In-situ measurement of atmospheric CO_2 was made at the top of the Waliguan Mountain(36°17′N,100°54′E,3816 m asl).where the air is not directly affected by the local anthropogenic and natural sources,by us...In-situ measurement of atmospheric CO_2 was made at the top of the Waliguan Mountain(36°17′N,100°54′E,3816 m asl).where the air is not directly affected by the local anthropogenic and natural sources,by using a nondispersive infrared(NDIR)analyzer and following the procedures proposed by WMO.The CO_2 in the flask samples collected on the mountain was also analyzed in a laboratory.The measurements uncover the daily,monthly and seasonal variabilities and the baseline level of the CO_2 in the air over the“clean”area of Chinese hinterland.Results suggest that the CO_2 concentration over the East Asia continent has evident periodical variation,similar to that of global distribution.In 1992,an annual mean baseline CO_2 concentration of 356.4 ppm over the continent was obtained.The annual mean val- ue was 357.2 ppm for 1993.Some relationships between the CO_2 concentration at Waliguan and the weather conditions, especially,wind speed and direction are found through the observation.展开更多
The comprehensive impact of atmospheric dry deposition and wet deposition and the pollution sources of farmlands, mining areas, and towns along the Baihe River on the water quality of Miyun reservoir is investigated f...The comprehensive impact of atmospheric dry deposition and wet deposition and the pollution sources of farmlands, mining areas, and towns along the Baihe River on the water quality of Miyun reservoir is investigated from the angle of the complex sources of air-soil-water pollution processes, in the context of the 1990-2001 precipitation chemical data at Shangdianzi station-a WMO regional background air pollution monitoring station 15 km far from the Miyun reservoir, in conjunction with the atmospheric dry deposition and wet deposition data of the 2002 -2003 Beijing City Air Pollution Observation Field Experiment (BECAPEX). Analysis results suggest that the major ions in precipitation in the Miyun reservoir region in this period were SO 42-, NO 3-, NH4+ and Ca2+; wet acid deposition quantity of Miyun reservoir in the summer half year (April to September) was greater than the quantity in the winter half year (October to March), and the annual wet acid deposition in the reservoir exhibited a rising trend with the mean 1038.45 t, the maximum 1766.31 t occurred in 1996, and the minimum 604.02 t in 1994; the long-term averaged pH of atmospheric precipitation in the Miyun reservoir region was 5.20, i.e. weakly acidic, and the interannual variation of pH values displayed a falling trend. pH values of water body at various depths in the Miyun reservoir were all greater than 7.0, but they exhibited vertical and horizontal nonhomogeneity, and at the same region pH decreased vertically with depth; the 2002 and 2003 annual dustfalls in the Miyun reservoir were 13513.08 t and 3577.64 t, respectively, and the spring dustfall was the number one in a year, accounting for the 61.91% and 44.56% of the annual totals of 2002 and 2003, respectively. Because the atmospheric dry deposition and wet depositions contain multiple types heavy metal elements and harmful elements, they to some extent exacerbated the eutrophication, acidification and potential heavy metal pollution of the reservoir water. The above comprehensive analysis result展开更多
This paper presents a general-purpose analysis package able to solve two- and three- dimensional analysis problems. The system can use the following methods of solution: Successive Approximation (SA), Optimal Interpol...This paper presents a general-purpose analysis package able to solve two- and three- dimensional analysis problems. The system can use the following methods of solution: Successive Approximation (SA), Optimal Interpolation (OI), and 3D-Var. Analyses are given for the following parameters: zonal and meridional wind components, temperature, relative humidity, and geopotential height. The analysis package was applied to produce analyses at 6 h time interval for the period 1-11 August 2008. The period was selected for data availability and forty-one analyses were collected. The results show the validity of the different solutions, which can be chosen depending on the physical problem to solve and on the computational resources available. In particular, assuming the observations as the reference, all solutions show a decrease of the RMSE compared to the background. The decrease is consistent with the particular setting of the analysis system used in this paper. The comparison between different solutions shows that the SA converges to OI in few iterations, and that the SA solution with ten iteration is, in practice, equal to OI. Moreover, the 3D-Var method shows its potential to improve the analysis, once the horizontal and vertical length-scales and the background and observational errors are set optimally, because its solution may be sizeably different from two-dimensional methods.展开更多
基金This study is supported by the National Science and Technology Commission of China.
