[Objective] The experiment aimed to determine the optimum ISSR-PCR reaction system of Picea crassifolia kom. [Method] Picea crassifolia kom. was used as material to select and optimize influencing factors of ISSR-PCR ...[Objective] The experiment aimed to determine the optimum ISSR-PCR reaction system of Picea crassifolia kom. [Method] Picea crassifolia kom. was used as material to select and optimize influencing factors of ISSR-PCR such as Mg2+, dNTPs, Taq DNA polymerase, template DNA, primers, annealing temperature. [Result] The optimum ISSR-PCR reaction system in 20 μl reaction system was consisted of 1 μl 10×buffer, 1.5 mmol/L Mg2+, 0.2 mmol/L dNTPs, 1.0 U Taq DNA polymerase, 40 ng template DNA, 0.6 μmol/L primers. According to gradient test of annealing temperature in optimum ISSR-PCR reaction system of Picea crassifolia kom, it was found that the optimum annealing temperature of UBC 818 was 54.2 ℃ and the annealing temperature was different for different primers.[Conclusion]The construction of ISSR-PCR reaction system provided technical basis for classification of germplasm resources, construction of genetic map, gene mapping of Picea crassifolia kom. through using ISSR technology.展开更多
The Chinese east coastal areas and marginal seas are foggy regions. The development of effective forecasting methods rests upon a comprehensive knowledge of the fog phenomena. This study provides new observations asso...The Chinese east coastal areas and marginal seas are foggy regions. The development of effective forecasting methods rests upon a comprehensive knowledge of the fog phenomena. This study provides new observations associated with the sea togs over the northwestern Yellow Sea by means of L-band radar soundings with a high vertical resolution of 30m. The monthly tem- perature lapse rate, the Richardson Nulnbers, and the humidity show obvious seasonal variations in the lower level of the planetary boundary layer (PBL) that are related to the onset, peak and end of the Yellow Sea fog season. The typical pattern of stratification for the sea fog season in the northwestern Yellow Sea is that a stable layer of about 400 m thick caps a 150 m conditionally unstable layer Besides, the differences between togs and stratus clouds in terms of humidity, turbulence and temperature are analyzed, which is of significance for sea fog forecast and detection by satellites. The thickness of the sea fogs varies in different stages of the fog season, and is associated with the temperature inversion. The numerical simulation proves that the seasonal variations obtained by the radar well represent the situations over the Yellow Sea.展开更多
A stratus-sea fog event that occurred over the Yellow and East China Seas on 3 June 2011 is investigated using observations and a numerical model, with a focus on the effects of background circulation and Sea Surface ...A stratus-sea fog event that occurred over the Yellow and East China Seas on 3 June 2011 is investigated using observations and a numerical model, with a focus on the effects of background circulation and Sea Surface Temperature Front (SSTF) on the transition of stratus into sea fog. Southerly winds of a synoptic high-pressure circulation transport water vapor to the Yellow Sea, creating conditions favorable for sea fog/stratus formation. The subsidence from the high-pressure contributes to the temperature inversion at the top of the stratus. The SSTF forces a secondary circulation within the ABL (Atmospheric Boundary Layer), the sinking branch of which on the cold flank of SSTF helps lower the stratus layer fiLrther to reach the sea surface. The cooling effect over the cold sea surface counteracts the adiabatic warming induced by subsidence. The secondary circulation becomes weak and the fog patches are shrtmk heavily with the smoothed SSTE A conceptual model is proposed for the transition of stratus into sea fog over the Yellow and East China Seas. Finally, the analyses suggest that sea fog frequency will probably decrease due to the weakened SSTF and the reduced subsidence of secondary circulation under global wanning.展开更多
Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation sy...Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation system.However,it is difficult to make an effective evaluation of ventilation system due to the lack of classification criteria with respect to underground metal mine in alpine region.This paper proposes a novel evaluation method called the cloud model-clustering analysis(CMCA).Cloud model(CM)is utilized to process collected data of ventilation system,and they are converted into cloud descriptors by CM.Cloud similarity(CS)based Euclidean distance(ED)is proposed to make clustering analysis of assessed samples.Then the classification of assessed samples will be identified by clustering analysis results.A case study is developed based on CMCA.Evaluation results show that ventilation effectiveness can be well classified.Moreover,CM is used alone to make comparison of evaluation results obtained by CMCA.Then the availability and validity of CMCA is verified.Meanwhile,difference of CS based ED and classical ED is analyzed.Two new clustering analysis methods are introduced to make comparison with CMCA.Then the ability of proposed CMCA to meet evaluation requirements of ventilation system is verified.展开更多
