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This study explores the quality of data produced by Global Precipitation Measurement (GPM) and the potential of GPM for real-time short-term nowcasting using MATLAB and the Short-Term Ensemble Prediction System (STEPS). Precipitation data obtained by rain gauges during the period 2015 to 2017 were used in this comparative analysis. The results show that the quality of GPM precipitation has different degrees efficacies at the national scale, which were revealed at the performance analysis stage of the study. After data quality checking, five representative precipitation events were selected for nowcasting evaluation. The GPM estimated precipitation compared to a 30 min forecast using STEPS precipitation nowcast results, showing that the GPM precipitation data performed well in nowcasting between 0 to 120 min. However, the accuracy and quality of nowcasting precipitation significantly reduced with increased lead time. A major finding from the study is that the quality of precipitation data can be improved through blending processes such as kriging with external drift and the double-kernel smoothing method, which enhances the quality of nowcast over longer lead times.
Kaiyang Wang; Lingrong Kong; Zixin Yang; Prateek Singh; Fangyu Guo; Yunqing Xu; Xiaonan Tang; Jianli Hao. GPM Annual and Daily Precipitation Data for Real-Time Short-Term Nowcasting: A Pilot Study for a Way Forward in Data Assimilation. Water 2021, 13, 1422 .
AMA StyleKaiyang Wang, Lingrong Kong, Zixin Yang, Prateek Singh, Fangyu Guo, Yunqing Xu, Xiaonan Tang, Jianli Hao. GPM Annual and Daily Precipitation Data for Real-Time Short-Term Nowcasting: A Pilot Study for a Way Forward in Data Assimilation. Water. 2021; 13 (10):1422.
Chicago/Turabian StyleKaiyang Wang; Lingrong Kong; Zixin Yang; Prateek Singh; Fangyu Guo; Yunqing Xu; Xiaonan Tang; Jianli Hao. 2021. "GPM Annual and Daily Precipitation Data for Real-Time Short-Term Nowcasting: A Pilot Study for a Way Forward in Data Assimilation." Water 13, no. 10: 1422.
During China’s rapid economic development and urbanization, numerous cases of urban malodorous black river (MBR) have occurred. MBR refers to a polluted urban river that smells bad, is almost black in color, has no aquatic plants or animals, and that consequently causes many social and environmental problems. The Chinese government has sought public participation during the whole process of MBR treatment as part of a comprehensive action plan to improve residents’ satisfaction with their environment. To investigate the influencing factors of public participation and satisfaction, a questionnaire survey was conducted among residential communities close to an MBR. SPSS 22.0 was employed to conduct an analysis of the collected data, using factor analysis, correlation analysis, and linear regression analysis. The results indicate that there is a direct relationship between public satisfaction and the factors of government treatment, public perception and public participation behaviors, such as engagement behavior, supervision behavior, health influence, and compensation measures.
Shiwang Yu; Jianxia Bao; Wen Ding; Xue Chen; Xiaonan Tang; Jianli Hao; Wei Zhang; Prateek Singh. Investigating the Relationship between Public Satisfaction and Public Environmental Participation during Government Treatment of Urban Malodorous Black River in China. Sustainability 2021, 13, 3584 .
AMA StyleShiwang Yu, Jianxia Bao, Wen Ding, Xue Chen, Xiaonan Tang, Jianli Hao, Wei Zhang, Prateek Singh. Investigating the Relationship between Public Satisfaction and Public Environmental Participation during Government Treatment of Urban Malodorous Black River in China. Sustainability. 2021; 13 (6):3584.
Chicago/Turabian StyleShiwang Yu; Jianxia Bao; Wen Ding; Xue Chen; Xiaonan Tang; Jianli Hao; Wei Zhang; Prateek Singh. 2021. "Investigating the Relationship between Public Satisfaction and Public Environmental Participation during Government Treatment of Urban Malodorous Black River in China." Sustainability 13, no. 6: 3584.
