Analysis of Human Heat Stress in Sri Lanka: Using Temperature Humidity Index (THI)

Nanayakkara, N. W. Srimalee; Nianthi, K. W. G. Rekha

doi:10.29322/ijsrp.8.9.2018.p8184

Cited by 3 publications

(3 citation statements)

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“…Climate change is likely to bring mainly temperature increases in Sri Lanka -It might increase the Human Heat Stress (HHS) on the island. The highest positive significant increasing trend of temperature humidity index (THI) was noticed at Kundasale (R 2 0.83) in Kandy [13]. Kandy Lake minimize the rise of temperature by reducing heat stress in the Kandy City.…”

Section: Resultsmentioning

confidence: 99%

Spatial and temporal variation of land surface temperature (LST) in the Kandy District of Sri Lanka

Rashmika Nawarathna,

Nianthi,

Subasinghe

2023

IOP Conf. Ser.: Earth Environ. Sci.

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In Sri Lanka, there is a considerable increase in the average annual LST in the city of Colombo, and it might have occurred in the city of Kandy as well. Increases in LST can affect to many issues. Research on LST is useful for green city planning and policymaking for development in urban areas. This study examined the spatial and temporal variation of LST in the Kandy District in 1996 and 2017. Geospatial tools such as remote sensing and GIS were used to analyse data. Landsat satellite data has been collected by the United States Geological Survey. The NDVI, NDBI, and NDWI were used to classify the different land uses and to find out the relationships between LST. The mean LST was increased by 2.36°C in 2017 compared to 1996. The LST was higher in the City of Kandy in 2017 than in 1996. The Eastern part of the Kandy was slightly higher in 2017 than in 1996. There is a significant negative correlation (α=0.01) between LST and NDVI. The NDBI increased by 0.11 in 2017, compared to 1996 and spread into suburb areas. The significant strong relationship between NDBI and LST was identified. The lack of satellite images is one of the serious barriers to analysing the LST. Land-use changes, increased build-up areas and decreases in vegetation and water bodies have affected to rise in land surface temperature in the Kandy. The future land use planning should be considered to mitigate the effects of LST in Kandy City.

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Section: Resultsmentioning

confidence: 99%

Spatial and temporal variation of land surface temperature (LST) in the Kandy District of Sri Lanka

Rashmika Nawarathna,

Nianthi,

Subasinghe

2023

IOP Conf. Ser.: Earth Environ. Sci.

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“…Perera, N. and Emmanuel (2018) have highlighted the importance of integrating the local level planning process in climatic-responsive urban design to control the increasing trend of urban heat in tropical cities. Sri Lanka is a warm-humid tropical country where increasing heat stress in Temperature Humidity Index (THI) (from 1931-1961 to 2006-2016) has been recorded, resulting in several complications of health of the people in cities (Nanayakkara and Nianthi, 2018). Colombo is the capital city where vulnerability is high due to fast urbanization.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Planting Arrangement on Outdoor Thermal Comfort

Dissanayake,

LWG,

UGD

2023

IRSPSD International

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Vegetation provides significant benefits for urban thermal environments attracting people to open spaces. Especially in tropical climates, squares are more vulnerable to thermal discomfort due to surrounding buildings and increased hard surface coverage compared to urban parks. Since the space for planting is limited, a proper arrangement is essential to enhance the outdoor thermal comfort (OTC). Nevertheless, the impact of different planting arrangements on OTC has not yet been adequately discovered in tropics. This research conducts numerical simulations using ENVI-met software employing physiological equivalent temperature (PET) to understand how planting patterns affect microclimate and OTC at pedestrian level (1.5m) under clustered, scattered, and equally distributed planting arrangements. The methodology includes three stages; onsite measurements, assessment of existing OTC level, and comparison of the impact of planting arrangements on microclimate and OTC. The changes in the planting arrangements considerably affect OTC in urban outdoors altering the air temperature (Ta), wind speed (WS), mean radiant temperature (MRT), and relative humidity (RH). MRT and the WS are found as the most important parameters influencing thermal comfort, thus collaborating with previous studies. Equally distributed planting arrangement has a significant impact providing the highest comfort improvement (9.8 ℃ PET reduction) at the pedestrian level. Reduced canopy overlaps and planting densities, and improved homogeneous shade coverage and ventilation are suggested to overcome thermal discomfort. The cooling effect of native tree species should be assessed in future research. These results guide urban designers and landscape architects in improving microclimate and OTC in warm-humid cities.

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“…The hot weather is dangerously growing [22]. Today Sri Lanka also faced a highly stressful situation with heat stress [23][24][25]. The trend of mean annual temperatures has been increasing in all meteorological stations in the country.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Urban Heat Island Effect, Heat Stress and Public Health in Colombo, Sri Lanka and Shenzhen, China

Nanayakkara

Wang²,

Cao

et al. 2023

Atmosphere

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Human health, energy and comfort are determined by the climate that remains in the physical environment. Regarding urban climate, few studies assess the urban heat island effect, heat stress, and public health as geographical representations. This study seeks to fill this gap by selecting Colombo, Sri Lanka, and Shenzhen, China, comparatively, two coastal cities with different climate conditions. We quantified and compared the effects of heat waves and their impacts on public health and the effect of urbanization on urban heat islands (UHI). Heat-related public health issues have been calculated using the Wet-Bulb Globe Temperature (WBGT) index. The Urban Heat Island (UHI) effect was analyzed using Land Surface Temperature (LST), created based on Landsat images obtained in 1997, 2009 and 2019. A rapid increase in temperature and humidity creates an uncomfortable environment in both cities, but apparent differences can be observed in climatic phenomena. During the summer (June to August), the prevailing atmospheric condition in Shenzhen makes a “Very severe stress” with Heatstroke highly likely. Nevertheless, seven months (November to April) are found as “Comfortable” without having any heat-related health injuries. However, Colombo has never been classified as “Comfortable” throughout the year. Out of twelve, five months (April to August) are found as “Very severe stress” with Heatstroke highly likely. When considering the urban expansion and UHI, a fast expansion can be observed in Colombo than in Shenzhen. Consequently, with the more severe heat-related public health and rapid urban heat island expansion, Colombo makes it more stressful than Shenzhen city. Our findings highlight the comparison between heat-related public health and urban heat island between two coastal cities with different climate conditions and under rapid urbanization processes. Therefore, it is imperative to assess these risks and respond effectively.

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Analysis of Human Heat Stress in Sri Lanka: Using Temperature Humidity Index (THI)

Cited by 3 publications

References 0 publications

Spatial and temporal variation of land surface temperature (LST) in the Kandy District of Sri Lanka

Spatial and temporal variation of land surface temperature (LST) in the Kandy District of Sri Lanka

The Influence of Planting Arrangement on Outdoor Thermal Comfort

Analysis of Urban Heat Island Effect, Heat Stress and Public Health in Colombo, Sri Lanka and Shenzhen, China

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