Röthlisberger Matthias, Frossard Linda, Bosart Lance F., Keyser Daniel, Martius Olivia (2019), Recurrent Synoptic-Scale Rossby Wave Patterns and Their Effect on the Persistence of Cold and Hot Spells, in Journal of Climate
, 32(11), 3207-3226.
Pohorsky Roman, Roethlisberger Matthias, Grams Christian, Ripoldi Jacopo, Martius Olivia (2019), The climatological impact of recurving North Atlantic tropical cyclones on downstream extreme precipitation events, in Monthly Weather Review
Trefalt Simona, Martynov Andrey, Barras Hélène, Besic Nikola, Hering Alessandro M., Lenggenhager Sina, Noti Pascal, Röthlisberger Matthias, Schemm Sebastian, Germann Urs, Martius Olivia (2018), A severe hail storm in complex topography in Switzerland - Observations and processes, in Atmospheric Research
, 209, 76-94.
Riboldi Jacopo, Röthlisberger Matthias, Grams Christian M. (2018), Rossby Wave Initiation by Recurving Tropical Cyclones in the Western North Pacific, in Monthly Weather Review
, 146(5), 1283-1301.
RoethlisbergerMatthias (2018), Full Access Northern Hemisphere Rossby Wave Initiation Events on the Extratropical Jet—A Climatological Analysis, in Journal of Climate
Röthlisberger Matthias, Martius Olivia, Wernli Heini (2016), An algorithm for identifying the initiation of synoptic-scale Rossby waves on potential vorticity waveguides, in Quarterly Journal of the Royal Meteorological Society
, 142(695), 889-900.
Röthlisberger Matthias, Pfahl Stephan, Martius Olivia (2016), Regional-scale jet waviness modulates the occurrence of midlatitude weather extremes, in Geophysical Research Letters
, 43(20), 10,989-10,997.
Synoptic-scale Rossby waves (RW) together with jets and vortices form the building blocks of tropopause level dynamics. They play a key role for the daily surface weather evolution, including the formation of extreme weather events. Synoptic-scale RW are closely tied to the propagation of forecast errors in numerical weather prediction systems. More recently a vivid debate on the effects of global change on RW dynamics and the associated extreme weather has received a lot of attention. In this project the triggering phase of synoptic-scale RW will be investigated. We plan to study in detail the dynamical processes that are crucial in a very early stage of the life-cycle of a RW. To this end an algorithm is developed that objectively detects the formation phase of synoptic-scale RW in reanalysis data sets. The algorithm will use the “waviness” of the jet waveguides on the dynamical tropopause to search for time instances where locally a transition occurs from an undisturbed waveguide to a growing wave disturbance. The time, the longitudinal sector and the type of waveguide (extratropical, subtropical) will be extracted to compile a climatology of wave triggering events in all four seasons and for both the northern and the southern hemisphere.Based on this data set the role of different wave triggering mechanisms described will be investigated from a potential vorticity (PV) point of view for a large number of triggering events. Wave triggering mechanisms include: the recurvature of a tropical cyclone, outflow from meso-scale convective systems in the vicinity of the waveguide, and stratospheric high PV anomalies approaching the waveguide. The role of each of these processes for triggering RW in different seasons and different geographical areas will be quantified. In addition one process, the so-called PV couplet triggering process, i.e. the joint propagation of a stratospheric high- and low-PV anomaly toward the waveguide will be investigated in more detail.