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Shallow sub-lakes are essential for sustaining the successful wintering of waterbirds in Poyang Lake,China

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Avian Research 2024年第2期15卷 219-228页

作者： Mengjie Lu Zhen Zhang Peng Chen Changxin Xu Bin Gao Luzhang Ruan School of Life Sciences Nanchang UniversityNanchang330031China Jiangxi Province Key Laboratory of watershed Ecosystem Change and Biodiversity Center for Watershed EcologyInstitute of Life Science and School of Life SciencesNanchang UniversityNanchang330031China

For migratory waterbirds,the quality of wintering habitat is related to spring migration and successful breeding in the next year.The availability of food resources in the habitat is critical and varies within water levels.Although the water-level fluctuations in Poyang Lake have been extremely variable interannually in recent years,the wintering waterbird populations have remained relatively stable.Hence,the mechanism of maintaining the stability is worth exploring.This study aimed to compare the distribution of vegetation and herbivorous wa-terbirds in 2015-2016 and 2016-2017,focusing on three shallow sub-lakes and one main lake are.The results showed that the emergence of tubers and the growth of Carex spp.provided a continuous food supply and habitat for wintering waterbirds with a gradual decline in the water level.Shallow sub-lakes supported almost all of the tuber-eating waterbirds(1.42-1.62×10^(5))and most geese(1.34-1.53×10^(6)).However,the main lake area,covered with Persicaria hydropiper,did not provide adequate and accessible food.This resulted in almost no distribution of tuber-eating waterbirds,with only a few geese congregating in early winter.Our results demonstrated that the shallow sub-lakes under human control provided a different environment from the main lake and are key to sustaining the successful wintering of hundreds of thousands of migratory waterbirds in Poyang Lake.Therefore,we recommend refining the anthropogenic management of the shallow sub-lakes to regulate the water level to ensure the carrying capacity of Poyang Lake.

关键词： Anthropogenic management Carrying capacity Seasonal lake water level Wintering habitat

Reconstructing Centennial-Scale water level of Large Pan-Arctic Lakes Using Machine Learning Methods

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Journal of Earth Science 2023年第4期34卷 1218-1230页

作者： Xinge Liang Chunqiao Song Kai Liu Tan Chen Chenyu Fan Key Laboratory of watershed Geographic Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China College of Surveying and Geotechnical Engineering Henan Polytechnic UniversityJiaozuo 454000China University of Chinese Academy of Sciences Beijing 100049China

The pan-Arctic region has the largest number of lakes in the world,which is rather sensitive to changing climate.It is urgently needed to understand how these lakes were changing in the long term.However,there are few lakes with long-term historical monitoring of water level,understanding the hydrologic changes of pan-Arctic lakes over the past century requires the data reconstruction by state-of-art techniques.This study used machine learning algorithms to reconstruct the water level of pan-Arctic lakes on a centennial scale.It further investigated their relationship with long-term hydrological and climatic variables.Comparison of the reconstructed results by four different machine learning models shows that the extreme gradient boosting tree(XGBoost) is better than other three models.Overall,the centennial-scale reconstruction using the XGBoost model performs best for most study lakes.Based on the reconstructed results,we can observe that water level changes of several North American lakes are correlated with potential evapotranspiration,followed by precipitation,while the Eurasian lakes are more strongly associated with temperature and wet day frequency.The water level dynamics of pan-Arctic lakes could be largely attributed to Arctic Oscillation and Atlantic Multidecadal Oscillation.This study is expected to advance our understanding of the pan-Arctic lake water level changes in the past century and to provide a feasible method for reconstructing the regional lake water level in the long term.

