Observation of the CO2/CH4 fluxes and emissions establishment - A Case Study of the Chiku wetland in Taiwan

本研究在科技部「沿海濕地碳匯的保育與管理-以七股海岸地區為例-七股沿岸生態系二氧化碳、甲烷通量之觀測及碳匯動態模式之發展 (3/3)」 (NSC103-2627-B005-004)支持下，於臺灣七股濕地以渦流協變系統 (Eddy Covariance system, EC)進行二氧化碳及甲烷通量之觀測，並藉由溫度係數 (Temperature coefficient, Q10)建立呼吸作用模型，以及推估乾沉降模型之地表阻抗參數，估算臺灣七股濕地二氧化碳及甲烷排放量。 在2014年，開始於魚塭、鹽田與潟湖等不同地貌進行不同季節之二氧化碳與甲烷通量觀測。觀測結果顯示，二氧化碳通量在日間因生物行光合作用約有0.8 mg m-2 s-1碳匯 (sink)情況，夜間則是生物呼吸作用影響約0.4 mg m-2 s-1源 (source)情況；甲烷通量在日間因甲烷氧化作用旺盛約有1.5 μg m-2 s-1碳匯 (sink)情況，夜間則是受產甲烷作用影響約1.5 μg m-2 s-1源 (source)情況。二氧化碳呼吸作用通量和夜間甲烷通量皆與大氣溫度呈現指數下降，而二氧化碳光合作用通量及甲烷日間通量存在最適溫度範圍且受季節不同影響。推估之魚塭葉面積指數 (LAI)為0.033，鹽田為0.056，潟湖為0.031。二氧化碳及甲烷在台灣七股濕地皆為碳匯 (sink)情況，總排放量分別約為-271 Gg CO2 yr-1及-372 Mg CH4 yr-1。臺灣七股濕地為一具有碳匯能力之地貌，了解其在減緩臺灣溫室氣體排放上具有一定的貢獻。The study was supported by the Ministry of Science and Technology program “Conservation and management of carbon sinks in coastal wetlands - a case study in Chiku coastal area (3/3)” (NSC103-2627- B005-004). The purpose of this study is observation of carbon dioxide and methane flux in Taiwan Chiku wetland by eddy covariance system (EC), and to establish respiration model by the temperature coefficient (Q10), and to estimates surface resistance of dry deposition model to establish Taiwan Chiku wetland carbon dioxide and methane emissions. In 2014, carbon dioxide and methane flux begin to be observed in different seasons. The experimental sites were located at fish-pond, salt pans and lagoons in Taiwan Chiku wetlands. The results showed that carbon dioxide fluxes were 0.8 mg m-2 s-1 (sink) due to photosynthesis of biological during the day and carbon dioxide fluxes were 0.4 mg m-2 s-1 (source) due to respiration of biological during the night. The methane fluxes were 1.5 μg m-2 s-1 (sink) due to methane oxidation strong during the day and methane fluxes were 1.5 μg m-2 s-1 (source) due to methanogenesis during the night. Nighttime respiration fluxes and methane flux were all exponential decline with air temperature. Daytime photosynthesis fluxes and methane flux existed the optimum temperature range in different seasonal. Estimate the leaf area index (LAI) were 0.033 at fish-pond, 0.056 at salt pans and 0.031 at lagoons. Carbon dioxide and methane were all sinks in Taiwan Chiku wetlands, the total emissions were -271 Gg CO2 yr-1 and -372 Mg CH4 yr-1. Taiwan Chiku wetlands having carbon sink capacity of the landscape on the mitigation of greenhouse gas emissions in Taiwan have some contribution.摘要 I Abstract II 目錄 III 圖目錄 V 表目錄 VII 第一章 前言 1 1.1 研究緣起 1 1.2 研究目的 3 第二章 文獻回顧 4 2.1 濕地二氧化碳觀測 4 2.2 濕地甲烷通量觀測 6 第三章 研究方法與原理 9 3.1 研究架構 9 3.2 實驗地點與時間 10 3.3 實驗設備 12 3.3.1 EC系統 12 3.3.2 微氣象觀測系統 12 3.4 EC系統原理 14 3.5 誤差校正 15 3.5.1 二維座標旋轉 15 3.5.2 WPL校正 16 3.6 呼吸作用通量 (Fr)及光合作用通量 (Fp) 18 3.7 乾沉降三層阻尼機制 20 3.7.1 氣動阻抗 (ra) 20 3.7.2 邊界層傳輸阻抗 (rb) 21 3.7.3 地表阻抗 (rc) 21 3.8 乾沉降模型建立 24 3.9 推估排放量 24 第四章 結果與討論 25 4.1 魚塭觀測 25 4.1.1 氣象因子 25 4.1.2 通量及濃度時間序列 26 4.2 鹽田觀測 31 4.2.1 氣象因子 31 4.2.2 通量及濃度時間序列 32 4.3 潟湖觀測 37 4.3.1 氣象因子 37 4.3.2 通量及濃度時間序列 38 4.4 呼吸作用 (Fr)及光合作用 (Fp) 42 4.4.1 呼吸作用 (Fr)與大氣溫度 (Ta) 42 4.4.2 光合作用 (Fp)與大氣溫度 (Ta) 44 4.4.3 光合作用 (Fp)與太陽短波輻射 (Rs) 46 4.4.4 最適溫度探討 48 4.5 乾沉降模型建立 49 4.6 排放量推估 51 第五章 結論與建議 53 5.1 結論 53 5.2 建議 54 第六章 參考文獻 55 附錄 6