Temporal and spatial distribution characteristics of water resources in Guangdong Province based on a cloud model

With a focus on the difficulty of quantitatively describing the degree of nonuniformity of temporal and spatial distributions of water resources, quantitative research was carried out on the temporal and spatial distribution characteristics of water resources in Guangdong Province from 1956 to 2000 based on a cloud model. The spatial variation of the temporal distribution characteristics and the temporal variation of the spatial distribution characteristics were both analyzed. In addition, the relationships between the numerical characteristics of the cloud model of temporal and spatial distributions of water resources and precipitation were also studied. The results show that, using a cloud model, it is possible to intuitively describe the temporal and spatial distribution characteristics of water resources in cloud images. Water resources in Guangdong Province and their temporal and spatial distribution characteristics are differentiated by their geographic locations. Downstream and coastal areas have a larger amount of water resources with greater uniformity and stronger stability in terms of temporal distribution. Regions with more precipitation possess larger amounts of water resources, and years with more precipitation show greater nonuniformity in the spatial distribution of water resources. The correlation between the nonuniformity of the temporal distribution and local precipitation is small, and no correlation is found between the stability of the nonuniformity of the temporal and spatial distributions of water resources and precipitation. The amount of water resources in Guangdong Province shows an increasing trend from 1956 to 2000, the nonuniformity of the spatial distribution of water resources declines, and the stability of the nonuniformity of the spatial distribution of water resources is enhanced.

Numerical modeling calculation for the spatial distribution characteristics of horizontal field transfer functions

Applying 3-dimension finite difference method, the distribution characteristics of horizontal field transfer functions for rectangular conductor have been computed, and the law of distribution for Re-part and Im-part has been given. The influences of source field period, the conductivity, the buried depth and the length of the conductor on the transfer functions were studied. The extrema of transfer functions appear at the center, the four corners and around the edges of conductor, and move with the edges. This feature demonstrates that around the edges are best places for transfer functions' observation.

Spatial Distribution Characteristics and Influencing Factors of Traditional Villages in Northern Guangxi Based on Spatiotemporal Big Data and Spatial Syntax

Public space as an extension of private living spaces carries the different social life and customs of human settlement.To analyze the spatial distribution characteristics of traditional villages in northern Guangxi based on spatial syntax and its influencing factors,this paper analyzed and compared the spatial structure and morphology of traditional villages in northern Guangxi by using the theory of spatial syntax and linguistics as the quantitative analysis method of spatial syntax,and verified the feasibility of expanding the application of spatial syntax,finally,the generality and characteristics of the spatial structure and form of traditional villages in northern Guangxi were put forward.Protection has been implemented.According to the comprehensibility data in this paper,the comprehensibility of the village 1 in northern Guangxi is 0.52,the village 2 is 0.40,the village 3 is 0.35,the village 4 is 0.48,the village 5 is 0.55 and the village 6 is 0.50.It showed that in the selected 6 village samples,except for the 3 ones in northern Guangxi,the local space of the other 3 villages could better perceive the overall space,which also reflected the overall space permeability of most traditional villages in northern Guangxi was good.

Research on Spatial Distribution Characteristics of Bars and Their Influence on Surrounding Residents:A Case Study of Hongling Area in Shenzhen

This paper took the bar space in Hongling area of Shenzhen as the research object,analyzed the relationship between the distribution of bars and urban commercial buildings,traffic stations,residential areas,hotels and guesthouses.It also analyzed the impact of bars on urban residents in terms of noise,crime and traffic congestion.The study found that the location of bars was closely related to urban commercial centers,traffic stations,residential areas,hotels and guesthouses,the occurrence of noise and criminal cases was also highly related to bars;and the distribution of bars had an impact on traffic congestion to a certain extent.

Spatial Distribution Characteristics and Evolution Trends of Urban Aging Population

