Latitudinal patterns and influencing factors of soil humic carbon fractions from tropical to temperate forests

Soil humic carbon is an important component of soil organic carbon (SOC) in terrestrial ecosystems. However, no study to date has investigated its geographical patterns and the main factors that influence it at a large scale, despite the fact that it is critical for exploring the influence of climate change on soil C storage and turnover. We measured levels of SOC, humic acid carbon (HAC), fulvic acid carbon (FAC), humin carbon (HUC), and extractable humus carbon (HEC) in the 0–10 cm soil layer in nine typical forests along the 3800-km North-South Transect of Eastern China (NSTEC) to elucidate the latitudinal patterns of soil humic carbon fractions and their main influencing factors. SOC, HAC, FAC, HUC, and HEC increased with increasing latitude (all P<0.001), and exhibited a general trend of tropical < subtropical < temperate. The ratios of humic C fractions to SOC were 9.48%–12.27% (HAC), 20.68%–29.31% (FAC), and 59.37%–61.38% (HUC). Climate, soil texture, and soil microbes jointly explained more than 90% of the latitudinal variation in SOC, HAC, FAC, HEC, and HUC, and interactive effects were important. These findings elucidate latitudinal patterns of soil humic C fractions in forests at a large scale, and may improve models of soil C turnover and storage.     

中国省域间生态地租分异特征及其影响因素(英文)

Ecological land rent is the excess profit produced by resource scarcity, and is also an important indicator for measuring the social and economic effects of resource scarcity. This paper, by calculating the respective ecological land rents of all the provinces in China for the years 2002 and 2007, and with the assistance of the software programs ArcGIS and GeoDA, analyzes the spatial differentiation characteristics of ecological land rent; then, the influencing factors of ecological land rent differentiation among the provinces are examined using the methods of traditional regression and spatial correlation analysis. The following results were obtained: First, ecological land rent per unit of output in China shows stable distribution characteristics of being low in the southwestern and northeastern provinces, and high in Hebei and Henan provinces. There is also an increasing tendency in the central and western provinces, and a decreasing one in the eastern provinces. In general, the spatial distribution of ecological land rent per unit of output in China is quite scattered. Second, the total ecological land rent shows significant spatial aggregation characteristics, in particular the provinces in China possessing high total amounts of ecological land rent tend to be adjacent to one another, as do those with low total amounts, and the spatial difference characteristics of the eastern, central and western provinces are distinguished. The Bohai Rim, Yangtze River Delta and Pearl River Delta are shown to be highly clustering regions of total ecological land rent, while the western provinces have very low ecological land rent in terms of total amount. Third, population distribution, economic level and industrial structure were all important influencing factors influencing ecological land rent differentiation among provinces in China. Furthermore, population density, urbanization level, economic density, per capita consumption level and GDP per capita were all shown to be positively related to total ecological land rent, which indicates that spatial clustering exists between ecological land rent and these factors. However, there was also a negative correlation between ecological land rent and agricultural output percentage, indicating that spatial scattering exists between ecological land rent and agricultural output percentage.     

城市地籍测量中GPS技术的应用研究

GPS新技术的出现,可以高精度地测定地物点的坐标。特别是应用RTK新技术,依据一定数量的基准控制点,便可以高精度并快速地测定界址点及地物点的坐标。本文尝试利用GPS技术在城市地籍测量方面的应用做一些探讨。     

