Spatiotemporal variation of seed rain reflects the response of plants in terms of their reproductive strategy to environmental gradients.In this study,we collected seeds from four sites in the Dalaoling Nature Reserve...Spatiotemporal variation of seed rain reflects the response of plants in terms of their reproductive strategy to environmental gradients.In this study,we collected seeds from four sites in the Dalaoling Nature Reserve,Hubei Province,China,between 2011 and 2014,measured seed output and seed mass as seed rain traits,and compared their interannual and elevational variation.Then,we ran phylogenetic generalized mixed linear models(PGLMMs) to explore the effects of temperature and precipitation as well as interspecific differences on seed rain,and fitted the best regression models for seed rain vs.weather of canopy and understory species.The results showed no correlation between values of seed output and seed mass.However,the variation of the two traits showed significantly positive correlation.Seed output of canopy species generally decreased with increasing elevation,and showed significant interannual difference;however,seed output of understory species and seed mass for both canopy and understory species did not show consistency tends along elevational or in interannual variation.Seed output was significantly affected by temperature and precipitation,while seed mass mainly varied due to interspecific differences.Weather explained more the variation of the seed output of canopy species than that of understory species,with R^(2) values of 43.0%and 29.9%,respectively.These results suggested that canopy plants contributed more to the reproductive dynamics of the whole communities,and the canopy's buffer effect on the underground weakened the response of understory plants to weather variation in terms of their reproductive strategy.展开更多
In this study, a new rain type classification algorithm for the Dual-Frequency Precipitation Radar(DPR) suitable over the Tibetan Plateau(TP) was proposed by analyzing Global Precipitation Measurement(GPM) DPR Level-2...In this study, a new rain type classification algorithm for the Dual-Frequency Precipitation Radar(DPR) suitable over the Tibetan Plateau(TP) was proposed by analyzing Global Precipitation Measurement(GPM) DPR Level-2 data in summer from 2014 to 2020. It was found that the DPR rain type classification algorithm(simply called DPR algorithm) has mis-identification problems in two aspects in summer TP. In the new algorithm of rain type classification in summer TP,four rain types are classified by using new thresholds, such as the maximum reflectivity factor, the difference between the maximum reflectivity factor and the background maximum reflectivity factor, and the echo top height. In the threshold of the maximum reflectivity factors, 30 d BZ and 18 d BZ are both thresholds to separate strong convective precipitation, weak convective precipitation and weak precipitation. The results illustrate obvious differences of radar reflectivity factor and vertical velocity among the three rain types in summer TP, such as the reflectivity factor of most strong convective precipitation distributes from 15 d BZ to near 35 d BZ from 4 km to 13 km, and increases almost linearly with the decrease in height. For most weak convective precipitation, the reflectivity factor distributes from 15 d BZ to 28 d BZ with the height from 4 km to 9 km. For weak precipitation, the reflectivity factor mainly distributes in range of 15–25 d BZ with height within 4–10 km. It is also shows that weak precipitation is the dominant rain type in summer TP, accounting for 40%–80%,followed by weak convective precipitation(25%–40%), and strong convective precipitation has the least proportion(less than 30%).展开更多
Vegetation restoration and reconstruction are effective approaches to desertification control and achieving social and economic sustainability in desert areas.However,the self-succession ability of native plants durin...Vegetation restoration and reconstruction are effective approaches to desertification control and achieving social and economic sustainability in desert areas.However,the self-succession ability of native plants during the later periods of vegetation restoration remains unclear.Therefore,this study was conducted to bridge the knowledge gap by investigating the regeneration dynamics of artificial forest under natural conditions.The information of seed rain and soil seed bank was collected and quantified from an artificial Caragana korshinskii Kom.forest in the Tengger Desert,China.The germination tests were conducted in a laboratory setting.The analysis of species quantity and diversity in seed rain and soil seed bank was conducted to