Search

Silo-cave is a unique human habitation form on the Loess Plateau in northern China, which consists of an excavated 6–7 m deep pit as the courtyard and cave dwellings in the surrounding four walls. This architecture has had a history of more than 7000 years, and yet such "living fossils for the history of dwellings" are now facing great crises and challenges during rapid social and economic development. In this paper, remote sensing and GIS techniques are used to comprehensively and systematically investigate the spatial distributions and morphological characteristics of silo-caves at both the macro and micro scales. The research shows that silo-cave villages are mainly distributed in economically underdeveloped areas, such as West Henan (Yuxi), South Shanxi (Jinnan), Central Shaanxi (Guanzhong), and East Gansu (Longdong). The morphological evolution patterns of typical silo-cave villages are identified, including: (1) retaining the periphery and rebuilding the inner parts of the villages, (2) retaining the inner parts and expanding the periphery of the villages, and (3) rebuilding the inner parts and expanding the periphery of the villages. These patterns are demonstrated to be influenced by many factors, including landforms, traffic conditions, economic development, population growth, and administrative division adjustment. Sustainable development of these traditional silo-cave villages relies on administrative policy and planning, people's awareness of cultural heritage protection, culture inheritance, industrial transformation, and public services. [ABSTRACT FROM AUTHOR]

Surface greenness reflects the situation of vegetation cover. Vegetation index calculated from the Red and Near Infrared bands of remote sensing images, whose values indicate the level of photosynthetic activity, is monotonically related to surface greenness when vegetation canopy does not fully cover the background soil. Especially for desert regions, vegetation index is positively correlated with vegetation coverage. Therefore, vegetation index can be used to study the change in greenness of desert areas. This study collected MODIS Normalized Difference Vegetation Index (NDVI) data from 2000 to 2010 and analyzed their change over China in this period. The results showed that an increasing trend of NDVI occurred over 66.84% (OLS fitting) or 64.27% (LAD fitting) of China, indicating that China's greenness is increasing overall. Meanwhile, desertification of China decreased. Areas showing large increase in greenness are found in Shaanxi, Shanxi, Ningxia, Henan, Shandong, Qinghai, and Gansu while regions with large decrease in greenness are found in Northeast Inner Mongolia, South Tibet, Jiangsu, and Shanghai. Changes of Qinghai, Gansu, Xinjiang and South Tibet could probably be driven by climate factors. Decrease of greenness in Northeast Inner Mongolia was related to agricultural reclamation. Decrease of greenness in Jiangsu and Shanghai was related to rapid urbanization. Climate factors did not exhibit obvious correspondence to the large increase in greenness in Shaanxi, Shanxi, Ningxia and Gansu, indicating that the changes might have been caused by human factors. The reduction of desert areas in China could probably have been caused by human management and protection at the national scale. [ABSTRACT FROM AUTHOR]