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Cyclone Classification:  Internal Structure versus Energetics - An aplication to the Catarina Event. . Pedro Leite da Silva Dias National Laboratory of Scientific Computing Ministry of Science and Technology Institute of Astronomy, Geophysics and Atmospheric Sciences

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Cyclone Classification:  Internal Structure versus Energetics - An aplication to the Catarina Event.

Pedro Leite da Silva Dias

National Laboratory of Scientific Computing

Ministry of Science and Technology

Institute of Astronomy, Geophysics and Atmospheric Sciences

University of São Paulo (USP)

Lll

Encontro internacional sobre ciclones do atlântico sul, previsão de trajetórias e avaliação de riscos

Rio de Janeiro, 19 a 21 de maio de 2008


Classical view: Energetics - An aplication to the Catarina Event.


But, on March 28 2004 ….. Energetics - An aplication to the Catarina Event.


03 UTC Energetics - An aplication to the Catarina Event. 22 March

15 UTC 22 March

03 UTC 23 March

15 UTC 23 March

03 UTC 24 March

15 UTC 24 March

03 UTC 25 March

15 UTC 2 March

0/ UTC 26 March

15 UTC 26 March

15 UTC 27 March

15 UTC 28 March

From Gan and Rao 2006

Pezza and Simmonds, 2005


Produced by J. Conrado) Energetics - An aplication to the Catarina Event.


Produced by J. Conrado) Energetics - An aplication to the Catarina Event.


Produced by J. Conrado) Energetics - An aplication to the Catarina Event.


Produced by J. Conrado) Energetics - An aplication to the Catarina Event.


Produced by J. Conrado) Energetics - An aplication to the Catarina Event.


Produced by J. Conrado) Energetics - An aplication to the Catarina Event.


Produced by J. Conrado) Energetics - An aplication to the Catarina Event.


How about satellite derived precipitation? Energetics - An aplication to the Catarina Event.


GOES/TRMM Energetics - An aplication to the Catarina Event.

(R.Gevaerd


27 March 2004 11 Z Energetics - An aplication to the Catarina Event.

5-8km


Vertical structure Energetics - An aplication to the Catarina Event.


Relative humidity - shaded Energetics - An aplication to the Catarina Event.

Potential temperature (isolines)

From Bonatti et al. 2006

Q


From Bonatti et al. 2006 Energetics - An aplication to the Catarina Event.

Relative humidity - shaded

Potential temperature (isolines)

Q

F

F


From Bonatti et al. 2006 Energetics - An aplication to the Catarina Event.

Relative humidity - shaded

Potential temperature (isolines)


Vertical Structure - FSU Energetics - An aplication to the Catarina Event.

http://www.moe.met.fsu.edu

Low troposphere vertical shear (warm x cold core)

Upper troposphere vertical shear

symmetry

Hart 2003 - Cyclone Phase


upper Energetics - An aplication to the Catarina Event.

troposphere

AVN – ANALYSIS

lower troposphere


upper Energetics - An aplication to the Catarina Event.

troposphere

CIRA AMSU retrieval

lower troposphere


Cross section at 29.3S Energetics - An aplication to the Catarina Event.

00Z28Mar2004

Q1

EYE

Q2

EYE

NCEP – High resolution GFS analysis

50km


Surface Energetics - An aplication to the Catarina Event. Fluxes


Sensible Heat Flux Anomaly Energetics - An aplication to the Catarina Event.

Surface


Latent Heat Flux Anomaly Energetics - An aplication to the Catarina Event.

Surface



162 h 136h 114h

CPTEC ETA forecast at 06 UTC 28 Mar 2004


90 h 66h 42h

CPTEC ETA forecast at 06 UTC 28 Mar 2004



Brams
BRAMS 42h

  • Version 3.0

    • Based on RAMS 5.04

    • Maintained by CPTEC

    • Particular features:

      • Shallow Cumulus Parameterization

      • Deep cumulus parametrization – “Grell-Ensemble”

      • Initialization of soil moisture

      • Option for surface processes: LEAD and SIB2 (with Carbon)

      • Surface data assimilation with internal quality control

      • CATT – dispersion module for gases and aerosols produced by biomass burning and urban sources

  • 2 grids: 32 km and 8 km (with cloud microphysics)

    • Previous experiments by Menezes et al. 2004- CBMET



Warm pools detached from Brazil Current are common but this one can’t be tracked …

This warm area may be important..

SST Anomalies – High Resolution data -20km


Effect of high one can’t be tracked …

Resolution SST:

less intense system !!!!

See Renato Silva 2004 -XIIICBMet


Impact of perturbation in the latent heating vertical profile

Geopotential tendency is proportional to the vertical derivative of the diabatic heating





Summary
Summary profile

  • Do tropical cyclones belong to a unique family?

  • OR are we artificially separating a continuum of atmospheric vortices into groups?

  • In Australia: subtropical lows with hurricane intensity winds


ENERGETICS profile

Brennan e Vincent (1980)


Cyclone tracking: profile

At each time, energetics at the box is computed





This is the previous cyclone yesterday .ppt Catarina

Note large baroclinic conversion and increase of Ke

Small contribution of Q’T

Increase of Ke also related to barotropic conversion


Ciclone off the S coast of Brazil - 13/Feb/2008 Catarina

Initial phase is typically baroclonic

Latent heat picks up later…

Strong energy conversion

Barotropic conversion from Ke to Kz except at the end





Small Q Catarina’T

Typical barocliniic conversion

Ke->KZ



Conceptual view of the energetics Catarina

Bomb cyclone

Hurricane

Q’T’

most

Few (hybrid)

Tropical storms

baroclinic

V’T’dU/dy

AZ ->AE

barotropic

u’v’dU/dy KZ -> KE


Conclusions- I Catarina

  • Vertical profile of diabatic heating in operational models is too high: global and regional

  • Downscaling also lead to heating at higher levels: not enough pressure drop at low levels and therefore models underestimated the wind speed;

  • Perturbations in the vertical heating profile lead to intensification of the system: in one case the trajectory was substantially changed – the low pressure veered to the north and eventually reached the Rio de Janeiro coast

  • Energetics: early phase follows typical evolution of cold moist baroclinic perturbation. Later phase: barotropic conversion + moist conversion (not large).Hybrid system –subtropical low with hurricane intensity (1) at the end.


  • Recommendations Catarina

  • Need objective classification system for hybrid systems such as Catarina: energetics is a possible choice;

  • The workshop organized by the Brazilian Meteorological Society recommended that in spite of the hybrid structure of the cyclone, if another case arises in the future, it is recommended that the systems be called “hurricane” when the estimated wind speed falls in the category I. This recommendation is based on the fact that the public perception that this type of event is significantly different from the regular extratropical and subtropical lows that regularly reach the southern part of Brazil

  • Articulated solution with WMO should be sought in order to improve classification of cyclones (according to the WMO manual: hurricanes are non frontal structures…) , personnel training and dissemination of the information. - IWTC Costa Rica Nov. 2006


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