Retrieval of Grassland Live Fuel Moisture Content by Parameterizing Radiative Transfer Model With Interval Estimated LAI
Retrieval of Grassland Live Fuel Moisture Content by Parameterizing Radiative Transfer Model With Interval Estimated LAI
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区间估计LAI参数化辐射传输模型反演草地活燃料含水量
DOI：
10.1109/jstars.2015.2472415
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发表时间：
2016-02
影响因子：
5.5
通讯作者：
Liao Zhanmang
中科院分区：
文献类型：
--
作者：
Quan Xingwen;He Binbin;Li Xing;Liao Zhanmang
可燃物含水量是森林火灾风险评估中的重要因子，但在利用辐射传输模型反演时，叶面积指数会影响可燃物含水量的估算。为了减少LAI在LFMC反演过程中的影响，我们使用区间估计的LAI来参数化PROSAIL（前景+ SAIL）辐射传输模型。首先使用简单的降尺度技术基于MODIS LAI产品（MOD 15 A2）估计LAI值，然后使用区间估计方法在80%、90%和95%的置信水平下进行约束。为了评估这种方法的可靠性，另外两个LAI约束策略，弱约束LAI在很宽的范围内和强约束LAI固定值。建立了参数化PROSAIL模型的查找表。此外，还可以利用Landsat TM和8种产品反演出低层大气环流。结果表明，在95%置信水平下，用区间估算的叶面积指数反演的LFMC精度最高（R2 = 0.78，RMSE = 35.80%），略优于在90%置信水平下使用区间估计LAI时获得的LFMC（R2 = 0.75，RMSE = 39.38%）和80%（R2 = 0.70，RMSE = 41.21%）。使用弱约束LAI（R2 = 0.64，RMSE = 41.68%）和强约束LAI（R2 = 0.68，RMSE = 45.53%）检索的LFMC的准确性水平较差。因此，本研究表明，LFMC反演可以通过使用区间估计的叶面积指数。
Live fuel moisture content (LFMC) is an important factor in wildfire risk assessment, but the estimation of LFMC is affected by the leaf area index (LAI) if it is retrieved using a radiative transfer model. To reduce the influence of LAI in the LFMC retrieval process, we used the interval estimated LAI to parameterize the PROSAIL (PROSPECT + SAIL) radiative transfer model. The LAI values were first estimated based on the MODIS LAI product (MOD15A2) using a simple downscaling technique, and then were constrained using an interval estimation method at the confidence levels of 80%, 90%, and 95%. To evaluate the reliability of this approach, another two LAI constraint strategies were applied, weakly constrained LAI over a wide range and strongly constrained LAI with fixed values. A look up table (LUT) was set up for the parameterized PROSAIL model. Furthermore, the LFMC can be retrieved based on the Landsat TM and 8 products. The results showed that the retrieved LFMC using the interval estimated LAI at the 95% confidence level resulted in the best accuracy level (R2 = 0.78, RMSE = 35.80%), which was slightly better than the LFMC obtained when using the interval estimated LAI at confidence levels of 90% (R2 = 0.75, RMSE = 39.38%) and 80% (R2 = 0.70, RMSE = 41.21%). The accuracy levels of the retrieved LFMC using weakly constrained LAI (R2 = 0.64, RMSE = 41.68%) and strongly constrained LAI (R2 = 0.68, RMSE = 45.53%) were poor. Thus, this study demonstrated that LFMC retrieval could be improved by using the interval estimated LAI.
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影响因子：
3.1
作者：
M. Plucinski;W. Anderson;R. Bradstock;A. Gill
通讯作者：
M. Plucinski;W. Anderson;R. Bradstock;A. Gill
DOI：
10.1016/0034-4257(85)90072-0
发表时间：
1984-02
期刊：
--
影响因子：
--
作者：
W. Verhoef
通讯作者：
W. Verhoef
DOI：
10.1109/jstars.2009.2014008
发表时间：
2009-02
影响因子：
5.5
作者：
M. Yebra;E. Chuvieco
通讯作者：
M. Yebra;E. Chuvieco
根据冠层含水量与树叶干生物量之比估算草地活燃料含水量
影响因子：
4.8
作者：
Quan Xingwen;He Binbin;Li Xing;Tang Zhi
通讯作者：
Tang Zhi
影响因子：
8.2
作者：
Pingheng Li;Quan Wang
通讯作者：
Pingheng Li;Quan Wang