assess the impact of different durations of sand fixation(60,40,and 20 a)on the progress of vegetation restoration and ecological conditions in artificial C.korshinskii forest.The results showed that the top three dominant plant species in seed rain were Echinops gmelinii Turcz.,Eragrostis minor Host.,and Agropyron mongolicum Keng.,and the top three dominant plant species in soil seed bank were E.minor,Chloris virgata Sw.,and E.gmelinii.As restoration period increased,the density of seed rain and soil seed bank increased first and then decreased.While for species richness,as restoration period increased,it gradually increased in seed rain but decreased in soil seed bank.There was a positive correlation between seed rain density and soil seed bank density among all the three restoration periods.The species similarity between seed rain or soil seed bank and aboveground vegetation decreased with the extension of restoration period.The shape of the seeds,specifically those with external appendages such as spines and crown hair,clearly had an effect on their dispersal,then resulting in lower seed density in soil seed bank.In addition,precipitation was a crucial factor in promoting rapid germination,also resulting in lower seed density in soil seed bank.Our findings provide valuable insights for guiding future interventions during the later periods of artificial C.korshinskii forest,such as sowing and restoration efforts using unmanned aerial vehicles.展开更多
An extreme torrential rain(ETR)event occurred in Henan Province,China,during 18-21 July 2021.Based on hourly rain-gauge observations and ERA5 reanalysis data,the ETR was studied from the perspective of kinetic energy(...An extreme torrential rain(ETR)event occurred in Henan Province,China,during 18-21 July 2021.Based on hourly rain-gauge observations and ERA5 reanalysis data,the ETR was studied from the perspective of kinetic energy(K),which can be divided into rotational wind(V_(R))kinetic energy(K_(R)),divergent wind kinetic energy(K_(D)),and the kinetic energy of the interaction between the divergent and rotational winds(K_(RD)).According to the hourly precipitation intensity variability,the ETR process was divided into an initial stage,a rapid increase stage,and maintenance stage.Results showed that the intensification and maintenance of ETR were closely related to the upper-level K,and most closely related to the upperlevel K_(R),with a correlation coefficient of up to 0.9.In particular,the peak value of hourly rainfall intensity lagged behind the K_(R) by 8 h.Furthermore,diagnosis showed that K transformation from unresolvable to resolvable scales made the ETR increase slowly.The meridional rotational wind(u_(R))and meridional gradient of the geopotential(φ)jointly determined the conversion of available potential energy(APE)to K_(R) through the barotropic process,which dominated the rapid enhancement of K_(R) and then caused the rapid increase in ETR.The transportation of K by rotational wind consumed K_(R),and basically offset the K_(R) produced by the barotropic process,which basically kept K_(R) stable at a high value,thus maintaining the ETR.展开更多
Objective: To explore the application effect of CBL combined with rain classroom teaching method in medical statistics courses. Methods: The undergraduate students of medical imaging technology in 2019 and 2020 in a u...Objective: To explore the application effect of CBL combined with rain classroom teaching method in medical statistics courses. Methods: The undergraduate students of medical imaging technology in 2019 and 2020 in a university were selected as the research objects. A cluster sampling method was used to select 79 undergraduate students from 2019 in the control group and 75 undergraduate students from 2020 in the experimental group. Traditional teaching method and CBL combined with rain classroom teaching method was used in the control group and experimental group respectively. The final examination scores of the two groups were compared. In experimental group, the correlation between the average score in the rain classroom and the final examination score was tested, and the teaching effect was evaluated. Results: The average score of final examination in experimental group and control group was 79.13 ± 10.32 points and 71.54 ± 14.752 points, respectively, which had a statistically significant difference (Z = 2.586, P = 0.012);the final examination scores of the students in the experimental group were positively correlated with the average scores of the rain classroom (r = 0.372, P = 0.001), and the proportion of satisfaction in the experimental group was 94.7%. Conclusion: The CBL combined with rain classroom teaching method can improve the teaching effectiveness of medical statistics courses.展开更多
