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Precipitation Intensity

Precipitation Intensity. Climate Impacts Group & Department of Atmospheric Sciences University of Washington. Eric Salathé. Climate Change: North America. Winter. Summer. Annual. Climate Change: Pacific Northwest Precipitation.

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Precipitation Intensity

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  1. Precipitation Intensity Climate Impacts Group&Department of Atmospheric SciencesUniversity of Washington Eric Salathé

  2. Climate Change: North America Winter Summer Annual

  3. Climate Change: Pacific Northwest Precipitation Change in U.S. PNW precipitation by monthfrom 1990s to futuresimulated by 20 climate models Precipitation Change (%)

  4. Changes in Pacific Storm Track • Consensus of current Global Climate Models: • Intensification of Mid-latitude storms • Less frequent storms • Northward shift in storm track

  5. Shift in Pacific Storm Track J Yin, Geophys Res Lett, 2005 Temperature Change 1980-2000 to 2080-2100 Change in Storm Growth S Pole EQ N Pole S Pole EQ N Pole

  6. Shift in Pacific Storm Track 1950-2000 to 2050-2100 Nov-Dec-Jan 20th Century Model Composite Observed (NCEP-NCAR Reanalysis) 21st Century Model Composite Salathé, Geophys Res Lett, 2006

  7. Shift in Aleutian Low 1950-2000 to 2050-2100 Nov-Dec-Jan Observed 20th Century Model Composite Salathé, Geophys Res Lett, 2006

  8. Movement of Jetstream 1950s

  9. Movement of Jetstream 1960s

  10. Movement of Jetstream 1970s

  11. Movement of Jetstream 1980s

  12. Movement of Jetstream 1990s

  13. Movement of Jetstream 1950s

  14. Are extreme rain events becoming more frequent? Valérie Dulière, Philip Mote, Eric Salathé, Josiah Mault and Marketa McGuire Elsner (Climate Impacts Group, University of Washington) 2008 Pacific Northwest Weather Workshop Source : THE OREGONIAN/Bruce Ely

  15. The Chehalis River flooding Source : THE OREGONIAN/Bruce Ely

  16. The Centralia station

  17. The Centralia station Distribution function of daily precipitations from 1948 to 2006 5 cm 10 cm

  18. The Centralia station Distribution function of daily precipitations from 1948 to 2006 (Zoom) 5 cm 10 cm

  19. The Centralia station Distribution function of daily precipitations from 1948 to 2006 (Zoom) 1994, 1986 1951, 1981 1986 2006 1990 1990 1986 1996 2001 5 cm 10 cm

  20. The Centralia station Distribution function of daily precipitations from 1948 to 2006 (Zoom) Since 1948, 80% of the 20 greatest extreme daily rain events occurred after 1985! 1994, 1986 1951, 1981 1986 2006 1990 1990 1986 1996 2001 5 cm 10 cm

  21. 3.3 in 2.5 yr The Centralia station Return period of annual maximum daily precipitation --1948-1976 --1977-2006

  22. The Past 50 Years Source : THE OREGONIAN/Bruce Ely

  23. The Cooperative Observer Program network

  24. The Centralia station Return period of annual maximum daily precipitation 10-year Return } Percent Change --1948-1976 --1977-2006

  25. Percentages of change in the annual maximum daily precipitation with a 10 years return period for each station 1 2 3 4 5 6 7 8 9 10

  26. 1 2 7 3 4 5 6 10 8 9

  27. What Do Climate Models Project for the Future? Source : THE OREGONIAN/Bruce Ely

  28. Projected Future Changes from Climate Models (2046-2065 versus 1981-2000)

  29. Projected Future Changes from Climate Models (2046-2065 versus 1981-2000) SRES A1B SRES B1 IPSL ECHAM5 CCSM3 Percentages of change in the annual maximum daily precipitation with a 10 years return period for each grid cell between 1981-2000 and 2046-2065.