关键词： machine learning water level pan-Arctic lake.

water level Deviation Analysis of levels Between Two Sides of the Boiler Drum

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International Journal of Automation and computing 2016年第2期13卷 142-150页

作者： Fei Xia Ya-Lei Quan Hao Zhang Dao-Gang Peng School of Electronic and Information Tongji UniversityShanghai 201804China College of Automation Engineering Shanghai University of Electric PowerShanghai 200090China Shanghai Key Laboratory of Power Station Automation Technology Shanghai 200090China

It is always quite difficult to accurately measure boiler drum water level in power plant. Though the effect of false measurement of water level can be reduced with some devices, the effect of deviation of boiler drum water level to the monitoring and alarm system, even to the control of drum water level, and so on, cannot be surmounted. Because of these reasons, the accurate water level alarm signal cannot be provided and the water level control measures cannot be applied. In order to solve this problem, a water level deviation analysis method is presented for analyzing boiler drum water level. Based on the analysis of boiler drum water level related running parameters, the relational model of water level deviation under different working conditions and its parameters is constructed. By analyzing this model, the specific impacts of the main factors can be fixed. Thus the drum water level deviation can be reduced by adjusting running parameters without changing unit load. And then the measurement of drum water level can be more accurate only if power plants have accurate measuring devices. Therefore, the boiler drum water level can be more accurately monitored and controlled. So, this innovation is important in ensuring the safe running of power plant.

关键词： Boiler drum water level deviation analysis measurement safe running

water-level based discrete integrated dynamic control to regulate the flow for sewer-WWTP operation

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Frontiers of Environmental Science & Engineering 2020年第3期14卷 103-111页

作者： Zhengsheng Lu Moran Wang Mingkai Zhang Ji Li Ying Xu Hanchang Shi Yanchen Liu Xia Huang State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China School of Environment and Civil Engineering Jiangnan UniversityWuxi 214122China Wuxi water Group Co.Ltd. Wuxi 214031China

This study aims to propose a multi-point integrated real-time control method based on discrete dynamic water level variations,which can be realized only based on the programmable logic controller(PLC)system without using a complex mathematical model.A discretized water level control model was developed to conduct the real-time control based on data-automation.It combines the upstream pumping stations and the downstream influent pumping systems of wastewater treatment plant(WWTP).The discretized water level control method can regulate dynamic wastewater pumping flow of pumps following the dynamic water level variation in the sewer system.This control method has been successfully applied in practical integrated operations of sewer-WWTP following the sensitive flow disturbances of the sewer system.The operational results showed that the control method could provide a more stabilized regulate pumping flow for treatment process;it can also reduce the occurrence risk of combined sewer overflow(CSO)during heavy rainfall events by increasing transport capacity of pumping station and influent flow in WWTP,which takes full advantage of storage space in the sewer system.

关键词： Sewer system Integrated control Discrete control water level

Influence of river-lake isolation on the water level variations of Caizi Lake, lower reach of the Yangtze River

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Journal of Geographical Sciences 2021年第4期31卷 551-564页

作者： AN Lesheng LIAO Kaihua ZHU Lei ZHOU Baohua School of Resources and Environment Anqing Normal UniversityAnqing 246133AnhuiChina Key Laboratory of watershed Geographic Sciences Nanjing Institute of Geography and LimnologyCASNanjing 210008China

In order to explore the water level variations of Caizi Lake under river-lake isolation,the monthly water level of the Chefuling station in Caizi Lake from 1989 to 2018 and the daily water level,rainfall and flow of local hydrological stations in 2018 were analyzed by using the Mann-Kendall trend test and wavelet analysis.Results showed that the difference of the average water level of Caizi Lake between the flood and dry seasons was 3.34 m,with a multi-year average water level of 10.42 m above sea level.The first and second main periods of the water level of Caizi Lake were 128 and 18 months,respectively,with 4 and 29"up-down"cycles,respectively.From 2018,the next 3-4 years were likely to be the low water level period.The water level of Caizi Lake was significantly correlated with that of the Anqing hydrological station of the Yangtze River(r=0.824,Pwater Diversion Project(YHWD),the hydrological regime change of Caizi Lake and its eco-environmental effect needed long-term monitoring and research.

