关于硝酸盐气溶胶光学特征和辐射强迫的研究进展

在过去的20多年里，中外对硫酸盐气溶胶做了大量的研究，对它在大气中的排放、含量、光学特征和辐射强迫有了深入的认识；由于硝酸盐气溶胶在大气中平均含量比硫酸盐低很多，因此过去人们对硝酸盐的研究没有给予重视。然而，近年来的研究表明，硝酸盐气溶胶的散射性质在某些波段甚至强于硫酸盐；同时，由于未来对人为硫酸盐前体物的减排，硫酸盐气溶胶排放会大幅度减少，而硝酸盐气溶胶的排放却增长迅速，其在人为气溶胶中所占的比重越来越高，将会导致其在未来造成的辐射强迫有可能超过硫酸盐，使得其在地区范围内和季节尺度上成为重要的辐射强迫和气候影响因子。中国是硝酸盐气溶胶排放量较大的地区，硝酸盐对未来中国气候和气候变化的影响显得越来越重要。因此，就近年来有关硝酸盐气溶胶的排放和在大气中的浓度变化、光学厚度分布特征及其辐射强迫的研究进展做了回顾和介绍，并对其未来的研究做了展望。

Advances in the research of optical properties and radiative forcing of nitrate aerosols

Many researches on sulfate aerosols have been done in the last two decades, which contributed significantly to our understanding of the emission, concentration, optical properties and radiative forcing of sulfate in the atmosphere. However, not much attention was paid to the studies on nitrate at the beginning since the concentration of nitrate aerosol in the atmosphere was much less than that of sulfate aerosol. Recent studies show that the scattering properties of nitrate are even stronger than that of sulfate in some wave bands. Besides, the proportion of nitrate in total anthropogenic aerosols shows an increasing trend since the emissions of sulfate aerosol have been greatly reduced due to the controlling to its precursors at present, while the emissions of nitrate aerosol increase rapidly, leading to higher radiative forcing caused by nitrate than by sulfate. It is very likely that nitrate aerosol will become an important radiative forcing factor that will affect climate change at regional and seasonal scales in the future, especially over China due to the increasing large emission. Therefore, the present paper reviews the researches on nitrate aerosols from the perspectives of emission, concentration change, distribution of optical depth, and radiative forcing. Finally, the direction of research on nitrate aerosols in the future is discussed.