Increasing trend of vertical wind shear revealed by high-resolution radiosonde data over the United States

Vertical wind shear (VWS) in the upper troposphere and lower stratosphere (UTLS) affects jet stream, gravity-wave propagation, and turbulence. Although reanalyses have suggested increasing UTLS VWS under climate change, observational evidence remains limited by coarse vertical resolution and the scarcity of long-term datasets. Here we analyze 20 years (2005–2024) of high vertical-resolution radiosonde data from 68 stations across the contiguous United States to quantify VWS between 300 and 200 hPa and compare it with ERA5. Bulk-layer outer-VWS shows spatial patterns similar to ERA5 but with larger magnitudes. In contrast, fine-scale mean and maximum VWS are stronger at higher latitudes, opposite to the meridional structure of large-scale VWS. Fine-scale VWS also exhibits substantially stronger positive trends, with maximum VWS increasing at 7.4% per decade. These increases indicate intensifying fine-scale VWS across the United States and suggest a growing risk of aviation turbulence beyond that inferred from coarse-resolution reanalyses.