[Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi （Tubificidae） on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and ...[Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi （Tubificidae） on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and mechanism of benthic Annelida in coupling process of benthic-pelagic interface.[Method]Using chemically stable glass beads as tracers,the vertical transport of sedimentary particles in paddy field was analyzed comparatively with and without B.sowerbyi.[Result]After 10 days＇ bioturbation of B.sowerbyi,41.3% of the glass beads on the surface of sedimentary particles were transferred downward to the maximum depth of 9.4 cm,and the vertical transportation rate of sedimentary particles was 1.370×10-3/（g·cm2·d）. 25.8% and 17.3% of glass beads at a depth of 6 cm were transferred upwards and downwards respectively after bioturbation,to the maximum depth of 5.2 and 2.7 cm respectively,and the vertical transportation rates of sedimentary particles were 8.557×10-4 and 5.738×10-4/（g·cm2·d） respectively.[Conclusion]The sedimentary particles on the surface and deep layer of the paddy field were vertically shifted by the physical activities of B.sowerbyi,thus changed the sedimentary environment.展开更多
Deep water in the South China Sea is renewed by the cold and dense Luzon Strait overflow.However,from where and how the deep water upwells is poorly understood yet.Based on the Hybrid Coordinate Ocean Model reanalysis...Deep water in the South China Sea is renewed by the cold and dense Luzon Strait overflow.However,from where and how the deep water upwells is poorly understood yet.Based on the Hybrid Coordinate Ocean Model reanalysis data,vertical velocity is derived to answer these questions.Domain-integrated vertical velocity is of two maxima,one in the shallow water and the other at depth,and separated by a layer of minimum at the bottom of the thermocline.Further analysis shows that this two-segmented vertical transport is attributed to the vertical compensation of subsurface water to the excessive outflow of shallow water and upward push of the dense Luzon Strait overflow,respectively.In the abyssal basin,the vertical transport increases upward from zero at the depth of 3500–4000 m and reaches a maximum of 1.5×10^(6) m^(3)/s at about 1500 m.Deep water upwells mainly from the northeastern and southwestern ends of the abyssal basin and off the continental slopes.To explain the upward velocity arising from slope breaks,a possible mechanism is proposed that an onshore velocity component can be derived from the deep western boundary current above steep slopes under bottom friction.展开更多
A convective cloud transport model, without chemical processes, is developed by joining a set of concentration conservative equations into a two-dimensional, slab-symmetric and fully elastic numerical cloud model, and...A convective cloud transport model, without chemical processes, is developed by joining a set of concentration conservative equations into a two-dimensional, slab-symmetric and fully elastic numerical cloud model, and a numerical experiment is completed to simulate the vertical transport of ground-borne, inert gaseous pollutant by deepthunderstorm. The simulation shows that deep convective storm can very effectively transport high concentrated pollutant gas from PBL upward to the upper troposphere in 30 to 40 minutes, where the pollutant spreads laterally outward with strong anvil outflow, forming an extensive high concentration area. Meanwhile, relatively low concentration areas are formed in PBL both below and beside the cloud, mainly caused by dynamic pumping effect and sub-cloud downdraft flow. About 80% of the pollutant gas transported to the upper troposphere is from the layer below 1.5 km AGL (above ground level).展开更多
Gravity-1 was the world's first carrier rocket to adopt the sea-based “three vertical” testing launch mode. This article introduces the overall layout of the launch site and the workflow of rocket testing and la...Gravity-1 was the world's first carrier rocket to adopt the sea-based “three vertical” testing launch mode. This article introduces the overall layout of the launch site and the workflow of rocket testing and launch for its maiden flight mission. The process of vertical assembly, vertical testing, vertical transportation, and sea-based hot launches are explained. Additionally, it provides an outlook on the improved “three vertical” testing and launch mode for future missions, such as land-based launches, rapid launches, and remote sea launches.展开更多
A simulation experiment on vertical transport of herbicide atrazine (2 chloro 4 ethylamino 6 isopropylamino s triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leachi...A simulation experiment on vertical transport of herbicide atrazine (2 chloro 4 ethylamino 6 isopropylamino s triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leaching water and soil samples in column at 8 layers with 10 cm thick of each layer were detected by high performance liquid chromatography. The results show total atrazine amount in leaching water increases nonlinearly with the leaching time and the herbicide application rate, and the atrazine concentrations in column soil decrease with the vertical depth after water leaching. The distribution of atrazine mass in the system after 154 days were that among the applied atrazine, 0.3% is out through leaching water, 1% is methanol extractable residues in soil, 46% is methanol nonextractable residues in soil, and 52% is other loss (including volatilization and degradation). The study indicates movement of atrazine in agriculture soil may not only have relation to the properties of herbicide, but also to the herbicide application history.展开更多
Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for...Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial applications.In the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle velocity.The hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow velocities.During transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture velocity.The qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were investigated.The local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic gradient.The effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.展开更多
Proper application of nitrogen（N） fertilizers and irrigation management are important production practices that can reduce nitrate leaching into groundwater and improve the N use efficiency（NUE）. A lysimeter/rain ...Proper application of nitrogen（N） fertilizers and irrigation management are important production practices that can reduce nitrate leaching into groundwater and improve the N use efficiency（NUE）. A lysimeter/rain shelter facility was used to study effects of the rate of N fertilization, type of N fertilizer, and irrigation level on key aspects of winter wheat production over three growing seasons（response variables were nitrate transport, N leaching, and NUE）. Results indicated that nitrate concentration in the soil profile and N leaching increased with the rate of N fertilization. At the end of the third season, nitrate concentration in the top 0–75 cm layer of soil was higher with manure treatment while urea treatments resulted in higher concentrations in the 100–200 cm layer. With normal irrigation, 3.4 to 15.3% of N from applied fertilizer was leached from the soil, yet no leaching occurred under a stress irrigation treatment. The manure treatment experienced less N leaching than the urea treatment in all cases except for the 180 kg N ha^-1 rate in 2011–2012（season 3）. In terms of grain yield（GY）, dry matter（DM） or NUE parameters, values for the manure treatment were lower than for the urea treatment in 2009–2010（season 1）, yet were otherwise higher for urea treatment in season 3. GY and crop nitrogen uptake（NU） were elevated when the rate of N fertilizer increased, while the NUE decreased; GY, DM, and NU increased with the amount of irrigation. Data indicated that reduced rates of N fertilization combined with increased manure application and proper irrigation management can lower nitrate levels in the subsoil and reduce potential N leaching into groundwater.展开更多
Rare earth elements （REEs） increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus （P） from heavily fertilized soils. The vertical transport character...Rare earth elements （REEs） increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus （P） from heavily fertilized soils. The vertical transport characteristics of P and REEs, lanthanum （La）, neodymium （Nd）, samarium （Sin）, and cerium （Ce）, were investigated with addition of exogenous REEs at various doses to packed soil columns （20 cm deep）. Vertical transfers of REEs and P were relatively small, with transport depths less than 6 cm for most REEs and P. Export of applied REEs in leachate accounted for less that 5% of inputs. The addition of Ce, Nd and Sm to soil columns significantly decreased concentrations of extractable soil P up to a depth of 4 cm, with soil P concentrations unaffected at depths 〉 4 cm. In general, REEs had little effect on the vertical leaching of P in packed soil columns.展开更多
A discussion of the mass transport of the Hadley circulation is presented, with regard to its longitudinal structure. Data from the NCEP/NCAR reanalysis data set for the period 1948-2005 is examined, focusing on the s...A discussion of the mass transport of the Hadley circulation is presented, with regard to its longitudinal structure. Data from the NCEP/NCAR reanalysis data set for the period 1948-2005 is examined, focusing on the solsticial seasons of June-August and December-February. Quantitative estimates have been extracted from the data to observe connections between the zonal mean of the upper tropospheric north/south mass transports and their relationship to the driving factor of tropical precipitation （implying latent heat release） and subsidence in the subtropical high pressure belts. The longitudinal structure of this flow is then examined with regard to these three main variables. The poleward upper tropospheric transport has four （JJA） or three （DJF） main branches, which link regions of major precipitation with corresponding regions of large subsidence, and one （June, July, August） or two （December, January, February） reverse branches. This structure has remained stable over the past sixty years. Although the total upper tropospheric transport in each season is less than the total sinking transport in the target subtropical high pressure belt, this does not apply to the individual branches, the balance being made up by the upper tropospheric reverse transports. An analysis of correlations between all of these various components shows, however, that the complete picture is more complex, with some precipitation regions being linked to subsidence regions outside their own branch.展开更多
