广州地区光化辐射通量与辐照度的特征

Characterization of actinic flux and irradiances over Guangzhou region

应用NCARTUV辐射模式与地表实际观测分析了理论上广州地区地表可获得的最强光化辐射通量、辐照度及其波谱变化特征与月、日变化特征,计算与观测的差异用于评估气溶胶对紫外辐射通量的作用.结果表明,光化辐射通量与辐照度均具有正弦曲线的日变化特征,但光化辐射通量的正弦波形较辐照度的更为宽广,其辐射强度随太阳天顶角的增加下降幅度也更为缓慢;光化辐射中的总能量可见光谱区约占86%,紫外谱区仅占约14%;理论计算与实际观测表明,不同监测波段范围的紫外辐射表,虽然其标识均为监测UVA或UVB的辐射,但差异明显;广州地区的气溶胶污染显著影响紫外辐射通量.由于紫外辐射通量是影响对流层臭氧生产力的关键因子,有必要更加深入地认识广州地区气溶胶与紫外辐射通量的相互作用.

The surface actinic flux peak,the magnitude and spectrum of irradiance and diurnal/seasonal variations over the Guangzhou region were studied by analyzing the surface measurements and by using NCAR TUV radiative model.The difference between the calculation and observation were used to assess the effect of aerosol particles on ultraviolet radiation（UV） flux.The diurnal features of actinic flux and irradiance had the same patterns as the Sine-curve,but the Sine shape of actinic flux was wider than that of irradiance,and the radiation intensity of actinic flux also dropped more slowly with the increasing of solar zenith angle than that of irradiance.The total energy of actinic flux took up about 86% in the visible spectrum while only about 14% in the ultraviolet spectrum.The theoretical calculation and observation showed that the differences were obvious by using different radiometers covering different spectra,although the radiometers were labeled as UVA or UVB radiometers.The aerosol particles significantly affected the UV flux over the Guangzhou region.Because UV flux was a key factor to influence tropospheric ozone production,the better understanding of the interactions between UV flux and aerosol particles was needed over the Guangzhou region.