IASI observations at the city scale

IASI is a versatile mission, allowing the measurement of both meteorological parameters such as temperature and atmospheric composition for infrared absorbing species. With its long observation record and frequent overpasses, IASI is able to follow changes at different spatial scales. We studied IASI&#8217;s capability to track the anthropogenic signature associated with large cities, both in terms of temperature fingerprint (urban heat islands) and carbon monoxide (CO) content, a good tracer of human activity (transport, heating, and industrial activities). For this study we averaged the IASI data available since the launch of the first IASI, in order to increase the signal to noise, and allow discriminating the city from its surroundings.&#160;For skin temperatures we show that some cities experience much warmer temperatures than nearby rural areas, with day and night differences, whereas other urban areas appear as cold urban islands when surrounded by deserts Examples will be shown and compare with MODIS observations. For CO emitted by human activities, we identified some cities that stand out from their background, and were able to compare their CO associated signatures with measurements provided by other available spaceborne instruments such as Mopitt and TROPOMI.

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The Influence of Vegetation on UHIs, MUHIs, and Microclimate of Selected Southern Cities

HortScience ◽

10.21273/hortsci.32.3.509a ◽

1997 ◽

Vol 32 (3) ◽

pp. 509A-509

Author(s):

Derald A. Harp ◽

Edward L. McWilliams

Keyword(s):

Rural Areas ◽

Urban Areas ◽

Building Materials ◽

Urban Heat Islands ◽

Shopping Malls ◽

Heat Islands ◽

Suburban Areas ◽

Winter Temperatures ◽

Urban Heat ◽

The City

Urban areas have average annual temperatures 2–3°C warmer than surrounding rural areas, with daily differences of 5–6°C common. A suggested reason for this temperature difference is the extensive use of concrete, asphalt, and other building materials in the urban environment. Vegetation can moderate these temperatures by intercepting incoming radiation. The influence of vegetation patterns on the magnitude of urban and micro-urban “heat islands” (UHI and MUHI, respectively) is compared for several cities including Houston, Austin, College Station, and Ft. Worth, Texas; Huntsville, Ala.; and Gainesville, Fla. Temperatures for all cities studied were greatest in the built-up areas and dropped off in suburban areas and adjacent rural areas. In Houston, surrounding rice fields were 3–5°C cooler than urban areas. Heavily built-up areas of Austin were 2–4°C warmer than parks and fields outside of the city. In all of the cities, large parks were typically 2–3°C cooler than adjacent built-up areas. Large shopping malls varied in nocturnal winter and summer temperature, with winter temperatures near door openings 2–3°C warmer, and summer daytime temperatures as much as 17°C cooler beneath trees. This effect seemed to persist at the microclimatic scale. Areas beneath evergreen trees and shrubs were warmer in the winter than surrounding grass covered areas. Video thermography indicated that the lower surfaces of limbs in deciduous trees were warmer than the upper surfaces. Overall, vegetation played a significant role, both at the local and microscale, in temperature moderation.

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Features of the formation of urban heat islands effects in tropical climates and their impact on the ecology of the city

E3S Web of Conferences ◽

10.1051/e3sconf/20199105005 ◽

2019 ◽

Vol 91 ◽

pp. 05005 ◽

Cited By ~ 2

Author(s):

Minh Tuan Le ◽

Nguyen Anh Quan Tran

Keyword(s):

Urban Areas ◽

Building Materials ◽

Urban Landscape ◽

Urban Climate ◽

Ecological Systems ◽

Urban Heat Islands ◽

Heat Islands ◽

Urban Heat ◽

Tropical Climates ◽

The City

The cumulative heating in some urban areas due to the urban growth and its types of industry, energy and transport, is the effect of urban heat island (UHI). It is recognized as one of the characteristics of the urban climate. The temperature increase caused by the effect (UHI) affects the energy flow in urban ecological systems, creates an unusual urban climate. By studying the effects of climate factors, local building materials to optimize energy efficiency, urban landscape, UHI phenomenon could be significantly moderated.

