intro data & tools case & Ω COSMO conclusion A case study of an explosively deepening diabatic Rossby-wave induced cyclone: the influence of environmental conditions Maxi Böttcher and Heini.
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intro data & tools case & Ω COSMO conclusion 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 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion What‘s a diabatic Rossby-wave? Diabatic Rossby wave (DRW) Rossby-wave established by Parker and Thorpe (1995) - upper troposphere - synoptic-scale 2000km ≠ - lower troposphere - meso-scale 500km - phenomenon of the dry dynamics - moisture processes very important - ubiquitous phenomenon - rare phenomenon 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion 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 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion 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 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion 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 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion Dynamics of the diabatic Rossby-wave (DRW) Theoretical studies Case studies Snyder and Lindzen (1991) Parker and Thorpe (1995) Moore and Montgomery (2004, 2005) Wernli et al. (2002) Moore et al. (2008) DRW can lead to • explosive cyclogenesis • strong wind + heavy rain 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion 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! 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion 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 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion Case overview & Ω-diagnostic 19 Dec 2005 00 UTC PV mean 975-800hPa SLP grey 2 pvu line at 250hPa blue 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion Case overview & Ω-diagnostic 19 Dec 2005 00 UTC x PV mean 975-800hPa SLP grey 2 pvu line at 250hPa blue 16 Sept 2009 Ω at 700hPa lower-level red upper-level blue ascent solid – descent dotted Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion Case overview & Ω-diagnostic 19 Dec 00 UTC Pressure [hPa] 200 700 B A 1000 A PV shaded meridional wind green latent heating black B 16 Sept 2009 Maxi Böttcher Ω at 700hPa lower-level red upper-level blue ascent solid – descent dotted University Mainz, Germany intro data & tools case & Ω COSMO conclusion Case overview & Ω-diagnostic 19 Dec 12 UTC PV mean 975-800hPa SLP grey 2 pvu line at 250hPa blue 16 Sept 2009 GOES east IR Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion Case overview & Ω-diagnostic 19 Dec 12 UTC PV mean 975-800hPa SLP grey 2 pvu line at 250hPa blue 16 Sept 2009 Ω at 700hPa lower-level red upper-level blue ascent solid – descent dotted Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion Case overview & Ω-diagnostic 20 Dec 00 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 Start of explosive intensification 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion Case overview & Ω-diagnostic 21 Dec 00 UTC Meteosat IR Pressure deepening of 34hPa/24h ! 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion COSMO control run performance 19 Dec 06 UTC COSMO/ECMWF ECMWF analysis track COSMO COSMO * ECMWF SLPmin DRW after 36h of COSMO run 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion COSMO sensitivity studies … moisture processes are important for DRW mechanism … 1. 2. 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 16 Sept 2009 moisture is set to zero from the lowest model – 800hPa Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion COSMO - choise of the modification box 19 Dec 06 UTC 36h backward trajectories from the maximum of latent heating (CH > 20K/6h) 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion COSMO - choise of the modification box 19 Dec 06 UTC 36h backward trajectories from the maximum of latent heating (CH > 20K/6h) 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion COSMO - comparison of the sensitivity simulations CTL 19 Dec 06 UTC EVAP 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion COSMO - comparison of the sensitivity simulations CTL 19 Dec 06 UTC EVAP 16 Sept 2009 HUM Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO conclusion SLPmin [hPa] COSMO - comparison of the sensitivity simulations time track 16 Sept 2009 CTL EVAP HUM DRW HUM new cyclone Maxi Böttcher SLPmin University Mainz, Germany intro data & tools case & Ω COSMO 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 16 Sept 2009 Maxi Böttcher University Mainz, Germany intro data & tools case & Ω COSMO 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 16 Sept 2009 Maxi Böttcher University Mainz, Germany