1962-2014年秦岭主峰太白山地区积雪变化特征及其成因分析

利用太白气象站1962-2014年地面积雪观测资料,太白、眉县气象站1980-2014年高山积雪观测记录和1988-2010年卫星遥感资料,分析了秦岭主峰太白山西部中山区、西部中高山区和中部中高山区积雪初、终日期、积雪日数和积雪深度等的变化特征,以及西部中山区积雪变化的成因.结果表明：1962-2014年太白山西部中山区积雪初日推迟,终日提前,初终间日数减少,积雪日数显著减少,积雪深度呈现波动变浅的趋势;1980-2014年西部中高山区积雪日数同样呈现波动减少趋势,西部中山区和中高山区年积雪日数减少率分别为3.2 d·（10a）^-1和8.9 d·（10a）^-1.1980-2014年中部中高山区积雪初、终日期和积雪日数变化趋势不明显.卫星遥感监测资料分析结果显示太白山地区积雪面积呈现波动减少趋势.1962-2014年西部中山区气温升高,降水减少,积雪参数与气候要素相关分析结果表明气温和累积雪深等参数变化关系密切,气温升高是太白山积雪减少的主要原因.1980-2014年太白山地区7月积雪日数很少,关中八景之一的“太白积雪六月（公历7月）天”已很少见到.     

Analysis of a variational Bayesian adaptive cubature Kalman filter tracking loop for high dynamic conditions

GPS Solutions - Under high dynamic conditions, a robust tracking loop is essential for accuracy positioning with the global position system. In previous studies, the extended Kalman filter...     

面向CORS的精密定位服务中间件平台的设计

目前，卫星定位连续运行参考站网相关技术的应用与研究是测绘界研究的热点之一，国内外各类CORS正相继建立。本文针对CORS服务体系的数据共享和服务共享问题，从软件工程角度对CORS的数据采集、处理、计算、分发、服务等方面作了进一步梳理，建立了较完备的网络体系和软件体系模型，提供了一个较完备的面向CORS的中间件平台设计思路。本文的设计成果和实践，可有效地改善当前CORS领域软件开发现状中软件和研究成果保密、软件功能单一、无统一的开发标准和架构模型等问题，具有一定的实用价值。     

The Relationship between the Aleutian Low and the Australian Summer Monsoon at Interannual Time Scales

The relationship between the boreal winter(December,January,February) Aleutian Low(AL) and the simultaneous Australian summer monsoon(ASM) is explored in this study.A significant correlation is found between the North Pacific index(NPI) and ASM index,the bulk of which is attributed to the significant correlation after late 1970s.Significant differences in precipitation and outgoing long-wave radiation between typical negative and positive NPI years appear over the ASM area.A regression analysis of the circu...     

攀枝花太阳能资源评价

为了有效地开发和利用攀枝花太阳能资源,本文在广泛搜集国内相关地区太阳辐射资料的基础上,整理了攀枝花几十年的太阳能相关气象数据,通过天文辐射量、日照百分率、经纬度、水汽压等因子建立相关辐射量计算模式,系统地分析和研究了攀枝花地区太阳能辐射量的主要分布特征和优势,对大力开发利用攀枝花太阳能资源提供了科学依据,并就如何发展特色农业和旅游业等综合开发利用方面提出了具体可行的对策建议。     

Coupling Relationship Analysis on Households′ Production Behaviors and Their Influencing Factors in Nature Reserves:A Structural Equation Model

A households′production behavior directly influences the quality of the environment and determines the successful development of nature reserves.Meanwhile,the households′production behaviors are complicated by interrelated factors,such as protection attitudes,resource endowment,and family wealth.This research evaluated households near the Crested Ibis National Nature Reserve in Shaanxi Province,acquiring data from 436 households around Yang County and Ningshan County in the south slope of Qinling Mountains,China.Based on the collected data,we developed a structural equation model to evaluate the coupling relationships among households′ protection attitudes,production behaviors,resource endowment,and family wealth.The results showed that:1) households with great resource endowment had more negative attitudes,probably due to their greater protection costs;2) the households with higher education levels had worse protection attitudes;3) the households with more family wealth were likely to use fewer fertilizers,pesticides,and firewood;4) the households with more resource endowment showed less production and management behaviors;5) the enhancement of households’ attitudes improved production behaviors to protection the environment,but the effects were not statistically significant.Our results provide a basis for the government’s protection policy making,exploring the effective management measures that are beneficial for both nature reserve management and community development.