Search Results

You are looking at 1 - 10 of 10 items for :

  • Predictability and Dynamics of Weather Systems in the Atlantic-European Sector (PANDOWAE) x
  • All content x
Clear All
Olivia Martius and Heini Wernli

form in an initially jet-free atmosphere through the stirring by baroclinic eddies only (e.g., Lee 1997 ). The eddy-driven jets are located in areas with strong surface baroclinicity in the extratropics. Subtropical (“shallow”) jets are located at the poleward edge of the Hadley cell and owe their existence in a first approximation to the transport of angular momentum from the tropics into the subtropics (e.g., Held and Hou 1980 ). It has been shown that subtropical eddies can significantly

Full access
Simon T. K. Lang, Sarah C. Jones, Martin Leutbecher, Melinda S. Peng, and Carolyn A. Reynolds

experiments with lower-resolution moist and dry SVs. The spread differences between TL255 and TL95 moist SVs are larger than the differences between TL255 moist and dry SVs. When Helene is located within the tropics the spread at upper levels for the TL255 moist SVs is considerably larger in comparison to the TL255 dry SVs (up to 130%), with smaller differences at lower levels. For the case initialized at 1200 UTC 17 September 2006 Helene is still located in the subtropics after 48-h forecast time. At 850

Full access
Martin Weissmann, Florian Harnisch, Chun-Chieh Wu, Po-Hsiung Lin, Yoichiro Ohta, Koji Yamashita, Yeon-Hee Kim, Eun-Hee Jeon, Tetsuo Nakazawa, and Sim Aberson

to a single aircraft deployed through the Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region (DOTSTAR) program ( Wu et al. 2005 ). In autumn 2008, an international effort by several countries in North America, East Asia, and Europe was made to observe TCs in the western Pacific throughout their full life cycle from the genesis in the tropics until extratropical transition and the interaction with the midlatitude flow for the first time. These observations were conducted

Full access
Yannick Barton, Paraskevi Giannakaki, Harald von Waldow, Clément Chevalier, Stephan Pfahl, and Olivia Martius

. Precipitable water anomalies show no systematic patterns over Europe; they are positive in 2002 (>2 STD) and 2000 (>1 STD) but extremely weak in 1965 and 1993 ( Fig. 11 ). The extreme moisture fluxes on the Alpine south side are hence determined not only by the amount of precipitable water in the area but also by the magnitude of the wind responsible for the moisture advection. 2) Role of the tropics We will next discuss the role of tropical forcing. The clustering periods of 1993 and 2002 were both

Full access
Andreas Schäfler, Andreas Dörnbrack, Christoph Kiemle, Stephan Rahm, and Martin Wirth

) water vapor measurements in the tropics and subtropics over the Atlantic Ocean between Europe and Brazil. A mass flux (kg s −1 ) was calculated by Weissmann et al. (2005a) in a shallow stream toward the Alps using Doppler wind lidar (DWL) measurements. The first collocated lidar measurements of wind and water vapor were carried out during the International H 2 O Project (IHOP_2002) with a two-wavelength DIAL and a nonscanning DWL. Kiemle et al. (2007) used these observations to calculate

Full access
Christian M. Grams and Heather M. Archambault

diabatically enhanced outflow of the PRE is aligned along the midlatitude waveguide and initial ridge building occurs. Later during ET, the diabatic outflow of the transitioning TC turns from being directed into the tropics ( Fig. 10a ) to being directed directly into the initial downstream ridge R1 ( Fig. 10b ), which was strongly amplified. The ascent in the transitioning TC becomes more tilted [transition from air parcels located at >900 hPa (dark blue) close to the TC center to <200 hPa (red) to the

Full access
Lars Wiegand, Arwen Twitchett, Cornelia Schwierz, and Peter Knippertz

stratospheric intrusions over western Europe, although not all PV streamers produce such events. Martius et al. (2006) found a link between longer-lived PV streamers and greater amounts of accumulated precipitation as well as a higher probability of intense precipitation events. At low latitudes, PV streamers can trigger tropical convection ( Kiladis and Weickmann 1992 ; Slingo 1998 ), as well as mid- and high-level poleward- and eastward-extending cloud bands from the tropics into the subtropics denoted

Full access
Andrea Schneidereit, Dieter H. W. Peters, Christian M. Grams, Julian F. Quinting, Julia H. Keller, Gabriel Wolf, Franziska Teubler, Michael Riemer, and Olivia Martius

studies show that tropospheric processes like blocking anticyclones in the extratropics and like ENSO and MJO in the tropics influence the preconditioning of the polar vortex in advance of an MSSW event. Barriopedro and Calvo (2014) studied the relationship between ENSO, MSSWs, and blocking. They show that during the cold phase of ENSO (La Niña), blocking anticyclones frequently occur over the eastern Pacific and over the Scandinavian–Kara Sea region before MSSW events. Under mean La Niña conditions

Full access
Julian F. Quinting and Sarah C. Jones

wind. In this study, we apply , which is in the range of that was suggested by Glatt and Wirth (2014) . Finally, a meridional average between 20° and 80°N/S yields for each time a one-dimensional field varying in longitude only. This meridional average excludes the tropics and the poles from further consideration, but ensures that the entire extratropics are included. c. Compositing technique and statistical evaluation To investigate the modifications of RWP amplitude and frequency downstream

Full access
Julia H. Keller, Christian M. Grams, Michael Riemer, Heather M. Archambault, Lance Bosart, James D. Doyle, Jenni L. Evans, Thomas J. Galarneau Jr., Kyle Griffin, Patrick A. Harr, Naoko Kitabatake, Ron McTaggart-Cowan, Florian Pantillon, Julian F. Quinting, Carolyn A. Reynolds, Elizabeth A. Ritchie, Ryan D. Torn, and Fuqing Zhang

. Early during ET, ascent and associated latent heat release occurs mainly in the convection near the cyclone center (exemplified by trajectories depicted in Fig. 5a ). At the same time, the cyclonic circulation of the transitioning cyclone advects warm and moist air masses out of the tropics toward the midlatitudes. When impinging on the baroclinic zone ( Figs. 5a,b ), these air masses begin to ascend slantwise along the sloping moist isentropes and convective bursts with associated latent heat

Open access