Simulating the Urban Heat Island Augmented with a Heat Wave Episode Using ICTP RegCM4.7 in a Mega-Urban Structure of Karachi, Pakistan

Document Type : Regular Article

Authors

1 Computational Meteorologist, Numerical Weather Prediction Center, Pakistan Meteorological Department, Islamabad, Pakistan

2 Senior Scientist, Earth System Physics, The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy

3 Global Change Impact Studies Centre (GCISC), Ministry of Climate Change, Pakistan

4 Senior Meteorologist, Numerical Weather Prediction Center, Pakistan Meteorological Department, Islamabad, Pakistan

5 Post Doc Researcher, CEN, Institute of Geography, University of Hamburg, Hamburg, Germany

6 Electronic Engineer, Numerical Weather Prediction Center, Pakistan Meteorological Department, Islamabad, Pakistan

Abstract

The metropolis of Karachi, with a density of around 4000 persons/km2 at present, is going through unprecedented urbanization and population growth, which can augment Urban Heat Island (UHI) triggered heat wave impacts on life and living. Here, we investigate skill of Regional Climate Model version 4.7 (RegCM4.7) in simulating 2015 heat wave episode in southern Pakistan by dynamically downscaling ERA-Interim reanalysis at 10km resolution and switching on the urban parameterization in the employed land surface scheme. Our results suggest that the RegCM4.7 has successfully reproduced the overall conditions of the 2015 heat wave. For instance simulated surface temperature maxima is seen well above 50°C for at least three consecutive days along the austere heat wave duration. Also, extended sustenance of a ridge in locality of the Karachi, as well as a low pressure system in adjacent Arabian Sea is seen to restrain normal drift of sea-breeze to the coastal city, in the simulated output. The National Weather Service (NWS) based heat index derived from the simulation is seen to remain well above 124°F during the whole heat wave period, placing the city in an “Extreme Danger” class of discomfort and high vulnerability to heat stroke. The UHI integrated RegCM4.7 is hence recommended for use in modelling to help in adaptation strategies against occurrences of such heat wave events in future.

