系統(tǒng)功能

采用熱擴(kuò)散技術(shù)測(cè)量植物莖干莖流速度，特別適用于莖干較粗的樹(shù)木和高大植物。若配合其它傳感器使用，可測(cè)量環(huán)境因子（空氣溫濕度，光合有效輻射、土壤溫濕度等）影響下的植物莖流。

工作原理

利用Granier熱擴(kuò)散傳感器（TDP）原理，把2根熱電偶探針直接插入邊材，上面的探針包含1個(gè)電加熱器，下面的探針作為參照，測(cè)量加熱探針和參照探針之間的溫差dT。根據(jù)dT和零莖流時(shí)的dTm，應(yīng)用Granier模型，可以直接得到每個(gè)時(shí)刻的莖流速率，再根據(jù)邊材面積求出莖流通量。

對(duì)于郁閉冠層下長(zhǎng)勢(shì)一致的樹(shù)木，每棵樹(shù)只需一個(gè)傳感器。對(duì)于不規(guī)則冠層或混合樹(shù)種，大樹(shù)的莖流速率在樹(shù)周不同方向上存在差異，一棵樹(shù)需要使用多個(gè)傳感器才能準(zhǔn)確測(cè)量莖流。直徑在75~150 mm的樹(shù)木，每棵樹(shù)通常需安裝2套傳感器；直徑在150~440 mm的樹(shù)木，每棵樹(shù)安裝4套傳感器。

系統(tǒng)特點(diǎn)

雙探針，Granier磚利設(shè)計(jì)

探針易插拔，可重復(fù)使用

恒溫加熱，采用熱擴(kuò)散方法，而不是準(zhǔn)確度較差的熱脈沖方法

可以連續(xù)測(cè)量（熱脈沖方法不可以，有等待周期）

應(yīng)用案例

（1）西北農(nóng)林科技大學(xué) 秦嶺

參考文獻(xiàn)

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