J Plant Ecol ›› 2022, Vol. 15 ›› Issue (5): 911-920 .DOI: 10.1093/jpe/rtac007

• Research Articles • Previous Articles     Next Articles

Fisher discriminant analysis method applied in drought detection: an instance in an alpine meadow ecosystem

Tao Zhang1, Ximeng Ji1, Yuanyuan Tang1, Mingjie Xu1,*, Yangjian Zhang2,3,4, *, Guang Zhao2, Ning Chen5, Juntao Zhu2,3 and Yongtao He2,4   

  1. 1 College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China, 2 Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China, 3 Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China, 4 College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China, 5 Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China

    *Corresponding author. E-mail: xumj@syau.edu.cn (M.X.); zhangyj@igsnrr.ac.cn (Y.Z.)
  • Received:2021-07-12 Revised:2021-08-26 Accepted:2021-11-22 Online:2022-01-13 Published:2022-09-01


Fisher discriminant analysis can comprehensively take multiple factors into consideration and effectively conduct separations between two classes. If it can be used to detect the occurrences of drought, drought can be detected more effectively and accurately. Based on 9-year carbon flux and corresponding meteorological data, soil water content (SWC) and vapor pressure deficit (VPD) were selected as the discriminant factors. Drought occurrences were detected by applying the Fisher discriminant analysis method in an alpine ecosystem in Tibet. Fisher discriminant analysis was successfully applied to detect drought occurrence in an alpine meadow ecosystem. The soil water deficit and atmospheric water deficit were comprehensively taken into consideration. Consequently, this method could detect the onset and end date of droughts more accurately and reasonably. Based on the characteristics of drought and non-drought samples, the discriminant equation was constructed as y = 24.46SWC − 4.60VPD. When y > 1, the days were distributed above the critical line. In addition, when y was greater than one for more than 10 days, it was labeled as one drought event. If the interval between two drought processes was less than 2 days, it was considered one drought event. With increasing the study period and continued accumulation of observation data, the discriminant equation could be further optimized in the future, resulting in more accurate drought detection.

Key words: soil water, VPD, GPP, alpine meadow, Tibetan Plateau

Fisher判别法可综合考虑事物的多重属性特征,进而分辨事物类型。若能将其应用于对干旱的识别,或将成为一种准确而有效的干旱识别方法。本研究以高寒草甸生态系统为研究对象,基于9年碳通量和小气候观测数据,以土壤含水量(soil water content, SWC)和饱和水汽压差(vapor pressure deficit, VPD)作为判别因子,利用Fisher判别法识别干旱。Fisher判别法可用于对高寒草甸生态系统干旱的识别。因其综合考虑了土壤水分匮缺和大气水分匮缺,故可以更合理准确地判断干旱的开始和结束时间。基于干旱样本和非干旱样本的特征,构建判别方程为:y = 24.46SWC − 4.60VPD。当y > 1时,样本点位于临界线上方,若持续10天以上,则判定为发生干旱。两次干旱过程间隔2天以内,可认为是一次干旱过程。随着研究年限的增加和观测数据的积累,该临界线方程尚有优化空间,其对干旱识别的准确度可进一步提高。

关键词: 土壤水分, 饱和水汽压差(VPD), 总初级生产量(GPP), 高寒草甸, 青藏高原