In order to investigate the effect of acid rain on photosynthetic characteristics of spring wheat,spring wheat at the jointing stage was sprayed with simulated acid rain at different pH levels of 1.5,2.5,3.5,4.5 and 5...In order to investigate the effect of acid rain on photosynthetic characteristics of spring wheat,spring wheat at the jointing stage was sprayed with simulated acid rain at different pH levels of 1.5,2.5,3.5,4.5 and 5.6,and then,the photosynthetic parameters of spring wheat leaf was monitored.The results indicated that the pH value of simulated acid rain was positively and very significantly correlated with the net photosynthetic rate,stomata conductance,transpiration rate,water use efficiency and the chlorophyll relative content,whereas very significantly and negatively correlated with intercellular CO2 concentration.Due to acid rain,the net photosynthetic rate,stomata conductance,transpiration rate and the chlorophyll relative content decreased by 4.08%-67.04%,17.44%-58.44%,12.08%-48.08% and 12.16%-37.23% respectively,while intercellular CO2 concentration increased by 9.01%-14.29%.After simulated treatment with acid rain,the net photosynthetic rate had high significant positive correlation with stomata conductance,transpiration rate,water use efficiency,and the chlorophyll relative content,but high significant negative correlation with intercellular CO2 concentration.At the same time,transpiration rate was observed to be very significantly and positively correlated to stomata conductance and chlorophyll relative content,being significantly and positively correlated with water use efficiency,and very significantly and negatively correlated with intercellular CO2 concentration.In a word,the influence of simulated acid rain on photosynthetic characteristics of spring wheat leaf became more and more obvious with the increase of hydrogen ion concentration.展开更多
The spring persistent rains（SPR）over southeastern China（SEC）are a unique synoptic and climatic phenomenon in East Asia.A former study has found that the southwesterly flow which lies on the southeastern flank of t...The spring persistent rains（SPR）over southeastern China（SEC）are a unique synoptic and climatic phenomenon in East Asia.A former study has found that the southwesterly flow which lies on the southeastern flank of the Tibetan Plateau（TP）is one of the deflected westerly flows of the TP,and it is suggested to be the direct climatic cause of SPR.This study found that the southwesterly flow is also highly correlated with the sensible heating of the southeastern TP in interannual variability,in addition to having a high correlation in seasonal variability.These facts suggest that the thermal forcing of the TP is another important climatic cause of SPR.Numerical sensitivity experiments further prove that the mechanical and thermal forcings of the TP are the climatic causes of the formation of the SPR.On the other hand,the Nanling Mountains and Wuyi Mountains（NWM）over southeastern China not only increase the SPR precipitation amount evidently,but also make the SPR rain belt move to the south by blocking the strong southwesterly flow.展开更多
[Objective]The research aimed to study the first spring soaking rain weather and its precipitation enhancement potential forecast in Jinzhou area in 2010.[Method]From the weather situation characteristics,main influen...[Objective]The research aimed to study the first spring soaking rain weather and its precipitation enhancement potential forecast in Jinzhou area in 2010.[Method]From the weather situation characteristics,main influence system,forecast service,artificial precipitation enhancement operation and so on,the first spring soaking rain weather process in Jinzhou area in 2010 was summarized comprehensively.[Result]The weather situation characteristics of soaking rain were that the high-altitude cold air was weak,and the low-level warm wet airflow was obvious.The main influence systems were the high-altitude trough,the high-altitude shear line and the ground Mongolian cyclone.The ground inverted trough system advanced northward and got through with the same phase of Mongolian cyclone,which provided the certain energy and water vapor for the precipitation in Jinzhou area.It was one of key reasons for generating the soaking rain.The numerical forecast product played the certain guidance role in the forecast service work.The situation field forecast was accurate,but the precipitation forecast deviation was big.Therefore,the forecast service couldn’t depend on the numerical forecast product simply and totally,and should combine with the actual monitoring data to analyze and apply comprehensively.[Conclusion]The research played the safeguarding role in carrying out the large-scale artificial precipitation enhancement operation successfully in the whole area of Jinzhou.展开更多
[Objective]The aim was to study the Markov chain prediction method of first heavy rain in spring in Xi’an City.[Method]According to the dependent random variables of the occurrence of heavy rain,precipitation in spri...[Objective]The aim was to study the Markov chain prediction method of first heavy rain in spring in Xi’an City.[Method]According to the dependent random variables of the occurrence of heavy rain,precipitation in spring in seven meteorological stations in Xi’an City from 1959 to 2010 was selected.Its occurrence date was determined by the standard of first heavy rain in spring in meteorology.According to the length of the sequence of the problem and actual situation,six states were divided.And by dint of Markov chain,first heavy rain prediction model in spring was set up.[Result]The predicted occurrence time of first heavy rain in spring in Xi’an in 2009 and 2010 was consistent with the actual situation.The prediction effect was fine.The method had clear thought and was convenient for calculation,with certain dependence and practicality.[Conclusion]This method provided reference value for the actual forecast of first heavy rain in spring.展开更多
