The Influence of Local Rainy and Dry Seasons on the Diurnal Temperature Range in Nigeria
- 1 Institute of Natural Resources, Environment and Sustainable Development, University of Port Harcourt, Port Harcourt, Nigeria
- 2 Institute of Natural Resources, Environment and Sustainable Development, University of Port Harcourt, Port Harcourt, Nigeria
Abstract
This study analyzed the impact of the local dry and rainy seasons on diurnal temperature range (DTR), for each major climatic zone of Nigeria namely the tropical monsoon, tropical savannah and semi-arid, using meteorological data from thirteen observation stations for the period 1981 to 2021. DTR was computed from the difference of minimum temperature from maximum temperature and yearly and forty one years’ monthly averages of DTR and rainfall were computed and plotted in different graphs. The overall results from each climatic zone showed that DTR fluctuates with the seasons and there is an inverse relationship between DTR and rainfall whereby the value of DTR decreases as the rainy season approaches but increases as the rainy season departs ushering in the dry season or conversely DTR increases as the dry season approaches and decreases as the dry season departs ushering-in the rainy season. Secondly, the average yearly patterns of rainfall and DTR are roughly and oppositely shaped parabolas where the peak value of rainfall is diametrically opposite to the trough value of DTR and the least or nil volume of rainfall corresponds to the highest value of DTR. Thirdly, due to the yearly seasonal cycle of dry and rainy seasons in Nigeria coupled with the inverse relationship between DTR and Rainfall, the seasonal plot of DTR and rainfall is also cyclic in pattern with DTR cycle lagging 180 degrees with the rainfall cycle and the intersection of the two cycles represents the departure of one season and onset of another season while each half-cycle represents either the dry or rainy season. Fourthly, the dependence of DTR on any season at hand in Nigeria makes DTR season-forcing. This fourth result is underpinned by a result that showed that the 1981 and 2021 patterns of DTR and 1981 and 2021 patterns of rainfall when compared were similar, the differences were in the volume of rainfall which was due to climate change that has taken place over the four decades and which also impacted DTR since DTR varies inversely with rainfall. Finally and notwithstanding the common grounds of the results stated above, the result further showed that each climatic zone of Nigeria reacts differently to the local and global climate changes leading to the magnitude of DTR and the volume of rainfall being different across climatic zones, with rainfall volume and duration decreasing towards the arid North from the Coastal South while contrariwise DTR increases towards the arid North from the Coastal South.
- Britannica (2023) Temperature. https://www.britannica.com/science/climate-meteorology/Temperature#ref149502
- Yang, J., Liu, H.-Z., Ou, C.-Q., Lin, G.-Z., Zhou, Q., Shen, G.-C., Chen, P.-Y. and Guo, Y. (2013) Global Climate Change: Impact of Diurnal Temperature Range on Mortality in Guangzhou, China. Environmental Pollution, 175, 131-136. https://doi.org/10.1016/j.envpol.2012.12.021
- Ding, Z., Guo, P., Xie, F., Chu, H., Li, K., Pu, J., Pang, S., Dong, H., Liu, Y., Pi, F. and Zhang, Q.Y. (2015) Impact of Diurnal Temperature Range on Mortality in a High Plateau Area in Southwest China: A Time Series Analysis. Science of The Total Environment, 526, 358-365. https://doi.org/10.1016/j.scitotenv.2015.05.012
- Karl, T.R., Jones, P.D., Knight, R.W., Kukla, G., Neil, P., Vyacheslav, R., Gallo, K.P., Lindseay, J., Charlson, R.J. and Peterson, T.C. (1993) Asymmetric Patterns of Daily Maximum and Minimum Temperature. Papers in Natural Resources, 185, 1007-1023. https://digitalcommons.unl.edu/natrespapers/185
- Karl, T.R., Kukla, G. and Gavin, J. (1987) Recent Temperature Changes during Overcast and Clear Skies on the United States. Journal of Applied Meteorology and Climatology, 26, 698-711. https://doi.org/10.1175/1520-0450(1987)026 2.0.CO;2
- Dai, A., Trenberth, K.E. and Karl, T.R. (1999) Effects of Clouds, Soil Moisture, Precipitation and Water Vapor on Diurnal Temperature Range. Journal of Climate, 12, 2451-2473. https://doi.org/10.1175/1520-0442(1999)012 2.0.CO;2
- Zhou, L., Dai, A., Dai, Y., Vose, R.S., Zou, C.Z., Tian, Y. and Chen, H. (2009) Spatial Dependence of Diurnal Temperature Range Trends on Precipitation from 1950 to 2004. Climate Dynamics, 32, 429-440 https://doi.org/10.1007/s00382-008-0387-5
- WW2010 (2010) Effect of Cloud Cover on Forecasted Temperatures. Department of Atmospheric Sciences (DAS), University of Illinois, Urbana-Champaign. http://ww2010.atmos.uiuc.edu/(Gh)/wwhlpr/fcst_temps_cloud_cover.rxml
- Seman, S. (2020) METEO 3: Introductory Meteorology. Pennsylvania State University, State College.
- Wang, K., Ye, H., Chen, F., Xiong, Y. and Wang, C. (2012) Urbanization Effect on the Diurnal Temperature Range: Different Roles under Solar Dimming and Brightening. Journal of Climate, 25, 1022-1027. https://doi.org/10.1175/JCLI-D-10-05030.1
- Zhou, L., Dickinson, R.E., Tian, Y., Fang, J., Li, Q., Kaufmann, R.K., Tucker, C.J. and Myneni, R.B. (2004) Evidence for a Significant Urbanization Effect on Climate in China. Proceedings of the National Academy of Sciences of the United States of America, 101, 9540-9544. https://doi.org/10.1073/pnas.0400357101