1 / 50

The Tropical Cloud Population

This lecture explores the different types of tropical clouds, including severe convection and mesoscale systems, and discusses the distribution and dynamics of the tropical cloud population. It also explores the relationship of these clouds to large-scale weather systems, monsoon convection, diurnal variability, and tropical cyclones. The research is supported by NASA, NSF, and DOE grants.

michellemartinez
Download Presentation

The Tropical Cloud Population

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. The Tropical Cloud Population R. A. Houze Lecture, Indian Institute of Tropical Meteorology, Pune, 9 August 2010

  2. Clouds in Low Latitudes Lecture Sequence • Basic tropical cloud types • Severe convection & mesoscale systems • Tropical cloud population • Convective feedbacks to large-scales • Monsoon convection • Diurnal variability • Clouds in tropical cyclones

  3. Before Satellites

  4. Visual Observation Cumulonimbus and mesoscale convective systems Cumulus congestus Small cumulus View from an aircraft flying over the South China Sea

  5. Radiosonde Data “Hot tower hypothesis” of Riehl & Malkus 1958

  6. Satellite Observations

  7. Large cloud shields

  8. Large cloud shields

  9. Circa 1970 Satellite view of the tropical cloud population • Not good: • Missing downdraft • No stratiform rain • Unrealistic scale separation • Good: • Explained satellite pictures • Retained the hot tower notion • Included smaller clouds

  10. Radars

  11. GATE 1974

  12. GATE SHIP ARRAY

  13. More Field Projects to Study Convection BoB 1979 JASMINE1999 EPIC 2001 TEPPS1997 (Dashed: No sounding network)

  14. Post-GATE view of the tropical cloud population MESOSCALE CONVECTIVE SYSTEMS (MCSs) STRATIFORMRAIN Houze et al. (1980)

  15. By the early 1980’s Idealized life cycle of tropical MCS Houze 1982

  16. Precipitation Radar in Space

  17. The TRMM Satellite TRMM Radar Low altitude, low inclination orbit

  18. TRMM Satellite Instrumentation λ= 2 cm Important! PR measures 3D structure of radar echoes Kummerow et al, 1998

  19. Knowledge of global rainfall before satellites measured rain from space

  20. Knowledge of global rainfall after TRMM & other satellites measured rain from space Combined satellite rainfall July 2000 TRMM plus passive microwave sensors + other

  21. How is tropical rain distributed by cloud size and type?

  22. 2 Years of TRMM PR data Large CbsMCSs Smallisolated Cbs Schumacher & Houze 2003

  23. How do the environments of these regimes differ?

  24. Trade Wind Regime

  25. Stratocumulus Regime

  26. Trade Wind Regime

  27. Indo/Pacific Warm Pool

  28. Traditional conceptual view of mean meridional distribution of tropical convection Simpson 1992

  29. “Trimodal” distributionJohnson et al. 1999Conceptual model based on TOGA COARE observations Cu congestus Small Cb

  30. “Trimodal” distributionJohnson et al. 1999Evidence from TOGA COARE soundingdata

  31. MANUS X “Trimodal” distributionHollars et al. 1999Evidence from Manus ARM cloud radar observations

  32. Tropical cloud population related to SST

  33. TRMM PR Deep Convective SST Climatology (July) July SST TRMM PR Shallow, Isolated Convective

  34. Land vs Ocean

  35. TRMM view of Africa vis a vis the Atlantic Rain Stratiform Rain Fraction MCSs with large 85GHz ice scattering Lightning

  36. Cloud Radar in Space

  37. Anvils of Mesoscale Convective Systems (MCSs) Yuan and Houze 2010

  38. Three steps of analysis of multi-sensor data 1 2 3 & (TB11) (GEOPROF-2B) (TB11) (GEOPROF-2B) Yuan and Houze 2010

  39. Use MODIS and CloudSat to find threshold of thick high cloud MODIS MODIS CloudSat Yuan and Houze 2010

  40. 1-Find“cold centers” 2-Use AMSR-E to find rain areas Locate 1st closed contour Use 260 K threshold Associate pixels with nearest cold center Use 1 mm/h threshold for rain rate Yuan and Houze 2010

  41. Define criterion for MCS that is reasonable for all these regions Yuan and Houze 2010

  42. Colors show rain amount Temperature defining cold center TB11 = 220 Area > 2000 km2 account for most of the rainfall Size of cold cloud top Yuan and Houze 2010

  43. “Connected” and “Separated” MCSs Yuan and Houze 2010

  44. MCSs Over the Whole Tropics Yuan and Houze 2010

  45. MCSs Over the Whole Tropics Yuan and Houze 2010

  46. Frequency of MCS anvils over tropics Yuan and Houze 2010

  47. Comparison of MCS anvils in different parts of the tropics CloudSat data Yuan and Houze 2010

  48. Milestones in determining the tropical cloud population Pre-satellite eraHot towers and smaller clouds Radars in field projectsMCSs, squall lines, stratiform precipitation Precipitation radar in spacePatterns of convective, stratiform, shallow isolatedRelation to ocean & land Cloud radar in spaceGlobal distributions of MCSs & anvils

  49. Clouds in Low Latitudes Lecture Sequence • Basic tropical cloud types • Severe convection & mesoscale systems • Tropical cloud population • Convective feedbacks to large-scales • Monsoon convection • Diurnal variability • Clouds in tropical cyclones Next

  50. This research was supported by NASA grants NNX07AD59G, NNX07AQ89G, NNX09AM73G, NNX10AH70G, NNX10AM28G, NSF grants, ATM-0743180, ATM-0820586, DOE grant DE-SC0001164 / ER-6

More Related