关键词： water level hydrological regime river-lake isolation wavelet analysis Caizi Lake

ICESat/GLAS-derived changes in the water level of Hulun Lake, Inner Mongolia, from 2003 to 2009

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Frontiers of Earth Science 2018年第2期12卷 420-430页

作者： Chunlan LI Jun WANG Richa HU Shan YIN Yuhai BAO Yuwei LI Key Laboratory of Geographic Information Science (Ministry of Education) East China Normal University Shanghai 200241 China School of Geographic Sciences East China Normal University Shanghai 200241 China College of Geographical Sciences Inner Mongolia Normal University Huhhot 010022 China Key Laboratory of Remote Sensing and Geographic Information System Inner Mongolia Normal University Huhhot 010022 China

Hulun Lake is the largest freshwater lake in northern Inner Mongolia and even minor changes in its level may have major effects on the ecology of the lake and the surrounding area. In this study, we used high-precision elevation data for the interval from 2003–2009 measured by the Geoscience Laser Altimetry System (GLAS) on board the Ice, Cloud, and land Elevation Satellite (ICESat) to assess annual and seasonal water level variations of Hulun Lake. The altimetry data of 32 satellite tracks were processed using the RANdom SAmple Consensus algorithm (RANSAC) to eliminate elevation outliers, and subsequently the Normalized Difference water Index (NDWI) was used to delineate the area of the lake. From 2003–2009, the shoreline of Hulun Lake retreated westwards, which was especially notable in the southern part of the lake. There was only a small decrease in water level, from 530.72 m to 529.22 m during 2003–2009, an average rate of 0.08 m/yr. The area of the lake decreased at a rate of 49.52 km2/yr, which was mainly the result of the shallow bathymetry in the southern part of the basin. The decrease in area was initially rapid, then much slower, and finally rapid again. Generally, the lake extent and water level decreased due to higher temperatures, intense evaporation, low precipitation, and decreasing runoff. And their fluctuations were caused by a decrease in intraannual temperature, evaporation, and a slight increase in precipitation. Overall, a combination of factors related to climate change were responsible for the variations of the water level of Hulun Lake during the study interval. The results improve our understanding of the impact of climate change on Hulun Lake and may facilitate the formulation of response strategies.

关键词： ICESat/GLAS altimetry water level Hulun Lake arid area climate change

Numerical simulation of the impacts of water level variation on water age in Dahuofang Reservoir

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Frontiers of Earth Science 2015年第2期9卷 209-224页

作者： Xinwen LI Yongming SHEN State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China

The transport timescales were investigated in response to water level variation under different constant flow rates in Dahuofang Reservoir. The concept of water age was applied to quantifY the transport timescales. A three-dimensional hydrodynamic model was developed based on the Environmental Fluid Dynamics Code （EFDC）. The model was calibrated for water surface elevation and temperature profiles from April 1, 2008 to October 31, 2008. Comparisons of observed and modeled data showed that the model reproduced the water level fluctuation and thermal stratification during warm season and vertical mixing during cold season fairly well. The calibrated model was then applied to investigate the response of water age to water level changes in Dahuofang Reservoir. Model results showed that water age increases from confluence toward dam zone. In the vertical direction, the water age is relatively uniform at upstream and stratifies further downstream, with a larger value at bottom layer than at surface layer. Comparisons demonstrated that water level variation has a significant impact on transport timescales in the reservoir. The impact of water level drawdown on water age is stronger at bottom layer than at surface layer. Under high flow conditions, the water age decreases 0-20days at surface layer and 15-25 days at bottom layer. Under mean flow conditions, the water age decreases 20-30 days at surface layer and 30-50 days at bottom layer. Furthermore, the impact is minor in the upstream and increases further downstream. The vertical stratification of water age weakens as the water level decreases. This study provides a numerical tool to quantify the transport timescale in Dahuofang Reservoir and supports adaptive management of regional water resources by local authorities.