A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics...A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.展开更多
Adaptation measures were proposed using“Sunny Rain”to solve Tel Aviv’s environmental problems to cool the air in the city and save humanity from climate catastrophe and fight air pollution;the Yarkon,“Tel Aviv’s ...Adaptation measures were proposed using“Sunny Rain”to solve Tel Aviv’s environmental problems to cool the air in the city and save humanity from climate catastrophe and fight air pollution;the Yarkon,“Tel Aviv’s main river”will no longer be a dirty ditch;the fog from Ben-Gurion Airport was cleaned;neighborhoods,parks,around Tel Aviv were greened and all green spaces were irrigated with“Sunny Rain”.展开更多
The East African short rainy season (October-November-December) is one of the major flood seasons in the East African region. The amount of rainfall during the short rainy season is closely related to the lives of the...The East African short rainy season (October-November-December) is one of the major flood seasons in the East African region. The amount of rainfall during the short rainy season is closely related to the lives of the people and the socio-economic development of the area. By using precipitation data and sea surface temperature data, this study reveals the spatial and temporal variation patterns of extreme precipitation during the East African short rainy season. Key findings include significant rainfall variability, with Tanzania experiencing the highest amounts in December due to the southward shift of the Intertropical Convergence Zone (ITCZ), while other regions receive less than 100 mm. Extreme rainfall events (90th percentiles) are evenly distributed, averaging 2 to 10 days annually. Historical data shows maximum seasonal rainfall often peaks at 15 mm, with frequent occurrences of daily rainfall exceeding 10 mm during OND. Additionally, a positive correlation (0.48) between OND precipitation extremes and Indian Ocean Dipole (IOD) anomalies is statistically significant. These findings highlight the climatic variability and potential trends in extreme rainfall events in East Africa, providing valuable insights for regional climate adaptation strategies.展开更多
The temporal-spatial distribution and seasonal variation of the precipitation acidity in Guangxi Province were statistically analyzed by means of the data from 2003 to 2008 in 10 Stations of Acid Rain Observation in t...The temporal-spatial distribution and seasonal variation of the precipitation acidity in Guangxi Province were statistically analyzed by means of the data from 2003 to 2008 in 10 Stations of Acid Rain Observation in the province and the data from 1996 to 2008 in two Monitoring Spots in Nanning and Baise,respectively.The results showed that annual average pH value of precipitation was <5.6 based on the analysis of the data from 10 Stations of Acid Rain Observation in the province,among which,the data from 5 stations indicated that annual average pH value of precipitation was <4.5.Thus,it can be thought that the serious acid rain had appeared in the province.There was an obvious seasonal variation in the extent of the acidity in precipitation and the acidity of precipitation in spring and winter was heavier than that in summer and autumn.展开更多
Environmental problem is one of three major issues of common concern in the world today.Being a developing socialist country,the environmental problems in china are even more prominent,mainly in population expansion,s...Environmental problem is one of three major issues of common concern in the world today.Being a developing socialist country,the environmental problems in china are even more prominent,mainly in population expansion,sharp decrease of global forest areas,soil erosion,acid rain pollution,water pollution and so on.This essay is to introduce the present status,formation causes and hazardous condition of acid rain pollution in china.Some feasible and effective control measures are put forward according to the actual situation in China.展开更多
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 variation characteristics of acid rain and the relationship between the formation of acid rain and meteorological conditions were analyzed based on the observation data and meteorological records collected from ac...The variation characteristics of acid rain and the relationship between the formation of acid rain and meteorological conditions were analyzed based on the observation data and meteorological records collected from acid rain observation station in Dalian over 2006-2009.The results showed that Dalian was one of the regions with strong acid rain in northern China,with the frequency of 66% and pH value of 3.49.The acidity was the strongest in fall and weakest in spring;and the maximum and minimum frequencies were in summer and in winter respectively.Frequency of acid rain was inversely proportional to wind speed and concentration of inhalable particles in Dalian;acid rain occurred easily in foggy weather due to the steady stratification and abundant moisture;continuous precipitation did not mean the reduction of acidic material in the air,and the rainfall with increased acidity in the second day accounted for 42% in continuous precipitation cases.展开更多
