The interannual variability of compound hot–dry events over the Tibetan Plateau is modulated by ENSO and the SNAO. Credit: Rongyun Pan
Since the 1950s, the Tibetan Plateau has experienced pronounced warming and wetting. However, an overall shift toward wetter conditions does not necessarily mean that drought risk has diminished. On the contrary, against the backdrop of continued warming, compound hot-dry events—characterized by the simultaneous occurrence of high temperatures and drought—have become an increasingly important climate risk across the plateau.
Such extremes can directly affect ecosystems and water resources, accelerate glacier retreat and permafrost degradation, destabilize glaciers and high-mountain geomorphic systems, and potentially increase the risk of secondary hazards such as ice avalanches and landslides. Yet the processes governing the year-to-year variability of these compound hot-dry events remain poorly understood.
A recent study, published in Journal of Geophysical Research: Atmospheres and led by Professor Tianjun Zhou's research team at the Institute of Atmospheric Physics, Chinese Academy of Sciences, has helped fill this knowledge gap.
"We found that the year-to-year swings in these compound hot-dry events are not random—they are largely steered by two major climate modes: ENSO and the Summer North Atlantic Oscillation," says lead author Rongyun Pan, a doctoral candidate at the institute. The study shows that these large-scale patterns modulate atmospheric circulation and surface energy balance across the plateau, driving alternating hot-dry and cool-wet summers.