Highlights

Google Scholar | Scopus PlumX Metrics | Mendeley

Keywords

Main Subjects


[1]     Yasmeen Z, Afzaal. M, Anjum. MA, A. B. Urban heat island in changing climate (A case study of Karachi heat wave, 2015). World Environment Day. Pakistan Engineering Congress. 2017.
[2]     Huszar P, Belda M, Halenka T. On the long-term impact of emissions from central European cities on regional air quality. Atmos Chem Phys 2016;16:1331–52. doi:10.5194/acp-16-1331-2016.
[3]     Huszár P, Belda M, Karlický J, Pišoft P, Halenka T. The regional impact of urban emissions on climate over central Europe: present and future emission perspectives. Atmos Chem Phys 2016;16:12993–3013. doi:10.5194/acp-16-12993-2016.
[4]     Folberth GA, Butler TM, Collins WJ, Rumbold ST. Megacities and climate change–A brief overview. Environ Pollut 2015;203:235–42.
[5]     Roth M. Review of atmospheric turbulence over cities. Q J R Meteorol Soc 2007;126:941–90. doi:10.1002/qj.49712656409.
[6]     Kastner-Klein P, Fedorovich E, Rotach MW. A wind tunnel study of organised and turbulent air motions in urban street canyons. J Wind Eng Ind Aerodyn 2001;89:849–61. doi:10.1016/S0167-6105(01)00074-5.
[7]     Hou A, Ni G, Yang H, Lei Z. Numerical Analysis on the Contribution of Urbanization to Wind Stilling: An Example over the Greater Beijing Metropolitan Area. J Appl Meteorol Climatol 2013;52:1105–15. doi:10.1175/JAMC-D-12-013.1.
[8]     Lee S-H, Kim S-W, Angevine WM, Bianco L, McKeen SA, Senff CJ, et al. Evaluation of urban surface parameterizations in the WRF model using measurements during the Texas Air Quality Study 2006 field campaign. Atmos Chem Phys 2011;11:2127–43. doi:10.5194/acp-11-2127-2011.
[9]     Huszar P, Halenka T, Belda M, Zak M, Sindelarova K, Miksovsky J. Regional climate model assessment of the urban land-surface forcing over central Europe 2014.
[10]    Theeuwes NE, Steeneveld G-J, Ronda RJ, Rotach MW, Holtslag AAM. Cool city mornings by urban heat. Environ Res Lett 2015;10:114022.
[11]    Angevine WM, White AB, Senff CJ, Trainer M, Banta RM, Ayoub MA. Urban-rural contrasts in mixing height and cloudiness over Nashville in 1999. J Geophys Res Atmos 2003;108:n/a-n/a. doi:10.1029/2001JD001061.
[12]    Meehl GA. More Intense, More Frequent, and Longer Lasting Heat Waves in the 21st Century. Science (80- ) 2004;305:994–7. doi:10.1126/science.1098704.
[13]    Chen F, Kusaka H, Bornstein R, Ching J, Grimmond CSB, Grossman-Clarke S, et al. The integrated WRF/urban modelling system: development, evaluation, and applications to urban environmental problems. Int J Climatol 2011;31:273–88. doi:10.1002/joc.2158.
[14]    Liao J, Wang T, Wang X, Xie M, Jiang Z, Huang X, et al. Impacts of different urban canopy schemes in WRF/Chem on regional climate and air quality in Yangtze River Delta, China. Atmos Res 2014;145–146:226–43. doi:10.1016/j.atmosres.2014.04.005.
[15]    Sajjad SH, Hussain B, Ahmed Khan M, Raza A, Zaman B, Ahmed I. On rising temperature trends of Karachi in Pakistan. Clim Change 2009;96:539–47. doi:10.1007/s10584-009-9598-y.
[16]    Qureshi S. The fast growing megacity Karachi as a frontier of environmental challenges: Urbanization and contemporary urbanism issues. J Geogr Reg Plan 2010;3:306–21.
[17]    Anwar F. Karachi city climate change-adaptation strategy a roadmap. J Res Archit Plan 2012;11.
[18]    Sajjad SH, Blond N, Batool R, Shirazi SA, Shakrullah K, Bhalli MN. Study of urban heat island of Karachi by using finite volume mesoscale model. J Basic Appl Sci 2015;11:101–5.
[19]    Zahid M, Rasul G. Changing trends of thermal extremes in Pakistan. Clim Change 2012;113:883–96. doi:10.1007/s10584-011-0390-4.
[20]    Saeed F, Suleri AQ. Future heat waves in Pakistan under IPCC’s climate change scenario. Sustain Dev Policy Inst Policy Br 2015;46.
[21]    Cheema AR. High-rise buildings worsened heatwave. Nature 2015;524:35.
[22]    Chaudhry QZ, Rasul G, Kamal A, Mangrio MA, Mahmood S. Technical report on Karachi heat wave June 2015. Islam Gov Pakistan Minist Clim Chang 2015.
[23]    Giorgi F, Coppola E, Solmon F, Mariotti L, Sylla MB, Bi X, et al. RegCM4: model description and preliminary tests over multiple CORDEX domains. Clim Res 2012;52:7–29.
[24]    Lawrence DM, Oleson KW, Flanner MG, Thornton PE, Swenson SC, Lawrence PJ, et al. Parameterization improvements and functional and structural advances in Version 4 of the Community Land Model. J Adv Model Earth Syst 2011;3:n/a-n/a. doi:10.1029/2011MS00045.
[25]    Oleson KW, Lawrence DM, Gordon B, Flanner MG, Kluzek E, Peter J, et al. Technical description of version 4.0 of the Community Land Model (CLM) 2010.
[26]    Oleson KW, Bonan GB, Feddema J, Vertenstein M, Grimmond CSB. An Urban Parameterization for a Global Climate Model. Part I: Formulation and Evaluation for Two Cities. J Appl Meteorol Climatol 2008;47:1038–60. doi:10.1175/2007JAMC1597.1.
[27]    Kusaka H, Kondo H, Kikegawa Y, Kimura F. A Simple Single-Layer Urban Canopy Model For Atmospheric Models: Comparison With Multi-Layer And Slab Models. Boundary-Layer Meteorol 2001;101:329–58. doi:10.1023/A:1019207923078.
[28]    KUSAKA H, KIMURA F. Coupling a Single-Layer Urban Canopy Model with a Simple Atmospheric Model: Impact on Urban Heat Island Simulation for an Idealized Case. J Meteorol Soc Japan 2004;82:67–80. doi:10.2151/jmsj.82.67.
[29]    Jackson TL, Feddema JJ, Oleson KW, Bonan GB, Bauer JT. Parameterization of Urban Characteristics for Global Climate Modeling. Ann Assoc Am Geogr 2010;100:848–65. doi:10.1080/00045608.2010.497328.
[30]    Dee DP, Uppala SM, Simmons AJ, Berrisford P, Poli P, Kobayashi S, et al. The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q J R Meteorol Soc 2011;137:553–97. doi:10.1002/qj.828.
[31]    Lorenz R, Jaeger EB, Seneviratne SI. Persistence of heat waves and its link to soil moisture memory. Geophys Res Lett 2010;37:n/a-n/a. doi:10.1029/2010GL042764.
[32]    Miralles DG, Teuling AJ, van Heerwaarden CC, Vilà-Guerau de Arellano J. Mega-heatwave temperatures due to combined soil desiccation and atmospheric heat accumulation. Nat Geosci 2014;7:345–9. doi:10.1038/ngeo2141.
[33]    Wang P, Zhang Q, Yang Y, Tang J. The Sensitivity to Initial Soil Moisture for Three Severe Cases of Heat Waves Over Eastern China. Front Environ Sci 2019;7. doi:10.3389/fenvs.2019.00018.
[34]    Hanif U. Socio-Economic Impacts of Heat Wave in Sindh. Pakistan J Meteorol Vol 2017;13.