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 greeninc@telus.net 6 March 2015
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
Overview Stations & periods of records (POR) Climate change (CC) indicators Temperature related indicator findings Precipitation related indicator findings Conclusions from findings 3
Weather Station Locations 4
Periods of Temperature Records (POR) (enginering daily data) 5
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
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 0.025 mm Cday 10% average summer pan evaporation) 7
TRENDS IN TEMPERATURE RELATED INDICATORS EXAMPLES & SUMMARIES 8
Approach: Extreme Min Temperature Indicator 9
Example: Extreme Annual Temperatures (engineering daily data) 10
Summary: Extreme Annual Temperatures (engineering daily data) 11
Approach: Indicators for Seasonal Mean Temperatures (Spring & Summer (SS) and Autumn & Winter (AW) periods) 12
Calgary IAP Example: Mean SS, Annual & AW Temperatures (linear and 3rd power polynomial trends) 13
Other Examples: Mean SS, Annual & AW Temperatures (3rd power polynomial trends) 14
Summary: Warming Trends (ER & RR) (3rd power polynomial trends) 15
Summary: Recent versus Early Warming Trends (3rd power polynomial trends) 16
Summary: Recent versus Early SS & AW Period Trends 17
Example: Engineering Daily versus Homogenized Monthly Data (mean annual temperature trends) 18
Summary: Recent versus Early Warming Trends (Original (ORG) vs homogenized (HOM) data) 19
TRENDS IN PRECIPITATION RELATED INDICATORS EXAMPLES & SUMMARIES 20
Example: Annual Total Precipitation & Snow 21
Summary: Annual Total Precipitation & Snow (homogenized data) 22
Approach: APR-SEP Precipitation Event Indicators (15 to 45 annual events event percentiles for each year) 23
Example: Consecutive Dry Days 24
Summary: Consecutive Dry Days (90th Percentile) 25
Example: Rain to Temperature (D&D) Event Ratio Trends (original (percentiles) & homogenized (average) data) 26
Summary: Rain to Temperature (D&D) Event Ratio Trends (years for 0.025mm/Cday change) 0.095 0.660 25th Percentiles Agassiz 75th Percentiles 0.610 0.085 0.560 0.075 St. John's 0.460 Churchill @ -36 years Charlottetown mm/cday mm/cday 0.065 0.055 0.045 Swift Current 1903 Churchill 0.360 1933 0.065 White Sand Dam Ft. Smith 0.210 Ft. Good Hope 0.160 Atlin @ -406 years 1873 Charlottetown 0.260 0.025 0.015 0.410 0.310 Swift Current Ft. Smith 0.035 St. John's @ -6 years 0.510 1963 Atlin @ -36 years 0.110 1873 1993 1903 1933 0.510 25th Percentiles 1993 75th Percentiles Agassiz White Sand Dam @ +51 years 1963 0.460 0.055 0.410 0.045 mm/cday mm/cday Indian Bay Welland 0.360 0.310 0.260 0.035 Welland @ +28 years Calgary Indian Bay @ +13 years 0.210 Calgary @ +239 years 0.025 1873 1903 1933 Ft. Good Hope 0.160 1963 1993 1873 1903 1933 1963 1993 27
Conclusions 1. Past trend has been longer, warmer spring & summer periods versus shorter, warmer autumn and winter periods 2. Moderate cooling periods of 20-50 years duration occurred from 1913 to 1978. 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
Thank you for your attention Questions are much welcomed 29