长江中下游浅水湖泊紫外辐射的衰减

基于对长江中下游22个浅水湖泊有色可溶性有机物吸收的测量,运用经验模式估算了紫外辐射(UV-B、UV-A)在长江中下游湖泊的衰减及对应的穿透深度,并利用在武汉东湖实测的紫外辐射衰减进行了检验.结果表明,UV-B波段的320nm和UV-A波段的380nm衰减系数变化范围分别为2.05～21.00m^-1,1.07～12.85m^-1,对应的1%穿透深度分别为0.22～2.25m,0.36～4.29m.估算得到的紫外辐射衰减系数与DOC浓度均存在显著性正相关,但UV-B波段要高于UV-A波段.武汉东湖实测的紫外辐射衰减检验发现,基于CDOM吸收系数估算UV-B辐射衰减较为精确,而由于浮游植物吸收和悬浮物散射等影响对UV-A波段估算精度则明显下降.

The attenuation of ultraviolet radiation in shallow lakes in the middle and lower reaches of Yangtze River

Based on the measurement of chromophoric dissolvable organic matter in 22 shallow lakes in the middle and lower reaches of Yangtze River, the attenuation of ultraviolet radiation (UV-B, UV-A) in the lakes in the middle and lower reaches of Yangtze River and corresponding penetrating depth were estimated using empirical models; and checked up utilizing the field measured attenuation of ultraviolet radiation in Lake Donghu Wuhan. The change range of attenuation coefficients of UV-B wave band (320nm) and UV-A wave band (380nm) was 2.05~21.00m-1 and 1.07~12.85m-1 respectively; and the corresponding 1% penetrating depths were 0.22~2.25m and 0.36~4.29m respectively. The estimated ultraviolet radiation attenuation coefficient and DOC concentration all existed markedly positive relationship; but UV-B wave band was higher than UV-A wave band. The field check of ultraviolet radiation attenuation in Lake Donghu, Wuhan showed that the estimation of attenuation of UV-B radiation was more accurate based on CDOM coefficient; while the estimation accuracy of UV-A wave band decreased obviously due to the influence of phytoplankton absorption and suspended substance scattering.