EGU22-12203
https://doi.org/10.5194/egusphere-egu22-12203
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Atmospheric blocking and the contribution of transient waves to its onset, decay and maintenance 

Charlie Suitters1, Oscar Martinez-Alvarado2, Kevin Hodges2, Reinhard Schiemann2, and Duncan Ackerley3
Charlie Suitters et al.
  • 1Department of Meteorology, University of Reading, Reading, United Kingdom (c.c.suitters@pgr.reading.ac.uk)
  • 2National Centre for Atmospheric Science, University of Reading, Reading, United Kingdom
  • 3Met Office, Exeter, United Kingdom

A full understanding of the dynamical behaviour of atmospheric blocking is still lacking, despite the influence of blocking towards hazardous mid-latitude weather extremes. Using geopotential height anomalies, relative to the zonal mean flow and persistent longitude-dependent eddies, and an objective feature tracking algorithm, the climatologies and lifecycles of anticyclones that contribute to blocking events are explored. Case studies and a climatology for blocking are presented using this process, and results show that this method performs favourably in relation to existing block detection methods since most blocking configurations are successfully detected. Then, blocking events are classified according to location of occurrence and persistence, and characteristics including intensity and areal extent are examined. The anticyclonic features contributing to blocks are also studied in terms of their genesis and lysis regions, along with anomaly strength and speed. It is found that many of the anticyclonic features that enter a block form a long way upstream, before travelling along the Rossby wave guide and intensify in the block. Furthermore, anticyclonic features that leave a block can then proceed to re-intensify further downstream and be part of a further blocking episode in a new location. This shows that there is an inherent interaction between transient waves and stationary blocks, and these results provide evidence for the previously-proposed selective absorption mechanism (SAM) for block maintenance.

How to cite: Suitters, C., Martinez-Alvarado, O., Hodges, K., Schiemann, R., and Ackerley, D.: Atmospheric blocking and the contribution of transient waves to its onset, decay and maintenance , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12203, https://doi.org/10.5194/egusphere-egu22-12203, 2022.

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