Information on the palaeoenvironm ent from Late Pleistocene to Holocen e in northwestern Yannan Plateau has been deduced from a study of a 28.81m-long core taken from Napahai Lake.The results from Relative Brightness ...Information on the palaeoenvironm ent from Late Pleistocene to Holocen e in northwestern Yannan Plateau has been deduced from a study of a 28.81m-long core taken from Napahai Lake.The results from Relative Brightness In-dex(RBI )as well as those from the lithological analyses of bulk sediments,total organic carbon and granulometric analy-ses have been used to reconstruct the environmental and climatic evoluti on of the area.The ages were provided by three 14 C datings.The record suggested a climate fluctuation between warm-dry a nd cool-wet from ca.57to 32ka B.P.,which led a shallowing and swamping of the l ake.The water level again increased quickly at ca.32ka B.P.,reached it’ s peak during LGM(Last Glacial Maximum,ca.18-20ka B.P.)and remained relative high until ca.15ka B.P.The high wa-ter level at LGM is attributed to cold-wet conditions.The area experienced an abrupt and unstable climatic ch anges dur-ing the transition period from15to 10ka B.P.with a dominated littoral en vironment.Awarm-dry climate led to the contrac-tion of the lake during the Holocene a nd reed-swamps became dominant.After a minor wet-cool pulse during the L ate Holocene,the modern climate became to be established.展开更多
We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the wat...We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the waterbird population. The study was conducted at five selected spots along Lashihai Lake at the same time each week from August 2011 to September 2013. In total, 62 waterbird species were recorded, of which 38.71%, 35.48%, 16.13%, and 9.68% were winter migrants, passage visitors, residents, and summer migrants, respectively. We found important seasonal changes in waterbird species composition and population size. Waterbird species richness was highest from September to the following April, with the total species numbers peaking in December. Total individual numbers peaked twice from late November to early December and mid-to-late February. However, waterbird species and individual numbers were comparatively lower from May to August. The change in species composition was determined by the arrival and departure dynamics of winter migrants and passage visitors. Winter migrants primarily caused the periodic changes in population size. Of concern,species and overall waterbird numbers seemed to be lower than the numbers in historical records. The decline of waterbird numbers implies that environmental changes caused by the implementation of the dam upstream of Lashihai Lake may have had adverse effects on this waterbird population. This study confirms the existence of major seasonal changes in species composition and size of the waterbird population at Lashihai Lake. Furthermore, the findings demonstrate that this wetland is of high conservation importance for waterbirds using the Central Asian–Indian and Asian–Pacific migratory routes.展开更多
Building a cloud geodatabase for a sponge city is crucial to integrate the geospatial information dispersed in various departments for multi-user high concurrent access and retrieval,high scalability and availability,...Building a cloud geodatabase for a sponge city is crucial to integrate the geospatial information dispersed in various departments for multi-user high concurrent access and retrieval,high scalability and availability,efficient storage and management.In this study,Hadoop distributed computing framework,including Hadoop distributed file system and MapReduce(mapper and reducer),is firstly designed with a parallel computing framework to process massive spatial data.Then,access control with a series of standard application programming interfaces for different functions is designed,including spatial data storage layer,cloud geodatabase access layer,spatial data access layer and spatial data analysis layer.Subsequently,a retrieval model is designed,including direct addressing via file name,three-level concurrent retrieval and block data retrieval strategies.Main functions are realised,including real-time concurrent access,high-performance computing,communication,massive data storage,efficient retrieval and scheduling decisions on the multi-scale,multi-source and massive spatial data.Finally,the performance of Hadoop cloud geodatabases is validated and compared with that of the Oracle database.The cloud geodatabase for the sponge city can avoid redundant configuration of personnel,hardware and software,support the data transfer,model debugging and application development,and provide accurate,real-time,virtual,intelligent,reliable,elastically scalable,dynamic and on-demand cloud services of the basic and thematic geographic information for the construction and management of the sponge city.展开更多
The origin and migration of natural gas and the accumulation of gas hydrates within the Pearl River Mouth Basin of the northern South China Sea are poorly understood. Based on high-resolution 2D/3D seismic data, three...The origin and migration of natural gas and the accumulation of gas hydrates within the Pearl River Mouth Basin of the northern South China Sea are poorly understood. Based on high-resolution 2D/3D seismic data, three environments of focused fluid flow: gas chimneys, mud diapirs and active faults have been identified. Widespread gas chimneys that act as important conduits for fluid flow are located below bottom simulating reflections and above basal uplifts. The occurrence and evolution of gas chimneys can be divided into a violent eruptive stage and a quiet seepage stage. For most gas chimneys, the strong eruptions are deduced to have happened during the Dongsha Movement in the latest Miocene, which are observed below Pliocene strata and few active faults develop above the top of the Miocene. The formation pressures of the Baiyun Sag currently are considered to be normal, based on