Conventional centralized drainage systems are not only expensive, but their mono-function to discharge surface runoff also imposes a negative effect on the local environment while compounding regional watershed dysfunction. Sponge city initiative promoted by the Chinese government is a broader sustainable stormwater management concept that aims to use more nature-based solutions, reduce urban flooding and runoff pollution, and increase rainwater resource usage. As part of decentralized and cost-effective solutions, green infrastructure (GI) is considered in the Sponge City development across China. Although GI has been successfully implemented through a range of small-scale projects, the GI approach has not been adopted widely, which is because the GI approach is micro-scale techniques and the local government is skeptical about the efficiency of GI to mitigate stormwater on a large scale. Although some researchers have explored the effectiveness of GI to reduce stormwater in small catchments, only a limited number of studies have examined the efficacy of GI at the watershed scale. Moreover, there is lack of a system and cross-scale approach in sponge city practices. To understand the effect of GI on the watershed scale, this paper proposed a comprehensive approach using ArcGIS and SWMM platforms to study the spatial configuration and implementation of multi-scale stormwater management. The approach is to apply a three-step sequence of catchments, sub-catchments, and micro-catchments for the urban watershed through designing interconnected network of landscape infrastructure (LI) systems. The design scenarios and performance of LI system-based approach with different combinations and sizes of the sponge facilities were analyzed based on the Old Town district of Hefei City, China. This study demonstrated that the inherent capacity of the landscape can act as the conduit for multifunctional, flexible, localized, and synergistic infrastructural systems, in which cross watershed holds promise to decrease both runoff volumes and peak flows while providing ecosystem services, such as enhancing neighborhood aesthetics and cultural/health benefits through shared public green spaces. Thus, Sponge City Development here as green concepts and techniques for nature-based solutions enhances the function and value of green infrastructure with benefits of ecological, economic and social significances, which presents a new approach for sustainable city making.
Jun Zhai; Jing Ren; Miao Xi; Xiaonan Tang; Yixin Zhang. Multiscale watershed landscape infrastructure: Integrated system design for sponge city development. Urban Forestry & Urban Greening 2021, 60, 127060 .
AMA StyleJun Zhai, Jing Ren, Miao Xi, Xiaonan Tang, Yixin Zhang. Multiscale watershed landscape infrastructure: Integrated system design for sponge city development. Urban Forestry & Urban Greening. 2021; 60 ():127060.
Chicago/Turabian StyleJun Zhai; Jing Ren; Miao Xi; Xiaonan Tang; Yixin Zhang. 2021. "Multiscale watershed landscape infrastructure: Integrated system design for sponge city development." Urban Forestry & Urban Greening 60, no. : 127060.
Vegetation in watercourses can influence different aspects of flow structure, subsequently affecting many processes of flow, such as pollutant transportation, sediment deposition and hydrophyte habitat distribution. Vegetation often occurs on one side of a channel, which requires understanding the effects of partial vegetation on the flow. Although many studies have been done on flows through uniform vegetation, this type of flow is unrealistic, as in natural floodplains, the vegetation in riparian zones is usually non-uniform. There is little study on the hydraulic characteristics of the flow with the co-existence of short and tall vegetation under either emergent or submerged conditions. In this paper, a novel experiment with rigid vegetation of two heights in one side of a channel was conducted to understand flow characteristics such as velocity profile, turbulence intensity, Reynolds stress, and discharge distribution. Experimental results revealed that the velocity is almost constant over the short vegetation height and increases sharply with the depth just above the short vegetation. Similarly, the Reynolds stress had little variation in the short vegetation layer, but started to increase rapidly from the top of the short vegetation to the water surface, which indicates the presence of strong mixing layer near the top of the short vegetation. Additionally, a strong shear layer existed between non-vegetated and vegetated zones, indicating the reduction effect of vegetation on the flow velocity. Furthermore, modifications are needed to properly calculate the hydraulic radius and Manning's coefficient for the flow with double-layered vegetation.
