1. CanSISE Undergraduate Internship Matthew Pittana York University Christian Haas Group

2. Introduction  Purpose to assess accuracy of reanalysis snow depth outputs on sea ice over Arctic Ocean  Drifting ice mass balance buoys Provide meteorological, ice, and snow surface position measurements Demonstrate seasonal variations Provide in situ observations essential for comparison to model data 2

3. Ice Mass Balance Buoys Investigated 3 Buoy I.D.Deployment Location Ice TypeOrganization/ Institution 2012BCentral Arctic (North Pole) Multi-year iceNPEO, WHOI 2012DCentral Arctic (north of Ellesmere Isl. First-year iceU of Alberta 2012GCentral Arctic (north of Queen E. Islands) First-year iceAARI Ice Camp 2013ACanadian Islands Fast iceChristian Haas, York U and Eric Brossier 2013FBeaufort Sea--

4. Typical Ice Mass Balance Buoy (IMB) Seasonal Cycle 4

5. Snow Surface Position (SSP)  Reference level is 0 – snow-ice interface at beginning of buoy lifetime  Snow ablation period followed by melting of surface ice – relative SSP falls below 0  Accumulation begins at SSP below 0 at onset of winter 5

6. ERA Interim Daily Fields and NCEP- DOE Reanalysis 2  NetCDF files  Variables cover entire globe (gridded data)  Variables output at 6 hour intervals (4x daily) 6

7. Merging Reanalysis Data with IMB Data  Reanalysis time spans coincide with IMB time spans  For each model output one grid value extracted corresponding to nearest location of IMB at particular time 7

8. Example of Grid – ERA Interim Surface Pressure 8

9. Example of IMB Tracking 9

10. Example of IMB Tracking cont. 10

11. ERA Interim and IMB 2012B 2m Temperature Merged 11

12. NCEP-DOE R2 and IMB 2012B 2m Temperature Merged 12

13. ERA Interim and IMB 2012B Surface Pressure Merged 13

14. NCEP-DOE R2 and IMB 2012B Surface Pressure Merged 14

15. Assessment of Data Extraction Method  Validated by merged temperature and pressure plots  Ready to merge IMB and reanalysis snow depth 15

16. ERA Interim and IMB 2012B SSP/Snow Depth Merged 16

17. NCEP-DOE R2 and IMB 2012B SSP/Snow Depth Merged 17

18. ERA Interim Snow Depth 18

19. NCEP-DOE R2 Snow Depth 19

20. ERA Interim Snow Depth and Snowfall Merged with IMB 2012B SSP 20 Snowfall (m of water equiv.*100-0.8)

21. NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2012B SSP 21 Precipitation Rate ((kg/m^2/s)*5000-0.8)

22. ERA Interim and IMB 2012D SSP/Snow Depth Merged 22

23. NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2012D SSP 23 Precipitation Rate ((kg/m^2/s)*1000-0.2)

24. ERA Interim and IMB 2012G SSP/Snow Depth Merged 24

25. NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2012G SSP 25 Precipitation Rate ((kg/m^2/s)*1000)

26. ERA Interim and IMB 2013F SSP/Snow Depth Merged 26

27. NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2013F SSP 27 Precipitation Rate ((kg/m^2/s)*1000-0.1)

28. NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2013A SSP 28 Precipitation Rate ((kg/m^2/s)*1000)

29. Qualitative Snow Depth and Precipitation Comparisons  ERA Interim Does not display snow depth or its variance  NCEP-DOE R2 Displays snow depth variance over time and area Ablation periods often correlate with IMB data Snow depths usually do not reflect IMB data Precipitation events often coincide with increases/decreases in SSP Precipitation events sometimes coincide with increases/decreases in modelled snow depth 29

30. Significance of Results  Snow on sea ice has important influence on climate system No snow cover – lower albedo, melting of ice occurs faster (greater ice growth in winter ) Snow cover – higher albedo, insulation of sea ice beneath, slower melting of ice (slower ice growth in winter) 30

31. Conclusions  Insufficient representation of snow causes high uncertainty of thermodynamic ice growth  Insufficient representation of snow causes uncertainty in climate model projections 31

32. Next Steps  Quantitatively analyze agreements between observed and modelled variables  Merge in situ measurements with CanSIPS data 32

33. Thank you! 33

34. References/Acknowledgements  Ice Mass Balance Buoy Data: Perovich, D., J. Richter-Menge, B. Elder, T. Arbetter, K. Claffey, and C. Polashenski, Observing and understanding climate change: Monitoring the mass balance, motion, and thickness of Arctic sea ice, http://IMB.crrel.usace.army.mil, 2013.  ERA Interim Daily Fields ECMWF ERA-Interim data used in this study/project have been provided by ECMWF  NCEP-DOE Reanalysis 2 NCEP_Reanalysis 2 data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.esrl.noaa.gov/psd/ 34