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Automated detection of urban heat islands based on satellite imagery, digital surface models, and a low-cost sensor network

10.5194/egusphere-egu21-14143 ◽

2021 ◽

Author(s):

Sebastian Schlögl ◽

Nico Bader ◽

Julien Gérard Anet ◽

Martin Frey ◽

Curdin Spirig ◽

...

Keyword(s):

Climate Change ◽

Air Temperature ◽

Rural Areas ◽

Urban Areas ◽

Low Cost ◽

Urban Heat Islands ◽

Heat Islands ◽

Micro Scale ◽

Air Temperatures ◽

Urban Heat

Today, more than half of the world&#8217;s population lives in urban areas and the proportion is projected to increase further in the near future. The increased number of heatwaves worldwide caused by the anthropogenic climate change may lead to heat stress and significant economic and ecological damages. Therefore, the growth of urban areas in combination with climate change can increase future mortality rates in cities, given that cities are more vulnerable to heatwaves due to the greater heat storage capacity of artificial surfaces towards higher longwave radiation fluxes.To detect urban heat islands and resolve the micro-scale air temperature field in an urban environment, a low-cost air temperature network, including 450 sensors, was installed in the Swiss cities of Zurich and Basel in 2019 and 2020. These air temperature data, complemented with further official measurement stations, force a statistical air temperature downscaling model for urban environments, which is used operationally to calculate hourly micro-scale air temperatures in 10 m horizontal resolution. In addition to air temperature measurements from the low-cost sensor network, the model is further forced by albedo, NDVI, and NDBI values generated from the polar-orbiting satellite Sentinel-2, land surface temperatures estimated from Landsat-8, and high-resolution digital surface and elevation models.Urban heat islands (UHI) are processed averaging hourly air temperatures over an entire year for each grid point, and comparing this average to the overall average in rural areas. UHI effects can then be correlated to high-resolution local climate zone maps and other local factors.Between 60-80 % of the urban area is modeled with an accuracy below 1 K for an hourly time step indicating that the approach may work well in different cities. However, the outcome may depend on the complexity of the cities. The model error decreases rapidly by increasing the number of spatially distributed sensor data used to train the model, from 0 to 70 sensors, and then plateaus with further increases. An accuracy below 1 K can be expected for more than 50 air temperature measurements within the investigated cities and the surrounding rural areas.&#160;A strong statistical air temperature model coupled with atmospheric boundary layer models (e.g. PALM-4U, MUKLIMO, FITNAH) will aid to generate highly resolved urban heat island prediction maps that help decision-makers to identify local heat islands easier. This will ensure that financial resources will be invested as efficiently as possible in mitigation actions.

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Synergistic Interactions between Urban Heat Islands and Heat Waves: The Impact in Cities Is Larger than the Sum of Its Parts

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-13-02.1 ◽

2013 ◽

Vol 52 (9) ◽

pp. 2051-2064 ◽

Cited By ~ 293

Author(s):

Dan Li ◽

Elie Bou-Zeid

Keyword(s):

Urban Heat Island ◽

Rural Areas ◽

Urban Areas ◽

Heat Waves ◽

Mitigation Strategies ◽

Urban Heat Islands ◽

Heat Island ◽

Heat Islands ◽

Urban Heat ◽

The Impact

AbstractCities are well known to be hotter than the rural areas that surround them; this phenomenon is called the urban heat island. Heat waves are excessively hot periods during which the air temperatures of both urban and rural areas increase significantly. However, whether urban and rural temperatures respond in the same way to heat waves remains a critical unanswered question. In this study, a combination of observational and modeling analyses indicates synergies between urban heat islands and heat waves. That is, not only do heat waves increase the ambient temperatures, but they also intensify the difference between urban and rural temperatures. As a result, the added heat stress in cities will be even higher than the sum of the background urban heat island effect and the heat wave effect. Results presented here also attribute this added impact of heat waves on urban areas to the lack of surface moisture in urban areas and the low wind speed associated with heat waves. Given that heat waves are projected to become more frequent and that urban populations are substantially increasing, these findings underline the serious heat-related health risks facing urban residents in the twenty-first century. Adaptation and mitigation strategies will require joint efforts to reinvent the city, allowing for more green spaces and lesser disruption of the natural water cycle.

