Transcript Marginal Ice zone

Marginal Ice zone
Some definitions:
•
Wadhams (1986) : "that part of the ice cover which is close
enough to the open ocean boundary to be affected by its
presence".
•
Mohn Sverdrup Center: “The marginal ice zone (MIZ) is
defined as the area where open ocean processes, including
specifically ocean waves, alter significantly the dynamical
properties of the sea ice cover.”
Where is the Marginal Ice Zone ?
The variability of ice concentration outline areas where marginal ice zone exists
September
March
Standard deviation of sea ice concentration. 1979-2009
More mixed ocean/ice regions after 2007 ?
There appears to be a shift in mean
Arctic Ocean ice concentration after
2007. Reprocessing of 2010-2013
data will reveal more…
(spring 2014)
Average sea ice concentration in March and September,
for ice concentration greater than 15% - North of 80N.
Surface temperature in MIZ
• Reanalysis used to create ice, in situ and
SST match-ups
• Matches in East Greenland Current
•Large SST within region with mixed ice and
ocean
• Similar signal for ARC and Pathfinder
Validating SST products in MIZ
• Reanalysis sea ice-in situ + satellite
match-ups
•Remarkable small and stable bias for
ice concentration < 60 %
Ice and Sea Surface Temperature
- in situ measurements from Oden 2012
Simultaneous sampling from Monkey Island:
• Thermal InfraRed surface temperatures
• Ship air temperatures
• L-Band microwave integrated temperatures
• Photo based ice concentration setup
Measuring Ice concentration
- in situ
GoPro photo ice concentration sampling in 1-minute resolution.
(38 periods of three hours)
GoPro photo of Arctic sea ice
(crosstrack from Monkey Island).
Oden, Summer 2012.
Photo classification:
White is Ice, colors are No-Ice
Marginal Ice Zone
- temperatures and IC
IC varying between 0.3 and 0.8
-> Skin temperatures reflect
alternately water, ice and mixing
temperatures.
IC correlated with skin
temperatures -> water is colder
than ice surface.
The air temperature is the coldest of 5 ship
thermometers. However, the measurement 3-hour sampling of coincident measurements of ship air
must be read with causion as ship heating temperatures (blue), TIR skin temperatures (green) and
may influence the measure…
photo determined ice concentrations.
Metop-A SST + MIZ + IST product
• IST algorithm
• SST algorithm
• MIZ (linear combination of IST + SST)
• T10.8 determines the algorithm
• Level 3 fields available at: polarportal.dk
Summary/Challenges
• MIZ covers large parts of the Arctic ocean
• Indications that larger percentage of ice covered waters have smaller
concentration
• In situ ice concentration data set available
• Interesting IC and ST relationship
Future work
• Determine the SST signal within MIZ for different ic conc, regions and
seasons
• Compare SST and Metop-a in MIZ
• Determine the impact of SST gradients in MIZ on SST performance
• Collect in situ observations in MIZ
• Verify and update MIZ algorithm in Metop-A
• Use SST versus IC relationship in Arctic Level 4
High latitude DMI-ISAR deployments
•
•
7 week deployed at ODEN icebreaker
Autonomous deployment July-November 2013
•
•
•
Planned
Activ circumpolar expedition (2014, 2015)
RAL line, Denmark-Greenland