A hybrid remote sensing approach to quantifying crop residue burning in the United States

Crop residue burning is an important land use activity in the United States. Currently, satellite-based burned area methodologies specifically calibrated for crop residue burning are limited. This article describes a satellite observations- based hybrid approach to estimate the amount of burned crop residues that combines Moderate Resolution Imaging Spectroradiometer (MODIS) 8-day differencing of Normalized Burn Ratio (dNBR) burned area mapping with MODIS active fire counts calibrated into area. The dNBR approach utilizes the spectral response of the 2.1-gum shortwave infrared MODIS band to detect burned pixels. A time series of 8-day MODIS composites produces burned area estimates during harvest on a near-weekly scale. This approach was tested on the study area of MODIS tile h10v05, which encompasses much of the Mississippi River Delta and the southern Great Plains, for the years 2003 through 2006. Within this area, an average of 12,700 and 10,835 km2 burned in the spring and fall harvests, respectively. Results from the hybrid approach are validated through comparison with high-resolution Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and field data. Validation of the hybrid approach shows strong correspondence with both the ASTER (mean R2 = 0.92) and in-situ data (mean accuracy 85.5%). At the state level, the estimated burn rates from this analysis compare well with reported Arkansas burn rates. Results suggest potential for using the approach to monitor and quantify fire activity in cropland areas of the United States.