COMPARING SEA ICE MASS BALANCE BUOY SNOW DEPTH MEASUREMENTS WITH

REANALYSIS DATA

CanSISE Undergraduate Internship

Matthew PittanaYork 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 measurementsDemonstrate seasonal variationsProvide in situ observations essential for

comparison to model data

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Ice Mass Balance Buoys InvestigatedBuoy I.D. Deployment

LocationIce Type Organization/

Institution

2012B Central Arctic (North Pole)

Multi-year ice NPEO, WHOI

2012D Central Arctic (north of

Ellesmere Isl.

First-year ice U of Alberta

2012G Central Arctic (north of Queen E. Islands)

First-year ice AARI Ice Camp

2013A Canadian Islands

Fast ice Christian Haas, York U

and Eric Brossier

2013F Beaufort Sea - -

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Typical Ice Mass Balance Buoy (IMB) Seasonal Cycle

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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

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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)

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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

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Example of Grid – ERA Interim Surface Pressure

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Example of IMB Tracking

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Example of IMB Tracking cont.

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ERA Interim and IMB 2012B 2m Temperature Merged

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

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ERA Interim and IMB 2012B Surface Pressure Merged

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NCEP-DOE R2 and IMB 2012B Surface Pressure Merged

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Assessment of Data Extraction Method

Validated by merged temperature and pressure plots

Ready to merge IMB and reanalysis snow depth

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ERA Interim and IMB 2012B SSP/Snow Depth Merged

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

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ERA Interim Snow Depth

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NCEP-DOE R2 Snow Depth

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ERA Interim Snow Depth and Snowfall Merged with IMB 2012B SSP

Sno

wfa

ll (m

of

wa

ter

equi

v.*1

00-0

.8)

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NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2012B SSP

Pre

cipi

tatio

n R

ate

((kg

/m^2

/s)*

5000

-0.8

)

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ERA Interim and IMB 2012D SSP/Snow Depth Merged

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NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2012D SSP

Pre

cipi

tatio

n R

ate

((kg

/m^2

/s)*

1000

-0.2

)

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ERA Interim and IMB 2012G SSP/Snow Depth Merged

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NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2012G SSP

Pre

cipi

tatio

n R

ate

((kg

/m^2

/s)*

1000

)

26

ERA Interim and IMB 2013F SSP/Snow Depth Merged

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NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2013F SSP

Pre

cipi

tatio

n R

ate

((kg

/m^2

/s)*

1000

-0.1

)

28

NCEP-DOE R2 Snow Depth and Precip Rate Merged with IMB 2013A SSP

Pre

cipi

tatio

n R

ate

((kg

/m^2

/s)*

1000

)

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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 areaAblation periods often correlate with IMB dataSnow depths usually do not reflect IMB dataPrecipitation events often coincide with

increases/decreases in SSPPrecipitation events sometimes coincide with

increases/decreases in modelled snow depth

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Significance of Results

Snow on sea ice has important influence on climate systemNo 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)

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Conclusions

Insufficient representation of snow causes high uncertainty of thermodynamic ice growth

Insufficient representation of snow causes uncertainty in climate model projections

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Next Steps

Quantitatively analyze agreements between observed and modelled variables

Merge in situ measurements with CanSIPS data

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Thank you!

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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/