What Are The Potential Implications Of A 5-10 HPa Increase In Winter-time 500-hPa Geopotential Height Anomalies Over The Greenland Ice Sheet On The Blocking Frequency And Persistence Of European Rossby Waves, And How Might This Affect The Simulation Of Heavy Precipitation Events In Western Europe Using The ERA-Interim Reanalysis Dataset Versus The Newer ERA5 Reanalysis?

The increase in 500-hPa geopotential height anomalies over Greenland during winter suggests a stronger high-pressure system, which can enhance blocking frequency and persistence. This, in turn, disrupts the normal progression of European Rossby waves, potentially leading to more persistent weather patterns. Such persistence can increase the likelihood of heavy precipitation events in western Europe by altering the trajectory and intensity of weather systems, possibly through more frequent or intense atmospheric rivers.

Comparing ERA-Interim and ERA5 reanalysis datasets, ERA5's higher spatial and temporal resolution, along with improved model physics, allows for a more accurate simulation of blocking events and associated precipitation dynamics. ERA5 better captures the nuances of Rossby wave behavior and the influence of Greenland's high-pressure system, leading to more reliable simulations of heavy precipitation events. In contrast, ERA-Interim's coarser resolution may result in less accurate depictions of these phenomena. Thus, ERA5 is expected to provide a more precise representation of the impacts of blocking on European weather patterns.