Vertical cumulus momentum transport is an important physical process in the tropical atmosphere and plays a key role in the evolution of the tropical atmospheric system. This paper focuses on the impact of the vertica...Vertical cumulus momentum transport is an important physical process in the tropical atmosphere and plays a key role in the evolution of the tropical atmospheric system. This paper focuses on the impact of the vertical cumulus momentum transport on Madden-Julian Oscillation （MJO） simulation in two global climate models （GCMs）. The Tiedtke cumulus parameterization scheme is applied to both GCMs [CAM2 and Spectral Atmospheric general circulation Model of LASG/IAP （SAMIL）]. It is found that the MJO simulation ability might be influenced by the vertical cumulus momentum transport through the cumulus parameterization scheme. However, the use of vertical momentum transport in different models provides different results. In order to improve model＇s MJO simulation ability, we must introduce vertical cumulus momentum transport in a more reasonable way into models. Furthermore, the coherence of the parameterization and the underlying model also need to be considered.展开更多
Measurements of surface O3 and carbon monoxide（CO） were made from September 2009 to August 2011 at Dangxiong（30.48°N, 91.10°E, 4187 m a.s.l.）, a remote highland site in a southern valley of the Nyainq...Measurements of surface O3 and carbon monoxide（CO） were made from September 2009 to August 2011 at Dangxiong（30.48°N, 91.10°E, 4187 m a.s.l.）, a remote highland site in a southern valley of the Nyainqêntanglha Mountains in the Tibetan Plateau, China. The monthly mean O3 mixing ratio ranged from 29.1 to 51.4 ppb, with an average of 38.5 ppb, and the maximum value was observed in May. The average diurnal cycle of O3 concentration showed a minimum in early morning and a maximum in the afternoon, with a broader ＂high platform＂ from the late morning to the late afternoon, and resembled that of surface wind speed. The concentration of surface O3 was highly significantly correlated with tropospheric column O3 over the regions surrounding Dangxiong and with that of surface O3 observed at a site north of the Nyainqêntanglha Mountains, suggesting a good regional representativeness of surface O3 at Dangxiong. In the afternoon when stronger winds blew, surface air showed distinct features of free-atmospheric air, with higher O3, lower CO, and lower relative humidity（RH）. The negative O3-CO and O3-RH correlations in most months indicate a significant influence of air masses from the free troposphere. Trajectory analysis suggests that air masses originating from the south of the site make a negative net contribution to surface O3 and a positive contribution to CO and humidity, and those from the northwest sector contribute conversely to the respective quantities.展开更多
By aggregating MODIS（moderate-resolution imaging spectroradiometer） AOD（aerosol optical depth） and OMI（ozone monitoring instrument） UVAI（ultra violet aerosol index）datasets over 2010–2014, it was found that p...By aggregating MODIS（moderate-resolution imaging spectroradiometer） AOD（aerosol optical depth） and OMI（ozone monitoring instrument） UVAI（ultra violet aerosol index）datasets over 2010–2014, it was found that peak aerosol loading in seasonal variation occurred annually in spring over the Gulf of Tonkin（17–23°N, 105–110°E）. The vertical structure of the aerosol extinction coefficient retrieved from the spaceborne lidar CALIOP（cloud-aerosol lidar with orthogonal polarization） showed that the springtime peak AOD could be attributed to an abrupt increase in aerosol loading between altitudes of 2 and 5 km.In contrast, aerosol loading in the low atmosphere（below 1 km） was only half of that in winter. Wind fields in the low and high atmosphere exhibited opposite transportation patterns in spring over the Gulf of Tonkin, implying different sources for each level. By comparing the emission inventory of anthropogenic sources with biomass burning, and analyzing the seasonal variation of the vertical structure of aerosols over the Northern Indo-China Peninsula（NIC）, it was concluded that biomass burning emissions contributed to high aerosol loading in spring. The relatively high topography and the high surface temperature in spring made planetary boundary layer height greater than 3 km over NIC. In addition, small-scale cumulus convection frequently occurred, facilitating pollutant rising to over 3 km, which was a height favoring long-range transport. Thus, pollutants emitted from biomass burning over NIC in spring were raised to the high atmosphere, then experienced long-range transport, leading to the increase in aerosol loading at high altitudes over the Gulf of Tonkin during spring.展开更多
Generally speaking,the systems of deep-sea mining consist of a mining support vessel at surface,a seafloor collector on seabed,and a vertical transport system connecting them.The traditional vertical transport systems...Generally speaking,the systems of deep-sea mining consist of a mining support vessel at surface,a seafloor collector on seabed,and a vertical transport system connecting them.The traditional vertical transport systems of deep-sea mining,which are either hydraulic or airlift,have low efficiency and high cost.In this paper,a kind of buoyancy vertical transport system of deep-sea mining is briefly described.Unlike the traditional ones,this new transport system is based on buoyancy and gravity,which could work in arbitrary depth of water but cheaper.展开更多
