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Regional Climate Change Detection

Regional Climate Change Detection. What is a climate? How does one define a climate in terms of measured variables?

aiko-mathews
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Regional Climate Change Detection

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  1. Regional Climate Change Detection • What is a climate? • How does one define a climate in terms of measured variables? • After defining it, how does one measure actual change in a statically defensible manner. Most of local climate change is simply assumed to be occurring because global change is occurring

  2. Anecdotal Evidence Often Used • More frequent extreme-heat days • A longer growing season • An increase in heavy rainfall events • Earlier breakup of winter ice on lakes and rivers • Earlier spring snowmelt resulting in earlier high spring river flows • Less precipitation falling as snow and more as rain • Reduced snowpack and increased snow density

  3. Use an Indexing Method • Climate is largely a monthly/seasonal phenomena – not annual • Take a weather site and say it has 100 years of data for all 12 months and pick a variable like max temperature. Use all 100 months of January to compose the average max. • For each month then in each year, compute the Z-score for that month/year • Z-Score= (x - µ) / 

  4. Now Generate a Composite Index • NEIyr= (Zmxyr+ Zmnyr+ Zrnyr + Zswyr) / 4 • Can then weight each of the 4Z’s • The result is a wave form some given site for one of the Z parameters

  5. This form of Indexing • Is identical to the approach used for the Stock Market; what matters is the behavior over time of the relative amplitude of the Index.

  6. Weighting the Indicators: • WMAX0.250.250.250.25 (equal) • WGD10.4 0.4 0.1 0.1 (emphasize temp) • WGD2 0.2 0.1 0.6 0.7 (emphasize rain) • Just try all kinds of combinations: Dick with the data! • There is no “right” way to do this just a consistent way.

  7. Sum up all the good stations

  8. Deconvolve the parameters

  9. Define the Index Seasonally: Each Arrow Is separated by Exactly 40 years

  10. Experiment with Weights:

  11. The Pacific Northwest Index

  12. Predict the Future

  13. Cool Wet To Return in 2000

  14. The RPNI (Pacific Northwest)

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