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Identification of the urban heat islands phenomenon in a small city: the study case of Três Rios/RJ, Brazil

Revista Brasileira de Ciências Ambientais (Online) ◽

10.5327/z217694781001 ◽

2021 ◽

pp. 1-12

Author(s):

Yuri Matheus Neves Silva ◽

Helder Martins Silva ◽

Raiany Dias De Andrade Silva ◽

Eduardo Duarte Marques ◽

Olga Venimar De Oliveira Gomes

Keyword(s):

Data Collection ◽

Urban Area ◽

Rural Area ◽

Urban Areas ◽

Urban Heat Islands ◽

Socioeconomic Vulnerability ◽

Heat Islands ◽

Large Cities ◽

Urban Heat ◽

Maximum Temperatures

The phenomenon of urban heat islands (UHI) is caused by the increase in temperatures of an urban area as a result of the development of human activities within that area, this phenomenon is usually studied in medium and large cities. This study aims to verify if the phenomenon of UHI occurs in the municipality of Três Rios – RJ, a small sized city. This study included the use of mobile transect, through pre-established data collection points/stations. Five data collection points were selected, from which one was included in a rural area, one in the Parque Natural Municipal (Urban Park, within the city), and three points within the urbanized area. The equipment used was the Brunton® / ADC PRO handheld weather station. The data collection period ranged from September 2018 until July 2019, which included the four seasons. Measurements were taken at 6:00, 12:00, 15:00, 18:00, and 21:00h, in alternate days during the study period. Considering the temperature measurements, two different indicators of thermal variability were used. Strong magnitude heat islands were detected, taking into consideration the relevant variation of maximum temperatures observed in the urban area when compared to the rural area. The results indicate the most affected populations to be the ones located within urban areas, mostly individuals under socioeconomic vulnerability. The results obtained can be used as support for the development of strategies to minimize the thermal discomfort to populations exposed to the influence of higher magnitude urban heat islands.

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The Impact of Green Roofs on the Parameters of the Environment in Urban Areas—Review

Atmosphere ◽

10.3390/atmos10120792 ◽

2019 ◽

Vol 10 (12) ◽

pp. 792 ◽

Cited By ~ 2

Author(s):

Dariusz Suszanowicz ◽

Alicja Kolasa Więcek

Keyword(s):

Urban Areas ◽

Central And Eastern Europe ◽

Single Case ◽

Green Roofs ◽

Urban Heat Islands ◽

Heat Islands ◽

Urban Heat ◽

The Impact ◽

The City

This study presents the results of a review of publications conducted by researchers in a variety of climates on the implementation of ‘green roofs’ and their impact on the urban environment. Features of green roofs in urban areas have been characterized by a particular emphasis on: Filtration of air pollutants and oxygen production, reduction of rainwater volume discharged from roof surfaces, reduction of so-called ‘urban heat islands’, as well as improvements to roof surface insulation (including noise reduction properties). The review of the publications confirmed the necessity to conduct research to determine the coefficients of the impact of green roofs on the environment in the city centers of Central and Eastern Europe. The results presented by different authors (most often based on a single case study) differ significantly from each other, which does not allow us to choose universal coefficients for all the parameters of the green roof’s impact on the environment. The work also includes analysis of structural recommendations for the future model green roof study, which will enable pilot research into the influence of green roofs on the environment in urban agglomerations and proposes different kinds of plants for different kinds of roofs, respectively.

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Habitat Segregation Patterns of Container Breeding Mosquitos: The Role of Urban Heat Islands, Vegetation Cover, and Income Disparity in Cemeteries of New Orleans

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph19010245 ◽

2021 ◽

Vol 19 (1) ◽

pp. 245

Author(s):

Rebeca de Jesús Crespo ◽

Rachel Elba Rogers

Keyword(s):

