CanSISE Undergraduate Internship Matthew Pittana York University Christian Haas Group.
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Transcript of CanSISE Undergraduate Internship Matthew Pittana York University Christian Haas Group.
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
3
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 - -
4
Typical Ice Mass Balance Buoy (IMB) Seasonal Cycle
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
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)
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
8
Example of Grid – ERA Interim Surface Pressure
9
Example of IMB Tracking
10
Example of IMB Tracking cont.
11
ERA Interim and IMB 2012B 2m Temperature Merged
12
NCEP-DOE R2 and IMB 2012B 2m Temperature Merged
13
ERA Interim and IMB 2012B Surface Pressure Merged
14
NCEP-DOE R2 and IMB 2012B Surface Pressure Merged
15
Assessment of Data Extraction Method
Validated by merged temperature and pressure plots
Ready to merge IMB and reanalysis snow depth
16
ERA Interim and IMB 2012B SSP/Snow Depth Merged
17
NCEP-DOE R2 and IMB 2012B SSP/Snow Depth Merged
18
ERA Interim Snow Depth
19
NCEP-DOE R2 Snow Depth
20
ERA Interim Snow Depth and Snowfall Merged with IMB 2012B SSP
Sno
wfa
ll (m
of
wa
ter
equi
v.*1
00-0
.8)
21
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
)
22
ERA Interim and IMB 2012D SSP/Snow Depth Merged
23
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
)
24
ERA Interim and IMB 2012G SSP/Snow Depth Merged
25
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
27
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
)
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 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
30
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)
31
Conclusions
Insufficient representation of snow causes high uncertainty of thermodynamic ice growth
Insufficient representation of snow causes uncertainty in climate model projections
32
Next Steps
Quantitatively analyze agreements between observed and modelled variables
Merge in situ measurements with CanSIPS data
33
Thank you!
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/