基于遥感的千烟洲人工林蒸散及其组分模拟研究

论文通过改进遥感蒸散模型的关键参数,结合遥感数据和气象观测数据,对2003—2008年江西千烟洲人工林生态系统蒸散及其组分进行模拟,并利用涡度相关技术获取的蒸散实测数据对模型模拟结果进行验证和评价。结果表明:①年均蒸散总量模拟值比实测值偏低2.4%,决定系数与均方根误差分别为0.83和0.61 mm·d^-1。②土壤蒸发、林冠截留蒸发和植被蒸腾分别占总蒸散量的12%、23%和65%。其中,土壤蒸发季节及年际变化相对稳定;林冠截留蒸发季节变化明显且在不同年份差异较大;植被蒸腾季节变化明显,但年际变异较小。③1—3月植被光合作用较弱,植被蒸腾与蒸散比小于30%。随着植被蒸腾的增强,从4月开始植被蒸腾与蒸散比迅速增加,在生长旺季(7月底)可达到约90%。由于该模型所需数据在区域尺度较易获取,从而为开展区域尺度中亚热带人工林生态系统蒸散及其组分模拟提供方法支撑。

Modeling Evapotranspiration and Its Components in Qianyanzhou Plantation Based on Remote Sensing Data

In this study,with the verification and improvement to the evapotranspiration(ET)model(PT-Fi model),we simulate the ET and its components of the planted coniferous forest ecosystem at Qianyanzhou during 2003 and 2008 by using remote sensing data from MODIS and meteorological data.The estimated ET is compared with the observation from eddy flux tower sites.The results show that the simulated annual ET is about 2.4% lower than measurement,with a decision coefficient value(R2) of 0.83 and root mean square error of 0.61 mm·d-1.As to the ET components,soil evaporation is 12% of simulated ET with relative stability at seasonal and interannual scale.With obvious seasonal and interannaual variability,interception evaporation contribute 23% of the ET and with the same change tendency as precipitation.Canopy transpiration is about 65% of ET with obvious seasonal variation and interannual stability.During January to March,photosynthesis isn’t to be strong,canopy transpiration and evapotranspiration ration(T/ET) less than 30%,with the enhance of canopy transpiration,T/ET increases rapidly after April,in the end of July up to about 90%.Because of the data is easy to get at regional dimension in this model,which can lay a foundation for the further scaling up of evapotranspiration estimation in subtropical coniferous forest.