中国入境旅游的经济增长效应与空间差异性研究

在旅游业与经济增长作用关系分析基础上,探究了旅游溢出理论,将其产生机制归纳为知识溢出、市场溢出和竞争效应3个方面。实证分析中,构建了包括入境旅游、物质资本、人力资本、科技创新和对外开放的分析框架,运用中国大陆31个省域2000~2014年面板数据对入境旅游的经济增长效应进行实证检验。全局分析得出中国入境旅游在邻近省市以集聚与合作为主,邻近省域入境旅游发展对本地经济增长具有辐射带动作用,且这种空间溢出效应大于直接效应;入境旅游业发达的地区,入境旅游的经济增长效应更大。局部分析发现,随着入境旅游的发展,入境旅游的经济增长效应不断强化,中部部分地区提升幅度最大;入境旅游的经济增长效应存在空间差异性,东部沿海地区贡献最大,西北地区相对最小。     

A discrete global grid system for earth system modeling

To support Earth system modeling, we propose a discrete global grid system that expresses multi-resolution spatial data. Specifically, a unified coding model that expresses a grid of nodes, edges, and cells is constructed for a triangular discrete global grid system. To fulfill the requirements of practical applications, we design a code-based topological query method for this grid system and an algorithm to transform between grid codes and geographic coordinates. We evaluate the Global Finite Volume Community Ocean Model (Global-FVCOM) on the triangular discrete global grid system in the proposed uniform coding model. The ocean tidal waves simulated by the Global-FVCOM running on the coded grid are then compared with results obtained using a traditional irregular spherical grid system, and the results display comparable accuracy. The uniform coding model proposed in this paper provides a triangular discrete global grid system that can represent multi-resolution spatial data and can be used in Earth system models. This unified coding model can also be applied to the geographic coordinate system made up of latitudes and longitudes, as well as diamond and hexagonal grids.     

Characteristics of high arsenic groundwater in Hetao Basin, Inner Mongolia, northern China

It is well known that the Hetao Basin is one of the most seriously arsenic-affected groundwater areas in China. In order to understand the characteristics of high arsenic(As) groundwater in the Basin, a brief overview of arsenic in groundwater follows. High arsenic in the Basin commonly occurs in shallow groundwater and the total arsenic concentrations range from 0.58 to 572 μg/L(average 99.73 μg/L), exceeding the maximum mandated value of 10 μg/L for drinking water in China; As(Ш) is the predominant species. The regional distribution pattern of arsenic in the groundwater increases from south/southeast to north/northwest. Hangjinhouqi and Wuyuan counties are considered as the most seriously affected areas, with high incidences of endemic arsenicosic diseases in the Hetao Basin. High groundwater arsenic correlates with the increase of well depth. Previous studies proposed that groundwater arsenic in the Basin is mainly originated from desorption of some natural solid materials in the sediments, under reducing condition. Generally, reducing condition is believed to be the primary factor for arsenic releasing from the sediment to groundwater in the region. Under inorganic or bacterial processes, Fe2O3 changes to Fe S and arsenic adsorbed to Fe(OH)3 dissolves into groundwater, and As(V) is reduced to As(Ш). Besides, reducing environments, groundwater hydraulic gradients, organic matter, p H, evapotranspiration, and soil texture are presumed to be the predominant factors that control arsenic mobilization.     

地铁对服务业集聚的影响 ——以广州市为例

以广州市为例,基于POI数据,运用SAR模型识别城市地铁开通对服务业集聚的影响.研究发现:服务业集聚具有显著的空间依赖性特征,本地服务业集聚会受到周边地区服务业集聚的影响;开通地铁对广州市服务业空间集聚产生显著的正向影响,可提高城区的服务业集聚水平,但这种集聚效应因行业不同而有所差异;地铁开通对批发与零售业、住宿与餐饮...     

