Future Changes in the Winter Beaufort High Under Warming Climate Scenarios

We show that the winter Beaufort High (BH) index defined by sea level pressure (SLP) has a robust negative trend under the scenarios SSP5-8.5 and SSP2-4.5, with a reduction by about 5 hPa and 2 hPa, respectively, by the end of the 21st century. The negative trends in the BH SLP are associated with the changes in the background SLP over the Arctic basin. However, the vorticity of the winter BH tends to intensify under SSP5-8.5, but shows no robust increase under SSP2-4.5. The intensification is associated with the enhanced ridge over the Western Arctic. Therefore, it is necessary to take into account the dynamic aspects of the BH, such as vorticity. Based on this assessment, under the most likely emissions scenario, the winter BH is likely to weaken through the 21st century, in terms of SLP, but shows no robust changes in term of vorticity. We used the latest IPCC global climate model outputs to investigate the wintertime changes in the Beaufort High (BH). Under the climate change scenarios, during winter, the sea level pressure (SLP) over the BH region is expected to decrease. The SLP reduction is up to 5 hPa by the end-of-the-century. Thus, the BH seems to become weaker. However, its vorticity tends to increase under SSP5-8.5, mostly due to the intensification of the ridge over the western North America. The Beaufort High (BH) index defined by sea level pressure (SLP) decreases under warming climate scenarios Meanwhile, the BH vorticity tends to intensify due to the change in the ridge over the Western Arctic Besides the SLP, impact studies of the BH on the Arctic Ocean need to consider its dynamics such as vorticity