Exploring possible climate change amplification of warm-season precipitation extremes in the southeastern Alpine forelands at regional to local scales

Study Region:

Southeastern Alpine forelands, with the representative regions explored mainly located in Southeast Austria.

Study Focus:

Short duration extreme convective precipitation events (SDECPEs) are increasingly altered by climate change but such events are not properly detectable in reanalysis datasets like ERA5-Land. Data from the WegenerNet (WEGN) high-density station network and GeoSphere Austria’s INCA dataset provide higher resolution, making them more suitable for the investigation, but are available only for the most recent two decades. In this study we hence leverage the WegenerNet and INCA data for the high-resolution exploration of warm-season (Apr–Oct) SDECPEs and assess, through combination with (re)analysis data over 1961–2022, a potential climate-change-induced amplification of such sub-daily precipitation extremes. We prepared a SDECPE classification to this end and employ a new class of threshold-exceedance-amount (TEA) metrics for the long-term analysis.

New hydrological insights for the region:

Even though extreme hourly-scale precipitation is expected to increase with rising temperatures, we find that this strongly varies at local scales within the region. While some subregions show an amplification higher than the Clausius–Clapeyron relation would suggest, and beyond estimated natural variability, others exhibit a decrease in extreme precipitation. The inspected ratios between maximum and average hourly precipitation and the TEA metrics enabled deeper insights into the changes of these extremes. Also the vital need for long-term high-resolution precipitation observations was strongly evidenced.