Journal of Resources and Ecology >
Analysis of Spatio-temporal Land Surface Temperature and Normalized Difference Vegetation Index Changes in the Andassa Watershed, Blue Nile Basin, Ethiopia
Received date: 2018-06-22
Accepted date: 2018-09-10
Online published: 2019-01-28
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Analysis of the nexus between vegetation dynamics and climatic parameters like surface temperature is essential in environmental and ecological studies and for monitoring of the natural resources. This study explored the spatio-temporal distribution of land surface temperature (LST) and Normalized Difference Vegetation Index (NDVI) and the relationship between them in the Andassa watershed from 1986 to 2016 periods using Landsat data. Monthly average air temperature data of three meteorological sites were used for validating the results. The findings of the study showed that the LST of the Andassa watershed has increased during the study periods. Overall, average LST has been rising with an increasing rate of 0.081°C per year. Other results of this study also showed that there has been a dynamic change in vegetation cover of the watershed in all seasons. There was also a negative correlation between LST and NDVI in all the studied years. From this study we can understand that there has been degradation of vegetation and intensification of LST from 1986 to 2016.
Key words: landsat data; land surface temperature (LST); NDVI; vegetation cover
Melkamu Meseret Alemu . Analysis of Spatio-temporal Land Surface Temperature and Normalized Difference Vegetation Index Changes in the Andassa Watershed, Blue Nile Basin, Ethiopia[J]. Journal of Resources and Ecology, 2019 , 10(1) : 77 -85 . DOI: 10.5814/j.issn.1674-764X.2019.01.010
Fig. 1 Location map of the study area |
Table 1 Characteristics of satellite imagery used in this study |
Satellite image | Path/row | Sensor | Resolution (m) | No. of bands | Date of acquisition |
---|---|---|---|---|---|
Landsat-5 | 170/52 | TM | 30 | 7 | 04-02-1986 |
Landsat-5 | 170/52 | TM | 30 | 7 | 11-02-2000 |
Landsat-8 | 170/52 | OLI-TIRS | 30 | 11 | 07-02-2016 |
Fig. 2 General workflow of the methodology |
Table 2 Values of parameters of Landsat images from metadata |
Variable | Description | Value | |
---|---|---|---|
(Landsat-5 TM) | (Landsat-8 OLI-TIRS) | ||
K1 | Thermal constant | 607.76 | 774.8853 |
K2 | Thermal constant | 1260.56 | 1321.0789 |
Lmin | Minimum value of Radiance | 1.238 | 0.10033 |
Lmax | Maximum value of Radiance | 15.303 | 22.00180 |
Qcalmin | Minimum Quantize Calibration | 1 | 1 |
Qcalmax | Maximum Quantize Calibration | 255 | 65535 |
Fig. 3 NDVI maps of the Andassa watershed for three different years^Note: (a) NDVI map in 1986, (b) NDVI map in 2000 and (c) NDVI map in 2016. |
Table 3 The NDVI distributions in different classes of years 1986, 2000 and 2016 |
NDVI | 1986 | 2000 | 2016 | |||
---|---|---|---|---|---|---|
Area (ha) | Percent (%) | Area (ha) | Percent (%) | Area (ha) | Percent (%) | |
<0 | 120.33 | 0.20 | 72.72 | 0.12 | 13.86 | 0.02 |
0-0.1 | 26505.09 | 43.47 | 26728.11 | 43.84 | 3292.65 | 5.40 |
0.1-0.2 | 26319.42 | 43.17 | 24039.99 | 39.43 | 40717.98 | 66.79 |
0.2-0.3 | 6464.16 | 10.61 | 7447.95 | 12.22 | 14968.26 | 24.55 |
0.3-0.4 | 1367.91 | 2.24 | 2197.08 | 3.60 | 1838.52 | 3.02 |
>0.4 | 190.98 | 0.31 | 482.04 | 0.79 | 136.62 | 0.22 |
Fig. 4 LST maps of the Andassa watershed for three different years: (a) 1986, (b) 2000 and (c) 2016 |
Table 4 Summary statistics of LST of the study area for different years. |
Year | Min | Q1 | Mean | Q2 | Q3 | Max | Sd |
---|---|---|---|---|---|---|---|
1986 | 13.78 | 28.77 | 30.58 | 30.42 | 32.46 | 39.16 | 3.06 |
2000 | 14.25 | 29.18 | 30.77 | 31.24 | 32.86 | 39.16 | 2.79 |
2016 | 17.39 | 31.20 | 32.88 | 33.08 | 34.88 | 40.64 | 2.86 |
Fig. 5 Boxplots of LST for the years 1986, 2000 and 2016 |
Fig. 6 Map showing percentage change in LST between the years 1986 and 2016 |
Table 5 Correlation between LST, NDVI and elevation |
Year | LST and NDVI | LST and Elevation | NDVI and Elevation |
---|---|---|---|
1986 | -0.43 | -0.07 | -0.11 |
2000 | -0.50 | -0.28 | -0.03 |
2016 | -0.46 | -0.40 | -0.06 |
The authors have declared that no competing interests exist.
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