臺中市舊市區都市結構與分析單元尺度對都市熱島效應之影響

Abstract

隨著全球氣候變遷加劇，都市熱島效應已成為各國高度關注之議題。IPCC第六次評估報告指出，都市化與高密度開發使城市更易暴露於極端氣候風險中，亟需透過空間規劃與政策加以調適。臺灣近年高溫頻率與強度顯著增加，臺中市近30年氣溫上升幅度亦顯著，顯示其熱風險加劇且尚未有效緩解。為精進都市熱島研究方法與實務應用，本研究以Landsat 8影像反演地表溫度，並以標準差法劃定熱島變遷區位。針對既有研究多著重單一尺度與資料格式之限制，納入多尺度變數交互探討。研究變數整合二維與三維都市結構指標，使用60公尺網格至村里等五種尺度比較分析，並透過相關性檢定與普通最小平方法（OLS）篩選解釋力變數，再以地理加權迴歸（GWR）探討空間異質性與尺度效應。本研究結果顯示，都市結構變數對地表溫度的尺度效應顯著。GWR分析指出，不同都市結構變數對地表溫度的影響因地制宜，具明顯的區位差異性，二維指標與三維指標皆具有良好解釋能力，其中建物高度碎形值與利用建物高度加權的容積率，本研究認為可作為綜合法規規定與都市現況結構的關鍵變數。研究結果也指出網格尺度具高解析優勢，一級發布區則兼顧統計意義與實務規劃應用。本研究建立多尺度、多維度都市結構與地表溫度之關聯模式，補足現有熱島研究在尺度與資料格式上的不足，並以建物高程為核心探討其對地表溫度影響，提供亞熱帶城市熱風險調適與規劃參考。建議未來都市計畫、都市更新及都市設計審議等法規檢討時，納入不同尺度之熱環境分析，以提升城市氣候韌性。

Urban heat island (UHI) effects have become a critical issue globally. The IPCC Sixth Assessment Report highlights that urbanization and dense development increase cities’ vulnerability to extreme climate, underscoring the urgency of spatial adaptation. In Taiwan, high-temperature events have intensified in recent years. Taichung City, for example, has experienced significant warming over the past 30 years, reflecting escalating heat risks that remain insufficiently addressed.To advance UHI research, this study retrieved land surface temperature (LST) from Landsat 8 and identified UHI change areas using the standard deviation method. To overcome limitations of single-scale analysis and data format, two- and three-dimensional urban structure variables were analyzed across five spatial scales (60 m grids to village-level units). Correlation tests and OLS were used to select explanatory variables, and GWR was applied to assess their spatially varying relationships with LST, along with spatial heterogeneity and scale effects.The results show significant scale effects of urban structure variables on LST. GWR reveals clear spatial differences and demonstrates strong explanatory power for both 2D and 3D urban structure variables.The study concludes that building height fractal dimension and height-weighted floor area ratio are key urban structure variables linking planning regulations with the built environment. Grid-based scales provide high-resolution detail for analysis, while Level-1 dissemination areas balance statistical robustness and planning relevance.This study establishes a multi-scale, multi-dimensional framework linking urban structure and LST, addressing gaps in scale and data format. Building height emerged as a key factor influencing the urban thermal environment. The study recommends incorporating multi-scale thermal analyses into urban planning, renewal, and design review to enhance climate resilience.