New Orleans ◽

Low Income ◽

Spatial Scales ◽

Mosquito Species ◽

Climatic Variability ◽

Urban Heat Islands ◽

Mosquito Vector ◽

Heat Islands ◽

Urban Heat ◽

The City

Aedes aegypti and Aedes albopictus are important pathogen-carrying vectors that broadly exhibit similar habitat suitability, but that differ at fine spatial scales in terms of competitive advantage and tolerance to urban driven environmental parameters. This study evaluated how spatial and temporal patterns drive the assemblages of these competing species in cemeteries of New Orleans, LA, applying indicators of climatic variability, vegetation, and heat that may drive habitat selection at multiple scales. We found that Ae. aegypti was well predicted by urban heat islands (UHI) at the cemetery scale and by canopy cover directly above the cemetery vase. As predicted, UHI positively correlate to Ae. aegypti, but contrary to predictions, Ae. aegypti, was more often found under the canopy of trees in high heat cemeteries. Ae. albopictus was most often found in low heat cemeteries, but this relationship was not statistically significant, and their overall abundances in the city were lower than Ae. aegypti. Culex quinquefasciatus, another important disease vector, was also an abundant mosquito species during the sampling year, but we found that it was temporally segregated from Aedes species, showing a negative association to the climatic variables of maximum and minimum temperature, and these factors positively correlated to its more direct competitor Ae. albopictus. These findings help us understand the mechanism by which these three important vectors segregate both spatially and temporally across the city. Our study found that UHI at the cemetery scale was highly predictive of Ae. aegypti and strongly correlated to income level, with low-income cemeteries having higher UHI levels. Therefore, the effect of excessive heat, and the proliferation of the highly competent mosquito vector, Ae. aegypti, may represent an unequal disease burden for low-income neighborhoods of New Orleans that should be explored further. Our study highlights the importance of considering socioeconomic aspects as indirectly shaping spatial segregation dynamics of urban mosquito species.

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Surface Urban Heat Islands Dynamics in Response to LULC and Vegetation across South Asia (2000–2019)

Remote Sensing ◽

10.3390/rs13163177 ◽

2021 ◽

Vol 13 (16) ◽

pp. 3177

Author(s):

Talha Hassan ◽

Jiahua Zhang ◽

Foyez Ahmed Prodhan ◽

Til Prasad Pangali Sharma ◽

Barjeece Bashir

Keyword(s):

Urban Heat Island ◽

Rural Areas ◽

Land Surface ◽

Urban Areas ◽

Vegetation Index ◽

Thermal Environment ◽

Urban Heat Islands ◽

Heat Island ◽

Heat Islands ◽

Urban Heat

Urbanization is an increasing phenomenon around the world, causing many adverse effects in urban areas. Urban heat island is are of the most well-known phenomena. In the present study, surface urban heat islands (SUHI) were studied for seven megacities of the South Asian countries from 2000–2019. The urban thermal environment and relationship between land surface temperature (LST), land use landcover (LULC) and vegetation were examined. The connection was explored with remote-sensing indices such as urban thermal field variance (UTFVI), surface urban heat island intensity (SUHII) and normal difference vegetation index (NDVI). LULC maps are classified using a CART machine learning classifier, and an accuracy table was generated. The LULC change matrix shows that the vegetated areas of all the cities decreased with an increase in the urban areas during the 20 years. The average LST in the rural areas is increasing compared to the urban core, and the difference is in the range of 1–2 (°C). The SUHII linear trend is increasing in Delhi, Karachi, Kathmandu, and Thimphu, while decreasing in Colombo, Dhaka, and Kabul from 2000–2019. UTFVI has shown the poor ecological conditions in all urban buffers due to high LST and urban infrastructures. In addition, a strong negative correlation between LST and NDVI can be seen in a range of −0.1 to −0.6.

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Identificação de Ilhas de Calor na Cidade de Campina Grande-PB Utilizando Sensoriamento Remoto (Identification of Heat Islands in Campina Grande City-PB Using Remote Sensing)

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v9.2.p614-626 ◽

2016 ◽

Vol 9 (2) ◽

pp. 614 ◽

Cited By ~ 2

Author(s):

Elânia Daniele Silva Araújo

Keyword(s):

