深圳光合有效辐射计算方法的初探

Primary Study on Calculating Method of Photosynthetically Radiation at Shenzhen

摘要: 2005年夏季在深圳对太阳辐射(包括光合有效辐射PAR、可见光辐射VIS、总辐射Q等)、气象参数等进行了综合观测，初步得到了PAR、VIS等的变化特征。观测表明，小时累计之比PAR/Q、VIS/Q、PAR/VIS相对稳定，其平均值分别为2.28 (2.61~1.88)、0.46 (0.57~0.38)、4.95 (5.23~4.47)，但它们均有明显的日变化和逐日变化，并受水汽、气溶胶、云等因素的影响。建立了计算PAR、VIS的经验公式以及PAR与VIS转换关系式，计算值与观测值符合较好，PAR、VIS计算值与观测值的相对偏差分别小于3.0%、4.0%。对于经验公式在不同情况下的使用做了研究。吸收因子比散射因子对PAR、VIS的传输和计算起着更重要的作用。当同时考虑这两个因子时，可以得到实际天气较好的PAR和VIS小时累计值。

Abstract: Integrated observations were made of solar radiation (including photosynthetically active radiation (PAR), visible radiation (VIS), global radiation (Q), etc.), and meteorological parameters at Shenzhen during May 29 to June 7, 2005. The ratios of hourly sums of PAR to Q, VIS to Q and PAR to VIS were relatively stable, and their averages were 2.28 (2.61 - 1.88), 0.46 (0.57 - 0.38) and 4.95 (5.23 - 4.47), respectively. They displayed evident diurnal and daily variations and were influenced by water vapor, aerosol and clouds. Empirical models for calculating hourly sums of PAR and VIS, as well as relationship between PAR and VIS were developed. The calculated PAR and VIS were in good agreement with measured, and their relative biases were less than 3.0% and 4.0%, respectively. The applications of these empirical models under different conditions were studied. The absorbing factor plays more important role than scattering factor in atmospheric radiative transfer and calculation of PAR and visible radiation. When considering both absorbing and scattering factors, the better estimations of hourly sums of PAR and visible radiation under all sky conditions were obtained.