Xiaonan Tang; Hamidreza Rahimi; Yutong Guan; Yuxuan Wang. Hydraulic characteristics of open-channel flow with partially-placed double layer rigid vegetation. Environmental Fluid Mechanics 2021, 21, 317 -342.
AMA StyleXiaonan Tang, Hamidreza Rahimi, Yutong Guan, Yuxuan Wang. Hydraulic characteristics of open-channel flow with partially-placed double layer rigid vegetation. Environmental Fluid Mechanics. 2021; 21 (2):317-342.
Chicago/Turabian StyleXiaonan Tang; Hamidreza Rahimi; Yutong Guan; Yuxuan Wang. 2021. "Hydraulic characteristics of open-channel flow with partially-placed double layer rigid vegetation." Environmental Fluid Mechanics 21, no. 2: 317-342.
Stormwater management is a key issue in line with global problems of urbanization and climate change. Assessing the effectiveness in managing stormwater is crucial to maintain urban resilience to flooding risk. A method based on a stormwater management model (SWMM) was developed for assessing the control of stormwater runoff volume and the percentage removal of suspended solids by implementing a Sponge City strategy. An interdisciplinary approach was adopted incorporating Low Impact Development (LID) with urban green infrastructure and grey infrastructure paradigms in a typical old residential community in Suzhou, China. Sponge facilities for reducing stormwater runoff included bio-retention cells, permeable pavements, grassed pitches, and stormwater gardens. The simulation results of SWMM show that the stormwater pipe system can meet the management standard for storms with a five-year recurrence interval. The volume capture ratio of annual runoff was 91%, which is higher than control target of 80%. The suspended solids reduction rate was 56%, which meets the requirement of planning indicators. Thus, the proposed method of spongy facilities can be used for renovation planning in old residential areas in China. Implementing spongy facilities with a LID strategy for stormwater management can significantly enhance urban water resilience and improve ecosystem services.
Yixin Zhang; Weihan Zhao; Xue Chen; Changhyun Jun; Jianli Hao; Xiaonan Tang; Jun Zhai. Assessment on the Effectiveness of Urban Stormwater Management. Water 2020, 13, 4 .
AMA StyleYixin Zhang, Weihan Zhao, Xue Chen, Changhyun Jun, Jianli Hao, Xiaonan Tang, Jun Zhai. Assessment on the Effectiveness of Urban Stormwater Management. Water. 2020; 13 (1):4.
Chicago/Turabian StyleYixin Zhang; Weihan Zhao; Xue Chen; Changhyun Jun; Jianli Hao; Xiaonan Tang; Jun Zhai. 2020. "Assessment on the Effectiveness of Urban Stormwater Management." Water 13, no. 1: 4.
Stormwater management is a key urban issue in the world, in line with the global issues of urban sprawl and climate change. It is urgent to investigate the effectiveness in managing stormwater with different strategies for maintain urban resilience. A method based on a storm water management model (SWMM) was developed for assessing the control of stormwater runoff volume and the percentage removal of suspended solids by implementing a Sponge City strategy. An interdisciplinary approach was adopted incorporating Low Impact Development (LID) with urban Green Infrastructure and Gray Infrastructure paradigms in a typical old residential community in Suzhou, China. Four types of sponge facilities for reducing stormwater runoff were bio-retention cells, permeable pavements, grassed pitches, and stormwater gardens. The simulation results indicate that the stormwater pipe system can meet the management standard for storms with a five-year recurrence interval. The volume capture ratio of annual runoff is 91% and the reduction rate of suspended solids is 56%. This study demonstrates that Sponge City strategy is an effective approach for managing stormwater, particularly in old and densely populated urban areas. Implementing spongy facilities with a LID strategy for stormwater management can significantly enhance urban water resilience and increase ecosystem services.
