Enhanced nighttime heatwaves over African urban clusters
Despite the threat that nighttime heatwave poses to public health and the environment in the developing world, it remains relatively understudied in Africa, especially in its rapidly expanding urban areas with large populations. Using meteorological observations, climate reanalysis, remote sensing d...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2022-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/aca920 |
| _version_ | 1797747169198866432 |
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| author | Eghosa Igun Xiyan Xu Zitong Shi Gensuo Jia |
| author_facet | Eghosa Igun Xiyan Xu Zitong Shi Gensuo Jia |
| author_sort | Eghosa Igun |
| collection | DOAJ |
| description | Despite the threat that nighttime heatwave poses to public health and the environment in the developing world, it remains relatively understudied in Africa, especially in its rapidly expanding urban areas with large populations. Using meteorological observations, climate reanalysis, remote sensing datasets, and integrated methodology, we found that during 1981–2020, nighttime heatwaves dramatically increased with early onset dates over Africa. Large scale circulation induced dry conditions over land which explains the major heatwaves across all climate zones. Meanwhile, the increasing trend of nighttime heatwaves in urban areas than rural areas in both tropical and temperate climates is largely due to urbanization, which amplifies heatwaves with urban heat island (UHI) effects. The strongest contribution of urbanization to nighttime heatwaves was observed in temperate climate, leading to a 46% increase in the heatwave duration. In arid climate, urban expansion has a negative impact on nighttime heatwaves, due to the cool island effect of urban greens and weak urbanization. The major contribution of urbanization to the urban-rural contrast of nighttime heatwave trends in temperate climate can be attributed to stronger UHI intensity resulting from lower windspeed and less evapotranspiration. Without appropriate adaptation efforts to reduce heatwave exposure, the risks posed in Africa’s urban areas will continue to increase under future warming. |
| first_indexed | 2024-03-12T15:48:12Z |
| format | Article |
| id | doaj.art-b2da9d64322e4fcc90e719b653fec4a2 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:48:12Z |
| publishDate | 2022-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-b2da9d64322e4fcc90e719b653fec4a22023-08-09T15:21:12ZengIOP PublishingEnvironmental Research Letters1748-93262022-01-0118101400110.1088/1748-9326/aca920Enhanced nighttime heatwaves over African urban clustersEghosa Igun0https://orcid.org/0000-0003-1749-7001Xiyan Xu1https://orcid.org/0000-0003-2732-1325Zitong Shi2Gensuo Jia3https://orcid.org/0000-0001-5950-9555Key Laboratory of Regional Climate-Environment for East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences , Beijing 100029, People’s Republic of China; University of Chinese Academy of Sciences , Beijing, People’s Republic of ChinaKey Laboratory of Regional Climate-Environment for East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences , Beijing 100029, People’s Republic of ChinaNational Institute of Natural Hazards, China Ministry of Emergency Management , Beijing, People’s Republic of ChinaKey Laboratory of Regional Climate-Environment for East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences , Beijing 100029, People’s Republic of China; University of Chinese Academy of Sciences , Beijing, People’s Republic of ChinaDespite the threat that nighttime heatwave poses to public health and the environment in the developing world, it remains relatively understudied in Africa, especially in its rapidly expanding urban areas with large populations. Using meteorological observations, climate reanalysis, remote sensing datasets, and integrated methodology, we found that during 1981–2020, nighttime heatwaves dramatically increased with early onset dates over Africa. Large scale circulation induced dry conditions over land which explains the major heatwaves across all climate zones. Meanwhile, the increasing trend of nighttime heatwaves in urban areas than rural areas in both tropical and temperate climates is largely due to urbanization, which amplifies heatwaves with urban heat island (UHI) effects. The strongest contribution of urbanization to nighttime heatwaves was observed in temperate climate, leading to a 46% increase in the heatwave duration. In arid climate, urban expansion has a negative impact on nighttime heatwaves, due to the cool island effect of urban greens and weak urbanization. The major contribution of urbanization to the urban-rural contrast of nighttime heatwave trends in temperate climate can be attributed to stronger UHI intensity resulting from lower windspeed and less evapotranspiration. Without appropriate adaptation efforts to reduce heatwave exposure, the risks posed in Africa’s urban areas will continue to increase under future warming.https://doi.org/10.1088/1748-9326/aca920Africanighttime heatwavesurban heat islandurbanization |
| spellingShingle | Eghosa Igun Xiyan Xu Zitong Shi Gensuo Jia Enhanced nighttime heatwaves over African urban clusters Environmental Research Letters Africa nighttime heatwaves urban heat island urbanization |
| title | Enhanced nighttime heatwaves over African urban clusters |
| title_full | Enhanced nighttime heatwaves over African urban clusters |
| title_fullStr | Enhanced nighttime heatwaves over African urban clusters |
| title_full_unstemmed | Enhanced nighttime heatwaves over African urban clusters |
| title_short | Enhanced nighttime heatwaves over African urban clusters |
| title_sort | enhanced nighttime heatwaves over african urban clusters |
| topic | Africa nighttime heatwaves urban heat island urbanization |
| url | https://doi.org/10.1088/1748-9326/aca920 |
| work_keys_str_mv | AT eghosaigun enhancednighttimeheatwavesoverafricanurbanclusters AT xiyanxu enhancednighttimeheatwavesoverafricanurbanclusters AT zitongshi enhancednighttimeheatwavesoverafricanurbanclusters AT gensuojia enhancednighttimeheatwavesoverafricanurbanclusters |