植物生态学报 ›› 2022, Vol. 46 ›› Issue (8): 890-903.DOI: 10.17521/cjpe.2021.0363

• 研究论文 • 上一篇    下一篇

重庆缙云山针阔混交林水汽通量特征及其影响因子

冯印成1, 王云琦1,*(), 王玉杰1, 王凯1, 王松年1, 王杰帅2   

  1. 1北京林业大学重庆缙云山三峡库区森林生态系统定位观测研究站, 水土保持学院, 北京 100083
    2苏州高新区林业站, 江苏苏州 215011
  • 收稿日期:2021-10-12 接受日期:2022-03-21 出版日期:2022-08-20 发布日期:2022-04-22
  • 通讯作者: 王云琦
  • 作者简介:*(wangyunqi@bjfu.edu.cn)

Water vapor fluxes and their relationship with environmental factors in a conifer-broadleaf mixed forest ecosystem in Jinyun Mountain, Chongqing, China

FENG Yin-Cheng1, WANG Yun-Qi1,*(), WANG Yu-Jie1, WANG Kai1, WANG Song-Nian1, WANG Jie-Shuai2   

  1. 1Chongqing Jinyun Mountain Three Gorges Reservoir Area Forest Ecosystem Positioning Observation and Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
    2Forestry Station of Suzhou High Tech Zone, Suzhou, Jiangsu 215011, China
  • Received:2021-10-12 Accepted:2022-03-21 Online:2022-08-20 Published:2022-04-22
  • Contact: WANG Yun-Qi

摘要:

利用涡度相关技术于2019年9月-2020年8月在重庆缙云山针阔混交林生态系统观测了水汽通量和其他环境要素。基于观测数据, 分析了水汽通量特征及其与环境因子的关系。结果表明: (1)针阔混交林生态系统能量闭合率为0.77, 且通量足迹高贡献区域所处方向与风玫瑰图的全年主风方向(东北风向)一致, 累计通量贡献区变异系数比较小, 证明涡度相关技术在研究区适应性较好, 数据可靠。(2)缙云山针阔混交林的全年水汽通量基本为正值, 月平均日变化范围为-0.001-6.623 mmol·m-2·s-1, 说明研究区为水汽源。水汽通量月平均日变化和季节变化均为单峰趋势。夏季水汽通量平均值最大(4.620 mmol·m-2·s-1), 变化趋势强; 冬季水汽通量值最低(2.077 mmol·m-2·s-1), 变化趋势弱。(3)该地区全年蒸散总量(792.40 mm)占降水总量(1 489.18 mm)的53.12%, 夏季的蒸散量(325.53 mm)和降水量(680.52 mm)最高, 分别占到全年蒸散量和降水量的41%和46%。缙云山针阔混交林生态系统站点与其他地区不同生态系统站点对比, 得出全年蒸散量为湿地>森林>农田。(4)净辐射、气温、饱和水汽压差和风速对水汽通量的影响在各季节均显著, 净辐射、气温和饱和水汽压差与水汽通量呈正相关关系, R2最大分别为0.85、0.53和0.60, 风速与水汽通量呈负相关关系, R2为0.61, 均是夏季的相关性最高, 其中净辐射和气温是影响水汽通量的最主要因子。

关键词: 针阔混交林, 水汽通量, 涡度相关, 蒸散, 净辐射

Abstract:

Aims This study aimed to examine the practicability of eddy covariance method in a conifer-broadleaf mixed forest ecosystem in Jinyun Mountain of Chongqing, China, and to analyze the dynamics of water vapor flux in this forest ecosystem. Meanwhile, the main environmental factors that influence water vapor flux was also discussed. Our results may provide a case for such study in forest water vapor budget.

Methods The eddy covariance method was used to continuously observe the vapor fluxes and meteorological factors from September 2019 to August 2020 in a conifer-broadleaf mixed forest. The original data of water vapor flux was corrected and interpolated by Eddy Pro software. We used these data to analyze the energy closure and variation of water vapor fluxes, and as well as environmental factors.

Important findings (1) The energy closure rate in our study forest is 0.77. The direction of the high contribution area of flux footprints in such forest is similar to the annual main wind direction (northeast), indicating that the method of vorticity related technology is practicable and reliable in this kind of forest. (2) In our study forest, the annual water vapor flux is over zero, and the monthly average daily variation is -0.001-6.623 mmol·m-2·s-1, suggesting that this forest is a source of water vapor in study area. There is a single peak trends for monthly average daily variation and seasonal variation of water vapor fluxes. By contrast, the average value of water vapor fluxes is the highest (4.620 mmol·m-2·s-1) in summer with strong fluctuations, and the lowest (2.077 mmol·m-2·s-1) in winter with weak fluctuations. (3) The total annual evapotranspiration (792.40 mm) in this forest accounts for 53.12% of the total precipitation (1 489.18 mm), and the summer evapotranspiration (325.53 mm) and precipitation (680.52 mm) are the highest, accounting for the annual evapotranspiration and precipitation respectively 41% and 46%. Compared with other ecosystem sites, we found that total annual evapotranspiration was less in our study forest than in wetland, but more than in farmland and grassland. (4) The water vapor flux was positively correlated with net radiation, air temperature and vapor pressure deficit. Such correlations (R2) were the highest in summer, and reached to 0.85, 0.53 and 0.60, respectively. Conversely, the water vapor flux was negatively correlated with wind speed, and the R2 equal to 0.61 in the summer. It seems likely that net radiation and air temperature are the main drivers in water circulating at our study forest.

Key words: conifer-broadleaf mixed forest, water vapor flux, eddy correlation, evapotranspiration, net radiation