.png){kind=icon}
.png){kind=icon}
Return
A climatological perspective on cyclones and surface impacts in the Eastern Mediterranean using potential vorticity-based classification
.png){kind=icon}
OA
AI
T
L
S
DOI：10.5194/wcd-7-959-2026.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Abstract. The Eastern Mediterranean is a water-scarce; climate-sensitive region. Eastern-Mediterranean cyclones (EMCs) are a major contributor to precipitation totals and weather extremes; including heavy precipitation; strong winds; temperature extremes and dust storms; substantially impacting the population and natural environment. Understanding EMCs' variability and their associated impacts is essential for improving their predictability and forecasts. The large case-to-case variability of cyclone development and associated impacts calls for EMC classification that incorporates dynamical insight into EMC large-scale setting; their track characteristics and associated surface weather. Here we classify EMCs based on their associated upper-tropospheric potential vorticity (PV) structures; providing a novel process-based framework for quantifying cyclone-associated surface weather and extremes. Using the self-organising map (SOM) algorithm to categorise ERA5-based PV distributions during EMCs from 1979–2020; six distinct PV patterns highlight different governing large-scale and synoptic settings. Each EMC type involves distinct mean and extreme surface weather signatures. Two clusters with high PV anomalies over the eastern Mediterranean dominate the regional annual precipitation. A strong ridge upstream of the PV trough during Rossby wave breaking leads to enhanced precipitation; compared to a similar PV configuration with a weak ridge upstream. Temperature anomalies during the cyclone passage are strongly linked to upper-level PV patterns; with certain EMC types causing notable near-surface warm and cold temperature extremes. In transition and warm seasons; occasional extreme localised precipitation is found despite the prevalence of shallow thermal lows with weak upper-tropospheric PV anomalies and generally no/low precipitation amounts. While the annual frequency of EMCs exhibits no significant trend; some clusters show contrasting trends. A notable increase in the frequency of non-precipitating EMCs; indicates a potential shift toward drier; but occasionally more extreme conditions in the region. Through this classification approach the link between EMCs large-scale setting and their surface impacts is systematically mapped. These findings provide a framework for the evaluation of cyclones and their prediction; and may improve strategies for managing the societal and environmental impacts of EMCs at weather and climate timescales.
Journal
W
IF:
5.3
Papers:
442
Citations:
1.2K