珠江三角洲地区大气CO2浓度特征及地面风的作用.

By using cavity ring-down spectroscopy (CRDS) technology, the present study measured the CO2 mole fraction (1 × 10-6, ppm) for the period 2014--2016 in the Guangzhou Panyu Atmospheric Composition Site (GPACS), a suburban site in the Pearl River Delta (PRD) region of China, and the correlations of CO2 concentration with surface wind were also investigated. Results show that: (1) Atmospheric CO2 has obvious geographical inhomogeneity in the PRD region, and the annual average value of background concentration in GPACS is 22.5 ppm higher than the value in the global background area. (2) The CO2 concentration is the highest in spring, moderate in winter and autumn, and the lowest in summer, with the annual average value being 426.64 ± 15.76 ppm. The diurnal CO2 shows two peaks: one peak at 05:00--07:00 and the other at 21:00--22:00 Local Standard Time, and the minimum value appears at 13: 00--15: 00. Together, these patterns indicate that the CO2 is affected by the combined effects of anthropogenic and biogenic processes. (3) The diurnal CO2 anomaly and wind speed show a significant negative correlation (p<0.01) during spring and summer, but they show a significant positive correlation (p< 0.01) during autumn and winter. In spring and summer, winds from the directions of S-WSW and NNE-N result in lower CO2 concentrations. By contrast, in autumn and winter, winds from the directions of SSE-S and N substantially lower the CO2. Winds from the directions of NW and NE-ENE significantly increase the CO2 concentration throughout the year, and furthermore, winds from the directions of NW-NNW, and NNE-ENE contribute 0.42 ppm and 0.32 ppm to the corresponding CO2 concentration, which indicates that the CO2 may have a potential source in these sectors. [ABSTRACT FROM AUTHOR]