these terms: 1) Borehole pressure tests with pressure coefficients of 1.043-l.047; 2) The distribution of gas chimneys is limited to strata older than the Pliocene; 3) Disseminated methane hydrates, rather than fractured hydrates, are found in the hydrate samples; 4) The gas hydrate is mainly charged with biogenic gas rather than thermogenic gas based on the chemical tests from gas hydrates cores. However, periods of quiet focused fluid flow also enable the establishment of good conduits for the migration of abundant biogenic gas and lesser volumes ofthermogenic gas. A geological model goveming fluid flow has been proposed to interpret the release of overpressure, the migration of fluids and the formation of gas hydrates, in an integrated manner. This model suggests that gas chimneys positioned above basal uplifts were caused by the Dongsha Movement at about 5.5 Ma. Biogenic gas occupies the strata above the base of the middle Miocene and migrates slowly into the gas chimney columns. Some of the biogenic gas and small volumes ofthermogenic gas eventually contribute to the formation of the gas hydrates.展开更多
[Objective] The aim was to analyze the correlation between tree-ring width of Picea crassifolia in the east of Qilian Mountains and the precipitation, temperature and the normalized difference vegetation index (NDVI)....[Objective] The aim was to analyze the correlation between tree-ring width of Picea crassifolia in the east of Qilian Mountains and the precipitation, temperature and the normalized difference vegetation index (NDVI). [Method] The correlation analysis and the regression analysis were used in this study. [Result] The tree-ring width was significantly correlated with the autumn precipitation and the spring average NDVI. The conversion equation between tree-ring width and spring NDVI (R2 = 48.5% , R2adj =46.2% , F =21.627, P <0.001) was developed and NDVI sequence was reconstructed during the period 1915 -2007. The drought in the 1920s was pronounced. Vegetation cover in the Qilian Mountains increased during the period 1922-1934, 1940-1957, 1965-1969, 1984-1988 and 1995-1997, but decreased during 1935 -1939, 1958 -1964, 1970 -1983, 1989 -1994 and 1998 -2005. [Conclusion] The reconstructed NDVI showed the drought evolution in the study area.展开更多
The decomposition of plant litter is a key process of litter decomposition to global climate warming in plateau in the flows of energy and nutrients in ecosystems. However, the response wetlands remains largely unknow...The decomposition of plant litter is a key process of litter decomposition to global climate warming in plateau in the flows of energy and nutrients in ecosystems. However, the response wetlands remains largely unknown. In this study, we conducted a one-year litter decomposition experiment along an elevation gradient from 1891 m to 3260 m on the Yurman Plateau of Southwest China, using different litter types to determine the influences of climate change, litter quality and microenvironment on the decomposition rate. The results showed that the average decomposition rate (K) increased from 0.608 to 1.152, and the temperature sensitivity of litter mass losses was approximately 4.98%/℃ along the declining elevation gradient. Based on a correlation analysis, N concentrations and C : N ratios in the litter were the best predictors of the decomposition rate, with significantly positive and negative correlations, respectively. Additionally, the cumulative effects of decomposition were clearly observed in the mixtures of Scirpus tabernaemontani and Zizania caduciflora. Moreover, the litter decomposition rate in the water was higher than that in the sediment, especially in high-elevation areas where the microenvironment was significantly affected by temperature. These results suggest that future climate warming will have significant impacts on plateau wetlands, which have important fimctions in biogeochemical cycling in cold highland ecosystems.展开更多
Cloud water samples, LWC (Liquid Water Content) and meteorological data were collected at the Clingmans Dome, Tennessee, high-elevation site in Great Smoky Mountains National Park during the warm season from 1994 th...Cloud water samples, LWC (Liquid Water Content) and meteorological data were collected at the Clingmans Dome, Tennessee, high-elevation site in Great Smoky Mountains National Park during the warm season from 1994 through 2011. This paper presents results from 2000 through the conclusion of the study in 2011. Samples were analyzed for SO42", NO3, NH4+ and H+. These measurements were supplemented by measurements of ambient air and precipitation concentrations to estimate dry and wet deposition. Cloud water concentrations, LWC, cloud frequency, various meteorological measurements and information on nearby forest canopy were used to model cloud water deposition to gauge trends in deposition. Total deposition was calculated as the sum of cloud, dry and wet deposition estimates. Concentrations and deposition fluxes declined over the study period. The decreases in cloud water SO42" and NO3 concentrations were 40 percent and 26 percent, respectively. Three-year mean 5042 and NO3 deposition rates decreased by 71 percent and 70 percent, respectively. Trends in concentrations and depositions were comparable with trends in SO2 and NOx emissions from Tennessee Valley Authority power plants and aggregated emission reductions from electric generating units in adjacent states. Back trajectories were simulated with the HYSPLIT model and aggregated over cloud sampling periods from 2000 through 2007 and 2009 through 2011. Trajectories during periods with high H+ concentrations traveled over local EGU (Electric Generating Unit) emission sources in Tennessee and Kentucky to the Ohio River Valley, Alabama and Georgia with the conclusion that these source regions contributed to acidic cloud water deposition at Clingmans Dome. This work was supported by U.S. Environmental Protection Agency and the Tennessee Valley Authority with infrastructure support provided by the National Park Service.展开更多
