One of the most serious droughts in last century occurred in eastern Sichuan Basin in the summer of 2006(hereinafter called the Drought).The response of Moderate Resolution Imaging Spectroradiometer(MODIS,boarding on ...One of the most serious droughts in last century occurred in eastern Sichuan Basin in the summer of 2006(hereinafter called the Drought).The response of Moderate Resolution Imaging Spectroradiometer(MODIS,boarding on NASA satellites of Terra and Aqua)to the Drought was analyzed in order to reach one practicable monitoring solution for regional soil moisture.Temporal process and spatial extension of the Drought were firstly estimated with ground meteorological and hydrological observations.Then,for the whole region of Sichuan and Chongqing,the remotely sensed Normalized Difference Water In-dex(NDWI)for the summers of 2001―2006 were calculated based on 8-day composite MODIS products,which were further used to construct a new water index(Normalized Difference Water Deviation Index,NDWDI)to examine the sensitivity of remote sensing in the Drought.The study showed that the NDWDI is more sensitive to regional drought than other absolute-soil-moisture-based indices.With the new index,the study extracted the spatial-temporal characteristics of the 2006 Drought,and explored its developing and withdrawing processes,which agreed with related statistics.Compared with ground method of drought observation,the NDWDI-based remote sensing solution of this paper is more pref-erable and practicable in that the local soil properties of water consumption and supply are implicitly taken into account,and the spatial representativity limit of ground observation is circumvented to a degree as satellite remotely senses the earth surface in a way of two-dimensional pixel matrix.So,the NDWDI-based method can be used to monitor regional soil water stress situation more practically and efficiently.展开更多
Closing a single nozzle or multiple nozzles for a temporary casting operation(fewer strands casting)was common in a tundish due to insufficient molten steel or equipment failure.However,nozzle clogging usually happens...Closing a single nozzle or multiple nozzles for a temporary casting operation(fewer strands casting)was common in a tundish due to insufficient molten steel or equipment failure.However,nozzle clogging usually happens under the situation of fewer strands casting.Hence,a temperature deviation index was introduced to characterize the temperature stratification of molten steel for a large capacity tundish,and a new calculation method of residence time curve was used to describe the different flow types of molten steel at each outlet.Based on hydraulics experiment and numerical simulation,important parameters of present case and modified case were compared.Under the situation of fewer strands casting,the proportion of internal-recycle flow after modification decreased from 30.68%to 24.55%;the standard deviation of the response time reduced from 27.59 to 13.16,and the interquartile range of temperature deviation index changed from 0.89 to 0.27.展开更多
Sampling frequency is an important factor to be considered during the design of a water monitoring network,and the cost-effective selection of possible ways and means for the optimization of sampling frequency is stil...Sampling frequency is an important factor to be considered during the design of a water monitoring network,and the cost-effective selection of possible ways and means for the optimization of sampling frequency is still needed.This paper introduces water pollution index deviation ratio comparison(WPI DRC),a procedure for the optimization of sampling frequency for a routine river water quality monitoring system.Sampling frequency optimized using WPI DRC at monitoring station X5 in the mainstream of Xiangjiang River is compared with that established using the traditional Statistical Algorithm method.The result of comparison indicates that WPI DRC is more feasible than the traditional one.And then,the sampling frequencies for other 16 monitoring stations also have been optimized,and the results show the sampling frequencies of all the stations except that X4 are reduced,and there is no unacceptable difference between water quality evaluation results at 17 stations before and after the optimization.Therefore,it is concluded that WPI DRC is an effective optimization process with operable results,which can be used to fulfill the requirement of practical monitoring work.展开更多
基金the National Natural Science Foundation of China(Grant No.40705037)Commonweal Fund of Changjiang Scientific Research Institute(Grant No.YWF0713/ZY05)
文摘One of the most serious droughts in last century occurred in eastern Sichuan Basin in the summer of 2006(hereinafter called the Drought).The response of Moderate Resolution Imaging Spectroradiometer(MODIS,boarding on NASA satellites of Terra and Aqua)to the Drought was analyzed in order to reach one practicable monitoring solution for regional soil moisture.Temporal process and spatial extension of the Drought were firstly estimated with ground meteorological and hydrological observations.Then,for the whole region of Sichuan and Chongqing,the remotely sensed Normalized Difference Water In-dex(NDWI)for the summers of 2001―2006 were calculated based on 8-day composite MODIS products,which were further used to construct a new water index(Normalized Difference Water Deviation Index,NDWDI)to examine the sensitivity of remote sensing in the Drought.The study showed that the NDWDI is more sensitive to regional drought than other absolute-soil-moisture-based indices.With the new index,the study extracted the spatial-temporal characteristics of the 2006 Drought,and explored its developing and withdrawing processes,which agreed with related statistics.Compared with ground method of drought observation,the NDWDI-based remote sensing solution of this paper is more pref-erable and practicable in that the local soil properties of water consumption and supply are implicitly taken into account,and the spatial representativity limit of ground observation is circumvented to a degree as satellite remotely senses the earth surface in a way of two-dimensional pixel matrix.So,the NDWDI-based method can be used to monitor regional soil water stress situation more practically and efficiently.
基金the National Natural Science Foundation of China(Grant No.51774031).
文摘Closing a single nozzle or multiple nozzles for a temporary casting operation(fewer strands casting)was common in a tundish due to insufficient molten steel or equipment failure.However,nozzle clogging usually happens under the situation of fewer strands casting.Hence,a temperature deviation index was introduced to characterize the temperature stratification of molten steel for a large capacity tundish,and a new calculation method of residence time curve was used to describe the different flow types of molten steel at each outlet.Based on hydraulics experiment and numerical simulation,important parameters of present case and modified case were compared.Under the situation of fewer strands casting,the proportion of internal-recycle flow after modification decreased from 30.68%to 24.55%;the standard deviation of the response time reduced from 27.59 to 13.16,and the interquartile range of temperature deviation index changed from 0.89 to 0.27.
基金the funding from the National Water Pollution Control and Management Technology Major Projects of China(2012ZX07503-002)the Special Research Funding for the Public Benefits sponsored by Ministry of Environmental Protection of PRC(201309067)
文摘Sampling frequency is an important factor to be considered during the design of a water monitoring network,and the cost-effective selection of possible ways and means for the optimization of sampling frequency is still needed.This paper introduces water pollution index deviation ratio comparison(WPI DRC),a procedure for the optimization of sampling frequency for a routine river water quality monitoring system.Sampling frequency optimized using WPI DRC at monitoring station X5 in the mainstream of Xiangjiang River is compared with that established using the traditional Statistical Algorithm method.The result of comparison indicates that WPI DRC is more feasible than the traditional one.And then,the sampling frequencies for other 16 monitoring stations also have been optimized,and the results show the sampling frequencies of all the stations except that X4 are reduced,and there is no unacceptable difference between water quality evaluation results at 17 stations before and after the optimization.Therefore,it is concluded that WPI DRC is an effective optimization process with operable results,which can be used to fulfill the requirement of practical monitoring work.
