Since the Green Revolution in the mid-1960s, a widespread transition to a rice-wheat rotation in the Indian state of Punjab has led to steady increases in crop yield and production. After harvest of the summer monsoon rice crop, the burning of excess crop residue in Punjab from October to November allows for rapid preparation of fields for sowing of the winter wheat crop. Here we use daily satellite remote sensing data to show that the timing of peak post-monsoon fire activity in Punjab and regional aerosol optical depth (AOD) has shifted later by approximately two weeks in Punjab from 2003-2016. This shift is consistent with delays of 11-15 days in the timing of maximum greenness of the monsoon crop and smaller delays of 4-6 days in the timing of minimum greenness during the monsoon-to-winter crop transition period. The resulting compression of the harvest-to-sowing period coincides with a 40% increase in total burning and ~50% increase in regional AOD. Potential drivers of these trends include agricultural intensification and a recent groundwater policy that delays sowing of the monsoon crop. The delay and amplification of burning into the late post-monsoon season suggest greater air quality degradation and public health consequences across the densely-populated Indo-Gangetic Plain.

中文翻译：

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检测印度旁遮普省季风后农业燃烧的延迟：空气质量的潜在驱动因素和后果

自 1960 年代中期的绿色革命以来，印度旁遮普邦向稻麦轮作的广泛过渡导致作物产量和产量稳步增长。夏季季风水稻收割后，旁遮普省 10 月至 11 月期间多余的作物残留物被燃烧，从而可以快速准备播种冬小麦作物的田地。在这里，我们使用每日卫星遥感数据显示旁遮普省季风后火灾活动高峰时间和区域气溶胶光学深度 (AOD) 从 2003 年到 2016 年在旁遮普省推迟了大约两周。这种转变与季风作物最大绿化时间延迟 11-15 天以及季风到冬季作物过渡期间最小绿化时间延迟 4-6 天的情况相一致。由此产生的收获到播种期的压缩与总燃烧量增加 40% 和区域 AOD 增加约 50% 相吻合。这些趋势的潜在驱动因素包括农业集约化和最近推迟季风作物播种的地下水政策。季风后期后期燃烧的延迟和扩大表明，人口稠密的印度恒河平原的空气质量恶化和公共卫生后果更加严重。