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WV images, Potential Vorticity and Conceptual Models Nuno Moreira Instituto de Meteorologia, Lisboa, Portugal 2003.

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Presentation on theme: "WV images, Potential Vorticity and Conceptual Models Nuno Moreira Instituto de Meteorologia, Lisboa, Portugal 2003."— Presentation transcript:

1 WV images, Potential Vorticity and Conceptual Models Nuno Moreira Instituto de Meteorologia, Lisboa, Portugal 2003

2 W V images - Characteristics n Water Vapour absorption band : –WV Meteosat channel –WV 6.2 ( ) from MSG –WV 7.3 (6.85 – 7.85 ) from MSG n Water vapour absorbes Infra-Red radiation emmited by the earth surface and lower clouds n WV image is “constructed” from the re-emission by water vapour

3 W V images - Characteristics n “The instrument measures the humidity temperature” n “Topography of water vapour emission” n Gray shades –Light gray – humidity in the troposphere upper levels –Dark gray - humidity in the troposphere lower levels

4 Regions of emission n R.H. =100% -> 250 hPa hPa (max: 350 hPa) n R.H. = 50% -> 250 hPa hPa (max: 400 hPa) n R.H, = 25% -> 250 hPa hPa (max: 450 hPa) (Bader et al, 1995)

5 Regions of emission n Bader et al (1995)

6 Water Content in the troposphere n 48.7 % of total water content – below 850hPa n 77.5% of total water content - below 700hPa n 92.5% of total water content - below 550hPa (NOAA, 1991)

7 W V Image and tropospheric levels n Light areas – white / light gray –Humidity in upper levels –Medium and lower levels ? n Dark areas – black/ dark gray –Low humidty in upper levels –Higher humidity content in medium levels –Lower levels ?

8 And a Water Vapour Image...

9 … filter in “whiter shading” … filter in “whiter shading”

10 Fenomena retrieved from water vapour imagery n Tropopause folding n Jet streams/streaks n Vorticity Advection n Rapid cyclogenesis (bombs) (?) n Troughs and ridges in upper levels n Cut-off lows

11 Related meteorological parameters n Geopotential (eg. 300 hPa) n Wind field (eg. 300 hPa) n Potencial Vorticity n Tropopause Map

12 Potential Vorticity n Potential Vorticidade in isentropic levels (constant potential temperature ) n Absolute Vorticity (planetary + relative) and static stability n Tropospheric air mass – low (I)PV n Stratospheric air mass – high (I)PV

13 Potential Vorticity n Dynamic Tropopause = UVP n Advantages of Isentropic Potential Vorticity (IPV) –Conservative property over a conservative surface –Superposition with wind field depicts temporal evolution of Potential Vorticity n However, PV can also be depicted in pressure levels !!

14 Tropopause Map n Topography of the Tropopause (isentropic coordenates, isobaric, geopotencial) n low -> low Tropopause n high -> high Tropopause n Advantage –Quantifies lowest tropopause level

15 PV ----> Tropopause Map

16 Conceptual Models Jet Stream

17 The definiton … n Jet stream – Upper Tropospheric wind speed > 60 kt n Jet streak (= Jet Stream maximum) –“wind speed maximum situated along the axis of a jet stream at the level of maximum wind” (Palmén and Newton, 1969)

18 Jet Stream – vertical section n Keyser and Shapiro (1986)

19 Jet Stream – vertical section n Holton (1992)

20 Jet Stream – vertical section n Met. Office (1997)

21 Jet  Relative Vorticity n “Manual of Synoptic Satellite Meteorology–Conceptual Models, v3.0”, ZAMG/KNMI/FMI/EUMETSAT North H.: cyclonic side – Positive Relative Vorticity South H. : cyclonic side – Negative Relative Vorticity

22 Jet  Vorticity advections n “Manual of Synoptic Satellite Meteorology–Conceptual Models v3.0”, ZAMG/KNMI/FMI/EUMETSAT PVA- Positive Vorticity Advection NVA - Negative Vorticity Advection

23 Jet  Ageostrophic Wind  Vertical motion n Keyser and Shapiro (1986)

24 Jets and Fronts n Bluestein (1993)

25 Conceptual Models Tropopause Foldings

26 Cut-off lows n Elizaga et al (1996)

27 Lowering Tropopause ----> Vertical Motion n Elbern et al (1998) 15Oct93

28 Lowering Tropopause ----> Vertical Motion n Romero (2000) 28 Sep 94

29 Conceptual Models (rapid) Cyclogenesis

30 Hoskins et al (1985)

31 Boyle and Bosart (1986)

32 Hirschberg and Fritsch (1991)

33 n Malardel (2000) And...

