- 期刊
水田生態環境微氣候之量測與數值模擬
Measurement and Numerical Simulation of Paddy Field Ecoenvironment and Microclimate
摘要
本研究針對水田生態環境微氣候進行實際量測與數值模擬，並評估水田區不同土地利用對區域性微氣候之影響。本研究為更精確模擬水田生態環境之溫度及濕度變化，乃以簡易生物圈(SiB2)模式架構修改先前之植物大氣土壤模式PASSM，採用電流概念模擬植物群內可感熱流及蒸發潛熱流之傳輸，考慮湛水層及深層土壤之熱流機制，並採用較合理之葉面積分布型態及葉面傾斜校正係數計算植物所吸收之輻射量，另外在地溫計算方面，採用深層土溫校正地表溫度，而深層土溫則以實測資料搭配週期函數模擬溫度變化。本研究並以試驗田區實測之微氣候資料驗證數值模擬結果，比較結果顯示本研究改良之SiB2模式由於在植物群內及地熱處理部分均做了相當幅度之修改，故能獲致較佳之模擬結果。此外本研究利用改良之數值模式評估水田區不同土地利用狀況對區域性微氣候之影響，模擬結果顯示水田在夏季具有涼化環境之功效，每公頃水稻田相當於約620台家用冷氣機之冷房效果，而水田在冬季則有暖化環境之功效，每公頃水稻田相當於約2,400台家用電暖爐之暖房效果。模擬結果亦顯示水田休耕時若能做為蓄水池使用，則調節區域性微氣候之效果更為顯著，其夏季冷房效果為水稻田之4倍，而冬季暖房效果為水稻田之2倍。
並列摘要
In this study we perform measurements and numerical simulations of paddy-field microclimate, and assess the effect of land-use pattern on the regional microclimate. To accurately simulate the paddy-field temperature and humidity variations, we use the theoretical framework of the simple biosphere model (SiB2) to modify the earlier plant-atmosphere-soil simulation model (PASSM). The electrical analog resistance formulation of heat and water fluxes is used, the heat fluxes in the surface-water and soil layers are incorporated, the more realistic leaf area distribution and inclination correction factor are used to evaluate the adsorbed solar radiation. Additionally, the periodic function of deep soil temperature variation is employed to evaluate the surface soil temperature. The microclimate data measured at the test paddy field are used to verify the model results. It is revealed that the modified SiB2 model gives better results than the PASSM model, primarily due to the improvements made in the computations of canopy and ground heat balance. The modified SiB2 model is further used to assess the effect of paddy-field land-use pattern on the regional microclimate. The simulation results indicate that in the summer the paddy fields function to achieve cooling of the environment, a one-hectare paddy field is equivalent to 620 family-type air conditioners, whereas in the winter they function to achieve warming of the environment, a one-hectare paddy field is equivalent to 2,400 family-type heaters. The simulation results also indicate that more significant cooling and warming effects can be achieved if the non-irrigated paddy fields are used as the storage ponds. The cooling effect of the storage pond is 4 times that of the paddy field, while the warming effect of the storage pond is twice that of the paddy field.