Soil respiration mapped by exclusively use of MODIS data for forest landscapes of Saskatchewan,Canada

Soil respiration (R_s) is of great importance to the global carbon balance. Remote sensing of R_s is challenging because of (1) the lack of long-term R_s data for model development and (2) limited knowledge of using satellite-based products to estimate R_s. Using 8-years (2002–2009) of continuous R_s measurements with nonsteady-state automated chamber systems at a Canadian boreal black spruce stand (SK-OBS), we found that R_s was strongly correlated with the product of the normalized difference vegetation index (NDVI) and the nighttime land surface temperature (LSTn) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) imagery. The coefficients of the linear regression equation of this correlation between R_s and NDVI × LSTn could be further calibrated using the MODIS leaf area index (LAI) product, resulting in an algorithm that is driven solely by remote sensing observations. Modeled R_s closely tracked the seasonal patterns of measured R_s and explained 74–92% of the variance in R_s with a root mean square error (RMSE) less than 1.0 g C/m²/d. Further validation of the model from SK-OBS site at another two independent sites (SK-OA and SK-OJP, old aspen and old jack pine, respectively) showed that the algorithm can produce good estimates of R_s with an overall R² of 0.78 (p < 0.001) for data of these two sites. Consequently, we mapped R_s of forest landscapes of Saskatchewan using entirely MODIS observations for 2003 and spatial and temporal patterns of R_s were well modeled. These results point to a strong relationship between the soil respiratory process and canopy photosynthesis as indicated from the greenness index (i.e., NDVI), thereby implying the potential of remote sensing data for detecting variations in R_s. A combination of both biological and environmental variables estimated from remote sensing in this analysis may be valuable in future investigations of spatial and temporal characteristics of R_s.     

大都市郊区农村土地制度综合改革的探索与创新——以上海市浦东新区为例

在中央提出推进新型城镇化和实施农村土地制度改革试点的新形势下,如何适应客观实际、率先探索出大都市郊区土地综合改革新路并为全国其他地区改革提供参考借鉴,具有十分重要的现实意义。本文以上海市浦东新区为例,深入分析梳理大都市郊区农村土地开发利用和改革创新所面临的问题与主要瓶颈,在此基础上就如何深化农村土地制度综合改革的总体思路和具体措施提出有针对性和可操作性的对策建议。     

农村土地确权勘测定界中界址点测量方法探讨

界址点测量是土地确权勘测定界的重要工作之一。文中介绍了界址点的不同测量方法,主要包括全站仪坐标测量法、常规GPS-RTK测量法、单基站CORS测量法和网络CORS测量法,并以实例分析了这四种不同测量方法的精度,得出了有益的结论。     

抵偿高程面任意带高斯投影坐标系统的变形分析及应用

对投影变形问题进行了分析,结合实例,探讨了抵偿高程面任意带高斯投影对控制投影变形的实用性。     

基于Flex的跨平台移动土地信息管理系统设计与实现

将具有跨平台性的Flex移动开发技术与ArcGIS Server ,ArcGIS Flex API等GIS相关技术结合,构建了跨平台移动GIS并应用于山西省襄汾县土地信息管理工作中,在多平台的移动智能终端上实现了土地信息数据查询、地块信息实时更新、移动GPS定位等功能。提高了国土资源管理信息化程度,提高了工作效率和业务管理水平,为移动GIS在土地管理中的应用与研究上提供补充和参考。     

基于移动GIS的土地集约利用信息采集终端系统

为了解决土地利用的种类复杂、分界不清、分界点精度要求高等问题,研制集GPS,Mobile GIS,PDA,网络通信等先进技术为一体的,能够快速获取土地利用信息的土地集约利用信息采集终端系统,为城市土地集约化利用信息及时、准确的获取提供技术保障。     

快速城市化地区建设用地演变驱动力研究——以深圳市龙岗区为例

在综述国内LUCC驱动力研究的基础上,确定了驱动因子。以深圳市龙岗区为例,基于非线性的Lo-gistic模型,分析研究了建设用地演变的驱动力。     

Advances in understanding of the mechanism for generation of earthquake thermal precursors detected by satellites

Stresses building up during an earthquake preparation phase also manifest themselves in the form of a so called increased land surface temperature (LST) leading to a thermal precursor prior to the earthquake event. This phenomenon has now been validated by our observations of short-term thermal anomalies detected by infrared satellite sensors for several recent past earthquakes around the world. The rise in infrared radiance temperature was seen to vary between 5 and 12 °C for different earthquakes. We discuss in this paper different explanations for the generation of such anomalies that have been offered. Emission of gases due to the opening and closure of micropores upon induced stresses and also the participation of ground water have been propounded as a possible cause for generation of thermal anomalies. Seismo-ionosphere coupling, by which gases like radon move to the earth–atmosphere interface and cause air ionization thus bringing about a change in air temperature, relative humidity, etc., has been put forth by some workers. A mechanism of low frequency electromagnetic emission was tested and experimented by scientists with rock masses in stressed conditions as those that exist at tectonic locations. The workers proposed the positive hole pair theory, which received support from several scientific groups. Positive holes (sites of electron deficiency) are activated in stressed rocks from pre-existing yet dormant positive hole pairs (PHPs) and their recombination at rock–air interface leads to a LST rise. A combination of remote sensing detection of rock mechanics behavior with a perception of chemistry and geophysics has been applied to propose the remote sensing rock mechanics theory. Remote sensing detections of such anomalies confirm so far proposed lab theories for such a hotly debated field as earthquake precursor study by providing unbiased observations with consistency in time and space distribution.     

The Creation of a National Agricultural Land Use Dataset: Combining Pycnophylactic Interpolation with Dasymetric Mapping Techniques

Agricultural Census data is summarised over spatially coarse reporting units for reasons of farm confidentiality. This is problematic for research at a local level. This article describes an approach combining dasymetric and volume preserving techniques to create a national land use dataset at 1 km² resolution. The results for an English county are compared with contemporaneous aggregated habitat data. The results show that the accurate estimates of local agricultural land use (Arable and Grass) patterns can be estimated when individual 1 km squares are combined into blocks of > 9 squares, thereby providing local estimates of agricultural land use. This in turn allows more detailed modelling of land uses related to specific livestock and cropping activities. The dataset created by this work has been subject to extensive external validation through its incorporation into a number of other national models: nitrate leaching (e.g. MAGPIE, NEAP‐N), waste, and pathogen modelling related to agricultural activity.     

利用新技术进行土地利用更新调查的几点体会

通过作者使用新技术进行安阳市土地利用更新调查的体会,指出了新技术存在的优势及新老技术结合的方法,并对更新调查的基本要求与程序作了比较详细的说明,最后指出利用MapGIS等地理信息软件进行二次开发从而实现土地利用现状图、文、表一体化的工作方式和变更、管理的一体化将成为土地利用调查及管理的主要方向.