Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM,changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules.This dataset was supported ...Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM,changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules.This dataset was supported by 6843 digital raster images(1:100000 and 1:50000),a countrywide digital vector dataset(1:250000),and historical literature.Comparative data were corrected for seasonal variations using precipitation data.There are presently 2693 natural lakes in China with an area greater than 1.0 km2,excluding reservoirs.These lakes are distributed in 28 provinces,autonomous regions and municipalities and have a total area of 81414.6 km2,accounting for-0.9% of China's total land area.In the past 30 years,the number of newly formed and newly discovered lakes with an area greater than 1.0 km2 is 60 and 131,respectively.Conversely,243 lakes have disappeared in this time period.展开更多
The aerosol number concentration and size distribution were measured with the newly developed Wide-range Particle Spectrometer in summer and winter of 2006 at the urban site of Jinan City. Here reported the characteri...The aerosol number concentration and size distribution were measured with the newly developed Wide-range Particle Spectrometer in summer and winter of 2006 at the urban site of Jinan City. Here reported the characteristics of fine particles of the different observation seasons. Relative high number concentrations for the particles in the diameter range of 10-500 nm were observed in both seasons. It was found that the dominant number distributed in particle diameter smaller than 100 nm and the percentage over the number concentration of all air particles is much higher than what has been measured in other urban sites over the world. The number mean diameter in summer was much smaller than in winter, strongly suggesting the different origin of ultrafine particles in different seasons. That is, particles in ultrafine mode mainly came from nucleation and new particle formation in summer while from traffic emission in winter. The diurnal variation also supported this point. Number concentration in the diameter range of 10-200 um got their peak values at noontime, well correlated with the mixing ratio of SO2 and the intensity of solar radiation in summer. While in winter, those in the same diameter range showed the main peaks during the traffic hours happened in the morning and evening.展开更多
基金supported by the National Special Basic Research Project (Gran No. 2006FY110600)
文摘Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM,changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules.This dataset was supported by 6843 digital raster images(1:100000 and 1:50000),a countrywide digital vector dataset(1:250000),and historical literature.Comparative data were corrected for seasonal variations using precipitation data.There are presently 2693 natural lakes in China with an area greater than 1.0 km2,excluding reservoirs.These lakes are distributed in 28 provinces,autonomous regions and municipalities and have a total area of 81414.6 km2,accounting for-0.9% of China's total land area.In the past 30 years,the number of newly formed and newly discovered lakes with an area greater than 1.0 km2 is 60 and 131,respectively.Conversely,243 lakes have disappeared in this time period.
基金Project supported by the National Basic Research Project(973)of China(No.2005CB422203)the National Post-Doctor Foundation of China(No.20060390990).
文摘The aerosol number concentration and size distribution were measured with the newly developed Wide-range Particle Spectrometer in summer and winter of 2006 at the urban site of Jinan City. Here reported the characteristics of fine particles of the different observation seasons. Relative high number concentrations for the particles in the diameter range of 10-500 nm were observed in both seasons. It was found that the dominant number distributed in particle diameter smaller than 100 nm and the percentage over the number concentration of all air particles is much higher than what has been measured in other urban sites over the world. The number mean diameter in summer was much smaller than in winter, strongly suggesting the different origin of ultrafine particles in different seasons. That is, particles in ultrafine mode mainly came from nucleation and new particle formation in summer while from traffic emission in winter. The diurnal variation also supported this point. Number concentration in the diameter range of 10-200 um got their peak values at noontime, well correlated with the mixing ratio of SO2 and the intensity of solar radiation in summer. While in winter, those in the same diameter range showed the main peaks during the traffic hours happened in the morning and evening.