A Lagrangian advection scheme(LAS)for solving cloud drop diffusion growth was previously proposed(in 2020)and validated with simulations of cloud droplet spectra with a one-and-a-half dimensional(1.5D)cloud bin model ...A Lagrangian advection scheme(LAS)for solving cloud drop diffusion growth was previously proposed(in 2020)and validated with simulations of cloud droplet spectra with a one-and-a-half dimensional(1.5D)cloud bin model for a deep convection case.The simulation results were improved with the new scheme over the original Eulerian scheme.In the present study,the authors simulated rain embryo formation with the LAS for a maritime shallow cumulus cloud case from the RICO(Rain in Cumulus over the Ocean)campaign.The model used to simulate the case was the same 1.5D cloud bin model coupled with the LAS.Comparing the model simulation results with aircraft observation data,the authors conclude that both the general microphysical properties and the detailed cloud droplet spectra are well captured.The LAS is robust and reliable for the simulation of rain embryo formation.展开更多
Flood land, with abundant light, heat, and water resource, is an important potential land resource to resolve the situation of the limited arable land in mountain areas in Xiaojiang Valley, Dongchuan, Yunnan. It will ...Flood land, with abundant light, heat, and water resource, is an important potential land resource to resolve the situation of the limited arable land in mountain areas in Xiaojiang Valley, Dongchuan, Yunnan. It will have a great significance on the development of local characteristic agriculture and the settlement of poor moun- tain immigrants that how to develop and protect the flood land in a scientific, effec- tive and sustainable way. In this paper, flood land of Xiaojiang Valley is divided into three zones (higher zone is 1 600-1 300 m, medium zone is 1 300-1 000 m, low- er zone is 1 000-700 m) according to different elevations. Through field survey, in situ measurement, sampling analysis and "3S" technology, the area and soil nutri- ent characteristics of flood land at different altitudes are tested and analyzed sys- tematically. And also according to the climatic characteristics in different elevations of flood land, the research analyzed and investigated the growing conditions of flood land in different elevations in Xiaojiang Valley, and then discussed how to develop and cultivate reasonably and effectively in flood land. All the work is intended to provide beneficial reference for the development and cultivation of flood land in mountain areas.展开更多
Earthquake and its resultant tsunami, as a kind of disaster events in geological history, may be recorded as event deposits of seismite and tsunamite. Typical characteristics of seismite and tsunamite, including seism...Earthquake and its resultant tsunami, as a kind of disaster events in geological history, may be recorded as event deposits of seismite and tsunamite. Typical characteristics of seismite and tsunamite, including seismo-fracture bed, synsedimentary microfracture, micro-corrugated lamination, molar tooth structure, hummocky bedding, occurs in Mesoproterozoic Dalongkou Formation of Kunyang Group in central Yunnan Province. Three types of sedimentary units have been recognized: seismite (unit-A, including limestone with molar tooth structure, seismic shattering rock, seismic corrugated rock, autoclastic breccia and intraclastic parabreccia), tsunamite (unit-B, intraclastic limestone with hummocky or parallel beddings) and background deposits (unit-C). Various stackings of these units construct three distinct sedimentary sequences: A-B-C, A-C and B-C. A-B-C represents an event sedimentary sequence of earthquake-tsunami-background deposits, A-C represents the sequence of earthquake and background deposits (no tsunami occur-ring), and B-C represents the sequence of tsunami and background deposits (far from the center of earthquake). As the central Yunnan Province was located in a tectonic setting of rift basin in Mesoproterozoic Era, the earthquake event deposits of the Dalongkou Formation are sedimentary response to tectonic activity of the rift basin.展开更多
Based on satellite data and the estimated inversion strength(EIS) derived by Wood et al.(2006), a feasible and uncomplicated stratocumulus scheme is proposed, referred to as EIS scheme. It improves simulation of cloud...Based on satellite data and the estimated inversion strength(EIS) derived by Wood et al.(2006), a feasible and uncomplicated stratocumulus scheme is proposed, referred to as EIS scheme. It improves simulation of cloud radiative forcing(CRF) in the Grid-point Atmospheric Model of IAP/LASG version 2(GAMIL2.0) model. When compared with the original lower troposphere stability(LTS) scheme, the EIS scheme reproduces more reasonable climatology distributions of clouds and CRF. The parameterization partly corrects CRF underestimation at mid and high latitudes and overestimation in the convective region. Such improvements are achieved by neglecting the effect of free-tropospheric stratification changes that follow a cooler moist adiabat at middle and high latitude, thereby improving simulated cloudiness. The EIS scheme also improves simulation of the CRF interannual variability. The positive net CRF and negative stratiform anomaly in the East Asian and western North Pacific monsoon regions(EAWNPMR) are well simulated. The EIS scheme is more sensitive to sea surface temperature anomalies(SSTA) than the LTS. Therefore, under the effect of a warmer SSTA in the EAWNPMR, the EIS generates a stronger negative stratiform response, which reduces radiative heating in the low and mid troposphere, in turn producing strong subsidence and negative anomalies of both moisture and cloudiness. Consequent decreases in cloud reflection and shading effects ultimately improve simulation of incoming surface shortwave radiative fluxes and CRF. Because of the stronger subsidence, a stronger anomalous anticyclone over the Philippines Sea is simulated by the EIS run, which leads to a better positive precipitation anomaly in eastern China during ENSO winter.展开更多