Stratospheric water vapor variations,which may play an important role in surface climate,have drawn extensive studies.Here,the variation in stratospheric water vapor is investigated by using data from observations of ...Stratospheric water vapor variations,which may play an important role in surface climate,have drawn extensive studies.Here,the variation in stratospheric water vapor is investigated by using data from observations of the Microwave Limb Sounder(MLS)on the Aura satellite,from the ECMWF Interim Reanalysis(ERAI),and simulations by the Whole Atmosphere Community Climate Model(WACCM).We find that the differences of annual mean stratospheric water vapor among these datasets may be partly caused by the differences in vertical transports.Using budget analysis,we find that the upward transport of water vapor at 100 h Pa is mainly located over the Pacific warm pool region and South America in the equatorial tropics in boreal winter and over the southeast of the South Asian high and south of North America in boreal summer.It is found that temperature averaged over regions with upward transport is a better indicator of interannual variability of tropical mean stratospheric water vapor than the tropical mean temperature.It seems that the distributions of the seasonal cycle amplitude of lower stratospheric water vapor in the tropics can also be impacted by the vertical transport.The radiative effects of the interannual changes in water vapor in the lowermost stratosphere are underestimated by approximately 29%in both ERAI and WACCM compared to MLS,although the interannual variations of water vapor in the lowermost stratosphere are dramatically overestimated in ERAI and WACCM.The results here indicate that the radiative effect of long-term changes in water vapor in the lowermost stratosphere may be underestimated in both ERAI and WACCM simulations.展开更多
基金Supported by National Natural Science Foundation of China(31070421 )Human Resources and Social Security Department Students Abroad Science and Technology Activities Preferred Foundation (Human and Social Council Issued 2008-86)+8 种基金Talent Development Fund Project in Jilin Province (Jilin 2007-259)Jilin Province Science and Technology Development Project (20060577 )Technology Project Jilin Provincial Ministry of Education (20094352006113 20071692010150)The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (2005-546)Changchun Normal University Natural Science Foundation(2009002)Northeast Normal University Natural Science Foundation for Young Scholar(20050406)~~
文摘[Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi （Tubificidae） on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and mechanism of benthic Annelida in coupling process of benthic-pelagic interface.[Method]Using chemically stable glass beads as tracers,the vertical transport of sedimentary particles in paddy field was analyzed comparatively with and without B.sowerbyi.[Result]After 10 days＇ bioturbation of B.sowerbyi,41.3% of the glass beads on the surface of sedimentary particles were transferred downward to the maximum depth of 9.4 cm,and the vertical transportation rate of sedimentary particles was 1.370×10-3/（g·cm2·d）. 25.8% and 17.3% of glass beads at a depth of 6 cm were transferred upwards and downwards respectively after bioturbation,to the maximum depth of 5.2 and 2.7 cm respectively,and the vertical transportation rates of sedimentary particles were 8.557×10-4 and 5.738×10-4/（g·cm2·d） respectively.[Conclusion]The sedimentary particles on the surface and deep layer of the paddy field were vertically shifted by the physical activities of B.sowerbyi,thus changed the sedimentary environment.
基金The National Key Research and Development Program of China under contract No.2019YFC1408400the National Natural Science Foundation of China under contract Nos 41876029,41821004 and 41776042.
文摘Deep water in the South China Sea is renewed by the cold and dense Luzon Strait overflow.However,from where and how the deep water upwells is poorly understood yet.Based on the Hybrid Coordinate Ocean Model reanalysis data,vertical velocity is derived to answer these questions.Domain-integrated vertical velocity is of two maxima,one in the shallow water and the other at depth,and separated by a layer of minimum at the bottom of the thermocline.Further analysis shows that this two-segmented vertical transport is attributed to the vertical compensation of subsurface water to the excessive outflow of shallow water and upward push of the dense Luzon Strait overflow,respectively.In the abyssal basin,the vertical transport increases upward from zero at the depth of 3500–4000 m and reaches a maximum of 1.5×10^(6) m^(3)/s at about 1500 m.Deep water upwells mainly from the northeastern and southwestern ends of the abyssal basin and off the continental slopes.To explain the upward velocity arising from slope breaks,a possible mechanism is proposed that an onshore velocity component can be derived from the deep western boundary current above steep slopes under bottom friction.
