Urban air pollution is a commonly concerned environmental problem in the world. Identification of air quality trend using long-term monitoring data is helpful to understand the effectiveness of pollution control strat...Urban air pollution is a commonly concerned environmental problem in the world. Identification of air quality trend using long-term monitoring data is helpful to understand the effectiveness of pollution control strategies. This study, using data from six monitoring stations in Zhengzhou City, analyzed the changing trend in concentrations of SO2, NOJNO2 and TSP/PM10 in 1996-2008, based on non-parametric Mann-Kendall test and Sen＇s slope estimator, and evaluated the comprehensive air pollution level using Multi-Pollutant Index （MPI）. It was found that the concen- tration of each pollutant exceeded obviously the World Health Organization （WHO） guideline value, but the changing trend varied： SO2 and NO2 were significantly increased mainly due to an increase in coal consumption and vehicle number, while NOx, TSP and PM10 decreased. The air pollution was serious, and differed markedly among the three functional regions： it is the most severe in the Industrial and Residential Area （IRA）, followed by the Transportation Hub and Business District （THBD）, and then the High-tech, Cultural and Educational Area （HCEA）. Different from NO2 concentration that had a similar change trend/rate among the function regions, the change rate of PM10 concentra- tion differed spatially, decreased much more obviously in THBD than other two regions. For the whole city, the com- prehensive air pollution level declined gradually, illustrating that the air quality in Zhengzhou was improved in the last decade.展开更多
Water pollution is one of the major environmental prob- lems, especially in urban areas. Due to rapid urban expansion and industrialization, water pollution in Zhengzhou City, the capital of Henan Province in central ...Water pollution is one of the major environmental prob- lems, especially in urban areas. Due to rapid urban expansion and industrialization, water pollution in Zhengzhou City, the capital of Henan Province in central China has become a serious problem for its development. In this study, the surface water quality was evalu- ated using Nemerow Comprehensive Pollution Index （NCPI）, and the change trend was calculated using methods of Mann-Kendall test and Sen＇s slope estimator, based on the monitoring data from 1998 to 2008. The results show that the NCP1 ranged from 3 to 50 in 70% of the monitoring cases, implying that most rivers were seriously polluted. However, this serious polltuon is expected to be gradually improved, as the concentration of water pollutants and NCPI declined significantly in most rivers. Water pollution in reservoirs was much lower than rivers, and the NCPI in the three monitored reservoirs was lower than 3 in most years, and shows a downward trend. Although the surface water quality was gradually improved, great efforts are still needed to enhance the protection and improvement of surface water environment.展开更多
Bangladesh is one in all the foremost climate vulnerable countries of the world. In recent years, climate change studies over the country get plenty of attention by the researchers and policy makers. A substantial qua...Bangladesh is one in all the foremost climate vulnerable countries of the world. In recent years, climate change studies over the country get plenty of attention by the researchers and policy makers. A substantial quantity of global climate change studies over the country use climate models to estimate future projections and uncertainties. Maximum temperature, precipitation and their potential future changes are evaluated in an ensemble of the 5th Phase Coupled Model Inter-comparison Project (CMIP5) within the Intergovernmental Panel on Climate Change (IPCC) diagnostic exercise for the Fifth Assessment Report (AR5) and the available historical data collected by the Bangladesh Meteorological Department (BMD) during the period 1981-2008 in the north-western region of Bangladesh and also the comparison between these two values. It has been found that average maximum temperature shows a positive trend of increase at a rate of 0.29°C and 5.3°C per century respectively, for BMD data and MPI-ESM-LR (CMIP5) model data. But the rainfall is decreasing at a rate of 8.8 mm and 40.1 mm per century respectively for BMD data and MPI-ESM-LR (CMIP5) model data. It is seen that July was the maximum monsoon rainfall month and January was the lowest rainfall month. The peak frequency is slightly smaller than 12 months, which indicates that the major events are occurring before ending a year compared to the previous year. According to MPI-ESM-LR (CMIP5) model data, future normal temperature on north-western region will be increased at a rate of 1.62°C during the period 2040-2100.展开更多
The main purpose of this study is to highlight, on the basis of statistical tests, the significant long-term changes of the Mediterranean Sea level, through the analysis of historical tide gauge records. In this frame...The main purpose of this study is to highlight, on the basis of statistical tests, the significant long-term changes of the Mediterranean Sea level, through the analysis of historical tide gauge records. In this framework, 14 tide gauge monthly series selected from the Permanent Service of the Mean Sea Level(PSMSL) database were used. The search for the presence or not of trends within these series, that have a temporal coverage from 59 to 142 years, was carried out using the Mann-Kendall test and the Sen’s slope estimator. The obtained results show that the Split Rt Marjana series are the only ones which does not exhibit a significant trend. The other 13 series show significant increasing trends. This result seems sufficient to suppose the presence, in the past century, of a new climatic phase on the scale of the Mediterranean basin, where the rising sea level is one of the consequences.展开更多
