Daytime cooling efficiencies of urban trees derived from land surface temperature are much higher than those for air temperature
Accurately capturing the impact of urban trees on temperature can help optimize urban heat mitigation strategies. Recently, there has been widespread use of remotely sensed land surface temperature ( T _s ) to quantify the cooling efficiency (CE) of urban trees. However, remotely sensed T _s reflect...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ad30a3 |
| _version_ | 1797248725239726080 |
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| author | Meng Du Niantan Li Ting Hu Qiquan Yang TC Chakraborty Zander Venter Rui Yao |
| author_facet | Meng Du Niantan Li Ting Hu Qiquan Yang TC Chakraborty Zander Venter Rui Yao |
| author_sort | Meng Du |
| collection | DOAJ |
| description | Accurately capturing the impact of urban trees on temperature can help optimize urban heat mitigation strategies. Recently, there has been widespread use of remotely sensed land surface temperature ( T _s ) to quantify the cooling efficiency (CE) of urban trees. However, remotely sensed T _s reflects emitted radiation from the surface of an object seen from the point of view of the thermal sensor, which is not a good proxy for the air temperature ( T _a ) perceived by humans. The extent to which the CEs derived from T _s reflect the true experiences of urban residents is debatable. Therefore, this study systematically compared the T _s -based CE (CE _T _s ) with the T _a -based CE (CE _T _a ) in 392 European urban clusters. CE _T _s and CE _T _a were defined as the reductions in T _s and T _a , respectively, for every 1% increase in fractional tree cover (FTC). The results show that the increase in FTC has a substantial impact on reducing T _s and T _a in most cities during daytime. However, at night, the response of T _s and T _a to increased FTC appears to be much weaker and ambiguous. On average, for European cities, daytime CE _T _s reaches 0.075 °C % ^−1 , which is significantly higher (by an order of magnitude) than the corresponding CE _T _a of 0.006 °C % ^−1 . In contrast, the average nighttime CE _T _s and CE _T _a for European cities are similar, both approximating zero. Overall, urban trees can lower daytime temperatures, but the magnitude of their cooling effect is notably amplified when using remotely sensed T _s estimates compared to in situ T _a measurements, which is important to consider for accurately constraining public health benefits. Our findings provide critical insights into the realistic efficiencies of alleviating urban heat through tree planting. |
| first_indexed | 2024-04-24T20:19:09Z |
| format | Article |
| id | doaj.art-1397870d123b4efd9220705db4cc0e80 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-04-24T20:19:09Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-1397870d123b4efd9220705db4cc0e802024-03-22T09:49:05ZengIOP PublishingEnvironmental Research Letters1748-93262024-01-0119404403710.1088/1748-9326/ad30a3Daytime cooling efficiencies of urban trees derived from land surface temperature are much higher than those for air temperatureMeng Du0Niantan Li1Ting Hu2Qiquan Yang3https://orcid.org/0000-0003-1152-5999TC Chakraborty4Zander Venter5https://orcid.org/0000-0003-2638-7162Rui Yao6School of Remote Sensing and Geomatics Engineering, Nanjing University of Information Science and Technology , Nanjing 210044, People’s Republic of ChinaSchool of Remote Sensing and Geomatics Engineering, Nanjing University of Information Science and Technology , Nanjing 210044, People’s Republic of ChinaSchool of Remote Sensing and Geomatics Engineering, Nanjing University of Information Science and Technology , Nanjing 210044, People’s Republic of ChinaCollege of Surveying & Geo-Informatics, Tongji University , Shanghai 200092, People’s Republic of China; State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology , Macau, People’s Republic of China; The Shanghai Key Laboratory of Space Mapping and Remote Sensing for Planetary Exploration, Tongji University , Shanghai 200092, People’s Republic of ChinaPacific Northwest National Laboratory , Richland, WA, United States of AmericaNorwegian Institute for Nature Research , Trondheim, NorwaySchool of Remote Sensing and Information Engineering, Wuhan University , Wuhan 430079, People’s Republic of ChinaAccurately capturing the impact of urban trees on temperature can help optimize urban heat mitigation strategies. Recently, there has been widespread use of remotely sensed land surface temperature ( T _s ) to quantify the cooling efficiency (CE) of urban trees. However, remotely sensed T _s reflects emitted radiation from the surface of an object seen from the point of view of the thermal sensor, which is not a good proxy for the air temperature ( T _a ) perceived by humans. The extent to which the CEs derived from T _s reflect the true experiences of urban residents is debatable. Therefore, this study systematically compared the T _s -based CE (CE _T _s ) with the T _a -based CE (CE _T _a ) in 392 European urban clusters. CE _T _s and CE _T _a were defined as the reductions in T _s and T _a , respectively, for every 1% increase in fractional tree cover (FTC). The results show that the increase in FTC has a substantial impact on reducing T _s and T _a in most cities during daytime. However, at night, the response of T _s and T _a to increased FTC appears to be much weaker and ambiguous. On average, for European cities, daytime CE _T _s reaches 0.075 °C % ^−1 , which is significantly higher (by an order of magnitude) than the corresponding CE _T _a of 0.006 °C % ^−1 . In contrast, the average nighttime CE _T _s and CE _T _a for European cities are similar, both approximating zero. Overall, urban trees can lower daytime temperatures, but the magnitude of their cooling effect is notably amplified when using remotely sensed T _s estimates compared to in situ T _a measurements, which is important to consider for accurately constraining public health benefits. Our findings provide critical insights into the realistic efficiencies of alleviating urban heat through tree planting.https://doi.org/10.1088/1748-9326/ad30a3urban heat islandsgreen spacein situ measurementsecosystem servicemitigation strategiesremote sensing |
| spellingShingle | Meng Du Niantan Li Ting Hu Qiquan Yang TC Chakraborty Zander Venter Rui Yao Daytime cooling efficiencies of urban trees derived from land surface temperature are much higher than those for air temperature Environmental Research Letters urban heat islands green space in situ measurements ecosystem service mitigation strategies remote sensing |
| title | Daytime cooling efficiencies of urban trees derived from land surface temperature are much higher than those for air temperature |
| title_full | Daytime cooling efficiencies of urban trees derived from land surface temperature are much higher than those for air temperature |
| title_fullStr | Daytime cooling efficiencies of urban trees derived from land surface temperature are much higher than those for air temperature |
| title_full_unstemmed | Daytime cooling efficiencies of urban trees derived from land surface temperature are much higher than those for air temperature |
| title_short | Daytime cooling efficiencies of urban trees derived from land surface temperature are much higher than those for air temperature |
| title_sort | daytime cooling efficiencies of urban trees derived from land surface temperature are much higher than those for air temperature |
| topic | urban heat islands green space in situ measurements ecosystem service mitigation strategies remote sensing |
| url | https://doi.org/10.1088/1748-9326/ad30a3 |
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