Quantifying the impacts of vegetation structures on the climate performance of informal green spaces : a case study of Dresden, Germany
Rivera, Rosalynd (2024)
2024
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2024101326416
https://urn.fi/URN:NBN:fi:amk-2024101326416
Tiivistelmä
The 2019 IPCC report highlights that anthropogenic activities have caused a global temperature increase of approximately 1.0°C, with Urban Heat Island (UHI) effects intensifying temperature rises in cities. Vegetation, particularly in Informal Green Spaces (IGS), mitigates UHI by providing cooling benefits and enhancing urban microclimates similar to Formal Green Spaces (FGS). This study addresses the knowledge gap regarding the microclimatic performance of IGS by examining their Vegetation Structures (VS) and air temperature regulation capabilities.
The primary objectives of the dissertation are to highlight IGS's role in providing regulating services, quantify air temperature variations among different VS within IGS, investigate correlations, and propose integration strategies for IGS in greenspace planning. Three study sites in Dresden, Germany, were chosen based on criteria including Local Climate Zones (LCZ), size, IGS typology, and accessibility. The research employs a mixed-methods approach, including remote sensing, in-situ air temperature (AT) measurements via traverse study, and qualitative visual assessments of VS. The AT values are then compared to two variables: Vegetation Structure (VS) and Canopy Cover (CC).
The findings indicate that IGS contribute to temperature regulation, with CC playing a crucial role in cooling. Correlations showed that lower and more stable afternoon temperatures were more associated with CC than VS. However, the low R² values suggest that other variables not examined in the study might have had more significant effects on the results. These may include vegetation health, built surfaces, and the surrounding urban form. The results also found that different types of vegetation and their spatial arrangement can provide both cooling and warming effects. For instance, grasslands and meadows can significantly reduce temperatures through the albedo effect and enhanced wind flow, while tall dense shrubs and grasses can trap heat, especially near anthropogenic heat sources. Furthermore, larger green spaces in less built-up areas are observed to offer more consistent cooling.
Finally, the conclusions from the study have revealed directions for the management and integration of IGS in the greenspace planning of Dresden. This includes incorporating IGS into green space inventories, engaging stakeholders in management, and conducting further studies on Leaf Area Index (LAI) and thermal comfort benefits of IGS. In addition, future research should consider longer observation periods, consistent measurement timings, and a comprehensive evaluation of the diverse ecosystem services provided by IGS. Detailed studies of urban morphology around green spaces and microclimate simulations to compare with in-situ measurements are also suggested.
The primary objectives of the dissertation are to highlight IGS's role in providing regulating services, quantify air temperature variations among different VS within IGS, investigate correlations, and propose integration strategies for IGS in greenspace planning. Three study sites in Dresden, Germany, were chosen based on criteria including Local Climate Zones (LCZ), size, IGS typology, and accessibility. The research employs a mixed-methods approach, including remote sensing, in-situ air temperature (AT) measurements via traverse study, and qualitative visual assessments of VS. The AT values are then compared to two variables: Vegetation Structure (VS) and Canopy Cover (CC).
The findings indicate that IGS contribute to temperature regulation, with CC playing a crucial role in cooling. Correlations showed that lower and more stable afternoon temperatures were more associated with CC than VS. However, the low R² values suggest that other variables not examined in the study might have had more significant effects on the results. These may include vegetation health, built surfaces, and the surrounding urban form. The results also found that different types of vegetation and their spatial arrangement can provide both cooling and warming effects. For instance, grasslands and meadows can significantly reduce temperatures through the albedo effect and enhanced wind flow, while tall dense shrubs and grasses can trap heat, especially near anthropogenic heat sources. Furthermore, larger green spaces in less built-up areas are observed to offer more consistent cooling.
Finally, the conclusions from the study have revealed directions for the management and integration of IGS in the greenspace planning of Dresden. This includes incorporating IGS into green space inventories, engaging stakeholders in management, and conducting further studies on Leaf Area Index (LAI) and thermal comfort benefits of IGS. In addition, future research should consider longer observation periods, consistent measurement timings, and a comprehensive evaluation of the diverse ecosystem services provided by IGS. Detailed studies of urban morphology around green spaces and microclimate simulations to compare with in-situ measurements are also suggested.