资源环境科技发展态势分析平台

Methane (CH4) emissions from thawing permafrost amplify a climate warming feedback. However, upscaling of site-level CH4 observations across diverse Arctic landscapes remains highly uncertain, compromising accuracy of current pan-Arctic CH4 budgets and confidence in model forecasts. We report a 30,000-km(2) survey at 25-m(2) resolution (similar to 1 billion observations) of CH4 hotspot patterns across Alaska and northwestern Canada using airborne imaging spectroscopy. Hotspots covered 0.2% of the surveyed area, concentrated in the wetland-upland ecotone, and followed a two-component power law as a function of distance from standing water. Hotspots decreased sharply over the first 40 m from standing water (y = 0.21 x(-0.649), R-2 = 0.97), mirroring in situ flux observations. Beyond 40 m, CH4 hotspots diminished gradually over hundreds of meters (y = 0.004 x(-0.164), R-2 = 0.99). This emergent property quantifies the distribution of strong methanogenic zones from site to regional scales, vastly improving metrics for scaling ground-based CH4 inventories and validation of land models.