Assessing the Efficacy of Urban Green Roofs in Mitigating Heat Island Effects and Enhancing Biodiversity in Mid-Sized Cities Using Remote Sensing and GIS

Project Abstract

Urban green roofs (UGRs) are increasingly deployed as nature-based solutions to mitigate urban heat island (UHI) effects and to bolster urban biodiversity, yet their performance in mid-sized cities remains underexplored. This study employs a mixed-methods approach integrating remote sensing, geographic information systems (GIS), microclimate measurements, and biodiversity assessments to quantify the thermal regulation and ecological value of UGRs across a representative sample of mid-sized cities. The research leverages high-resolution multispectral and thermal imagery to characterize roof typologies, vegetation cover, albedo, evapotranspiration, and heat flux dynamics under varying seasonal and meteorological conditions. A standardized UGR index was developed to normalize design variables (substrate depth, plant species, irrigation regime, and substrate insulation) and to enable cross-city comparisons. Thermal maps were corroborated with in-situ measurements from automated weather stations and roof surface sensors to derive diurnal and seasonal UHI modification attributable to UGRs. Biodiversity outcomes were assessed using standardized rapid bioassessment protocols for flora and arthropods, complemented by remote sensing-derived proxies for habitat complexity and green connectivity. Spatial analyses examined the contribution of UGRs to surface temperature reduction, humidity retention, and potential cooling duration, as well as their role in supporting pollinator networks and insect diversity. Findings indicate that mature, structurally complex roofs with diverse plant assemblages can reduce roof surface temperatures by X to Y degrees Celsius during peak heat periods and create localized refugia for non-urban avifauna and invertebrate taxa, though performance is highly contingent on substrate depth, irrigation management, and surrounding urban morphology. The study reveals a positive correlation between higher vegetation productivity on green roofs and ecological indicators such as species richness and evenness, suggesting that design strategies emphasizing plant diversity and vertical habitat complexity yield greater biodiversity benefits. Economic and policy analyses assess installation, maintenance costs, energy savings, and potential co-benefits for stormwater management and air quality. The integrative model demonstrates that synergistic design—combining passive cooling through high-coverage vegetation, evaporative cooling via substrate moisture, and microclimate buffering through roof insulation—enhances UHI mitigation while sustaining urban ecological networks. Sensitivity analyses identify key drivers and limits of effectiveness under climate projections, informing scalable, cost-efficient implementation guidelines for mid-sized cities. The research contributes a transferable methodology for cross-city evaluation of UGR performance, offers empirical benchmarks for policy makers, planners, and building owners, and provides actionable recommendations for optimizing UGR designs to maximize thermal resilience and biodiversity conservation in urbanizing landscapes.

Project Overview

What This Project Is About

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A plain-language overview of the topic and what the project investigates.

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The Problem It Addresses

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What problem or gap this project tackles and why it matters to the field or society.

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Objectives of the Project

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1. Identify how green roofs affect local temperatures in mid-sized cities.
2. Evaluate changes in biodiversity on and around green roofs.
3. Explore how remote sensing and GIS tools can measure these effects.
4. Provide practical guidelines for designing effective green roofs.

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What You Will Do Step by Step

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1. Review existing literature on urban heat islands, green roofs, biodiversity, and GIS methods.
2. Collect data on building roofs, vegetation types, and climate metrics for selected cities.
3. Use satellite imagery and GIS to map roof green cover and surface temperatures.
4. Analyze correlations between green roofs and local temperature changes.
5. Assess biodiversity indicators through field checks or existing databases.
6. Synthesize findings to compare city contexts and roof designs.
7. Formulate design recommendations for policymakers and practitioners.

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Expected Outcome

Anticipated results include a clearer link between green roofs and reduced heat and higher biodiversity, plus actionable guidelines for city planners.