Retrieval Of Environmental Parameters Over Water Areas Using MODIS Data
| dc.contributor.author | Amin, Abd Rahman Mat | |
| dc.date.accessioned | 2020-02-03T06:31:18Z | |
| dc.date.available | 2020-02-03T06:31:18Z | |
| dc.date.issued | 2012-02 | |
| dc.description.abstract | In this study, new and simple algorithms to retrieve cirrus cloud, sediment and aerosol optical depth (AOD) from Moderate Resolution Radiospectrometer (MODIS) imagery is suggested and demonstrated. Techniques used in this thesis are totally new and never been used before by others researchers. The presences of cirrus cloud have been detected utilizing gradient technique algorithm. The algorithm is based on the gradient connecting the 1.38 and 1.24 μm lines of the log– log graph of apparent reflectance against the MODIS wavelength. This algorithm has been tested over the Yellow Sea, Gulf of Martaban, Mediterranean Sea and Atlantic Ocean. The result of this algorithm is then compared with the band ratio technique and the accuracy was determined with percentage difference below 10%. The presence of sediment reflectance in the MODIS imagery not only saturate the ocean color channels, but also enhance the reflectance of near infrared channels used in the atmospheric correction algorithm. This leads to the overestimation of the aerosol contributions and underestimation of the derived water-leaving reflectance in the visible channels. In this study, a new and simple method to detect and mask the presence of sediment reflectance in the MODIS imagery is proposed. The algorithm is based on the difference of the gradient of the line connecting the 0.47 and 2.13 μm channels and 0.47 and 0.66 μm channels of a log–log graph of the apparent reflectance values against their MODIS wavelengths. A sample results over Yellow Sea, Gulf of Martaban and Arabian Sea was demonstrated. The accuracy of the algorithm was tested and determined. The comparison of this algorithm with the established algorithm also showed good agreement with percentage difference less than 10%. The study of atmospheric aerosol is an important element to understand the earth’s solar radiation budget, water cycle balance, and climate change dynamics. In this study, a new and simple algorithm to estimate the AOD over water region is proposed. The AOD retrieval algorithm is based on inverse gradient of the line connecting the channels of 0.47, 1.24, 1.64 and 2.13 μm of MODIS atmospheric channels. The gradient is then compared to the AOD map of 0.869 μm that is distributed by MODIS Ocean Color team using regression technique. The result of the regression shows good agreement with R>0.90. The resulted algorithm from this technique then used to construct the AOD over water region. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/9493 | |
| dc.language.iso | en | en_US |
| dc.subject | MODIS (Spectroradiometer) | en_US |
| dc.title | Retrieval Of Environmental Parameters Over Water Areas Using MODIS Data | en_US |
| dc.type | Thesis | en_US |
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