纳木错高寒湿地自然水位梯度上的CH4和CO2通量研究

项目名称： 纳木错高寒湿地自然水位梯度上的CH4和CO2通量研究

项目编号： No.41305122

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 天文学、地球科学

项目作者： 魏达

作者单位： 中国科学院青藏高原研究所

项目金额： 25万元

中文摘要： 湿地是全球最大的CH4排放源，也是重要的CO2源汇功能区。我国青藏高原水源丰富、地形起伏大、冻土发育水分不易下渗，其高寒湿地面积约占我国天然湿地的1/3。但目前对高寒湿地CH4和CO2通量估算不确定性较大，尤其是对CH4排放存在潜在高估。同时，在气候变暖引起的蒸发增强和冰川融化的背景下，由此导致的水位变化可能影响着高寒湿地的CH4和CO2通量，这进一步加剧了通量的不确定性。本项目拟选取位于青藏高原腹地纳木错湖滨的藏北嵩草-苔草高寒湿地，进行自然水位梯度上的全年观测，定量CH4和CO2通量，减小二者通量估算中的不确定性尤其是CH4高估问题；并进一步指示长期水位变化对CH4和CO2通量的影响趋势和程度；探索性开展机理实验，初步理解水位变化对CH4影响的机理机制。本项目旨在摸清典型高寒湿地主要温室气体源汇的"家底"，并明确和理解高寒湿地生物地球化学循环对气候变化的反馈过程。

中文关键词： 青藏高原；高寒湿地；甲烷；气候变化；

英文摘要： Wetlands are the largest individual CH4 sources across the world, as well as vital sinks/sources for CO2. For the reason of huge water storage, complex topographic relief and vast permofrost distribution, there are widespread wetlands on the Tibetan Plateau, which account for 1/3 of China's natural wetlands.However, large uncertainties for estimation of CH4 and CO2 exchanges, especially potential over-estimation of CH4 emissions,are still remained due to scarce observations there. Furthermore, the alpine wetlands are affected by water level changes and thus enlarged uncertainties, caused by both enhanced evaporation and glacier melting under the fast warming climate in recent decades. Therefore,measurements of CH4 and CO2 fluxes are proposed to carry out in a typical alpine wetland on the hiterland of the Tibetan Plateau, dominated by Kobresia littledalei and Carex moocroftii. It's sheduled to investigate the variations of CH4 and CO2 fluxes across a gradient of water levels in situ, to predict future influences of water level shifts on CH4 and CO2 exchanges.Preliminary researches on CH4 production, transportation and oxidation are also about to conducted along the gradient, to understand the mechanisms of CH4 fluxes changes. In summary, this proposal is dedicated to quatify the CH4 and CO2 exchanges in a typica

英文关键词： Tibetan Plateau；Alpine wetlands；Methane；Climate change；