1 / 24

A case study of an explosively deepening diabatic Rossby-wave induced cyclone: the influence of environmental conditio

A case study of an explosively deepening diabatic Rossby-wave induced cyclone: the influence of environmental conditions. Maxi Böttcher and Heini Wernli. Institute for Atmospheric Physics University of Mainz, Germany. intro. What‘s a diabatic Rossby-wave?. Diabatic Rossby wave (DRW)

nia
Download Presentation

A case study of an explosively deepening diabatic Rossby-wave induced cyclone: the influence of environmental conditio

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A case study of an explosively deepeningdiabatic Rossby-wave induced cyclone:the influence of environmental conditions Maxi Böttcher and Heini Wernli Institute for Atmospheric Physics University of Mainz, Germany Maxi Böttcher

  2. intro What‘s adiabaticRossby-wave? Diabatic Rossby wave (DRW) established by Parker and Thorpe (1995) - lower troposphere - meso-scale 500km - moisture processes very important - rare phenomenon • Rossby-wave • - upper troposphere • synoptic-scale 2000km • - phenomenon of the dry • dynamics • ubiquitous phenomenon ≠ Maxi Böttcher

  3. intro Dynamics of the diabatic Rossby-wave (DRW) z x (Parker and Thorpe 1995) • low-level positive PV-anomaly over baroclinic zone; sufficient moisture • poleward ascending jet of warm air • diabatic heating → PV production downstream of the existent PV vortex Maxi Böttcher

  4. intro Dynamics of the diabatic Rossby-wave (DRW) z x (Parker and Thorpe 1995) • low-level positive PV-anomaly over baroclinic zone; sufficient moisture • poleward ascending jet of warm air • diabatic heating → PV production downstream of the existent PV vortex Maxi Böttcher

  5. intro Dynamics of the diabatic Rossby-wave (DRW) z x (Parker and Thorpe 1995) • low-level positive PV-anomaly over baroclinic zone; sufficient moisture • poleward ascending jet of warm air • diabatic heating → PV production downstream of the existent PV vortex Maxi Böttcher

  6. intro Dynamics of the diabatic Rossby-wave (DRW) Theoretical studies Snyder and Lindzen (1991) Parker and Thorpe (1995) Moore and Montgomery (2004, 2005) Case studies Wernli et al. (2002) Moore et al. (2008) DRW can lead to • explosive cyclogenesis • strong wind + heavy rain Maxi Böttcher

  7. data & tools Data & tools I ECMWF IFS analyses (T511L60) • interpolated on 0.6° hor. grid quasigeostrophic Omega diagnostic (Deveson et al. 2001, Dacre and Gray 2009) height-attributable solution of the Omega equation • Omega forced by lower levels 1000 – 750 hPa • Omega forced by upper levels 650 – 100 hPa Thanks to Sue Gray for providing the code! Maxi Böttcher

  8. data & tools Data & tools II COSMO model simulations • hor. res. 14 km, 40 vert. layers • non-hydrostatic • moist convection parameterized • initial and 6-hourly boundary data: ECMWF analyses • model output every hour Maxi Böttcher

  9. case & Ω Case overview & Ω-diagnostic 19 Dec 2005 00 UTC PV mean 975-800hPa SLP grey 2 pvu line at 250hPa blue Maxi Böttcher

  10. case & Ω Case overview & Ω-diagnostic 19 Dec 2005 00 UTC x PV mean 975-800hPa SLP grey 2 pvu line at 250hPa blue Ω at 700hPa lower-level red upper-level blue ascent solid – descent dotted Maxi Böttcher

  11. case & Ω Case overview & Ω-diagnostic 19 Dec 00 UTC 200 Pressure [hPa] 700 B A 1000 A B PV shaded meridional wind green latent heating black Ω at 700hPa lower-level red upper-level blue ascent solid – descent dotted Maxi Böttcher

  12. case & Ω Case overview & Ω-diagnostic 19 Dec 12 UTC PV mean 975-800hPa SLP grey 2 pvu line at 250hPa blue GOES east IR Maxi Böttcher

  13. case & Ω Case overview & Ω-diagnostic 19 Dec 12 UTC PV mean 975-800hPa SLP grey 2 pvu line at 250hPa blue Ω at 700hPa lower-level red upper-level blue ascent solid – descent dotted Maxi Böttcher

  14. case & Ω Case overview & Ω-diagnostic 20 Dec 00 UTC Ω at 700hPa lower-level red upper-level blue ascent solid – descent dotted PV mean 975-800hPa SLP grey 2 pvu line at 250hPa blue Start of explosive intensification Maxi Böttcher

  15. case & Ω Case overview & Ω-diagnostic 21 Dec 00 UTC Meteosat IR Pressure deepening of 34hPa/24h ! Maxi Böttcher

  16. COSMO COSMO control run performance 19 Dec 06 UTC COSMO/ECMWF ECMWF analysis track COSMO * ECMWF COSMO SLPmin DRW after 36h of COSMO run Maxi Böttcher

  17. COSMO COSMO sensitivity studies … moisture processes are important for DRW mechanism … • Where does the moisture come from? • What‘s the reaction of the DRW on moisture denial? EVAP suppressed ocean evaporation continuously in a stationary box HUM moisture is set to zero from the lowest model – 800hPa Maxi Böttcher

  18. COSMO COSMO - choise of the modification box 19 Dec 06 UTC 36h backward trajectories from the maximum of latent heating (CH > 20K/6h) Maxi Böttcher

  19. COSMO COSMO - choise of the modification box 19 Dec 06 UTC 36h backward trajectories from the maximum of latent heating (CH > 20K/6h) Maxi Böttcher

  20. COSMO COSMO - comparison of the sensitivity simulations CTL 19 Dec 06 UTC EVAP Maxi Böttcher

  21. COSMO COSMO - comparison of the sensitivity simulations CTL 19 Dec 06 UTC EVAP HUM Maxi Böttcher

  22. COSMO COSMO - comparison of the sensitivity simulations SLPmin [hPa] time CTL EVAP HUM DRW HUM new cyclone track SLPmin Maxi Böttcher

  23. conclusion Conclusion I • Diabatic Rossby-wave event with explosive intensification has been investigated • Quasigeostrophic Omega diagnostic demonstrates - absence of upper-level induced vertical motion during DRW propagation - intensification is triggered by superposition of lower and upper-level induced ascent Maxi Böttcher

  24. conclusion Conclusion II • COSMO model control simulation represents DRW development close to ECMWF analyses • COSMO sensitivity studies concerning the DRW moisture supply are performed by modifications in a box (moisture source region) - EVAP ocean surface evaporation in the vicinity of the DRW does not influence the propagation - HUM moisture withdrawal at low tropospheric levels to the south of the system kills the DRW Maxi Böttcher

More Related