Dual-frequency and multi-polarization spaceborne rain and cloud measuring radar is the inevitable trend of remote sensing techniques.Techniques of new generation dual-frequency and multi-polarization spaceborne rain a...Dual-frequency and multi-polarization spaceborne rain and cloud measuring radar is the inevitable trend of remote sensing techniques.Techniques of new generation dual-frequency and multi-polarization spaceborne rain and cloud measuring radar are studied systematically.Radar block diagram and main parameters are presented.Antenna subsystem scheme is analyzed and antenna parameters are proposed.Central electronic device subsystem scheme is given and data rate of spaceborne radar is calculated.This paper is a meaningful try for carrying out spaceborne rain and cloud measuring radar design,acting as a reference to Chinese spaceborne rain and cloud measuring radar design and production in future.展开更多
A model based on the non-linear artificial neural network (ANN) is established to predict the thickness of the water film on road surfaces. The weight and the threshold can be determined by training test data, and t...A model based on the non-linear artificial neural network (ANN) is established to predict the thickness of the water film on road surfaces. The weight and the threshold can be determined by training test data, and the water film thickness on the road surface can be accurately predicted by the empirical verification based on sample data. Results show that the proposed ANN model is feasible to predict the water film thickness of the road surface.展开更多
Based on the rainfall monitoring data and high altitude meteorological data,the present situation of acid rain pollution in Nanchang City was analyzed and the forming factors of acid rain were revealed. The results sh...Based on the rainfall monitoring data and high altitude meteorological data,the present situation of acid rain pollution in Nanchang City was analyzed and the forming factors of acid rain were revealed. The results showed that acid rain in Nanchang had the characteristics of high acidity and frequency,and the pH value of rainfall reduced in recent years,belonging to sulfuric acid type,and the most serious acid rain pollution appeared in autumn and winter. The pH value of rainfall went up with the improvement of rainfall grade,and the increase of rainfall quantity had diluting effect on the rainfall acidity. High altitude meteorological conditions affected acid rain obviously,when the upper wind velocity was below 7 m/s,the frequency of acid rain was higher and its pH value was lower,with serious acid rain pollution,and it showed that upper wind had diluting effect on the horizontal transport of pollutants. The frequency of acid rain became higher with stronger inversion intensity. Moreover,the surrounding industrial areas had obvious effect on the formation of acid rain. Unstable meteorological conditions were beneficial to the horizontal and vertical diffusion of pollution in the lower atmosphere,reducing the effect of induced-acidity pollutants on a region.展开更多
Ernest Hemingway is always regarded as masculinity by the critics.His early stories won wide critical praise for their stoic,understanding"masculine"study and their graphic depiction of male pursuits and att...Ernest Hemingway is always regarded as masculinity by the critics.His early stories won wide critical praise for their stoic,understanding"masculine"study and their graphic depiction of male pursuits and attitudes.However,in addition to his male depiction in his novels,Hemingway,in fact,is also a writer who cares and shows sympathy and concern towards women.Then Cat in the Rain is one of his typical work which focuses on the aspirations of women.With analysis on the characters,plot and description of settings etc.in the story,Hemingway’s real attitude toward female is explicated.展开更多
