Decadal changes in atmospheric circulation detected in cloud motion vectors

Changing atmospheric circulations shift global weather patterns and their extremes, with profound effects on human societies and ecosystems. Studies using atmospheric reanalysis and climate model data ^1-9 indicate a variety of circulation changes in recent decades but show discrepancies in magnitude and even direction. Therefore, validation with independent, climate-quality measurements is urgently needed ³ . Here we use the satellite-observed, height-resolved cloud motion vectors from the Multi-angle Imaging SpectroRadiometer (MISR) ^10,11 to analyze tropospheric circulation changes during 2000–2020. We find significant changes in tropospheric circulations, with upper tropospheric cloud motion speeds in midlatitudes increasing by up to ~4 m s⁻¹ decade⁻¹, primarily due to the strengthening of meridional flow that could indicate increased poleward trajectories or intensification of extratropical cyclones. Furthermore, the northern and southern hemisphere tropics shifted poleward at a rate of 0.42±0.22 and 0.02±0.14 °latitude decade⁻¹ (95% CI), respectively, while the corresponding polar front shifted at 0.37±0.31 and 0.31±0.21 °latitude decade⁻¹. Comparison with the widely used ERA5 ¹² reanalysis winds subsampled to MISR show good agreement with MISR’s climatological values and trends but indicate likely ERA5 biases in the upper troposphere. These MISR-based observations provide critical benchmarks for refining reanalysis and climate models to advance our understanding of climate change impacts on cloud and atmospheric circulations.