1 INTRODUCTION The Jiangnan Region is in the eastern part of China that is south of the Changjiang River and north of Nanling Mountains. It encompasses southern Hunan, southern Jiangxi, most of Fujian and southern Zhejiang. It is a base for the production of grain and cotton among other well-developed agricultural economy. Its eastern coastal area is also an important industrial base. Climatic anomalies in the region are threats to human life and property for tens of millions peopl… 相似文献
The chemical characteristics and phytoplankton biomass (measured as chlorophyll-a concentrations) of seven lakes and one reservoir in the Ethiopian rift-valley were studied during the wet and dry seasons between 1990 and 2000. Mean concentrations of three major plant nutrients (nitrate-nitrogen, soluble reactive phosphorus, and silicate) increased during the wet seasons in four of the seven lakes, presumably as a result of mixing events and input from runoff. The changes in the major nutrient concentrations in the rest of the lakes were variable, but concentrations were usually higher during the dry seasons, most likely as a response to temporal variation in the phytoplankton biomass. pH measurements of the lakes did not show marked differences between the wet and dry seasons. Salinity (measured as conductivity) and total ions seemed to increase during the wet seasons in some of the lakes, possibly as a result of inflows that might carry high concentrations of solutes due to the heavy rains. Chlorophyll-a concentrations were higher during the dry seasons in most lakes except in three relatively more productive lakes. The results suggest that there could be light limitation in some of the Ethiopian rift-valley lakes, and events associated with the wet and dry seasons could bring about contrasting changes in nutrient levels and phytoplankton biomass in lakes, depending on the physical characteristics of the lakes. 相似文献
Urban agglomerations in China have become the strategic core of national economic development and the main component of the new type of urbanization. However, they are threatened by a series of eco-environmental problems and challenges, including the severe overexploitation of natural resources. Eco-efficiency, which is defined as accomplishing the greatest possible economic benefit with the least possible resource input and damage to the environment, is used as an indicator to quantify the sustainability of urban agglomerations. In this work, a traditional data envelopment analysis (DEA) model with a slack-based measurement (SBM) model of undesirable outputs, was used to assess and compare the economic efficiency and eco-efficiency of four major urban agglomerations in eastern China (UAECs) in 2005, 2011, and 2014. The spatio-temporal characteristics of the evolution of urban agglomerations were analyzed. Based on the results of a slack analysis, suggestions for improving the eco-efficiency of the four UAECs are provided. The overall economic efficiency of urban agglomerations located in the Shandong Peninsula, Yangtze River Delta, and Pearl River Delta displayed a V-shaped pattern (decreased and then increased). In contrast, the overall economic efficiency of the Beijing-Tianjin-Hebei urban agglomeration declined during the study period. The Beijing-Tianjin-Hebei urban agglomeration had a considerable loss of economic efficiency due to pollution, whereas the Shandong Peninsula urban agglomeration was less impacted. Overall, the eco-environmental efficiency of the four UAECs declined from 2005 to 2011 and then increased from 2011 to 2014. In addition, the urban eco-efficiency in the four coastal UAECs was characterized by different evolution patterns. The eco-efficiency was higher in the peri-urban areas of the core cities, riverside areas, and seaside areas and lower in the inland cities. The core cities of the Beijing-Tianjin-Hebei, Yangtze River Delta, and Pearl River Delta urban agglomerations were characterized by high resource consumption, economic benefit output, and eco-efficiency. In most of cities in the urban agglomerations, the emission of pollutants declined, leading to a reduction of pollutants and mitigation of environmental problems. In addition, a differential analysis, from the perspective of urban agglomeration, was performed, and concrete suggestions for improvement are proposed.
We selected the 103 M_L≥2. 5 earthquake waveform data from the Inner Mongolia-Ningxia border during 2009-2015,which was recorded by the Inner Mongolia Digital Seismic Networks and used the simplex method, Hyposat method, double difference location method,and deterministic method (PTD) for the determination of focal depth,and compared the results. The CAP moment tensor inversion method is used to determine the focal depths of the Alxa Left Banner M5. 8 and M4. 2 earthquakes. The final results of the focal depth by the deterministic method (PTD) and the double difference location method fit well with the tectonic characteristics of the Inner Mongolia-Ningxia border area,but those of the simplex method and the Hyposat method do not. The average depth of the Inner Mongolia-Ningxia border seismic tectonic zone is 13. 32 ± 8 km. 相似文献
