Solar-induced chlorophyll fluorescence detects photosynthesis variations and drought effects in tropical rubber plantation and natural deciduous forests
Solar-induced chlorophyll fluorescence detects photosynthesis variations and drought effects in tropical rubber plantation and natural deciduous forests
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DOI：
10.1016/j.agrformet.2023.109591
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发表时间：
2023-08
影响因子：
6.2
通讯作者：
Xueqian Wang;P. Blanken;J. Wood;Y. Nouvellon;P. Thaler;P. Kasemsap;A. Chidthaisong;P. Petchprayoon;C. Chayawat;J. Xiao;Xing Li
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文献类型：
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作者：
Xueqian Wang;P. Blanken;J. Wood;Y. Nouvellon;P. Thaler;P. Kasemsap;A. Chidthaisong;P. Petchprayoon;C. Chayawat;J. Xiao;Xing Li
摘要过去对全球碳平衡的评估显示，由于极端气候和土地利用变化的增加，特别是在东南亚大陆（MSEA），具有很高的不确定性。近年来，遥感叶绿素荧光（SIF）和植被近红外反射率（NIRv）在植被总初级生产力（GPP）动态研究中具有重要的应用价值。利用两个橡胶种植园和一个天然林的通量塔GPP，我们的研究评估了SIF和NIRv检测GPP和干旱胁迫这两个主要的土地利用在这个热带季风区的效用，和SIF，NIRv，GPP之间的潜在机制的联系路径分析的基础上。结果表明，OCO-2卫星的原始SIF及其衍生的两种高分辨率SIF产品（GOSIF和SIF <$oco 2 _ 005）在检测橡胶种植园GPP和干旱效应方面优于归一化植被指数（NDVI）和增强植被指数（EVI）。虽然年轻的天然林表现出较低的EVI和NIRv，它有相当的GPP的大小，橡胶种植园，这是捕获的SIF。通径分析表明，SIF与GPP的关系主要受NIRv的控制，NIRv代表了冠层结构效应，包括吸收和散射特性。在现场尺度分析，区域模式表明更高的一致性之间的SIF和NIRv比SIF和EVI的热带森林。SIF的量子效率对降水异常敏感，而其对光合作用的负面影响被干旱下高PAR所抵消。热带落叶林和种植园林都比万年青林更容易受到干旱的影响。我们强调使用NIRv和SIF监测冠层结构和光合作用，分别和更高分辨率的观测，以减少量化SIF-GPP关系的不确定性的需求。
Abstracts Past assessments of the global carbon balance have shown to have high uncertainty particularly in Mainland Southeast Asia (MSEA) owing to the increasing climate extremes and land use changes. Recently, remotely sensed solar-induced chlorophyll fluorescence (SIF) and near-infrared reflectance of vegetation (NIRv) have been found to have great potential to assess the dynamics of vegetation gross primary production (GPP). Using flux tower GPP from two rubber plantation and one natural forest sites, our study assessed the utility of SIF and NIRv to detect GPP and drought stress for these two major land uses in this tropical monsoon region, and the underlying mechanistic link among SIF, NIRv, and GPP based on path analysis. The results indicate that the native SIF from OCO-2 satellite and its two derived finer-resolution SIF products (ie, GOSIF and SIF¯ oco 2 _ 005) outperformed the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI) in detecting GPP and drought effects at the rubber plantation sites. Although the young natural forest exhibited much lower EVI and NIRv, it had comparable magnitude of GPP to the rubber plantations, which was captured by SIF. Path analysis shows that the SIF-GPP relationship was mainly controlled by NIRv, which represents the canopy structural effects including both the absorption and scattering traits. In line with site-scale analysis, the regional patterns indicated higher consistency between SIF and NIRv than betwen SIF and EVI for the tropical forests. The quantum yield of SIF (∅ F) was sensitive to precipitation anomaly, while its negative effect on photosynthesis was offset by high PAR under drought. Both tropical deciduous forest and plantation forest were more vulnerable to drought than evergreen forest. We highlight the usage of NIRv and SIF for monitoring canopy structure and photosynthesis, respectively, and the needs of higher-resolution observations to reduce the uncertainties in quantifying SIF-GPP relationships.