This paper selects Beijing, Shanghai, Guangzhou, and Wuhan as examples and builds a database based on the statistics of the ? fth and sixth national population censuses and the latest statistics of aging population collected by ministries and commissions of the Central Government and local departments, as well as by our research team from 2000 to 2010. With its data unit accurate to Jiedao~① level, it is the ? rst time to analyze the micro-level spatial distribution characteristics of the aging population in China's mega cities in comparison with research accomplishments in geography, which lays a foundation for further relevant studies and strategy formulation. The paper draws spatial distribution maps of the aging population in Beijing, Shanghai, Guangzhou, and Wuhan by Geograpic Information System(GIS), and uses Aging Degree Index and Population Gravitational Center respectively to analyze the spatial distribution characteristics and spatial evolution trends of aging population in these mega cities. The research indicates that, on the one hand, the spatial distribution of the aging population shows similar characteristics with that of developed countries when they were at the same urbanization level, especially with Japan which shares a cultural homology with China; on the other hand, it is greatly in? uenced by the distribution of af? liated residential space of large industrial sectors, enterprises, and research institutes under the early planned economic system. There are two trends: one is centrifugal spread, namely, the elderly are moving from the city center to the outside; the other is centripetal concentration, namely, the elderly who lived in the outer suburbs are moving towards the city center. These phenomena, such as centripetal concentration, suburban spread, exurban concentration, and socio-spatial differentiation of urban aging population, are driven by selective development in the city center, city function upgrading, re-hollowing of villages, and occupation and income differentiation of the elderly before retirement.

Spatial Distribution Characteristics of Negative Air Ion Concentrations in Danqinghe Experimental Forest,Harbin City

In recent years, air ions, especially of negative air ion has received a universal attention for its health function. The density of negative air ion has become one of the important indexes that measure the air quality grade. With the air ions counter made in Japan, the spatial distribution characteristics of negative air concentrations at specific time in Danqinghe Experimental Forest were measured and studied, Harbin City, and the air quality was assessed by using ion polarity ration (q) and air ion assessment index (CI). The results showed that at a given time, the average concentrations of negative air ions were different for different forest types, stand origins, tree species and different parts of Balan River. There was a clear difference in ion polarity ration and air ion assessment index, and the air quality in different environments were also quite different.

Types, Metallogenic Environments and Characteristics of Temporal and Spatial Distribution of Copper Deposits in China

Based upon a comprehensive study of 123 copper deposits in China. this paper reaches the following conclusions: 1. The crust in China was solidified pretty late; with the accretion of the plate, the copper mineralization moved towards its margin in space and became successively younger in age. 2. The major copper ore types ever found in the world have mostly been discovered in China, in which the porphyry type seems to be the most important and the massive sulfide type in the transitional bed between marine clastic and carbonate rocks is clearly defined. 3. Carbonate strata are widespread in China and their deposition lasted for a long geological period, so the proportion of copper deposits occurring in them is large as compared with other parts of the world. 4. Seven metallogenic epochs can be recognized, in which the Mesozoic one plays the leading role and the middle(late) Palaeozoic and Cenozoic ones are next in importance. Mineralization was comparatively simple in the early geological period. and became diversified later on. In the early epochs copper deposits related to basaltic magmatism and metamorphosed marine sediments predominated, whereas in the later epochs those related to granitic magmatism and continental sedimentation were dominant. 5. There exist in China thirteen metallogenic provinces, of which the Lower Yangtze downwarping belt, Sanjiang fold system, Jiangnan axis and Xikang-Yunnan axis are of greater significance. 6. The crustal mobility in China was rather pronounced, the polycyclic evolution of the crust has resulted in such obvious phenomena as the inheritance of mineralization, the coexistence of various types and the superposition of different genetic types.

Spatial distribution of electron characteristic in argon rf glow discharges

The spatial distributions of the electron density and the mean electron energy of argon radio frequency （rf） glow discharge plasma in a plasma-enhanced chemical vapour deposition （PECVD） system have been investigated using an established movable Langmuir probe. The results indicate that in the axial direction the electron density tends to peak at midway between the two electrodes while the axial variation trend of mean electron energy is different from that of the electron density, the mean electron energy is high near the electrodes. And the mean electron energy near the cathode is much higher than that near the anode. This article focuses on the radial distribution of electron density and mean electron energy. A proposed theoretical model distribution agrees well with the experimental one： the electron density and the mean electron energy both increase from the centre of the glow to the edge of electrodes. This is useful for better understanding the discharge mechanism and searching for a better deposition condition to improve thin film quality.

