As a main component in water balance,evapotranspiration(ET)is of great importance for water saving,especially in arid and semi-arid areas.In this study,the FAO(Food and Agriculture Organization)Penman-Monteith model w...As a main component in water balance,evapotranspiration(ET)is of great importance for water saving,especially in arid and semi-arid areas.In this study,the FAO(Food and Agriculture Organization)Penman-Monteith model was used to estimate the magnitude and temporal dynamics of reference evapotranspiration(ET0)in 2014 in subalpine meadows of the Qilian Mountains,Northwest China.Meanwhile,actual ET(ETc)was also investigated by the eddy covariance(EC)system.Results indicated that ETc estimated by the EC System was 583 mm,lower than ET0(923 mm)estimated by the FAO Penman-Monteith model in 2014.Moreover,ET0 began to increase in March and reached the peak value in August and then declined in September,however,ETc began to increase from April and reached the peak value in July,and then declined in August.Total ETc and ET0 values during the growing season(from May to September)were 441 and 666 mm,respectively,which accounted for 75.73%of annual cumulative ETc and 72.34%of annual cumulative ET0,respectively.A crop coefficient(kc)was also estimated for calculating the ETc,and average value of kc during the growing season was 0.81(ranging from 0.45 to 1.16).Air temperature(Ta),wind speed(u),net radiation(Rn)and soil temperature(Ts)at the depth of 5 cm and aboveground biomass were critical factors for affecting kc,furthermore,a daily empirical kc equation including these main driving factors was developed.Our result demonstrated that the ETc value estimated by the data of kc and ET0 was validated and consistent with the growing season data in 2015 and 2016.展开更多
There is a need to develop safe and effective downstream passage for diadromous anguillid eels on large rivers,where the combination of physical screening and bypass structures that is used to protect eel on smaller r...There is a need to develop safe and effective downstream passage for diadromous anguillid eels on large rivers,where the combination of physical screening and bypass structures that is used to protect eel on smaller rivers is infeasible.The Eel Passage Research Center was established in 2013 to address the challenge of providing safe passage for out-migrating silver-stage American eel(Anguilla rostrata)on the St.Lawrence River,the outflow of the Laurentian Great Lakes,which is spanned by two large,mainstem hydroelectric generating stations.The Center’s goal is to develop the technology to behaviorally guide eel to a collection point for capture and transfer around the two generating stations.To achieve this goal,three parallel initiatives were undertaken;1)research into behavioral guidance techniques suitable for guiding out-migrating eel on large,high flow rivers,2)the evaluation of sonar technologies for detection of eel,necessary for assessing in situ guidance,and 3)the commissioning of literature reviews for the most promising guidance technologies.A number of behavioral guidance stimuli,including electricity,flow,sound and electromagnetic fields were examined in laboratory and flume settings for their utility in guiding out-migrating silver-stage eel.Of the techniques examined,only sound showed any promise for guidance.Three sonar technologies(Simrad 120 kHz EK60 echosounder,Sound Metrics ARIS Explorer 1800 sonar,and the Kongsberg Mesotech 500 kHz M3 multi-mode multibeam sonar)were evaluated to determine if existing acoustic technologies could be used to estimate the relative abundance and distribution of out-migrating silver-phase American eel in the St.Lawrence River.Only the ARIS unit could successfully identify eel targets,and only over a short(<15 m)range.The immense volume of sonar data accumulated over a portion of a single outmigration season contributed to the successful development of machine learning tools to automate the identification of American eel targets.Based on previous research on the St.Lawrence River identifying light as a promising deterrent,and the potential for sound as a deterrent in this study,full literature reviews were commissioned for these two stimuli.Lessons learned to date have resulted in the design of a subscale,prototype guidance structure that is expected to be deployed in 2022.展开更多
基金supported by the National Natural Science Foundation of China (41571051, 91425301)
文摘As a main component in water balance,evapotranspiration(ET)is of great importance for water saving,especially in arid and semi-arid areas.In this study,the FAO(Food and Agriculture Organization)Penman-Monteith model was used to estimate the magnitude and temporal dynamics of reference evapotranspiration(ET0)in 2014 in subalpine meadows of the Qilian Mountains,Northwest China.Meanwhile,actual ET(ETc)was also investigated by the eddy covariance(EC)system.Results indicated that ETc estimated by the EC System was 583 mm,lower than ET0(923 mm)estimated by the FAO Penman-Monteith model in 2014.Moreover,ET0 began to increase in March and reached the peak value in August and then declined in September,however,ETc began to increase from April and reached the peak value in July,and then declined in August.Total ETc and ET0 values during the growing season(from May to September)were 441 and 666 mm,respectively,which accounted for 75.73%of annual cumulative ETc and 72.34%of annual cumulative ET0,respectively.A crop coefficient(kc)was also estimated for calculating the ETc,and average value of kc during the growing season was 0.81(ranging from 0.45 to 1.16).Air temperature(Ta),wind speed(u),net radiation(Rn)and soil temperature(Ts)at the depth of 5 cm and aboveground biomass were critical factors for affecting kc,furthermore,a daily empirical kc equation including these main driving factors was developed.Our result demonstrated that the ETc value estimated by the data of kc and ET0 was validated and consistent with the growing season data in 2015 and 2016.
基金by Natural Sciences and Engineering Research Council of Canada Discovery grants to Q.L.Dang(Project No.203198-2013-RGPIN)Lakehead University Graduate Assistantships to J.Marfo.
基金The research conducted by the EPRC has been funded by the Fish Enhancement,Mitigation,and Research Fund,administered by the U.S.Fish and Wildlife ServiceHydro-Qu´ebec and Ontario Power Generation.Additional funding was received from Duke Energy and the Electric Power Research Institute.
文摘There is a need to develop safe and effective downstream passage for diadromous anguillid eels on large rivers,where the combination of physical screening and bypass structures that is used to protect eel on smaller rivers is infeasible.The Eel Passage Research Center was established in 2013 to address the challenge of providing safe passage for out-migrating silver-stage American eel(Anguilla rostrata)on the St.Lawrence River,the outflow of the Laurentian Great Lakes,which is spanned by two large,mainstem hydroelectric generating stations.The Center’s goal is to develop the technology to behaviorally guide eel to a collection point for capture and transfer around the two generating stations.To achieve this goal,three parallel initiatives were undertaken;1)research into behavioral guidance techniques suitable for guiding out-migrating eel on large,high flow rivers,2)the evaluation of sonar technologies for detection of eel,necessary for assessing in situ guidance,and 3)the commissioning of literature reviews for the most promising guidance technologies.A number of behavioral guidance stimuli,including electricity,flow,sound and electromagnetic fields were examined in laboratory and flume settings for their utility in guiding out-migrating silver-stage eel.Of the techniques examined,only sound showed any promise for guidance.Three sonar technologies(Simrad 120 kHz EK60 echosounder,Sound Metrics ARIS Explorer 1800 sonar,and the Kongsberg Mesotech 500 kHz M3 multi-mode multibeam sonar)were evaluated to determine if existing acoustic technologies could be used to estimate the relative abundance and distribution of out-migrating silver-phase American eel in the St.Lawrence River.Only the ARIS unit could successfully identify eel targets,and only over a short(<15 m)range.The immense volume of sonar data accumulated over a portion of a single outmigration season contributed to the successful development of machine learning tools to automate the identification of American eel targets.Based on previous research on the St.Lawrence River identifying light as a promising deterrent,and the potential for sound as a deterrent in this study,full literature reviews were commissioned for these two stimuli.Lessons learned to date have resulted in the design of a subscale,prototype guidance structure that is expected to be deployed in 2022.