文摘[Objective] The experiment aimed to determine the optimum ISSR-PCR reaction system of Picea crassifolia kom. [Method] Picea crassifolia kom. was used as material to select and optimize influencing factors of ISSR-PCR such as Mg2+, dNTPs, Taq DNA polymerase, template DNA, primers, annealing temperature. [Result] The optimum ISSR-PCR reaction system in 20 μl reaction system was consisted of 1 μl 10×buffer, 1.5 mmol/L Mg2+, 0.2 mmol/L dNTPs, 1.0 U Taq DNA polymerase, 40 ng template DNA, 0.6 μmol/L primers. According to gradient test of annealing temperature in optimum ISSR-PCR reaction system of Picea crassifolia kom, it was found that the optimum annealing temperature of UBC 818 was 54.2 ℃ and the annealing temperature was different for different primers.[Conclusion]The construction of ISSR-PCR reaction system provided technical basis for classification of germplasm resources, construction of genetic map, gene mapping of Picea crassifolia kom. through using ISSR technology.
基金the National Scientific and Technological R&D Program Nos 2006AA09Z149,GYHY200706031the Scientific and Technological R&D Program of Qingdao No05-2-NS-35
文摘The Chinese east coastal areas and marginal seas are foggy regions. The development of effective forecasting methods rests upon a comprehensive knowledge of the fog phenomena. This study provides new observations associated with the sea togs over the northwestern Yellow Sea by means of L-band radar soundings with a high vertical resolution of 30m. The monthly tem- perature lapse rate, the Richardson Nulnbers, and the humidity show obvious seasonal variations in the lower level of the planetary boundary layer (PBL) that are related to the onset, peak and end of the Yellow Sea fog season. The typical pattern of stratification for the sea fog season in the northwestern Yellow Sea is that a stable layer of about 400 m thick caps a 150 m conditionally unstable layer Besides, the differences between togs and stratus clouds in terms of humidity, turbulence and temperature are analyzed, which is of significance for sea fog forecast and detection by satellites. The thickness of the sea fogs varies in different stages of the fog season, and is associated with the temperature inversion. The numerical simulation proves that the seasonal variations obtained by the radar well represent the situations over the Yellow Sea.
文摘A stratus-sea fog event that occurred over the Yellow and East China Seas on 3 June 2011 is investigated using observations and a numerical model, with a focus on the effects of background circulation and Sea Surface Temperature Front (SSTF) on the transition of stratus into sea fog. Southerly winds of a synoptic high-pressure circulation transport water vapor to the Yellow Sea, creating conditions favorable for sea fog/stratus formation. The subsidence from the high-pressure contributes to the temperature inversion at the top of the stratus. The SSTF forces a secondary circulation within the ABL (Atmospheric Boundary Layer), the sinking branch of which on the cold flank of SSTF helps lower the stratus layer fiLrther to reach the sea surface. The cooling effect over the cold sea surface counteracts the adiabatic warming induced by subsidence. The secondary circulation becomes weak and the fog patches are shrtmk heavily with the smoothed SSTE A conceptual model is proposed for the transition of stratus into sea fog over the Yellow and East China Seas. Finally, the analyses suggest that sea fog frequency will probably decrease due to the weakened SSTF and the reduced subsidence of secondary circulation under global wanning.
基金Project(2018YFC0808404)supported by National Key Research and Development Program of China。
文摘Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation system.However,it is difficult to make an effective evaluation of ventilation system due to the lack of classification criteria with respect to underground metal mine in alpine region.This paper proposes a novel evaluation method called the cloud model-clustering analysis(CMCA).Cloud model(CM)is utilized to process collected data of ventilation system,and they are converted into cloud descriptors by CM.Cloud similarity(CS)based Euclidean distance(ED)is proposed to make clustering analysis of assessed samples.Then the classification of assessed samples will be identified by clustering analysis results.A case study is developed based on CMCA.Evaluation results show that ventilation effectiveness can be well classified.Moreover,CM is used alone to make comparison of evaluation results obtained by CMCA.Then the availability and validity of CMCA is verified.Meanwhile,difference of CS based ED and classical ED is analyzed.Two new clustering analysis methods are introduced to make comparison with CMCA.Then the ability of proposed CMCA to meet evaluation requirements of ventilation system is verified.
