Analysis of the cooling effects of urban green spaces in mitigating micro-climate change using geospatial techniques in Adama City, Ethiopia

Figures & data

Figure 1. Location map of Adama City.

Table 1. Data types and sources

No.	Data category	Source	Purpose
1	Landsat images	USGS	For LU/LCC, LST, NDVI and, NDBI analysis
2	Temperature data	National meteorological agency (NMA), Ethiopia	To validate the value of temperature retrieved from satellite image
3	Adama city shape file	Adama city municipality	For preparation of result map

Table 2. Remote sensing images

Image	Path	Raw	Pixel size	Acquisition date	Sources
Landsat ETM+ of 2000	167	54	30 × 30	11, Feb, 2000	U.S. Geological Survey
Landsat OLI/TIRS of 2013 & 2023	167	54	30 × 30	05, Jan, 2023	U.S. Geological Survey

Figure 2. Methodological flow chart.

Table 3. Software used for the study

No	Software	Purpose
1	ArcGIS 10.3	Analyzing and visualization of spatial data
2	ERDAS 2015	For Image classification and accuracy assessment
3	Google Earth Pro & GPS	For LULC accuracy assessment

Table 4. Accuracy assessment of land use and land cover for 2000, 2013 and 2023

LU/LC class	2000		2013		2023
	Producers accuracy	Users accuracy	Producers accuracy	Users accuracy	Producers accuracy	Users accuracy
	(%)	(%)	(%)	(%)	(%)	(%)
Dense veg.	94.5	98.3	99.3	99.8	98.6	99.8
Built-up	98.8	95.9	98.9	97.4	97.3	98.22
Open space	100	99.4	100	99.4	100	98.4
Sparse veg.	99.5	99.5	43.2	97.2	92.6	98
Water bodies	98.6	99.8	99.3	98.3	94.5	99.8
Overall accuracy	98.4%		97.6%		98.7%
Kappa coefficient	0.96		0.97		0.97

Figure 3. LU/LC maps of the year 2000 (A), 2013 (B) and 2023(C).

Table 5. Land Use/land cover (LU/LC) of the Year 2000, 2013 and 2023

Class name	2000		2013		2023
	Area (lkm^2)	(%)	Area (km^2)	(%)	Area (km^2)	(%)
Dense veg.	29.38	21.26	24.14	17.47	18.17	13.15
Built-up	31.75	22.97	67.13	48.57	86.0	62.24
Open Space	2.26	1.64	3.17	2.29	0.36	0.26
Sparse veg.	72.88	52.74	41.34	29.92	32.27	23.35
Water body	1.93	1.40	2.42	1.74	1.38	1.00
Total	138.2	100.00	138.2	100.00	138.2	100.00

Table 6. Summary of LST values of the year 2000, 2013 and 2023

LST Values (^0C)	Landsat ETM+ (2000)	Landsat ETM+ (2013)	Landsat OLI (2023)
Minimum	19	17.8	18.8
Maximum	36.4	38.2	39.7
Mean	27.08	28.25	31.78

Figure 4. LST map of the year 2000(A) and 2013(B) and 2023(C).

Table 7. Variations of LST values from the year 2000 to 2023

2000			2013		Difference (%)
LST (^0C)	Area (km^2)	Area (%)	Area (km^2)	Area (%)	Difference (km^2)	2000–2023
<22	24.57	17.78	36.72	26.57	12.15	+10.42
22–26	64.51	46.69	32.84	23.76	−31.67	− 22.93
26–30	29.33	21.22	14.04	10.16	−15.29	− 11.06
30–34	8.23	5.95	38.97	28.2	30.74	+20.62
>34	11.54	8.35	15.63	11.31	4.09	+2.96

Figure 5. Built-up areas of Adama City in 2000 (A), 2013 (B) and 2023 (C).

Figure 6. Relationship between LST and NDBI.

Figure 7. Normalized difference vegetation index for the year 2000(A), 2013(B) and 2023(C).

Table 8. Comparisons of the NDVI values in the year 2000 and 2023

NDVI values	Landsat ETM+ (2000)	Landsat ETM+ (2013)	Landsat OLI (2023)
Min.	−0.31	−0.265	−0.128
Max.	0.62	0.516	0.456
Mean	0.35	0.28	0.124

Figure 8. Relationship between LST and NDVI.

Figure 9. Estimation of LST in the selected test spot in Adama City.

Table 9. Estimated LST value of selected test spot (Gooba Hiddii Kebele)

Increase of built-up area by	Estimated mean LST in (°C)	Increase green area by	Estimated mean LST (°C)
25%	35.02	25%	32.98
50%	35.78	50%	31.76
75%	36.54	75%	30.46
100%	37.31	100%	29.16

Figure 10. Relationship between change in LST (°C) and green space area (ha).

Figure 11. LST change with respect to areas of green spaces.

Figure 12. Heat contribution index of LU/LC of the years 2000 and 2023.