Preliminary Retrieval of Aerosol Optical Depth from All-sky Images |
| |
Authors: | HUO Juan and LU Daren |
| |
Institution: | Key Laboratory for Atmosphere and Global Environment Observation, Chinese Academy of Sciences, Beijing 100029,Key Laboratory for Atmosphere and Global Environment Observation, Chinese Academy of Sciences, Beijing 100029 |
| |
Abstract: | The relationship between the radiance ratio (radiance at wavelength
450 nm to 650 nm) and aerosol optical depth (AOD) is analyzed in this paper by
numerical simulation and a ``LUT' (look-up table) approach is then presented
for the retrieval of AOD from the radiance ratio. In this LUT approach, the AOD
retrieval error depends mainly on the assumption of aerosol types. From the
preliminary simulation, a typical error of 15%--20% in AOD obtained from
the radiance ratio is estimated, due to neglecting changes in the ground albedo
and background atmosphere. At its worst, the AOD error reached a maximum of
around 50%, which will be refined in the future. In the latter part of the
paper, comparisons are made between AOD from the imager and from the CE-318 sun
photometer, both located at Xianghe observatory in Hebei Province
(39.75oN, 116.96oE). This field experiment shows that AOD from
the imager is highly correlated with AOD from the sun photometer, with a
correlation coefficient of 0.95 and an average retrieval error of around 7%.
A contrast experiment confirms the feasibility of retrieving AOD from all-sky
images, but more analysis and future research are required to improve the
accuracy. |
| |
Keywords: | all-sky image aerosol AOD radiance ratio |
本文献已被 CNKI 维普 万方数据 SpringerLink 等数据库收录! |
| 点击此处可从《大气科学进展》浏览原始摘要信息 |
| 点击此处可从《大气科学进展》下载免费的PDF全文 |
|