The role of latent heating in atmospheric blocking

by Daniel Steinfeld (ETH-Zurich)


Recent studies have pointed to an important role of latent heating for the formation and maintenance of prolonged anticyclonic circulation anomalies, denoted as atmospheric blocking. However, the effect of latent heating on blocking is not yet well understood.

This presentation will provide an overview of the role of latent heating in atmospheric blocking dynamics with two different approaches: (i) a global climatological analysis based on air parcel trajectory calculation with ERA-Interim reanalysis and (ii) numerical sensitivity experiments with modified upstream latent heating for five selected blocking events with the global weather prediction model IFS.

The results show a strong influence of latent heating on blocking and the midlatitude flow due to the injection of air masses with low potential vorticity (PV) into the upper troposphere in strongly ascending “warm conveyor belt” airstreams and the interaction of the associated divergent outflow with the upper-level PV structure.