关键词： water age EFDC Dahuofang Reservoir,numerical simulation water level

Mean water level setup/setdown in the inlet-lagoon system induced by tidal action—a case study of Xincun Inlet,Hainan Island in China

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Acta Oceanologica Sinica 2008年第5期27卷 63-80页

作者： GONG Wenping SHEN Jian WANG Daoru Virginia Institute of Marine Science College of William and Mary Gloucester Point VA 23062USA Hainan Marine Development Planning and Design Research Institute Haikou 570125 China

With the tides propagating from the open sea to the lagoon, the mean water level （MWL） in the inlet and lagoon becomes different from that at the open sea, and a setup/setdown is generated. The change of MWL （setup/setdown） in the system imposes a great impact on regulating the development of tidal marshes, on determining the long-term water level for harbor maintenance, on the planning for the water front development with the flood control for the possible inundation, and on the interpretation of the historical sea level change when using tidal marsh peat deposits in the lagoon as the indicator for open sea＇ s sea level. In this case study on the mechanisms which control the setup/setdown in Xincun Inlet, Hainan in China, the 2-D barotropic mode of Eulerian - Lagrangian CIRCulation （ELCIRC） model was utilized. After model calibration and verification, a series of numerical experiments were conducted to examine the effects of bottom friction and advection terms, wetting and drying of intertidal areas, bathymetry and boundary conditions on the setup/setdown in the system. The modeling results show that setup occurs over the inlet and lagoon areas with an order of one tenth of the tide range at the entrance. The larger the bottom friction is, a larger setup is generated. Without the advection term, the setup is reduced clue to a decrease of water level gradient to compensate for the disappearance of the advection term. Even without overtides, a setup can still be developed in the system. Sea level rise and dredging in the inlet and tidal channel can cause a decrease of setup in the system, whereas shoaling of the system can increase the setup. The uniqueness of the Xincun Inlet with respect to MWL change is that there is no evident setdown in the inlet, which can be attributed to the complex geometry and bathymetry associated with the inlet system.

关键词： tidal inlet water level setup/setdown ELCIRC Hainan Island

Effects of water level alteration on carbon cycling in peatlands

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Ecosystem Health and Sustainability 2020年第1期6卷 199-227,198页

作者： Yehui Zhong Ming Jiang Beth A.Middleton Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchunJilinPR China University of Chinese Academy of Sciences BeijingPR China Jilin Provincial Joint Key Laboratory of Changbai Mountain Wetland and Ecology ChangchunJilinPR China U.S.Geological Survey Wetlands and Aquatic Research CenterLafayetteLAUSA

Globally,peatlands play an important role in the carbon(C)cycle.High water level is a key factor in maintaining C storage in peatlands,but water levels are vulnerable to climate change and anthropogenic disturbance.This review examines literature related to the effects of water level alteration on C cycling in peatlands to summarize new ideas and uncertainties emerging in this field.Peatland ecosystems maintain their function by altering plant community structure to adapt to changing water levels.Regarding primary production,woody plants are more productive in unflooded,well-aerated conditions,while Sphagnum mosses are more productive in wetter conditions.The responses of sedges to water level alteration are species-specific.While peat decomposition is faster in unflooded,well aerated conditions,increased plant production may counteract the C loss induced by increased ecosystem respiration(ER)for a period of time.In contrast,rising water table maintains anaerobic conditions and enhances the role of the peatland as a C sink.Nevertheless,changes in DOC flux during water level fluctuation is complicated and depends on the interactions of flooding with environment.Notably,vegetation also plays a role in C flux but particular species vary in their ability to sequester and transport C.Bog ecosystems have a greater resilience to water level alteration than fens,due to differences in biogeochemical responses to hydrology.The full understanding of the role of peatlands in global C cycling deserves much more study due to uncertainties of vegetation feedbacks,peat-water interactions,microbial mediation of vegetation,wildfire,and functional responses after hydrologic restoration.

关键词： Peatlands carbon cycling climate change anthropogenic disturbance water level