基金This Project is supported by the National Natural Science Foundation of China.
文摘A convective cloud transport model, without chemical processes, is developed by joining a set of concentration conservative equations into a two-dimensional, slab-symmetric and fully elastic numerical cloud model, and a numerical experiment is completed to simulate the vertical transport of ground-borne, inert gaseous pollutant by deepthunderstorm. The simulation shows that deep convective storm can very effectively transport high concentrated pollutant gas from PBL upward to the upper troposphere in 30 to 40 minutes, where the pollutant spreads laterally outward with strong anvil outflow, forming an extensive high concentration area. Meanwhile, relatively low concentration areas are formed in PBL both below and beside the cloud, mainly caused by dynamic pumping effect and sub-cloud downdraft flow. About 80% of the pollutant gas transported to the upper troposphere is from the layer below 1.5 km AGL (above ground level).
文摘Gravity-1 was the world's first carrier rocket to adopt the sea-based “three vertical” testing launch mode. This article introduces the overall layout of the launch site and the workflow of rocket testing and launch for its maiden flight mission. The process of vertical assembly, vertical testing, vertical transportation, and sea-based hot launches are explained. Additionally, it provides an outlook on the improved “three vertical” testing and launch mode for future missions, such as land-based launches, rapid launches, and remote sea launches.
基金Foundationitem :theNationalNaturalSciencesFoundationofChina (No .2 97770 2 6)andtheMajorProjectFoundationoftheChineseAcademyof
文摘A simulation experiment on vertical transport of herbicide atrazine (2 chloro 4 ethylamino 6 isopropylamino s triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leaching water and soil samples in column at 8 layers with 10 cm thick of each layer were detected by high performance liquid chromatography. The results show total atrazine amount in leaching water increases nonlinearly with the leaching time and the herbicide application rate, and the atrazine concentrations in column soil decrease with the vertical depth after water leaching. The distribution of atrazine mass in the system after 154 days were that among the applied atrazine, 0.3% is out through leaching water, 1% is methanol extractable residues in soil, 46% is methanol nonextractable residues in soil, and 52% is other loss (including volatilization and degradation). The study indicates movement of atrazine in agriculture soil may not only have relation to the properties of herbicide, but also to the herbicide application history.
基金financially supported by the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(Grant No.520LH052)the National Natural Science Foundation of China(Grant No.51909164).
文摘Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial applications.In the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle velocity.The hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow velocities.During transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture velocity.The qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were investigated.The local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic gradient.The effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.
基金supported by the National Natural Science Foundation of China(31171497)the European Union’s Seventh Framework Programme(NUE-CROPS 222645)+3 种基金the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2013BAD07B06-2)the Modern Agro-Industry Technology Research System(CARS-02)the Shandong Province Agricultural (Maize) Breeding Project, China(lnlzz2013-1)the Special Fund for Agro-Scientific Research in the Public Interest,China(201203096, 201203100)
文摘Proper application of nitrogen（N） fertilizers and irrigation management are important production practices that can reduce nitrate leaching into groundwater and improve the N use efficiency（NUE）. A lysimeter/rain shelter facility was used to study effects of the rate of N fertilization, type of N fertilizer, and irrigation level on key aspects of winter wheat production over three growing seasons（response variables were nitrate transport, N leaching, and NUE）. Results indicated that nitrate concentration in the soil profile and N leaching increased with the rate of N fertilization. At the end of the third season, nitrate concentration in the top 0–75 cm layer of soil was higher with manure treatment while urea treatments resulted in higher concentrations in the 100–200 cm layer. With normal irrigation, 3.4 to 15.3% of N from applied fertilizer was leached from the soil, yet no leaching occurred under a stress irrigation treatment. The manure treatment experienced less N leaching than the urea treatment in all cases except for the 180 kg N ha^-1 rate in 2011–2012（season 3）. In terms of grain yield（GY）, dry matter（DM） or NUE parameters, values for the manure treatment were lower than for the urea treatment in 2009–2010（season 1）, yet were otherwise higher for urea treatment in season 3. GY and crop nitrogen uptake（NU） were elevated when the rate of N fertilizer increased, while the NUE decreased; GY, DM, and NU increased with the amount of irrigation. Data indicated that reduced rates of N fertilization combined with increased manure application and proper irrigation management can lower nitrate levels in the subsoil and reduce potential N leaching into groundwater.
