Role of Urban Heat Island in local climate change

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Role of Urban Heat Island in local climate change:

Amit Kumar Centre for Environmental Sciences and Technology School of Environment and Earth Sciences Central University of Punjab, Bathinda E-mail: amit.singh@cub.ac.in Role of Urban Heat Island in local climate change 09/01/2014 1

Contents:

Contents Introduction Types of UHI Factors modifying the UHI Methodology for measuring UHI Impacts of UHI Mitigation of UHI Conclusion 09/01/2014 2

Introduction:

Introduction Urban Heat Island (UHI) : I ncreased surface and/or air temperatures observed in an urban environment compared to the rural surroundings. Fig 1: Schematic diagram of UHI (USEPA,2012) Luke Howard was one of the first scientists to observe these temperature differences in 1833 for the city of London ( Oke , 1991). 09/01/2014 3

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09/01/2014 4 Characteristic contributing to heat island formation Effect on the energy balance Lack of vegetation Reduces evaporation Widespread use of impermeable surfaces Reduces evaporation Increased thermal diffusivity of urban materials Increases heat storage Low solar reflectance of urban materials Increases net radiation Urban geometries that trap heat Increases net radiation Urban geometries that slow wind speeds Reduces convection Increased levels of air pollution Increases net radiation Increased energy use Increases anthropogenic heat Table 1: Urban characteristic important to Heat I sland formation ( Gartland , 2011 )

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09/01/2014 5 Table 2: U rban H eat I sland intensity (UHII) of some cities around the world ( Gartland , 2011). City UHII ˚ C Mexico 7.8 New York 8.0 Alaska 2.2 Singapore 4.0 Shanghai 7.4 Beijing 3.3

Types of UHI:

Types of UHI Surface UHI (strong during day time). Atmospheric UHI Canopy layer UHI: Exist in the air of where people live Boundary layer UHI: Start from the rooftop and treetop level and extend up to the point where urban landscapes no longer influence the atmosphere (up to 1 mile). 09/01/2014 6

Factors affecting the Urban Heat Island phenomenon:

Factors affecting the Urban Heat Island phenomenon Population size/density ( Oke , 1973 ) Land/Building Material ( B Offerle , 2006 ) Anthropogenic Heat Sources (cars, air conditioning, industrial processes, power plants, etc.) ( Qihao Weng , 2004 ) UHI intensity decreases with increasing wind speed and cloud cover ( Ackerman, 1985 ) Season 09/01/2014 7

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09/01/2014 8 Fig 2: Different Urban Environment Albedos (USEPA, 2012)

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Source: Morris and Simmonds, 2000. FIG 3: Summer and winter air temperatures in the Central Business District (Urban) and Airport (Rural) of Melbourne, Australia 09/01/2014 9

Methodology for measuring UHI:

Methodology for measuring UHI Fixed Stations Energy balances Mobile traverses Remote sensing Vertical sensing 09/01/2014 10

Fixed Stations:

Fixed Stations Comparing the obtained data from a single pair of urban and rural weather stations. Analysing the data obtained from multiple weather stations to find regional, two-dimensional impacts Analysing a huge set of historical data to examine Urban Heat Island trends over time as a region develops. 09/01/2014 11

Energy balances :

Energy balances Energy balance Equation for UHI Convection + Evaporation + Heat storage = Anthropogenic heat + Net radiation Net Radiation = Incoming solar –Reflected solar + Atmospheric radiation –Surface radiation M easured by albedometer (incoming and reflected solar radiation), radiometer (atmospheric radiation) and pyrgeometre (surface radiation). 09/01/2014 12

Mobile traverses :

Mobile traverses A mobile traverse is carried out on a predetermined path throughout a region, stopping at representative locations to take readings. Drawback: Inability to record simultaneous measurements at different locations. 09/01/2014 13

Remote Sensing :

Remote Sensing Remote sensing can be used to find temperatures by measuring the energy reflected and emitted from them. Power to visualize temperatures over large areas. 09/01/2014 14

Vertical Sensing :

Vertical Sensing These methods include: Sending instrumented balloons aloft, Installing monitoring equipment on radio towers or, Flying at different altitudes in an instrumented helicopter or aero plane. It gives clear cut view of boundary layers. 09/01/2014 15

Impacts of UHI:

