太陽直達光観測による奈良盆地におけるエアロゾルの地域特性

抄録

Atmospheric aerosols, produced by anthropogenic activities or natural phenomena, often cause serious air pollution with impacts on human health and the environment. However, the distribution of ground-based aerosol observation network sites such as SKYNET is not necessarily dense and uniform. The Nara Basin, located in the northwestern part of Nara Prefecture in the center of the Kinki region, is surrounded on all sides by mountains and hills. Thus, although it is easy for pollutants to remain in the area, few studies have been conducted at this site compared to other basins. Nara Women’s University is located in the northeastern part of the Nara Basin, and we have conducted long-term ground-based observations of aerosols there using a portable sunphotometer (Microtops II). In this study, we report the regional characteristics of aerosols in the Nara Basin by comparing the results of Microtops II observations there with those of SKYNET observations in Sendai. We first conducted synchronous observations of Microtops II and SKYNET in Sendai. The results showed that the values of aerosol optical thickness (AOT) from Microtops II and SKYNET were consistent. Based on this, the AOT and Ångström exponents in the Nara Basin and Sendai were compared using Microtops II and SKYNET. The results suggested that the aerosols in the Nara Basin tended toward a lower aerosol loading and a predominance of coarser particles than in Sendai. Thus, Microtops II is generally capable of capturing aerosol behavior, and has the potential to enable long-term ground-based observations in areas such as Nara where there are currently no network sites, and thus further our understanding of aerosol distribution in more diverse areas.