Based on MICAPS(Meteorological Information Combine Analysis and Process System) and observational data in Anshan Observatory,the freezing rain event occurred rarely in Anshan on February 24 in 2010 was analyzed.The re...Based on MICAPS(Meteorological Information Combine Analysis and Process System) and observational data in Anshan Observatory,the freezing rain event occurred rarely in Anshan on February 24 in 2010 was analyzed.The results showed that there existed the inversion layer from the ground to 850 hpa level even to 700 hPa level when the local surface temperature was below 0 ℃.The temperature stratification structure of coldness-warmth-coldness was prevailing from the upper level to the ground with the existence of the ice melting layer of a certain thickness.Thus the freezing event occurred in Anshan.展开更多
Labov的语篇分析模式为叙事语篇的分析提供了具有指导意义的操作方法。他所提出的分析模式包括点题、指向、进展、评议、结局和回应六个部分。结合这一模式分析Cat in the Rain一文的叙事结构,探讨该语篇的特点,以期进一步了解作者谋篇...Labov的语篇分析模式为叙事语篇的分析提供了具有指导意义的操作方法。他所提出的分析模式包括点题、指向、进展、评议、结局和回应六个部分。结合这一模式分析Cat in the Rain一文的叙事结构,探讨该语篇的特点,以期进一步了解作者谋篇布局的超结构和写作意图。展开更多
基金the Second Tibetan Plateau Scientific Expedition and Research Program (STEP)(No.2019QZKK0402)。
文摘Spatiotemporal variation of seed rain reflects the response of plants in terms of their reproductive strategy to environmental gradients.In this study,we collected seeds from four sites in the Dalaoling Nature Reserve,Hubei Province,China,between 2011 and 2014,measured seed output and seed mass as seed rain traits,and compared their interannual and elevational variation.Then,we ran phylogenetic generalized mixed linear models(PGLMMs) to explore the effects of temperature and precipitation as well as interspecific differences on seed rain,and fitted the best regression models for seed rain vs.weather of canopy and understory species.The results showed no correlation between values of seed output and seed mass.However,the variation of the two traits showed significantly positive correlation.Seed output of canopy species generally decreased with increasing elevation,and showed significant interannual difference;however,seed output of understory species and seed mass for both canopy and understory species did not show consistency tends along elevational or in interannual variation.Seed output was significantly affected by temperature and precipitation,while seed mass mainly varied due to interspecific differences.Weather explained more the variation of the seed output of canopy species than that of understory species,with R^(2) values of 43.0%and 29.9%,respectively.These results suggested that canopy plants contributed more to the reproductive dynamics of the whole communities,and the canopy's buffer effect on the underground weakened the response of understory plants to weather variation in terms of their reproductive strategy.
基金funded by the National Natural Science Foundation of China project (Grant Nos.42275140, 42230612, 91837310, 92037000)the Second Tibetan Plateau Scientific Expedition and Research (STEP) program(Grant No. 2019QZKK0104)。
文摘In this study, a new rain type classification algorithm for the Dual-Frequency Precipitation Radar(DPR) suitable over the Tibetan Plateau(TP) was proposed by analyzing Global Precipitation Measurement(GPM) DPR Level-2 data in summer from 2014 to 2020. It was found that the DPR rain type classification algorithm(simply called DPR algorithm) has mis-identification problems in two aspects in summer TP. In the new algorithm of rain type classification in summer TP,four rain types are classified by using new thresholds, such as the maximum reflectivity factor, the difference between the maximum reflectivity factor and the background maximum reflectivity factor, and the echo top height. In the threshold of the maximum reflectivity factors, 30 d BZ and 18 d BZ are both thresholds to separate strong convective precipitation, weak convective precipitation and weak precipitation. The results illustrate obvious differences of radar reflectivity factor and vertical velocity among the three rain types in summer TP, such as the reflectivity factor of most strong convective precipitation distributes from 15 d BZ to near 35 d BZ from 4 km to 13 km, and increases almost linearly with the decrease in height. For most weak convective precipitation, the reflectivity factor distributes from 15 d BZ to 28 d BZ with the height from 4 km to 9 km. For weak precipitation, the reflectivity factor mainly distributes in range of 15–25 d BZ with height within 4–10 km. It is also shows that weak precipitation is the dominant rain type in summer TP, accounting for 40%–80%,followed by weak convective precipitation(25%–40%), and strong convective precipitation has the least proportion(less than 30%).
基金funded by the General Project of Key R&D Plan of Ningxia Hui Autonomous Region,China(2021BEG03008,2022BEG02012)the Science and Technology Innovation Leading Talent Project of Ningxia Hui Autonomous Region(2021GKLRLX13)the National Natural Science Foundation of China(31760707).
