宁波市洪涝灾害的历史与区域分析

本文提出了地区洪涝灾害的历史规律和区域差异分析的一般方法和模式，通过对典型地区（宁波市）洪涝资料的统计分析，探讨了区域洪涝的时段性，周期性，以及与旱灾和人口的关系，文章首次提出了洪涝指数的概念，并以计算洪涝指数的方法表达洪涝灾情区域差异分析的结果。     

西北地区降水对陆面特征敏感性的数值试验

本文是一个用大气环境模式研究中国西北地区陆面特征改变之后影响其降水的数值试验，模式中假定西北地区的植被完全被裸陆代替，对６、７、８月进行数值积分，以便检查夏季大气环流对陆面特征的响应，数值试验的结论是：陆面反照率升高后，与之相伴随的是降水率下降，并且大气的下沉运动控制了该地区。     

Exploring the relationship between density and completeness of urban building data in OpenStreetMap for quality estimation

OpenStreetMap (OSM) is a free spatial data source based on crowd sourced data. Although the OSM data have a range of applications, such as generating 3D models, and routing and navigation, quality issues are still significant concerns when using the data. Several studies have undertaken quality assessments by comparing OSM data with reference data. However, reference data are not always available due to high costs or licensing restrictions, and very few studies have quantitatively estimated the quality of OSM data under conditions where the corresponding reference data are not available. This study proposed the use of a building density (or building coverage ratio) indicator as a proxy, and designed a series of experiments involving different study areas to quantitatively explore the relationship between building density and building completeness for OSM data in urban areas. The residuals (estimated building completeness and reference building completeness) were also analyzed. Two main results were found from the experiments. (1) There was an approximate linear relationship between building density and building completeness in the OSM data. More precisely, the building completeness of OSM data was approximately 3.4–4 times the building density of OSM data. (2) Approximately 70–80% of the absolute residuals were smaller than 10%, and 80–90% of them were smaller than 20%. This shows that, in most cases, estimated building completeness was close to the corresponding reference building completeness. Therefore, we concluded that the building density indicator is a potential proxy for the quantitative completeness estimation of OSM building data in urban areas. The limitations of using this indicator were also addressed.     

河南省老龄人口的空间分布及变动

根据人口普查数据资料,运用数理统计分析方法对河南省老龄人口的分布及其变动、人口密度及其变化趋势等进行分析。河南乡村老龄人口仍占多数,但其分布重心正逐步向城镇转移;各地区老龄人口规模相差较大且分异明显,同时,地区间老龄人口密度差异悬殊,增长变化差距很大;老龄人口分布虽存在地区差异,但发展变化总的趋势是人口老龄化、高龄化加速发展,养老服务需求增大。建立科学合理的社会养老服务体系是当前应对人口老龄化、保障和改善民生的必然要求。     

Capacity of soil loss control in the Loess Plateau based on soil erosion control degree

The capacity of soil and water conservation measures, defined as the maximum quantity of suitable soil and water conservation measures contained in a region, were determined for the Loess Plateau based on zones suitable for establishing terraced fields, forestland and grassland with the support of geographic information system (GIS) software. The minimum possible soil erosion modulus and actual soil erosion modulus in 2010 were calculated using the revised universal soil loss equation (RUSLE), and the ratio of the minimum possible soil erosion modulus under the capacity of soil and water conservation measures to the actual soil erosion modulus was defined as the soil erosion control degree. The control potential of soil erosion and water loss in the Loess Plateau was studied using this concept. Results showed that the actual soil erosion modulus was 3355 t?km^-2?a^-1, the minimum possible soil erosion modulus was 1921 t?km^-2?a^-1, and the soil erosion control degree was 0.57 (medium level) in the Loess Plateau in 2010. In terms of zoning, the control degree was relatively high in the river valley-plain area, soil-rocky mountainous area, and windy-sandy area, but relatively low in the soil-rocky hilly-forested area, hilly-gully area and plateau-gully area. The rate of erosion areas with a soil erosion modulus of less than 1000 t?km^-2?a^-1 increased from 50.48% to 57.71%, forest and grass coverage rose from 56.74% to 69.15%, rate of terraced fields increased from 4.36% to 19.03%, and per capita grain available rose from 418 kg?a^-1 to 459 kg?a^-1 under the capacity of soil and water conservation measures compared with actual conditions. These research results are of some guiding significance for soil and water loss control in the Loess Plateau.     

面向问题的空间应用表达与实现

讨论空间应用的一种面向问题的表达方法与实现机制。为解决空间应用的描述问题,在建立时空一体化空间数据模型基础上,定义了对SQL进行扩展的时空复合查询语言,实现了对空间应用问题的非过程化描述;研究复杂空间应用的表达问题,讨论时空复合查询语言的限制,并在语言中引入流机制,通过空间应用问题的组合实现更为复杂的空间应用,并支持空间数据分布式计算;最后给出若干空间应用实例及其面向问题的表达。     

汾河流域城乡聚落体系发展潜能测度及空间模式探究

以11 188个自然聚落斑块为研究对象,基于场强模型,定量测度汾河流域城乡聚落体系发展潜能,借助GIS技术和地理探测器模型,分析其空间格局特征及驱动因素,进而探讨流域城乡融合发展空间模式。结果表明:①城乡聚落斑块发展潜能差异显著,且空间分布极不均衡;纵向上中游流域高于下游流域高于上游流域,横向上河谷盆地区高于周边缓丘区高于两侧山丘区。②聚落斑块发展潜能具有正向空间自相关性,高值斑块聚类显著;具有空间异质性特征且方向性明显,汾河主河道方向联动效应最强,空间联系最紧密;存在局域热点区,并呈现"主核–廊道–次核"的空间结构形态。③自然基础、社会经济发展水平和区位条件共同影响着城乡聚落体系发展潜质及空间结构形态;融合发展采取非均衡增长路径,市、县、镇、村全局考虑,构建"强化核心点–培育发展轴–扶持特色区–带动全流域"的逐层推进式空间发展模式。     

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.     

Evolution and driving forces of rural functions in urban agglomeration: A case study of the Chang-Zhu-Tan region

Journal of Geographical Sciences - As the Rural Revitalization Strategy is gradually implemented, China’s rural areas are set to have more diverse function requirements. This paper selects...     

气候和人为因素对植被变化影响的评价方法综述

系统评价气候变化和人为因素引起的植被退化,对有效开展生态工程建设、实现生态环境的可持续发展具有重要意义。目前绝大多研究主要分析气候因素对植被变化的影响,分析气候因素和人类活动对植被变化的双重影响少有研究。本文主要介绍这一双重影响对植被变化的贡献程度的主要研究方法——定性-半定量法、回归分析法、残差趋势法、基于净第一生产力的评价方法。综述分析了气候和人为因素对植被变化驱动的主要结论,总结目前各研究方法存在的问题,提出了未来需要重点加强气候和人为因素对植被变化驱动因素的分解研究,加强模型评价和不确定性量化研究等。