Coordinated development of land multi-function space: An analytical framework for matching the supply of resources and environment with the use of land space for ecological protection,agricultural production and urban construction

Journal of Geographical Sciences - Based on the carrying capacity of the resources and the environment, this article defines the connotation of the land multifunctional space (LMFS) from three...     

结合GPS和GLAS数据生成Dome-A区域DEM

详细阐述了利用GLAS数据和GPS数据生成Dome-A地区DEM的方法。首先进行GLAS数据转化,便于与GPS数据结合,提出一种快速搜索GLAS和其光斑(Footprint)覆盖GPS点的算法,比较GLAS数据和GPS数据发现,均值差异最大为1.118m,最小为0.997m,而标准差稳定为5—6cm,在进行椭球变换修正之后,差值最大为0.405m,最小为0.284m;之后利用改进的角度限差法沿测线对GPS数据进行特征点提取,得到抽稀之后的数据;再利用抽稀之后的GPS数据和处理后的GLAS数据使用克里金插值方法生成研究区DEM。利用1199个GPS点和53个GLAS检验点对最后生成的DEM进行了精度分析,残差中误差为5cm,最大残差绝对值为12cm。利用原始GPS数据,原始GPS数据和GLAS数据,处理后GPS数据利用克立金插值方法分别生成了研究区的DEM,通过等高线提取分析以及检验点的误差分析,处理后的GPS数据生成的DEM要优于原始GPS数据的,证明GPS处理的必要性。     

Fast algorithm for maneuvering target detection in SAR imagery based on gridding and fusion of texture features

Designing detection algorithms with high efficiency for Synthetic Aperture Radar (SAR) imagery is essential for the operator SAR Automatic Target Recognition (ATR) system. This work abandons the detection strategy of visiting every pixel in SAR imagery as done in many traditional detection algorithms, and introduces the gridding and fusion idea of different texture features to realize fast target detection. It first grids the original SAR imagery, yielding a set of grids to be classified into clutter grids and target grids, and then calculates the texture features in each grid. By fusing the calculation results, the target grids containing potential maneuvering targets are determined. The dual threshold segmentation technique is imposed on target grids to obtain the regions of interest. The fused texture features, including local statistics features and Gray-Level Co-occurrence Matrix (GLCM), are investigated. The efficiency and superiority of our proposed algorithm were tested and verified by comparing with existing fast detection algorithms using real SAR data. The results obtained from the experiments indicate the promising practical application value of our study.     

Gravity observations along the eastern margin of the Tibetan Plateau and an application to the Lushan M S7.0 earthquake

This paper introduces relative and absolute gravity change observations in the eastern portion of the Tibetan Plateau. We analyze and discuss a change that occurred in 2010 in the gravity along the eastern margin of the plateau and the relationship between this change and the 2013 Lushan M _S7.0 earthquake. Our results show that: (1) before the Lushan M _S7.0 earthquake, gravity anomalies along the eastern margin of the Tibetan Plateau changed drastically. The Lushan earthquake occurred at the bend of the high gradient zone of gravity variation along the southern edge of the Longmenshan fault zone. (2) The 2013 Lushan earthquake occurred less than 100 km away from the epicenter of the 2008 Wenchuan earthquake. Lushan and Wenchuan are located at the center of a four-quadrant section with different gravity anomalies, which may suggest that restoration after the Wenchuan earthquake may have played a role in causing the Lushan earthquake. (3) A medium-term prediction based on changes in gravity anomalies was made before the Lushan M _S7.0 earthquake, in particular, a prediction of epicenter location.     

An improved Landsat Image Mosaic of Antarctica

A revised Landsat Image Mosaic of Antarctica (LIMA) is presented, using the 1073 multi-band scenes of the original Landsat-7 ETM+ LIMA image collection available at the United States Geological Survey (USGS: http://lima.usgs.gov/). Three improvements have been applied during the data processing: (1) DN saturation is adjusted by adopting a linear regression, which has a lower root mean square error than the ratio regression used by LIMA; (2) solar elevation angle is calculated using pixel-level latitude/longitude and the acquisition time and date of the central pixel of the scene, improving slightly upon the bilinear interpolation of the solar elevation angles of scene corners applied in LIMA; and (3) two additional image bands, Band 5 and Band 7, are sharpened using the panchromatic band (Band 8) and a Gram-Schmidt Spectral Sharpening algorithm to more easily distinguish snow, cloud and exposed rocks. The final planetary reflectance product is stored in 16-bit bands to preserve the full radiometric content of the scenes. A comparative statistical analysis among 12 sample regions indicates that the new mosaic has enhanced visual qualities, information entropy, and information content for land cover classification relative to LIMA.     

