都市人造表面覆蓋率之解析、預測與控制

Analysis, Prediction, and Control of the Artificial Cover Ratio in Cities in Taiwan

人造表面覆蓋率（artificial cover ratio, ACR）主要用於解析都市熱平衡、都市熱島現象、都 市擴張現象與都市生態環境等相關課題，而地表不透水率（impervious surface ratio, ISR）主要用 於評估地表逕流量與都市洪水現象，許多研究亦以 ISR 評估 ACR 相關課題。本研究試圖釐清 兩者的定義與差異性，提出 ACR 與 ISR 之關係式；另一方面，應用遙測影像分類法，估算台 北市、台中市、台南市與高雄市各行政區之土地覆蓋組成、ACR、綠覆率（green cover ratio, GCR）、藍覆率（blue cover ratio, GCR）與藍綠覆率（blue and green cover ratio, BGR）等資料，有效 樣本數為 37 個，並彙整各市政府統計要覽資料，進行 ACR 迴歸分析，提出四項 ACR 單迴歸 公式與兩項 ACR 複迴歸公式，作為都市規劃者在描述、預測與控制都市 ACR 相關工作之參 考。與 ACR 呈正相關的因子主要有 ln（人口密度），而呈現負相關的有 GCR、BGR 以及林野、 耕地與公園面積比。本研究建議進行都市規劃與設計時，留設適當的都市藍綠帶面積比，以維 持良好的物理環境與生態環境品質；在新訂或通盤檢討都市計畫，可參考本研究所提出的 ACR 迴歸式，以有效預測與控制都市 ACR；在建築管制的層面，建議推廣綠屋頂政策，以降低都 市人造面覆蓋率，進而達到都市降溫與基地保水等目標。

The artificial cover ratio (ACR) is used mainly to analyze urban heat balance, the urban heat island phenomenon, urban sprawl phenomenon, and urban eco-environment. The impervious surface ratio (ISR) is commonly used to assess urban water runoff, urban flooding and other issues associated with the ACR. This study indentifies differences between the ACR and ISR, and presents novel equation for deriving the ACR and ISR. The satellite remote sensing method is used to estimate land cover components in each district in Taipei, Taichung, Tainan, and Kaohsiung cities. Land cover data for 37 districts are obtained. Statistical data from local governments were used in ACR regression analysis. Four regression equations and two multi-regression equations are presented to help urban planners and government officials describe, predict, and control the ACR in urban areas. To maintain a suitable physical and ecological environment in urban areas, defining a suitable ratio of urban green space to blue-system areas is very important. When making or revising an urban plan, ACR regression equations are very useful for predicting or controlling the ACR. In the field of building control, a roof garden policy can reduce the ACR, cool urban air temperature and reduce the imperviousness of urban surfaces.