Open burning is illegal in Ukraine, yet Ukraine has, on average, 300 times more fire activity per year (2001–2019) than most European countries. In 2016 and 2017, 47% of Ukraine was identified as cultivated area, with a total of 70% of land area dedicated to agricultural use. Over 57% of all active fires in Ukraine detected using space-borne Visible Infrared Imaging Radiometer Suite (VIIRS) during 2016 and 2017 were associated with pre-planting field clearing and post-harvest crop residue removal, meaning that the majority of these fires are preventable. Due to the small size and transient nature of cropland burns, satellite-based burned area (BA) estimates are often underestimated. Moreover, traditional spectral-based BA algorithms are not suitable for distinguishing burned from plowed fields, especially in the black soil regions of Ukraine. Therefore, we developed a method to estimate agricultural BA by calibrating VIIRS active fire data with exhaustively mapped cropland reference areas (42 958 fields). Our study found that cropland BA was significantly underestimated (by 30%–63%) in the widely used Moderate Resolution Imaging Spectroradiometer-based MCD64A1 BA product, and by 95%–99.9% in Ukraine’s National Greenhouse Gas Inventory. Although crop residue burns are smaller and emit far less emissions than larger wildfires, reliable monitoring of crop residue burning has a number of important benefits, including (a) improving regional air quality models and the subsequent understanding of human health impacts due to the proximity of crop residue burns to urban locations, (b) ensuring an accurate representation of predominantly smaller fires in regional emission inventories, and (c) increasing awareness of often illegal managed open burning to provide improved decision-making support for policy and resource managers.

露天焚烧在乌克兰是非法的，但乌克兰平均每年（2001-2019 年）的火灾活动是大多数欧洲国家的 300 倍。2016 年和 2017 年，乌克兰 47% 的土地被确定为耕地，总共有 70% 的土地用于农业用途。在 2016 年和 2017 年期间，使用星载可见红外成像辐射计套件 (VIIRS) 检测到的乌克兰所有活跃火灾中，超过 57% 与种植前田间清理和收获后作物残留物清除有关，这意味着这些火灾中的大多数是可以预防的。由于农田烧毁的面积小且具有短暂性，基于卫星的烧毁面积 (BA) 估计值经常被低估。此外，传统的基于光谱的 BA 算法不适合区分烧地和耕地，尤其是在乌克兰的黑土地区。因此，我们开发了一种通过校准 VIIRS 活动火灾数据与详尽绘制的农田参考区域（42 958 块田）来估算农业 BA 的方法。我们的研究发现，在广泛使用的基于中分辨率成像光谱仪的 MCD64A1 BA 产品中，农田 BA 被显着低估（30%–63%），在乌克兰的国家温室气体清单中被低估了 95%–99.9%。尽管与较大的野火相比，作物残留物燃烧较小且排放量少得多，但对作物残留物燃烧的可靠监测具有许多重要好处，包括 (a) 改善区域空气质量模型以及随后对人类健康影响的了解作物残留物燃烧到城市地区，(b) 确保准确反映区域排放清单中主要较小的火灾，