文摘Information on the palaeoenvironm ent from Late Pleistocene to Holocen e in northwestern Yannan Plateau has been deduced from a study of a 28.81m-long core taken from Napahai Lake.The results from Relative Brightness In-dex(RBI )as well as those from the lithological analyses of bulk sediments,total organic carbon and granulometric analy-ses have been used to reconstruct the environmental and climatic evoluti on of the area.The ages were provided by three 14 C datings.The record suggested a climate fluctuation between warm-dry a nd cool-wet from ca.57to 32ka B.P.,which led a shallowing and swamping of the l ake.The water level again increased quickly at ca.32ka B.P.,reached it’ s peak during LGM(Last Glacial Maximum,ca.18-20ka B.P.)and remained relative high until ca.15ka B.P.The high wa-ter level at LGM is attributed to cold-wet conditions.The area experienced an abrupt and unstable climatic ch anges dur-ing the transition period from15to 10ka B.P.with a dominated littoral en vironment.Awarm-dry climate led to the contrac-tion of the lake during the Holocene a nd reed-swamps became dominant.After a minor wet-cool pulse during the L ate Holocene,the modern climate became to be established.
基金funded by the“Technology Supporting Programme” of the “State Wetland Conservation Project for Lashihai Wetland”
文摘We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the waterbird population. The study was conducted at five selected spots along Lashihai Lake at the same time each week from August 2011 to September 2013. In total, 62 waterbird species were recorded, of which 38.71%, 35.48%, 16.13%, and 9.68% were winter migrants, passage visitors, residents, and summer migrants, respectively. We found important seasonal changes in waterbird species composition and population size. Waterbird species richness was highest from September to the following April, with the total species numbers peaking in December. Total individual numbers peaked twice from late November to early December and mid-to-late February. However, waterbird species and individual numbers were comparatively lower from May to August. The change in species composition was determined by the arrival and departure dynamics of winter migrants and passage visitors. Winter migrants primarily caused the periodic changes in population size. Of concern,species and overall waterbird numbers seemed to be lower than the numbers in historical records. The decline of waterbird numbers implies that environmental changes caused by the implementation of the dam upstream of Lashihai Lake may have had adverse effects on this waterbird population. This study confirms the existence of major seasonal changes in species composition and size of the waterbird population at Lashihai Lake. Furthermore, the findings demonstrate that this wetland is of high conservation importance for waterbirds using the Central Asian–Indian and Asian–Pacific migratory routes.
基金Project(NZ1628)supported by the Natural Science Foundation of Ningxia,China
文摘Building a cloud geodatabase for a sponge city is crucial to integrate the geospatial information dispersed in various departments for multi-user high concurrent access and retrieval,high scalability and availability,efficient storage and management.In this study,Hadoop distributed computing framework,including Hadoop distributed file system and MapReduce(mapper and reducer),is firstly designed with a parallel computing framework to process massive spatial data.Then,access control with a series of standard application programming interfaces for different functions is designed,including spatial data storage layer,cloud geodatabase access layer,spatial data access layer and spatial data analysis layer.Subsequently,a retrieval model is designed,including direct addressing via file name,three-level concurrent retrieval and block data retrieval strategies.Main functions are realised,including real-time concurrent access,high-performance computing,communication,massive data storage,efficient retrieval and scheduling decisions on the multi-scale,multi-source and massive spatial data.Finally,the performance of Hadoop cloud geodatabases is validated and compared with that of the Oracle database.The cloud geodatabase for the sponge city can avoid redundant configuration of personnel,hardware and software,support the data transfer,model debugging and application development,and provide accurate,real-time,virtual,intelligent,reliable,elastically scalable,dynamic and on-demand cloud services of the basic and thematic geographic information for the construction and management of the sponge city.
基金Supported by the National Natural Science Foundation of China (Nos.40930845 and 41006031)the International Science & Technology Cooperation Program of China (No. 2010DFA21740)the National Science and Technology Major Project (No. 2011ZX05026-004-06)
文摘The origin and migration of natural gas and the accumulation of gas hydrates within the Pearl River Mouth Basin of the northern South China Sea are poorly understood. Based on high-resolution 2D/3D seismic data, three environments of focused fluid flow: gas chimneys, mud diapirs and active faults have been identified. Widespread gas chimneys that act as important conduits for fluid flow are located below bottom simulating reflections and above basal uplifts. The occurrence and evolution of gas chimneys can be divided into a violent eruptive stage and a quiet seepage stage. For most gas chimneys, the strong eruptions are deduced to have happened during the Dongsha Movement in the latest Miocene, which are observed below Pliocene strata and few active faults develop above the top of the Miocene. The formation pressures of the Baiyun Sag currently are considered to be normal, based on these terms: 1) Borehole pressure tests with pressure coefficients of 1.043-l.047; 2) The distribution of gas chimneys is limited to strata older than the Pliocene; 3) Disseminated methane hydrates, rather than fractured hydrates, are found in the hydrate samples; 4) The gas hydrate is mainly charged with biogenic gas rather than thermogenic gas based on the chemical tests from gas hydrates cores. However, periods of quiet focused fluid flow also enable the establishment of good conduits for the migration of abundant biogenic gas and lesser volumes ofthermogenic gas. A geological model goveming fluid flow has been proposed to interpret the release of overpressure, the migration of fluids and the formation of gas hydrates, in an integrated manner. This model suggests that gas chimneys positioned above basal uplifts were caused by the Dongsha Movement at about 5.5 Ma. Biogenic gas occupies the strata above the base of the middle Miocene and migrates slowly into the gas chimney columns. Some of the biogenic gas and small volumes ofthermogenic gas eventually contribute to the formation of the gas hydrates.