基于ISM的城市脆弱性影响因素研究——以日本城市地震救援恢复为例

城市脆弱性受自然环境、经济条件与社会环境等诸多因素影响,且城市脆弱性影响因素之间关系错综复杂.在前人研究基础上,从自然、经济和社会3个维度选取25项影响因素,采用解释结构模型对上述因素进行详细阐述,揭示了影响城市脆弱性的直接因素、间接因素与根本因素的层次脉络:城市结构与功能布局、社会与经济现状直接决定城市灾变敏感性、应对能力与恢复能力高低;在操作层面优化城市的各项功能,实施完善而具体的防灾减灾措施,能间接提高城市应对灾变的防御恢复能力;城市经济总量决定区域范围内脆弱性的总体水平,经济基础是影响城市系统脆弱性的根本因素.最后以日本3.11地震灾害救援恢复为例进行了实证分析.     

Quantifying the effects of climate change and human activities on runoff in the water source area of Beijing,China

Abstract

Quantitative assessment of the effects of climate change and human activities on runoff is very important for regional sustainable water resources adaptive management. In this study, the non-parametric Mann-Kendall test is used to identify the trends in and change points of the annual runoff with the aim of analysing the changing characteristics of the hydrological cycle. The study presents the analytical derivation of a method which combines six Budyko hypothesis-based water–energy balance equations with the Penman-Monteith equation to separate the effects of climate change and human activities. The method takes several climate variables into consideration. Results based on data from the Yongding River basin, China, show that climate change is estimated to account for 10.5–12.6% of the reduction in annual runoff and human activities contribute to 87.4–89.5% of the runoff decline. The results indicate that human activities are the main driving factors for the reduction in runoff.

Editor Z.W. Kundzewicz; Associate editor C.Y. Xu     

Estimating influences of urbanizations on meteorology and air quality of a Central Business District in Shanghai, China

Two sensitivity simulations were performed and compared by model in order to understand how high-rise buildings influence meteorology and air quality in the Lujiazui Central Business District (CBD) of Shanghai, China. The coupled meteorological-photochemical model, Metphomod, was used, with a 500-m horizontal resolution and the observations and the simulated results generally agreed well. The scheme considering buildings within roughness could reduce uncertainties in the simulated meteorological conditions and concentrations of air pollutants. The high-rise buildings decreased wind speeds by 0.5–4 m/s, increased temperatures by up to 1 °C and turbulent kinetic energy by 1–2 J/m³ in the Lujiazui CBD. The changes in meteorological conditions also increased NO by about 2–5 %. However, the complex meteorological changes of higher temperatures and stronger turbulent kinetic energy, coupled with changes of precursors’ concentrations in the Lujiazui CBD, decreased O₃ concentrations by up to 6 % somewhere, while increasing O₃ formation by up to 2 % in downwind areas. The results suggested that it was necessary to include high-rise building parameters in models when estimating the meteorology and diagnosing air pollution of highly urbanized regions.     

Near-real-time one-kilometre Soil Moisture Active Passive soil moisture data product

The coarse resolution soil moisture (SM) data from NASA SMAP mission have been steadily produced with the expected performance since April 2015. These coarse resolution observations could be downscaled to fine resolution using fine scale observations of SM sensitive quantities from existing satellite sensors. For operational users who need near-real-time (NRT) high resolution SM data, the downscaling approach should be feasible for operational implementation, requiring limited ancillary information and primarily depending on readily available satellite observations. Based on these principles, nine potential candidate downscaling schemes were selected for developing an optimal downscaling strategy. Using remotely sensed land surface temperature (LST) and enhanced vegetation index (EVI) observations, the optimal downscaling approach was tested for operational producing a NRT 1 km SM data product from SMAP. Comprehensive assessments on the 1 km SM product were conducted based on agreement statistics with in-situ SM measurements. Statistical results show that the accuracy of the original coarse spatial resolution SMAP SM product can be significantly improved by 8% by the downscaled 1 km SM. With respect to the in-situ measurements, the 1 km SM mapping capability developed here presents a clear advantage over the SMAP/Sentinel SM data product; and it also provides better data availability for users. This study suggests that a NRT 1 km SMAP SM data product could be routinely generated from SMAP at the centre for Satellite Applications and Research of NOAA NESDIS for operational users.     

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