Transcript Earth`s Climate

Changes in Ice Sheets and Snow Cover
Snow/Ice Report
Greenland
Antarctica
Snow Cover Trends
For Next Class: Read IPCC AR5 Ch. 4 (pp. 323-343)
Observed Variations in the Cryosphere
Greenland and Antarctica
Why are Greenland and Antarctica important in
the context of Global Climate Change?
Techniques for Monitoring Ice Sheets?
Greenland Ice Sheet
Phot credit: Broken Inaglory
The Greenland Ice Sheet is a huge glacier
Photo by Lora Koenig / NASA
Greenland Ice
Sheet has a
maximum
thickness of ~3.3
km (2 mi.)
Photo credit: NASA
Large Melt Events Occurred in July 2012
Total melt~ 43%
No melt
Melt seen by
two or more
sensors
Melt seen by
only one sensor
Land
Credit: NASA – GSFC & JPL
Large Melt Events Occurred in July 2012
Total melt~ 43%
No melt
Total melt~ 99%
Melt seen by
two or more
sensors
Melt seen by
only one sensor
Land
Credit: NASA – GSFC & JPL
Large Melt Events Occurred in July 2012
Total melt~ 43%
No melt
Total melt~ 99%
Melt seen by
two or more
sensors
Total melt~ 45%
Melt seen by
only one sensor
Land
Credit: NASA – GSFC & JPL
Large Melt Events Occurred in July 2012
Total melt~ 43%
No melt
Total melt~ 99%
Melt seen by
two or more
sensors
Total melt~ 45%
Melt seen by
only one sensor
Total melt~ 79%
Land
Credit: NASA – GSFC & JPL
Air Temperature Data from Summit Station, Greenland
Data courtesy of Tom Mefford, NOAA; graphic created by Mike Schnaubelt and
Christopher Shuman, UMBC JCET.
Emanating from the periphery of the ice sheet are many
smaller ice streams and outlet glaciers that drain the main ice
sheet and release icebergs into the ocean
MODIS image 5 July 2003
Earth Observatory
Retreat of Jakobshavn Glacier, SW Greenland
18 June 2003 MISR image from NASA/Earth Observatory
http://earthobservatory.nasa.gov/IOTD/view.php?id=5086
NASA/USGS image courtesy of the Science Visualization Studio, at GSFC
Retreat of Jakobshavn Glacier, Greenland
Greenland Ice Sheet
Direction of ice flow
Ocean / fjord
https://www.youtube.com/watch?v=hC3V
TgIPoGU
IPCC AR5
IPCC AR5
IPCC AR5
Causes of Changes in Ice Sheets?
Ice Sheet Summary
Total ice loss from both Greenland and
Antarctica between 1992 and 2011 was
equivalent to 11.7 mm of sea level.
Future destabilization of ice sheets could
cause sea level to rise substantially.
Seasonal Snow Cover
Photo credit: D.K. Hall / NASA
Snow Cover
Why do we care about snow cover from a climate
and societal perspective?
Snow and Climate
•Snow covers over 40% of the Northern Hemisphere land
surface in a typical winter
•High albedo and heat capacity of snow cover influence
energy exchange with the atmosphere
•Can lower temperatures over large areas
•Influences regional weather patterns and monsoon
strength
•Additionally, snow cover represents a key indicator of
climate change
Snow Mapping from Space in 1962
Satellite Snow-Cover Products
Feb. 2004
MODIS monthly snow-cover map
National Ice Center
(NIC) snow-cover
map
28 Dec. 2010
Northeastern U.S. MODIS swath
fractional snow-cover map
IMS
12 Feb. 2012
Snow in North Carolina
14 February 2010
Cape
Hatteras
Harkers Is.
MODIS Rapid Response Team
Snow in the Sierra Nevada, Calif.
1 October 2004
NASA/MODIS
Snow Cover in North America
Sept. 2002 – Jun. 2003
North Carolina
MODIS SVS / NASA
Northern Hemisphere monthly average snow extents
for the past three decades*
*compared the long term average
D. Robinson / Rutgers Univ.
Snow-covered area derived from station data (before 1972) and NOAA satellite data
(after 1972); the smooth curve shows decadal variations (from Brown, 2000).
IPCC AR5
1988-2004 period was
characterized by warmer
NH spring conditions and
earlier snowmelt
NH Snow Cover extent has been
well above normal the past few winters
until 2015-16!
Especially over the mid-latitudes
(35-55 N).
Possibly related to the Warm Arctic
Cold Continents pattern (Cohen 2010).
Observed Variations in the Cryosphere