Spatial and temporal patterns of solar radiation in China from 1957 to 2016

Solar energy is clean and renewable energy that plays an important role in mitigating impacts of environmental problems and climate change.Solar radiation received on the earth's surface determines the efficiency of power generation and the location and layout of photovoltaic arrays.In this paper,the average daily solar radiation of 77 stations in China from 1957 to 2016 was analyzed in terms of spatial and temporal characteristics.The results indicate that Xinjiang,the Qinghai-Tibet Plateau,North,Central and East China show a decreasing trend with an average of 2.54×10^(−3)MJ/(m^(2)⋅10a),while Northwest and Northeast China are basically stabilized,and Southwest China shows a clear increasing trend with an average increase of 1.79×10^(−3)MJ/(m^(2)⋅10a).The average daily solar radiation in summer and winter in China from 1957 to 2016 was 18.74 MJ/m^(2)and 9.09 MJ/m^(2),respectively.Except for spring in Northwest,East and South China,and summer in northeast China,the average daily solar radiation in all other regions show a downward trend.A critical point for the change is 1983 in the average daily solar radiation.Meanwhile,large-scale(25−30 years)oscillation changes are more obvious,while small-scale(5−10 years)changes are stable and have a global scope.The average daily solar radiation shows an increasing-decreasing gradient from west to east,which can be divided into three areas west of 80°E,80°E−100°E and east of 100°E.The average daily solar radiation was 2.07 MJ/m^(2)in the 1980s,and that in 1990s lower than that in the 1960s and the 1970s.The average daily solar radiation has rebounded in the 21st century,but overall it is still lower than the average daily solar radiation from 1957 to 2016(13.87 MJ/m^(2)).

Analysis of the severe group dust storms in eastern part of Northwest China

Based on the available original dust storm records from 60 meteorological stations, we discussed the identification standard of severe dust storms at a single station and constructed a quite complete time series of severe group dust storms in the eastern part of Northwest China in 1954–2001. The result shows that there were 99 severe group dust storms in this region in recent 48 years. The spatial distribution indicates that the Alax Plateau, most parts of the Ordos Plateau and most parts of the Hexi Corridor are the main areas influenced by severe group dust storms. In addition, the season and the month with the most frequent severe group dust storms are spring and April, accounting for 78.8% and 41.4% of the total events respectively. During the past 48 years the lowest rate of severe group dust storms occurred in the 1990s. Compared with the other 4 decades, on the average, the duration and the affected area of severe group dust storms are relatively short and small during the 1990s. In 2000 and 2001, there were separately 4 severe group dust storms as the higher value after 1983 in the eastern part of Northwest China.

Effect of terrain on landscape patterns and ecological effects by a gradient-based RS and GIS analysis

Terrain is an important environment factor that plays a vital role in human development by influencing the spatial layout of land use patterns. The terrain niche index, combined with slope and elevation, can comprehensively present detailed information about spatial differences in terrain and is superior to single terrain factors. We applied remote sensing and geographical information system to terrain gradient, used the non-dimensional distribution index to examine spatial distribution characteristics of various landscape types, and analyzed the ecological effects of landscape were quantitatively on terrain gradients. Eco-environment quality (EEQ) was evaluated using the forestry operation area as the evaluation unit. The spatial distributions in various landscapes were significantly influenced by terrain factors, especially by bodies of water, cropland and residential land. The spatial distribution varied greatly in different terrain gradients for similar landscape types. The areas associated with good, intermediate and poor EEQ were occupied primarily by natural landscape, semi-natural and largely artificial landscapes, respectively.

Surface tidal currents in the open sea area to the east of the Zhoushan Islands measured with high frequency surface wave radar

Based on the quasi-harmonic analysis of 11 d vector ocean currents obtained from two high frequency sur- face wave radars located at Zhujiajian Island and Shengshan Island, the spatial distribution characteristics of surface tidal currents in the open sea area to the east of the Zhoushan Islands of Zhejiang Province, China are studied. The following conclusions are drawn from the analysis： the tidal current pattern in the open sea area to the east of Zhoushan Islands is primarily regular semidiurnal, which is significantly affected by the shallow water constituents. The directions of the major axes of tidal current ellipses of M2 lie approx- imately in the NW-SE direction. With the increasing of distance away from the coast, the directions of the tidal current ellipses gradually shift toward the E-W direction. The tidal currents are mainly reversing cur- rents. The spatial distribution of probable maximum current velocities decreases gradually from northeast to southwest which is basically in accordance with the spatial distribution of measured maximum current velocities. The residual currents near the coast are larger than those far away from the coast. The directions of the residual currents are basically north by east, and the angle to the due north increases gradually with the increasing distance away from the coast. The topography shows a certain impact on the spatial distri- bution of shallow water constituents, the rotation of tidal currents, the probable maximum currents and the residual currents.

