江西省交通区位演变与区域发展效应

选择江西省作为典型研究区域,采用历史分析与空间分析方法,基于长时间序列研究不同交通运输阶段交通区位的动态演变过程,并对其所引致的区域发展特征进行分析.结论是:在传统交通运输阶段向近代化及现代化交通运输阶段转变过程中,江西省宏观交通区位分别表现为国家南北交通控扼中枢,铁路建设的滞后区与周边发达地区间的交通过境区,可达性演变特征则由南北方向可达性的优势区逐步演化为滞后区.不同时期相对应的区域发展特征表现为,从传统运输阶段的区域商贸全面繁荣,走向近代工业化进程滞后及当前经济发展边缘化.在总结典型案例基础上,尝试从成因层,演变层,作用层,效应层和反馈层五个层面探讨交通区位与区域发展的内在作用关系.     

黄河源径流演变特征及其对降水的响应

采用1960-2012年黄河源径流、降水数据,以过程线法、集中度和集中期等方法分析黄河沿以上、黄河沿-吉迈、吉迈-玛曲、玛曲-唐乃亥等4个区段降水、径流的演变特征,并从降水的产流能力、时滞相关和集中期响应等角度分析径流对降水的响应。结果表明：黄河源径流汛期占比年际变化趋势自上游各区段呈不显著的增加-减少-增加-减少的特征。吉迈以上径流量年际变化呈不显著增加,吉迈以下呈减少趋势。各区段径流集中期均有不同程度的提前。下游径流集中期早于上游。黄河源汛期降水占比呈不显著下降趋势。4个区段自上游降水年际变化呈显著增加-显著增加-不显著减少-不显著增加的特征。降水的集中度分布较径流更为集中,且有不显著减少趋势。各区段降水的产流能力在20世纪80年代末至90年代中期出现弱化趋势,中上游在2005年左右降水的产流能力转为较分析时段初期有增强的趋势,而中下游一直较分析时段初期减小。不同区段年径流量与不同统计时段降水量的依存关系不同。黄河源玛曲以上径流相对于降水的集中期滞后天数呈不显著减少,玛曲-唐乃亥滞后天数略有增加。     

Effects of land use and cultivation time on soil organic and inorganic carbon storage in deep soils

The vertical distribution and exchange mechanisms of soil organic and inorganic carbon(SOC, SIC) play an important role in assessing carbon(C) cycling and budgets. However, the impact of land use through time for deep soil C(below 100 cm) is not well known. To investigate deep C storage under different land uses and evaluate how it changes with time, we collected soil samples to a depth of 500 cm in a soil profile in the Gutun watershed on the Chinese Loess Plateau(CLP); and determined SOC, SIC, and bulk density. The magnitude of SOC stocks in the 0–500 cm depth range fell into the following ranking: shrubland(17.2 kg m~(-2)) grassland(16.3 kg m~(-2)) forestland(15.2 kg m~(-2)) cropland(14.1 kg m~(-2)) gully land(6.4 kg m~(-2)). The ranking for SIC stocks were: grassland(104.1 kg m~(-2)) forestland(96.2 kg m~(-2)) shrubland(90.6 kg m~(-2)) cropland(82.4 kg m~(-2)) gully land(50.3 kg m~(-2)). Respective SOC and SIC stocks were at least 1.6-and 2.1-fold higher within the 100–500 cm depth range, as compared to the 0–100 cm depth range. Overall SOC and SIC stocks decreased significantly from the 5 th to the 15 th year of cultivation in croplands, and generally increased up to the 70 th year. Both SOC and SIC stocks showed a turning point at 15 years cultivation, which should be considered when evaluating soil C sequestration. Estimates of C stocks greatly depends on soil sampling depth, and understanding the influences of land use and time will improve soil productivity and conservation in regions with deep soils.     

