Water in the Columbia, Effects of Climate Change and Glacial Recession

Size: px

Start display at page:

Download "Water in the Columbia, Effects of Climate Change and Glacial Recession"

Junior Murphy
5 years ago
Views:

Water in the Columbia, Effects of Climate Change and Glacial Recession John Pomeroy, Centre for Hydrology University of Saskatchewan, Saskatoon @Coldwater Centre,

1 Water in the Columbia, Effects of Climate Change and Glacial Recession John Pomeroy, Centre for Hydrology University of Saskatchewan, Centre, Biogeoscience Institute, University of Calgary with contributions from Mike Demuth, Dan Moore, Masaki Hayashi, Al Pietroniro, Laura Comeau,, Chris Hopkinson, Katrina Bennett

2 Columbia Basin Snow and Ice southernmost, interior summer snow water reserves Snow depth in January Snow depth in June

3 Canadian Rockies are the Hydrological Apex of North America

4 Columbia River Basin Annual Precipitation Hicks

Hara O (5% glacier cover on Opabin Plateau) Flow to

5 Sources of Mountain Streamflow Streamflow contribution related to glacier area Study of Lake O Hara O (5% glacier cover on Opabin Plateau) Flow to Lake O HaraO 60% snowmelt 35% rainfall 5% glacier melt Hayashi

6 Water Input to the Opabin Watershed snow melt glacier melt 1.5 flux (m 3 /s) /1 5/21 6/10 6/30 7/20 8/9 8/29 9/18 10/ Hayashi

7 Water Input to the Opabin Watershed snow melt glacier melt rain 1.5 flux (m 3 /s) /1 5/21 6/10 6/30 7/20 8/9 8/29 9/18 10/ Hayashi

8 Hydrograph of a Glacierised Stream, Rockies Young

Glacier Ice Wastage and Melt contribution to streamflow Peyto Glacier basin streamflow Aug 08 Wastage

increasing volumes of wastage in the short term Long term wastage contributions will decrease past a

contribute to the total annual streamflow volume Snow is accumulated into the glacier system instead of

erature The equivalent runoff volume contributes to streamflow as ice melt in July to September The

9 Glacier Ice Wastage and Melt contribution to streamflow Peyto Glacier basin streamflow Aug 08 Wastage increases the total annual streamflow volume Glaciers receding at an increasing rate contribute increasing volumes of wastage in the short term Long term wastage contributions will decrease past a threshold where the declining glacier area limits the volume of wastage produced Melt does not contribute to the total annual streamflow volume Snow is accumulated into the glacier system instead of melting and a contributing to streamflow in May and June due to the cooler ice surface temperature erature The equivalent runoff volume contributes to streamflow as ice melt in July to September The glacier effectively delays runoff to the late summer months of otherwise low flow, and contributes to seasonal streamflow in terms of Melt.

10 Contribution of the Melt of Snow and Ice on a Glacier to Late Summer Streamflow Comeau, 2008

11 Ice Wastage Contribution to Streamflow as a Function of Glaciation of a River Basin Comeau, 2008

12 Current Glacier Melt Contribution to River Discharge Fall % Annual % Fall Annual % % Mike Demuth, Natural Resources Canada

Regional climate change predictions 2080-2089 2089 relative to 1980-1999 1999

13 Regional climate change predictions relative to Annual Winter - DJF Summer - JJA IPCC 2007 Warmer and Wetter generally; Drier in summer!

14 Rainfall versus Snowfall, Kananaskis Valley Temperature Change Warmer winters = less snowfall Warmer winters = more rainfall Harder & Pomeroy

15 Streamflow Trends Bennett, PCIC

Glaciers in the Rocky Mountains Glacial Decline:

19th Century 1975-1998 1998 total glacier loss: NSRB

continue into the future Impacts: Reduced river

16 Glaciers in the Rocky Mountains Glacial Decline: Glaciers receding in the Rocky Mountains since the 19th Century total glacier loss: NSRB 23% ( km²) SSRB 37% ( km²) Projected to continue into the future Impacts: Reduced river flows in late summer months Increased streamflow variability 1896 W. Wilcox 2008 Hydroelectric power plants Ecology Agriculture Domestic Peyto Glacier Lateral Moraines