基金Supported by the National Natural Science Foundation of China(Nos.40871225 and 40571146)the Short-Term Visiting Program for Advanced Scholars,Chinese Academy of Sciences
文摘Rare earth elements （REEs） increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus （P） from heavily fertilized soils. The vertical transport characteristics of P and REEs, lanthanum （La）, neodymium （Nd）, samarium （Sin）, and cerium （Ce）, were investigated with addition of exogenous REEs at various doses to packed soil columns （20 cm deep）. Vertical transfers of REEs and P were relatively small, with transport depths less than 6 cm for most REEs and P. Export of applied REEs in leachate accounted for less that 5% of inputs. The addition of Ce, Nd and Sm to soil columns significantly decreased concentrations of extractable soil P up to a depth of 4 cm, with soil P concentrations unaffected at depths 〉 4 cm. In general, REEs had little effect on the vertical leaching of P in packed soil columns.
文摘A discussion of the mass transport of the Hadley circulation is presented, with regard to its longitudinal structure. Data from the NCEP/NCAR reanalysis data set for the period 1948-2005 is examined, focusing on the solsticial seasons of June-August and December-February. Quantitative estimates have been extracted from the data to observe connections between the zonal mean of the upper tropospheric north/south mass transports and their relationship to the driving factor of tropical precipitation （implying latent heat release） and subsidence in the subtropical high pressure belts. The longitudinal structure of this flow is then examined with regard to these three main variables. The poleward upper tropospheric transport has four （JJA） or three （DJF） main branches, which link regions of major precipitation with corresponding regions of large subsidence, and one （June, July, August） or two （December, January, February） reverse branches. This structure has remained stable over the past sixty years. Although the total upper tropospheric transport in each season is less than the total sinking transport in the target subtropical high pressure belt, this does not apply to the individual branches, the balance being made up by the upper tropospheric reverse transports. An analysis of correlations between all of these various components shows, however, that the complete picture is more complex, with some precipitation regions being linked to subsidence regions outside their own branch.
基金supported by the National Natural Science Foundation of China under (Grant No. 40575027)
文摘Vertical cumulus momentum transport is an important physical process in the tropical atmosphere and plays a key role in the evolution of the tropical atmospheric system. This paper focuses on the impact of the vertical cumulus momentum transport on Madden-Julian Oscillation （MJO） simulation in two global climate models （GCMs）. The Tiedtke cumulus parameterization scheme is applied to both GCMs [CAM2 and Spectral Atmospheric general circulation Model of LASG/IAP （SAMIL）]. It is found that the MJO simulation ability might be influenced by the vertical cumulus momentum transport through the cumulus parameterization scheme. However, the use of vertical momentum transport in different models provides different results. In order to improve model＇s MJO simulation ability, we must introduce vertical cumulus momentum transport in a more reasonable way into models. Furthermore, the coherence of the parameterization and the underlying model also need to be considered.
基金supported by the Natural Science Foundation of China (Nos. 21177157, 40830102)the Basic Research Fund of CAMS (No. 2011Z003)China Special Fund for Meteorological Research in the Public Interest (No. GYHY201106023)
文摘Measurements of surface O3 and carbon monoxide（CO） were made from September 2009 to August 2011 at Dangxiong（30.48°N, 91.10°E, 4187 m a.s.l.）, a remote highland site in a southern valley of the Nyainqêntanglha Mountains in the Tibetan Plateau, China. The monthly mean O3 mixing ratio ranged from 29.1 to 51.4 ppb, with an average of 38.5 ppb, and the maximum value was observed in May. The average diurnal cycle of O3 concentration showed a minimum in early morning and a maximum in the afternoon, with a broader ＂high platform＂ from the late morning to the late afternoon, and resembled that of surface wind speed. The concentration of surface O3 was highly significantly correlated with tropospheric column O3 over the regions surrounding Dangxiong and with that of surface O3 observed at a site north of the Nyainqêntanglha Mountains, suggesting a good regional representativeness of surface O3 at Dangxiong. In the afternoon when stronger winds blew, surface air showed distinct features of free-atmospheric air, with higher O3, lower CO, and lower relative humidity（RH）. The negative O3-CO and O3-RH correlations in most months indicate a significant influence of air masses from the free troposphere. Trajectory analysis suggests that air masses originating from the south of the site make a negative net contribution to surface O3 and a positive contribution to CO and humidity, and those from the northwest sector contribute conversely to the respective quantities.
