Institute of Atmospheric Environment, China Meteorological Administration, Shenyang, People's Republic of China.
Shenyang Agricultural University, College of Agronomy, Shenyang, People's Republic of China.
PeerJ. 2022 Jun 8;10:e13549. doi: 10.7717/peerj.13549. eCollection 2022.
Evapotranspiration (ET) is a vital part of the global water cycle and is closely related to carbon sequestration. Analysing ET dynamics and their drivers would benefit for improving our understanding of the global water and carbon cycles. Using an eddy covariance (EC) approach, we analysed ET dynamics and their drivers in a temperate mixed forest over northeast China from 2016 to 2017. The results showed that 43.55% of our eddy covariance data passed the quality control. In addition, the energy balance ratio was 0.62, indicating that measurements were reliable. The measured ET showed clear single peak patterns with seasonal and diurnal variations. The daily ET ranged from 0 to 7.75 mm d and the hourly ET ranged from 0 to 0.28 mm h. The ranges of hourly ET floated from 0 to 0.05 mm h at non-growing season (November to April) while ranged from 0 to 0.28 mm h at active growing season (May to October). The diurnal ET dynamics during the non-growing season were driven by air temperature ( ) but were governed by global radiation ( ) during the active growing season. Leaf area index (LAI) comprehensively reflected the variations of and , and was found to be the primary factor shaping the seasonal dynamics of ET. The annual ET rates were 501.91 ± 5.30 mm year and 554.60 ± 11.24 mm year for 2016 and 2017, respectively. Therefore, energy supply, represented by and , governed ET dynamics in our temperate mixed forest, while variables representing the energy supply affecting ET dynamics differed among seasons and time scales. ET dynamics indicated that a temperate mixed forest is important to the global water cycle. Our results improved our understanding of ET dynamics in the studied region.
蒸散量（ET）是全球水循环的重要组成部分，与碳固存密切相关。分析 ET 动态及其驱动因素将有助于提高我们对全球水碳循环的认识。本研究采用涡度相关（EC）方法，分析了中国东北温带混合林 2016 年至 2017 年期间的 ET 动态及其驱动因素。结果表明，43.55%的涡度相关数据通过了质量控制。此外，能量平衡比为 0.62，表明测量结果可靠。测量得到的 ET 表现出明显的单峰模式，具有季节性和日变化。日蒸散量的范围为 0 至 7.75mm d，小时蒸散量的范围为 0 至 0.28mm h。非生长季（11 月至 4 月）的小时蒸散量范围为 0 至 0.05mm h，而活跃生长季（5 月至 10 月）的小时蒸散量范围为 0 至 0.28mm h。非生长季的日蒸散量动态受空气温度（）驱动，但在活跃生长季受总辐射（）控制。叶面积指数（LAI）综合反映了和的变化，是塑造 ET 季节性动态的主要因素。2016 年和 2017 年的年蒸散量分别为 501.91±5.30mm 年和 554.60±11.24mm 年。因此，以和表示的能量供应控制了我们温带混合林的 ET 动态，而代表影响 ET 动态的能量供应的变量在不同季节和时间尺度上有所不同。ET 动态表明，温带混合林对全球水循环具有重要意义。本研究结果提高了我们对研究区域 ET 动态的认识。
