American Journal of Environment and Sustainable Development
Articles Information
American Journal of Environment and Sustainable Development, Vol.4, No.2, Jun. 2019, Pub. Date: May 30, 2019
Boundary Layer Turbulence and Urban Heat Variability in the Coastal City of Port Harcourt, Nigeria
Pages: 77-83 Views: 144 Downloads: 62
Authors
[01] David Edokpa, Department of Geography and Environmental Management, Rivers State University, Port Harcourt, Nigeria.
[02] Peace Nwaerema, Department of Geography and Environmental Management, University of Port Harcourt, Port Harcourt, Nigeria.
Abstract
This study examined the boundary layer turbulence pattern and the heat index in the lower atmosphere of the coastal city of Port Harcourt using Richardson number (Ri) technique and temperature-humidity index equation. Six years surface data (2011-2016) from Era-Interim Platform were used for this study. The study was conducted for the period of October-December 2016 when the black soot emission from illegal petroleum crude refining was noticed across the atmospheric boundary layer of Port Harcourt. Mean turbulence within the surface layer (10-50m) height was between 0.27-0.52. This indicates a weak mechanical turbulence since all the values were greater than the Richardson critical (Ric) value of 0.25. Generally, Ri values for the study area at the surface layer were less than 1 while Ri values at the mid layer (50-100m) were greater than 1 indicating laminar condition. The heat index analysis shows that the extreme caution and danger levels constituted about 85% which could generate heat stroke for the city dwellers especially the elderly persons. Study results revealed that the heat island during the night is enhanced within the hours 00:00-03:00 hours. The weak Ri values of mechanical origin shows that the enhanced heat island mostly experienced during the night periods will not be diluted easily and faster. This enhanced heat island is due to the positive radiation forcing of the emitted black soot, the humid atmosphere as well as the very stable atmospheric condition of Port Harcourt. These lower atmospheric factors reduce the strength of the winds in modifying the heat island. In order to mitigate the increased heat island in the city mostly at night, policy makers should ensure that anthropogenic emission releases are reduced from sources to avoid air pollutants build-up. Also, the greater Port Harcourt plan that proposes the decongestion of the city’s increasing population should be adopted to create opportunity for adequate expansion thereby reducing concentration of business hubs around the long-standing city center.
Keywords
Turbulence, Heat Index, Port Harcourt, Black Soot, Richardson Number, Atmosphere
References
[01] Zhong S, Qian Y, Zhoa C, Leung R, Wang H, Yang B, Fan J, Yan H, Yang X-Q, Liu D (2017). Urbanization-induced urban heat island and aerosols effects in climate extremes in Yangtze River Delta region of China. Atmos. Chem. Phys. 17: 5439-5457.
[02] Soltani A, Sharifi E (2017). Daily variation of urban heat island effect and its correlations to urban greenery: A case study of Adelaide. Frontiers of Architectural Research. 6 (4): 529-538.
[03] Nwaerema P, Edokpa DO (2019). Regional Assessment of Population and Warming of a Tropical Country, Nigeria, from 2006 to 2036. Environmental and Earth Science Research Journal. 6 (1): 1-7.
[04] Nwaerema P, Edokpa DO (2018). Population Variability and Heat Bias Prediction in a Tropical Country, Nigeria, from 2006 to 2036. Advance Journal of Social Science. 4 (1): 28-38.
[05] Mohajerani A, Bakaric J, Jeffery-Bailey T (2017). The urban heat island effect, it causes, and mitigation, with reference to the thermal properties of asphalt concrete. Journal of Environmental Management. 197: 522-538.
[06] Environmental Management & Policy Research Institute (2017). Urban Planning Characteristics to Mitigate Climate Change in Context of Urban Heat Island Effect. Final Report. The Energy and Resource Institute, Bangalore. 82pp.
[07] Edokpa DO (2018). Atmospheric Stability Conditions of the Lower Atmosphere in Selected Cities in Nigeria. An Unpublished Ph.D. Thesis, Department of Geography and Environmental Management, University of Port Harcourt.
[08] Fallmann J, Forkel R, Emeis S (2016). Secondary effects of urban heat island mitigation measures on air quality. Atmospheric Environment. 125: 199-211.
[09] Ede PN, Edokpa OD (2017). Satellite determination of particulate load over Port Harcourt during black soot incidents. Journal of Atmospheric Pollution. 5 (2): 55-61.
[10] Atiku FA, Mitchell EJS, Lea-Langton AR, Jones JM, Williams A, Bartle KD (2016). The Impact of Fuel Properties on the Composition of Soot Produced by the Combustion of Residential Solid Fuels in a Domestic Stove. Fuel Processing Technology. 151: 117-125.
[11] Andreae MO, Gelencser A (2006). Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols, Atmos. Chem. Phys. 6: 3131–3148.
[12] Edokpa OD, Nwagbara MO (2017). Atmospheric stability pattern over Port Harcourt, Nigeria. Journal of Atmospheric Pollution. 5 (1): 7-19.
[13] Encyclopaedia Britannica (2016). Richardson Number. Available from: www.britannica.com/science/Richardson-number.
[14] Zilitinkevich S, Baklanov A (2002). Calculation of the height of stable boundary layers in practical applications. Boundary-Layer Meteorology. 105: 389-409.
[15] National Weather Service (2014). The Heat Index Equation. National Centers for Environmental Prediction, Weather Prediction Center, 5830 University Research Court, College Park, Maryland 20740.
[16] Pielke RASr (2002). Mesoscale Meteorological Modelling. 2nd Edition, Academic Press.
[17] Galperin B, Sukoriansky S, Anderson PS (2007). On the critical Richardson number in stably stratified turbulence. Amos. Sc. Let. 8: 65-69.
[18] Stull RB (1988). An Introduction to Boundary Layer Meteorology. Netherland: Springer.
[19] Jacobson MZ (1999). Fundamentals of Atmospheric Modelling. Cambridge: University Press.
[20] Arya SPS (1988). Introduction to Micrometeorology. New York: Academic Press.
[21] Lee TW, Choi HS, Lee J (2014). Generalized Scaling of Urban Heat Island Effects and its Application for Energy Consumption and Renewable Energy. Advances in Meteorology, 2014: 1-5.
[22] Ramamurthy P, Bou-Zeid E (2017). Heatwaves and urban heat island. A comparative analysis of multiple cities. Journal of Geophysical Research: Atmospheres, 122: 168-178.
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