Measurement and modeling of rainfall interception by two differently aged secondary forests in upland eastern Madagascar
Measurement and modeling of rainfall interception by two differently aged secondary forests in upland eastern Madagascar
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DOI：
10.1016/j.jhydrol.2016.10.032
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发表时间：
2017-02
影响因子：
6.4
通讯作者：
C. Ghimire;L. A. Bruijnzeel;M. Lubczynski;M. Ravelona;B. Zwartendijk;H. V. Meerveld
中科院分区：
文献类型：
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作者：
C. Ghimire;L. A. Bruijnzeel;M. Lubczynski;M. Ravelona;B. Zwartendijk;H. V. Meerveld
在许多热带地区，次生林占据的面积比古老的热带雨林大，但人们对它们的水文功能仍然知之甚少。特别是，人们对这些可能大力再生的森林中蒸散的各种成分知之甚少。本文比较了马达加斯加东部低山雨林带半成熟林(约200a生)和幼林(5a~7a龄)林冠截留损失(I)的实测值和模型。两个森林的总降雨量(P)、穿透降雨量(Tf)和树干径流(Sf)被测量了一年(2014年10月至2015年9月)，并修正了Gash等人的分析模型。(1995)第一次在热带次生林环境中进行了测试。半成熟林总Tf、SF和衍生量分别占入侵量的71.0%、1.7%和27.3%。幼林的对应值分别为75.8%、6.2%和18.0%。幼林的高SF反映了优势种(Psiadia Altissima)的树枝强烈向上推进的习性，这有利于漏斗状的OFP。半成熟森林的I值与其他地方报告的古老热带低山雨林的I值相似，但年轻森林的I值高于报告的类似年龄的热带低地森林的I值。这些发现在很大程度上是由当时的低降雨强度和经常发生的小降雨事件造成的。修正后的分析模型能够准确地再现两个站点的实测累积量，并成功地捕捉到与降雨强度季节变化有关的变异性，只要使用基于Tf的平均湿冠蒸发速率值而不是用Penman-Monteith方程得出的值。
Secondary forests occupy a larger area than old-growth rain forests in many tropical regions but their hydrological functioning is still poorly understood. In particular, little is known about the various components of evapotranspiration in these possibly vigorously regenerating forests. This paper reports on a comparison of measured and modeled canopy interception losses (I) from a semi-mature (ca. 20 years) and a young (5–7 years) secondary forest in the lower montane rain forest zone of eastern Madagascar. Measurements of gross rainfall (P), throughfall (Tf), and stemflow (Sf) were made in both forests for one year (October 2014–September 2015) and the revised analytical model of Gash et al. (1995) was tested for the first time in a tropical secondary forest setting. Overall measured Tf, Sf and derivedIin the semi-mature forest were 71.0%, 1.7% and 27.3% of incidentP, respectively. Corresponding values for the young forest were 75.8%, 6.2% and 18.0%. The high Sf for the young forest reflects the strongly upward thrusting habit of the branches of the dominant species (Psiadia altissima), which favours funneling ofP. The value ofIfor the semi-mature forest is similar to values reported for old-growth tropical lower montane rain forests elsewhere butIfor the younger forest is higher than reported for similarly aged tropical lowland forests. These findings can be explained largely by the prevailing low rainfall intensities and the frequent occurrence of small rainfall events. The revised analytical model was able to reproduce measured cumulativeIat the two sites accurately and succeeded in capturing the variability inIassociated with the seasonal variability in rainfall intensity, provided that Tf-based values for the average wet-canopy evaporation rates were used instead of values derived with the Penman-Monteith equation.