-pan assimilation. The PenPan-V3 model used inE(pan) assimilation was successfully validated by observations at 767 and 591 stations for D20 and 601B pans, respectively. Comprehensively considering the physical influence of elevation, radiation, wind speed, humidity, and air temperature, the average annual and seasonal gridded E-pan reanalyses show significant spatial dependent on proximity to the ocean and latitude, consistent with previous studies. The reanalysis dataset can be used to analyze E-pan distributions across China, including the areas without observations, and to estimate the representativeness of E-pan to atmospheric evaporative demand. The dataset has been released in two cloud servers in China and the United States, and it will continue to be maintained and updated.
Keywords
General Circulation Model; Evaporation (meteorology); Atmospheric Temperature; Wind Speed; China; Long-term Continuous And Consistent Dataset; Pan Evaporation Reanalysis Dataset; Representativeness To Atmospheric Evaporative Demand; Maximal T-test; Reference Evapotranspiration; Climate Data; Energy-balance; Reference Crop; Trends; Water; Model; Demand; General Circulation Models; Air Temperature; Data Collection; Evaporation; Evaporative Demand; Humidity; Latitude; Meteorological Data; United States
Wang, Kaiwen; Liu, Xiaomang; Liu, Changming; Yang, Xiaohua; Bai, Peng; Li, Yuqi; Pan, Zharong. (2019). The Unignorable Impacts of Pan Wall on Pan Evaporation Dynamics. Agricultural & Forest Meteorology, 274, 42 – 50.
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Abstract
Open water evaporation (E-ow), such as evaporation of lake and reservoir, is typically estimated by observations of different pans. The observation networks of pan evaporation (E-pan) were established and maintained worldwide for a long history. All the pans in the world consist of water body and pan wall, which includes side wall, pan rim and (if any) pan bottom. Since the pan wall will affect E-pan by radiation absorption and heat conduction, once pan wall absorbs and conducts more heat for vaporizing than water body in a pan, observed E-pan dynamics will greatly deviate E-ow causing uncertainties and errors in estimating E-ow. Thus, this study calculated E-pan at 767 meteorological stations in China and quantified the contributions of water body and pan wall on E-pan trends. For China as a whole, E-pan decreased at -3.75 mm/a(2) and increased at 3.68 mm/a(2) during 1960-1993 and 1993-2016, respectively. 84% of E-pan trends were contributed by water body. For 767 stations, E-pan trends of 84 and 96 stations were dominated by pan wall during 1960-1993 and 1993-2016, respectively. Since pan wall contributed more than half of E-pan trends for (similar to)23% of the stations in China, the impacts of pan wall on E-pan dynamics cannot be ignored.
Keywords
Heat Radiation & Absorption; Heat Conduction; Meteorological Stations; Bodies Of Water; Dynamics; Water Diversion; China; Pan Evaporation Dynamics; Pan Wall; Radiation Absorption And Heat Conduction; Trends; Sensitivity; Demand; Model; Absorption; Evaporation; Heat Transfer; Lakes; Surface Water; Uncertainty
Wang, Kaiwen; Liu, Xiaomang; Tian, Wei; Li, Yanzhong; Liang, Kang; Liu, Changming; Li, Yuqi; Yang, Xiaohua. (2019). Pan Coefficient Sensitivity to Environment Variables across China. Journal Of Hydrology, 572, 582 – 591.
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Abstract
Data of open water evaporation (E-ow), such as evaporation of lake and reservoir, have been widely used in hydraulic and hydrological engineering projects, and water resources planning and management in agriculture, forestry and ecology. Because of the low-cost and maneuverability, measuring the evaporation of a pan has been widely regarded as a reliable approach to estimate E-ow through multiplying an appropriate pan coefficient (K-p). K-p is affected by geometry and materials of a pan, and complex surrounding environment variables. However, the relationship between K-p and different environment variables is unknown. Thus, this study chose China D20 pan as an example, used meteorological observations from 767 stations and introduced the latest PenPan model to analyze the sensitivity of K-p to different environment variables. The results show that, the distribution of annual K-p had a strong spatial gradient. For all the stations, annual K-p ranged from 0.31 to 0.89, and decreased gradually from southeast to northwest. The sensitivity analysis shows that for China as a whole, K-p was most sensitive to relative humidity, followed by air temperature, wind speed and sunshine duration. For 767 stations in China, K-p was most sensitive to relative humidity for almost all the stations. For stations north of Yellow River, wind speed and sunshine duration were the next sensitive variables; while for stations south of Yellow River, air temperature was the next sensitive variable. The method introduced in this study could benefit estimating and predicting K-p under future changing environment.
Keywords
Atmospheric Temperature; Hydraulic Engineering; Meteorological Observations; Humidity; Water Supply; Evaporation (meteorology); Sunshine; Lake Management; China; Kp Most Sensitive To Relative Humidity; Open Water Evaporation; Pan Coefficient (kp); Pan Evaporation; Sensitivity Analysis; Reference Evapotranspiration; Reference Crop; Evaporation; Water; Model; Pan Coefficient (k-p); K-p Most Sensitive To Relative Humidity; Air Temperature; Ecology; Forestry; Geometry; Hydrologic Engineering; Lakes; Maneuverability; Meteorological Data; Models; Planning; Prediction; Relative Humidity; Solar Radiation; Wind Speed; Yellow River
Xiang, Wei-qi; Yang, Xiao-hua; Li, Yu-qi. (2021). A Set Pair Analysis Model for Suitability Evaluation of Human Settlement Environment. Thermal Science, 25(3B), 2109 – 2116.
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Abstract
The human settlement environment is a dynamic subsystem where people live and produce in the social system. This paper aims at evaluating comprehensively the suitability state of a given human settlement environment in a certain time and space and its evolutionary trend, the set pair analysis theory and its connection numbers are introduced into the suitability evaluation, and the set of human settlements is established. The set pair analysis model based on partial connection number is used to assess the suitability status and the development trend of human settlements in Guizhou Province from 2014 to 2017. The result shows that the set pair analysis model has the features of convenience, impersonality and good feasibility.
Keywords
Human Ecology; Human Settlements; Number Theory; Social Systems; Guizhou Sheng (china); Human Settlement Environment; Partial Connection Number; Set Pair Analysis; Suitability Evaluation
Urban ecology, simulation modeling, scenario planning, enhancing ecosystem functions in coupled human-natural systems