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快速有效地评估城市化过程带来的生态环境后果,对于优化城市土地利用格局、降低和防范城市生态环境风险,非常必要。因此本文综合利用DMSP/OLS夜间灯光数据和SPOT/VGT时间序列数据等多源遥感信息,以NDVI与时间的积分值来表征一定时间段内的植被初级生产力,探讨了环渤海城市群地区城市化过程对植被初级生产力的季节性变化影响。发现:(1)研究区全年总的平均初级生产力总体表现为城市地区低于非城市地区的特征。(2)研究区平均初级生产力一般是在8月份最高,而在1月份最低;同时,一个生长季内,平均初级生产力总体呈现为4-11月城市地区低于非城市地区,而12月到次年3月则是城市地区要高于非城市地区的趋势,但这种趋势在各土地覆盖类型间也存在很大的不同。(3)研究区全年总的平均初级生产力,城市地区NDVI为110.23d/km^2,而非城市地区为123.94d/km^2,两者相差13.71d/km^2,即城市化过程已经在一定程度上减弱了研究区的植被初级生产力。
In the paper,the change of vegetations' primary productivity was used as a central evaluating factor,the Defense Meteorological Satellite Program /Operational Linescan System(DMSP/OLS) data and multisource satellite and geospatial data were combined in a geographic information system,and the Normalized Difference Vegetation Index(NDVI) was used to quasi-quantificationally study the effect of urbanization on the photosynthetic productivity and its seasonal changing law in the urban agglomerations of Bohai Rim,from the view of land use change.This work is an important preparation to further study the ecological effects of urbanization in all country scope.The conclusions are as followings:(1) The yearly mean total productivity of the urban portion is less than that of non-urban part.(2)The yearly total average productivity commonly in August rises to its tiptops,and in January touches down its nadirs.Moreover,in one growing season,the tendency of the productivity of the urbanized portion is less than that of non-urban part from April to November,but from December to March of next year that is precise antithesis.In the meantime,the tendency also has some differences to every land cover class.(3) In a global scale view,the yearly total average productivity for urban and non-urban areas of all the study area including all the land cover types is 110.23d/km~2 and 123.94d/km~2, respectmely which has a dispersion of 13.71d/km~2.It indicates that the continuing process of urbanization has been weakening the primary productivity of the Bohai Rim.