排序方式： 共有13条查询结果，搜索用时 15 毫秒
11.
Direct Radiative Effect of Aerosols on Net Ecosystem Carbon Exchange in the
Pearl River Delta Region
The environmental impact of aerosols is currently a hot issue that has received worldwide attention. Lacking simultaneous observations of aerosols and carbon flux, the understanding of the aerosol radiative effect of urban agglomeration on the net ecosystem carbon exchange(NEE) is restricted. In 2009-2010, an observation of the aerosol optical property and CO_2 flux was carried out at the Dongguan Meteorological Bureau Station(DMBS) using a sun photometer and eddy covariance systems. The different components of photosynthetically active radiation(PAR),including global PAR(GPAR), direct PAR(DPAR), and scattered PAR(FPAR), were calculated using the Santa Barbara DISORT Atmospheric Radiative Transfer(SBDART) model. The effects of PAR on the NEE between land-atmosphere systems were investigated. The results demonstrated that during the study period the aerosol optical depth(AOD)reduced the DPAR by 519.28±232.89 μmol photons · m~(-2)s~(-1);, but increased the FPAR by 324.93±169.85μmol photons ·m~(-2)s~(-1);, ultimately leading to 194.34±92.62 μmol photons · m~(-2)s~(-1); decrease in the GPAR. All the PARs(including GPAR,DPAR, and FPAR) resulted in increases in the NEE(improved carbon absorption), but the FPAR has the strongest effect with the light use efficiency(LUE) being 1.12 times the values for the DPAR. The absorption of DPAR by the vegetation exhibited photo-inhibition in the radiation intensity 600 photons · m~(-2)s~(-1); in contrast, the absorptions of FPAR did not exhibit apparent photo-inhibition. Compared with the FPAR caused by aerosols, the DPAR was not the primary factor affecting the NEE. On the contrary, the increase in AOD significantly increased the FPAR, enhancing the LUE of vegetation ecosystems and finally promoting the photosynthetic CO_2 absorption. 相似文献
12.
为广东省气象要素、大气成分观测站网优化提供依据，利用广东省86个国家气象观测站的风速、相对湿度、气温以及降水等30年气候资料，结合气候相似性理论论证了全省不同区域的综合气象因子代表站。结果表明：(1)连平站、惠来站、高州站和番禺气象局站的欧氏距离较小，气象要素理论值与观测值的相对误差平均值为3.55%,可分别作为广东省粤北、粤东、粤西和珠三角区域综合气象代表站；(2)21个地市拟选站的气象要素理论值与观测值的相对误差平均值为3.474%,可作为地市级综合气象因子代表站；(3)除了高州站之外，其它3个区域代表站与地市级拟选代表站未出现重叠，因此可以合理布局、优化区域和地市级代表站的规划设计方案。 相似文献
13.