1 / 66

Scale Interactions in Organized Tropical Convection

Scale Interactions in Organized Tropical Convection. George N. Kiladis Physical Sciences Division ESRL, NOAA. Why Study Tropical Convective Variability?. Tropical Convection acts as a primary “heat engine” for the atmospheric circulation

kali
Download Presentation

Scale Interactions in Organized Tropical Convection

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. Scale Interactions in Organized Tropical Convection George N. Kiladis Physical Sciences Division ESRL, NOAA

  2. Why Study Tropical Convective Variability? Tropical Convection acts as a primary “heat engine” for the atmospheric circulation Variability in tropical convection has global scale impacts over a variety of time scales Convection is coupled to the ocean within the tropics >Sea surface temperature has a strong influence >Atmospheric disturbances influence SST

  3. OBSERVATIONS OF WAVES WITHIN THE MJO Time–longitude diagram of CLAUS Tb (5S–equator), February 1987

  4. The Madden-Julian Oscillation (MJO) Discovered by Rol Madden and Paul Julian at NCAR in 1971 Characterized by an envelope of convection ~10,000 km wide moving eastward at around 5 m/s Most active over regions of high sea surface temperature (> 27 C) Can have a profound impact on the extratropical circulation Is poorly represented in general circulation models, if at all Composed of a variety of higher frequency, smaller scale disturbances

  5. Shallow Water System (Matsuno, 1966)

  6. Shallow Water System (Matsuno, 1966) is the meridional gradient of f at the eq where is the equivalent depth is the gravity wave speed

  7. Theoretical Dispersion Relationships for Shallow Water Modes on Eq.  Plane Frequency Zonal Wavenumber

  8. Theoretical Dispersion Relationships for Shallow Water Modes on Eq.  Plane Inertio-Gravity Kelvin Frequency Equatorial Rossby Zonal Wavenumber

  9. Kelvin Wave Theoretical Structure Wind, Pressure (contours), Divergence, blue negative

  10. Mixed Rossby-Gravity Wave Theoretical Structure Wind, Pressure (contours), Divergence, red negative

  11. Wavenumber-Frequency Spectral Analyis Decompose into Symmetric and Antisymmetric Fields about the Equator Complex Fourier Transform into wavenumber space at each latitude FFT of each wavenumber into frequency space Average the Power for each wavenumber/frequency by latitude Determine “background” spectrum by smoothing raw spectra Divide raw spectra by background spectra to determine signals standing above the background

  12. OLR power spectrum, 15ºS-15ºN, 1979–2001 (Symmetric) from Wheeler and Kiladis, 1999

  13. OLR power spectrum, 15ºS-15ºN, 1979–2001 (Symmetric) 1.25 Days Westward Power Eastward Power 96 Days from Wheeler and Kiladis, 1999

  14. OLR power spectrum, 15ºS-15ºN, 1979–2001 (Antisymmetric) from Wheeler and Kiladis, 1999

  15. OLR background spectrum, 15ºS-15ºN, 1979–2001 from Wheeler and Kiladis, 1999

  16. OLR power spectrum, 1979–2001 (Symmetric) from Wheeler and Kiladis, 1999

  17. OLR power spectrum, 1979–2001 (Symmetric) Westward Inertio-Gravity Kelvin Equatorial Rossby Madden-Julian Oscillation from Wheeler and Kiladis, 1999

  18. OLR power spectrum, 1979–2001 (Antisymmetric) from Wheeler and Kiladis, 1999

  19. OLR power spectrum, 1979–2001 (Antisymmetric) Eastward Inertio-Gravity Mixed Rossby-Gravity from Wheeler and Kiladis, 1999

  20. MJO (5 m s-1) OBSERVATIONS OF KELVIN WAVES AND THE MJO Time–longitude diagram of CLAUS Tb (2.5S–7.5N), January–April 1987 Kelvin waves (15 m s-1)

  21. OBSERVATIONS OF KELVIN AND MRG WAVES Time–longitude diagram of CLAUS Tb (2.5S–7.5N), May 1987

  22. 1998 Brightness Temperature 5ºS-5º N

  23. Kelvin Wave Theoretical Structure Wind, Pressure (contours), Divergence, blue negative

  24. OLR power spectrum, 1979–2001 (Symmetric) from Wheeler and Kiladis, 1999

  25. Regression Models Simple Linear Model: y = ax + b where: x= predictor (filtered OLR) y= predictand (OLR, circulation)

  26. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day 0 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  27. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day-6 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  28. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day-5 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  29. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day-4 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  30. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day-3 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  31. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day-2 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  32. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day-1 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  33. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day 0 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  34. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day+1 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  35. OLR and 1000 hPa Flow Regressed against Kelvin-filtered OLR (scaled -20 W m2) at 10N, 150W for June-Aug. 1979-2004 Day+2 Geopotential Height (contours 2 m) Wind (vectors, largest around 5 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  36. Mixed Rossby-Gravity Wave Theoretical Structure Wind, Pressure (contours), Divergence, red negative

  37. OLR and 850 hPa Flow Regressed against MRG-filtered OLR (scaled -40 W m2) at 7.5 N, 172.5E, 1979-2004 Day-1 Streamfunction (contours 2 X 105 m2 s-1) Wind (vectors, largest around 2 ms-1) OLR (shading starts at +/- 6 W s-2), negative blue

  38. Temperature Structure of a Dry Kelvin Wave Direction of Motion W C W C

  39. Temperature Structure of a Dry Kelvin Wave Direction of Motion W C W C

  40. Temperature at Majuro (7N, 171E) Regressed against Kelvin-filtered OLR (scaled -40 W m2) for 1979-1999 OLR (top, Wm-2) Temperature (contours, .1 °C), red positive from Straub and Kiladis 2002

  41. Zonal Wind at Majuro (7N, 171E) Regressed against Kelvin-filtered OLR (scaled -40 W m2) for 1979-1999 OLR (top, Wm-2) Zonal Wind (contours, .25 ms-1), red positive from Straub and Kiladis 2002

  42. Specific Humidity at Majuro (7N, 171E) Regressed against Kelvin-filtered OLR (scaled -40 W m2) for 1979-1999 OLR (top, Wm-2) Specific Humidity (contours, 1 X 10-1 g kg-1), red positive from Straub and Kiladis 2002

  43. Meridional Wind at Majuro (7N, 171E) Regressed against MRG-filtered OLR (scaled -40 W m2) for 1979-1999 OLR (top, Wm-2) Meridional Wind (contours, .25 ms-1), red positive

  44. Temperature at Majuro (7N, 171E) Regressed against MRG-filtered OLR (scaled -40 W m2) for 1979-1999 OLR (top, Wm-2) Temperature (contours, .1 °C), red positive

  45. Specific Humidity at Majuro (7N, 171E) Regressed against MRG-filtered OLR (scaled -40 W m2) for 1979-1999 OLR (top, Wm-2) Specific Humidity (contours, 1 X 10-1 g kg-1), red positive

  46. Wave Motion Haertel and Kiladis 2004

  47. Wave Motion Haertel and Kiladis 2004

  48. Wave Motion Haertel and Kiladis 2004

  49. Wave Motion Haertel and Kiladis 2004

  50. Zonal Wind at Honiara (10S, 160E) Regressed against MJO-filtered OLR (scaled -40 W m2) for 1979-1999 OLR Pressure (hPa) OLR (top, Wm-2) U Wind (contours, .5 ms-1), red positive from Kiladis et al. 2005

More Related