First-Order Draft Chapter 3 IPCC WG1 Fourth Assessment Report 1 2 Chapter 3: Observations: Surface and Atmospheric Climate Change 3 4 Coordinating Lead Authors: Philip D. Jones, Kevin E. Trenberth 5 6 Lead Authors: Peter G. Ambenje, Roxana Bojariu, David R. Easterling, Albert M. G. Klein Tank, David E. 7 Parker, James A. Renwick, Fatemeh Rahimzadeh, Matilde M. Rusticucci, Brian J. Soden, Pan-Mao Zhai 8 9 Contributing Authors: R. Adler, L. Alexander, H. Alexandersson, R. P. Allan, M. P. Baldwin, M. 10 Beniston, D. H. Bromwich, I. Camilloni, C. Cassou, D. R. Cayan, E. K. M. Chang, J. R. Christy, A. Dai, C. 11 Deser, N. Dotzek, R.L. Fogt, C. K. Folland, P. Forster, M. Free, C. Frei, B. Gleason, J. Grieser, P. Y. 12 Groisman, S. K. Gulev, J. W. Hurrell, M. Ishii, S. A. Josey, P. W. Kållberg, G. N. Kiladis, R.H. Kripalani, K. 13 E. Kunkel, C-Y. Lam, J. R. Lanzante, J. H. Lawrimore, D. H. Levinson, B. G. Liepert, G. J. Marshall, C. A. 14 Mears, P. W. Mote, H. Nakamura, N. Nicholls, J. R. Norris, T. Oki, F. R. Robinson, K. Rosenlof, F. H. 15 Semazzi, D. J. Shea, J. M. Shepherd, T. G. Shepherd, S. C. Sherwood, A. J. Simmons, I. Simmonds, P. C. 16 Siegmund, C. D. Thorncroft, P. D. Thorne, S. M. Uppala, R. S. Vose, B. Wang, S. G. Warren, R. 17 Washington, M. C. Wheeler, B. A. Wielicki, T. Wong. 18 19 Review Editors: Brian J. Hoskins, Bubu P. Jallow, Tom R. Karl 20 21 Date of Draft: 12 August 2005 22 23 Notes: This is the TSU compiled version. References are highlighted where they are not yet published. 24 25 26 Table of Contents 27 28 Executive Summary ............................................................................................................................................................ 3 29 3.1 Introduction................................................................................................................................................................. 6 30 3.2 Changes in Surface Climate: Temperature ................................................................................................................. 7 31 3.2.1 Background.................................................................................................................................................... 7 32 3.2.2 Temperature in the Instrumental Record for Land and Oceans.................................................................... 8 33 Question 3.1: How are Temperatures on the Earth changing?.......................................................................................... 15 34 3.3 Changes in Surface Climate: Precipitation, Drought and Surface Hydrology ........................................................ 16 35 3.3.1 Background.................................................................................................................................................. 16 36 3.3.2 Changes in Large-scale Precipitation ......................................................................................................... 17 37 3.3.3 Evaporation ................................................................................................................................................. 21 38 3.3.4 Changes in Soil Moisture, Drought, Runoff and River Discharge .............................................................. 22 39 3.3.5 Consistency and Relationships between Temperature and Precipitation ................................................... 24 40 Question 3.2: How is precipitation changing? .................................................................................................................. 25 41 3.4 Changes in the Free Atmosphere.............................................................................................................................. 26 42 3.4.1 Temperature of the Upper Air: Troposphere and Stratosphere .................................................................. 26 43 3.4.2 Water Vapour............................................................................................................................................... 32 44 3.4.3 Clouds .......................................................................................................................................................... 37 45 3.4.4 Radiation...................................................................................................................................................... 40 46 Box 3.1: The Dimming of the Planet and Apparent Conflicts in Trends of Evaporation and Pan Evaporation............... 43 47 3.5 Changes in Atmospheric Circulation........................................................................................................................ 43 48 3.5.1 Surface or Sea Level Pressure ..................................................................................................................... 44 49 3.5.2 Geopotential Height, Winds and the Jet Stream.......................................................................................... 44 50 3.5.3 Storm Tracks............................................................................................................................................... 45 51 3.5.4 Blocking ....................................................................................................................................................... 46 52 3.5.5 The Stratosphere.......................................................................................................................................... 47 53 Box 3.2: Stratospheric-Tropospheric Relations and Downward Propagation................................................................... 48 54 3.5.6 Winds, Waves and Surface Fluxes ............................................................................................................... 49 55 3.5.7 Summary ...................................................................................................................................................... 50 56 3.6 Patterns of Circulation Variability............................................................................................................................ 50 57 3.6.1 Teleconnections ........................................................................................................................................... 50 58 Box 3.3: Defining the Indices............................................................................................................................................ 51 59 3.6.2 El Niño-Southern Oscillation and Tropical/Extra-tropical Interactions .................................................... 52 60 3.6.3 Decadal Pacific Variability ......................................................................................................................... 54 Do Not Cite or Quote 3-1 Total pages: 120 First-Order Draft Chapter 3 IPCC WG1 Fourth Assessment Report 1 3.6.4 The North Atlantic Oscillation (NAO) and Northern Annular Mode (NAM).............................................. 55 2 3.6.5 The Southern Hemisphere and Southern Annular Mode (SAM).................................................................. 56 3 3.6.6 Other Indices................................................................................................................................................ 57 4 3.6.7 Summary ...................................................................................................................................................... 58 5 3.7 Changes in the Tropics and Subtropics..................................................................................................................... 59 6 3.7.1 Monsoons..................................................................................................................................................... 59 7 3.7.2 The Hadley and Walker Circulations, ITCZ, and Subtropical Highs.......................................................... 62 8 3.8 Changes in Extreme Events ...................................................................................................................................... 64 9 3.8.1 Background.................................................................................................................................................. 64 10 3.8.2 Evidence for Changes in Variability or Extremes ....................................................................................... 65 11 Box 3.4: Tropical Cyclones and Climate Change ............................................................................................................ 68 12 3.8.3 Evidence for Changes in Tropical and Extratropical Storms and Extreme Events..................................... 69 13 Box 3.5: Specific Extreme Events..................................................................................................................................... 74 14 3.8.4 Summary ...................................................................................................................................................... 76 15 Question 3.3: Has there Been a Change in Extreme Events like Heat Waves, Floods, Droughts, and Hurricanes? ........ 77 16 3.9 Synthesis: Consistency Across Observations ........................................................................................................... 78 17 References ......................................................................................................................................................................... 82 18 Appendix 3.A: Techniques, Error