| Author: | Li, Jing |
| Title: | Satellite detection and retrieval of Asian dust storms using MTSAT imageries |
| Advisors: | Wong, Man-sing Charles (LSGI) |
| Degree: | M.Sc. |
| Year: | 2017 |
| Subject: | Dust storms -- Remote sensing Artificial satellites Hong Kong Polytechnic University -- Dissertations |
| Department: | Faculty of Construction and Environment Department of Land Surveying and Geo-Informatics |
| Pages: | vii, 62 pages : color illustrations |
| Language: | English |
| Abstract: | In this paper, by analyzing 2008, 2009 and 2012 dust storms cases with MTSAT observations, an integrated algorithm is developed based on spectral threshold and uniformity texture tests and can be used successfully in both daytime and nighttime. Detailed examinations of the threshold tests are performed along with explanations of the physical basis. The thermal radiation transfer through the single dust layer is performed with the widely used forward model SBDART to construct the Look-up Table (LUT). From the sensitivity study, it is found that when Land Surface Temperature, Dust layer height, water vapor amount and satellite zenith angle are fixed, brightness temperature (BT) has a quasi-linear relationship with AOT and BTD11-12 has a quasi-linear relationship with effective radius (Reff) thus dust aerosol optical thickness and effective radius can be retrieved simultaneously in LUTs. From the LUT analysis, it can be conclude that dust pixels locate around the edge of LUTs are not likely to be retrieved correctly while dust pixels located at the middle part of a LUT are likely to be retrieved correctly. This implies that this retrieval method may not perform well when retrieving dust plumes and very heavy dust storms normally over desert. What's more, the BTDs of dust cloud over desert area is much more negative than it really be, because of the contribution of negative BTD from desert. Thus it performs not well over desert area (mainly Taklimakan desert). This retrieval algorithm is explored for the application of five dust events occurred in 2008, 2009 and 2012 observed by MTSAT. These dust events mainly located at Gobi and Bohai nearby regions. AERONET AOT and Reff and MODIS AOT are used to validate dust case results at Bohai nearby areas. Both MODIS AOT and AERONET AOT and Reff show good agreement with MTSAT retrieved AOT and Reff. While for dust cases at Gobi regions, only MODIS AOT can be used for validation. The MTSAT retrieved AOTs and MODIS AOTs shows reasonable agreement. The distribution pattern of Reff results are very reasonable for the dust cases over Gobi regions. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 991022385850803411.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 8.28 MB | Adobe PDF | View/Open |
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