Yixin Zhang; Weihan Zhao; Xue Chen; Changhyun Jun; Jianli Hao; Xiaonan Tang; Jun Zhai. Assessment on the Effectiveness of Urban Stormwater Management. 2020, 1 .
AMA StyleYixin Zhang, Weihan Zhao, Xue Chen, Changhyun Jun, Jianli Hao, Xiaonan Tang, Jun Zhai. Assessment on the Effectiveness of Urban Stormwater Management. . 2020; ():1.
Chicago/Turabian StyleYixin Zhang; Weihan Zhao; Xue Chen; Changhyun Jun; Jianli Hao; Xiaonan Tang; Jun Zhai. 2020. "Assessment on the Effectiveness of Urban Stormwater Management." , no. : 1.
Discharge calculations and conveyance estimations in rivers are of prime importance during high flow events. Conventional methods using single global resistance parameters are incapable of assessing discharge with high precision; thus incorporating apparent shear into these methods not only improves the results but also addresses the momentum transfer phenomena over sub-sections. Apparent shear stress modelling for asymmetric channels with different geometric and roughness parameters is found to be monotonic and tedious in linear regression. To improve its accuracy and efficiency, one of the modelling tools is to apply adaptive network-based fuzzy inference system (ANFIS). In this paper, apparent shear stress is trained, modeled and tested for a wide range of asymmetric channels including various experimental and field data. It is found that asymmetrical channels have large positive shear force acting at the vertical imaginary interface between the floodplain and main channel. The positive apparent shear force indicates that the slower floodplain flow retards the faster flow in the main channel. Therefore, considering correct shear stress in the discharge estimation will result in higher accuracy. The application of ANFIS in modelling the output variable of apparent shear stress is done using five geometrical and hydraulic parameters of varying range from small-scale experiments to real field measurements as the input variables. The coefficient of determination (R2) for the modeled apparent shear is 0.96, which is exceptionally high as comparison to past models. Furthermore, comparison of discharge calculation using modeled apparent shear stress and other conventional methods has shown that the results obtained using vertical interface shear stress have higher accuracy.
Prateek Kumar Singh; Xiaonan Tang. Estimation of apparent shear stress of asymmetric compound channels using neuro-fuzzy inference system. Journal of Hydro-environment Research 2020, 29, 96 -108.
AMA StylePrateek Kumar Singh, Xiaonan Tang. Estimation of apparent shear stress of asymmetric compound channels using neuro-fuzzy inference system. Journal of Hydro-environment Research. 2020; 29 ():96-108.
Chicago/Turabian StylePrateek Kumar Singh; Xiaonan Tang. 2020. "Estimation of apparent shear stress of asymmetric compound channels using neuro-fuzzy inference system." Journal of Hydro-environment Research 29, no. : 96-108.
Flow within vegetation characterized by non-uniform roughness density is drawing significant research attention given its relevance to a plethora of applications in eco-hydraulics including river restoration, and flow in wetland and marshes. The focus here is on flume experiments and modeling of the mean longitudinal velocity profile in a two layered cylindrical vegetation system. Layer 1 represents the region close to the channel bottom where the flow experiences maximum drag due to the densely placed vegetation, while layer 2 represents the flow region above the short vegetation characterized by a smaller vegetation density. Considering the aforementioned arrangements, a new analytical model based on Reynolds-averaged closure principles is proposed to describe the vertical distribution of mean streamwise velocity in an open channel with two different vegetation densities. In the proposed model, the one-dimensional steady and planar-homogeneous momentum equation is used where the turbulent eddy viscosity is assumed to be linearly related to the local mean velocity. The proposed analytical model has been calibrated using experiments reported here in which vegetation is represented by using circular plastic cylinders of two different heights. The proposed model is further tested against published experiments with similar arrangements. In total, 22 different experimental conditions with distinct densities, rigidity, and flow depths have been analyzed. The Root Mean Square Error (RMSE) of the velocity comparisons is found to be less than 0.0342 m/s, which is acceptable.
