井孔溫度量測可幫助我們建立地下溫度場的分布，在地下水流動顯著的地區，可反應出地下水的流場，另外，也可用來反推地表溫度歷史。本研究總共量測了屏東平原48 口觀測井的井孔溫度，結果顯示溫度最低為高樹井（23.5℃），位於荖濃沖積扇的扇頂補注區，分布深度約為地面下90-100m深。屏東平原的地溫呈現北邊較低、南邊較高，反應出補注區冷水流入的影響。48 口井中有40 口都呈現上段變暖，但這些井大都受到地下水流動的影響，不適合定量的地表暖化分析。只有3 口井的地溫梯度界於2.0-3.5 ℃/100m 之間，地表暖化分析結果顯示，反曲點H 的深度約45-63m、始初地表溫度約23.9-25.5℃、現在地表溫度約25.8-27.5℃、增加溫度約1.9-3.0℃、增溫時間約65-89 年。此次研究結果為首次調查，還有許多的不確定性，未來若進行第2 次調查，累積2 次的時間變化，應可對於屏東平原補注的水流場，及地表溫度變化對地溫的影響，有些定量的結果。 Subsurface temperature distribution determined by measuring boreholes temperature could be used to infer direction of groundwater flow or to invert the ground surface temperature history. This research investigates borehole temperature of 48 groundwater monitoring wells in Pingtung Plain, southern Taiwan. The results show that the lowest temperature is about 23.5 °C with a depth of 90-100m below surface in the Kaushu Well located at the upper fan recharge area of the Loanon alluvial fan. The subsurface temperature in Pingtung Plain is lower in the recharge area of northern part and higher to the downstream side of southern part. There are 40 wells in the total of 48 wells that show a trend of warming upward. Most of these wells were affected by groundwater flow, only 3 wells can be used for surface temperature history analysis. For analyzing the 3 wells, we determine the initial surface temperatures are approximately 23.9-25.5 °C, the current surface temperature are 25.8-27.5 °C, and the surface temperature were increased by 1.9-3.0 °C during a period of 65-89 years.