The Dynamical Influence of Land－Sea Contrast and Sea Surface Temperature on Intraseasonal Oscillation in Tropical Atmosphere

An equatorial β-plane model which includes realistic non-uniform land-sea contrast and the underlying surface temperature distribution is used to simulate the 30-60 day oscillation (LFO) processes in tropical atmosphere, with emphasis on its longitude-dependent evolution and convective seesaw between Indian and the western Pacific oceans.The model simulated the twice-amplification of the disturbances over Indian and the western Pacific oceans while they are travelling eastward. It reproduced the dipole structure caused by the out-of-phase oscillation of the active centres in these two areas and the periodical transition between the phases of LFO. It is suggested that the convective seesaw is the result of interaction of the internal dynamics of tropical atmosphere with the zonally non-uniform thermal forcing from underlying surface. The convective activities are suppressed over Indonesia mari-time continents whilst they are favoured over the Indian Ocean and western Pacific warm waters, so there formed two active oscillation centres. The feedback of convection with large-scale flow slows down the propagation of disturb-ances when they are intensifying over these two areas, therefore they manifest a kind of quasi-stationary component to favor the ‘dipole’ structure. Whereas the disturbances weaken and speed up over the eastern Pacific cold water re-gion due to the interaction of sensible heating and evaporation with perturbational wind. Therefore the two major centers just show out-of-phase oscillation during onecycle around the latitudinal beltBy introducing the SST anomalies in El Ni?o and La Ni?a years into the surface temperature, we also show that they have significant influence on LFO processes. In an anomalously warm year, the LFO disturbances dissipate more slowly over the central-eastern Pacific region and can travel farther eastward; whilst in an anomalously cold year, the opposite is true.     

正压无辐散模式中双涡的相互作用

本文在无环境流场的情况下,利用正压无辐散模式对双涡的相互作用以及β效应的影响进行了数值模拟研究。一系列的试验结果表明:双涡的相对运动对双涡间的初始距离及双涡的相对强度是十分敏感的,双涡间的非线性涡度平流可导致两个系统的气旋隆互旋;同时可造成两个系统的相互吸引和合并或相互排斥,吸引或排斥的临界距离取决于双涡的结构及相对强度:"合并"的快慢取决于双涡的联合强度,联合强度越强越难于"合并"β效应对双涡的相互作用具有显著的影响。它可以改变双涡相互吸引或排斥的性质,还可以使两个相互吸引的同等强度的涡旋"合并"后较平直地向西北方向漂移,而使两个不同强度的涡旋"合并"后的运动表现为β漂移和陀螺运动的叠加。      

大气中微量气体的红外吸收

文章介绍了测定大气中微量气体CO2与CH4透过率的试验。所用的主要设备是FTIR分光计及可变光程吸收池。文中叙述了主要实验结果与数据处理方法，同时用FASCODE-2程序计算了对应实验条件下CO2与CH4的透过率，并与实验结果作了比较。     

ON THE VERTICAL DISCRETIZATION OF ATMOSPHERIC MODELS-PART Ⅰ:EXISTING PROBLEMS,DATA PROCESSING AND CHOICE OF VERTICAL COORDINATE AND BASIS FUNCTIONS

Discussions are carried out on the vertical discretization of current atmospheric models.It is pointed out that there exist problems in the integration of the hydrostatic equation and the computation of vertical advection,vertical diffusion and so on.Then some possible ways for solving or alleviating them are suggested.Finally,the choice of vertical coordinate and basis functions is discussed.     

金沙江下游云南小江流域山地灾害综合区划

在分别完成云南小江流域泥石流危险度区划、滑坡危险度区划和土壤侵蚀强度分区的基础上,对小江流域山地灾害进行综合区划。结果为,共分为三个不同等级的山地灾害综合区:(1)一级(高危险度)山地灾害综合区,(2)二级(次高危险度)山地灾害综合区和(3)四级(低危险度)山地灾害综合区;无三级(中危险度)山地灾害综合区。其中一级(高危险度)区面积1 425.34 km2,有泥石流沟84条,占区划区域泥石流沟总数的60.0%,有滑坡137个,占区划区域滑坡总数的77.4%,土壤侵蚀强度以轻、中度为主;二级(次高危险度)区面积756.79 km2,有泥石流沟35条,占区划区域泥石流沟总数的25.0%,有滑坡34个,占区划区域滑坡总数的19.2%,土壤侵蚀以轻、中度为主;四级(低危险度)区面积863.20 km2,有泥石流沟21条,占区划区域泥石流沟总数的15.0%,有滑坡6个,占区划区域滑坡总数的3.4%,土壤侵蚀以轻度为主。