Impacts of UHI Differences in Urban- Rural Temperature: Arises due to the interaction of building structure, land cover and land use changes Use of different types of material for urban development ( Oke , 1976; Wang et al., 1990; Arnfield , 2003) . Air Quality (USEPA,2012) Energy Use CO2 Emissions 09/01/2014 16

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Change in rainfall pattern and intensity: Increased level of air pollution may be the cause of reduction in precipitation. Studies reveal that urbanization affects rainfall pattern and rainfall intensity, but how this happens is very poorly understood (Lowry, 1998). Alters humidity, surface wetness and soil moisture level Health Impacts 09/01/2014 17

Mitigation measures:

Mitigation measures Cool roofing materials Cool paving materials Cooling with trees and vegetation 09/01/2014 18

Conclusion:

Conclusion Urban heat island play a major role in urban environment. In Indian context it is a challenging task for environmentalist, policy maker urban development planner due to rapid increase of population and its shifting towards urban areas. 09/01/2014 19

References:

References Ackerman, B., (1985). Temporal march of the Chicago heat island. Journal of Climate and Applied Meteorology, 24(6), 547-554. Arnfield , A. J. (2003). Two decades of urban climate research: a review of turbulence, exchanges of energy and water, and the urban heat island. International Journal of Climatology ,  23 (1), 1-26. Banta, R. M., Senff , C. J., White, A. B., Trainer, M., McNider , R. T., Valente , R. J., ... & Fehsenfeld , F. C. (1998). Daytime buildup and nighttime transport of urban ozone in the boundary layer during a stagnation episode. Journal of Geophysical Research, 103(D17), 22519-22. Bejarán , R. A., & Camilloni , I. A. (2003). Objective method for classifying air masses: an application to the analysis of Buenos Aires’(Argentina) urban heat island intensity.  Theoretical and applied climatology ,  74 (1-2), 93-103. Bornstein, R., & Lin, Q. (2000). Urban heat islands and summertime convective thunderstorms in Atlanta: three case studies.  Atmospheric Environment ,  34 (3), 507-516. Cerveny , R. S., & Balling, R. C. (1998). Weekly cycles of air pollutants, precipitation and tropical cyclones in the coastal NW Atlantic region.  Nature , 394 (6693), 561-563. Chandler, T. J. (1965). Absolute and relative humidities in towns.  Bull. Am. Meteorol . Soc ,  48 , 394-399. Chen, L. X., Li, W. L., Zhu, W. Q., Zhou, X. J., Zhou, Z. J., & Liu, H. L. (2006). Seasonal trends of climate change in the Yangtze Delta and its adjacent regions and their formation mechanisms.  Meteorology and Atmospheric Physics ,  92 (1-2), 11-23. Crutzen , P. J. (2004). New directions: The growing urban heat and pollution “island” effect—Impact on chemistry and climate.  Atmospheric environment , 38 (21), 3539-3540. Deosthali , V. (2000). Impact of rapid urban growth on heat and moisture islands in Pune City, India.  Atmospheric Environment ,  34 (17), 2745-2754. Dixon, P. G., & Mote , T. L. (2003). Patterns and causes of Atlanta's urban heat island-initiated precipitation.  Journal of Applied Meteorology ,  42 (9), 1273-1284. Eliasson , I. (1996). Urban nocturnal temperatures, street geometry and land use.  Atmospheric Environment ,  30 (3), 379-392. 09/01/2014 20