文摘In-situ measurement of atmospheric CO_2 was made at the top of the Waliguan Mountain(36°17′N,100°54′E,3816 m asl).where the air is not directly affected by the local anthropogenic and natural sources,by using a nondispersive infrared(NDIR)analyzer and following the procedures proposed by WMO.The CO_2 in the flask samples collected on the mountain was also analyzed in a laboratory.The measurements uncover the daily,monthly and seasonal variabilities and the baseline level of the CO_2 in the air over the“clean”area of Chinese hinterland.Results suggest that the CO_2 concentration over the East Asia continent has evident periodical variation,similar to that of global distribution.In 1992,an annual mean baseline CO_2 concentration of 356.4 ppm over the continent was obtained.The annual mean val- ue was 357.2 ppm for 1993.Some relationships between the CO_2 concentration at Waliguan and the weather conditions, especially,wind speed and direction are found through the observation.
文摘The comprehensive impact of atmospheric dry deposition and wet deposition and the pollution sources of farmlands, mining areas, and towns along the Baihe River on the water quality of Miyun reservoir is investigated from the angle of the complex sources of air-soil-water pollution processes, in the context of the 1990-2001 precipitation chemical data at Shangdianzi station-a WMO regional background air pollution monitoring station 15 km far from the Miyun reservoir, in conjunction with the atmospheric dry deposition and wet deposition data of the 2002 -2003 Beijing City Air Pollution Observation Field Experiment (BECAPEX). Analysis results suggest that the major ions in precipitation in the Miyun reservoir region in this period were SO 42-, NO 3-, NH4+ and Ca2+; wet acid deposition quantity of Miyun reservoir in the summer half year (April to September) was greater than the quantity in the winter half year (October to March), and the annual wet acid deposition in the reservoir exhibited a rising trend with the mean 1038.45 t, the maximum 1766.31 t occurred in 1996, and the minimum 604.02 t in 1994; the long-term averaged pH of atmospheric precipitation in the Miyun reservoir region was 5.20, i.e. weakly acidic, and the interannual variation of pH values displayed a falling trend. pH values of water body at various depths in the Miyun reservoir were all greater than 7.0, but they exhibited vertical and horizontal nonhomogeneity, and at the same region pH decreased vertically with depth; the 2002 and 2003 annual dustfalls in the Miyun reservoir were 13513.08 t and 3577.64 t, respectively, and the spring dustfall was the number one in a year, accounting for the 61.91% and 44.56% of the annual totals of 2002 and 2003, respectively. Because the atmospheric dry deposition and wet depositions contain multiple types heavy metal elements and harmful elements, they to some extent exacerbated the eutrophication, acidification and potential heavy metal pollution of the reservoir water. The above comprehensive analysis result
文摘This paper presents a general-purpose analysis package able to solve two- and three- dimensional analysis problems. The system can use the following methods of solution: Successive Approximation (SA), Optimal Interpolation (OI), and 3D-Var. Analyses are given for the following parameters: zonal and meridional wind components, temperature, relative humidity, and geopotential height. The analysis package was applied to produce analyses at 6 h time interval for the period 1-11 August 2008. The period was selected for data availability and forty-one analyses were collected. The results show the validity of the different solutions, which can be chosen depending on the physical problem to solve and on the computational resources available. In particular, assuming the observations as the reference, all solutions show a decrease of the RMSE compared to the background. The decrease is consistent with the particular setting of the analysis system used in this paper. The comparison between different solutions shows that the SA converges to OI in few iterations, and that the SA solution with ten iteration is, in practice, equal to OI. Moreover, the 3D-Var method shows its potential to improve the analysis, once the horizontal and vertical length-scales and the background and observational errors are set optimally, because its solution may be sizeably different from two-dimensional methods.