17 Glacier Retreat Rocky Mountains Mapped from NASA LANDSAT satellite Glaciers are fed by alpine snow 37% loss of glaciated area of South Sask River Basin % loss of glaciated area of North Sask River Basin Demuth & Pietroniro

18 Demuth Columbia Icefield

19 Yesterday Today Tomorrow Volume per time Moore et al

20 Historical variations of Illecillewaet Glacier

21 Sensitivity of August streamflow to August air temperature as influenced by glacier cover Increase in streamflow for an increase in air temperature coefficient b glacier cover (%) Moore

22 Streamflow response to climate warming: hypothesis Q (% of pre-shift mean) Onset of warming and shift to negative mass balance 0 Time Moore

23 25 Mistaya River Monthly Flow(CMS) /1/80 12/1/83 4/1/87 8/1/90 Time (month) 40 Siffleur River Monthly Flow(CMS) /1/80 12/1/83 4/1/87 8/1/90 Time (month) 100 Ram River Monthly Flow(CMS) /1/80 12/1/83 4/1/87 8/1/90 Time (month) 1998 extent 1975 Extent None Pietroniro and Demuth

24 Meteorological Stations

25 Hydrological Observation

26 New Observations Needed Station density is too low. To meet World Meteorological Organisation standards for mountain regions we need 4.5 fold increase in streamflow (hydrometric) stations 22.5 fold increase in precipitation stations 0.04 Station Density p er km Weather Station Hydrometric Station Snow Station < Elevation

27 Observations Clustered in Small Basins Improve Understanding

28 Prediction 2003 Q [m 3 /s] Obs Aggregated Distributed /17/03 4/26/03 5/05/03 5/14/03 5/23/03 6/01/03 Time [days]

29 Modelling in Columbia Models should be physically based Temperature index unsuited for climate change or land use change snowmelt calculations Radiation can estimated accurately from temperature range and output from climate models Models should have realistic snow and glacier components Models must explicitly recognize the influence of topography, slope and aspect on watershed response

30 CRHM Coupled Blowing Snow and Snowmelt Modelling for Mountains Meteorological Inputs T, RH, U, P, K Latitude, elevation, slope, aspect, vegetation, fetch, area Radiation, windflow and temperature recalculations Spatially Distributed K, L, u*, T, q, snowfall, rain Albedo Decay Blowing Snow Model Sublimation, Transport Snobal Snowmelt Model ΔSWE, Melt, Sublimation

31 Winter Warming Scenario Impact on Mid-Alpine Ridge Snow Regime 200 reference simulation SWE (mm) C + 2 C + 3 C + 4 C /11/06 30/12/06 29/01/07 28/02/07 30/03/07 29/04/07 29/05/07

GCM scenario results hydrological model 2039 2070 cumulative flows of South Saskatchewan River Red Deer at Bindloss -13%

32 GCM scenario results hydrological model cumulative flows of South Saskatchewan River Red Deer at Bindloss -13% (-32% to 13%) South Sask a Diefenbaker -8.5% (-22% to 8%) Bow River at mouth -10% (-19% to 1%) Oldman at mouth -4% (-13% to 8%)

33 Columbia Icefield Research Initiative Jasper Columbia Icefields Visitor Centre Lake Louise

34 Conclusions Glacier contribution to streamflow depends on climate & glacierised area this contribution is incompletely quantified in the Columbia basin. Further deglaciation likely to result in lower and more variable late summer streamflow Change in hydrology due to climate change and deglaciation depends on what land cover replaces glacier cover (tundra, forest, rock) Current hydrological modelling has simple or no representation of glaciers, snow and alpine energy balance adds considerable uncertainty to estimating the future water resources of the region.

Calgary s Water in a Changing Climate? Look upstream

Calgary s Water in a Changing Climate? Look upstream Michael N. Demuth, Alain Pietroniro, Steve Grasby and Chris Spence with John Pomeroy, Bob Sandford, Masaki Hyashi and Shawn Marshall Outline Calgary