Characterizing vegetation response to rainfall at multiple temporal scales in the Sahel-Sudano-Guinean region using transfer function analysis
Characterizing vegetation response to rainfall at multiple temporal scales in the Sahel-Sudano-Guinean region using transfer function analysis
复制标题
使用传递函数分析表征萨赫勒-苏达诺-几内亚地区植被对多个时间尺度降雨的响应
DOI：
10.1016/j.rse.2020.112108
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发表时间：
2021
影响因子：
13.5
通讯作者：
Yuan Xiaotian
中科院分区：
文献类型：
--
作者：
Zhou Jie;Jia Li;Menenti Massimo;van Hoek Mattijn;Lu Jing;Zheng Chaolei;Wu Hao;Yuan Xiaotian
降雨是陆地植被的关键驱动力。阐明植被对降雨的响应机制可以促进对预测降雨情景下生态系统预期变化的理解。除了一段时间内的降雨量，频率，持续时间和强度是重要的驱动生态系统过程。降雨强迫和植被响应的脉动性质特别适用于干旱和半干旱地区，并导致概念化的“脉冲储备”范式，我们用来解释我们在这项研究中提出的方法。我们介绍了在频域中的传递函数分析（TFA）的方法来捕捉植被降雨在多个时间尺度的响应。TFA方法确定的一致性，增益和相位来表征存在，强度和时滞，分别在不同的时间尺度上的植被对降雨的响应。具体地，相干性测量响应的存在，并且只有在显著响应的情况下，增益和相位值才是显著的并且对于进一步分析是有价值的。增益衡量植被生长波动和降雨波动之间关系的强度，而相位值（即时滞）衡量植被生长波动如何滞后（或导致）降雨波动。将TFA方法应用于萨赫勒-苏丹-几内亚地区（20°W ~ 60°E，0-25°E）34年（1982-2015）的NDVI 3g和CHIRPS降水数据集。萨赫勒地带的特点是在所有年内和年间时间尺度上对降雨量有显著的植被响应，而苏丹-几内亚地带则以年或6个月尺度上的显著响应为主。负相位滞后表明，降雨变化通常导致的NDVI变化的大部分地区和跨越时间尺度。然而，在热带雨林地区的部分地区观察到的正相位表明，植被指数的变化导致降雨量的变化，这可能是由强烈的植被-降雨反馈，通过蒸发蒸腾量的降水再循环。总之，这些结果表明，TFA方法是一个强大的工具，量化的植被降雨响应制度在一系列的时间尺度，概念化的“脉冲储备”的范例。揭示植被生长波动对降水强迫分量的响应可能会提高我们对萨赫勒-苏丹-几内亚地区过去几十年环境变化的理解。
Rainfall is a key driver of terrestrial vegetation. Clarifying the response mechanism of vegetation to rainfall can advance the understanding of expected changes in ecosystems under projected rainfall scenarios. Besides the rainfall amount over a period of time, the frequency, duration and intensity are of importance in driving ecosystem processes. The pulsating nature of rainfall forcing and of vegetation response applies particularly to arid and semi – arid regions and led to conceptualize the “pulse-reserve” paradigm, which we used to explain the approach we propose in this study. We introduce the Transfer Function Analysis (TFA) method in the frequency domain to capture the response of vegetation to rainfall at multiple temporal scales. The TFA method determines coherence, gain, and phase to characterize the existence, strength, and time-lag, respectively, of the vegetation response to rainfall at different temporal scales. Specifically, the coherence measures the existence of the response and only with a significant response are the gain and phase values significant and valuable for further analysis. The gain measures the strength of the relationship between fluctuations in vegetation growth and fluctuations in rainfall, while the phase value (i.e. the time-lag) measures how fluctuations in vegetation growth lag (or lead) fluctuations in rainfall. The TFA method was applied to the 34-years (1982–2015) NDVI3g and CHIRPS precipitation dataset in the Sahel-Sudano-Guinean region (20°W ~ 60°E, 0–25°E). The Sahelian zone was characterized by a significant vegetation response to rainfall across all inter- and intra- annual time-scales, while the Sudano-Guinean zone was dominated by significant response at annual or 6-month scales. The negative phase lag indicated that rainfall variation normally led NDVI change for most areas and across timescales. However, a positive phase observed in part of the tropical rainforest area indicated that NDVI changes led rainfall variations, which may be caused by the strong vegetation-rainfall feedback through recycling of precipitation by evapotranspiration. In summary, these results suggested that the TFA method is a powerful tool to quantify the vegetation-rainfall response regime across a range of timescales, as conceptualized by the “pulse-reserve” paradigm. Unraveling the response of fluctuations in vegetation growth to separate components of the forcing by precipitation might improve our understanding of environmental change in the past decades in the Sahel - Sudan - Guinean region.
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DOI：
10.1002/joc.1610
发表时间：
2008-07
期刊：
International Journal of Climatology
影响因子：
--
作者：
M.M.G. Loyarte;M. Menenti;A. Diblasi
通讯作者：
M.M.G. Loyarte;M. Menenti;A. Diblasi
影响因子：
4.8
作者：
NICHOLSON, SE;DAVENPORT, ML;MALO, AR
通讯作者：
MALO, AR
影响因子：
5.4
作者：
C. Gong;E. Eltahir
通讯作者：
C. Gong;E. Eltahir
影响因子：
2.7
作者：
A. Sher;D. Goldberg;A. Novoplansky
通讯作者：
A. Sher;D. Goldberg;A. Novoplansky
DOI：
10.1093/acrefore/9780190228620.013.553
发表时间：
2017-10
期刊：
--
影响因子：
--
作者：
R. Fensholt;C. Mbow;M. Brandt;K. Rasmussen
通讯作者：
R. Fensholt;C. Mbow;M. Brandt;K. Rasmussen