Estimating emissions from agricultural fires in the North China Plain based on MODIS fire radiative power

Crop-residue burning plays an important role in regional air quality and global climate change. The North China Plain, the largest winter wheat production district in China, experiences extensive crop fires during harvest seasons. Traditional methods to estimate emissions from crop fires depend strongly on burned area, biomass density, combustion efficiency, and emission factor. However, the uncertainty of burned area derived from satellites can be very large because the agricultural fires in China have small sizes and short duration. Using fire radiative power (FRP) to estimate emissions depends on a few numbers of parameters and has been applied in recent researches. In our study, emissions from crop burning in fields in the North China Plain were estimated using MODIS FRP derived from the Terra and Aqua satellites. The time-integrated FRP (i.e., fire radiative energy, FRE) in per fire pixel and fire counts are important factors in the estimation. The estimated results showed that high fire emissions were in 2005-2007 and 2012, while low emissions were in the fire years 2003 and 2004. Our estimated emissions were close to a previous study with an agricultural statistical approach, but significantly higher than emissions derived from the MODIS burned area product and Global Fire Emissions Database, respectively. The emission uncertainties in our study mainly originated from MODIS pixel resolution, emission factors, FRP measurements, and FRP parameterization. (C) 2015 Elsevier Ltd. All rights reserved.

作物秸秆焚烧在区域空气质量和全球气候变化中起着重要作用。华北平原是中国最大的冬小麦产区，在收获季节会发生大量的作物火灾。估算作物火灾排放的传统方法在很大程度上取决于燃烧面积、生物量密度、燃烧效率和排放因子。然而，由于中国的农业火灾规模小且持续时间短，从卫星获取的燃烧面积的不确定性可能非常大。利用火灾辐射功率（FRP）来估算排放取决于少数几个参数，并且已在近期的研究中得到应用。在我们的研究中，利用从泰拉（Terra）和阿卡（Aqua）卫星获取的中分辨率成像光谱仪（MODIS）火灾辐射功率估算了华北平原农田作物焚烧的排放。每个火灾像元的时间积分火灾辐射功率（即火灾辐射能量，FRE）以及火灾次数是估算中的重要因素。估算结果表明，2005 - 2007年和2012年火灾排放较高，而2003年和2004年火灾年份排放较低。我们估算的排放与先前采用农业统计方法的一项研究结果相近，但分别明显高于从MODIS燃烧面积产品和全球火灾排放数据库得出的排放。我们研究中的排放不确定性主要源于MODIS像元分辨率、排放因子、火灾辐射功率测量以及火灾辐射功率参数化。（C）2015爱思唯尔有限公司。保留所有权利。