This essay directs at the water imagery of two poems Happy Rain on a Spring Night and A Drop Fell on the Apple Tree.Although living in different time and place, Chinese poet Du Fu and American poetess Emily Dickinson ...This essay directs at the water imagery of two poems Happy Rain on a Spring Night and A Drop Fell on the Apple Tree.Although living in different time and place, Chinese poet Du Fu and American poetess Emily Dickinson share some deep understanding of the water. This secret of water imagery is unveiled in this essay with the help of Archetypal Criticism, revealing its significance to the human beings as a race.展开更多
基金Supported by Scientific Research Special Fund for Public Welfare Industry (Meteorology) (GY-HY200806021)Drought Fund Project of Lanzhou Arid Meteorology Institute,China Meteorological Administration (IAM200921)
文摘In order to investigate the effect of acid rain on photosynthetic characteristics of spring wheat,spring wheat at the jointing stage was sprayed with simulated acid rain at different pH levels of 1.5,2.5,3.5,4.5 and 5.6,and then,the photosynthetic parameters of spring wheat leaf was monitored.The results indicated that the pH value of simulated acid rain was positively and very significantly correlated with the net photosynthetic rate,stomata conductance,transpiration rate,water use efficiency and the chlorophyll relative content,whereas very significantly and negatively correlated with intercellular CO2 concentration.Due to acid rain,the net photosynthetic rate,stomata conductance,transpiration rate and the chlorophyll relative content decreased by 4.08%-67.04%,17.44%-58.44%,12.08%-48.08% and 12.16%-37.23% respectively,while intercellular CO2 concentration increased by 9.01%-14.29%.After simulated treatment with acid rain,the net photosynthetic rate had high significant positive correlation with stomata conductance,transpiration rate,water use efficiency,and the chlorophyll relative content,but high significant negative correlation with intercellular CO2 concentration.At the same time,transpiration rate was observed to be very significantly and positively correlated to stomata conductance and chlorophyll relative content,being significantly and positively correlated with water use efficiency,and very significantly and negatively correlated with intercellular CO2 concentration.In a word,the influence of simulated acid rain on photosynthetic characteristics of spring wheat leaf became more and more obvious with the increase of hydrogen ion concentration.
基金support of the Chinese National 973 Program(Grant No.2006CB403600)the National Natural Science Foundation of China(NSFC)Project Nos.40875034,40810059005,40821092,and 40523001
文摘The spring persistent rains（SPR）over southeastern China（SEC）are a unique synoptic and climatic phenomenon in East Asia.A former study has found that the southwesterly flow which lies on the southeastern flank of the Tibetan Plateau（TP）is one of the deflected westerly flows of the TP,and it is suggested to be the direct climatic cause of SPR.This study found that the southwesterly flow is also highly correlated with the sensible heating of the southeastern TP in interannual variability,in addition to having a high correlation in seasonal variability.These facts suggest that the thermal forcing of the TP is another important climatic cause of SPR.Numerical sensitivity experiments further prove that the mechanical and thermal forcings of the TP are the climatic causes of the formation of the SPR.On the other hand,the Nanling Mountains and Wuyi Mountains（NWM）over southeastern China not only increase the SPR precipitation amount evidently,but also make the SPR rain belt move to the south by blocking the strong southwesterly flow.
文摘[Objective]The research aimed to study the first spring soaking rain weather and its precipitation enhancement potential forecast in Jinzhou area in 2010.[Method]From the weather situation characteristics,main influence system,forecast service,artificial precipitation enhancement operation and so on,the first spring soaking rain weather process in Jinzhou area in 2010 was summarized comprehensively.[Result]The weather situation characteristics of soaking rain were that the high-altitude cold air was weak,and the low-level warm wet airflow was obvious.The main influence systems were the high-altitude trough,the high-altitude shear line and the ground Mongolian cyclone.The ground inverted trough system advanced northward and got through with the same phase of Mongolian cyclone,which provided the certain energy and water vapor for the precipitation in Jinzhou area.It was one of key reasons for generating the soaking rain.The numerical forecast product played the certain guidance role in the forecast service work.The situation field forecast was accurate,but the precipitation forecast deviation was big.Therefore,the forecast service couldn’t depend on the numerical forecast product simply and totally,and should combine with the actual monitoring data to analyze and apply comprehensively.[Conclusion]The research played the safeguarding role in carrying out the large-scale artificial precipitation enhancement operation successfully in the whole area of Jinzhou.
文摘[Objective]The aim was to study the Markov chain prediction method of first heavy rain in spring in Xi’an City.[Method]According to the dependent random variables of the occurrence of heavy rain,precipitation in spring in seven meteorological stations in Xi’an City from 1959 to 2010 was selected.Its occurrence date was determined by the standard of first heavy rain in spring in meteorology.According to the length of the sequence of the problem and actual situation,six states were divided.And by dint of Markov chain,first heavy rain prediction model in spring was set up.[Result]The predicted occurrence time of first heavy rain in spring in Xi’an in 2009 and 2010 was consistent with the actual situation.The prediction effect was fine.The method had clear thought and was convenient for calculation,with certain dependence and practicality.[Conclusion]This method provided reference value for the actual forecast of first heavy rain in spring.
文摘This essay directs at the water imagery of two poems Happy Rain on a Spring Night and A Drop Fell on the Apple Tree.Although living in different time and place, Chinese poet Du Fu and American poetess Emily Dickinson share some deep understanding of the water. This secret of water imagery is unveiled in this essay with the help of Archetypal Criticism, revealing its significance to the human beings as a race.