34 .. Related NEW proposed symbols.... Related NEW proposed symbols.. n Adapted from Joly and Santurette (2000)

35 References n n Bader, M.J., Forbes, G.S., Grant, J.R., Lilley, R.B. e Waters, A.J., 1995: Images in weather forecasting. Cambridge University Press, Cambridge, 499 pp. n n Bechtold, P., 2000: Atmospheric moist convection: effects, concepts and modelling/forecast. Módulo do Curso “Weather forecasting in the midlatitudes” realizado na MeteoFrance de 4-15 Dezembro 2000 [ver relatório VAP01/01, Instituto de Meteorologia] n n Bluestein, H.B., 1993: Synoptic-Dynamic Meteorology in Midlatitudes, Vol.II: Observations and Theory of Weather Systems. Oxford University Press, Oxford, 594 pp. n n Boyle, J.S. e Bosart, L.F., 1986: Cyclone-Anticyclone couplets over North America. Part II: Analysis of a major cyclone event over the Eastern United States. Mon. Wea. Rev., 114, n n Elbern, H., Hendricks, J. e Ebel, A., 1998: A climatology of tropopause folds by global analysis. Theor. Appl. Climatology, 59, n n Elizaga, F., Martin, F., Riosalido R., Carretero, O., Elvira, B. e Garcia, A., 1996: Imágenes de vapor de agua: uso en el diagnostico de niveles altos. IV Simposio Nacional de Predección. Memorial “Alfondo Ascaso”, Madrid, Abril 1996, INM. n n Grahame, N., 1998: Christmas Eve storm. Review of interesting synoptic cases. Fourth Meeting of the Working Group on Cooperation between European Forecasters (WG CEF). Set. 98 Comunicação oral. n n Hirschberg, P.A. e Fritsch, J.M., 1991b: Tropopause ondulations and the development of extratropical cyclones - Part II: Diagnostic Analysis and coceptual model. Mon. Wea. Rev., 119, n n Hoskins, B.J., McIntyre, M.E. e Robertson, A.W., 1985: On the use and significance of isentropic potencial vorticity maps. Quart. J. Roy. Meteo. Soc., 111, n n Joly, A e Santurette, P., 2000: Turning dynamical ideas into forecast practice: a proposal for a renewed graphic summary of the synoptic scale situation. Centre National de Recherches Météorologiques, Service Central d´Exploitation Météorologique. Módulo do Curso “Weather forecasting in the midlatitudes” realizado na MeteoFrance de 4-15 Dezembro 2000 [ver relatório VAP01/01, Instituto de Meteorologia]

36 References n n Keyser, D. e Shapiro, M.A., 1986: Review – A review of the structure and dynamics of upper-level frontal zones. Mon. Wea. Rev., 114, n n Malardel, S., 2000: Weather forecasting in midlatitudes regions - Large scale dynamics in the midlatitudes. Módulo do Curso “Weather forecasting in the midlatitudes” realizado na MeteoFrance de 4-15 Dezembro 2000 [ver relatório VAP01/01, Instituto de Meteorologia] n n Moreira, N., 1999: Utilização de imagens de vapor de água na avaliação de campos previstos por Modelos numéricos. Instituto de Meteorologia. n n Morgan,M.C. e Nielson-Gammon, 1998: Using tropopause maps to diagnose midlatitude weather systems. Mon. Wea. Rev., 126, n n NOAA, 1991: Water vapor imagery – Interpretation and applications to weather analysis and forecasting. NOAA Technical report NESDIS 57, National Oceanic and Atmospheric Admnistration, Washington, 213 pp. n n Prates, F., 1996: Utilização de cartas de vorticidade potencial isentrópica no diagnóstico dos processos de ciclogénese. Nota Técnica. Instituto de Meteorologia. n n Romero, R., 2000: Sensitivity of a heavy rain producing Western Mediterranean cyclone to embedded potencial vorticity anomalies. Submetido ao Quarterly Journal of the Royal Meteorological Society. n n Santurette, P., 1998: About new products and new methods for synoptic forecast in Meteo-France. Casos de estudo apresentados no curso sobre previsão na Meteo-France, Dez. 98. Comunicação oral. n ZAMG/KNMI/FMI/EUMETSAT, 2001: Manual of Synoptic Satellite Meteorology – Conceptual Models v3.0.


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