文摘Vegetation restoration and reconstruction are effective approaches to desertification control and achieving social and economic sustainability in desert areas.However,the self-succession ability of native plants during the later periods of vegetation restoration remains unclear.Therefore,this study was conducted to bridge the knowledge gap by investigating the regeneration dynamics of artificial forest under natural conditions.The information of seed rain and soil seed bank was collected and quantified from an artificial Caragana korshinskii Kom.forest in the Tengger Desert,China.The germination tests were conducted in a laboratory setting.The analysis of species quantity and diversity in seed rain and soil seed bank was conducted to assess the impact of different durations of sand fixation(60,40,and 20 a)on the progress of vegetation restoration and ecological conditions in artificial C.korshinskii forest.The results showed that the top three dominant plant species in seed rain were Echinops gmelinii Turcz.,Eragrostis minor Host.,and Agropyron mongolicum Keng.,and the top three dominant plant species in soil seed bank were E.minor,Chloris virgata Sw.,and E.gmelinii.As restoration period increased,the density of seed rain and soil seed bank increased first and then decreased.While for species richness,as restoration period increased,it gradually increased in seed rain but decreased in soil seed bank.There was a positive correlation between seed rain density and soil seed bank density among all the three restoration periods.The species similarity between seed rain or soil seed bank and aboveground vegetation decreased with the extension of restoration period.The shape of the seeds,specifically those with external appendages such as spines and crown hair,clearly had an effect on their dispersal,then resulting in lower seed density in soil seed bank.In addition,precipitation was a crucial factor in promoting rapid germination,also resulting in lower seed density in soil seed bank.Our findings provide valuable insights for guiding future interventions during the later periods of artificial C.korshinskii forest,such as sowing and restoration efforts using unmanned aerial vehicles.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.42275013,42030611 and 42175008)the Open Grants of the State Key Laboratory of Severe Weather(Grant No.2021LASWB17)。
文摘An extreme torrential rain(ETR)event occurred in Henan Province,China,during 18-21 July 2021.Based on hourly rain-gauge observations and ERA5 reanalysis data,the ETR was studied from the perspective of kinetic energy(K),which can be divided into rotational wind(V_(R))kinetic energy(K_(R)),divergent wind kinetic energy(K_(D)),and the kinetic energy of the interaction between the divergent and rotational winds(K_(RD)).According to the hourly precipitation intensity variability,the ETR process was divided into an initial stage,a rapid increase stage,and maintenance stage.Results showed that the intensification and maintenance of ETR were closely related to the upper-level K,and most closely related to the upperlevel K_(R),with a correlation coefficient of up to 0.9.In particular,the peak value of hourly rainfall intensity lagged behind the K_(R) by 8 h.Furthermore,diagnosis showed that K transformation from unresolvable to resolvable scales made the ETR increase slowly.The meridional rotational wind(u_(R))and meridional gradient of the geopotential(φ)jointly determined the conversion of available potential energy(APE)to K_(R) through the barotropic process,which dominated the rapid enhancement of K_(R) and then caused the rapid increase in ETR.The transportation of K by rotational wind consumed K_(R),and basically offset the K_(R) produced by the barotropic process,which basically kept K_(R) stable at a high value,thus maintaining the ETR.
文摘Objective: To explore the application effect of CBL combined with rain classroom teaching method in medical statistics courses. Methods: The undergraduate students of medical imaging technology in 2019 and 2020 in a university were selected as the research objects. A cluster sampling method was used to select 79 undergraduate students from 2019 in the control group and 75 undergraduate students from 2020 in the experimental group. Traditional teaching method and CBL combined with rain classroom teaching method was used in the control group and experimental group respectively. The final examination scores of the two groups were compared. In experimental group, the correlation between the average score in the rain classroom and the final examination score was tested, and the teaching effect was evaluated. Results: The average score of final examination in experimental group and control group was 79.13 ± 10.32 points and 71.54 ± 14.752 points, respectively, which had a statistically significant difference (Z = 2.586, P = 0.012);the final examination scores of the students in the experimental group were positively correlated with the average scores of the rain classroom (r = 0.372, P = 0.001), and the proportion of satisfaction in the experimental group was 94.7%. Conclusion: The CBL combined with rain classroom teaching method can improve the teaching effectiveness of medical statistics courses.
