饮用水水源地水质演变趋势研究对水源地的保护具有重要意义。以中国某城市6个市级水源地为研究对象,采用水质指数法进行水质评价,在此基础上结合Pettitt Mann Whitney变异点分析法、Mann-Kendall趋势检验法和线性回归法,深入分析了各水...饮用水水源地水质演变趋势研究对水源地的保护具有重要意义。以中国某城市6个市级水源地为研究对象,采用水质指数法进行水质评价,在此基础上结合Pettitt Mann Whitney变异点分析法、Mann-Kendall趋势检验法和线性回归法,深入分析了各水源地水质突变时间及演变趋势,并结合该市近年来的管理政策分析了水质变化的原因。2020年-2022年各水源地水质现状整体较好,4个水源地水质评价结果为优良,其余为良好。变异点和演变趋势分析结果表明,各水源地均存在突变时间,水质指数突变时间主要集中在2021年2月-2022年4月,突变后2个水源地水质变差,其余水源地水质变好,仅1个水源地变异显著。该市水源地整体上2022年水质状况优于往年,主要得益于流域整体水环境质量改善和水源地特殊保护的加强。展开更多
In the last decade,North Africa has witnessed significant population growth,particularly those bordering the Mediterranean Sea.This led to increased demand for groundwater,which is an essential source for various wate...In the last decade,North Africa has witnessed significant population growth,particularly those bordering the Mediterranean Sea.This led to increased demand for groundwater,which is an essential source for various water uses such as drinking water supplies and irrigation.Generally,human activities play a crucial role in the different quantitative and qualitative changes in groundwater.Now,climate changes such as a decrease in precipitation have also led to a shortage of water resources and a decline in the groundwater table.This paper presents the impact of climate changes on groundwater resources in the Ain Azel region,Setif,northeastern Algeria.The analysis of longterm spatiotemporal variability in rainfall over 63 years(1958–2021)revealed a significant decline in groundwater recharge,especially after 2013.In contrast,the Pettitt and Mann–Kendall tests show increased temperatures with breaks between 1984 and 1986.A piezometric analysis of the alluvial aquifer demonstrated a significant decline in groundwater levels in the last 20 years.Hydrochemical analysis showed that groundwater in the region is dominated by Ca–Mg–Cl water type,which indicates the presence of water salinity phenomenon.Water Quality Index(WQI)analysis showed the deterioration of groundwater in the area,which may be caused by several factors:brine intrusion from the Salt Lake(Sebkha)in the north;the dissolution of evaporites(Triassic)and/or anthropogenic sources of agricultural and industrial origin.Our findings provide an overview summarizing the state of groundwater,which will help improve groundwater resource management in the region in the coming years.展开更多
Two statistical validation methods were used to evaluate the confidence level of the Total Column Ozone (TCO) measurements recorded by satellite systems measuring simultaneously, one using the normal distribution and ...Two statistical validation methods were used to evaluate the confidence level of the Total Column Ozone (TCO) measurements recorded by satellite systems measuring simultaneously, one using the normal distribution and another using the Mann-Whitney test. First, the reliability of the TCO measurements was studied hemispherically. While similar coincidences and levels of significance > 0.05 were found with the two statistical tests, an enormous variability in the levels of significance throughout the year was also exposed. Then, using the same statistical comparison methods, a latitudinal study was carried out in order to elucidate the geographical distribution that gave rise to this variability. Our study reveals that between the TOMS and OMI measurements in 2005 there was only a coincidence in 50% of the latitudes, which explained the variability. This implies that for 2005, the TOMS measurements are not completely reliable, except between the -50° and -15° latitude band in the southern hemisphere and between +15° and +50° latitude band in the northern hemisphere. In the case of OMI-OMPS, we observe that between 2011 and 2016 the measurements of both satellite systems are reasonably similar with a confidence level higher than 95%. However, in 2017 a band with a width of 20° latitude centered on the equator appeared, in which the significance levels were much less than 0.05, indicating that one of the measurement systems had begun to fail. In 2018, the fault was not only located in the equator, but was also replicated in various bands in the Southern Hemisphere. We interpret this as evidence of irreversible failure in one of the measurement systems.展开更多
文摘饮用水水源地水质演变趋势研究对水源地的保护具有重要意义。以中国某城市6个市级水源地为研究对象,采用水质指数法进行水质评价,在此基础上结合Pettitt Mann Whitney变异点分析法、Mann-Kendall趋势检验法和线性回归法,深入分析了各水源地水质突变时间及演变趋势,并结合该市近年来的管理政策分析了水质变化的原因。2020年-2022年各水源地水质现状整体较好,4个水源地水质评价结果为优良,其余为良好。变异点和演变趋势分析结果表明,各水源地均存在突变时间,水质指数突变时间主要集中在2021年2月-2022年4月,突变后2个水源地水质变差,其余水源地水质变好,仅1个水源地变异显著。该市水源地整体上2022年水质状况优于往年,主要得益于流域整体水环境质量改善和水源地特殊保护的加强。
文摘In the last decade,North Africa has witnessed significant population growth,particularly those bordering the Mediterranean Sea.This led to increased demand for groundwater,which is an essential source for various water uses such as drinking water supplies and irrigation.Generally,human activities play a crucial role in the different quantitative and qualitative changes in groundwater.Now,climate changes such as a decrease in precipitation have also led to a shortage of water resources and a decline in the groundwater table.This paper presents the impact of climate changes on groundwater resources in the Ain Azel region,Setif,northeastern Algeria.The analysis of longterm spatiotemporal variability in rainfall over 63 years(1958–2021)revealed a significant decline in groundwater recharge,especially after 2013.In contrast,the Pettitt and Mann–Kendall tests show increased temperatures with breaks between 1984 and 1986.A piezometric analysis of the alluvial aquifer demonstrated a significant decline in groundwater levels in the last 20 years.Hydrochemical analysis showed that groundwater in the region is dominated by Ca–Mg–Cl water type,which indicates the presence of water salinity phenomenon.Water Quality Index(WQI)analysis showed the deterioration of groundwater in the area,which may be caused by several factors:brine intrusion from the Salt Lake(Sebkha)in the north;the dissolution of evaporites(Triassic)and/or anthropogenic sources of agricultural and industrial origin.Our findings provide an overview summarizing the state of groundwater,which will help improve groundwater resource management in the region in the coming years.
文摘Two statistical validation methods were used to evaluate the confidence level of the Total Column Ozone (TCO) measurements recorded by satellite systems measuring simultaneously, one using the normal distribution and another using the Mann-Whitney test. First, the reliability of the TCO measurements was studied hemispherically. While similar coincidences and levels of significance > 0.05 were found with the two statistical tests, an enormous variability in the levels of significance throughout the year was also exposed. Then, using the same statistical comparison methods, a latitudinal study was carried out in order to elucidate the geographical distribution that gave rise to this variability. Our study reveals that between the TOMS and OMI measurements in 2005 there was only a coincidence in 50% of the latitudes, which explained the variability. This implies that for 2005, the TOMS measurements are not completely reliable, except between the -50° and -15° latitude band in the southern hemisphere and between +15° and +50° latitude band in the northern hemisphere. In the case of OMI-OMPS, we observe that between 2011 and 2016 the measurements of both satellite systems are reasonably similar with a confidence level higher than 95%. However, in 2017 a band with a width of 20° latitude centered on the equator appeared, in which the significance levels were much less than 0.05, indicating that one of the measurement systems had begun to fail. In 2018, the fault was not only located in the equator, but was also replicated in various bands in the Southern Hemisphere. We interpret this as evidence of irreversible failure in one of the measurement systems.
