【作者】 张舒；

【导师】 申双和； 温学发；

【作者基本信息】 南京信息工程大学 ， 应用气象学， 2012， 硕士

【摘要】 随着全球变暖的加快,对CO2通量的研究得到越来越多的关注。陆地生态系统是人类赖以生存的环境,与人类的生产生活密切相关,因此,陆地生态系统碳循环成为关注的焦点。森林生态系统作为陆地生态系统的主体,在缓解全球变化中占有重要的地位。在生态系统水平上,涡度相关技术(eddy covariance technique, EC)是评价植被与大气间净生态系统CO2交换量的主要手段,使碳水通量的长期观测成为可能,为研究生态系统呼吸提供平台。目前,基于统计方法估算生态系统呼吸得到了广泛的应用。主要分为基于夜间通量数据估算、基于白天数据估算以及应用同位素理论、相似理论、神经网络估算等。全球气候变化导致的降水格局改变影响陆地生态系统碳收支状况。陆地生态系统所固定的碳主要通过呼吸作用返回到大气中,而温度和水分是调节生态系统呼吸的重要因素。ChinaFLUX千烟洲中亚热带人工林通量站夏季雨热不同季而造成的季节性干旱为探讨温度和水分对生态系统呼吸的调控作用提供了天然的试验条件。本研究利用该生态系统2003～2010年涡度相关和常规气象数据,系统分析了生态系统呼吸对温度和土壤含水量的响应特征,探讨了只考虑温度与同时考虑温度和土壤含水量对生态系统呼吸的季节模式和年呼吸量的影响。研究表明：生态系统呼吸的季节变异主要受土壤温度的控制,均呈现指数响应特征。在干旱胁迫条件下,土壤含水量对生态系统呼吸的季节变异才起到明显的调控作用。只考虑温度影响条件下,年尺度的生态系统呼吸模型的参数参考温度下的生态系统呼吸明显受土壤含水量的影响；而同时考虑温度和土壤含水量影响条件下,参考温度下的生态系统呼吸则与土壤含水量无关。只考虑温度与同时考虑温度和土壤含水量的年尺度的生态系统呼吸模型估算的生态系统年呼吸量没有显著差异,该生态系统年呼吸量为1289.4±73.9gC m-2a-1。但是2003-2010年无论存在明显还是不明显的季节性干旱胁迫时期的生态系统呼吸的季节变异均存在显著的差异。更多还原

【Abstract】 With the tendency of global warming, more and more attention should be paied to CO2flux. Terrestrial ecosystem is the habitat of human beings, it is relevant with the production and life of people. Thus the study of carbon circulating in terrestrial ecosystem turns into the key point. As the main part of terrestrial ecosystem, forest plays an important role in controlling the climate change. Eddy covariance is a micrometeorological technique that allows a non-invasive measurement of the exchange of CO2between the atmosphere and a several hectare area of forest, shrubland, or grassland on the ecosystem scale and provides new platform to quantify and compare the magnitudes and dynamics of annual ecosystem carbon and water balance.At present, estimating of ecosystem respiration using statistics method is widely used, and can be classified in those that using only night-time data for the estimation of ecosystem respiration and those that exploiting daytime data using light-response curves, sometimes with both day and night-time data, for example stable carbon isotopes, correlation analysis and artificial neural network.The carbon balance has been affected by altered precipitation patterns caused by global climate changes. The carbon sequestrated by terrestrial ecosystems returns to the atmosphere mainly through respiration, of which temperature and water are two essential factors in regulating ecosystem respiration(Reco). Seasonal drought caused by the imbalance of heat and rain according to ChinaFLUX Qianyanzhou Subtropical plantations site provides natural experimental conditions to investigate the regulation of temperature and water on ecosystem respiration. Based on the Eddy covariance and conventional meteorological data collected from this ecosystem from2003to2010, this study analyzes the response of ecosystem respiration to temperature and soil water content, and explores the effects of temperature or both temperature and soil water content on ecosystem respiration seasonality and annual respiration. The study shows that the seasonal variations of ecosystem respiration is mainly controlled by soil temperature, and Reco is an exponential function of soil temperature. Only under drought condition can soil water content play a significant role in regulation. With only temperature taken into account, the ecosystem respiration rate at the reference temperature (Rref) was significantly affected by soil water content; while with only the conditions of temperature and soil taken into account, the ecosystem respiration under reference temperature was not affected by soil water content. There was no evident difference between considering temperature alone and both temperature and soil water content, the ecosystem respiration amount was1289.4±73.9gC m-2a-1. But the seasonal variations of ecosystem respiration had significant differences between2003and2010whether a seasonal drought existed or not.更多还原