Interactions between urban heat islands and heat waves
Heat waves (HWs) are among the most damaging climate extremes to human society. Climate models consistently project that HW frequency, severity, and duration will increase markedly over this century. For urban residents, the urban heat island (UHI) effect further exacerbates the heat stress resultin...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2018-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/aa9f73 |
| _version_ | 1797748116061945856 |
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| author | Lei Zhao Michael Oppenheimer Qing Zhu Jane W Baldwin Kristie L Ebi Elie Bou-Zeid Kaiyu Guan Xu Liu |
| author_facet | Lei Zhao Michael Oppenheimer Qing Zhu Jane W Baldwin Kristie L Ebi Elie Bou-Zeid Kaiyu Guan Xu Liu |
| author_sort | Lei Zhao |
| collection | DOAJ |
| description | Heat waves (HWs) are among the most damaging climate extremes to human society. Climate models consistently project that HW frequency, severity, and duration will increase markedly over this century. For urban residents, the urban heat island (UHI) effect further exacerbates the heat stress resulting from HWs. Here we use a climate model to investigate the interactions between the UHI and HWs in 50 cities in the United States under current climate and future warming scenarios. We examine UHI _2m (defined as urban-rural difference in 2m-height air temperature) and UHI _s (defined as urban-rural difference in radiative surface temperature). Our results show significant sensitivity of the interaction between UHI and HWs to local background climate and warming scenarios. Sensitivity also differs between daytime and nighttime. During daytime, cities in the temperate climate region show significant synergistic effects between UHI and HWs in current climate, with an average of 0.4 K higher UHI _2m or 2.8 K higher UHI _s during HWs than during normal days. These synergistic effects, however, diminish in future warmer climates. In contrast, the daytime synergistic effects for cities in dry regions are insignificant in the current climate, but emerge in future climates. At night, the synergistic effects are similar across climate regions in the current climate, and are stronger in future climate scenarios. We use a biophysical factorization method to disentangle the mechanisms behind the interactions between UHI and HWs that explain the spatial-temporal patterns of the interactions. Results show that the difference in the increase of urban versus rural evaporation and enhanced anthropogenic heat emissions (air conditioning energy use) during HWs are key contributors to the synergistic effects during daytime. The contrast in water availability between urban and rural land plays an important role in determining the contribution of evaporation. At night, the enhanced release of stored and anthropogenic heat during HWs are the primary contributors to the synergistic effects. |
| first_indexed | 2024-03-12T16:00:24Z |
| format | Article |
| id | doaj.art-346037c7cc8c46ef99fdede0782679ec |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:00:24Z |
| publishDate | 2018-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-346037c7cc8c46ef99fdede0782679ec2023-08-09T14:38:34ZengIOP PublishingEnvironmental Research Letters1748-93262018-01-0113303400310.1088/1748-9326/aa9f73Interactions between urban heat islands and heat wavesLei Zhao0https://orcid.org/0000-0002-6481-3786Michael Oppenheimer1Qing Zhu2Jane W Baldwin3Kristie L Ebi4https://orcid.org/0000-0003-4746-8236Elie Bou-Zeid5Kaiyu Guan6https://orcid.org/0000-0002-3499-6382Xu Liu7Program in Science , Technology and Environmental Policy (STEP), Princeton University, Princeton, NJ, United States of America; Author to whom any correspondence should be addressed.Woodrow Wilson School of Public and International Affairs and Department of Geosciences , Princeton University, Princeton, NJ, United States of AmericaClimate and Ecosystem Sciences Division, Climate Sciences Department, Lawrence Berkeley National Laboratory , Berkeley, CA, United States of AmericaProgram in Atmospheric and Oceanic Sciences (AOS) , Princeton University, Princeton, NJ, United States of AmericaDepartment of Global Health , University of Washington, Seattle, WA, United States of AmericaDepartment of Civil and Environmental Engineering , Princeton University, Princeton, NJ, United States of AmericaDepartment of Natural Resources and Environmental Sciences and National Center for Supercomputing Applications , University of Illinois at Urbana-Champaign, Champaign, IL, United States of AmericaChina Energy Group, International Energy Analysis Department, Lawrence Berkeley National Laboratory , Berkeley, CA, United States of AmericaHeat waves (HWs) are among the most damaging climate extremes to human society. Climate models consistently project that HW frequency, severity, and duration will increase markedly over this century. For urban residents, the urban heat island (UHI) effect further exacerbates the heat stress resulting from HWs. Here we use a climate model to investigate the interactions between the UHI and HWs in 50 cities in the United States under current climate and future warming scenarios. We examine UHI _2m (defined as urban-rural difference in 2m-height air temperature) and UHI _s (defined as urban-rural difference in radiative surface temperature). Our results show significant sensitivity of the interaction between UHI and HWs to local background climate and warming scenarios. Sensitivity also differs between daytime and nighttime. During daytime, cities in the temperate climate region show significant synergistic effects between UHI and HWs in current climate, with an average of 0.4 K higher UHI _2m or 2.8 K higher UHI _s during HWs than during normal days. These synergistic effects, however, diminish in future warmer climates. In contrast, the daytime synergistic effects for cities in dry regions are insignificant in the current climate, but emerge in future climates. At night, the synergistic effects are similar across climate regions in the current climate, and are stronger in future climate scenarios. We use a biophysical factorization method to disentangle the mechanisms behind the interactions between UHI and HWs that explain the spatial-temporal patterns of the interactions. Results show that the difference in the increase of urban versus rural evaporation and enhanced anthropogenic heat emissions (air conditioning energy use) during HWs are key contributors to the synergistic effects during daytime. The contrast in water availability between urban and rural land plays an important role in determining the contribution of evaporation. At night, the enhanced release of stored and anthropogenic heat during HWs are the primary contributors to the synergistic effects.https://doi.org/10.1088/1748-9326/aa9f73heat waveurban heat islandsurface evaporationsurface biophysical processesclimate change |
| spellingShingle | Lei Zhao Michael Oppenheimer Qing Zhu Jane W Baldwin Kristie L Ebi Elie Bou-Zeid Kaiyu Guan Xu Liu Interactions between urban heat islands and heat waves Environmental Research Letters heat wave urban heat island surface evaporation surface biophysical processes climate change |
| title | Interactions between urban heat islands and heat waves |
| title_full | Interactions between urban heat islands and heat waves |
| title_fullStr | Interactions between urban heat islands and heat waves |
| title_full_unstemmed | Interactions between urban heat islands and heat waves |
| title_short | Interactions between urban heat islands and heat waves |
| title_sort | interactions between urban heat islands and heat waves |
| topic | heat wave urban heat island surface evaporation surface biophysical processes climate change |
| url | https://doi.org/10.1088/1748-9326/aa9f73 |
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