[关键词]
[摘要]
为了解寒区湿地实际蒸散发( ETa ) 过程, 有效利用水资源, 基于哈尔滨金河湾湿地 2015 年 8 月- 2016 年 7 月 涡度相关系统通量观测数据, 分析了不同时间尺度下 ETa 变化规律及影响因素。研究期间年 ETa 为 660 mm, 日最高值达 8.1 mm/d, 夏季( 3.4 mm/d) 最高, 春季(2.3 mm/d) 、秋季( 1.4 mm/d) 次之, 冬季( 0.1 mm/d) 偏低且变化平稳。5 月生长期作物系数( Kc) 由 0.95 增加到 1.18 左右, 6 月- 8 月中旬稳定期 Kc 在1.05~ 1.18 之间, 8 月下旬- 9 月枯萎期 Kc 由 1.05 减小到 0.85 左右。影响 ETa 的主要气象因素为净辐射和饱和水汽压差。不同时间尺度下 ETa 与气象因子相关性略有不同: 净辐射和水汽压差与 ETa 的相关性在两个尺度上均很显著, 但 30 min 尺度净辐射与 ETa 的相关性更高。温度与 ETa 的相关性在两个尺度上基本一致, 高温促进 ETa 蒸散发而低温抑制ETa 蒸散发。日尺度上空气湿度与 ETa 在秋、冬季相关性明显, 30 min 尺度上春、冬季相关性明显。风速与 ETa 仅在 30 min 尺度上夏、秋季有一定的相关性。
[Key word]
[Abstract]
In order to understand the actual evapotranspiration ( ETa ) process in cold wetland and to make effective management of water resources, we analyzed the variation of ETa in Harbin Jinhewan wetland and its influencing factors under different time scales based on the measured dat a of eddy covariance system from August 2015 to July 2016. The annual ETa was 660mm during the study period, and the maximum daily ETa was up to 8. 1mm/ d. The ETa was the highest in summer ( 3.4 mm/ d) , second highest in spring ( 2.3 mm/ d) and autumn ( 1.4 mm/ d) , and was the lowest and stable in winter ( 0.1 mm/ d) . The crop coefficient(Kc) increased from 0.95 to about 1.18 in May ( plantg rowing period) .The Kc was between 1.05-1. 18 from June to the middle of August (plant stabilizing period), and it decreased from 1.05 to 0.85 during late August to September (plant withering period) . The main meteorological factors affecting the ETa were net radiation and vapor pressure deficit. The correlations between ETa and meteorological factors were different at differenttime scales. The correlations of net radiation and water vaporpr essure deficit with ETa were significant at both scales, but net radiation was more correlated to ETa at the 30min scale. The correlation between temperature and ETa was basically consistent at both scales. High temperature would promote ETa and low temperature would suppress ETa. At the daily scale, the correlation between air humidity and ETa was obvious in autumn and winter; at the 30 min scale, the correlation was o bvious in spring and winter. The correlation between wind speed and ETa was only obvio us in summer and autumn at the 30 min scale.
[中图分类号]
[基金项目]
国家自然科学基金( 51379079; 51609084)