Study on the urban heat island in Sofia City: Numerical simulations with potential natural vegetation and present land use data

Vitanova, Lidia Lazarova; Kusaka, Hiroyuki

doi:10.1016/j.scs.2018.03.012

Cited by 18 publications

(7 citation statements)

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“…In addition, advanced computer technology along with high spatial and temporal resolution of satellite imagery has been used to measure UHIs in more detail [52,53]. The UHI phenomenon can also be studied by using numerical atmospheric simulation (climate) models [54][55][56][57][58][59][60]. The latter approach provides a unique ability to study the response of various land-cover change scenarios on UHI.…”

Section: Introductionmentioning

confidence: 99%

The Sensitivity of Urban Heat Island to Urban Green Space—A Model-Based Study of City of Colombo, Sri Lanka

et al. 2019

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Urbanization continues to trigger massive land-use land-cover change that transforms natural green environments to impermeable paved surfaces. Fast-growing cities in Asia experience increased urban temperature indicating the development of urban heat islands (UHIs) because of decreased urban green space, particularly in recent decades. This paper investigates the existence of UHIs and the impact of green areas to mitigate the impacts of UHIs in Colombo, Sri Lanka, using UrbClim, a boundary climate model that runs two classes of simulations, namely urbanization impact simulations, and greening simulations. The urbanization impact simulation results show that UHIs spread spatially with the reduction of vegetation cover, and increases the average UHI intensity. The greening simulations show that increasing green space up to 30% in urban areas can decrease the average air temperature by 0.1 °C. On the other hand, converting entire green areas into urban areas in suburban areas increases the average temperature from 27.75 °C to 27.78 °C in Colombo. This demonstrates the sensitivity of UHI to vegetation cover in both urban and suburban areas. These seemingly small changes are average grid values and may indicate much higher impacts at sub-grid levels.

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Section: Introductionmentioning

confidence: 99%

The Sensitivity of Urban Heat Island to Urban Green Space—A Model-Based Study of City of Colombo, Sri Lanka

et al. 2019

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“…The results of the control simulation (case LU2012) were validated against actual observations. While the simulation data used for the LU2012 case are the same as those of the control case reported by Vitanova and Kusaka (2018), the validation approach differed slightly. The results show that the WRF model satisfactorily reproduced the hourly average surface air temperatures and relative humidity (RH) at four observation stations over the month of July consistently for the period 2011–2013 (Figure 3; see Figures 1b and 2b for locations).…”

Section: Resultsmentioning

confidence: 99%

“…This study focuses on the largest Bulgarian city, Sofia. In recent decades, very few studies have been conducted on the thermal environment and UHIs in Sofia (e.g., Dimitrova et al, 2019; Kolev et al, 2000; Pongrácz et al, 2009; Syrakova & Zaharieva, 1998; Vitanova & Kusaka, 2018). However, there have been no research studies vis‐a‐vis Sofia on how urbanization alters the UHI effect and human thermal sensitivity.…”

Section: Introductionmentioning

confidence: 99%

How urban growth changes the heat island effect and human thermal sensations over the last 100 years and towards the future in a European city?

Vitanova

Kusaka

Doan

et al. 2021

Meteorological Applications

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Urban development exacerbates urban heat island effects of cities and thermal discomfort of the residents worldwide. However, such urban effects vary with the geographical and climatic conditions of the respective cities. This study is the first to quantitatively estimate the impact of past (1878), present (2012), and future (2050) urbanization on surface air temperatures and human thermal comfort in Sofia, the largest city of Bulgaria. We used the state‐of‐the‐art Weather Research and Forecasting (WRF) climate model, with a 1‐km horizontal resolution for three cases: LU1878, LU2012, and LU2050. We first validated the results of the control simulation (case LU2012) against actual observations. The model satisfactorily reproduced the diurnal variation of the observed monthly mean surface air temperatures for July (2011–2013) with a mean bias of ±0.6°C. We then estimated the potential impacts of past and future urbanization on surface temperature. Our results suggest that because of urbanization of Sofia, the surface air temperature at 0600 Local Standard Time (LST) has increased approximately 4.0°C in the past (1878–2012) and approximately 0.4°C in future (2012–2050). We also evaluated the impact of the urban thermal environment on human comfort levels. Considering the LU2050 case in the central part of Sofia, the temperature–humidity index during mid‐afternoon (1400–1700 LST) is estimated to be 24–26, indicating that approximately 50% of the residents could feel perceptibly uncomfortable.

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“…For example, many single-family houses have now been replaced with [5][6][7] floor buildings in residential neighborhoods, and many available open green spaces have been converted into built up and impervious areas. Attempts have been made to study the effect of urbanization in Sofia on biodiversity [3], population growth and density [4][5][6], economic, spatial and demographic trends in the urban systems [7], theoretical aspects of sustainable development of urban areas [8], and urban heat island effects [9]. To the best of our knowledge, no detailed study has evaluated the impact of urbanization on the local meteorological conditions and different scenarios of future urban development in Sofia; the importance of the aforementioned problems is the motivation for this work.…”

Section: Introductionmentioning

confidence: 99%

Modeling the Impact of Urbanization on Local Meteorological Conditions in Sofia

et al. 2019

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Increasing urbanization impacts the local meteorology and the quality of life for residents. Urban surface characteristics and anthropogenic heat stress lead to urban heat island effects, changes in local circulations, precipitation alteration, and amendment of the local fluxes. These modifications have a direct effect on the life and health of residents. In this study, we assessed the impact of urbanization in Sofia (Bulgaria) using the Weather Research and Forecasting (WRF) model at 500 m resolution for the summer period of 2016. We utilized the CORINE (coordination of information on the environment) 2012 land cover database to represent the urban areas in four detailed land cover types, i.e., high-intensity residential areas, low-intensity residential areas, medium/industrial areas, and developed open spaces. We performed two experiments; in the first, we substituted an urban area with the most representative rural land cover to delineate the current impact of urbanization, while in the second, we replaced the existing built-up area (all four categories) with a hypothetical scenario of high-density residential land cover showing aggressive urban development. These experiments addressed the impact of land use changes as well as the extreme effects of ongoing high-density construction on the local meteorological conditions. The results showed that urban temperatures can increase by 5 °C and that moisture can decrease by 2 g/kg in the central part of Sofia in comparison to surrounding rural areas. The results also showed that building higher and dense urban areas can significantly increase heat flux and add additional stress to the environment.

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Study on the urban heat island in Sofia City: Numerical simulations with potential natural vegetation and present land use data

Cited by 18 publications

References 55 publications

The Sensitivity of Urban Heat Island to Urban Green Space—A Model-Based Study of City of Colombo, Sri Lanka

The Sensitivity of Urban Heat Island to Urban Green Space—A Model-Based Study of City of Colombo, Sri Lanka

How urban growth changes the heat island effect and human thermal sensations over the last 100 years and towards the future in a European city?

Modeling the Impact of Urbanization on Local Meteorological Conditions in Sofia

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