H.R. Rahimi; X. Tang; P. Singh; M. Li; S. Alaghmand. Open channel flow within and above a layered vegetation: Experiments and first-order closure modeling. Advances in Water Resources 2020, 137, 103527 .
AMA StyleH.R. Rahimi, X. Tang, P. Singh, M. Li, S. Alaghmand. Open channel flow within and above a layered vegetation: Experiments and first-order closure modeling. Advances in Water Resources. 2020; 137 ():103527.
Chicago/Turabian StyleH.R. Rahimi; X. Tang; P. Singh; M. Li; S. Alaghmand. 2020. "Open channel flow within and above a layered vegetation: Experiments and first-order closure modeling." Advances in Water Resources 137, no. : 103527.
Accurately predicting flow discharge in a compound river channel becomes increasingly important for flood risk management and river eco-environment design. This paper proposes a new general approach based on the concept of the apparent shear stress at an inclined interface plane between main channel and floodplains. The new approach with a diagonal plane is applied with a wide range of the author's experimental data and the data available in the literature, which include 59 datasets. Among them, 27 are homogenous channels of symmetric channels (22 datasets) and asymmetric channels (5 datasets) whereas 32 are heterogeneously roughened channels of symmetric channels (22 datasets) and asymmetric channels (10 datasets). It was found that the new approach improves the accuracy of discharge compared with the DCM for all datasets. The predicted total discharge for straight homogeneous channels has a mean absolute percentage error (MAPE) of 5%, whereas the MAPE error is about 6.7% for heterogeneously roughened channels. •A general approach of discharge prediction is presented based on apparent shear stress on an inclined interface.•Both zonal and total discharge can be calculated using the proposed method.•The predicted results are compared with 59 sets of experimental data along with the DCM.
Xiaonan Tang. Apparent shear stress-based method on an inclined interface plane for predicting discharge in straight compound channels. MethodsX 2019, 6, 1323 -1329.
AMA StyleXiaonan Tang. Apparent shear stress-based method on an inclined interface plane for predicting discharge in straight compound channels. MethodsX. 2019; 6 ():1323-1329.
Chicago/Turabian StyleXiaonan Tang. 2019. "Apparent shear stress-based method on an inclined interface plane for predicting discharge in straight compound channels." MethodsX 6, no. : 1323-1329.
Accurately predicting flow discharge in a compound river channel becomes increasingly important when in river eco-environment design and flood risk management, in which the conventional methods, such as divided channel method (DCM) and single channel method, do not meet precision requirement. In the present paper, a new approach is proposed to improve the prediction of flow based on the concept of the apparent shear stress at the diagonal interface between main channel and floodplains. The new approach is compared with a wide range of the author's experimental data and the data available in the literature. The 27 datasets used in this study cover homogenous symmetric channels (22 datasets) and asymmetric channels (5 datasets), which have various width ratios [channel total width (B) at bankfull / main channel bottom (b) = 1.5 ~ 15.8] and bed slopes (So = 2.6×10-4 ~2.5×10-3). It was found that the new approach can significantly improve the accuracy of flow prediction compared with the conventional DCM for all the datasets, particularly for relatively low flow depths of floodplain (e.g. Dr < 0.15) where the flow discharge was very difficult to predict correctly. The new approach predicts the total discharge well for straight homogeneously symmetric and asymmetric channels, within a mean absolute percentage error (MAPE) of 5%. Furthermore, compared with the DCM, the new approach can also have a better prediction of zonal discharge percentage and it has less variation of discharge prediction error over the flow depth.
Xiaonan Tang. A new apparent shear stress-based approach for predicting discharge in uniformly roughened straight compound channels. Flow Measurement and Instrumentation 2019, 65, 280 -287.
