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Determination of Spatio-Temporal Variations of Vegetation Cover, Land Surface Temperature and Rainfall and Their Relationships over Sri Lanka Using NOAA AVHRR Data
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kulawardhana, Ranjani Wasantha |
| Copyright Year | 2004 |
| Abstract | Vegetation dynamics is an important indicator of the changing climatic parameters. The use of spectral information coming from the earth observation satellites has been identified as an effective approach in climate related studies. It demands less time and effort as compared to conventional techniques including field surveying. This paper is focused on the results of the preliminary part of the study carried out with the aim of investigat ing spatio-temporal variability of vegetation cover, land surface temperature and their relationships over Sri Lanka using NOAA AVHRR data. Monthly maximum cloud free NOAA AVHRR LAC 1B data were downloaded from the satellite active archives. Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) surfaces were derived for the available images. The LST values were derived using the Split Window Algorithm. Monthly Maximum Value Composites of NDVI and LST were derived for each month. Monthly averages of rainfall were obtained from the rainfall surfaces developed with ground data. Mean pixel values of NDVI, LST and rainfall for each of the selected sample site from three major climatic zones - Dry, Intermediate and Wet- were used in simple regression analysis to establish the correlation among them. Monthly averages of the above parameters were used in studying the spatio-temporal variability of NDVI, LST and rainfall. The results of the study show that monthly average NDVI values over the island are in the range of 0.24-0.47. LST values derived are in the range of 78.67 0 F- 96.08 0 F with maximum and minimum values reported in March from the Dry Zone and in August in Wet Zone, respectively. Although a strong correlation between lag rainfall and LST could not be observed for Wet and Intermediate Zones it was significant (P<0.05) between NDVI and two month lag rainfall for the Dry Zone. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.pgia.ac.lk/files/Annual_congress/journel/v16/DeterminationoSpatio.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
