| Comparison of three different satellite-based approaches for aboveground biomass estimation |
| Paper ID : 1021-SMPR |
| Authors: |
|
Ali Mokhtari *1, Hamideh Noory2, Abdullah Balkhi2 1Remote Sensing Department, Iranian Space Agency (ISA), Alborz, Iran. 2Department of Irrigation and Reclamation Engineering, University of Tehran, Alborz, Iran. |
| Abstract: |
| Estimating crop yield on regional scales in a short time with low cost would only be possible by the means of remote sensing. Several approaches have been proposed based on remotely sensed data for estimating aboveground biomass. In this study, three satellite-based approaches including Monteith, SWAP, and FAO33 were evaluated in Hezarjolfa, in the Qazvin irrigation network, Iran. First, the performance of MODIS and Landsat imagery in leaf area index (LAI) estimation were assessed against measured data. Then remotely sensed LAI along with relative evapotranspiration (ETrel) were assimilated into SWAP using a simple sequential updating algorithm. Meanwhile, the performance of four different spectral indices (SIs) such as normalized difference vegetation index (NDVI), simple ratio (SR), land surface water index (LSWI), and normalized difference water index (NDWI) were discussed in the Monteith model for aboveground biomass estimation. At the end, a comparative analysis was executed in order to determine the best satellite-based approach using percent absolute error (PAE). Results showed that Landsat imagery with coefficient of determination (R2) of 0.785 and root mean square error (RMSE) of 0.81 m2.m-2 in LAI estimation had higher accuracy compared with MODIS imagery. Due to mixed pixels in MODIS, the spatial variations of LAI and subsequently forced errors upon SWAP simulations were not properly observed. Evaluation results of different SIs in the Monteith model showed that NDVI performed best with PAE of 1.54 percent. Also the Monteith model had 4.28 and 32.41 percent lower PAE compared to the SWAP and FAO33 methods, respectively. |
| Keywords: |
| Aboveground biomass, FAO33, Monteith, Spectral indices, SWAP |
| Status : Paper Accepted (Poster Presentation) |
