Wang Yuan, Zhang Na, Yu Gui-rui
College of Resource and Environment, Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
Ying Yong Sheng Tai Xue Bao. 2010 Jul;21(7):1656-66.
By using modified carbon-water cycle model EPPML (ecosystem productivity process model for landscape), the carbon absorption and respiration in Qianyanzhou artificial masson pine forest ecosystem in 2003 and 2004 were simulated, and the sensitivity of the model parameters was analyzed. The results showed that EPPML could effectively simulate the carbon cycle process of this ecosystem. The simulated annual values and the seasonal variations of gross primary productivity (GPP), net ecosystem productivity (NEP), and ecosystem respiration (Re) not only fitted well with the measured data, but also reflected the major impacts of extreme weather on carbon flows. The artificial masson pine forest ecosystem in Qianyanzhou was a strong carbon sink in both 2003 and 2004. Due to the coupling of high temperature and severe drought in the growth season in 2003, the carbon absorption in 2003 was lower than that in 2004. The annual NEP in 2003 and 2004 was 481.8 and 516.6 g C x m(-2) x a(-1), respectively. The key climatic factors giving important impacts on the seasonal variations of carbon cycle were solar radiation during early growth season, drought during peak growth season, and precipitation during post-peak growth season. Autotrophic respiration (Ra) and net primary productivity (NPP) had the similar seasonal variations. Soil heterotrophic respiration (Rh) was mainly affected by soil temperature at yearly scale, and by soil water content at monthly scale. During wet growth season, the higher the soil water content, the lower the Rh was; during dry growth season, the higher the precipitation during the earlier two months, the higher the Rh was. The maximum RuBP carboxylation rate at 25 degrees C (Vm25), specific leaf area (SLA), maximum leaf nitrogen content (LNm), average leaf nitrogen content (LN), and conversion coefficient of biomass to carbon (C/B) had the greatest influence on annual NEP. Different carbon cycle process could have different responses to sensitive parameters. For example, the increase of Vm25 and LN could effectively promote carbon absorption and respiration, the decrease of LN/LNm could decrease the carbon absorption and respiration, and, the increase of SLA and C/B could promote carbon absorption but inhibit soil respiration. However, the most sensitive parameters derived from annual carbon fluxes were not completely the same as those derived from growth season or non-growth season carbon fluxes.
利用改进的碳 - 水循环模型EPPML（景观生态系统生产力过程模型），模拟了2003年和2004年千烟洲人工马尾松林生态系统的碳吸收和呼吸作用，并分析了模型参数的敏感性。结果表明，EPPML能够有效模拟该生态系统的碳循环过程。模拟的年值以及总初级生产力（GPP）、生态系统净生产力（NEP）和生态系统呼吸（Re）的季节变化不仅与实测数据拟合良好，而且反映了极端天气对碳流动的主要影响。千烟洲人工马尾松林生态系统在2003年和2004年都是强大的碳汇。由于2003年生长季节高温与严重干旱的耦合，2003年的碳吸收低于2004年。2003年和2004年的年NEP分别为481.8和516.6 g C x m(-2) x a(-1)。对碳循环季节变化产生重要影响的关键气候因素是生长初期的太阳辐射、生长盛期的干旱以及生长盛期后期的降水。自养呼吸（Ra）和净初级生产力（NPP）具有相似的季节变化。土壤异养呼吸（Rh）在年尺度上主要受土壤温度影响，在月尺度上受土壤含水量影响。在湿润生长季节，土壤含水量越高，Rh越低；在干旱生长季节，如果前两个月降水量越高，Rh越高。25℃时最大RuBP羧化速率（Vm25）、比叶面积（SLA）、最大叶片氮含量（LNm）、平均叶片氮含量（LN）以及生物量到碳的转换系数（C/B）对年NEP影响最大。不同的碳循环过程对敏感参数可能有不同的响应。例如，Vm25和LN的增加能有效促进碳吸收和呼吸，LN/LNm的降低会减少碳吸收和呼吸，SLA和C/B的增加能促进碳吸收但抑制土壤呼吸。然而，从年碳通量得出的最敏感参数与从生长季节或非生长季节碳通量得出的最敏感参数并不完全相同。
