Tie Xuexi, Li Guohui, Ying Zhuming, Guenther Alex, Madronich Sasha
National Center for Atmospheric Research, Boulder, CO, USA.
Sci Total Environ. 2006 Dec 1;371(1-3):238-51. doi: 10.1016/j.scitotenv.2006.06.025. Epub 2006 Oct 4.
In this study, a regional dynamical model (WRF) is used to drive biogenic emission models to calculate high resolution (10x10 km) biogenic emissions of isoprene (C(5)H(8)), monoterpenes (C(10)H(16)), and nitric oxide (NO) in China. This high resolution biogenic inventory will be available for the community to study the effect of biogenic emissions on photochemical oxidants in China. The biogenic emissions are compared to anthropogenic emissions to gain insight on the potential impact of the biogenic emissions on tropospheric chemistry, especially ozone production in this region. The results show that the biogenic emissions in China exhibit strongly diurnal, seasonal, and spatial variations. The isoprenoid (including both isoprene and monoterpenes) emissions are closely correlated to tree density and strongly vary with season and local time. During winter (January), the biogenic isoprenoid emissions are the lowest, resulting from lower temperature and solar radiation, and highest in summer (July) due to higher temperature and solar radiation. The biogenic NO emissions are also higher during summer and lower during winter, but the magnitude of the seasonal variation is smaller than the emissions of isoprene and monoterpenes. The biogenic emissions of NO are widely spread out in the northern, eastern, and southern China regions, where high-density agricultural soil lands are located. Both biogenic NO and isoprenoid emissions are very small in western China. The calculated total biogenic emission budget is smaller than the total anthropogenic VOC emission budget in China. The biogenic isoprenoid and anthropogenic VOC emissions are 10.9 and 15.1 Tg year(-1), respectively. The total biogenic and anthropogenic emissions of NO are 5.9 and 11.5 Tg(NO) year(-1), respectively. The study shows that in central eastern China, the estimated biogenic emissions of isoprenoids are very small, and the anthropogenic emissions of VOCs are dominant in this region. However, in northeastern and southern China, there are relatively large biogenic emissions of isoprenoids, leading to an important impact on the ozone production in these regions. Furthermore, the emissions of isoprenoids are highest during summer and noontime, which correlates to the peak of ozone production period. For example, the ratio between summer and winter for the emissions of isoprenoids is about 15 in China. As a result, the biogenic emissions of isoprenoids are significantly larger than the anthropogenic emissions of VOCs in China during daytime in summer. Biogenic NO emissions are mostly produced by agricultural soils which co-exist with large populations and human activity. As a result, the biogenic emissions of NO are mostly overlapped with the anthropogenic emissions of NO, leading to the enhancement in NO concentrations in the high anthropogenic NO emission regions. Finally, the future emissions of isoprene and monoterpenes over China are estimated. The results show that the future biogenic emissions may increase significantly due to land cover changes in central eastern China, which could have a very important impact on ozone formation in this region. However, these estimates are highly uncertain and are presented as a potential scenario to show the importance of possible changes of biogenic emissions in China.
在本研究中，使用区域动力模型（WRF）驱动生物源排放模型，以计算中国高分辨率（10×10千米）的异戊二烯（C₅H₈）、单萜烯（C₁₀H₁₆）和一氧化氮（NO）的生物源排放。这个高分辨率生物源排放清单将可供科学界研究生物源排放在中国对光化学氧化剂的影响。将生物源排放与人为排放进行比较，以深入了解生物源排放在对流层化学，特别是该地区臭氧生成方面的潜在影响。结果表明，中国的生物源排放在日变化、季节变化和空间分布上都有显著差异。类异戊二烯（包括异戊二烯和单萜烯）排放与树木密度密切相关，并随季节和当地时间有很大变化。在冬季（1月），由于温度和太阳辐射较低，生物源类异戊二烯排放最低；而在夏季（7月），由于温度和太阳辐射较高，排放最高。生物源NO排放在夏季也较高，冬季较低，但季节变化幅度小于异戊二烯和单萜烯的排放。生物源NO排放在中国北方、东部和南方高密度农业土壤分布的地区广泛分布。中国西部的生物源NO和类异戊二烯排放都非常少。计算得出的生物源排放总量小于中国的人为挥发性有机物排放总量。生物源类异戊二烯和人为挥发性有机物排放分别为10.9和15.1太克/年。生物源和人为源NO的排放总量分别为5.9和11.5太克（NO）/年。研究表明，在中国中东部地区，估计的生物源类异戊二烯排放非常少，该地区挥发性有机物的人为排放占主导地位。然而，在中国东北和南部地区，生物源类异戊二烯排放相对较大，对这些地区的臭氧生成有重要影响。此外，类异戊二烯排放在夏季和中午最高，这与臭氧生成高峰期相关。例如，中国类异戊二烯排放的夏季与冬季之比约为15。因此，在夏季白天，中国生物源类异戊二烯排放显著大于挥发性有机物的人为排放。生物源NO排放主要由与大量人口和人类活动共存的农业土壤产生。因此，生物源NO排放大多与人为源NO排放重叠，导致高人为源NO排放地区的NO浓度升高。最后，对中国未来的异戊二烯和单萜烯排放进行了估计。结果表明，由于中国中东部地区土地覆盖变化，未来生物源排放可能会显著增加，这可能对该地区的臭氧形成产生非常重要的影响。然而，这些估计存在很大不确定性，仅作为一种潜在情景呈现，以表明中国生物源排放可能变化的重要性。
