由於全球溫室效應造成氣候變遷,都會區則因都市化及工商化等影響,使得各地氣溫不斷上升,進而產生熱島效應,目前已證明每到夏日季節,都市就像一座發熱的島嶼,熱能在都市上空無法消散。水田因湛水,其蒸發散作用旺盛,且熱容量較乾燥地表土壤高,對熱流具有調節作用,能舒緩氣溫、地溫及調節濕度等變異,可對環境產生涼化作用,水體本身也有蒸發行為,再加上溼地,也能產生蒸發散行為。本研究探討在各種土地利用的組合下,水體和濕地對都市環境溫度的影響,都會區的河川堤防處處林立,也探討堤防對河川和溼地的蒸發散有無影響。 本研究應用Landsat-7衛星熱紅外光影像,配合福衛二號地表分類,擷取出地表溫度,再使用S曲線執行回歸統計分析,找出都會區中地表溫度受影響之95%範圍。研究結果顯示,河川水體本身在有堤防阻隔之情況下,對都市環境溫度並無明顯的調節功能,但若加上溼地組合,則最多產生217公尺之影響範圍,所以溼地在都市環境溫度上有降低溫度的效果。
Since the global warming, climate change and the impacts of urbanization, temperatures have been increasing in many places and even resulted in the urban heat island effects, It has been proved that the urban is like a heating island in summertime as heat created faster than dispersed. In the literature, many studies indicated that the major characteristics of paddy fields, ponding water, wet soils created a vigorous evaporation and higher heat capacity which have the function of regulating the heat current. mitigating air and land surface temperature. adjusting humidity and so on. The study was to investigate the environmental temperature impacts under various combinations of land uses, such as rivers, wetland and urban areas, And study the effects of the ubiquitous levees along river in urban areas. The study using Landsat-7 thermal infrared images and the land cover classification from the Formosat II, the land surface temperature was derived and S-curve of regression analysis was employed. The results showed that the water boby of river with a high-rising levee does not have sighificant regulating function to urban temperature. However, in the cases of river associated with wetland, there was an effected range of 217m to the urban temperature. Therefore, the existence of wetland makes a difference of regulating the environmental temperature in urban areas.