Bound, Alice Jayne;
(1999)
The development and use of satellite remote sensing techniques for the monitoring and hydrological modelling of the Sudd Marshes.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The monitoring and modelling of the world's large remote wetlands is important both hydrologically and climatically. Satellite remote sensing offers the only realistic possibility of making the necessary long term regular measurements of such wetlands. Using the Sudd as a case study, the aim of this work was therefore to develop and extend satellite remote sensing techniques, and to develop methods for applying the resulting data to a hydrological model. A 3-year record of area measurements of the Sudd was demonstrated using thermal imagery from the Advanced Very High Resolution Radiometer (AVHRR) with monthly measurements during cloud free dry-season periods. The assumption of full pixel coverage was supported by high resolution Landsat data. During the wet season, however, thermal imagery was always found to be limited due to clouds and poor land/wetland contrast. Therefore the use of microwave instruments which are unaffected by cloud was investigated. Synthetic Aperture Radar imagery was found to be unable to distinguish vegetated swamp. However, radar altimeter measurements were used to obtain the water level variation and the along-track extent of the wetland. A relationship between wetland area and extent was found so the area can be determined using radar altimeters. The area record was used to validate a simple hydrological model of the Sudd with the main input parameters being obtained by remote sensing techniques. It was found that input and output river flow could be accurately inferred from radar altimeter measurements near sites with a known rating curve. Good agreement with the measured areas was obtained by adjusting the rainfall and evaporation estimates by ~ 10% but with other parameters unadjusted. The model predicts that the completion of the Jonglei Canal would reduce the Sudd area to 70% of its current value on a timescale of three years.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | The development and use of satellite remote sensing techniques for the monitoring and hydrological modelling of the Sudd Marshes |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Thesis digitised by ProQuest. |
| Keywords: | Earth sciences; Wetlands |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10123995 |
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