A new study published in Advances in Atmospheric Sciences reveals that extreme warm events in Greenland are not all the same—and understanding the difference is key to predicting their impact on ice melt and global sea level rise.
Led by Prof. Lianlian Xu from Sun Yat-sen University, the research team analyzed 44 years of atmospheric data and identified two distinct types of extreme warm events in Greenland during summer: warm-wet events (WWEs) and warm-dry events (WDEs). While both involve unusually high temperatures, their underlying weather patterns and physical mechanisms are fundamentally different.
The study found that warm-wet events occur nearly twice as often as warm-dry events. During a warm-wet event, a dipole pressure pattern forms—high pressure to the east of Greenland and low pressure to the west—which pulls warm, moist air from the North Atlantic onto the ice sheet. This increases cloud cover and traps heat through enhanced downward longwave radiation, leading to warming and precipitation.
In contrast, warm-dry events are dominated by a powerful “Ω-blocking” high-pressure system that sits directly over Greenland. This blocks moisture from arriving, reduces cloud cover, and allows more sunlight to reach the surface through increased shortwave radiation. The result is intense warming under clear skies.
“These two types of events may look similar in temperature, but they are driven by completely different atmospheric setups,” said Prof. Xu. “Recognizing this helps us better understand how Greenland responds to climate change and how its ice sheet might evolve in the future.”
The study also highlights the role of the jet stream and Rossby waves. During warm-wet events, the jet stream is pulled westward, promoting wave energy dispersion and preventing a strong ridge from forming. During warm-dry events, the jet extends eastward, creating a “waveguide” that funnels energy toward Greenland and sustains the blocking high.
These findings offer new insights into the complex behavior of Arctic weather extremes and provide a scientific basis for improving predictions of their occurrence and impacts—especially critical as Greenland's ice loss continues to accelerate.
Advances in Atmospheric Sciences
Contrasting Atmospheric Drivers of Greenland’s Warm-Wet and Warm-Dry Extreme Events
13-Mar-2026