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Global Trends in the Earth's Climate from Recent Observations

Global Trends in the Earth's Climate from Recent Observations. Yuk Ling Yung ( 翁玉林） Caltech. Seminar at NTU ROC 18 July 2012. Dr. Liang Mao-Chang (AS). Professor Jiang Xun (UH). 3. Overview. Part 1. Changes in the Hydrological Cycle Water Vapor and Precipitation Theory

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Global Trends in the Earth's Climate from Recent Observations

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  1. Global Trends in the Earth's Climate from Recent Observations Yuk Ling Yung (翁玉林） Caltech Seminar at NTU ROC 18 July 2012

  2. Dr. Liang Mao-Chang (AS) Professor Jiang Xun (UH) 3

  3. Overview • Part 1. Changes in the Hydrological Cycle • Water Vapor and Precipitation • Theory • Part 2. Decadal Record by Aqua over the Tropics • Mode Decomposition (Huang-Hilbert Transform) • Trends

  4. Hydrological Cycle Project Collaborators: Jiang Xun, Li Liming (UH) Li et al. 2011 ERL Aqua Temperature Project Collaborators: Shi Yuan, Li King Fai, T. Hou, H. Aumann (Caltech, JPL) Shi et al. 2012 Climate Dynamics

  5. A-Train 3-D Aerosols Aerosol polarization 3-D Clouds Aerosol polarization AIRS – T, P, H2O, CO2, CH4 MODIS – clouds, aerosols, albedo CO2 ps, clouds, aerosols TES – T, P, H2O, O3, CH4, CO MLS – O3, H2O, CO OMI – O3 • 705 km altitude sun synchronous, 98.2 inclination, 98.8 minute period • Global coverage with a 16-day(233 orbit) ground track repeat cycle

  6. Courtesy Brian Soden

  7. Courtesy Brian Soden

  8. Gross view of the changing water cycle ~2%/K ~7%/K Courtesy Frank Li (李瑞麟) + Graeme Stephens et al. 2012

  9. What Do The Data Tell Us? I) Precipitation GPCP (V2.1) 2.5º× 2.5º monthly precipitation (1979-2009) SSM/I (V6) 0.25º× 0.25º monthly precipitation (1988-2009) TRMM (V6) 0.25º× 0.25º monthly precipitation (1998-2011) II) Water vapor SSM/I (V6) 0.25º× 0.25º monthly Water Vapor (1988-2009) AIRS (V5) and AMSR (V5) 1º× 1º monthly Water Vapor (2002-2009) NVAP 1º× 1º monthly Water Vapor (2002-2009)

  10. Precipitation and Water Vapor ΔP (mm/mon) ΔW (mm/mon) • Deseasonalized time series of oceanic precipitation from GPCP V2.1 and SSM/I. • Deseasonalized time series of oceanic water vapor from SSM/I, AIRS, AMSR-E, and NVAP.

  11. Trends in Precipitation and Water Vapor Deseasonalized & Lowpass Filtered Timeseries SSM/I+GPCP: 0.26 ± 0.41 %/decade GPCP: 0.08 ± 0.43 %/decade SSM/I: 1.01 ± 0.39 %/decade [Li et al., ERL 2011] Weak linear trend in precipitation is much smaller than the linear trend (1.4 ± 0.5% per decade) in the previous study (Wentz et al., 2007).

  12. Trends in Oceanic Precipitation, Water Vapor, and Recycling Rates Deseasonalized & Lowpass Filtered Timeseries SSM/I: 0.13 ± 0.63 %/decade GPCP: 0.33 ± 0.54 %/decade SSM/I: 0.97 ± 0.37 %/decade Recycling 1 = (SSM/I P)/(SSM/I W) Recycling 1: -0.82 ± 1.11 %/decade Recycling 2: -0.65 ± 0.51 %/decade Recycling 2 = (GPCP P)/(SSM/I W) ENSO Signals have been removed by a multiple regression method.

  13. Precipitation and Water Vapor

  14. Spatial Pattern of the Mean Precipitation for 1988-2008

  15. Temporal Variations of Precipitation over High & Low Precipitation Areas

  16. 50-year obs Figure 3. Patterns of 50-year surface salinity change (PSS-78 50yr-1). A) The 1950-2000 observational result of Durack & Wijffels (2010). B) From an ocean model forced with an idealised surface 5% E-P enhancement (50 yr-1; see text). C) For an ensemble mean from 1950-2000 of the CMIP3 20C3M simulations which warm less than <0.5°C (24 simulations). D) For an ensemble mean from 1950-2000 of the CMIP3 20C3M simulations which warm greater than >0.5°C (26 simulations). In each panel, the corresponding mean salinity from each representative data source is contoured in black, with thick lines every 1 (PSS-78) and thin lines every 0.5 (PSS-78). From Durack et al., 2012

  17. Mechanisms of tropical precipitation changes Chou et al. 2009

  18. Connection to energy balance The DLR response to climate warming is the dominant factor in the response of the atmospheric radiative cooling to this warming. Thus precipitation change is set by the change in water vapor (a consequence of the water vapor feedback but does not keep pace with the increases in vapor Stephens & Hu, 2010 ERL Courtesy Graeme Stephens

  19. Conclusions Trend in the global precipitation is smaller than the trend in the global water vapor. 2) Precipitation has increased in the ITCZ and decreased in the neighboring regions over the past two decades.

  20. Overview • Part 1. Changes in the Hydrological Cycle • Water Vapor and Precipitation • Theory • Part 2. Decadal Record by Aqua over the Tropics • Mode Decomposition (Huang-Hilbert Transform) • Trends

  21. Motivation What are the Natural Variabilities? How do we separate them from the Trend?

  22. Advanced Microwave Sounding Unit (AMSU)

  23. Raw data

  24. Channel 5

  25. Imf 6

  26. Channel 9

  27. Channel 14

  28. Imf 5 QBO

  29. Annual and Semi-annual Cycles

  30. Seasonal Cycle

  31. SAO

  32. QBO

  33. Trends

  34. Trend

  35. Liang et al. 2012

  36. Near Annual (18 mon)

  37. Near Annual Mode

  38. Conclusions • All natural modes found and separated, no spurious modes • Discovered a new mode ~18 mon • Decadal trends are significant, probably due to couple Ocean-Atmosphere interaction

  39. Acknowledgements • Yung’s Group at Caltech • Jiang Xun (UH) • Shi Yuan (HKU, Caltech, Princeton) • Liang Mao-Chang (RCEC) • NSF/NASA/JPL

  40. 49

  41. Backup Slides

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