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Task 1 – Projection Selection Considerations

Task 1 – Projection Selection Considerations Task 3.1 – Adjusting Inflow Data for Reservoir Simulation Models. Levi Brekke (Reclamation, Denver, CO). 9 June 2009, Portland, OR. Task 1 – Projection Selection Considerations. Our Focus: Hydrology-related Impacts. Task 1.

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Task 1 – Projection Selection Considerations

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  1. Task 1 – Projection Selection Considerations Task 3.1 – Adjusting Inflow Data for Reservoir Simulation Models Levi Brekke (Reclamation, Denver, CO) 9 June 2009, Portland, OR

  2. Task 1 – Projection Selection Considerations

  3. Our Focus: Hydrology-related Impacts Task 1 1) Survey Global Climate Projections over the study region 3) Define water suppliesandhydrology-related inputs in terms of climate info from 2.b; characterize uncertainties Hydrologic Response 2.a) Decide how/whether to cull the information. 4) Assess operations and dependent resource responses; characterize uncertainties 2.b) Decide how retained information will be used.

  4. Information from CIG • Hybrid • Paired sequences of climate and hydrology data • Sequence #1: Observed Historical • Sequence #2: “Climate Changed” • Specific to a given projection and a given future period

  5. Information from CIG • Hybrid • Observed Historical Climate and Hydrology • Climate • Defined by 1916-2006 (91 years) daily observed weather • Hydrology • VIC-simulation forced by daily observed weather • Produces 91 years of daily gridded water balance • Post-simulation routing produces 91-years of routed natural runoff to locations of interest (e.g., inflow locations to reservoir simulation models) • Further post-analysis converts natural runoff to modified flows • Reflects observed statistics and sequence

  6. Information from CIG • Hybrid • Climate Changed Hydrology • Climate • 91 years of daily weather reflecting statistics of a given projection and future period in that projection (Alan’s talk) • 2010-2039 (~2025) • 2030-2059 (~2040) • Hydrology • Similar to Observed Historical (91 years, daily), but reflects different climate • Repeated for 20 climate projections x 2 future periods  40 candidate Hybrid scenarios from CIG

  7. Information from CIG • Hybrid scenario selections • How many of CIG’s Hybrid scenarios do we want to use in this study? • Guiding philosophy: • Reflect the “spread” of climate change information from CIG • Reflect the central tendency of this information also (e.g., centrally estimated “climate change” increment) • Potential scheme … • Reclamation 2009, San Joaquin River Restoration Program (SJRRP) PEIS/R

  8. Projection Selection Factors:SJRRP Choices • Climate Periods: 1971-2000, 2011-2040 (accomplishments horizon is through 2030) • Climate Change Metrics: Period Mean-Annual Tair & P (CVP performance trends with annual P) • Climate Change Location: “Above Millerton” (more interest on water supply local to SJRRP) • Change Thresholds of Interest: 10 to 90 %-tile changes like OCAP, plus choice near medians

  9. Implementation of SJRRP Factors:Step 1) Survey projections “Above Millerton” 1a. From website, download monthly Tair & P time series. 1b. Compute historical and future period “climate metrics” for every projection. 1c. Compute historical-to-future period changes in “climate metric” for every projection.

  10. Implementation of SJRRP Factors:Step 2) Construct scatterplot of projections’ mean-annual changes in temperature and precipitation

  11. Implementation of SJRRP Factors:Step 3) Select 4 bracketing projections, plus one central from the scatterplot produced in Step 2) • (drier, more warm) ncar_ccsm3_0, run 6, B1 • P change: -13.6% T change: +2.8F • (drier, less warm) mri_cgcm2_3_2a, run 4, A1b • P change: -9.8% T change: +0.9F • (wetter, less warm) mri_cgcm2_3_2a, run 1, B1 • P change: +16.3% T change: +0.9F • (wetter, more warm) inmcm3_0, run 1, A2 • P change: +9.0% T change: +2.6F • (“central”) mpi_echam5, run 1, A1b • P change: -0.3% T change: +1.8F

  12. Implementation of SJRRP Factors:Step 3) Select 4 bracketing projections, plus one central from the scatterplot produced in Step 2)

  13. Implementation of SJRRP Factors:Step 4) Check how 4 bracketing projections at “Above Millerton” encapsulate spread at other locations • Above Millerton: Southern Central Valley • Above Folsom: Mid-Central Valley • Above Shasta: Northern Central Valley

  14. Above Millerton (southern valley) Implementation of SJRRP Factors:Step 4) Check how 4 bracketing projections at “Above Millerton” encapsulate spread at other locations