  30. Projected Future Changes from Climate Models (2046-2065 versus 1981-2000) SRES A1B SRES B1 IPSL +18.8% +11.8% ECHAM5 CCSM3 Percentages of change in the annual maximum daily precipitation with a 10 years return period for each grid cell between 1981-2000 and 2046-2065.

  31. Projected Future Changes from Climate Models (2046-2065 versus 1981-2000) SRES A1B SRES B1 IPSL +18.8% +11.8% ECHAM5 +11.4% +10.6% CCSM3 Percentages of change in the annual maximum daily precipitation with a 10 years return period for each grid cell between 1981-2000 and 2046-2065.

  32. Projected Future Changes from Climate Models (2046-2065 versus 1981-2000) SRES A1B SRES B1 IPSL +18.8% +11.8% ECHAM5 +11.4% +10.6% CCSM3 +12.2% +10.8% Percentages of change in the annual maximum daily precipitation with a 10 years return period for each grid cell between 1981-2000 and 2046-2065.

  33. Projected Future Changes from Climate Models (2046-2065 versus 1981-2000) Number of days per year with P > 0.4 inches Number of days per year

  34. Number of days per year with P > 0.4 inches P > 1.6 inches Number of days per year

  35. Projected Future Changes from Climate Models (2046-2065 versus 1981-2000) Number of days per year with P > 0.4 inches P > 1.6 inches P > 2.8 inches Number of days per year

  36. GOING TO THE EXTREMES • GOING TO THE EXTREMESAN INTERCOMPARISON OF MODEL-SIMULATED HISTORICAL AND FUTURE CHANGES IN EXTREME EVENTS CLAUDIA TEBALDI , KATHARINE HAYHOE, JULIE M. ARBLASTER and GERALD A. MEEHL, Climatic Change (2006) 79: 185-211 • 9 Global Model Simulations for IPCC • 1. Number of days with precipitation greater than 10 mm (precip > 10). • 2. Maximum number of consecutive dry days (dry days). • 3. Maximum 5-day precipitation total (5 day precip). • 4. Simple daily intensity index, defined as the annual total precipitation divided by the number of wet days (precip intensity). • 5. Fraction of total precipitation due to events exceeding the 95th percentile of the climatological distribution for wet day amounts (precip > 95th).

  37. Going to Extremes

  38. Going to Extremes

  39. Mesoscale Effects • Global models do not resolve fine-scale processes such as topographic precipitation • Downscaling methods are used to account for regional effects • Statistical downscaling uses observed relationship between large-scale and fine-scale patterns to extrapolate to climate model results • Regional climate model simulates fine-scale physical processes

  40. Change in Orographic Enhancement 1990-2000 to 2045-2055 Sept-Oct-Nov Downscaling without wind effect Downscaling with wind effect Salathé, Geophys Res Lett, 2006

  41. Mesoscale Climate Model • Based on Regional Weather Model (MM5, WRF) • Nested grids 135-45-15 km • Advanced land-surface model (NOAH) with interactive deep soil temperature • Global Climate Model used as Input (boundary conditions)

  42. Autumn Precipitation Changes Change in Orographic Enhancement Change in Autumn precipitation rate from 1990s to 2050sas simulated in regional climate model WindsShift toOnshore Rain increases along mountain ridge mm per day

  43. MM5 vs Statistical Downscaling Statistical Downscaling MM5 P only P & Wind Change in November Precip (mm/day) 1990s to 2050s

  44. Conclusions : • This is the beginning of our work. • According to the observations from the COOP network, extreme rain events have globally increased in frequency and intensity between 1948-1976 and 1977-2006 over the Washington state. • According to global climate models (IPSL, ECHAM5 and CCSM3), extreme rain events will in average be more intense and more frequent in 2046-2065 than now, over the PNW region. Coming next : Analysis of output from regional climate models. Source : http://www.earthcam.com/

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