Remote Sensing ◽

Surface Temperature ◽

Rural Areas ◽

Urban Areas ◽

Spatial And Temporal Variability ◽

Heat Islands ◽

Social Nature ◽

Spatial Changes ◽

Remote Sensing Techniques ◽

The City

A intensa urbanização causa diversos problemas de natureza ambiental, climática e social. O crescimento não planejado da população urbana e a remoção da vegetação são fatores que intensificam estes problemas. As temperaturas na cidade são significativamente mais quentes do que as suas zonas rurais circundantes devido às atividades humanas. As intensas mudanças espaciais em áreas urbanas, promovem significativo aumento na temperatura, causando o chamado efeito de Ilha de Calor Urbano (ICU). Campina Grande é uma cidade de tamanho médio que experimentou um crescimento desordenado, desde o tempo do comércio de algodão e, como qualquer cidade de grande ou médio porte, sofre alterações em seu espaço. Dessa forma, este estudo teve por objetivo analisar a variabilidade espaço-temporal da temperatura da superfície (Ts) e detectar ICU, através de técnicas de sensoriamento remoto. Para o efeito, foram utilizadas imagens dos satélites Landsat 5 e 8, dos anos de 1995, 2007 e 2014. Aumentos da Ts foram bem evidentes e foram detectadas duas ICU. Campina Grande mostra um padrão de tendência: o crescimento urbano não planejado é responsável por mudanças no ambiente físico e na forma e estrutura espacial da cidade, o que se reflete sobre o microclima e, em última análise, na qualidade de vida das pessoas. ABSTRACT The intense urbanization causes several problems of environmental, climate and social nature. The unplanned growth of urban population and the vegetation removal are factors that deepen these problems. Temperatures in the city are significantly warmer than its surrounding rural areas due to human activities. Large spatial changes in urban areas promote significant increase in temperature, causing the so-called Urban Heat Island effect (UHI). Campina Grande is a medium-sized town that experienced an uncontrolled growth since the time of the cotton trade and like any large or medium-sized city, undergoes changes in its space. Therefore, this study aimed to analyze surface temperature spatial and temporal variability and to detect potential UHI, through remote sensing techniques. Spectral images from Landsat 5 and 8 satellites were used. Using images from years 1995, 2007 and 2014, considerable increases in temperature were identified and two UHI were recognize. Campina Grande shows a trend pattern: the urban unplanned growth is responsible for changes in the physical environment and in the form and spatial structure of the city, reflecting on people quality of life. Keywords: change detection, surface temperature, heat islands, urbanization.

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Study of Vortex Systems as a Method to Weakening the Urban Heat Islands within the Financial District in Large Cities

Sustainability ◽

10.3390/su132313206 ◽

2021 ◽

Vol 13 (23) ◽

pp. 13206

Author(s):

Luis Rodriguez-Lucas ◽

Chen Ning ◽

Marcelo Fajardo-Pruna ◽

Yugui Yang

Keyword(s):

Rural Areas ◽

Large Scale ◽

Flow Characteristics ◽

Maximum Velocity ◽

Vortex Generator ◽

Urban Heat Islands ◽

Navier Stokes ◽

Specific Work ◽

Heat Islands ◽

Large Cities

This paper presents a new concept called the urban vortex system (UVS). The UVS couples a vortex generator (V.G.) that produces updraft by artificial vortex and a vortex stability zone (VSZ) consisting of an assembly of four buildings acting as a chimney. Through this system, a stable, upward vortex flow can be generated. The Reynolds Averaged Navier–Stokes (RANS) simulation was carried out to investigate the flow field in the UVS. The Renormalized Group (RNG) k–ε turbulent model was selected to solve the complex turbulent flow. Validation of the numerical results was achieved by making a comparison with the large-size experimental model. The results reported that a steady-state vortex could be formed when a vapor-air mixture at 2 m/s and 450 K enters the vortex generator. This vortex presented a maximum negative central pressure of −6.81 Pa and a maximum velocity of 5.47 (m/s). Finally, the similarity method found four dimensionless parameters, which allowed all the flow characteristics to be transported on a large scale. The proposed large-scale UVS application is predicted to be capable, with have a maximum power of 2 M.W., a specific work of 3 kJ/kg, buildings 200-m high, and the ability to generate winds of 6.1 m/s (20 km/h) at 200 m up to winds of 1.5 m/s (5 km/h) at 400 m. These winds would cause the rupture of the gas capsule of the heat island phenomenon. Therefore, the city would balance its temperature with that of the surrounding rural areas.

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