基金National Natural Science Foundation of China(41930972,52239006,41975001)。
文摘A second rain belt sometimes occurs ahead of a frontal rain belt in the warm sector over coastal South China,leading to heavy precipitation.We examined the differences in the mesoscale characteristics and microphysics of the frontal and warm sector rain belts that occurred in South China on May 10–13,2022.The southern rain belt occurred in an environment with favorable mesoscale conditions but weak large-scale forcing.In contrast,the northern rain belt was related to low-level horizontal shear and the surface-level front.The interaction between the enhanced southeasterly winds and the rainfall-induced cold pool promoted the persistent growth of convection along the southern rain belt.The convective cell propagated east over the coastal area,where there was a large temperature gradient.The bow-shaped echo in this region may be closely related to the rear-inflow jet.By contrast,the initial convection of the northern rain belt was triggered along the front and the region of low-level horizontal shear,with mesoscale interactions between the enhanced warm-moist southeasterly airflow and the cold dome associated with the earlier rain.The terrain blocked the movement of the cold pool,resulting in the stagnation of the frontal convective cell at an early stage.Subsequently,a meso-γ-scale vortex formed during the rapid movement of the convective cell,corresponding to an enhancement of precipitation.The representative raindrop spectra for the southern rain belt were characterized by a greater number and higher density of raindrops than the northern rain belt,even though both resulted in comparable hourly rainfalls.These results help us better understand the characteristics of double rain belts over South China.
文摘Adaptation measures were proposed using“Sunny Rain”to solve Tel Aviv’s environmental problems to cool the air in the city and save humanity from climate catastrophe and fight air pollution;the Yarkon,“Tel Aviv’s main river”will no longer be a dirty ditch;the fog from Ben-Gurion Airport was cleaned;neighborhoods,parks,around Tel Aviv were greened and all green spaces were irrigated with“Sunny Rain”.
文摘The East African short rainy season (October-November-December) is one of the major flood seasons in the East African region. The amount of rainfall during the short rainy season is closely related to the lives of the people and the socio-economic development of the area. By using precipitation data and sea surface temperature data, this study reveals the spatial and temporal variation patterns of extreme precipitation during the East African short rainy season. Key findings include significant rainfall variability, with Tanzania experiencing the highest amounts in December due to the southward shift of the Intertropical Convergence Zone (ITCZ), while other regions receive less than 100 mm. Extreme rainfall events (90th percentiles) are evenly distributed, averaging 2 to 10 days annually. Historical data shows maximum seasonal rainfall often peaks at 15 mm, with frequent occurrences of daily rainfall exceeding 10 mm during OND. Additionally, a positive correlation (0.48) between OND precipitation extremes and Indian Ocean Dipole (IOD) anomalies is statistically significant. These findings highlight the climatic variability and potential trends in extreme rainfall events in East Africa, providing valuable insights for regional climate adaptation strategies.
文摘The temporal-spatial distribution and seasonal variation of the precipitation acidity in Guangxi Province were statistically analyzed by means of the data from 2003 to 2008 in 10 Stations of Acid Rain Observation in the province and the data from 1996 to 2008 in two Monitoring Spots in Nanning and Baise,respectively.The results showed that annual average pH value of precipitation was <5.6 based on the analysis of the data from 10 Stations of Acid Rain Observation in the province,among which,the data from 5 stations indicated that annual average pH value of precipitation was <4.5.Thus,it can be thought that the serious acid rain had appeared in the province.There was an obvious seasonal variation in the extent of the acidity in precipitation and the acidity of precipitation in spring and winter was heavier than that in summer and autumn.
文摘Environmental problem is one of three major issues of common concern in the world today.Being a developing socialist country,the environmental problems in china are even more prominent,mainly in population expansion,sharp decrease of global forest areas,soil erosion,acid rain pollution,water pollution and so on.This essay is to introduce the present status,formation causes and hazardous condition of acid rain pollution in china.Some feasible and effective control measures are put forward according to the actual situation in China.