For sustainable water resource management,it is important to determine the relationship between streamfl ow and other variables that infl uence availability of water resources.However,many catchments do not have suffi...For sustainable water resource management,it is important to determine the relationship between streamfl ow and other variables that infl uence availability of water resources.However,many catchments do not have suffi cient data to allow for a more detailed study of these relationships.We faced a similar challenge in the Chengcun Basin(limited historical data: from 1986–1999); and therefore we used a new approach to overcome this.We found that,using nonparametric trend methods in conjunction with the climate elasticity analyses and the 2D visualization of hydrologic data,it is possible to assess the relationships between streamfl ow and other hydro-climatic variables.In the past,streamfl ow trends in the basin were more correlated with precipitation than with potential evapotranspiration(PET).In addition,there is a gradual shift in the hydrological regime of the catchment,which may affect the occurrence of available water resources and activities that depend on them.In addition,based on our climate sensitivity analyses,the streamfl ow is dependent and more sensitive to variations in precipitation than to PET(δQ=0.79δP+0.42δE; precipitation elasticity,ε P=1.32; PET elasticity,ε E=-2.10).Therefore pending more detailed studies,the use of our approach will provide a rapid means to assess the variation of water resources(streamfl ow)in a watershed.In the future,we hope to carry out related research in other watersheds and also perform a more detailed studies to improve upon the results of this study.展开更多
Based on global solar radiation and related meteorological data from 57 stations in China between 1961 and 2009, we analyze the variation of surface global solar radiation (G) and its relationship to meteorological el...Based on global solar radiation and related meteorological data from 57 stations in China between 1961 and 2009, we analyze the variation of surface global solar radiation (G) and its relationship to meteorological elements using linear-trend estimation, wavelet analysis, and the Mann-Kendall test. The results show that of the 33 stations with time series longer than 45 years, G is significant at the 95% confidence level. G has a decreasing trend at many stations, but results vary across different areas. The decadal departure percentage of G increased from the 1960s to 1970s, declined gradually after the 1970s, and decreased significantly in the 1980s. In the 1990s, the trend at a few sites slightly increased. The trend of cumulative variance is of four types, i.e. rise-fall, rise-fall-slight rise, rise-fall-rise, and not obvious. For changes within a year, the most obvious decline was in winter, and the rest of the year had a slight decrease. The major cycles of annual G were 6-9, 10-13, and 29-33 a. The inflection points were mostly in the 1970s. The reasons for greater changes were complex. Relevant meteorological elements were selected and analyzed by statistical methods. Trends in climatic parameters, such as annual average percentage of sunshine, annual average wind speed, and annual average of low cloud cover, were closely related to G. Thus, this indicated the potential causes of the observed trends in G. The long-term trend for annual G in some regions was also influenced by anthro- pogenic activities. Annual average percentage of sunshine and annual average wind speed were positively correlated with annual G, respectively.展开更多
基金Under the auspices of National Natural Science Foundation of China (No. 41071063)
文摘Urban air pollution is a commonly concerned environmental problem in the world. Identification of air quality trend using long-term monitoring data is helpful to understand the effectiveness of pollution control strategies. This study, using data from six monitoring stations in Zhengzhou City, analyzed the changing trend in concentrations of SO2, NOJNO2 and TSP/PM10 in 1996-2008, based on non-parametric Mann-Kendall test and Sen＇s slope estimator, and evaluated the comprehensive air pollution level using Multi-Pollutant Index （MPI）. It was found that the concen- tration of each pollutant exceeded obviously the World Health Organization （WHO） guideline value, but the changing trend varied： SO2 and NO2 were significantly increased mainly due to an increase in coal consumption and vehicle number, while NOx, TSP and PM10 decreased. The air pollution was serious, and differed markedly among the three functional regions： it is the most severe in the Industrial and Residential Area （IRA）, followed by the Transportation Hub and Business District （THBD）, and then the High-tech, Cultural and Educational Area （HCEA）. Different from NO2 concentration that had a similar change trend/rate among the function regions, the change rate of PM10 concentra- tion differed spatially, decreased much more obviously in THBD than other two regions. For the whole city, the com- prehensive air pollution level declined gradually, illustrating that the air quality in Zhengzhou was improved in the last decade.
文摘Water pollution is one of the major environmental prob- lems, especially in urban areas. Due to rapid urban expansion and industrialization, water pollution in Zhengzhou City, the capital of Henan Province in central China has become a serious problem for its development. In this study, the surface water quality was evalu- ated using Nemerow Comprehensive Pollution Index （NCPI）, and the change trend was calculated using methods of Mann-Kendall test and Sen＇s slope estimator, based on the monitoring data from 1998 to 2008. The results show that the NCP1 ranged from 3 to 50 in 70% of the monitoring cases, implying that most rivers were seriously polluted. However, this serious polltuon is expected to be gradually improved, as the concentration of water pollutants and NCPI declined significantly in most rivers. Water pollution in reservoirs was much lower than rivers, and the NCPI in the three monitored reservoirs was lower than 3 in most years, and shows a downward trend. Although the surface water quality was gradually improved, great efforts are still needed to enhance the protection and improvement of surface water environment.