基金Supported by the NSFC(41071128 and 40801004)the Key Program of Hebei Education Department(ZH2012035)
文摘[Objective] The aim was to analyze the correlation between tree-ring width of Picea crassifolia in the east of Qilian Mountains and the precipitation, temperature and the normalized difference vegetation index (NDVI). [Method] The correlation analysis and the regression analysis were used in this study. [Result] The tree-ring width was significantly correlated with the autumn precipitation and the spring average NDVI. The conversion equation between tree-ring width and spring NDVI (R2 = 48.5% , R2adj =46.2% , F =21.627, P <0.001) was developed and NDVI sequence was reconstructed during the period 1915 -2007. The drought in the 1920s was pronounced. Vegetation cover in the Qilian Mountains increased during the period 1922-1934, 1940-1957, 1965-1969, 1984-1988 and 1995-1997, but decreased during 1935 -1939, 1958 -1964, 1970 -1983, 1989 -1994 and 1998 -2005. [Conclusion] The reconstructed NDVI showed the drought evolution in the study area.
基金Under the auspices of Special Projects of National Key Basic Research Program of China(No.2012CB426509)National Natural Science Foundation of China(No.40971285,31370497,31500409)Yunnan Innovation Talents of Science and Technology Plan of China(No.2012HC007)
文摘The decomposition of plant litter is a key process of litter decomposition to global climate warming in plateau in the flows of energy and nutrients in ecosystems. However, the response wetlands remains largely unknown. In this study, we conducted a one-year litter decomposition experiment along an elevation gradient from 1891 m to 3260 m on the Yurman Plateau of Southwest China, using different litter types to determine the influences of climate change, litter quality and microenvironment on the decomposition rate. The results showed that the average decomposition rate (K) increased from 0.608 to 1.152, and the temperature sensitivity of litter mass losses was approximately 4.98%/℃ along the declining elevation gradient. Based on a correlation analysis, N concentrations and C : N ratios in the litter were the best predictors of the decomposition rate, with significantly positive and negative correlations, respectively. Additionally, the cumulative effects of decomposition were clearly observed in the mixtures of Scirpus tabernaemontani and Zizania caduciflora. Moreover, the litter decomposition rate in the water was higher than that in the sediment, especially in high-elevation areas where the microenvironment was significantly affected by temperature. These results suggest that future climate warming will have significant impacts on plateau wetlands, which have important fimctions in biogeochemical cycling in cold highland ecosystems.
文摘Cloud water samples, LWC (Liquid Water Content) and meteorological data were collected at the Clingmans Dome, Tennessee, high-elevation site in Great Smoky Mountains National Park during the warm season from 1994 through 2011. This paper presents results from 2000 through the conclusion of the study in 2011. Samples were analyzed for SO42", NO3, NH4+ and H+. These measurements were supplemented by measurements of ambient air and precipitation concentrations to estimate dry and wet deposition. Cloud water concentrations, LWC, cloud frequency, various meteorological measurements and information on nearby forest canopy were used to model cloud water deposition to gauge trends in deposition. Total deposition was calculated as the sum of cloud, dry and wet deposition estimates. Concentrations and deposition fluxes declined over the study period. The decreases in cloud water SO42" and NO3 concentrations were 40 percent and 26 percent, respectively. Three-year mean 5042 and NO3 deposition rates decreased by 71 percent and 70 percent, respectively. Trends in concentrations and depositions were comparable with trends in SO2 and NOx emissions from Tennessee Valley Authority power plants and aggregated emission reductions from electric generating units in adjacent states. Back trajectories were simulated with the HYSPLIT model and aggregated over cloud sampling periods from 2000 through 2007 and 2009 through 2011. Trajectories during periods with high H+ concentrations traveled over local EGU (Electric Generating Unit) emission sources in Tennessee and Kentucky to the Ohio River Valley, Alabama and Georgia with the conclusion that these source regions contributed to acidic cloud water deposition at Clingmans Dome. This work was supported by U.S. Environmental Protection Agency and the Tennessee Valley Authority with infrastructure support provided by the National Park Service.
基金This research was funded by the National Natural Science Foundation of China[grant number 41705119]a basic research project[grant number xxx0109-301].
