The Zhangjiajie Sandstone Peak Forest Geopark in northwest Hunan Province, China, is a comprehensive geopark containing many
spectacular quartz sandstone landforms, limestone karst landscapes and various other important geoheritage resources. It is
listed as a UNESCO World Geopark and is also part of the World Heritage Wulingyuan Scenic and Historic Interest Area for its
important landscape features. Many of the sandstone landforms, particularly the vast number of thin pillars or spires, are
very unusual and serve as the core landscapes of the geopark. But Zhangjiajie displays a diverse range of landform types,
exhibiting spectacular patterns and regular distributions. In this paper, the geomorphic traits, distribution pattern and
constraints of the sandstone landforms of the Zhangjiajie Geopark are examined. Our study indicates that in the outcropping
areas, the sandstones display four distinctive levels from 300 to 1,000 m above sea level, and these extend clearly from the
highest sandstone plateau platform to the center of the valleys. The high sandstone platforms developed close to a flat high-level
erosional surface, and subsequent erosion into this plateau has resulted in successively lower levels of landforms that transition
gradually from peak walls, peak clusters, peak forests and peak pillars to remnant peaks in the lower valley bottoms. The
form and distribution of the Zhangjiajie sandstone landforms are primarily dominated by the geological setting, particularly
the presence of brittle structures (fractures and joint sets) trending NNW, ENE and NE. Triggered by the episodic tectonic
movements, major streams and escarpments frequently occur along these structural directions, while some of the peak walls,
peak clusters and peak forests have their longer elongated axes corresponding to NE or NNW directions, with an increased density
of peak forms at the intersection of these fractures and joints. The geometry of the diverse sandstone landforms is also influenced
to a certain degree by the climatic, water system distribution, lithologic properties, biological process, meteorological
features and denudation processes. The suite of quartz sandstone landforms in Zhangjiajie can be compared with other sandstone
landscapes regionally, and our interpretation of the sandstone peak forest formation processes offers a significant contribution
to the study of topographic features and the geomorphic evolution of sandstone landscapes. 相似文献
Generally, pixels are the basic unit for assessment of landslide susceptibility. However, even if the results facilitate the
comparison, a pixel-based analysis does not clearly illustrate the distribution relationships. To eliminate this deficiency,
the concept of the Landslide Response Unit (LRU) is proposed in this study, for which adjacent pixels that have similar properties
are combined as a basic unit for susceptibility assessment. The Subao River basin, seriously impacted by the Wenchuan Earthquake,
was selected as the study area, and three factors including slope gradient, slope aspect, and slope shape, which have a significant
impact on landslides, were chosen to divide the basin into 25,984 LRUs. Then topographic, geologic, and distance factors were
applied for the landslide susceptibility evaluation. The logistic regression method was used to establish the susceptibility
assessing model by analyzing 2,000 susceptible LRUs and 2,000 un-susceptible LRUs. The model accuracy was defined in terms
of the ROC curve value and the κ value, 0.531 and 0.84, respectively. The susceptibility of landslides was divided into low,
moderate, high, and very high in Subao River basin, and 73% of historical landslides and all four new landslides are in the
highly susceptible zone and very highly susceptible zones. Finally, the LRUs with houses, farmlands, and roads prone to sliding
and burial hazard were assessed separately. On the basis of considering the potential movement directions of the LRUs, the
result found that 1,001 and 835 LRUs probably would be destroyed by slope sliding and landslide burial, respectively. 相似文献
In this paper, the data envelopment analysis (DEA) method is introduced to analyze the input–output efficiency of energy consumption and economic indicators in Beijing city under the influence of short-term climatic factors. Total energy consumption, fixed asset investment, average temperature, precipitation, sunshine hours, average wind velocity and the average pressure being employed as the input variables, gross domestic product (GDP) and per capita disposable income being employed as the output variables, effective technology and the validity of the scale of DEA of 31 decision-making units (DMUs) under the influence of the short-term climatic factors are analyzed, and the inefficient DMUs are improved. Empirical analysis shows that both energy consumption and economic growth are sensitive to short-term climate condition, and the reasonable employing of extreme climatic conditions is a question worthy of consideration. This study provides effective basis for the scientific and reasonable arrangement of Beijing city’s short-term climatic resources and energy–economic development. 相似文献
Storm surge, sea wave, sea ice, red tide and harmful marine creature bloom are main marine disasters occurring in the coast and offshore areas of Qingdao City, Shandong Province, China. Marine disasters mentioned above can be divided into five categories, namely, marine meteorological disasters, marine hydrological disasters, marine geological disasters, marine ecological disasters and man-made marine disasters. Over the past century, the marine disasters in the coast and offshore areas of Qingdao City have caused great economic losses and casualties. In recent years, some problems still exist in emergency management against marine disasters in Qingdao City, such as inaccurate predictions of disasters, untimely early warning and lack of social participation in the emergency management. On the basis of scenario analysis, the authors try to predict different possible scenarios of marine disasters at different early warning levels and propose some optimized emergency countermeasures against marine disaster in Qingdao City. Results of our research can provide a theoretical basis for the revision and improvement of emergency plans and thus guarantee timely and effective emergency management actions against marine disasters in Qingdao City.