文摘Bangladesh is one in all the foremost climate vulnerable countries of the world. In recent years, climate change studies over the country get plenty of attention by the researchers and policy makers. A substantial quantity of global climate change studies over the country use climate models to estimate future projections and uncertainties. Maximum temperature, precipitation and their potential future changes are evaluated in an ensemble of the 5th Phase Coupled Model Inter-comparison Project (CMIP5) within the Intergovernmental Panel on Climate Change (IPCC) diagnostic exercise for the Fifth Assessment Report (AR5) and the available historical data collected by the Bangladesh Meteorological Department (BMD) during the period 1981-2008 in the north-western region of Bangladesh and also the comparison between these two values. It has been found that average maximum temperature shows a positive trend of increase at a rate of 0.29°C and 5.3°C per century respectively, for BMD data and MPI-ESM-LR (CMIP5) model data. But the rainfall is decreasing at a rate of 8.8 mm and 40.1 mm per century respectively for BMD data and MPI-ESM-LR (CMIP5) model data. It is seen that July was the maximum monsoon rainfall month and January was the lowest rainfall month. The peak frequency is slightly smaller than 12 months, which indicates that the major events are occurring before ending a year compared to the previous year. According to MPI-ESM-LR (CMIP5) model data, future normal temperature on north-western region will be increased at a rate of 1.62°C during the period 2040-2100.
文摘The main purpose of this study is to highlight, on the basis of statistical tests, the significant long-term changes of the Mediterranean Sea level, through the analysis of historical tide gauge records. In this framework, 14 tide gauge monthly series selected from the Permanent Service of the Mean Sea Level(PSMSL) database were used. The search for the presence or not of trends within these series, that have a temporal coverage from 59 to 142 years, was carried out using the Mann-Kendall test and the Sen’s slope estimator. The obtained results show that the Split Rt Marjana series are the only ones which does not exhibit a significant trend. The other 13 series show significant increasing trends. This result seems sufficient to suppose the presence, in the past century, of a new climatic phase on the scale of the Mediterranean basin, where the rising sea level is one of the consequences.
基金Supported by the Hohai University Scholarship Schemethe National Natural Science Foundation of China(Nos.41130639,51179045,41101017,412010208)the Innovation Program for Graduates in Jiangsu Province,China(No.CXZZ13_02)
文摘For sustainable water resource management,it is important to determine the relationship between streamfl ow and other variables that infl uence availability of water resources.However,many catchments do not have suffi cient data to allow for a more detailed study of these relationships.We faced a similar challenge in the Chengcun Basin(limited historical data: from 1986–1999); and therefore we used a new approach to overcome this.We found that,using nonparametric trend methods in conjunction with the climate elasticity analyses and the 2D visualization of hydrologic data,it is possible to assess the relationships between streamfl ow and other hydro-climatic variables.In the past,streamfl ow trends in the basin were more correlated with precipitation than with potential evapotranspiration(PET).In addition,there is a gradual shift in the hydrological regime of the catchment,which may affect the occurrence of available water resources and activities that depend on them.In addition,based on our climate sensitivity analyses,the streamfl ow is dependent and more sensitive to variations in precipitation than to PET(δQ=0.79δP+0.42δE; precipitation elasticity,ε P=1.32; PET elasticity,ε E=-2.10).Therefore pending more detailed studies,the use of our approach will provide a rapid means to assess the variation of water resources(streamfl ow)in a watershed.In the future,we hope to carry out related research in other watersheds and also perform a more detailed studies to improve upon the results of this study.
基金supported by the Special Scientific Research Fund of the Meteorological Public Welfare Profession of China (Grant No.GYHY201006036)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No.IAP09303)the Major State Basic Research Development Program of China (Grant No.2010CB428401)
文摘Based on global solar radiation and related meteorological data from 57 stations in China between 1961 and 2009, we analyze the variation of surface global solar radiation (G) and its relationship to meteorological elements using linear-trend estimation, wavelet analysis, and the Mann-Kendall test. The results show that of the 33 stations with time series longer than 45 years, G is significant at the 95% confidence level. G has a decreasing trend at many stations, but results vary across different areas. The decadal departure percentage of G increased from the 1960s to 1970s, declined gradually after the 1970s, and decreased significantly in the 1980s. In the 1990s, the trend at a few sites slightly increased. The trend of cumulative variance is of four types, i.e. rise-fall, rise-fall-slight rise, rise-fall-rise, and not obvious. For changes within a year, the most obvious decline was in winter, and the rest of the year had a slight decrease. The major cycles of annual G were 6-9, 10-13, and 29-33 a. The inflection points were mostly in the 1970s. The reasons for greater changes were complex. Relevant meteorological elements were selected and analyzed by statistical methods. Trends in climatic parameters, such as annual average percentage of sunshine, annual average wind speed, and annual average of low cloud cover, were closely related to G. Thus, this indicated the potential causes of the observed trends in G. The long-term trend for annual G in some regions was also influenced by anthro- pogenic activities. Annual average percentage of sunshine and annual average wind speed were positively correlated with annual G, respectively.
