Abstract:
The NO
2 photolysis frequency j(NO
2) is an important parameter in tropospheric chemistry. It is one of the key factors affecting the formation of ozone and OH radicals in the troposphere. The variations of j(NO
2) and solar radiation and the correlation between photolysis rate and sub-band solar radiation were analyzed using the observational data in Xianghe from November 2017 to January 2018. On this basis, a parameterized scheme suitable for reconstructing j(NO
2) in the Xianghe area was constructed. The results indicate that the variation trends of j(NO
2) and solar radiation in Xianghe are basically the same, and the diurnal variations are all unimodal with high noon and small morning and evening. The variation range of j(NO
2) in winter is 0.00046-0.0044 s
-1, with a mean of 0.0029 s
-1. Since j(NO
2) correlates well with the clear sky index (K
S) and transmittance of ultraviolet radiation (K
UV), an experimental estimating equation based on K
UV was established using the correlation between j(NO
2), air mass number, and clear air index. Considering the clear sky index K
S is more easily obtained and global radiation is a conventional observation of meteorological stations, an experimental estimating equation was established based on K
S. The instantaneous value of j(NO
2) can be estimated by the equations established using K
UV and Ks, and the mean absolute percentage errors between the instantaneous values obtained by the two equations and the observed value are 6.5% and 13.9%, and the root mean square errors are 0.00029 and 0.00051, respectively.