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Figuerola , P. I., & Mazzeo, N. A. (1998). Urban‐rural temperature differences in Buenos Aires.  International Journal of Climatology ,  18 (15), 1709-1723. Gartland , L. (2011).  Heat islands: understanding and mitigating heat in urban areas . Routledge. Ji , C. P., Liu, W. D., & Xuan, C. Y. (2006). Impact of urban growth on the heat island in Beijing.  Diqiu Wuli Xuebao (Chinese Journal of Geophysics) ,  49 (1), 69-77. Kanda , M. (2006). Progress in the scale modeling of urban climate: Review. Theoretical and Applied Climatology ,  84 (1-3), 23-33. Kaufman, Y. J., Tanré , D., & Boucher, O. (2002). A satellite view of aerosols in the climate system.  Nature ,  419 (6903), 215-223. Kidder, S. Q., & Essenwanger, O. M. (1995). The effect of clouds and wind on the difference in nocturnal cooling rates between urban and rural areas.  Journal of Applied Meteorology ,  34 (11), 2440-2448. Unger, J., Sümeghy, Z., & Zoboki, J. (2001). Temperature cross-section features in an urban area.  Atmospheric Research ,  58 (2), 117-127. Voogt , J. A., & Oke , T. R. (2003). Thermal remote sensing of urban climates. Remote sensing of environment ,  86 (3), 370-384. Wang, W. C., Zeng, Z., & Karl, T. R. (1990). Urban heat islands in China. Geophysical Research Letters ,  17 (13), 2377-2380 Lo, C. P., Quattrochi , D. A., & Luvall , J. C. (1997). Application of high-resolution thermal infrared remote sensing and GIS to assess the urban heat island effect. International Journal of Remote Sensing ,  18 (2), 287-304. Lowry, W. P. (1998). Urban effects on precipitation amount.  Progress in Physical Geography ,  22 (4), 477-520. 09/01/2014 21

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09/01/2014 22 Magee, N., Curtis, J., & Wendler , G. (1999). The urban heat island effect at Fairbanks, Alaska.  Theoretical and Applied Climatology ,  64 (1-2), 39-47. Mölders , N., & Olson, M. A. (2004). Impact of urban effects on precipitation in high latitudes.  Journal of hydrometeorology ,  5 (3), 409-429. Morris, C. J. G., Simmonds, I., & Plummer, N. (2001). Quantification of the influences of wind and cloud on the nocturnal urban heat island of a large city. Journal of Applied Meteorology ,  40 (2), 169-182. Oke , T. R. (1973). City size and the urban heat island.  Atmospheric Environment (1967) ,  7 (8), 769-779. Oke , T. R. (1976). The distinction between canopy and boundary‐layer urban heat islands.  Atmosphere ,  14 (4), 268-277. Oke , T. R. (1982). The energetic basis of the urban heat island.  Quarterly Journal of the Royal Meteorological Society ,  108 (455), 1-24. Oke , T. R. (1995). The heat island of the urban boundary layer: characteristics, causes and effects.  NATO ASI Series E Applied Sciences-Advanced Study Institute ,  277 , 81-108. Oke , T. R. (1997). Urban climates and global environmental change.  Applied Climatology: Principles & Practices. New York, NY: Routledge , 273-287. Oke , T. R., & Cleugh , H. A. (1987). Urban heat storage derived as energy balance residuals.  Boundary-Layer Meteorology ,  39 (3), 233-245. Pandey, P., Kumar, D., Prakash, A., Masih, J., Singh, M., Kumar, S., ... & Kumar, K. (2012). A study of urban heat island and its association with particulate matter during winter months over Delhi.  Science of the Total Environment ,  414 , 494-507. Rosenfeld, D. (2000). Suppression of rain and snow by urban and industrial air pollution.  Science ,  287 (5459), 1793-1796 .

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09/01/2014 23 Shahgedanova , M., Burt, T. P., & Davies, T. D. (1997). Some aspects of the three‐dimensional heat island in Moscow.  International journal of climatology , 17 (13), 1451-1465. Shepherd , J. M. (2005). A review of current investigations of urban-induced rainfall and recommendations for the future.  Earth Interactions ,  9 (12), 1-27. Shepherd, J. M., Pierce, H., & Negri , A. J. (2002). Rainfall modification by major urban areas: Observations from spaceborne rain radar on the TRMM satellite. Journal of Applied Meteorology ,  41 (7), 689-701. Souch , C., & Grimmond , S. (2006). Applied climatology: urban climate. Progress in Physical Geography ,  30 (2), 270. Sundborg , Å. (1951).  Climatological Studies in Uppsala: With Special Regard to the Temperature Conditions in the Urban Area . Appelbergs Boktryckeriaktiebolag . Tereshchenko, I. E., & Filonov, A. E. (2001). Air temperature fluctuations in Guadalajara, Mexico, from 1926 to 1994 in relation to urban growth. International Journal of Climatology ,  21 (4), 483-494. Thielen , J., Wobrock , W., Gadian , A., Mestayer , P. G., & Creutin , J. D. (2000). The possible influence of urban surfaces on rainfall development: a sensitivity study in 2D in the meso -γ-scale.  Atmospheric Research ,  54 (1), 15-39.

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09/01/2014 24 Thank You

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