文摘A Lagrangian advection scheme(LAS)for solving cloud drop diffusion growth was previously proposed(in 2020)and validated with simulations of cloud droplet spectra with a one-and-a-half dimensional(1.5D)cloud bin model for a deep convection case.The simulation results were improved with the new scheme over the original Eulerian scheme.In the present study,the authors simulated rain embryo formation with the LAS for a maritime shallow cumulus cloud case from the RICO(Rain in Cumulus over the Ocean)campaign.The model used to simulate the case was the same 1.5D cloud bin model coupled with the LAS.Comparing the model simulation results with aircraft observation data,the authors conclude that both the general microphysical properties and the detailed cloud droplet spectra are well captured.The LAS is robust and reliable for the simulation of rain embryo formation.
基金Supported by National Technology R&D Program(0BAC06B02)~~
文摘Flood land, with abundant light, heat, and water resource, is an important potential land resource to resolve the situation of the limited arable land in mountain areas in Xiaojiang Valley, Dongchuan, Yunnan. It will have a great significance on the development of local characteristic agriculture and the settlement of poor moun- tain immigrants that how to develop and protect the flood land in a scientific, effec- tive and sustainable way. In this paper, flood land of Xiaojiang Valley is divided into three zones (higher zone is 1 600-1 300 m, medium zone is 1 300-1 000 m, low- er zone is 1 000-700 m) according to different elevations. Through field survey, in situ measurement, sampling analysis and "3S" technology, the area and soil nutri- ent characteristics of flood land at different altitudes are tested and analyzed sys- tematically. And also according to the climatic characteristics in different elevations of flood land, the research analyzed and investigated the growing conditions of flood land in different elevations in Xiaojiang Valley, and then discussed how to develop and cultivate reasonably and effectively in flood land. All the work is intended to provide beneficial reference for the development and cultivation of flood land in mountain areas.
基金the "SSER" and the Ministry of Science and Technology of China (Grant No. 95-special-04).
文摘Earthquake and its resultant tsunami, as a kind of disaster events in geological history, may be recorded as event deposits of seismite and tsunamite. Typical characteristics of seismite and tsunamite, including seismo-fracture bed, synsedimentary microfracture, micro-corrugated lamination, molar tooth structure, hummocky bedding, occurs in Mesoproterozoic Dalongkou Formation of Kunyang Group in central Yunnan Province. Three types of sedimentary units have been recognized: seismite (unit-A, including limestone with molar tooth structure, seismic shattering rock, seismic corrugated rock, autoclastic breccia and intraclastic parabreccia), tsunamite (unit-B, intraclastic limestone with hummocky or parallel beddings) and background deposits (unit-C). Various stackings of these units construct three distinct sedimentary sequences: A-B-C, A-C and B-C. A-B-C represents an event sedimentary sequence of earthquake-tsunami-background deposits, A-C represents the sequence of earthquake and background deposits (no tsunami occur-ring), and B-C represents the sequence of tsunami and background deposits (far from the center of earthquake). As the central Yunnan Province was located in a tectonic setting of rift basin in Mesoproterozoic Era, the earthquake event deposits of the Dalongkou Formation are sedimentary response to tectonic activity of the rift basin.
基金supported by the National Natural Science Foundation of China(Grant No.41125017)the National Basic Research Program of China(Grant No.2010CB951904)
文摘Based on satellite data and the estimated inversion strength(EIS) derived by Wood et al.(2006), a feasible and uncomplicated stratocumulus scheme is proposed, referred to as EIS scheme. It improves simulation of cloud radiative forcing(CRF) in the Grid-point Atmospheric Model of IAP/LASG version 2(GAMIL2.0) model. When compared with the original lower troposphere stability(LTS) scheme, the EIS scheme reproduces more reasonable climatology distributions of clouds and CRF. The parameterization partly corrects CRF underestimation at mid and high latitudes and overestimation in the convective region. Such improvements are achieved by neglecting the effect of free-tropospheric stratification changes that follow a cooler moist adiabat at middle and high latitude, thereby improving simulated cloudiness. The EIS scheme also improves simulation of the CRF interannual variability. The positive net CRF and negative stratiform anomaly in the East Asian and western North Pacific monsoon regions(EAWNPMR) are well simulated. The EIS scheme is more sensitive to sea surface temperature anomalies(SSTA) than the LTS. Therefore, under the effect of a warmer SSTA in the EAWNPMR, the EIS generates a stronger negative stratiform response, which reduces radiative heating in the low and mid troposphere, in turn producing strong subsidence and negative anomalies of both moisture and cloudiness. Consequent decreases in cloud reflection and shading effects ultimately improve simulation of incoming surface shortwave radiative fluxes and CRF. Because of the stronger subsidence, a stronger anomalous anticyclone over the Philippines Sea is simulated by the EIS run, which leads to a better positive precipitation anomaly in eastern China during ENSO winter.