1. Research on snow/hydroclimate processes and trends, integration with CanSISE Stephen Déry Marco Hernández-Henríquez Do-Hyuk “DK” Kang 1 CanSISE Workshop 1 – Oct. 31 st, 2013

2. POLAR AMPLIFICATION AND ELEVATION DEPENDENCE OF SNOW COVER EXTENT TRENDS IN THE NORTHERN HEMISPHERE, 1972-2012 – A CONTRIBUTION TO CanSISE PROJECT C3.1 Marco A. Hernández-Henríquez and Stephen Déry

3. BACKGROUNDBACKGROUND Recent years have exhibited marked declines in snow cover extent (SCE) in the Northern Hemisphere, especially with the springtime offset advancing (Brown et al. 2010; Derksen and Brown 2012 ). Recent years have exhibited marked declines in snow cover extent (SCE) in the Northern Hemisphere, especially with the springtime offset advancing (Brown et al. 2010; Derksen and Brown 2012 ). In northern latitudes, the snow-albedo feedback is highest in the spring and amplifies these decreasing trends in SCE (Déry and Brown 2007). In northern latitudes, the snow-albedo feedback is highest in the spring and amplifies these decreasing trends in SCE (Déry and Brown 2007). Increasing temperatures and precipitation could alter the declining trends in SCE depending on latitude and elevation (Brown and Mote 2009). Increasing temperatures and precipitation could alter the declining trends in SCE depending on latitude and elevation (Brown and Mote 2009). 3

4. RESEARCH GOALS Update the 1972-2006 trends in Northern Hemisphere SCE presented in Déry and Brown (2007) to include data from 2007 to 2012 from the NOAA weekly SCE dataset maintained at Rutgers University. Update the 1972-2006 trends in Northern Hemisphere SCE presented in Déry and Brown (2007) to include data from 2007 to 2012 from the NOAA weekly SCE dataset maintained at Rutgers University. Examine latitudinal and elevational variations in the presence of snow Examine latitudinal and elevational variations in the presence of snow Observe trends in snow coverage with latitude and elevation. Observe trends in snow coverage with latitude and elevation. Determine if there is latitudinal and elevational dependence of snow cover over time and potential impacts to the surface radiation budget. Determine if there is latitudinal and elevational dependence of snow cover over time and potential impacts to the surface radiation budget. 4

5. METHODSMETHODS A.Linear regressions are used to investigate trends in snow coverage (significant when p < 0.05) by 1 o latitudinal bands and at continental scales. i.Computed trends in the fraction of time that a latitude band is snow-covered over the study period. ii.Plotted trends in the total area of snow cover as a function of latitude. iii.Assess snow coverage trends by climatological snow cover fraction. 5

6. METHODSMETHODS B. Linear regressions are used to investigate trends in snow coverage (significant when p < 0.05) by elevation bands of 100 m. i.Computed trends in the fraction of time that each elevation band is snow-covered over the study period. C.Assessed absolute, standardized and solar insolation- weighted trends (significant when p < 0.05). The latter are computed by multiplying absolute SCE values by the ratio of the weekly average and annual maximum incoming solar radiation at 60 o N. 6

7. 7 Large dots indicate significant trends (black = p < 0.05 and red = p < 0.0001) Large dots indicate significant trends (black = p < 0.05 and red = p < 0.0001)

8. 8

9. 9

10. 10 Large dots indicate significant trends (black = p < 0.05 and red = p < 0.0001) Large dots indicate significant trends (black = p < 0.05 and red = p < 0.0001)

11. 11 Dots indicate significant (p < 0.05) trends

12. 12 Dots indicate significant (p < 0.05) trends

13. 13

14. CONCLUSIONSCONCLUSIONS The retreat of Northern Hemisphere snow cover has accelerated in recent years with the strongest trends at high latitudes and with most frequent snow coverage. The greatest potential impacts to the surface radiation budget are at high latitudes (60-70 o N) during spring. The greatest potential impacts to the surface radiation budget are at high latitudes (60-70 o N) during spring. These results provide further evidence of a polar amplification of snow cover extent trends, with the snow- albedo feedback enhancing the trends. These results provide further evidence of a polar amplification of snow cover extent trends, with the snow- albedo feedback enhancing the trends. 14

15. The changing contribution of snow to the hydrology of the Fraser River Basin – A contribution to CanSISE Project B3 Do-Hyuk ‘DK’ Kang 1, Xiaogang Shi 2, Huilin Gao 3 and Stephen Déry 1 1 Environmental Science and Engineering Program University of Northern British Columbia 2 National Hydrology Research Centre Environment Canada 3 Zachry Department of Civil and Environmental Engineering Texas A & M University October 31 st, 2013 Northern Hydrometeorology Group, UNBC

17. VIC model application to the Fraser River Basin (FRB) The Variable Infiltration Capacity (VIC) model has been applied to the Fraser River Basin (Liang et al. 1994; 1996). The model is run at ¼ ◦ and is forced by daily atmospheric conditions sourced from Shi (2012). The calibration period spans 1949-1968 and the validation period covers 1969-2006 Trends assessed with Mann-Kendall Test (significant when p < 0.05).

