Arctic Tropospheric Warming Events are Increasing, With Impacts to Extreme Weather Events
Observational evidence for the tropical energy transports that fuel Arctic atmospheric warming events suggests that future mid-latitude weather may change and produce an increase in extreme, unseasonal weather patterns. These weather patterns are difficult to predict far ahead.
These warming events are connected to the loss of Arctic Sea ice, and together they can influence weather patterns that may change the frequency of extreme events in the mid-latitude region (severe flooding, winter storms and record cold spells). We point out the connections between these features and highlight the need to better understand and predict them.
Changes in atmospheric flows between December and January are often closely connected to extreme weather events worldwide (the New Year Winter Storms in the Eastern US and record cold spells). Operational forecast models have difficulty in predicting this kind of events beyond a week. We use analysis products from a weather center, and climate model simulations to better understand these features, and their connection to decreasing Arctic sea ice concentrations. We focus on two types of atmospheric features, Sudden Stratospheric Warmings (SSW) that warm at high altitudes (15km and above) and Rapid Tropospheric Warmings (RTW) that warm faster and nearer the surface. We find that RTW episodes have been increasing since the 1990s, and they are more strongly correlated with sea ice loss, highlighting the importance of better understanding of these features, and the need to predict them at longer (monthly to seasonal) timescales.