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Supported by Scientific Research Special Fund for Public Welfare Industry (Meteorology) (GYHY20080620)
文摘The variation characteristics of acid rain and the relationship between the formation of acid rain and meteorological conditions were analyzed based on the observation data and meteorological records collected from acid rain observation station in Dalian over 2006-2009.The results showed that Dalian was one of the regions with strong acid rain in northern China,with the frequency of 66% and pH value of 3.49.The acidity was the strongest in fall and weakest in spring;and the maximum and minimum frequencies were in summer and in winter respectively.Frequency of acid rain was inversely proportional to wind speed and concentration of inhalable particles in Dalian;acid rain occurred easily in foggy weather due to the steady stratification and abundant moisture;continuous precipitation did not mean the reduction of acidic material in the air,and the rainfall with increased acidity in the second day accounted for 42% in continuous precipitation cases.
基金Supported by Horizontal Program of Space Long March Rocket Technology Co. Ltd (500036)
文摘Dual-frequency and multi-polarization spaceborne rain and cloud measuring radar is the inevitable trend of remote sensing techniques.Techniques of new generation dual-frequency and multi-polarization spaceborne rain and cloud measuring radar are studied systematically.Radar block diagram and main parameters are presented.Antenna subsystem scheme is analyzed and antenna parameters are proposed.Central electronic device subsystem scheme is given and data rate of spaceborne radar is calculated.This paper is a meaningful try for carrying out spaceborne rain and cloud measuring radar design,acting as a reference to Chinese spaceborne rain and cloud measuring radar design and production in future.
文摘A model based on the non-linear artificial neural network (ANN) is established to predict the thickness of the water film on road surfaces. The weight and the threshold can be determined by training test data, and the water film thickness on the road surface can be accurately predicted by the empirical verification based on sample data. Results show that the proposed ANN model is feasible to predict the water film thickness of the road surface.
基金Supported by Major Project of Chinese National Program for Fundamental Research and Development("973" Program)(2005CB42- 208)Meteorological Science and Technology Innovation Foundation of Jiangxi Province,China(2006KJC-X1006)
文摘Based on the rainfall monitoring data and high altitude meteorological data,the present situation of acid rain pollution in Nanchang City was analyzed and the forming factors of acid rain were revealed. The results showed that acid rain in Nanchang had the characteristics of high acidity and frequency,and the pH value of rainfall reduced in recent years,belonging to sulfuric acid type,and the most serious acid rain pollution appeared in autumn and winter. The pH value of rainfall went up with the improvement of rainfall grade,and the increase of rainfall quantity had diluting effect on the rainfall acidity. High altitude meteorological conditions affected acid rain obviously,when the upper wind velocity was below 7 m/s,the frequency of acid rain was higher and its pH value was lower,with serious acid rain pollution,and it showed that upper wind had diluting effect on the horizontal transport of pollutants. The frequency of acid rain became higher with stronger inversion intensity. Moreover,the surrounding industrial areas had obvious effect on the formation of acid rain. Unstable meteorological conditions were beneficial to the horizontal and vertical diffusion of pollution in the lower atmosphere,reducing the effect of induced-acidity pollutants on a region.
文摘Ernest Hemingway is always regarded as masculinity by the critics.His early stories won wide critical praise for their stoic,understanding"masculine"study and their graphic depiction of male pursuits and attitudes.However,in addition to his male depiction in his novels,Hemingway,in fact,is also a writer who cares and shows sympathy and concern towards women.Then Cat in the Rain is one of his typical work which focuses on the aspirations of women.With analysis on the characters,plot and description of settings etc.in the story,Hemingway’s real attitude toward female is explicated.
文摘Based on MICAPS(Meteorological Information Combine Analysis and Process System) and observational data in Anshan Observatory,the freezing rain event occurred rarely in Anshan on February 24 in 2010 was analyzed.The results showed that there existed the inversion layer from the ground to 850 hpa level even to 700 hPa level when the local surface temperature was below 0 ℃.The temperature stratification structure of coldness-warmth-coldness was prevailing from the upper level to the ground with the existence of the ice melting layer of a certain thickness.Thus the freezing event occurred in Anshan.