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| 1 | The spatial-temporal pattern and influencing factors of negative air ions in urban forests, Shanghai, China显示文摘Negative air ions are natural components of the air we breathe. Forests are the main continuous natural source of negative air ions(NAI). The spatio-temporal patterns of negative air ions were explored in Shanghai, based on monthly monitoring in 15 parks from March 2009 to February 2010. In each park, sampling sites were selected in forests and open spaces. The annual variation in negative air ion concentrations(NAIC) showed peak values from June to October and minimum values from December to January. NAIC were highest in summer and autumn, intermediate in spring, and lowest in winter. During spring and summer, NAIC in open spaces were significantly higher in rural areas than those in suburban areas. However, there were no significant differences in NAIC at forest sites among seasons. For open spaces, total suspended particles(TSP) were the dominant determining factor of NAIC in summer, and air temperature and air humidity were the dominant determining factors of NAIC in spring, which were tightly correlated with Shanghai's ongoing urbanization and its impacts on the environment. It is suggested that urbanization could induce variation in NAIC along the urban-rural gradient, but that may not change the temporal variation pattern. Furthermore, the effects of urbanization on NAIC were limited in non-vegetated or less-vegetated sites, such as open spaces, but not in well-vegetated areas, such as urban forests. Therefore, we suggest that urban greening, especially urban forest, has significant resistance to theeffect of urbanization on NAIC. | Hong Liang Xiaoshuang Chen Junguang Yin Liangjun Da | 2014 | Journal of Forestry Research2014，25，4： | 19 |
| 2 | Temporal variations of surface water quality in urban, suburban and rural areas during rapid urbanization in Shanghai, China显示文摘 | Junying Wang Liangjun Da Kun Song Bai-Lian Li | 2007 | Environmental Pollution2007，，2： | 1 |
| 3 | Temporal variations of surface water quality in urban,suburban and rural areas during rapid urbanization in Shanghai China显示文摘 | Junying Wang Liangjun Da Kun Song | | 0，，02： | 1 |
| 4 | Vegetation classification of East China with multi-temporal NOAA-AVHRR data显示文摘East China lies in the subtropical monsoon cli-matic zone and is dominated by subtropical evergreen broad-leaved forests,a unique vegetation type mainly dis-tributed in East Asia with the largest distribution in China.It is important to be able to monitor and estimate forest biomass and production,regional carbon storage,and global climate change impacts on these important vegetation types.In this paper,we used coarse resolution remote sensing data to identify the vegetation types in East China and developed a map of the spatial distribution of vegetation types in this region.Nineteen maximum normalized difference vegeta-tion index(NDVI)composite images(acquisition time span of 7 months from February to August),which were derived from 10 days National Oceanographic and Atmospheric Administration(NOAA)Advanced Very High Resolution Radiometer(AVHRR)channel 1 and channel 2 observa-tions,an unsupervised classification method,and the ISODATA algorithm were employed to identify the vegeta-tion types.To reduce the dimensions of the dataset resulted in a total of 28 spectral clusters of land-cover of which two clusters were urban/bare soil and water,the images were processed using principal component analysis(PCA).The 26 remaining spectral clusters were merged into six vegeta-tion types using the Chinese vegetation taxonomy system:evergreen broad-leaved forest,coniferous forest,bamboo forest,shrub-grass,aquatic vegetation,and agricultural vegetation.The spatial distribution and areal extent for the coniferous forests,shrub-grass,evergreen broad-leaved for-ests,and agricultural vegetation were calculated and com-pared with the Vegetation Atlas of China at a 1:1,000,000 scale.The spatial accuracy and the area accuracy for conif-erous forests,shrub-grass,evergreen broad-leaved forests,and agricultural vegetation were 79.2%,91.3%,68.2%and 95.9%and 92.1%,95.9%,63.8%and 90.5%,respectively.The spatial accuracy and area accuracy of the bamboo forest were 28.7%and 96.5%,respectively;the spatial accuracy of aquatic vegetation was 69.6%,but there was a significant difference in its area accuracy because image acquisition did not cover the full year.Our study demonstrated the fea-sibility of using NOAA-AVHRR to identify the different vegetation types in the subtropical evergreen broad-leaved forest zone in East China.The spatial location of the six identified vegetation types agreed with the actual geo-graphical distribution of the vegetation types in East China. | LI Junxiang DA Liangjun WANG Yujie SONG Yongchang | 2006 | Frontiers in Biology2006，1，3： | 0 |
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