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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。研究利用该生态系统2003—2010年涡度相关和常规气象数据,阐述了生态系统呼吸对温度和土壤含水量的响应特征,对比分析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,呈现指数响应特征。但是,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起到明显的调控作用。参考温度下的生态系统呼吸(Rref)明显受土壤含水量的影响。生态系统年呼吸量为1 289.4±73.9 gC.m-2.a-1,两类模型的估算结果没有显著差异。但是在生态系统的季节变异上,两类模型估算存在显著差异,同时考虑温度与土壤含水量的模型更适合模拟遭受干旱胁迫的生态系统呼吸。
Changes in precipitation caused by global climate change affect the terrestrial ecosystem carbon budget. Carbon immobilized in terrestrial ecosystems returns to the atmosphere mainly through respiration, and temperature and moisture are important factors in regulating ecosystem respiration. ChinaFLUX Qianyanzhou mid-subtropical plantation flux station seasonal summer rains and rain caused by different seasonal drought for the study of temperature and moisture on the regulation of ecosystem respiration provided a natural test conditions. Using the vorticity-related and conventional meteorological data of the ecosystem from 2003 to 2010, the study described the response characteristics of ecosystem respiration to temperature and soil water content, and compared and analyzed the effect of ecosystem temperature on the ecosystem respiration The seasonal pattern and the effects of annual respiration. Studies have shown that the seasonal variations in ecosystem respiration are mainly controlled by soil temperature and exhibit exponential response characteristics. However, under drought stress, soil moisture plays a significant role in regulating seasonal variations in ecosystem respiration. Ecosystem respiration (Rref) at reference temperature is significantly affected by soil moisture content. The annual respiration rate of ecosystems was 1 289.4 ± 73.9 gC.m-2.a-1. There was no significant difference between the two models. However, there are significant differences between the two models in estimating seasonal variability of ecosystems. Simultaneously, the model considering temperature and soil water content is more suitable for simulating ecosystem respiration under drought stress.