第二届未来大气科学论坛

        Global warming has driven significant increases in extreme hydrological events, exhibiting pronounced spatial inhomogeneity. Recent studies have shown that the spatial inhomogeneity of global precipitation is intensifying, characterized by large-scale concurrent extreme rainfall or drought. Although studies have analyzed the effects of extreme wet/dry conditions on vegetation growth, the ecological response of vegetation to hydrological spatial inhomogeneity as an independent stress factor remains unclear. Here, we first defined weather-scale inhomogeneous hydrological extremes (IHEs) and analyzed their spatiotemporal changes in China. Then we investigated the physical mechanism of IHE evolution by diagnosing spatial changes of vertical motion and atmospheric moisture. Finally, by applying solar-induced chlorophyll fluorescence (SIF) anomalies, we assess the ecological stress effects of IHEs on vegetation growth.
        Results show that: (1) Since the beginning of the 21st century, the annual frequency, annual cumulative duration, and annual cumulative affected area of IHEs in China have increased significantly by 2.1 events, 14.5 days, and 4.5×10⁶km² per decade, respectively, with the affected area rapidly expanding from regional to the national scale. (2) The increased inhomogeneity of weather-scale thermodynamic condition is the primary driver of the rise of IHEs, and, overlapped with a climatological northward intensification of mean precipitation, it shapes the current “Wet-North and Dry-South” pattern of IHEs. (3) The increasing occurrence and expansion of IHEs pose a severe threat to vegetation growth in China, with extensive hydrological extremes across multiple regions amplifying ecological stress and causing national-scale impacts. By quantifying the extremes of hydrological spatial patterns, we provide a new perspective for assessing ecological vulnerability under climate change. The sharp rises of IHEs may threaten national food security and reduce the effectiveness of previous ecological restoration projects, highlighting the need for stronger hydrological management to reduce future risks.

极端降水,空间不均匀性,极端干旱,植被胁迫,气候变化