Indicator Trends for Canadian Climate Changes during the Last 60 to 140 Years

Transcription

1 Indicator Trends for Canadian Climate Changes during the Last 60 to 140 Years Presented to CPANS, Edmonton Luncheon Forum by Kurt Hansen, P. Eng. President, Green Inc., Calgary, Alberta 6 March 2015

2 Acknowledgements My sincere thanks to Dr. Stanley Hall and Klym Bolechowsky for suggestions and assistance This presentation is dedicated to Marie & Edith both diligent weather-observing Danish farmers (from 1890 to 1974), who inspired me about weather conditions 2

3 Overview Stations & periods of records (POR) Climate change (CC) indicators Temperature related indicator findings Precipitation related indicator findings Conclusions from findings 3

4 Weather Station Locations 4

5 Periods of Temperature Records (POR) (enginering daily data) 5

6 Climate Change Indicators Temperature related trends: Extreme temperatures (indicators for deep freezes & heat waves) Mean annual & seasonal temperatures Days between absolute min and max of cumulative degree days, with carry-over into next year (relative to 0 C) Precipitation related trends: Average annual precipitation (total & snow) Extreme drought & drench (D&D) rain to temperature ratio indicators 6

7 Indicator Trend Metrics Years for increasing (+) or decreasing (-) trend change of: 1 C (and the related variable: Cdays relative to 0 C) 1 day duration, between absolute plus to minus seasonal temperature changes (cumulative min and max Cday values) 10 mm rain (and equivalent 10 cm snow) APR-SEP growing period: rain to temperature ratio (increment unit of mm Cday 10% average summer pan evaporation) 7

8 TRENDS IN TEMPERATURE RELATED INDICATORS EXAMPLES & SUMMARIES 8

9 Approach: Extreme Min Temperature Indicator 9

10 Example: Extreme Annual Temperatures (engineering daily data) 10

11 Summary: Extreme Annual Temperatures (engineering daily data) 11

12 Approach: Indicators for Seasonal Mean Temperatures (Spring & Summer (SS) and Autumn & Winter (AW) periods) 12

13 Calgary IAP Example: Mean SS, Annual & AW Temperatures (linear and 3rd power polynomial trends) 13

14 Other Examples: Mean SS, Annual & AW Temperatures (3rd power polynomial trends) 14

15 Summary: Warming Trends (ER & RR) (3rd power polynomial trends) 15

16 Summary: Recent versus Early Warming Trends (3rd power polynomial trends) 16

17 Summary: Recent versus Early SS & AW Period Trends 17

18 Example: Engineering Daily versus Homogenized Monthly Data (mean annual temperature trends) 18

19 Summary: Recent versus Early Warming Trends (Original (ORG) vs homogenized (HOM) data) 19

20 TRENDS IN PRECIPITATION RELATED INDICATORS EXAMPLES & SUMMARIES 20

21 Example: Annual Total Precipitation & Snow 21

22 Summary: Annual Total Precipitation & Snow (homogenized data) 22

23 Approach: APR-SEP Precipitation Event Indicators (15 to 45 annual events event percentiles for each year) 23

24 Example: Consecutive Dry Days 24

25 Summary: Consecutive Dry Days (90th Percentile) 25

26 Example: Rain to Temperature (D&D) Event Ratio Trends (original (percentiles) & homogenized (average) data) 26

27 Summary: Rain to Temperature (D&D) Event Ratio Trends (years for 0.025mm/Cday change) th Percentiles Agassiz 75th Percentiles St. John's years Charlottetown mm/cday mm/cday Swift Current 1903 Churchill White Sand Dam Ft. Smith Ft. Good Hope years 1873 Charlottetown Swift Current Ft. Smith St. -6 years years th Percentiles th Percentiles Agassiz White Sand +51 years mm/cday mm/cday Indian Bay Welland years Calgary Indian +13 years years Ft. Good Hope

28 Conclusions 1. Past trend has been longer, warmer spring & summer periods versus shorter, warmer autumn and winter periods 2. Moderate cooling periods of years duration occurred from 1913 to Otherwise more than moderate warming periods 3. Recent decades of annual rates of warming range from 10 to 65 years for a 1 Celcius increase in annual mean temperature (versus 18 to 92 years for early decades of the records) 4. Overall trend at two-thirds of the stations is toward more Total Annual Precipitation (7 to 26 years for a 10 mm increase) 6. Recent trend in the spring & summer rain precipitation to temperature event ratio is toward drought at two-thirds of the stations (versus 50/50 trend toward drench ) - however at slower trend decreases than during earlier record periods 28

29 Thank you for your attention Questions are much welcomed 29