J Plant Ecol ›› 2024, Vol. 17 ›› Issue (1): rtad033.DOI: 10.1093/jpe/rtad033

• Research Article •    

Observed decreasing trend in pan evaporation in a tropical rainforest region during 1959-2021

Yan Jin1, Ying Zhang2, Xin Yang1, Mou Zhang1, Xin-Bo Guo1, Yun Deng3,4, Yue-Hua Hu3, Hua-Zheng Lu3,4, Zheng-Hong Tan1,*   

  1. 1School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China;
    2International Center for Climate and Environment Sciences, Institution of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;
    3CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Menglun 666303, China;
    4Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Menglun 666303, China
  • Received:2023-05-23 Revised:2023-07-04 Accepted:2023-09-13 Online:2023-09-30 Published:2024-02-01
  • Contact: E-mail: tan@ynu.edu.cn


Abstract: Pan evaporation (Epan) is a critical measure of the atmospheric evaporation demand. Analyzing meteorological data from the Tropical Rainforest Comprehensive Meteorological Observation Field in the Xishuangbanna Tropical Botanical Garden (XTBG Meteorological Observing Station) based on physical models is helpful to improve our understanding of the state of the hydrological cycle in the Xishuangbanna tropical rainforest region. In this study, we investigated the long-term trend in Epan using the observation data from 1959 to 2021. Moreover, correlation analyses of Epan were performed, such as trend test, assessment of periodic properties and abrupt change analysis. Then, D20 Epan data and related meteorological data from 1979 to 2008 were used to drive Penman‒Monteith and PenPan models for simulating Epan. The partial derivative attribution method was used to analyze the dominant factors affecting Epan. The results showed that Epan exhibits obvious periodic changes, the 19a is the first primary period. In addition, there was a clear ‘evaporation paradox’ phenomenon in Xishuangbanna. Epan showed a decreasing trend during both 1959-2008 and 2009-2018, and the decreasing trend reached a significant level with a rate of -3.404 mm·a-2 during 1959-2008. Through comparative analysis, the PenPan model was considered more suitable for simulating Epan in Xishuangbanna. In order to identify the main meteorological factors influencing Epan, complete data from the D20 pan monitoring period, namely, 1979-2008, were selected for attribution calculations. The variations in the net radiation and saturated vapor pressure deficit are the main triggers that explain the ‘evaporation paradox’ phenomenon in Xishuangbanna.

Key words: pan evaporation, evaporation paradox, PenPan model, partial derivative method, driving factors

1959-2021年间热带雨林区域的蒸发皿蒸发量呈下降趋势蒸发皿蒸发量(Epan)是衡量大气蒸发需求的重要指标。基于物理模型对西双版纳热带植物园中热带雨林综合气象观测场(XTBG气象站)的气象资料进行分析,有助于提高我们对西双版纳热带雨林区域水文循环状况的认识。本文利用1959-2021年的观测资料,研究了Epan的长期变化趋势,并进行了趋势检验、周期性评价和突变分析等相关分析。基于1979-2008年D20 Epan数据和相关气象资料,利用Penman-Monteith和PenPan模型对Epan进行模拟,采用偏微分归因法分析了影响Epan的主导因素。研究结果表明,Epan具有明显的周期变化,19 a为第一主周期。而且,西双版纳地区存在明显的‘蒸发悖论’现象。Epan在1959-2008年和2009-2018年均呈下降趋势,其中1959-2008年下降幅度达到显著水平,为-3.404 mm  a-2。通过对比分析,认为PenPan模型更适合用于模拟西双版纳地区的Epan。为了确定影响Epan的主要气象因子,选取了D20蒸发皿完整监测时期的数据(1979-2008)进行归因计算。太阳净辐射和饱和蒸汽压差的减小趋势可以有效抵消气温上升对Epan的促进作用。因此,净辐射和饱和蒸汽压差的变化是西双版纳‘蒸发悖论’现象的主要触发因素。

关键词: 蒸发皿蒸发量, 蒸发悖论, PenPan模型, 偏微分归因法, 驱动因素