基金supported by the National Science Foundation (No.41575127)the Special Welfare Foundation for Environment Protection (No.201309016)the National Basic Research Foundation for Commonwealth Research Institute (No.GYK5051201)
文摘By aggregating MODIS（moderate-resolution imaging spectroradiometer） AOD（aerosol optical depth） and OMI（ozone monitoring instrument） UVAI（ultra violet aerosol index）datasets over 2010–2014, it was found that peak aerosol loading in seasonal variation occurred annually in spring over the Gulf of Tonkin（17–23°N, 105–110°E）. The vertical structure of the aerosol extinction coefficient retrieved from the spaceborne lidar CALIOP（cloud-aerosol lidar with orthogonal polarization） showed that the springtime peak AOD could be attributed to an abrupt increase in aerosol loading between altitudes of 2 and 5 km.In contrast, aerosol loading in the low atmosphere（below 1 km） was only half of that in winter. Wind fields in the low and high atmosphere exhibited opposite transportation patterns in spring over the Gulf of Tonkin, implying different sources for each level. By comparing the emission inventory of anthropogenic sources with biomass burning, and analyzing the seasonal variation of the vertical structure of aerosols over the Northern Indo-China Peninsula（NIC）, it was concluded that biomass burning emissions contributed to high aerosol loading in spring. The relatively high topography and the high surface temperature in spring made planetary boundary layer height greater than 3 km over NIC. In addition, small-scale cumulus convection frequently occurred, facilitating pollutant rising to over 3 km, which was a height favoring long-range transport. Thus, pollutants emitted from biomass burning over NIC in spring were raised to the high atmosphere, then experienced long-range transport, leading to the increase in aerosol loading at high altitudes over the Gulf of Tonkin during spring.
文摘Generally speaking,the systems of deep-sea mining consist of a mining support vessel at surface,a seafloor collector on seabed,and a vertical transport system connecting them.The traditional vertical transport systems of deep-sea mining,which are either hydraulic or airlift,have low efficiency and high cost.In this paper,a kind of buoyancy vertical transport system of deep-sea mining is briefly described.Unlike the traditional ones,this new transport system is based on buoyancy and gravity,which could work in arbitrary depth of water but cheaper.
基金Supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0604)Key Laboratory of Middle Atmosphere and Global Environment Observation(LAGEO-2020-09)+3 种基金Fundamental Research Funds for the Central Universitiessupported by the National Natural Science Foundation of China(41530423,41761144072,and 41888101)grants from the Discovery Program of the Natural Sciences and Engineering Research Council of Canada(RGPIN-2019-04511)from the Canadian Space Agency(16SUASURDC)。
文摘Stratospheric water vapor variations,which may play an important role in surface climate,have drawn extensive studies.Here,the variation in stratospheric water vapor is investigated by using data from observations of the Microwave Limb Sounder(MLS)on the Aura satellite,from the ECMWF Interim Reanalysis(ERAI),and simulations by the Whole Atmosphere Community Climate Model(WACCM).We find that the differences of annual mean stratospheric water vapor among these datasets may be partly caused by the differences in vertical transports.Using budget analysis,we find that the upward transport of water vapor at 100 h Pa is mainly located over the Pacific warm pool region and South America in the equatorial tropics in boreal winter and over the southeast of the South Asian high and south of North America in boreal summer.It is found that temperature averaged over regions with upward transport is a better indicator of interannual variability of tropical mean stratospheric water vapor than the tropical mean temperature.It seems that the distributions of the seasonal cycle amplitude of lower stratospheric water vapor in the tropics can also be impacted by the vertical transport.The radiative effects of the interannual changes in water vapor in the lowermost stratosphere are underestimated by approximately 29%in both ERAI and WACCM compared to MLS,although the interannual variations of water vapor in the lowermost stratosphere are dramatically overestimated in ERAI and WACCM.The results here indicate that the radiative effect of long-term changes in water vapor in the lowermost stratosphere may be underestimated in both ERAI and WACCM simulations.
