International Journal of Environmental Protection and Policy

Submit a Manuscript

Publishing with us to make your research visible to the widest possible audience.

Propose a Special Issue

Building a community of authors and readers to discuss the latest research and develop new ideas.

The Subsurface Urban Heat Island Intensity in Enugu Urban, Nigeria

Urbanisation over the past hundred years has caused environmental and thermal influences underground; yet little knowledge exists about subsurface warming in Enugu, despite previous studies confirming the presence of urban heat island in the area. This study analysed the subsurface urban heat island intensity in Enugu urban, using secondary urban subsoil temperature data set that was sourced from the Nigerian Meteorological Agency over 21 years (2000-2020). With an application known as grid, the rural subsoil temperature data set was gotten by downscaling that of the urban which is 40 km away. The statistical technique employed was Welch’s t-test. The study showed that the annual mean urban subsoil temperatures were generally warmer than that of the rural subsoil temperatures, with a mean difference or subsurface urban heat island intensity of 0.4°C. From the study, it was clear that the urban heat island effect occurred in the subsurface in Enugu, as it does above the ground. This study, to define urban and rural better, suggests that the use of the Local Climate Zone classification scheme should be considered in further research. A joint investigation of the three urban heat island categories in Enugu should also receive top priority in subsequent studies.

Enugu, Subsurface, Urban Heat Island Intensity, Urbanisation, Welch’s T-test

Francis Chibuike Nwalozie, Ifeanyi Christian Enete. (2023). The Subsurface Urban Heat Island Intensity in Enugu Urban, Nigeria. International Journal of Environmental Protection and Policy, 11(4), 57-62. https://doi.org/10.11648/j.ijepp.20231104.11

