Upload
edmund-simon
View
218
Download
0
Tags:
Embed Size (px)
Citation preview
Monitoring polar climate change from space
Thorsten Markus Cryospheric Sciences Branch
NASA Goddard Space Flight CenterGreenbelt, MD
IPY sea ice project in the Antarctic sea ice
The big news last year: The record minimum in Arctic sea ice
Data from satellite passive microwave data
2007Previous minimum
2005
From Rothrock et al.
From Holland and Bitz, 2006
February 1996 September 1996
February 1996 September 1996
Importance of sea ice (1): Global energy balance; Ice/snow albedo feedback
Ocean
Forest
Snow/ice
Importance of sea ice (2): Ocean circulation
What makes the ocean move?1) Wind-driven surface currents 2) Thermohaline circulation
Change in temperature 30 years after collapse of the thermohaline circulation
Michael Vellinga, Hadley Centre
Importance of sea ice (3): Ecology, e.g. polar bears
February 1996 September 1996
??
From Gordon and Comiso, 1988
Moisture flux
Albedo
Ice drift
PrecipitationProcesses:
Warmer temperatures
More moisture
More precipitation
More freshwater input into ocean
More stable Southern Ocean
Less entrainment of WDW
Antarctic sea ice increase with global warming?
More sea ice production
Warmer temperatures
More moisture
More precipitation
More freshwater input into ocean
More stable Southern Ocean
Less entrainment of WDW
Antarctic sea ice increase with global warming?
More sea ice production
Thicker snowon sea ice
More snow-to-ice conversion
More thermal insulation
Less basal freezing
Change in sea ice volume as a function of precipitation(Balance between thermal insulation and snow-to-ice conversion)
IPY sea ice campaign in the Antarctic sea icePart of the project was dedicated to validate ICESat measurements
What is ICESat?
hs
hi
hf
i
s
w
ICESat (laser altimeter)
Cryosat2 (radar altimeter, 2009)
hs = snow depthhi = ice thickness hf = freeboard
What is missing? The 3rd dimension!
Preliminary ICESat freeboard measurements (for cloud-free areas only) on top of AMSR-E sea ice concentrations.
ICESat-derived freeboard(the height over the sea ice above water)
It is a long process to carefully validate satellite measurements of the polar regions and international collaboration is essential.
The polar regions are experiencing drastic changes and we still don’t fully understand all the processes but we cannot effort to turn our heads away.