  15. Implementation of SJRRP Factors:Step 4) Check how 4 bracketing projections at “Above Millerton” encapsulate spread at other locations Above Folsom (mid-valley)

  16. Implementation of SJRRP Factors:Step 4) Check how 4 bracketing projections at “Above Millerton” encapsulate spread at other locations Above Shasta (northern valley) Main Point: Projection spread varies by location. So would selections for bracketing and “central” projections. We anticipate this would be the case in our study also…

  17. Information from CIG • Hybrid • Preliminary Selection Plans • One “Base” Sequence: Observed Historical • Ten “Climate Changed” Sequences • Five for ~2025 climates (4 bracketing, 1 central) • Five for ~2040 climates (4 bracketing, 1 central)

  18. Information from CIG • Transient • single sequences of climate and hydrology data • Sequence spans “Simulated Historical” to “Projected Future” • “Simulated Historical” • Bias-corrected during 1950-1999 to be statistically consistent with observed-historical • Does not have the same sequencing characteristics

  19. Information from CIG • Transient • Climate Changed Hydrology • Climate • 1950-2099 (150 years) of daily weather • reflects evolving monthly statistics of a given projection • reflects relatively daily variability from observed historical but • with potentially more extreme scaling/shifting on a month-specific basis compared to Hybrid (Alan’s talk) • With more discontinuities (all month boundaries) compared to Hybrid • Hydrology • 1950-2099, daily • Repeated for 20 climate projections  20 candidate Transient projections from CIG

  20. Information from CIG • Transient • Preliminary Selection Plans • All transient projections that underly selected Hybrid scenarios • Five for ~2025 climates (4 bracketing, 1 central)  five transient projections • Five for ~2040 climates (4 bracketing, 1 central)  five transient projections • Check for overlap among the five for each period • Total selection will range from 5 to 10.

  21. Task 3.1 – Adjusting (or Preparing) Inflows for Reservoir Simulation

  22. Our Focus: Hydrology-related Impacts Task 3.1 1) Survey Global Climate Projections over the study region 3) Define water suppliesandhydrology-related inputs in terms of climate info from 2.b; characterize uncertainties Hydrologic Response 2.a) Decide how/whether to cull the information. 4) Assess operations and dependent resource responses; characterize uncertainties 2.b) Decide how retained information will be used.

  23. Information from CIG  Task 3 • Hybrid • Preparing Inflow Data for Reservoir Simulation • Model time-steps and traditional periods vary: • BPA HydSim: 14-period, WY 1929-1999 • USACE AutoReg/SSARR: daily, WY 1929-1999 • USACE HEC/ResSim: daily, WY 1929-1999 • USACE HYSSR: 14-period, WY 1929-1999 • Reclamation ModSim-Deschutes: monthly, wy1929-1999 • Reclamation ModSim-Snake: monthly, wy1928-2001 • Reclamation ModSim-Yakima: monthly, wy1929-1999

  24. Information from CIG  Task 3 • Hybrid • Preparing Inflow Data for Reservoir Simulation • Scenario Inflows need to: • reflect decision on simulation period (max: 91 years) • reflect each model’s inflow definitions • Considerations for Climate Change Hydrology: • reflect same level of basin depletion in Observed Historical Hydrology and in Climate Change Hydrology • reflect natural lake effects on runoff routing • CIG has developed data, but Task 3.1 scope includes budget for possible revisions if necessary (relative to Considerations)

  25. Information from CIG  Task 3 • Transient • Preparing Inflow Data for Reservoir Simulation • Scenario Inflows need to: • reflect transient projection period = 150 years (1950-2099) • 1950-2008 is not to be confused with observed historical • 1950-1999 is ~statistically consistent with observed • historical sequencing aspects will differ, for each projection • reflect each model’s inflow definitions • Considerations: • basin depletion representation – see Hybrid • natural lake effects – see Hybrid • CIG has developed preliminary inflows data, but Task 3.1 is scoped for potential revisions (relative to Considerations)

  26. Extras – Texas Study(another Hybrid Example)

  27. Texas Study - Hybrid Example • Report • Prepard by CH2M-Hill • http://www.lcra.org/lswp/about/study/climatechange.html • Section 7.5 describes application of Hybrid Methodology

  28. Texas Study - Hybrid Example 1. 50-year Monthly Observed Distributions for a given grid cell…

  29. Texas Study - Hybrid Example 2. 31-year Monthly Simulated Distributions from a given projection for the same grid cell…

  30. Texas Study - Hybrid Example 3. Percentile-specific adjustments (sim - obs)

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