Copyright © 2023 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1. Zhu, K. (2013). Urban heat island in the subsurface and geothermal potential in urban areas [Doctoral dissertation, Eberhard Karls University of Tübingen]. Eberhard Karls University of Tübingen Bibliography. https://bibliographie.uni-tuebingen.de/xmlui/bitstream/handle/10900/49959/Zhu.pdf
2. Enete, I. C., & Alabi, M. O. (2012). Characteristics of urban heat island in Enugu during rainy season. Ethiopian Journal of Environmental Studies and Management, 5 (4), 391-396. https://doi.org/10.4314/ejesm.v5i4.8
3. National Bureau of Statistics. (2012). Annual abstract of statistics, 2012. https://www.nigerianstat.gov.ng/pdfuploads/annual_abstract_2012.pdf
4. Enete, I. C. (2015). Urban heat island research of Enugu urban: A review. International Journal of Physical and Human Geography, 3 (2), 42-48.
5. Taylor, C. A., & Stefan, H. G. (2009). Shallow groundwater temperature response to climate change and urbanization. Journal of Hydrology, 375 (3-4), 601-612. https://doi.org/10.1016/j.jhydrol.2009.07.009
6. Santos, F., Abney, R., Barnes, M., Bogie, N., Ghezzehei, T. A. Jin, L... Berhe, A. (2019). The role of the physical properties of soil in determining biogeochemical responses to soil warming. In J. E. Mohan (Ed.), Ecosystem consequences of soil warming: Microbes, vegetation, fauna and soil biogeochemistry (pp. 209-244). Academic Press. https://doi.org/10.1016/B978-0-12-813493-1.00010-7
7. Enete, I. C., Officha, M., & Ogbonna, C. E. (2012). Urban heat island magnitude and discomfort in Enugu urban area, Nigeria. Journal of Environment and Earth Science, 2 (7), 77-82.
8. Oke, T. R., Mills, G., Christen, A., & Voogt, J. A. (2017). Urban climates. Cambridge University Press. https://doi.org/10.1017/9781139016476
9. Zhan, W., Ju, W., Hai, S., Ferguson, G., Quan, J., Tang, C.-S... Kong, F. (2014). Satellite-derived subsurface urban heat island. Environmental Science &Technology, 48 (20), 12134-12140. https://doi.org/10.1021/es5021185
10. Benz, S. A. (2016). Human impact on groundwater temperatures [Doctoral dissertation, Karlsruhe Institute of Technology]. KITopen Repository. https://doi.org/10.5445/IR/1000065105
11. Turkoglu, N. (2010). Analysis of urban effects on soil temperature in Ankara. Environmental Monitoring and Assessment, 169, 439-450. https://doi.org/10.1007/s10661-009-1187-z
12. Tang, C.-S., Shi, B., Gao, L., Daniels, J. L., Jiang, H.-T., & Liu, C. (2011). Urbanization effect on soil temperature in Nanjing, China. Energy and Buildings, 43 (11), 3090-3098. https://doi.org/10.1016/j.enbuild.2011.08.003
13. Liu, C., Shi, B., Tang, C.-S., & Gao, L. (2011). A numerical and field investigation of underground temperatures under urban heat island. Building and Environment, 46 (5), 1205-1210. https://doi.org/10.1016/j.buildenv.2010.12.015
14. Shi, B., Tang, C.-S., Gao, L., Liu, C., & Wang, B.-J. (2012). Observation and analysis of the urban heat island effect on soil in Nanjing, China. Environmental Earth Sciences, 67, 215-229. https://doi.org/10.1007/s12665-011-1501-2
15. Ferguson, G., & Woodbury, A. D. (2007). Urban heat island in the subsurface. Geophysical Research Letters, 34 (23), Article L23713. https://doi.org/10.1029/2007GL032324
16. Menberg, K., Bayer, P., Zosseder, K., Rumohr, S., & Blum, P. (2013). Subsurface urban heat islands in German cities. Science of The Total Environment, 442, 123-133. https://doi.org/10.1016/j.scitotenv.2012.10.043
17. Taniguchi, M., Uemura, T., & Jago-on, K. (2007). Combined effects of urbanization and global warming on subsurface temperature in four Asian cities. Vadose Zone Journal, 6 (3), 591-596. https://doi.org/10.2136/vzj2006.0094
18. Yamano, M., Goto, S., Miyakoshi, A., Hamamoto, H., Lubis, R. F., Monyrath, V., & Taniguchi, M. (2009). Reconstruction of the thermal environment evolution in urban areas from underground temperature distribution. Science of The Total Environment, 407 (9), 3120-3128. https://doi.org/10.1016/j.scitotenv.2008.11.019
19. Okeke, F. O., Sam-Amobi, C. G., & Okeke, F. I. (2020). Role of local town planning authorities in building collapse in Nigeria: Evidence from Enugu metropolis. Heliyon, 6 (7), Article e04361. https://doi.org/10.1016/j.heliyon.2020.e04361
20. Peel, M. C., Finlayson, B. L., & McMahon, T. A. (2007). Updated world map of the Köppen-Geiger climate classification. Hydrology and Earth System Sciences, 11 (5), 1633-1644. https://doi.org/10.5194/hess-11-1633-2007
21. Ogbonna, C. E., Ugbogu, O. C., Otuu, F. C., Ohakwe, J., & Inya-Agha, S. I. (2014). Assessment of lead content of leaves of some roadside trees in Enugu urban; Environmental health implications. International Journal of Environmental Biology, 4 (1), 6-9.
22. Anyadike, R. N. C. (2002). Climate and vegetation. In G. E. K. Ofomata (Ed.), A survey of the Igbo nation (p. 73). Africana First Publishers.
23. Adefolalu, D. O. (1986). Further aspects of Sahelian drought as evident from rainfall regime of Nigeria. Archives for Meteorology, Geophysics, and Bioclimatology, Series B: Theoretical and Applied Climatology, 36, 277-295. https://doi.org/10.1007/BF02263134
24. Benz, S. A., Bayer, P., Goettsche, F. M., Olesen, F. S., & Blum, P. (2016). Linking surface urban heat islands with groundwater temperatures. Environmental Science & Technology, 50 (5), 70-78. https://doi.org/10.1021/acs.est.5b03672
25. Benz, S. A., Bayer, P., & Blum, P. (2017). Global patterns of shallow groundwater temperatures. Environmental Research Letters, 12 (3), Article 034005. https://doi.org/10.1088/1748-9326/aa5fb0
26. Qian, B., Gregorich, E. G., Gameda, S., Hopkins, D. W., & Wang, X. L. (2011). Observed soil temperature trends associated with climate change in Canada. Journal of Geophysical Research: Atmospheres, 116 (D2), Article D02106. https://doi.org/10.1029/2010JD015012
27. Delacre, M., Lakens, D., & Leys, C. (2017). Why psychologists should by default use Welch’s t-test instead of Student’s t-test. International Review of Social Psychology, 30 (1), 92-101. https://doi.org/10.5334/irsp.82
28. Lakens, D. (2015, January 26). Always use Welch's t-test instead of Student's t-test. The 20% Statistician. http://daniellakens.blogspot.com/2015/01/always-use-welchs-t-test-instead-of.html?m=1
29. Moser, B. K., & Stevens, G. R. (1992). Homogeneity of variance in the two-sample means test. The American Statistician, 46 (1), 19-21. https://doi.org/10.1080/00031305.1992.10475839
30. Li, X., Stringer, L. C., & Dallimer, M. (2021). The spatial and temporal characteristics of urban heat island intensity: Implications for East Africa’s urban development. Climate, 9 (4), Article 51. https://doi.org/10.3390/cli9040051
31. Howell, D. C. (2013). Statistical methods for psychology (8th ed.). ‎Cengage Learning.
32. Stewart, I. D., & Oke, T. R. (2012). Local Climate Zones for urban temperature studies. Bulletin of the American Meteorological Society, 93 (12), 1879-1900. https://doi.org/10.1175/BAMS-D-11-00019.1