近百余年上海气温变化的若干特征

本文根据1873—1990年上海的年、冬、夏平均气温资料,并利用1956—1990年其郊区气温资料,对城市热岛效应对气温的影响作了处理,重建了近118a的上海气温序列。在此基础上对上海的气温变化特征进行分析,并与同期的北半球气温变化作了比较。结果表明,上海的气温变化有其明显的阶段性、跃变性和周期性。近百余年上海气温变化的总体特征与北半球相似,呈缓慢变暖趋势,但具体的变化过程和幅度有差别,尤其近20多年来的变化与北半球不一致,没有明显的增温现象。     

闲暇时间约束对中山陵景区国内客源市场空间结构的影响

闲暇时间是旅游需求得以实现的必要条件之一,居民闲暇时间的变化必然对旅游地客源市场空间结构产生影响。选择"五一"小长假、"十一"黄金周及暑假3类6个不同闲暇时长的时段,基于现场问卷调研,使用客源地地理集中指数、客源吸引半径、距离衰减曲线及引力模型研究闲暇时间约束对南京市中山陵景区客源市场空间结构的影响,发现随着假日时长的增加,居民出游距离受闲暇时间的约束降低,从而旅游地客源吸引半径增大,客源地集中指数降低、距离衰减曲线变缓、距离衰减指数降低。研究结果表明,在不同时长的闲暇时间约束下,距离因素对景区客流量的影响最大,其次为收入(客源地人均地区生产总值),而客源地人口规模因素的影响最小。     

基于水库调蓄的黄河干流水体交换时间研究(英文)

This note analyzes the change in water renewal time characteristics based on res-ervoir action and then establishes calculation models for the water renewal time in the Yellow River mainstream. The results indicate that the amount of renewable water with reservoir action can meet the annual water demand and that water flows naturally at the Lijin station near estuary. Initial storage dynamics is an important factor in water resource renewable capacity at a certain time, and rational reservoir action can promote sustainable water re-source utilization. When the initial storages in the Longyang Gorge reservoir are 9.343 and 5.343 billion m3, the water renewal times are 28 and 33.9 d, respectively. Flow stoppage ap-pears in April and May.     

Spatio-temporal analysis of tree height in a young cork oak plantation

Cork oak is one of the most valuable natural forest genera in the Mediterranean basin. Modelling cork oak growth has been a challenge for foresters in recent years because of strong site and genetic influences, below-ground competition, management regimes and age effects. Because cork productivity is related to forest height, which is, in turn, related directly with site characteristics, an increase in the accuracy of height prediction implies improved productivity estimation. A Bayesian maximum entropy (BME) geostatistical model was applied to characterize the space–time pattern of height of young cork oak in a forest stand from central Sardinia in the years 2000, 2002, 2003, 2006 and 2008. Cork oak height maps were produced for each of the 5 years. The main goals were to analyse and interpret through time (i) the changes in spatial correlation and (ii) the changes in spatial distribution of cork oak height. The plantation was characterized by an increasing spatial dependence through time, whereas the temporal range was 2 years. Cork oak height was significantly correlated with wind speed (reduced by a neighbouring forest) in all the years implying a single trend. The correlations were larger for 2006 and 2008 than for previous years. Three other environmental variables (shade, elevation and slope) were less significant and their influence restricted to 2 years only. This research has several implications for the management of cork oak in the young phase.     

Exploring space–time paths in physical and social closeness spaces: a space–time GIS approach

Exploring the evolution of people’s social interactions along with their changing physical locations can help to achieve a better understanding of the processes that generate the relationships between physical distance and social interactions, which can benefit broad fields of study related to social networks. However, few studies have examined the evolving relationships between physical movements and social closeness evolution. This is partially related to the shortage of longitudinal data in both physical locations and social interactions and the lack of an exploratory analysis environment capable of effectively investigating such a process over space and time. With the increasing availability of sociospatiotemporal data in recent years, it is now feasible to examine the relationships between physical separation and social interactions at the individual level in a space–time context. This research was intended to offer a spatiotemporal exploratory analysis approach to address this challenge. The first step was to propose the concept of a social closeness space–time path, which is an extension of the space–time path concept in time geography, to represent evolving human relationships in a social closeness space. A space–time geographical information system (GIS) prototype was then designed to support the representation and analysis of space–time paths in both physical and social closeness spaces. Finally, the effectiveness of the proposed concept and design in gaining insight into the impact of physical migration on online social closeness was demonstrated through an empirical study. The contributions of this study include an extension of the time–geographic framework from physical space to social closeness space, the development of a multirepresentation approach in a GIS to integrate an individual’s space–time paths in both physical and social closeness spaces, and an exploratory analysis of the evolving relationships between physical separation and social closeness over time.