AMA StyleXiaonan Tang. A new apparent shear stress-based approach for predicting discharge in uniformly roughened straight compound channels. Flow Measurement and Instrumentation. 2019; 65 ():280-287.
Chicago/Turabian StyleXiaonan Tang. 2019. "A new apparent shear stress-based approach for predicting discharge in uniformly roughened straight compound channels." Flow Measurement and Instrumentation 65, no. : 280-287.
This paper presents a descriptive analysis of the double layer vegetation flow and the application of different empirical models for velocity distribution in vegetation flow. To establish the models, extensive experiments are carried out using plastic dowels of differential heights, configurations and densities. The previous models based on empiricism and momentum balance are applied here and found to work satisfactorily. However, it is found out that the boundary conditions play a significant role to capture inflection over vegetation level. Furthermore, the most important factor for capturing the inflection above zero plane displacement is to understand the intermediate boundary conditions and their superposition rather than extremum conditions. Therefore a new model for mixing length over the short vegetation height has been suggested. The results from the velocity distributions, turbulence intensity and vorticity of the experimental data are used to derive a new relationship for mixing length under certain assumptions. For establishing the proposed model other researchers’ data are considered and finally corroborated for the validation set, which suggests that the proposed model agrees reasonably well with the measured data.
P. Singh; H. R. Rahimi; X. Tang. Parameterization of the modeling variables in velocity analytical solutions of open-channel flows with double-layered vegetation. Environmental Fluid Mechanics 2019, 19, 765 -784.
AMA StyleP. Singh, H. R. Rahimi, X. Tang. Parameterization of the modeling variables in velocity analytical solutions of open-channel flows with double-layered vegetation. Environmental Fluid Mechanics. 2019; 19 (3):765-784.
Chicago/Turabian StyleP. Singh; H. R. Rahimi; X. Tang. 2019. "Parameterization of the modeling variables in velocity analytical solutions of open-channel flows with double-layered vegetation." Environmental Fluid Mechanics 19, no. 3: 765-784.
In open‐channel flows with submerged vegetation, the vertical velocity profile can often be described by two layers: the vegetation layer in the lower region and the surface layer in the upper non‐vegetated region. In this paper, a new mixing‐length scale of eddy is proposed for predicting the vertical velocity profile of flow in an open‐channel with submerged rigid vegetation. The analytical model of velocity profile is based on the momentum equation of flow where the turbulent eddy viscosity is assumed to have a linear relationship with the local velocity. The proposed model was tested against different datasets from the literature. The 22 datasets used cover a range of submergence [flow depth (H)/vegetation height (h) = 1.25 ~ 3.38], different vegetation densities of ah = 0.11 ~ 1.85 (a defined as the frontal area of the vegetation per unit volume) and bed slopes (So = 1.8 × 10−6 ~4.0 × 10−3). This study showed that the proposed model can predict the velocity profiles well against all datasets, and that the mixing length scale of eddies (λ) is well related with both vegetation height (h) and flow depth of surface layer (i.e. the height of non‐vegetation layer, H–h). Close examination of λ in the proposed model showed that when λ = 0.03, the model predicts vertical velocity profiles well for all datasets used except for very shallow submergence (i.e. H/h < 1.5).
Xiaonan Tang. A mixing‐length‐scale‐based analytical model for predicting velocity profiles of open‐channel flows with submerged rigid vegetation. Water and Environment Journal 2018, 33, 610 -619.
AMA StyleXiaonan Tang. A mixing‐length‐scale‐based analytical model for predicting velocity profiles of open‐channel flows with submerged rigid vegetation. Water and Environment Journal. 2018; 33 (4):610-619.
Chicago/Turabian StyleXiaonan Tang. 2018. "A mixing‐length‐scale‐based analytical model for predicting velocity profiles of open‐channel flows with submerged rigid vegetation." Water and Environment Journal 33, no. 4: 610-619.