18. Air Temperature Precipitation

19. NSE = 0.93 (0.86)NSE = 0.93 (Calibration) NSE = 0.85 (Validation)

22. r = 0.75

23. R SR = SWEmax/R r = 0.84

24. CONCLUSIONSCONCLUSIONS FRB air temperatures have warmed by 1.5 o C while precipitation remained stable over water years 1949-2006. This has led to significant declines (~100 mm SWE) in snow accumulation across the FRB. This has led to significant declines (~100 mm SWE) in snow accumulation across the FRB. Over the period of study, the contribution of snow to runoff generation for the Fraser River at Hope, BC has declined by 22% and it is transitioning to a hydrid/pluvial system by ~2025-2045. Over the period of study, the contribution of snow to runoff generation for the Fraser River at Hope, BC has declined by 22% and it is transitioning to a hydrid/pluvial system by ~2025-2045. 24

25. – RESEARCH COLLABORATION Closely collaborating with C. Derksen and R. Brown for their data input, acquisition, and expertise. Closely collaborating with C. Derksen and R. Brown for their data input, acquisition, and expertise. – DATA ACQUISITION D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have kindly provided the National Oceanic Atmospheric Administration (NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask). D. A. Robinson and T. Estilow from Rutgers Global Snow Lab have kindly provided the National Oceanic Atmospheric Administration (NOAA) weekly SCE data and ancillary data (e.g., land/ocean mask). – REGIONAL CLUSTERS Stephen recently participated online in the “Eastern Cluster” regional meeting held in Waterloo. Stephen recently participated online in the “Eastern Cluster” regional meeting held in Waterloo. – MEDIA ATTENTION & OUTREACH A press release announcing the CCAR funding received by Stephen as part of the CanSISE was issued by UNBC on June 24 th, 2013. Following this, Stephen conducted a series of interviews with local media, including CBC Radio Prince George, the Wolf radio station, and CKPG television. A press release announcing the CCAR funding received by Stephen as part of the CanSISE was issued by UNBC on June 24 th, 2013. Following this, Stephen conducted a series of interviews with local media, including CBC Radio Prince George, the Wolf radio station, and CKPG television.

26. -RESEARCH COLLABORATION Closely collaborating with Dr. Dennis Lettenmaier’s group at University of Washington for the VIC model application and UW alumni Huilin Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada). Closely collaborating with Dr. Dennis Lettenmaier’s group at University of Washington for the VIC model application and UW alumni Huilin Gao (Texas A&M) and Xiaogang Shi (NHRC/Environment Canada). Further collaboration with hydrologists at PCIC for future projections of Fraser River Basin hydrology (2013/11/1) Further collaboration with hydrologists at PCIC for future projections of Fraser River Basin hydrology (2013/11/1) -CANSISE OUTREACH & DISSEMINATION Stephen led an interactive discussion on watershed stewardship in the context of climate change with the Northern Provincial Government Water Stewardship Group at UNBC (2013/10/9). Stephen led an interactive discussion on watershed stewardship in the context of climate change with the Northern Provincial Government Water Stewardship Group at UNBC (2013/10/9). DK presented recent progress on hydrologic simulations of the FRB at Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1) DK presented recent progress on hydrologic simulations of the FRB at Duke (2013/09/9), UW (2013/10/16) and PCIC (2013/11/1)

27. ACKNOWLEDGEMENTSACKNOWLEDGEMENTS D. A. Robinson and T. Estilow from Rutgers Global Snow Lab for providing the SCE and ancillary data. D. A. Robinson and T. Estilow from Rutgers Global Snow Lab for providing the SCE and ancillary data. R. Brown (Ouranos) and C. Derksen (Environment Canada) for data and assistance with this work. R. Brown (Ouranos) and C. Derksen (Environment Canada) for data and assistance with this work. D. Lettenmaier, X. Shi and H. Gao for assistance with VIC model implementation over the Fraser River Basin. D. Lettenmaier, X. Shi and H. Gao for assistance with VIC model implementation over the Fraser River Basin. Funding provided by the government of Canada’s NSERC CCAR initiative grant awarded to the CanSISE Network. Funding provided by the government of Canada’s NSERC CCAR initiative grant awarded to the CanSISE Network. 27

28. REFERENCESREFERENCES Brown, R. D., C. Derksen, and L. Wang, 2010: A multi-data set analysis of variability and change in Arctic spring snow cover extent, 1967–2008, J. Geophys. Res., 115, D16111, doi:10.1029/2010JD013975. Brown, R. D. and P. W. Mote, 2009: The response of northern hemisphere snow cover to a changing climate, J. Clim., 22, 2124–2145, doi: http://dx.doi.org/10.1175/2008JCLI2665.1. Derksen, C. and R. D. Brown, 2012: Spring snow cover extent reductions in the 2008–2012 period exceeding climate model projections, Geophys. Res. Lett., 39, L19504, doi: 10.1029/2012GL053387. Déry, S. J. and R. D. Brown, 2007: Recent Northern Hemisphere snow cover extent trends and implications for the snow-albedo feedback, Geophys. Res. Lett., 34, L22504, doi: 10.1029/2007GL031474. 28

29. 29

30. 30

31. 31