The Improvement of AOD Retrieval and Application to High Temporal and Spatial Fused Imagery for Air Quality Monitor
| Autor: | Ren-Wei Kuo, 郭人維 |
|---|---|
| Rok vydání: | 2019 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 Aerosol Optical Depth (AOD) is an important indicator of air quality. Through satellite observation, we can obtain comprehensive information on AOD in broad spatial distribution. However, since the characteristics of aerosols are both short-lived and regional, and that getting high spatial and temporal AOD information by single satellite observation is not feasible as well. Adopting the spatial-temporal image fusion technique, like Spatial-Temporal Adaptive Reflectance Fusion Model (STARFM), becomes one of the desirable approaches to deal with the dilemma. Nevertheless, this model was designed for image fusion on surface reflectance data. Hence, revising the STARM model to retain the information from the atmosphere is necessary if we want to apply it on air quality monitoring. Moreover, we use an algorithm called Simultaneous Radiation Solution (SRS) to retrieve AOD. To correct the limitation of SRS, which is only applicable for low surface reflectance area, we modify the SRS in this research and further apply it on a higher surface reflectance area. In short, we get high spatial and temporal AOD information through STARFM and SRS. After applying the new high spatial and temporal algorithm on three air pollution cases in Taiwan, the spatial distribution of the results correspond with the MODIS Dark Target AOD product in 3km resolution. We further use the AERONET data to validate our retrieval, and it shows that there are 63%, 75% and 80% of retrieved AOD for each case located in expected error respectively. However, a significant error appears in some specific areas. By preliminary analysis, we assume that the error comes from the wrong estimation of surface reflectance and poor handling on bidirectional reflectance distribution function (BRDF) in this research. If the BRDF for different land cover types is constructed, the retrieval of AOD should be improved. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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