针对SCOPE(soil canopy observation of photosynthesis and energy fluxes)模型模拟冠层净辐射(0.4~2.5μm短波净辐射+2.5~50μm长波净辐射)时假设叶片空间随机分布的问题,开发考虑叶片空间聚集的冠层净辐射模拟新模型。将SCOPE模型的...针对SCOPE(soil canopy observation of photosynthesis and energy fluxes)模型模拟冠层净辐射(0.4~2.5μm短波净辐射+2.5~50μm长波净辐射)时假设叶片空间随机分布的问题,开发考虑叶片空间聚集的冠层净辐射模拟新模型。将SCOPE模型的短波净辐射模块和长波净辐射模块分别用考虑叶片空间聚集的GOST2模型和UFR97模型替换,形成新的冠层净辐射模拟模型NRC(modeling canopy net radiation considering spatial clumping index of leaves);通过浙江省安吉县1个毛竹(Phyllostachys edulis)林样地(1~4年生异龄林,4500株/hm^(2))2023年整年的观测数据验证,对比SCOPE模型和NRC模型对冠层净辐射的模拟结果。SCOPE模型和NRC模型对冠层净辐射的模拟结果都与观测值有强相关性,决定系数(R^(2))分别为0.97和0.99,均方根误差(RMSE)分别为47.24和13.31 W/m^(2)。SCOPE模型模拟得到的短波净辐射(R_(notot))存在低估(R^(2)=0.96,平均偏差MBE=-14.17 W/m^(2)),长波净辐射(R nttot)存在高估(R^(2)=0.46;MBE=50.27 W/m^(2)),而NRC模型分别成功模拟了R_(notot)(R^(2)=0.99,MBE=1.44 W/m^(2))和R nttot(R^(2)=0.71;MBE=1.34 W/m^(2))。NRC模型具备模拟叶片空间聚集条件下冠层净辐射的潜力。展开更多
We investigated the impact of convexity and isoperimetric deficits on the accuracy of sectional area estimates of tree stems using traditional methods(caliper,tape,formulas based on stem diameter and circumference).In...We investigated the impact of convexity and isoperimetric deficits on the accuracy of sectional area estimates of tree stems using traditional methods(caliper,tape,formulas based on stem diameter and circumference).In two complementary experiments,the use of photographs to estimate cross-sectional areas was first validated,then the use of a caliper and diameter tape was computer-simulated.The results indicated that the photographic method offers high precision,with mean relative errors below 0.1%,minimal deviation,and no significant bias,and the traditional methods led to substantial and systematic errors,with deviations from circularity and convexity significantly increasing the errors in area estimation.展开更多
文摘针对SCOPE(soil canopy observation of photosynthesis and energy fluxes)模型模拟冠层净辐射(0.4~2.5μm短波净辐射+2.5~50μm长波净辐射)时假设叶片空间随机分布的问题,开发考虑叶片空间聚集的冠层净辐射模拟新模型。将SCOPE模型的短波净辐射模块和长波净辐射模块分别用考虑叶片空间聚集的GOST2模型和UFR97模型替换,形成新的冠层净辐射模拟模型NRC(modeling canopy net radiation considering spatial clumping index of leaves);通过浙江省安吉县1个毛竹(Phyllostachys edulis)林样地(1~4年生异龄林,4500株/hm^(2))2023年整年的观测数据验证,对比SCOPE模型和NRC模型对冠层净辐射的模拟结果。SCOPE模型和NRC模型对冠层净辐射的模拟结果都与观测值有强相关性,决定系数(R^(2))分别为0.97和0.99,均方根误差(RMSE)分别为47.24和13.31 W/m^(2)。SCOPE模型模拟得到的短波净辐射(R_(notot))存在低估(R^(2)=0.96,平均偏差MBE=-14.17 W/m^(2)),长波净辐射(R nttot)存在高估(R^(2)=0.46;MBE=50.27 W/m^(2)),而NRC模型分别成功模拟了R_(notot)(R^(2)=0.99,MBE=1.44 W/m^(2))和R nttot(R^(2)=0.71;MBE=1.34 W/m^(2))。NRC模型具备模拟叶片空间聚集条件下冠层净辐射的潜力。
文摘We investigated the impact of convexity and isoperimetric deficits on the accuracy of sectional area estimates of tree stems using traditional methods(caliper,tape,formulas based on stem diameter and circumference).In two complementary experiments,the use of photographs to estimate cross-sectional areas was first validated,then the use of a caliper and diameter tape was computer-simulated.The results indicated that the photographic method offers high precision,with mean relative errors below 0.1%,minimal deviation,and no significant bias,and the traditional methods led to substantial and systematic errors,with deviations from circularity and convexity significantly increasing the errors in area estimation.
