2003–2017年东北露天生物质燃烧时空变化特征

Spatial and temporal variability of open biomass burning in Northeast China from 2003 to 2017

近年来,露天生物质燃烧对我国东北重霾污染影响显著。本文综合利用MODIS C6火点产品以及下垫面类型产品,结合GFAS火点排放清单数据,定量研究了2003–2017年东北的火点演变特征。结果显示,东北区域近15年来火点震荡增加,并在2013–2017年达到峰值。火点季节变化明显,主要集中3–4月(占37%)和10–11月(占46%), 2013年之后春季火点突增,且在2016–2017年春季火点超过秋季。空间分布上,火点主要位于黑龙江(占71%),其次是吉林(16%)和辽宁(13%)。相比森林和草地下垫面类型,农田火点占比高达91%。本研究结果为东北区域露天生物质燃烧的重点监测时段和管控方案制订提供了参考依据。

Open biomass burning(OBB)has a significant impact on the heavy haze pollution in Northeast China(NEC)in recent years,which requires the investigation of the spatiotemporal variations of OBB with different vegetation types to better monitor and control OBB in NEC.The MODIS C6 fire and land cover products,together with the emissions inventory from the Global Fire Assimilation System,were used in this study.The changes in the total number of MODIS fire points in NEC from 2003 to 2017 demonstrated a fluctuating but generally rising trend,with a peak during 2013–2017.Most fire points concentrated in two key periods,i.e.March–April(37%)and October–November(46%).The total number of crop residue burnings in March–April was basically slightly fluctuating and increased sharply from 2013,whilst the number in October–November had a fluctuating and upward trend until 2015,when a decline appeared.The amount of OBB in March–April was higher than that in October–November during 2016–17.OBB in Heilongjiang Province comprised a major proportion of all fires,which accounted for 70.7%from 2003 to 2017;however,the proportion was only 66.2%during 2013–2017.The largest proportion of all fires was in cropland(90.8%),then forest(5.3%)and grassland(3.1%).The cumulative emissions of fine particulate matter,nitrogen oxides,and ammonia from agricultural open burning in NEC reached 78.43 Gg,24.9 Gg,and 13.7 Gg for March–April during 2013–17,respectively,which were close to those in October–November.