中国重要农业文化遗产的空间分布特征及其差异性管理策略

Climate change and rapid urbanization pose significant challenges to the conservation and management of agricultural heritage systems,including decline in agricultural land,loss of labor,and ecosystem degradation.Although existing studies have proposed general strategies with theoretical guidance and specific strategies for particular systems to promote the conservation of agricultural heritage systems,there remains a large knowledge gap in effective and differentiated management strategies at the regional level.This is especially so in China because of the clear regional differences in the natural and socioeconomic conditions of the widely distributed China Nationally Important Agricultural Heritage Systems(China-NIAHS).In this study,we integrated multi-source data and spatial analysis to reveal the distribution characteristics of existing China-NIAHS and proposed differentiated management strategies.Results show that there are four clustering distribution zones of China-NIAHS,i.e.,the northwest clustering zone west of the Heihe-Tengchong Line(ZoneⅠ),the clustering belt with‘Northeast-Hebei-Shandong'as core(ZoneⅡ),the Yangtze River Delta clustering zone(ZoneⅢ),and the Hunan-Chongqing-Yunnan-Guizhou clustering zone(ZoneⅣ).Different management strategies are proposed for the China-NIAHS in each clustering zone.Specifically,ZoneⅠshould focus on maintaining their ecological functions and services,while ZoneⅡshould aim for livelihood supply,sustainable resource use,and ecological protection.For ZoneⅢ,rapid urbanization could become a positive driving force for China-NIAHS conservation through sustainable tourism and reasonable urban zoning.ZoneⅣshould emphasize the mutual support between characteristic product development and the brand effect of the China-NIAHS.These findings will help establish regional and targeted management strategies for China-NIAHS and provide a reference for the conservation of agricultural heritage systems in other countries.

Characteristics of the Regional Meteorological Drought Events in Southwest China During 1960–2010

An objective identifi cation technique for regional extreme events （OITREE） and the daily composite-drought index （CI） at 101 stations in Southwest China （including Sichuan, Yunnan, Guizhou, and Chongqing） are used to detect regional meteorological drought events between 1960 and 2010. Values of the parameters of the OITREE method are determined. A total of 87 drought events are identifi ed, including 9 extreme events. The 2009-2010 drought is the most serious in Southwest China during the past 50 years. The regional meteorological drought events during 1960-2010 generally last for 10-80 days, with the longest being 231 days. Droughts are more common from November to next April, and less common in the remaining months. Droughts occur more often and with greater intensity in Yunnan and southern Sichuan than in other parts of Southwest China. Strong （extreme and severe） regional meteorological drought events can be divided into fi ve types. The southern type has occurred most frequently, and Yunnan is the area most frequently stricken by extreme and severe drought events. The regional meteorological drought events in Southwest China have increased in both frequency and intensity over the study period, and the main reason appears to be a signifi cant decrease in precipitation over this region, but a simultaneous increase in temperature also contributes.

Recognition Algorithm and Risk Assessment of Airport Hotspots

The hotspot recognition algorithm is proposed based on a potential collision in order to study the aircraft taxi conflicts in large airports.The spatial and temporal distribution characteristics of hotspots are analyzed based on the risk assessment model of hotspot constructed in this paper.Firstly,approaches for monitoring of the aerodrome movement were compared.The hotspot recognition algorithm taken into account of whether aircrafts'taxi track has spatial and temporal overlap based on the aerodrome surveillance radar(ASR)data was presented,by identifying the hotspots through analyzing whether the aircrafts'time of entering and exiting the same taxiway is overlap or not,and the heading difference and distance of the two aircrafts satisfy the specified threshold constraint condition.Then,the ASR data were divided into several parts,and then airport hotspots were recognized and the spatial and temporal distribution characteristics were analyzed.The risk assessment model of airport safety hotspots was constructed which is taken into account of the conflict probability and its severity consequence.Finally,based on the risk grade assessment criteria and hotspots'risk value,the risk grade ranking of hotspot in one airport of China was evaluated and designated.According to the result,the spatial and temporal distribution characteristics of airport hotspots were varied with the variation of airport traffic flow and operational mode of runway,which shows that the hotspots have the characteristics of dynamic periodicity and diurnal variation.And the risk assessment results were consistent with experts'opinions and actual operation condition,which verified the rationality of the hotspot recognition algorithm,risk assessment model as well as the risk grade ranking criteria.