摘要:基于涡度相关系统，利用2004-2016年的涡度相关系统观测资料，做了青藏高原高寒湿地生长季总初级生产力（GPP）在不同时间尺度上对生长季有效积温（GDD）响应的研究。结果表明：高寒湿地生态系统在生长季的日GPP、GDD与月际GPP、GDD都表现为先增大后减小的单峰变化趋势，都在7月或8月达到峰值，在5月达到最小值。在整个生长季尺度上，GPP与GDD变异性较大，没有明显的变化趋势。2004-2016年整个生长季GPP与GDD的均值分别为（458.82±25.78）gC m^-2季^-1和（1060.89±84.07）℃。在日尺度、月尺度、生长季尺度上，GPP与GDD都呈极显著正相关关系（P < 0.01）。但是，通过比较生长季分别每个月GPP与GDD的关系发现，5、9月的GPP与GDD没有显著相关性（P > 0.05），而在7月相关性最为显著（P < 0.01）。整体上看，高寒湿地生态系统植被的总初级生产力与热量条件表现为正相关关系，由此说明在全球气候变暖的背景下，将会提高青藏高原高寒湿地生态系统植被的光合生产能力。



Abstract:Based on CO₂ fluxes measured with the eddy covariance technique, we analyzed the relationship between gross primary productivity (GPP) and growing season degree days (GDD) at different time scales over an alpine wetland in the Qinghai-Tibetan Plateau during the growing season from 2004 to 2016. The daily and monthly GPP and GDD in the growing season showed a single peak trend over the alpine wetland ecosystem. The maximum daily and monthly GPP and GDD values all occurred in July or August, while the minimum value occurred in May. However, GPP and GDD showed no obvious trends during the growing season. The mean values of seasonal GPP and GDD for the entire growing season from 2004 to 2016 were (458.82±25.78) gC m^-2 season^-1 and (1060.89±84.07) ℃.On the daily, monthly, and growing season scales, all GPP values positively correlated with GDD (P < 0.01). However, on comparing GPP and GDD in each month of the growing season, no significant correlation was found between GPP and GDD in May and September (P > 0.05), while the correlation was strongest (P < 0.01) in July. Overall, the GPP of the alpine wetland ecosystem indicated a positive reaction to the thermal condition, suggesting that the photosynthetic capacity of the wetland ecosystem in the Qinghai-Tibet Plateau could improve in the future under the effect of global warming.





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