基于BRDF订正的兰州地区春季气溶胶光学厚度反演实验

利用6S模式反演并分析兰州地区春季气溶胶光学厚度(AOD)分布情况,探讨了双向反射分布(BRDF)对气溶胶光学厚度反演结果的影响.结果表明:兰州地区2010年春季气溶胶光学厚度高值中心位于西工业区和城关区,最大值分别为0.46和0.31.不考虑BRDF时水面上空气溶胶光学厚度反演结果存在明显误差,经Walthall BRDF订正后,水面上空误差明显减小,说明经过Walthall BRDF订正后的6S模式适用于水面上空的气溶胶光学厚度反演.兰州大学半干旱气候与环境观测站(SACOL)站点(35.57°N,104.08°E)反演值和实测值比较表明,在无云晴天条件下,选用Walthall BRDF模式可以提高AOD反演精度.

Retrieval of aerosol optical depth in spring over Lanzhou based on the BRDF correction

The aerosol optical depth over Lanzhou area in spring was retrieved by 6S model,with or without considering the Walthall BRDF impact on the retrieved AOD.The results showed that there were two high value centers of AOD,0.46 in the Xigu industrial district and 0.31 in the Chengguan district,Lanzhou.The retrieved AOD over the Liujiaxia reservoir manifested significant errors,which were reduced when the Walthall BRDF model was selected in 6S,suggesting that the 6S model with the Walthall BRDF model could be applied to the retrieval of AOD over water area.Comparing the inversion value with in-situ measurements over SACOL (35.57°N,104.08°E) showed that in the sunny and cloudless conditions the Walthall BRDF model could improve the inversion accuracy of AOD.